| 1. |
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| 2. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 3. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 4. |
- Zhaolong, Zhu, et al.
(författare)
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Cutting forces and chip formation revisited based on orthogonal cutting of Scots pine
- 2018
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Ingår i: Holzforschung. - : Walter de Gruyter. - 0018-3830 .- 1437-434X. ; 73:2, s. 131-138
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to understandbetter the cutting forces and chip formation of Scots pine(Pinus sylvestris L.) with different moisture contents (MCs)and machined in different cutting directions. To thatend, an orthogonal cutting experiment was designed,in which Scots pine was intermittently machined usinga tungsten carbide tool to produce chips. The cuttingforces were measured and the chip shapes were quantitativelydescribed. Four conclusions can be drawn: (1)with increasing MC, the average cutting forces initiallydecreased and then stabilized, while the angle betweenthe direction of the main and the resultant force continuouslydecreased. (2) The average cutting forces in the 90°–0° cutting direction were lower than the same forces inthe 90°–90° cutting direction. (3) During machining, thedynamic cutting forces fluctuated less in the 90°–0° case.However, the dynamic feeding forces showed a decreasingtrend in both the 90°–0° and the 90°–90° cases. (4) Theprocess applied produced granule chips and flow chips,while less curly flow chips with a higher radius of curvaturewere more easily produced from samples with highMCs in the 90°–0° cutting direction.
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| 5. |
- Zhu, Zhaolong, et al.
(författare)
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Built-up edge formation mechanisms in orthogonal cutting of wood-plastic composite
- 2022
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Ingår i: Wood Material Science & Engineering. - : Taylor & Francis. - 1748-0272 .- 1748-0280. ; 17:5, s. 388-396
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Tidskriftsartikel (refereegranskat)abstract
- This project aims to improve the machinability of wood-plastic composites by understanding chip and built-up edge formation, so as to help manufacturers optimize cutting performance and product quality. Chip formation and built-up edge were studied during orthogonal cutting of wood polyethylene composite with cemented carbide cutters under different conditions. During the orthogonal cutting process, segmental, ribbon, and element chips were generated. The cutting depth was found to have a great impact on the types of chips that formed. Additionally, a built-up edge was found during wood-plastic composite machining, with debris only attaching to the tool's rake face due to thermo-mechanical coupling. Such built-up edges hinder cutting stability and surface quality. Furthermore, variations in the accumulation of debris on the built-up edge corresponded to changes in cutting force and temperature. In fact, both cutting force and temperature proved to be inversely related to the rake angle and positively correlated to the cutting speed and depth. Therefore, to achieve better cutting stability and surface quality for wood-plastic composites, a larger rake angle and a reduced cutting depth are recommended because they reduce the accumulation of debris and the formation of built-up edge.
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| 6. |
- Zhu, Zhaolong, et al.
(författare)
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The Effects of Cutting Parameters and Tool Geometry on Cutting Forces and Tool Wear in Milling High-density Fiberboard with Ceramic Tools
- 2017
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Ingår i: The International Journal of Advanced Manufacturing Technology. - : Springer. - 0268-3768 .- 1433-3015. ; 91:9-12, s. 4033-4041
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the effects of cutting parametersand tool geometry on cutting forces and tool wear whenup-milling high-density fiberboard with alumina ceramiccutting tools were investigated. Under the condition ofthe same feed per tooth, average chip thickness, andclearance angle, the results shown are as follows: first,the tangential forces Ft and normal forces Fr at lowspeedcutting were higher than those at high-speed cutting,but increased slowly with the increase of cuttinglength and rake angle decrease. Second, increased cuttingspeed and decreased rake angle had a great effecton rake face wear. Third, the wear patterns of tool wearwere rake wear and flank wear, which included pull-outof grain, flaking, and chipping. The wear mechanismswere adhesive wear and abrasive wear. Finally, at lowspeedcutting, the cutting tools with bigger rake anglecan be selected to reduce the energy consumption ofmachine tools. The tools with smaller rake angle canbe used for high-speed cutting to improve tool lifeand productivity of processing.
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| 7. |
- Cao, Pingxiang, et al.
(författare)
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Effect of rake angle on cutting performance during machining of stone-plastic composite material with polycrystalline diamond cutters
- 2019
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Ingår i: Journal of Mechanical Science and Technology. - : Springer. - 1738-494X .- 1976-3824. ; 33:1, s. 351-356
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Tidskriftsartikel (refereegranskat)abstract
- This study investigates the effect of rake angle on cutting performance during machining of stone-plastic composite material with diamond cutters. To that end, an orthogonal cutting experiment was designed, in which stone-plastic composite material was planed by a polycrystalline diamond (PCD) cutter to produce chips. The features studied include cutting forces, cutting heat, chip formation and cutting quality. The conclusions are as follows: Firstly, increased rake angle causes frictional force and resulting force to decrease, promoting an increase in normal force. Secondly, during planing, cutting heat is primarily distributed in the chips, with less retained in the cutting edge, and the least retained in the machined surface. The temperatures of both cutting edge and chip decline with an increase in rake angle. Thirdly, as rake angle increases, chip morphology changes from segmental to curved and then to particle chips, with chip-breaking lengths first increasing and then decreasing. Finally, an increased rake angle leads a more stable cutting process and improved cutting quality. Therefore, with the precondition of blade strength, a diamond cutter with a larger rake angle can be used to machine stone-plastic composite to improve production quality by forming a smoother machined surface.
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| 8. |
- Guo, Xiaolei, et al.
(författare)
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Cutting forces and cutting quality in the up-milling of solid wood using ceramic cutting tools
- 2021
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Ingår i: The International Journal of Advanced Manufacturing Technology. - : Springer. - 0268-3768 .- 1433-3015. ; 114:5-6, s. 1575-1584
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Tidskriftsartikel (refereegranskat)abstract
- Although many studies have focused on the cutting performance of ceramic blades in processing different materials, few have reported on their application in wood processing. Thus, it is necessary to explore the cutting performance of ceramic tools in solid wood machining. The aims of this paper were to evaluate the cutting performance of Al2O3 and Si3N4 ceramic tools in the process of machining Manchurian ash (Fraxinus mandshurica Rupr.) and Chinese fir (Cunninghamia lanceolata) by means of analysing cutting force and surface roughness and to provide guidelines for factories for applying ceramic tools in the manufacture of solid wood furniture. Up-milling tests were conducted for each combination of cutting speed, tool material, and workpiece material, and each combination was replicated five times. Results showed that (1) cutting force and surface roughness decreased with increase of cutting speed and (2) cutting force and surface roughness resulting from using Al2O3 ceramic cutting tools were larger than those of Si3N4 ceramic cutting tools, especially when cutting Manchurian ash with its extractives. Overall, ceramic tools can be used in high-speed cutting of solid wood. Compared with Al2O3 ceramic cutting tools, Si3N4 ceramic cutting tools are more suitable for cutting solid wood, especially those with extractives. Si3N4 ceramic tools provided not only chemical stability, but improved final product quality.
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| 9. |
- Guo, Xiaolei, et al.
(författare)
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Machinability of wood fiber/polyethylene composite during orthogonal cutting
- 2021
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Ingår i: Wood Science and Technology. - : Springer. - 0043-7719 .- 1432-5225. ; 55:2, s. 521-534
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Tidskriftsartikel (refereegranskat)abstract
- Wood fiber/polyethylene composite (WFPEC) is composed of a natural wood fiber and a recyclable polyethylene plastic, which is normally used as an environmental protection composite material. However, better knowledge of chip formation and surface damage mechanism of WFPEC is essential to improve its machinability for extending exterior and interior applications. In this article, machinability of WFPEC was investigated by analyzing the disparity between cutting efficiency and surface quality through a group of orthogonal cutting experiments with change of cutting depth. The chip formation process was recorded by a high-speed camera system with 5000 frames per second. Surface topography was observed by a scanning electron microscope. The results showed that the chip morphology changed from continuous cutting governed by a continuous shearing process under the shallow cutting depth, to a discontinuous cutting governed by plastic fracture under the deep cutting depth ahead of the tool tip. Flattened matrix was the main form of surface topography caused by shallow cutting depth, while matrix-fiber tearing was caused by deep cutting depth. Pullout/fracture and debonding of fibers were related to the fiber orientation angle and the diameter of fiber bundles, but not to the cutting depth. Taken together, the toughness of the workpiece material in the cutting region decreased with the increase in cutting depth. To avoid matrix-fiber tearing, shallow cutting depth should be used during finishing to maintain surface quality. In contrast, pre-cutting can be performed with a deep cutting depth in order to improve the cutting efficiency.
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| 10. |
- Guo, Xiaolei, et al.
(författare)
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The cutting performance of Al2O3 and Si3N4 ceramic cutting tools in the milling plywood
- 2018
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Ingår i: Advances in Applied Ceramics. - : Taylor & Francis. - 1743-6753 .- 1743-6761. ; 117:1, s. 16-22
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Tidskriftsartikel (refereegranskat)abstract
- This research focuses on the cutting performance of Al2O3 and Si3N4 ceramic cutting tools in upmillingplywood, the results of which are as follows. First, whether the tool material is Al2O3 orSi3N4 ceramic, the cutting forces at low-speed cutting were less than those at high-speedcutting, and the machining quality at low-speed cutting was greater than that at high-speedcutting. Then, whether at low- or high-speed cutting, the cutting forces of Al2O3 cutting toolswere higher than those of Si3N4 cutting tools, and the machining quality of plywood milledby Al2O3 ceramic cutting tools was poorer than that milled by Si3N4 ceramic cutting tools.Finally, Si3N4 ceramic cutting tools were more suitable to machine the wooden productionswith much glue content than Al2O3 ceramic cutting tools for the better machined quality.
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| 11. |
- Jia, Zhenrong, et al.
(författare)
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Near-infrared absorbing acceptor with suppressed triplet exciton generation enabling high performance tandem organic solar cells
- 2023
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Ingår i: Nature Communications. - : NATURE PORTFOLIO. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Reducing the energy loss of sub-cells is critical for high performance tandem organic solar cells, while it is limited by the severe non-radiative voltage loss via the formation of non-emissive triplet excitons. Herein, we develop an ultra-narrow bandgap acceptor BTPSeV-4F through replacement of terminal thiophene by selenophene in the central fused ring of BTPSV-4F, for constructing efficient tandem organic solar cells. The selenophene substitution further decrease the optical bandgap of BTPSV-4F to 1.17 eV and suppress the formation of triplet exciton in the BTPSV-4F-based devices. The organic solar cells with BTPSeV-4F as acceptor demonstrate a higher power conversion efficiency of 14.2% with a record high short-circuit current density of 30.1 mA cm(-2) and low energy loss of 0.55 eV benefitted from the low non-radiative energy loss due to the suppression of triplet exciton formation. We also develop a high-performance medium bandgap acceptor O1-Br for front cells. By integrating the PM6:O1-Br based front cells with the PTB7-Th:BTPSeV-4F based rear cells, the tandem organic solar cell demonstrates a power conversion efficiency of 19%. The results indicate that the suppression of triplet excitons formation in the near-infrared-absorbing acceptor by molecular design is an effective way to improve the photovoltaic performance of the tandem organic solar cells. Reducing energy loss of sub-cells is critical for high performance tandem organic solar cells. Here, the authors design and synthesize an ultra-narrow bandgap acceptor through replacement of terminal thiophene by selenophene in the central fused ring, achieving efficiency of 19% for tandem cells.
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| 12. |
- Jiang, Shangsong, et al.
(författare)
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Cutting Force and Surface Roughness during Straight-Tooth Milling of Walnut Wood
- 2022
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Ingår i: Forests. - : MDPI. - 1999-4907. ; 13:12
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Tidskriftsartikel (refereegranskat)abstract
- Walnut (Juglans regia L.) is widely used in wood furnishings, and machinability is a key factor for improving product quality and enterprise benefits. This work focused on the influence of the rake angle, depth of cut, and cutting speed on the cutting force and machined surface roughness during the straight-tooth milling of walnut. On the basis of the experimental findings, a mathematical model was created using a response surface methodology to determine the relationship between the cutting force and the cutting conditions, as well as the relationship between the surface roughness and the cutting conditions. Variance analysis was used to study the significant contributions of the interactions of various factors and two-level interactions to the cutting force and surface roughness. The optimized combination of milling conditions, resulting in lowest cutting force and surface roughness, was determined to be a rake angle of 5°, a depth of cut of 0.6 mm, and a cutting speed of 45 m/s.
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| 13. |
- Jin, Tingting, et al.
(författare)
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Efficient heterogeneous integration of InP/Si and GaSb/Si templates with ultra-smooth surfaces
- 2022
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Ingår i: Science China Information Sciences. - : Springer Science and Business Media LLC. - 1869-1919 .- 1674-733X. ; 65:8
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Tidskriftsartikel (refereegranskat)abstract
- Heterogeneous integration of InP and GaSb on Si substrates holds a huge potential interest in near-infrared and mid-infrared optoelectronic devices. In this study, 2-inch 180-nm-thick InP and 185-nm-thick GaSb thin layers were successfully transferred onto the Si substrates to form high-quality and ultra-smooth InP/Si and GaSb/Si templates using molecular beam epitaxy (MBE) and the ion-slicing technique together with selective chemical etching. The relocation of the implantation-introduced damage in the sacrificial layer enables the transfer of relatively defect-free InP and GaSb thin films. The sacrificial layers were completely etched off by selective chemical etching, leaving ultra-smooth epitaxial surfaces with a roughness of 0.2 nm for the InP/Si template and 0.9 nm for the GaSb/Si template, respectively. Thus, the chemical mechanical polishing (CMP) process was not required to smooth the surface which usually introduces particles and chemical contaminations on the transferred templates. Furthermore, the donor substrate is not consumed and can be recycled to reduce the cost, which provides a paradigm for the sustainable and economic development of the Si integration platform.
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| 14. |
- Li, Junjie, et al.
(författare)
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A Novel Dry Selective Isotropic Atomic Layer Etching of SiGe for Manufacturing Vertical Nanowire Array with Diameter Less than 20 nm
- 2020
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Ingår i: Materials. - : MDPI AG. - 1996-1944. ; 13:3
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Tidskriftsartikel (refereegranskat)abstract
- Semiconductor nanowires have great application prospects in field effect transistors and sensors. In this study, the process and challenges of manufacturing vertical SiGe/Si nanowire array by using the conventional lithography and novel dry atomic layer etching technology. The final results demonstrate that vertical nanowires with a diameter less than 20 nm can be obtained. The diameter of nanowires is adjustable with an accuracy error less than 0.3 nm. This technology provides a new way for advanced 3D transistors and sensors.
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| 15. |
- Liang, Xiaoyan, et al.
(författare)
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Exosomal miR-532-5p induced by long-term exercise rescues blood–brain barrier function in 5XFAD mice via downregulation of EPHA4
- 2023
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Ingår i: Aging Cell. - : Wiley. - 1474-9718 .- 1474-9726. ; 22:1
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Tidskriftsartikel (refereegranskat)abstract
- The breakdown of the blood–brain barrier, which develops early in Alzheimer's disease (AD), contributes to cognitive impairment. Exercise not only reduces the risk factors for AD but also confers direct protection against cognitive decline. However, the exact molecular mechanisms remain elusive, particularly whether exercise can liberate the function of the blood–brain barrier. Here, we demonstrate that long-term exercise promotes the clearance of brain amyloid-β by improving the function of the blood–brain barrier in 5XFAD mice. Significantly, treating primary brain pericytes or endothelial cells with exosomes isolated from the brain of exercised 5XFAD mice improves cell proliferation and upregulates PDGFRβ, ZO-1, and claudin-5. Moreover, exosomes isolated from exercised mice exhibit significant changes in miR-532-5p. Administration or transfection of miR-532-5p to sedentary mice or primary brain pericytes and endothelial cells reproduces the improvement of blood–brain barrier function. Exosomal miR-532-5p targets EPHA4, and accordingly, expression of EphA4 is decreased in exercised mice and miR-532-5p overexpressed mice. A specific siRNA targeting EPHA4 recapitulates the effects on blood–brain barrier-associated cells observed in exercised 5XFAD mice. Overall, our findings suggest that exosomes released by the brain contain a specific miRNA that is altered by exercise and has an impact on blood–brain barrier function in AD.
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| 16. |
- Moretti, Rocco, et al.
(författare)
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Community-wide evaluation of methods for predicting the effect of mutations on protein-protein interactions
- 2013
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Ingår i: Proteins. - : Wiley. - 0887-3585 .- 1097-0134. ; 81:11, s. 1980-1987
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Tidskriftsartikel (refereegranskat)abstract
- Community-wide blind prediction experiments such as CAPRI and CASP provide an objective measure of the current state of predictive methodology. Here we describe a community-wide assessment of methods to predict the effects of mutations on protein-protein interactions. Twenty-two groups predicted the effects of comprehensive saturation mutagenesis for two designed influenza hemagglutinin binders and the results were compared with experimental yeast display enrichment data obtained using deep sequencing. The most successful methods explicitly considered the effects of mutation on monomer stability in addition to binding affinity, carried out explicit side-chain sampling and backbone relaxation, evaluated packing, electrostatic, and solvation effects, and correctly identified around a third of the beneficial mutations. Much room for improvement remains for even the best techniques, and large-scale fitness landscapes should continue to provide an excellent test bed for continued evaluation of both existing and new prediction methodologies. Proteins 2013; 81:1980-1987.
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| 17. |
- Song, Meiqi, et al.
(författare)
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Effects of Tool Tooth Number and Cutting Parameters on Milling Performance for Bamboo–Plastic Composite
- 2023
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Ingår i: Forests. - : MDPI. - 1999-4907. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Cutting force and temperature are critical indicators for improving cutting performance and productivity. This study used an up-milling experiment to ascertain the effect of tool tooth number, cutting speed, and depth on the machinability of bamboo–plastic composite. We focused on the changes in the resultant force and cutting temperature under different milling conditions. A response surface methodology was used to build prediction models for the resultant force and temperature. A verification test was conducted to prove the model’s reliability. The empirical findings suggested that the number of tool teeth had the most significant impacts on both the resultant force and the cutting temperature, followed by the depth of cut and the cutting speed. Moreover, the resultant force and cutting temperature showed increasing trends with decreasing numbers of tool teeth and increasing cut depths. However, cutting speed had a negative relationship with the resultant force and a positive relationship with temperature. We also determined the optimal milling conditions with the lowest force and temperature: four tool teeth, 300 m/min cutting speed, and 0.5 mm depth. This parameter combination can be used in the industrial manufacture of bamboo–plastic composite to improve tool life and manufacturing productivity.
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| 18. |
- Wang, Jinxin, et al.
(författare)
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Machining Properties of Stone-Plastic Composite Based on an Empirically Validated Finite Element Method
- 2023
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Ingår i: Advanced Engineering Materials. - : John Wiley & Sons. - 1438-1656 .- 1527-2648. ; 25:8
-
Tidskriftsartikel (refereegranskat)abstract
- High-cutting performance is an essential metric for improving the suitability of materials for industrial applications. Herein, the machining properties of stone-plastic composite are assessed through a finite element method to explore orthogonal cutting behavior by diamond cutters. The key aspects examined in this work are the effects of tool geometry and cutting parameters on the cutting force, temperature, chip formation, von Mises stress, and surface quality finish. Primary findings show that chip continuity increases proportionally with increase in rake angle but decreases with cutting speed and depth. Meanwhile, both cutting stability and surface quality are negatively correlated with cutting speed and depth but positively correlated with rake angle. These results support the adoption of cutting conditions using greater rake angle, higher cutting speed, and shallower cutting depth to obtain higher cutting performance, that is, greater cutting stability and surface quality in the finishing machining of stone-plastic composites.
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| 19. |
- Wang, Kui, et al.
(författare)
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Efficient electro-demulsification of O/W emulsions and simultaneous oil removal enabled by a multiscale porous biocarbon electrode
- 2024
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Ingår i: Chemical Engineering Journal. - : Elsevier BV. - 1385-8947 .- 1873-3212. ; 481
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Tidskriftsartikel (refereegranskat)abstract
- Emulsion wastewater contain substantial amounts of oil and various additives, which pose threats to the environment and human health. Demulsification is a crucial pretreatment stage for wastewater. This study aims to identify a novel electro-demulsification method with high oil removal efficiency and low energy consumption. Modified carbonized birch wood with a unique isotropic multiscale pore structure is used as a self-standing electrode to treat a toluene oil-in-water (O/W) emulsion. The electrode must have a highly porous structure to facilitate efficient water diffusion and oil adsorption. It must also have high electronic conductivity to expedite polarized molecular electrophoresis to realize penetration into the pores and, subsequently, demulsification. Guided by an applied electric field force, polarized O/W droplets are drawn toward the electrode, revealing electrical characteristics distinct from those of polarized organic molecules. This electric field force augments the capture and adhesion of droplets by the electric double layer at the electrode interface. Consequently, adsorbed droplets in close proximity to the electrode rupture due to the combined influence of the electric field force and the electrostatic effects stemming from the electrode's multiscale porous structure. This synergistic action enables demulsification to occur efficiently at low energy consumption levels. This study has revealed that electro-demulsification can effectively treat toluene emulsions stabilized by various surfactants and microemulsion containing toluene. Therefore, this electro-demulsification technology can be further developed for various types of water pollution.
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| 20. |
- Wei, Hong, et al.
(författare)
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Analysis of Cutting Performance in High Density Fiberboard Milling by Ceramic Cutting Tools
- 2018
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Ingår i: Wood research. - : Slovak Forest Products Research. - 1336-4561. ; 63:3, s. 455-466
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Tidskriftsartikel (refereegranskat)abstract
- In order to study the cutting performance of TiC reinforced Al2O3 ceramic cutting tools in milling high density fiberboard, the effects of cutting parameter on the cutting forces, tool wear and cutting quality were investigated. Under the condition of same average chip thickness, feed per tooth and geometry angles, firstly, the change rate of maximum cutting forces were higher than that of average cutting forces at two different cutting speeds, and the cutting forces at high speed cutting was less than that at low speed cutting. Secondly, the flank wear at high speed cutting was more pronounced than that at low speed cutting, whose abnormal wear were pull-out of grain, cracking, chipping and flanking. Thirdly, the machining quality at high speed cutting was better than that at low speed cutting. Fourthly, the tendencies of cutting forces, tool wear and surface roughness relative to cutting length were similar, but the change rates were different, especially at the initial stage. Finally, high speed cuttingare plausible to use in HDF processing, which not only improves machining quality, but also promotes production efficiency.
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| 21. |
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| 22. |
- Wu, Zhanwen, et al.
(författare)
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Investigation on Milling Quality of Stone–Plastic Composite Using Response Surface Methodology
- 2022
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Ingår i: JOM. - : Springer. - 1047-4838 .- 1543-1851. ; 74:5, s. 2063-2070
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Tidskriftsartikel (refereegranskat)abstract
- To improve the cutting quality of stone–plastic composites, a series of milling experiments were performed using the response surface, binary, and microanalysis methodologies, paying special attention to the effects of milling parameters (rake angle from 6° to 14°, spindle speed from 5000 rpm to 7000 rpm, feed rate from 10 m/min to 20 m/min, and milling depth from 0.5 mm to 2 mm) on the quality of the machined surface. Surface damage was mainly concentrated on the crest and two axial sides of the milling wave, with cracking and pitting identified as the main damage patterns. These experiments determined that the optimal conditions for milling stone–plastic composite with minimal surface roughness are a rake angle of 10°, cutting speed of 37.9 m/s, feed per tooth of 0.32 mm, and milling depth of 0.5 mm. The mathematical model for surface roughness developed from these results is highly reliable and could be used for the prediction and optimization of surface roughness during industrial manufacturing of stone–plastic composites.
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| 23. |
- Yan, Bing, et al.
(författare)
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Bismuth-induced band-tail states in GaAsBi probed by photoluminescence
- 2019
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 114:5
-
Tidskriftsartikel (refereegranskat)abstract
- Band-tail states in semiconductors reflect the effects of material growth and/or treatment, affect the performance of optoelectronic applications, and are hence a well-concerned issue. Dilute-Bi GaAs is considered very competitive though the role of Bi is yet to be well clarified. We in this letter investigate the effect of Bi incorporation on the band-tail states in GaAs 1−x Bi x by excitation power- and magnetic field-dependent photoluminescence (PL) measurements at low temperatures. Three PL features are identified from a broad PL peak, which blue-shift monotonically with the increase in excitation power. None of the PL features correlate with single Bi-content free-exciton recombination, and band-tail filling rather than the donor-acceptor pair process is responsible for the power-induced blueshift. The density of band-tail states gets enhanced with the increase in the Bi incorporation level and affects the determination of Bi-induced bandgap reduction. The results indicate that joint analysis of excitation- and magneto-PL may serve as a good probe for band-tail states in semiconductors.
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| 24. |
- Yu, Yingyue, et al.
(författare)
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Neuro-fuzzy assessment of machined wood fibre–reinforced magnesium oxide composite
- 2023
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Ingår i: Wood Material Science & Engineering. - : Taylor & Francis. - 1748-0272 .- 1748-0280. ; 18:3, s. 1151-1159
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Tidskriftsartikel (refereegranskat)abstract
- High quality processing key to improving product quality and enterprise benefits. In this work, an adaptive network–based fuzzy inference system (ANFIS) was combined with milling experiments to understand the effects of tool geometry and milling parameters on the surface quality of wood fibre–reinforced magnesium oxide composite (WRMC). Specifically, changes in surface roughness (Ra) and damage of WRMC at different milling conditions were assessed using ANFIS and micro-analysis methods. Development of ANFIS models were confirmed to be reliable for predicting surface roughness. Changes in surface roughness at different milling conditions were determined, and the lowest surface roughness was obtained at the highest rake angle, highest cutting speed, and smallest milling depth. Furthermore, pitting-type damage irregularly distributed on the machined surface is attributed to the pulling out and debonding of wood fibres. Overall, high cutting speed, shallow cutting depth, and high rake angle is recommended for fine machining of WRMC where a smooth surface is desired. This study showcases how neuro-fuzzy models can be combined with conventional micro-analysis to optimize milling parameters for WRMC to minimize surface damage, and paves the way for future studies to optimize cutting tool life and energy consumption.
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| 25. |
- Zhu, Zhaolong, et al.
(författare)
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Assessment of Cutting Forces and Temperature in Tapered Milling of Stone–Plastic Composite Using Response Surface Methodology
- 2020
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Ingår i: JOM. - : Springer. - 1047-4838 .- 1543-1851. ; 72:11, s. 3917-3925
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Tidskriftsartikel (refereegranskat)abstract
- In the machining of stone–plastic composites, the cutting efficiency and increased economy are important considerations. To this end, stone–plastic composite was up-milled using tapered cutters. Cutting forces and temperature were measured under varied angle geometries and cutting parameters. Response surface methodology allowed the analysis of changes in cutting forces and temperature, and the significant contributions of each variable and their two-level interactions were determined. Correlations between actual and predicted results were found by developing mathematical models for cutting forces and temperature, which can be used to make accurate predictions. Finally, the optimisation of cutting conditions for tapered milling stone–plastic composites by minimising cutting forces and temperature was determined as taper angle 75°, feed per tooth 0.44 mm and cutting depth 0.5 mm. It is proposed that these parameters be adopted in industrial machining for higher machining efficiency and lower production cost.
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| 26. |
- Zhu, Zhaolong, et al.
(författare)
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Cutting performance in the helical milling of stone-plastic composite with diamond tools
- 2020
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Ingår i: CIRP - Journal of Manufacturing Science and Technology. - : Elsevier. - 1755-5817 .- 1878-0016. ; 31, s. 119-129
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Tidskriftsartikel (refereegranskat)abstract
- With the aim of providing scientific guidance for the application of diamond cutting tools to the machining of stone-plastic composite, this work presents results on the influence of tool geometry and cutting parameters on cutting forces and temperature during helical milling of stone–plastic composite with diamond cutters. Four factors—helical angle, spindle speed, feed rate, and cutting depth—were assessed using a response surface method. Mathematical models were developed and identified by verification testing to accurately predict changes in cutting forces and temperature during composite helical milling. Then, the significant contributions of each factor and of two-factor interactions were determined by analysis of variance, and the trends of cutting forces and temperature were studied using response surface methodology. The optimal conditions in terms of low cutting forces and temperature were determined to be a helical angle of 70°, cutting speed of 51.3 m/s, feed per tooth of 0.24 mm, and cutting depth of 0.5 mm. These parameters are proposed for use in the industrial production of stone–plastic composite material to improve machining efficiency.
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| 27. |
- Zhu, Zhaolong, et al.
(författare)
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Effect of Cutting Speed on Machinability of Stone–Plastic Composite Material
- 2019
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Ingår i: Science of Advanced Materials. - : American Scientific Publishers. - 1947-2935 .- 1947-2943. ; 11:6, s. 884-892
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Tidskriftsartikel (refereegranskat)abstract
- This research examined the orthogonal cutting of stone–plastic composite with diamond cutting tools. The objective was to quantify features relating to machinability, including cutting forces, cutting heat, chip formation, and machining quality with respect to cutting speed. The conclusions are as follows. An increased cutting speed promotes a decrease in the resulting force, causes cutting temperature to increase, makes the cutting processes more stable, and reduces the surface roughness. Chip-breaking length increases with an increase in cutting speed, and chip morphology changes from particle, to curve, to helical, and finally, to flow chips. Overall, a higher cutting speed is more suitable for machining stone–plastic composite materials: it not only increases the stability of cutting process, but also improves the final product of stone–plastic composite by promoting production of a smoother surface.
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| 28. |
- Zhu, Zhaolong, et al.
(författare)
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Energy Efficiency Optimization for Machining of Wood Plastic Composite
- 2022
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Ingår i: Machines. - : MDPI. - 2075-1702. ; 10:2
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Tidskriftsartikel (refereegranskat)abstract
- Enhancing energy efficiency is the key to realizing green manufacturing. One major area of interest in this regard is the improvement of energy efficiency of machine tools during the production of building materials. This project focuses on energy efficiency during the spiral milling of wood plastic composites. To this end, a response surface method was adopted to develop a model and establish the relationship between energy efficiency and milling conditions. Analysis of variance based on individual factors as well as two-factor interactions was performed to gauge their effects on energy efficiency. It was found that milling depth was positively correlated to power efficiency, while spiral angle and feed per tooth displayed non-monotonic behavior. An attempt was made to predict milling conditions that will yield the greatest material removal rate and power efficiency. For wood plastic composites subjected to up-milling, it was determined that a feed per tooth of 0.1 mm, milling depth of 1.5 mm, and spiral angle of 70° were ideal. Considering the potential improvements in energy efficiency and surface quality that these process parameters will bring, it is strongly recommended for use in the industrial machining of wood plastic composites.
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| 29. |
- Zhu, Zhaolong, et al.
(författare)
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Frictional behaviour of wood-Plastic composites against cemented carbide during sliding contact
- 2023
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Ingår i: Wood Material Science & Engineering. - : Taylor & Francis. - 1748-0272 .- 1748-0280. ; 18:3, s. 1127-1133
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Tidskriftsartikel (refereegranskat)abstract
- This study provides guidelines for the industrial machining of wood-plastic composites, focusing on their behaviour under friction, specifically when friction is caused by sliding contact with cemented carbide. Using the response surface method (RSM) to explore the correlation between the friction coefficient and the wood-plastic composite type, loading force, and reciprocating frequency, a series of frictional tests were performed. The significant contributions of each factor and their two-factor interactions were determined by analysis of variance (ANOVA), with a significance level of 5%, while trends in the variation of the friction coefficient were investigated by using a response surface methodology. The wood-plastic composite types had the greatest impact on the friction coefficient, followed by loading force and reciprocating frequency. A mathematical model (CoF = −0.10 + 0.09ω−0.02f+0.01Fn−0.01ωf+2.38×10−3ωFn−2.00×10−4Fnf+0.11ω2+2.96f2−1.04×10−4Fn2) was developed to accurately predict changes in the friction coefficient during machining of such composites. According to the results of the optimisation, wood-plastic composite with polypropylene should be machined with high-speed cutting, whereas those with polyethylene and polyvinyl chloride are recommended for low-speed machining, so as to ensure the lowest friction coefficient.
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| 30. |
- Zhu, Zhaolong, et al.
(författare)
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High-quality and high-efficiency machining of stone-plastic composite with diamond helical cutters
- 2020
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Ingår i: Journal of Manufacturing Processes. - : Elsevier. - 1526-6125. ; 58, s. 914-922
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Tidskriftsartikel (refereegranskat)abstract
- Stone-plastic composite is a relatively new engineering material that is widely used in the decoration industry. Determination of the optimal machining conditions for this composite is important for the manufacturing industry. This work investigates the cutting quality of stone-plastic composite during helical milling with diamond cutters, focusing on the damage mechanism and surface roughness of the machined surface. Response surface methodology was used to model and establish the relationship between surface roughness and cutting conditions. Analysis of variance was adopted to study the significant contributions of each factor and two-factor interactions on surface roughness. An inclined U-shaped waviness was found on the machined surface, with damage patterns of cracking and pitting mainly located in the peaks of the cutting waves. The optimal combination for cutting was found to be a helical angle of 70°, cutting speed of 51.2 m/s, feed per tooth of 0.26 mm, and cutting depth of 0.72 mm; hence, these parameters are proposed for use in industrial stone-plastic composite machining for optimal cutting quality and machining efficiency.
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| 31. |
- Zhu, Zhaolong, et al.
(författare)
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Machinability investigation in turning of high density fiberboard
- 2018
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Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 13:9, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- A series of experiments were conducted to assess the machinability of high density fiberboardusing cemented carbide cutting tools. The objective of this work was to investigate theinfluence of two cutting parameters, spindle speed and feed per turn, on cutting forces, chipformation and cutting quality. The results are as follows: cutting forces and chip-breakinglength decrease with increasing spindle speed and decreasing feed per turn. In contrast,surface roughness increases with decrease of spindle speed and increase in feed perturn. Chips were divided into four categories based on their shape: dust, particle, splinter,and semicontinuous chips. Chip-breaking length had a similar tendency to the varianceof cutting forces with respect to average roughness and mean peak-to-valley height: anincrease in the variance of cutting forces resulted in increased average roughness andmean peak-to-valley height. Thus, high cutting speed and low feed rate are parameters suitablefor high-quality HDF processing and will improve not only machining quality, but productionefficiency.
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| 32. |
- Zhu, Zhalong, et al.
(författare)
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Machinability of Different Wood-Plastic Composites during Peripheral Milling
- 2022
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Ingår i: Materials. - : MDPI. - 1996-1944. ; 15:4
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to improve the machinability of wood-plastic composites by exploring the effects of different wood-plastic composites on machinability. In particular, the effects of milling with cemented carbide cutters were assessed by investigating cutting forces, cutting temperature, surface quality, chip formation, and tool wear. The cutting parameters determined to yield an optimal surface quality were rake angle 2°, cutting speed 9.0 m/s, feed per tooth 0.3 mm, and cutting depth 1.5 mm. In these optimized milling conditions, the wood-plastic composite with polypropylene exhibited the highest cutting forces, cutting temperature, and tool wear, followed by polyethylene and polyvinyl chloride wood-plastic composites. Two wear patterns were determined during wood-plastic composite machining, namely chipping and flaking. Due to the different material composition, semi-discontinuous ribbon chips and continuous ribbon chips were generated from the machining process of wood-plastic composites with polypropylene and polyethylene, respectively. The wood-plastic composite with polyvinyl chloride, on the other hand, formed needle-like chips. These results contribute to a theoretical and practical basis for improved wood-plastic composite machining in industrial settings.
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| 33. |
- Zhu, Zhaolong, et al.
(författare)
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Machinability of stone-plastic materials during diamond planing
- 2019
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Ingår i: Applied Sciences. - Basel, Switzerland : MDPI. - 2076-3417. ; 9:7
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Tidskriftsartikel (refereegranskat)abstract
- This paper investigated the machinability of a stone–plastic composite (SPC) via orthogonal cutting with diamond cutters. The objective was to determine the effect of cutting depth on its machinability, including cutting forces, heat, chip formation, and cutting quality. Increased cutting depth promoted an increase in both frictional and normal forces, and also had a strong influence on the change in normal force. The cutting temperatures of chips and tool edges showed an increasing trend as cutting depth increased. However, the cutting heat was primarily absorbed by chips, with the balance accumulating in the cutting edge. During chip formation, the highest von Mises strain was mainly found in SPC ahead of the cutting edge, and the SPC to be removed partially passed its elastic limit, eventually forming chips with different shapes. Furthermore, the average surface roughness and the mean peak-to-valley height of machined surfaces all positively correlated to an increase in cutting depth. Finally, with an increase in cutting depth, the chip shape changed from tubular, to ribbon, to arc, to segmental, and finally, to helical chips. This evolution in chip shape reduced the fluctuation in cutting force, improving cutting stability and cutting quality.
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| 34. |
- Zhu, Zhaolong, et al.
(författare)
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Performance of stone-plastic composites with different mix ratios during orthogonal cutting
- 2019
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Ingår i: Materials Express. - : American Scientific Publishers. - 2158-5849 .- 2158-5857. ; 9:7, s. 749-756
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Tidskriftsartikel (refereegranskat)abstract
- The present study aimed to increase understanding of the machinability of stone-plastic materials with different mix ratios subjected to diamond planing. To that end, orthogonal cutting was carried out. Different stone-plastic materials were machined by diamond cutting tools to produce chips. Based on the results, four conclusions are drawn: (1) Among stone-plastic materials with decreasing polyvinyl chloride content ratio, the maximum cutting forces and fluctuation of dynamic forces show decreasing trends, and cutting stability increases. (2) The temperature of chips is slightly higher than that of tool edges; the cutting heat generated during machining is mainly absorbed by the chips of removed material and, to a lesser extent, stored in the tool edge. The type of stone-plastic material has a great effect on the changes in the temperatures of chip and tool edge. (3) With a decrease in polyvinyl chloride content, the chip shapes evolve from crack, to arc, and eventually to elemental chips. (4) The cutting quality of the machined surface improves with a decrease in the polyvinyl chloride content ratio of the stone-plastic materials.
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| 35. |
- Zhu, Zhaolong, et al.
(författare)
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Research on cutting performance of ceramic cutting tools in milling high density fiberboard
- 2017
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Ingår i: Wood research. - : Statny Drevarsky Vyskumny Ustav. - 1336-4561. ; 62:1, s. 125-138
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Tidskriftsartikel (refereegranskat)abstract
- The effect of cutting parameters and tool parameters on cutting forces and tool wear wereinvestigated in high density fiberboard (HDF) peripheral up-milling using toughened ceramiccutting tools. The results showed that whether at low speed cutting or high speed cutting, thetangential forces Ft and normal forces Fr increased slowly with the increase of cutting length. Thetangential forces Ft and normal forces Fr at low speed cutting were higher than that at high speedcutting. The tangential forces Ft and normal forces Fr decreased with the decrease of wedge anglein the same rake angle. Then, the effect of high cutting speed on the flank wear was greater thanthat at low cutting speed. The bigger wedge angle tools led to the serious flank wear. The mainwear pattern in milling HDF consisted of pull-out of the grain, flaking, chipping and cracking,the main wear mechanism were adhesive and abrasive wear
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