| 1. |
- Li, P. F., et al.
(författare)
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Stable transmission of low energy electrons in glass tube with outer surface grounded conductively shielding
- 2022
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Ingår i: Acta Physica Sinica. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 71:7
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Tidskriftsartikel (refereegranskat)abstract
- The electron microbeam is useful for modifying certain fragments of biomolecule. It is successful to applythe guiding effect to making the microbeam of positively charged particles by using single glass capillary.However, the mechanism for the electron transport through insulating capillaries is unclear. Meanwhile,previous researches show that there are oscillations of the transmission intensity of electrons with time in theglass capillaries with outer serface having no grounded conductive shielding, So, the application of glasscapillary to making the microbeam of electrons is limited. In this paper, the transmission of 1.5 and 0.9 keV electrons through the glass capillary without/with thegrounded conductive-coated outer surface are investigated, respectively. This study aims to understand themechanism for low energy electron transport in the glass capillaries, and find the conditions for the steadytransport of the electrons. Two-dimensional angular distribution of the transported electrons and its timeevolution are measured. It is found that the intensity of the transported electrons with the incident energythrough the glass capillaries for the glass capillaries without and with the grounded conductive-coated outersurface show the typical geometrical transmission characteristics. The time evolution of the 1.5- keV electrontransport presents an extremely complex variation for the glass capillary without the grounded conductive-coated outer surface. The intensity first falls, then rises and finally oscillates around a certain mean value.Correspondingly, the angular distribution center experiences moving towards positive-negative-settlement. Incomparison, the charge-up process of the 0.9 keV electron transport through the glass capillary with thegrounded conductive-coated outer surface shows a relatively simple behavior. At first, the intensity declines rapidly with time. Then, it slowly rises till a certain value and stays steady subsequently. The angulardistribution of transported electrons follows the intensity distribution in general, but with some delay. It quicklymoves to negative direction then comes back to positive direction. Finally, it regresses extremely slowly andends up around the tilt angle. To better understand the physics behind the observed phenomena, the simulationfor the interaction of the electrons with SiO2 material is performed to obtain the possible deposited chargedistribution by the CASINO code. Based on the analysis of the experimental results and the simulated chargedeposition, the conditions for stabilizing the electron transport through glass capillary arepresented.
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| 2. |
- Wang, Xiaoyu, et al.
(författare)
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Guest Editorial: Modeling and Simulation Methods for Analysis and Design of Advanced Energy Conversion Systems
- 2020
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Ingår i: IEEE Transactions on Energy Conversion. - 1558-0059 .- 0885-8969. ; 35:1, s. 309-311
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The papers in this special section examine modeling and simulation methods for the analysis and design of advanced energy conversion systems. Energy conversion lies aEnergyveral fronts including materials, conversion methods, power electronics, and controls have created new opportunities for efficient energy conversion from both the conventional and new sources of energy. Our urgent need to solve many critical problems with regards to the sustainability and security of our energy system as well as the ever-increasing environmental challenges facing humanity have further spurred unprecedented opportunities for creation of innovative solutions to address these challenges.
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| 3. |
- Liberman, Michael, et al.
(författare)
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Influence of chemical kinetics on spontaneous waves and detonation initiation in highly reactive and low reactive mixtures
- 2019
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Ingår i: Combustion theory and modelling. - : Informa UK Limited. - 1364-7830 .- 1741-3559. ; 23:3, s. 467-495
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the mechanisms of explosions is important for minimising devastating hazards. Due to the complexity of real chemistry, a single-step reaction mechanism is usually used for theoretical and numerical studies. The purpose of this study is to look more deeply into the influence of chemistry on detonation initiated by a spontaneous wave. The results of high-resolution simulations performed for one-step models are compared with simulations for detailed chemical models for highly reactive and low reactive mixtures. The calculated induction times for H-2/air and for CH4/air are validated against experimental measurements for a wide range of temperatures and pressures. It is found that the requirements in terms of temperature and size of the hot spots, which can produce a spontaneous wave capable to initiate detonation, are quantitatively and qualitatively different for one-step models compared to detailed chemical models. The time and locations when the exothermic reaction affects the coupling between the pressure wave and spontaneous wave are considerably different for a one-step and detailed models. The temperature gradients capable to produce detonation and the corresponding size of hot spots are much shallower and, correspondingly, larger than those predicted using one-step models. The impact of the detailed chemical model is particularly pronounced for the methane-air mixture. In this case, not only the hot spot size is much greater than that predicted by a one-step model, but even at the elevated pressure, the initiation of detonation by a temperature gradient is possible only if the temperature outside the gradient is rather high, so that can ignite a thermal explosion. The obtained results suggest that the one-step models do not reproduce correctly the transient and ignition processes, so that interpretation of the simulations performed using a one-step model for understanding mechanisms of flame acceleration, DDT and the origin of explosions must be considered with great caution.
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| 4. |
- Cheng, Hao, et al.
(författare)
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Nanoparticles with aggregation-induced emission for monitoring long time cell membrane interactions
- 2013
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Ingår i: Progress In Electromagnetics Research. - 1070-4698 .- 1559-8985. ; 140, s. 313-325
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Tidskriftsartikel (refereegranskat)abstract
- We perform the long time monitoring of nanoparticle-cell membrane interaction with high spatial and temporal resolution. The 2, 3-bis(4-(pheny1(4-(1, 2, 2-triphenylvinyl) phenyl)amino)phenyl) fumaronitrile (TPE-TPA-FN) is doped in organically modified silica (ORMOSIL) to be a biocompatible nanoprobe, which displays an aggregation-induced emission (ATE) effect. Photobleaching resistance of this synthesized nanoparticle is tested and compared with its similar counterpart, which proves its superiority and capability of long term fluorescence emission. We utilize the objective-based total internal reflection microscopy combined with the living cell incubation platform to investigate the cell uptake process of this nanoparticle in real time.
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| 5. |
- Wang, Cheng, et al.
(författare)
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Influence of chemical kinetics on detonation initiating by temperature gradients in methane/air
- 2018
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180 .- 1556-2921. ; 197, s. 400-415
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Tidskriftsartikel (refereegranskat)abstract
- Different simplified and detailed chemical models and their impact on simulations of combustion regimes initiating by the initial temperature gradient in methane/air mixtures are studied. The limits of the regimes of reaction wave propagation depend upon the spontaneous wave speed and the characteristic velocities of the problem. The present study mainly focus to identify conditions required for the development a detonation and to compare the difference between simplified chemical models and detailed chemistry. It is shown that a widely used simplified chemical schemes, such as one-step, two-step and other simplified models, do not reproduce correctly the ignition process in methane/air mixtures. The ignition delay times calculated using simplified models are in orders of magnitude shorter than the ignition delay times calculated using detailed chemical models and measured experimentally. This results in considerably different times when the exothermic reaction affects significantly the ignition, evolution, and coupling of the spontaneous reaction wave and pressure waves. We show that the temperature gradient capable to trigger detonation calculated using detailed chemical models is much shallower (the size of the hot spot is much larger) than that, predicted by simulations with simplified chemical models. These findings suggest that the scenario leading to the deflagration to detonation transition (DDT) may depend greatly on the chemical model used in simulations and that the Zel'dovich gradient mechanism is not necessary a universal mechanism triggering DDT. The obtained results indicate that the conclusions derived from the simulations of DDT with simplified chemical models should be viewed with great caution.
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| 6. |
- Zhan, Qiuqiang, et al.
(författare)
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Optimization of Optical Excitation of Upconversion Nanoparticles for Rapid Microscopy and Deeper Tissue Imaging with Higher Quantum Yield
- 2013
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Ingår i: Theranostics. - : Ivyspring International Publisher. - 1838-7640. ; 3:5, s. 306-316
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Tidskriftsartikel (refereegranskat)abstract
- Relatively low quantum yield (QY), time-consuming scanning and strong absorption of light in tissue are some of the issues present in the development of upconversion nanoparticles (UCNPs) for biomedical applications. In this paper we systematically optimize several aspects of optical excitation of UCNPs to improve their applicability in bioimaging and biotherapy. A novel multi-photon evanescent wave (EW) excitation modality is proposed for UCNP-based microscopy. The scanning-free, ultrahigh contrast and high spatiotemporal resolution method could simultaneously track a few particles in a large area with a speed of up to 350 frames per second. The HeLa cancer cell membrane imaging was successfully performed using NaYF4: 20% Yb3+/2% Er3+ targeting nanoparticles. Studies with different tissues were made to illustrate the impact of optical property parameters on the deep imaging ability of 920-nm band excitation. In the experiments a semiconductor laser with a 920 nm wavelength was used to excite UCNPs in tissue phantom at five depths. Our experimental and computational results have shown that in UCNP-based diffusion optical imaging with 920-nm laser excitation could lead to larger imaging depth range compared to traditional 974-nm excitation in a wide dynamic range of tissue species. As the QY is power density dependent, a pulsed laser is proposed to improve the QY of UCNPs. This proposal is promising in drastically increasing the imaging depth and efficiency of photodynamic therapy.
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| 7. |
- Zhang, Yingfeng, et al.
(författare)
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Game theory based real-time shop floor scheduling strategy and method for cloud manufacturing
- 2017
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Ingår i: International Journal of Intelligent Systems. - : John Wiley & Sons. - 0884-8173 .- 1098-111X. ; 32:4, s. 437-463
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Tidskriftsartikel (refereegranskat)abstract
- With the rapid advancement and widespread application of information and sensor technologies in manufacturing shop floor, the typical challenges that cloud manufacturing is facing are the lack of real‐time, accurate, and value‐added manufacturing information, the efficient shop floor scheduling strategy, and the method based on the real‐time data. To achieve the real‐time data‐driven optimization decision, a dynamic optimization model for flexible job shop scheduling based on game theory is put forward to provide a new real‐time scheduling strategy and method. Contrast to the traditional scheduling strategy, each machine is an active entity that will request the processing tasks. Then, the processing tasks will be assigned to the optimal machines according to their real‐time status by using game theory. The key technologies such as game theory mathematical model construction, Nash equilibrium solution, and optimization strategy for process tasks are designed and developed to implement the dynamic optimization model. A case study is presented to demonstrate the efficiency of the proposed strategy and method, and real‐time scheduling for four kinds of exceptions is also discussed.
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| 8. |
- Ding, Shaozhen, et al.
(författare)
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novoPathFinder: a webserver of designing novel-pathway with integrating GEM-model
- 2020
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Ingår i: Nucleic Acids Research. - : Oxford University Press (OUP). - 0305-1048 .- 1362-4962. ; 48:W1, s. W477-W487
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Tidskriftsartikel (refereegranskat)abstract
- To increase the number of value-added chemicals that can be produced by metabolic engineering and synthetic biology, constructing metabolic space with novel reactions/pathways is crucial. However, with the large number of reactions that existed in the metabolic space and complicated metabolisms within hosts, identifying novel pathways linking two molecules or heterologous pathways when engineering a host to produce a target molecule is an arduous task. Hence, we built a user-friendly web server, novoPathFinder, which has several features: (i) enumerate novel pathways between two specified molecules without considering hosts; (ii) construct heterologous pathways with known or putative reactions for producing target molecule within Escherichia coli or yeast without giving precursor; (iii) estimate novel pathways with considering several categories, including enzyme promiscuity, Synthetic Complex Score (SCScore) and LD50 of intermediates, overall stoichiometric conversions, pathway length, theoretical yields and thermodynamic feasibility. According to the results, novoPathFinder is more capable to recover experimentally validated pathways when comparing other rule-based web server tools. Besides, more efficient pathways with novel reactions could also be retrieved for further experimental exploration. novoPathFinder is available at http://design.rxnfinder.org/novopathfinder/.
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| 9. |
- Liberman, Michael, et al.
(författare)
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Dynamics of flames in tubes with no-slip walls and the mechanism of tulip flame formation1
- 2023
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Ingår i: Combustion Science and Technology. - : Informa UK Limited. - 0010-2202 .- 1563-521X. ; 195:7, s. 1637-1665
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Tidskriftsartikel (refereegranskat)abstract
- A hydrogen/air flame propagation and the development of tulip-shaped flame in 2D tubes of different aspect ratios with both closed ends and in a half-open rectangular channel were studied using high resolution direct numerical simulations of the fully compressible Navier–Stokes equations coupled with a detailed chemistry. Flame propagation in a 3D rectangular channel was studied using large eddy simulations and compared with the results of direct numerical simulations of flame propagation in a 2D rectangular channel with the same aspect ratio. It is shown that the interaction of the rarefaction wave generated by the flame at the deceleration stage with the “positive” flow of unburned gas generated by the flame at the previous accelerating stage leads to a significant decrease of the velocity of the unburned gas flow in the near field zone ahead of the flame front. As a result, the thickness of the boundary layer in the near-field zone ahead of the flame increases significantly, and the profile of the axial velocity of the unburned gas in the near-field zone ahead of the flame front takes the form of a tulip or an inverted tulip, which leads to corresponding changes in the velocities of different parts of the flame front, the flame front inversion, and the formation of a tulip-shaped flame.
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| 10. |
- Qian, Cheng, et al.
(författare)
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A cloud service platform integrating additive and subtractive manufacturing with high resource efficiency
- 2019
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Ingår i: Journal of Cleaner Production. - : ELSEVIER SCI LTD. - 0959-6526 .- 1879-1786. ; 241
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Tidskriftsartikel (refereegranskat)abstract
- Cloud manufacturing has been studied for years, yet commercial implementations are still limited. The recent advances in information technology have stimulated the free sharing of additive and subtractive manufacturing (A/SM) resources through cloud services. Currently, due to the lack of a general method to model manufacturing capabilities, as well as the absence of an open platform to integrate business and manufacturing processes, it is difficult to integrate A/SM resources within one platform efficiently and seamlessly. In this research, a service encapsulation model for A/SM resources was described using ontology modeling technique. A collaborative cloud platform integrating A/SM was designed that can provide optimal production plans considering time, cost, quality, and energy waste during manufacturing. The proposed platform and models were demonstrated by a prototype system and tested in a case study, which showed the integrated platform can increase the utilization rate of resources while reducing energy consumption. This research has provided a practical tool for virtualization, integration, and configuration of A/SM resource with high efficiency. (C) 2019 Elsevier Ltd. All rights reserved.
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