| 1. |
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| 2. |
- Salvo, Gloria, et al.
(författare)
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Open vs minimally invasive radical trachelectomy in early-stage cervical cancer : International Radical Trachelectomy Assessment Study
- 2022
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Ingår i: American Journal of Obstetrics and Gynecology. - : Elsevier BV. - 0002-9378 .- 1097-6868. ; 226:1, s. 1-97
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Tidskriftsartikel (refereegranskat)abstract
- Background: Minimally invasive radical trachelectomy has emerged as an alternative to open radical hysterectomy for patients with early-stage cervical cancer desiring future fertility. Recent data suggest worse oncologic outcomes after minimally invasive radical hysterectomy than after open radical hysterectomy in stage I cervical cancer. Objective: We aimed to compare 4.5-year disease-free survival after open vs minimally invasive radical trachelectomy. Study Design: This was a collaborative, international retrospective study (International Radical Trachelectomy Assessment Study) of patients treated during 2005–2017 at 18 centers in 12 countries. Eligible patients had squamous carcinoma, adenocarcinoma, or adenosquamous carcinoma; had a preoperative tumor size of ≤2 cm; and underwent open or minimally invasive (robotic or laparoscopic) radical trachelectomy with nodal assessment (pelvic lymphadenectomy and/or sentinel lymph node biopsy). The exclusion criteria included neoadjuvant chemotherapy or preoperative pelvic radiotherapy, previous lymphadenectomy or pelvic retroperitoneal surgery, pregnancy, stage IA1 disease with lymphovascular space invasion, aborted trachelectomy (conversion to radical hysterectomy), or vaginal approach. Surgical approach, indication, and adjuvant therapy regimen were at the discretion of the treating institution. A total of 715 patients were entered into the study database. However, 69 patients were excluded, leaving 646 in the analysis. Endpoints were the 4.5-year disease-free survival rate (primary), 4.5-year overall survival rate (secondary), and recurrence rate (secondary). Kaplan-Meier methods were used to estimate disease-free survival and overall survival. A post hoc weighted analysis was performed, comparing the recurrence rates between surgical approaches, with open surgery being considered as standard and minimally invasive surgery as experimental. Results: Of 646 patients, 358 underwent open surgery, and 288 underwent minimally invasive surgery. The median (range) patient age was 32 (20–42) years for open surgery vs 31 (18–45) years for minimally invasive surgery (P=.11). Median (range) pathologic tumor size was 15 (0–31) mm for open surgery and 12 (0.8–40) mm for minimally invasive surgery (P=.33). The rates of pelvic nodal involvement were 5.3% (19 of 358 patients) for open surgery and 4.9% (14 of 288 patients) for minimally invasive surgery (P=.81). Median (range) follow-up time was 5.5 (0.20–16.70) years for open surgery and 3.1 years (0.02–11.10) years for minimally invasive surgery (P<.001). At 4.5 years, 17 of 358 patients (4.7%) with open surgery and 18 of 288 patients (6.2%) with minimally invasive surgery had recurrence (P=.40). The 4.5-year disease-free survival rates were 94.3% (95% confidence interval, 91.6–97.0) for open surgery and 91.5% (95% confidence interval, 87.6–95.6) for minimally invasive surgery (log-rank P=.37). Post hoc propensity score analysis of recurrence risk showed no difference between surgical approaches (P=.42). At 4.5 years, there were 6 disease-related deaths (open surgery, 3; minimally invasive surgery, 3) (log-rank P=.49). The 4.5-year overall survival rates were 99.2% (95% confidence interval, 97.6–99.7) for open surgery and 99.0% (95% confidence interval, 79.0–99.8) for minimally invasive surgery. Conclusion: The 4.5-year disease-free survival rates did not differ between open radical trachelectomy and minimally invasive radical trachelectomy. However, recurrence rates in each group were low. Ongoing prospective studies of conservative management of early-stage cervical cancer may help guide future management.
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| 3. |
- An, Rong, et al.
(författare)
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Atomic force microscopy probing interactions and microstructures of ionic liquids at solid surfaces
- 2022
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Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; :14, s. 11098-11128
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Forskningsöversikt (refereegranskat)abstract
- Ionic liquids (ILs) are room temperature molten salts that possess preeminent physicochemical properties and have shown great potential in many applications. However, the use of ILs in surface-dependent processes, e.g. energy storage, is hindered by the lack of a systematic understanding of the IL interfacial microstructure. ILs on the solid surface display rich ordering, arising from coulombic, van der Waals, solvophobic interactions, etc., all giving near-surface ILs distinct microstructures. Therefore, it is highly important to clarify the interactions of ILs with solid surfaces at the nanoscale to understand the microstructure and mechanism, providing quantitative structure–property relationships. Atomic force microscopy (AFM) opens a surface-sensitive way to probe the interaction force of ILs with solid surfaces in the layers from sub-nanometers to micrometers. Herein, this review showcases the recent progress of AFM in probing interactions and microstructures of ILs at solid interfaces, and the influence of IL characteristics, surface properties and external stimuli is thereafter discussed. Finally, a summary and perspectives are established, in which, the necessities of the quantification of IL–solid interactions at the molecular level, the development of in situ techniques closely coupled with AFM for probing IL–solid interfaces, and the combination of experiments and simulations are argued.
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| 4. |
- Chen, Jingjing, et al.
(författare)
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Mechanism of waste-heat recovery from slurry by scraped-surface heat exchanger
- 2017
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Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 207, s. 146-155
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Tidskriftsartikel (refereegranskat)abstract
- Waste-heat recovery from discharged slurries can improve the net raw biogas production in the bio-methane process in order to meet the demand for a next-generation of anaerobic digestion. In this study, a numerical model of a scraped-surface heat exchanger was proposed with the consideration of the complete and precise rheological behaviour of the slurry of animal manure for the first time for achieving highly efficient waste-heat recovery. The rheological model results were verified with new experimental data measured in this work. Subsequently, the convective heat-transfer coefficient of the scraped-surface heat exchanger was calculated numerically with the proposed numerical model, and the performance was determined. Then, the contributions of waste-heat recovery from the slurry to the biogas production using a general shell-and-tube heat exchanger and the scraped-surface heat exchanger were calculated quantitatively and compared. For the case of scraped-surface heat exchanger, the increase of net raw biogas production can be up to 8.53%, which indicates that there is a great potential to increase the net raw biogas production in the bio-methane process using a scraped-surface heat exchanger with low-cost equipment and a compactible structure.
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| 5. |
- Chen, Yifeng, et al.
(författare)
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Developing hybrid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide/titanium dioxide/water absorbent for CO2 separation
- 2022
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Ingår i: Applied Energy. - : Elsevier Ltd. - 0306-2619 .- 1872-9118. ; 326
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Tidskriftsartikel (refereegranskat)abstract
- The development of novel absorbents is essential for improving CO2 separation technology. In this study, 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide/titanium dioxide/water ([Hmim][NTf2]/TiO2-H2O) was developed to separate CO2, where the thermodynamic and kinetic experiments were conducted, and Henry's constant and the liquid-side mass-transfer coefficient were determined accordingly. Furthermore, CO2 separation performance in a bubble tower was validated. A previously proposed index named “absorption ability” (AA) was used to predict and compare the experimental results. Additionally, the cost of biogas upgrading (i.e., CO2 removal for biogas purification) using [Hmim][NTf2]/TiO2-H2O was estimated. The results showed that for the developed [Hmim][NTf2]/TiO2-based technology, the average CO2 mass-transfer rate was increased by 20.0% compared with the current commercialized technology, and the contributions from the thermodynamic and kinetic aspects were 2.5% and 17.5%, respectively. The cost of biogas upgrading was 16.6% lower. In addition, AA successfully predicted the performance of CO2 separation technologies, achieving an average relative deviation of 8.1%.
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| 6. |
- Chen, Yifeng, et al.
(författare)
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Kinetics study and performance comparison of CO2 separation using aqueous choline-amino acid solutions
- 2021
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Ingår i: Separation and Purification Technology. - : Elsevier. - 1383-5866 .- 1873-3794. ; 261
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Tidskriftsartikel (refereegranskat)abstract
- The thermodynamic and kinetic properties of CO2 in aqueous choline-amino acids ([Cho][AA]s) are important information to demonstrate their performance. In this study, the apparent kinetic properties of CO2 in the five aqueous [Cho][AA]s, including the liquid-side mass-transfer coefficients, enhancement factor, and reaction rate constant, were systematically studied. Furthermore, a new ‘‘absorption ability’’ (AA) index was proposed, combining the apparent kinetic properties determined in this study and thermodynamic properties determined in our previous study. The CO2 separation performance using aqueous [Cho][AA]s was evaluated based on the AA and CO2 desorption enthalpy values. The results show that 30 wt% aqueous choline-serine is a promising absorbent for CO2 separation, and it is comparable to aqueous monoethanolamine.
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| 7. |
- Deng, Pengyi, et al.
(författare)
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Optimal online energy management strategy of a fuel cell hybrid bus via reinforcement learning
- 2024
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Ingår i: Energy Conversion and Management. - 0196-8904. ; 300
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Tidskriftsartikel (refereegranskat)abstract
- An energy management strategy (EMS) based on reinforcement learning is proposed in this study to enhance the fuel economy and durability of a fuel cell hybrid bus (FCHB). Firstly, a comprehensive powertrain system model for the FCHB is established, mainly including the FCHB's power balance, fuel cell system (FCS) efficiency, and aging models. Secondly, the state–action space, state transition probability matrix (TPM), and multi-objective reward function of Q-learning algorithm are designed to improve the fuel economy and the durability of power sources. The FCHB's demand power and battery state of charge (SOC) serve as the state variables and the FCS output power is used as the action variable. Using the demonstration FCHB data, a state TPM is created to represent the overall operation. Finally, an EMS employing Q-learning is formulated to optimize the fuel economy of FCHB, maintain battery SOC, suppress FCS power fluctuations, and enhance FCS lifetime. The proposed EMS is tested and verified through hardware-in-the-loop (HIL) tests. The simulation results demonstrate the effectiveness of the proposed strategy. Compared to a rule-based EMS, the Q-learning-based EMS can improve the energy economy by 7.8%. Furthermore, it is only a 3.7% difference to the best energy economy under dynamic optimization, while effectively reducing the decline and enhancing the durability of the FCS.
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| 8. |
- Dong, Yihui, et al.
(författare)
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Excellent Trace Detection of Proteins on TiO2Nanotube Substrates through Novel Topography Optimization
- 2020
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 124:50, s. 27790-27800
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Tidskriftsartikel (refereegranskat)abstract
- For improving the surface-enhanced Raman scattering (SERS) performance of nanomaterials to achieve trace detection of proteins and complex biological systems, structural and topographical control is one of the important strategies. In this work, a facial and effective method to optimize the topography of TiO2 nanotube arrays (TNAs) is demonstrated, together with a significant enhancement of the SERS performance of cytochrome C (Cyt C) on TNAs. An enhancement factor (EF) up to 104, which is obtained with the newly developed method on the basis of the quantification of atomic force microscopy (AFM)-measured interaction force, is achieved, corresponding to a superior detection limit of Cyt C down to 10-7 M. The main reason is that adjusting the fluoride contents in an electrolyte (from 0.4 to 0.1 wt %) can reduce the content and sizes of cracks, as well as the tube ruptures of TNAs, where the fluoride content at 0.2 wt % can successfully provide the excellent and optimized topography of TNAs. The TNAs with the optimized topography, especially those with larger tube diameters, demonstrated the importance of structural integrity on a remarkably excellent SERS performance in the trace detection of proteins. The proposed method will stimulate the development and optimization of the active substrate on the SERS applications in biology, bioanalysis, and nanoscience. © 2020 American Chemical Society.
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| 9. |
- Gao, Qingwei, et al.
(författare)
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Molecular insight into wetting behavior of deep eutectic solvent droplets on ionic substrates : A molecular dynamics study
- 2020
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Ingår i: Journal of Molecular Liquids. - : Elsevier. - 0167-7322 .- 1873-3166. ; 319
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Tidskriftsartikel (refereegranskat)abstract
- Wetting behavior of droplets made of choline chloride/urea (1:2), an archetypal deep eutectic solvent mixture, is studied using molecular dynamics simulations. The droplets are placed on a smooth model ionic substrate with positive and negative charges of the same magnitude q (0 e ≤ q ≤ 1.0 e), corresponding to a step-by-step change from a hydrophobic to hydrophilic surface. The molecular microstructure of the droplets and their spatial compositions are systematically studied in details on how they both change while gradually moving from hydrophobic to hydrophilic surface. It is observed that urea initially forms a monolayer on the surface with a planar orientation. This layer slowly shrinks while it becomes laterally more and more constrained. It becomes also molecularly more ordered when the surface becomes hydrophilic, at the same time as the contact angles become larger and larger. The anions (Cl-) are continuously pushed further away from the charged surface. While the contact angle increases and wetting decreases, and urea forms even a secondary stable layer where it changes its orientation and turns to have one of its amines facing up and carbonyl down. The average number of urea-urea H-bonds decreases linearly while the number of ion-pair contacts increases when the urea molecules are separating from the mixture. Our analysis gives a clear molecular understanding of the process and can be useful in many applications from membrane separation to catalysis.
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| 10. |
- Haffouz, Sofiane, et al.
(författare)
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Bright Single InAsP Quantum Dots at Telecom Wavelengths in Position-Controlled InP Nanowires : The Role of the Photonic Waveguide
- 2018
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Ingår i: Nano letters (Print). - : AMER CHEMICAL SOC. - 1530-6984 .- 1530-6992. ; 18:5, s. 3047-3052
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Tidskriftsartikel (refereegranskat)abstract
- We report on the site-selected growth of bright single InAsP quantum dots embedded within InP photonic nanowire waveguides emitting at telecom wavelengths. We demonstrate a dramatic dependence of the emission rate on both the emission wavelength and the nanowire diameter. With an appropriately designed waveguide, tailored to the emission wavelength of the dot, an increase in the count rate by nearly 2 orders of magnitude (0.4 to 35 kcps) is obtained for quantum dots emitting in the telecom O-band, showing high single-photon purity with multiphoton emission probabilities down to 2%. Using emission-wavelength-optimized waveguides, we demonstrate bright, narrow-line-width emission from single InAsP quantum dots with an unprecedented tuning range of 880 to 1550 nm. These results pave the way toward efficient single-photon sources at telecom wavelengths using deterministically grown InAsP/InP nanowire quantum dots.
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| 11. |
- Huang, Xianzhu, et al.
(författare)
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Flow-resistance analysis of nano-confined fluids inspired from liquid nano-lubrication: A review
- 2017
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Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 25:11, s. 1552-1562
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Tidskriftsartikel (refereegranskat)abstract
- How to reduce flow resistance of nano-confined fluids to achieve a high flux is a new challenge for modern chemical engineering applications, such as membrane separation and nanofluidic devices. Traditional models are inapplicable to explain the significant differences in the flow resistance of different liquid–solid systems. On the other hand, friction reduction in liquid nano-lubrication has received considerable attention during the past decades. Both fields are exposed to a common scientific issue regarding friction reduction during liquid–solid relative motion at nanoscale. A promising approach to control the flow resistance of nano-confined fluids is to reference the factors affecting liquid nano-lubrication. In this review, two concepts of the friction coefficient derived from fluid flow and tribology were discussed to reveal their intrinsic relations. Recent progress on low or ultra-low friction coefficients in liquid nano-lubrication was summarized based on two situations. Finally, a new strategy was introduced to study the friction coefficient based on analyzing the intermolecular interactions through an atomic force microscope (AFM), which is a cutting-point to build a new model to study flow-resistance at nanoscale.
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| 12. |
- Huang, Xianzhu, et al.
(författare)
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Tribological Properties of Porous PEEK Composites Containing Ionic Liquid under Dry Friction Condition
- 2017
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Ingår i: Lubricants. - Basel : MDPI. - 2075-4442. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- NaCl particles were added into Polyetheretherketone (PEEK) and its composites to produce porous PEEK-based materials by washing NaCl away after the high-temperature compression molding process. After that, an ionic liquid was added into the porous materials under vacuum condition. Carbon fibers (CF), as reinforcement, and PTFE, as an internal solid lubricant, were employed to prepare PEEK composites. Tribological properties under dry friction condition were studied on a ring-on-disc tribo-meter. The influence of CF and PTFE on tribological properties was carefully investigated. The results indicated that, in comparison with traditional PEEK composites (CF/PTFE/PEEK), the porous PEEK composites containing ionic liquid showed much better tribological properties. It is found that CF can help PEEK form effective pores to suck in the ionic liquid resulting in a better tribological performance. CF reinforced porous PEEK containing ionic liquid (p-CF/PEEK + IL) demonstrated the lowest friction coefficient (27% of CF/PTFE/PEEK) and the lowest wear loss (only 0.9% of CF/PTFE/PEEK). Long time tribological test revealed that the wear mass loss comes from the running-in period, while its wear is negligible after this period. It is also found that the addition of PTFE has a negative influence on the tribological behaviors, especially under high sliding velocity and applied load
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| 13. |
- Huangfu, Changan, et al.
(författare)
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Mechanistic Study of Protein Adsorption on Mesoporous TiO2 in Aqueous Buffer Solutions
- 2019
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 35:34, s. 11037-11047
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Tidskriftsartikel (refereegranskat)abstract
- Protein adsorption is of fundamental importance for bioseparation engineering applications. In this work, a series of mesoporous TiO2 with various geometric structures and different aqueous buffer solutions were prepared as platforms to investigate the effects of the surface geometry and ionic strength on the protein adsorptive behavior. The surface geometry of the TiO2 was found to play a dominant role in the protein adsorption capacity when the ionic strength of buffer solutions is very low. With the increase in ionic strength, the effect of the geometric structure on the protein adsorption capacity reduced greatly. The change of ionic strength has the highest significant effect on the mesoporous TiO2 with large pore size compared with that with small pore size. The interaction between the protein and TiO2 measured with atomic force microscopy further demonstrated that the adhesion force induced by the surface geometry reduced with the increase in the ionic strength. These findings were used to guide the detection of the retention behavior of protein by high-performance liquid chromatography, providing a step forward toward understanding the protein adsorption for predicting and controlling the chromatographic separation of proteins.
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| 14. |
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| 15. |
- Li, Li, et al.
(författare)
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Effects of 2-methoxyestradiol on endometrial carcinoma xenografts
- 2007
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Ingår i: Journal of Cancer Research and Clinical Oncology. - : Springer Science and Business Media LLC. - 0171-5216 .- 1432-1335. ; 133:5, s. 315-320
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: We have previously demonstrated that 2-methoxyestradiol (2-ME) inhibits the growth of human endometrial cancer HEC-1-A and RL-95-2 cells in vitro. In this study, we examined the effects of 2-ME on human endometrial carcinoma in severe combined immune deficient (SCID) mice. The potential side effects of 2-ME on SCID mice were also investigated. Methods: Severe combined immune deficient mice were injected with HEC-1-A cells (1 × 10 6/mouse) and a 18 day administration of 2-ME was followed after 1 week cell implantation. Tumor volume, weight, body weight and blood chemistry were determined. Tumor tissues were examined with an antibody against the proliferative cell nuclear antigen (PCNA) and Ki-67. Liver, spleen, kidney, heart, lung and uterus were screened by pathological examinations. Results: 2-ME (100 mg/kg p.o.) did not inhibit the growth of human endometrial carcinoma as compared to control. Necrotic areas were similar in both 2-ME-treated and -untreated tumor tissues. The expressions of PCNA and Ki-67 were similar in 2-ME-treated and untreated tumor sections. The wet weight of uterus was increased to more than threefold. The epithelial cells and glands in endometrium were increased. No significant difference was detected in blood AST, ALT and BUN. Conclusions: 2-ME has no antitumor effects on human endometrial carcinoma in our animal model. Its proliferative effects on endometrium and uterus might limit its use in gynecological cancers.
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| 16. |
- Li, Suyang, et al.
(författare)
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One-pot fabrication of Mo1-xWxS2 alloy nanosheets as SERS substrates with highly Raman enhancement effect and long-term stability
- 2022
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Ingår i: Spectrochimica Acta Part A - Molecular and Biomolecular Spectroscopy. - : Elsevier BV. - 1386-1425 .- 1873-3557. ; 279, s. 121465-
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Tidskriftsartikel (refereegranskat)abstract
- A new Mo1-xWxS2 two-dimensional nanosheets were prepared by the one-pot method. After certain Mo atoms in MoS2 were replaced by W ones in a hydrothermal reduction procedure, Mo1-xWxS2 was formed on the Mo foil. Well enhanced Mo1-xWxS2 nanosheets were prepared when the sodium tungstate concentration got under control. Various characterizations were carried out, which indicate that Mo1-xWxS2 nanosheets with good crystallinity. Compared with MoS2, the Raman intensity of Rhodamine 6G (10-6 M) was amplified by 1.7 times with Mo1-xWxS2 nanosheets as the substrate. The characteristic Raman peaks could still be clearly distinguished until the concentration of Rhodamine 6G (R6G), Methylene blue (MB) and Crystal violet (CV) down to 10-8, 10-8 and 10- 7 M, respectively. With abundant edge active sites that facilitate charge transfer, Mo1-xWxS2 nanosheets could better enhance SERS signals of target detection molecules and get a good linear relationship exists within the concentration and Raman peak strength. In addition, R6G SERS detection also shows excellent reproducibility and long-term stability of this TMDs SERS substrate.
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| 17. |
- Li, Shuai, 1990, et al.
(författare)
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Sound source and pseudo-sound in the near field of a circular cylinder in subsonic conditions
- 2021
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Ingår i: Journal of Fluid Mechanics. - : Cambridge University Press (CUP). - 0022-1120 .- 1469-7645. ; 919:A43
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Tidskriftsartikel (refereegranskat)abstract
- It is well known that the pressure fluctuations on both sides of a cylinder and those in its oscillating near-wake region are both sound sources at low Reynolds and Mach numbers. However, assessment of the propagating capacity and quantification of the radiating versus non-radiating components of these two sound sources are not currently available for this important benchmark aeroacoustic problem. Here, we isolate the radiating acoustic sound sources from the non-radiating hydrodynamic pseudo-sounds by applying the wavelet decomposition technique of Mancinelli et al. (J. Fluid Mech., vol. 813, 2017), previously used in subsonic jet-noise experiments, to decompose the cylinder near-field pressure fluctuations obtained from our direct numerical simulations. Rigorous independence and convergence analyses of the wavelet decomposition procedure are performed. It is found that the radiating acoustic component strongly dominates over the non-radiating hydrodynamic component at near-field locations above and upstream of the cylinder. In the oscillating near-wake region, the hydrodynamic component dominates over the acoustic component at most frequencies, except at the vortex shedding frequency where they exhibit comparable strengths. Furthermore, within the oscillating near-wake region, the overall sound pressure level associated with the hydrodynamic pressure fluctuations exceeds that associated with the acoustic pressure fluctuations. Away from the oscillating near-wake region, the hydrodynamic pressure fluctuations decrease dramatically while the acoustic counterparts decay slowly, demonstrating that the hydrodynamic pressure fluctuation does not propagate, and that the acoustic pressure fluctuation is the only component to propagate to the far field.
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| 18. |
- Liu, Chang, et al.
(författare)
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Determination of the ion exchange process of K2Ti4O9 fibers at constant pH and modeling with statistical rate theory
- 2015
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Ingår i: RSC Advances. - : Royal Society of Chemistry (RSC). - 2046-2069. ; 5:90, s. 73474-73480
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Tidskriftsartikel (refereegranskat)abstract
- The ion exchange kinetics of K2Ti4O9 fibers at constant pH was determined precisely by ion-selective electrodes, and activity coefficients of ions in solutions were calculated by the Lu-Maurer equation. It was found that the equilibrium time and TiO2/K2O molar ratio in the solid phase are more sensitive to pH than to water volume. After that, a two-step exchange kinetics model was developed, in which a statistical rate theory base on chemical potential difference between interface was use to describe surface reaction process instead of an empirical exponential equation. The model shows that the resistance of the surface reaction step, which includes hydration of K+ ions on the surface and their transport in the solid phase, is the main resistance of the ion exchange process.
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| 19. |
- Lu, Xiaohua, et al.
(författare)
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Nano-interface enhanced CO2 absorption and mechanism analysis
- 2020
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Ingår i: Huagong Xuebao/CIESC Journal. - : Materials China. - 0438-1157. ; 71:1, s. 34-42
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Tidskriftsartikel (refereegranskat)abstract
- CO2 capture and separation (CCS) is a key step to mitigate greenhouse gas emissions and develop renewable energy. The trade-off between the rate and efficiency in the CO2 separation process cannot be solved with the traditional process intensification. Using nano-interface to realize process intensification has been widely used in the chemical process with multi-phase transfer, and CO2 separation is one of examples. This review summarizes the research work from the establishment of CO2 transfer model at nano-interface and the resistance regulation, the acquisition of the CO2 chemical potentials at equilibrium and at the nano-interface (the driving force regulation) and the molecular simulation analysis of the interface enhancement mechanism. Based on the theoretical studies, the resistance distribution for the CO2 separation process in a real absorption tower is further analyzed and a "three-stage strengthening scheme" is proposed to decrease the investment and operating costs. © All Right Reserved.
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| 20. |
- Lu, Xiaohua, et al.
(författare)
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Thermodynamic mechanism of complex fluids-solids interfacial interaction
- 2019
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Ingår i: Huagong Xuebao/CIESC Journal. - : Materials China. - 0438-1157. ; 70:10, s. 3677-3689
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Forskningsöversikt (refereegranskat)abstract
- Interfacial transfer at mesoscale is a common issue for all the multi-phase chemical processes, and the related study remains as a scientific challenge due to the complexities. Investigating the interfacial interactions at mesoscale to find out the regulation strategies is the key to realize process-intensification of mass-transfer and reaction for the advanced chemical industries. To accurately describe the behavior of fluids at the interface, a new molecular thermodynamic model that can describe the complex fluid-solid interface interaction. When the molecular thermodynamic modeling method is extended to the nano-micro interfacial transfer needs to be developed, calling for the coordination of advanced experiments at nano-micro scale and molecular with molocular thermodynamic modelling. Atomic force microscopy (AFM), which possess the sensitivity down to nanoscale, can directly obtain the interfacial interaction at nano-micro scale. The quantification of AFM-measured forces can be used to construct the coarse-grained molecular model and describe complex interfacial interaction. Then, the coarse-grained molecular model can reveal the molecular thermodynamic mechanism of nano- and micro- interface transfer, realizing quantitative prediction.
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| 21. |
- Mu, Liwen, et al.
(författare)
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Enriching Heteroelements in Lignin as Lubricating Additives for Bioionic Liquids
- 2016
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 4:7, s. 3877-3887
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Tidskriftsartikel (refereegranskat)abstract
- Depolymerization and modification of lignin have been achieved simultaneously in a one-pot chemical reaction. Two heteroelement-rich modifiers, imidazol-1-yl phosphonic dichloride and 1H-1,2,4-triazol-1-yl phosphonic dichloride, were selected to react with lignin in this work. The modified lignin (m-lignin) is demonstrated as an effective lubricating additive for [choline][amino acid] ([CH][AA]) bioionic liquids. Different characterization techniques have been utilized to study the lignin depolymerization, reaction between lignin and modifiers and m-lignin/[CH][AA] interaction. The effect of the molecular structure of the modifiers on the rheological and tribological properties of m-lignin/[CH][AA] lubricants was systematically investigated. Density function theory is used to calculate the electronic structure of lignin, m-lignin, and [CH][AA]. The atomic natural charge analysis revealed the most negative charge on nitrogen bonded to a phosphorus atom and the strongest capability of forming hydrogen bonding with [CH][AA]. The introduced nitrogen and phosphorus elements not only increase the hydrogen bonding density in m-lignin/[CH][AA] but also enhance the polarity of the m-lignin, both of which facilitate a strong adhesion of lubricant on a metal surface and thus promote lubrication. A larger fraction of heteroatom groups in m-lignin contributes to a better lubrication property of these lubricants
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| 22. |
- Wu, Jian, et al.
(författare)
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CuO nanosheets produced in graphene oxide solution : An excellent anti-wear additive for self-lubricating polymer composites
- 2018
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Ingår i: Composites Science And Technology. - : Elsevier. - 0266-3538 .- 1879-1050. ; 162, s. 86-92
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Tidskriftsartikel (refereegranskat)abstract
- In the present work, graphene oxide is used as template to produce CuO nanosheets, which solves aggregation and dispersion problems of CuO nanosheets resulting in improved lubricating performance. SEM and AFM studies show that CuO nanosheets are present in fusiform flake shape with a thickness, width and length of around 13, 400 and 1000 nm, respectively. CuO nanosheets were added to the carbon fibers reinforced Polytetrafluoroethylene (CF/PTFE) to study their lubricating performance. It is interesting, from fractured surfaces of composites, to find that CuO nanosheets enhance the interface properties between carbon fibers and PTFE. The wear resistance property of CF/PTFE is remarkably improved after filling CuO nanosheets. For example, the wear rate is reduced by 51% after filling 1.5 wt % CuO nanosheets. The wear resistance improvement effect of CuO nanosheets is much better than that of commercial CuO nanogranules and CuO nanorods. Worn surfaces and counter-surfaces studying indicates that CuO nanosheets can not only prevent the rubbed-off of PTFE or the detachment of CF, but also improve the properties of transfer films, which greatly reduce the adhesive wear and abrasive wear.
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| 23. |
- Wu, Jian, 1988-, et al.
(författare)
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Halogen-free ionic liquids as excellent lubricants for PEEK-stainless steel contacts at elevated temperatures
- 2016
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 104, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Advanced polymers sliding against steel under ionic liquids (ILs) has great potential applications. However, halogen-containing ILs (h-ILs) often induce high corrosive wear to steel. In this work, halogen-free ILs (hf-ILs) were used as neat lubricants to investigate the performance of poly(ether-ether-ketone)-AISI304 stainless steel (PEEK-304ss) contacts at elevated temperatures. The results indicate that hf-ILs with short alkyl chains show excellent anti-corrosion and antiwear properties. The wear rates of 304ss lubricated by hf-ILs at 160 °C are 3–71% of those by h-ILs. The friction coefficients of PEEK-304ss lubricated by hf-ILs are just 13–33% of those by h-ILs. The excellent performance of hf-ILs can be attributed to the reason that hf-ILs will not generate any halogen containing acid during the test
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| 24. |
- Wu, Jian, et al.
(författare)
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High load capacity with Ionic liquid-lubricated tribological system
- 2016
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Ingår i: Tribology International. - : Elsevier BV. - 0301-679X .- 1879-2464. ; 94, s. 315-322
-
Tidskriftsartikel (refereegranskat)abstract
- Engineering polymers with high glass transition temperature have been widely used in dynamic friction systems by oil or solid lubrication. However, in high-load systems, oil lubrication is less efficient due to the viscosity decrease at higher temperatures induced by friction heat. [Bmim][PF6] ionic liquid was used and compared with traditional L-HM46 oil and solid PTFE. Taking advantage of high [Bmim][PF6] viscosity, strong steel-[Bmim][PF6] but poor PEEK-[Bmim][PF6] interaction, the [Bmim][PF6] lubricated PEEK/steel slide falls in hydrodynamic lubrication and elastohydrodynamic lubrication region under 150–1500 N. While the oil and PTFE both failed to lubricate under 800 N.
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| 25. |
- Wu, Jian, 1988-, et al.
(författare)
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Hollow IF-MoS2/r-GO Nanocomposite Filled Polyimide Coating with Improved Mechanical, Thermal and Tribological Properties
- 2021
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Ingår i: Coatings. - : MDPI. - 2079-6412. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- Polyimide (PI) is one of the most excellent polymers for coating. However, the high friction coefficient and the high wear rate of pure PI limit its further applications. In this work, the hollow inorganic fullerene-like MoS2/reduced graphene oxide (HIF-MoS2/r-GO) nanocomposite filled PI coating is prepared by in situ polymerization. Reinforcement in mechanical strength and thermal stability is realized on the PI composite coating with incorporation of HIF-MoS2/r-GO, which performs better than carbon nanofiber (CNF). Reduced elastic modulus and hardness of HIF-MoS2/r-GO/PI coating is increased by 8.3% and 4.8%, respectively. The addition of HIF-MoS2/r-GO also results in 24% higher residual mass at 800 °C than CNF. Tribological study indicates that, HIF-MoS2/r-GO/PI achieves a wear rate reduction of 79% compared with pure PI under dry sliding condition, which is much more effective than other nanofillers including CNF, r-GO nanosheets and MoS2 nanoparticles. Under ionic liquid-lubricated condition, the presence of HIF-MoS2/r-GO in PI results in a 30% reduction in wear rate and 10% reduction in friction coefficient as compared to pure PI. It is thought that the HIF-MoS2/r-GO in PI can be slowly released to the frictional interface and form a protective film during sliding, in this way the aggregation problem is successfully solved.
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| 26. |
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| 27. |
- Wu, Jian, et al.
(författare)
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Poly(alkylimidazolium bis(trifluoromethylsulfonyl) imide)-Based Polymerized Ionic Liquids : A Potential High-Performance Lubricating Grease
- 2019
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Ingår i: Advanced Materials Interfaces. - : John Wiley & Sons. - 2196-7350. ; 6:5
-
Tidskriftsartikel (refereegranskat)abstract
- Polymers prepared from ionic liquids are widely called polymerized ionic liquids (PILs). Compared to monocationic and dicationic ILs, PILs have higher molecular weights, charge, and greater intermolecular interactions, which make PILs have a higher possibility to generate better lubricity. PILs of poly‐alkylimidazolium bis(trifluoromethylsulfonyl)imide (PImC6NTf2) is studied herein. Dicationic ILs of 1,1′‐(pentane‐1,5‐diyl)‐bis(3‐butylimidazolium) bis(trifluoromethylsulfonyl)imide (BIm5‐(NTf2)2) is used as additive to decrease the crystallization temperature of PImC6NTf2. Lubricity of PImC6NTf2 and PImC6NTf2+BIm5‐(NTf2)2, as well as BIm5‐(NTf2)2 for comparison is evaluated under severe conditions, i.e., 3.0 to 3.5 GPa and 200 °C. The rheological study suggests that PImC6NTf2 can be classified into grease. Tribological test results show that PImC6NTf2 has much better antiwear property than BIm5‐(NTf2)2, especially at 3.5 GPa. Adding 4% BIm5‐(NTf2)2 to PImC6NTf2 is able to reduce friction under high pressure. At 200 °C, PImC6NTf2 exhibits excellent lubricity. The mixture of 96%PImC6NTf2+4%BIm5‐(NTf2)2 shows even better antiwear property than neat PImC6NTf2 and exhibits the highest friction reducing property among the ILs at 200 °C. It is speculated that the robust strength of PILs and strong adhesion between PILs and solids are key factors in achieving the excellent antiwear property.
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| 28. |
- Wu, Jian, et al.
(författare)
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Poly(ionic liquid)s as lubricant additives with insight into adsorption-lubrication relationship
- 2022
-
Ingår i: Tribology International. - : Elsevier. - 0301-679X .- 1879-2464. ; 165
-
Tidskriftsartikel (refereegranskat)abstract
- Ionic liquids (ILs) are very potential lubricant additives for their strong adsorption and tribochemical reactions at the interface. In this work, poly(ionic liquid) of PImC6NTf2 is used as lubricant additive in base oil of PEG, which can reduce the wear volume by around 65 times under 2.5 GPa. The lubricity is much more advantageous than the geminal dicationic IL of BIm5-(NTf2)2. The adsorption strength of lubricants is studied by employing the microcalorimeter to evaluate the adsorption heat, AFM to test the adhesion force, and molecular dynamics simulation to calculate the interfacial binding energy. As a result, the adsorption strength of PImC6NTf2 is obviously higher than BIm5-(NTf2)2, and the lubricity is strongly dependent on the adsorption strength of ILs.
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| 29. |
- Wu, Jian, et al.
(författare)
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Synthesis of hollow fullerene-like molybdenum disulfide/reduced graphene oxide nanocomposites with excellent lubricating properties
- 2018
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Ingår i: Carbon. - : Elsevier. - 0008-6223 .- 1873-3891. ; 134, s. 423-430
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, bubble-on-plate structure is realized on hollow IF-MoS2/reduced graphene oxide (HIF-MoS2/RGO) nanocomposites. HIF-MoS2 nanocages templated with the generated ammonia (NH3) are connected to RGO through the interlayered MoS2. The as-prepared HIF-MoS2/RGO is added into an ionic grease to study the tribological behavior of HIF-MoS2/RGO. For comparison, commercial grade MoS2 nanoparticles, single RGO or HIF-MoS2 or their physical mixture are also studied. Tribological results show that, compared with other additives, HIF-MoS2/RGO nanocomposites have the best anti-wear properties especially under higher load of 3.0 GPa. The wear reduction of HIF-MoS2/RGO reinforced grease under 2.5 GPa and 3.0 GPa reached 67% and 96%, respectively. In addition, HIF-MoS2/RGO reinforced grease achieves much lower and stable friction coefficient (0.079, the value of neat grease is 0.098) under 3.0 GPa. HIF-MoS2/RGO reinforced grease maintains very low friction coefficient and wear up to 4.1 GPa, while the normal MoS2 and RGO show high wear at the pressure up to 3.0 GPa. It is proposed that HIF-MoS2 nanocages on RGO act as rolling balls during friction resulting in better separation of steels.
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| 30. |
- Wu, Jian, et al.
(författare)
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Turning the solubility and lubricity of ionic liquids by absorbing CO2
- 2018
-
Ingår i: Tribology International. - : Elsevier. - 0301-679X .- 1879-2464. ; 121, s. 223-230
-
Tidskriftsartikel (refereegranskat)abstract
- Ionic liquids (ILs) attract high interest as lubricants or lubricant additives due to their special physicochemical characteristics. CO2 is a widely distributed gas. In many situations, its influence on lubricants cannot be avoided. In this work, three ILs are synthesized from choline and amino acids of glycine, l-proline and lysine, respectively. The influence of CO2 absorption on their solubility and lubricity is investigated. In general, it is interesting to find that the solubility is decreased and their lubricity is obviously improved after absorbing CO2, which is strongly related to their functional group (amino group) interactions with CO2. The formation of carbamate groups greatly increases the viscosity resulting in less solid contacts, and strengthens the interfacial adhesion between ILs and solids.
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| 31. |
- Wu, Nanhua, et al.
(författare)
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Confinement Phenomenon Effect on the CO2 Absorption Working Capacity in Ionic Liquids Immobilized into Porous Solid Supports
- 2017
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 33:42, s. 11719-11726
-
Tidskriftsartikel (refereegranskat)abstract
- In this work, the CO2 absorption working capacity and solubility in the ionic liquids immobilized into porous solid materials (substrates) was studied both experimentally and theoretically. The CO2 absorption working capacity in the immobilized ionic liquids was measured experimentally. It was found that the CO2 absorption working capacity and solubility increased up to 10 times compared to that in the bulk ionic liquids when the film thickness is nearly 2.5 nm in the [HMIm][NTf2] immobilized into the P25. Meanwhile, a new model was proposed to describe the Gibbs free energy of CO2 in the immobilized ionic liquids, and both macro- and micro-analyses of the CO2 solubility in the confined ionic liquids were conducted. The theoretical investigations reveal that the substrate has a crucial effect on the gas solubility in the ionic liquid immobilized into the substrates, and the model performance was approved with the consideration of substrate effect.
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| 32. |
- Wu, Nanhua, et al.
(författare)
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Generalized Gibbs free energy of confined nanoparticles
- 2017
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Ingår i: AIChE Journal. - : John Wiley & Sons. - 0001-1541 .- 1547-5905. ; 63:10, s. 4595-4603
-
Tidskriftsartikel (refereegranskat)abstract
- The nanoparticles generally show abnormal properties compared to those in the bulk phase, and they exhibit significant potential in various applications such as catalysis and energy conversion. However, the theoretical work for describing the properties of nanoparticles is limited with poor prediction capacity. In this work, the Gibbs free energy was studied, from both macroscope and microscope, predictive models were proposed to study the thermodynamic properties of nanoparticles with a generalized description of the Gibbs free energy considering the effects of surface-energy and the substrate contacted. The proposed model from the microscope was based on the corresponding states theory to describe the effect of the substrate on the Gibbs free energy of nanoparticles, in which the molecular parameter with a generalized constant was obtained from the melting point of metals due to sufficient experimental information. The comparison with the new measured experimental results proves the reliability of the model prediction
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| 33. |
- Wu, Na, et al.
(författare)
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Interaction between proteins and roughness-regulated TiO2 nanotube arrays
- 2020
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Ingår i: Huagong Xuebao/CIESC Journal. - : Materials China. - 0438-1157. ; 71:2, s. 831-842
-
Tidskriftsartikel (refereegranskat)abstract
- A series of TiO2 nanotube arrays (TNAs) with different diameters and roughness were prepared by electrochemical anodization method by changing the fluoride ion concentration [0.4%, 0.3%, 0.2%(mass)] and applied voltage(15, 25, 35, 45 V). The scanning electron microscopy (FESEM) and atomic force microscopy (AFM) results showed that the wall thickness of the prepared TNAs increased and the roughness decreased with the decrease of fluoride ion concentration in the electrolyte. The effects of surface roughness and diameter on the surface mechanical properties of TNAs and the interaction of Cytochrome C (Cyt C) were studied by AFM characterization. The results show that the adhesion is proportional to the contact area. With the increase of the diameter of the TNAs, the wall thickness decreases, the effective contact area between TNAs and Cyt C increases first and then decreases, and the forces of Cyt C with TNAs also increase first and then decrease. The roughness decreases when the diameter was fixed, the effective area of TNAs increases, and the interaction force also increases. It can be seen that the surface roughness and effective contact area of TNAs can be effectively controlled by changing the fluoride ion concentration of the electrolyte, which is further beneficial to promoting interaction with protein molecules.
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| 34. |
- Wu, Nanhua, et al.
(författare)
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Mesoscience in Supported Nano-metal Catalysts based on Molecular Thermodynamic Modeling : A Mini Review and Perspective
- 2021
-
Ingår i: Chemical Engineering Science. - : Elsevier. - 0009-2509 .- 1873-4405. ; 229
-
Forskningsöversikt (refereegranskat)abstract
- Supported nano-metal catalysts are widely used in industrial processes. There is a trade-off between the activity and stability from mesoscale, which can be effectively tackled with the principle of compromise in competition (mechanisms A and B). To apply mesoscience methodology in this specific area, this work summarized research progress, where direct H2O2 synthesis was chosen as a typical case to identify and represent mechanism A (activity) and mechanism B (stability). It was found that mechanism A has been widely studied, while mechanism B still cannot reflect explosion. Subsequently, reaction heat and fusion enthalpy were proposed to represent mechanism B in this work, and the molecular thermodynamic model was identified as an effective tool for the study. A corresponding framework for mechanism B was constructed and the progress in developing the model for this particular purpose was provided. Finally, perspectives were discussed based on the linear non-equilibrium thermodynamics.
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| 35. |
- Wu, Nanhua, et al.
(författare)
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Thermodynamic analysis and modification of Gibbs–Thomson equation for melting point depression of metal nanoparticles
- 2021
-
Ingår i: Chinese Journal of Chemical Engineering. - : Elsevier. - 1004-9541 .- 2210-321X. ; 31, s. 198-205
-
Tidskriftsartikel (refereegranskat)abstract
- Abnormal melting point depression of metal nanoparticles often occurs in heterogeneous catalytic reactions, which leads to a reduction in the stability of reactive nanoclusters. To study this abnormal phenomenon, the original and surface-energy modified Gibbs–Thomson equations were analyzed in this work and further modified by considering the effect of the substrate. The results revealed that the original Gibbs–Thomson equation was not suitable for the particles with radii smaller than 10 nm. Moreover, the performance of the surface-energy modified Gibbs–Thomson equation was improved, and the deviation was reduced to (-350 ∼ 100) K, although further modification of the equation by considering the interfacial effect was necessary for the small particles (r < 5 nm). The new model with the interfacial effect improved the model performance with a deviation of approximately -50 to 20 K, where the interfacial effect can be predicted quantitatively from the thermodynamic properties of the metal and substrate. Additionally, the micro-wetting parameter αw can be used to qualitatively study the overall impact of the substrate on the melting point depression.
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| 36. |
- Wu, Wei, et al.
(författare)
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Roles of Mitogen-Activated Protein Kinases in the Modulation of Endothelial Cell Function Following Thermal Injury
- 2011
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Ingår i: Shock. - : Biomedical Press. - 1073-2322 .- 1540-0514. ; 35:6, s. 618-625
-
Tidskriftsartikel (refereegranskat)abstract
- Several mitogen-activated protein kinases (MAPKs) are activated during thermal injury, and the p38 MAPK is specifically involved in endothelial cell (EC) actin and myosin rearrangement (stress-fiber formation) with ensuing cellular contraction and enhanced vessel permeability. Inhibition of p38 MAPK and extracellular signal-related kinase MAPK by their inhibitors SB203580 and PD98059, respectively, significantly reduces burn serum-induced EC stress-fiber formation, whereas SB203580 also inhibits burn serum-induced EC tight-junction damage and thereby general blood vessel hyperpermeability. The JNK MAPK inhibitor, SP600125, on the contrary, influences neither stress-fiber formation nor EC tight-junction damage. Extracellular signal-related kinase MAPK inhibition significantly decreases burn serum-induced Monocyte chemotactic protein-1 (MCP-1) release, whereas SB203580 and SP600125 have only limited such effects. Western blotting, real-time reverse transcriptase-polymerase chain reaction, and confocal laser scanning microscopy proved that SP600125 significantly inhibits burn serum-induced intercellular adhesion molecule 1 expression, whereas SB203580 depresses the expression of P selectin. In vivo studies, using the dominant negative adenoviral approach of MAPK kinase 3b and MAPK kinase 6b to block p38 MAPKs, and MKK4 and MKK7 to block JNK MAPKs, show that the latter MAPKs are involved in the regulation of P selectin and intercellular adhesion molecule 1 expression, respectively, following thermal injury. Taken together, the results suggest that several MAPKs play important, although different, roles in general EC alterations following burn injuries.
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| 37. |
- Wu, Xiaohua, et al.
(författare)
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Online Adaptive Model Identification and State of Charge Estimation for Vehicle-Level Battery Packs
- 2024
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Ingår i: IEEE Transactions on Transportation Electrification. - 2332-7782. ; 10:1, s. 596-607
-
Tidskriftsartikel (refereegranskat)abstract
- Accurate state of charge (SOC) estimation of traction batteries plays a crucial role in energy and safety management for electric vehicles. Existing studies focus primarily on cell battery SOC estimation. However, numerical instability and divergence problems might occur for a large-size lithium-ion battery pack consisting of many cells. This paper proposes a high-performance online model identification and SOC estimation method based on an adaptive square root unscented Kalman filter (ASRUKF) and an improved forgetting factor recursive least squares (IFFRLS) for vehicle-level traction battery packs. The model parameters are identified online through the IFFRLS, where the conventional method might encounter numerical stability problems. By updating the square root of the covariance matrix, the divergence problem in the traditional unscented Kalman filter is solved in the ASRUKF algorithm, where the positive semi-definiteness of the covariance matrix is guaranteed. Combined with the adaptive noise covariance matched filtering algorithm and real-time compensation of system error, the proposed method solves the problem of ever-degrading estimation accuracy in the presence of time-varying noise with unknown statistical characteristics. Using a 66.2-kWh vehicle battery pack, we experimentally verified that the proposed algorithm could achieve high estimation accuracy with guaranteed numerical stability. The maximum error of SOC estimation can be bounded by 1%, and the root-mean-square error is as low as 0.47% under real-world vehicle operating conditions.
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| 38. |
- Yin, Xiang, et al.
(författare)
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Right Way of Using Graphene Oxide Additives for Water-Lubricated PEEK : Adding in Polymer or Water?
- 2018
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Ingår i: Tribology letters. - : Springer. - 1023-8883 .- 1573-2711. ; 66:3
-
Tidskriftsartikel (refereegranskat)abstract
- Water-lubricated polymer is attracting more and more interest from the industry. Adding nanoparticles is considered to be an effective way to improve the tribological performance. In this work, water-lubricated Polyetheretherketone (PEEK)-steel contacts were employed as the objects of study. A careful comparative study was made by investigating the effect of adding graphene oxide (GO) into water or into PEEK. Results show that adding GO into water can significantly reduce the wear and friction coefficient of pure PEEK, which is much more effective than adding GO into PEEK. Under the lubrication of GO aqueous dispersion, the wear of PEEK remains very low even under a harsh condition where the pressure reaches 50 MPa and the linear sliding speed is 0.7 m/s. Neat PEEK and GO/PEEK composites in pure water exhibit serious wear under this harsh condition. The excellent lubricating properties of GO aqueous dispersion are attributed to GO nanosheets entering into solid contacts, which can not only form a protective layer on steel counterpart repairing the worn surface, but also strongly adhere to the PEEK matrix resulting in an in situ-formed GO coating and prevent the scratch by steel counterpart.
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| 39. |
- Zhou, Hongxu, et al.
(författare)
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Model optimization of a high-power commercial PEMFC system via an improved grey wolf optimization method
- 2024
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Ingår i: Fuel. - 0016-2361. ; 357:Part A
-
Tidskriftsartikel (refereegranskat)abstract
- Proton exchange membrane fuel cell (PEMFC) models are conventionally established with a set of parameters identified under steady-state operating conditions. However, such an approach is insufficient to accurately capture the dynamic characteristics of multi-parameter changes in real-world scenarios. This paper develops a semi-empirical model for a 110-kW commercial PEMFC system based on its dynamic operation data to remedy the defects. To improve the fitting accuracy of the semi-empirical PEMFC model, an improved grey wolf optimization (IGWO) algorithm is proposed for model parameter identification. The IGWO algorithm adopts chaotic mapping to optimize the initial population distribution, and a random walk strategy is incorporated to boost the local search ability of the traditional grey wolf optimization (GWO) algorithm. The effectiveness of this IGWO algorithm in optimizing the semi-empirical model is experimentally verified on the 110-kW PEMFC system under highly dynamic operating conditions. Results show that the proposed IGWO algorithm can effectively identify the semi-empirical model’s parameters, establishing a stable and robust model that outperforms those based on traditional metaheuristic algorithms such as GWO, particle swarm optimization, and genetic algorithm. The demonstrated improvement renders it as better suited for optimizing PEMFC semi-empirical models under real-world operating conditions.
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| 40. |
- Zhou, Qilong, et al.
(författare)
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Versatile Ionic Gel Driven by Dual Hydrogen Bond Networks : Toward Advanced Lubrication And Self-Healing
- 2021
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Ingår i: ACS Applied Polymer Materials. - : American Chemical Society (ACS). - 2637-6105. ; 3:11, s. 5932-5941
-
Tidskriftsartikel (refereegranskat)abstract
- From one to more, the same raw materials giving rise to multifarious products is one of the goals of researchers to pursue industrial efficiency. Herein, we designed a formula (controlling the content of the matrix) to prepare two functional ionic gels, integrating the excellent lubrication, thermal conductivity, and self-healing ability to meet different industrial demands of the lubrication and biomedical fields. Deep eutectic solvents (DESs) of urea/choline chloride (UCC) and glycerol/choline chloride (GCC) were locked in polyacrylamide (PAM) ionic gel formed by acrylamide (AM) and a photoinitiator by freer-adical polymerization. The unique dual hydrogen bond network in the ionic gel causes the material to exhibit a low wear rate, which can effectively reduce the wear of metal contact. With the addition of PAM, the ionic gel has excellent mechanical strength and good recovery performance. Unexpectedly, this dense hydrogen bond network enhances thermal conductivity by optimizing phonon and electron transfer. The versatile ionic gel has a good application prospect as a substitute for industrial lubricants and medical device materials.
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| 41. |
- Zhou, Yue, et al.
(författare)
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Stabilized and Controlled Release of Radicals within Copper Formate-Based Nanozymes for Biosensing
- 2023
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 15:37, s. 43431-43440
-
Tidskriftsartikel (refereegranskat)abstract
- Fenton-like radical processes are widely utilized to explain catalytic mechanisms of peroxidase-like nanozymes, which exhibit remarkable catalytic activity, cost-effectiveness, and stability. However, there is still a need for a comprehensive understanding of the formation, stabilization, and transformation of such radicals. Herein, a copper formate-based nanozyme (Cuf-TMB) was fabricated via a pre-catalytic strategy under ambient conditions. The as-prepared nanozyme shows comparable catalytic activity (K-m, 1.02 x 10(-5) mM(-1); K-cat, 3.09 x 10(-2) s(-1)) and kinetics to those of natural peroxidase toward H2O2 decomposition. This is attributed to the feasible oxidation by *OH species via the *O intermediate, as indicated by density functional theory calculations. The key .OH radicals were detected to be stable for over 52 days and can be released in a controlled manner during the catalytic process via in situ electron spin-resonance spectroscopy measurements. Based on the understanding, an ultrasensitive biosensing platform was constructed for the sensitive monitoring of biochemical indicators in clinic settings.
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