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Switching Frequency Improvement of a High Speed on/off Valve Based on Pre-excitation Control Algorithm

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Chinese Journal of Mechanical Engineering 2024年第4期 107-119页

作者： Qi zh.ng Xiaotian Li Yongxin Mao Enguang xu Tiwei Jia Yanbiao Li Huayong Yang College of Mechanical Engineering Zhejiang University of Technology State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University Key Laboratory of Special Purpose Equipment and Advanced Processing Technology Ministry of Education and Zhejiang ProvinceZhejiang University of Technology

The high-speed on/off valve(HSV) serves as the fundamental component responsible for generating discrete fluids within digital hydraulic systems. As the switching frequency of the HSV increases, the properties of the generated discrete fluid approach those of continuous fluids. Therefore, a higher frequency response characteristic of HSV is the key to ensure the control accuracy of digital hydraulic systems. However, the current research mainly focuses on its dynamic performance, but neglect its FRC. This paper presents a theoretical analysis demonstrating that the FRC of the HSV can be enhanced by minimizing its switching time. The maximum switching frequency(MSF) is mainly determined by opening dynamic performance when HSV operates with low switching duty ratio(SDR), whereas the closing dynamic performance limits the MSF when HSV operates with high SDR. Building upon these findings,the pre-excitation control algorithm(PECA) is proposed to reduce the switching time of the HSV, and consequently enhance its FRC. Experimental results demonstrate that PECA shortens the opening delay time of HSV by 1.12 ms,the closing delay time by 2.54 ms, and the closing moving time by 0.47 ms in comparison to the existing advanced control algorithms. As a result, a larger MSF of 417 Hz and a wider controllable SDR range from 20% to 70% were achieved at a switching frequency of 250 Hz. Thus, the proposed PFCA in this paper has been verified as an effective and promising approach for enhancing the control performance of digital hydraulic systems.

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Electrocatalytic CO_(2) reduction to C_(2)H_(4): From lab to fab

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Journal of Energy Chemistry 2024年第3期90卷 540-564,I0012页

作者： Zeyu Guo Fabao Yang Xiaotong Li Huiwen zhu Hainam Do Kam Loon Fow Jonathan D.Hirst Tao Wu Qiulin Ye Yaqi Peng Hao Bin Wu Angjian Wu Mengxia xu Department of Chemical and Environmental Engineering and New Materials InstituteUniversity of Nottingham Ningbo ChinaNingbo 315100ZhejiangChina Key Laboratory of Carbonaceous Waste Processing and Process Intensification of zhejiang Province University of Nottingham Ningbo ChinaNingbo 315100ZhejiangChina Nottingham Ningbo China Beacons of Excellence Research and Innovation Institute University of Nottingham Ningbo ChinaNingbo 315100ZhejiangChina State Key Laboratory of Clean Energy Utilization Department of Energy EngineeringZhejiang UniversityHangzhou 310027ZhejiangChina Institute for Composites Science Innovation(InCSI)and State Key Laboratory of Silicon and Advanced Semiconductor Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027ZhejiangChina School of Chemistry University of NottinghamUniversity ParkNottingham NG72RDUK Baima Lake Laboratory Hangzhou 310053ZhejiangChina

The global concerns of energy crisis and climate change,primarily caused by carbon dioxide(CO_(2)),are of utmost ***,the electrocatalytic CO_(2) reduction reaction(CO_(2)RR) to high value-added multi-carbon(C_(2+)) products driven by renewable electricity has emerged as a highly promising solution to alleviate energy shortages and achieve carbon *** these C_(2+) products,ethylene(C_(2)H_(4))holds particular importance in the petrochemical ***,this review aims to establish a connection between the fundamentals of electrocatalytic CO_(2) reduction reaction to ethylene(CO_(2)RRto-C_(2)H_(4)) in laboratory-scale research(lab) and its potential applications in industrial-level fabrication(fab).The review begins by summarizing the fundamental aspects,including the design strategies of high-performance Cu-based electrocatalysts and advanced electrolyzer ***,innovative and value-added techniques are presented to address the inherent challenges encountered during the implementations of CO_(2)RR-to-C_(2)H_(4) in industrial ***,case studies of the technoeconomic analysis of the CO_(2)RR-to-C_(2)H_(4) process are discussed,taking into factors such as costeffectiveness,scalability,and market *** review concludes by outlining the perspectives and challenges associated with scaling up the CO_(2)RR-to-C_(2)H_(4) *** insights presented in this review are expected to make a valuable contribution in advancing the CO_(2)RR-to-C_(2)H_(4) process from lab to fab.

关键词： CO_(2) electroreduction reaction Ethylene Gas diffusion electrode Machine learning Density functional theory Techno-economic analysis

Involvement of apoptosis of alveolar epithelial cells in acute pancreatitis-associated lung injury

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World Journal of Gastroenterology 2000年第6期6卷 920-924页

作者： Yuan YZ Gong zh Lou KX Tu SP zhai ZK xu JY Shanghai Med Univ 2 Ruijin Hosp Dept Gastroenterol Shanghai 200025 Peoples R China

INTRODUCTIONAcute pancreatitis in a common and potentially fataldisease which is associated with considerablemorbidity and a mortality rate of approximately30%;its pathogenesis remains *** of death is often due to mul... 详细信息

关键词： pancreatitis lung/injuries apoptosis protein P53 immunohistochemistry platelet activating factor

Experimental and numerical investigation of Weibullian behavior of grain crushing strength

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Geoscience Frontiers 2020年第2期11卷 401-411页

作者： Quanshui Huang Wei zhou Gang Ma Tang-Tat ng Kun xu State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering Wuhan UniversityMinistry of EducationWuhan 430072China University of New Mexico AlbuquerqueNM87131USA

The Weibullian behavior of single grain crushing strength was investigated experimentally and numerically with the aim of enhancing the understanding of rock grain *** morphologies of pebble grains were obtained using white light 3D laser scanning and image processing.A grain shape library was constructed for grain shape analysis with different shape *** use of the shape library and grain stability analysis is discussed for a suggested procedure to rotate a grain to its most stable *** grain crushing tests were performed for 30 pebbles to obtain force-displacement curves and fracture *** grain was compressed diametrically between flat *** expected,the values of the stress at bulk fracture follow a Weibull distribution.A procedure for generating crushable agglomerates with realistic particle shapes was demonstrated,which was accomplished in the discrete element modeling(DEM)of the single grain crushing *** work presented here is novel in that both the heterogeneous micro-structures and randomly distributed flaws are *** DEM results demonstrate that the proposed modeling approach and calibrated parameters are reliable and can reflect the crushing behavior of rock ***,three parametric studies were presented evaluating the effects of micro-crack density,micro-crack disorder,and grain morphology on the Weibullian behavior of the crushing strength,none of which has previously been thoroughly *** three studies provide a deeper insight into the origin of the Weibullian behavior of single grain crushing strength.

关键词： Rock grain Grain crushing test Discrete element modeling 3D scanning technique Grain stability Weibullian behavior

基质辅助激光解吸电离-飞行时间质谱法快速测定米饭和乳制品中蜡样芽孢杆菌呕吐毒素Cereulide

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食品科学 2024年第1期45卷 232-238页

作者：曾羲王宇徐巨才黄穗东王涓徐振林华南农业大学食品学院广东省食品质量安全重点实验室广东广州510642 广州市食品检验所广东广州511400 五邑大学生物科技与大健康学院江门市大健康国际创新研究院广东江门529020

建立基质辅助激光解吸电离-飞行时间质谱(matrix-assisted laser desorption ionization time-of-flight mass spectrometry,MALDI-TOF MS)法分析蜡样芽孢杆菌呕吐毒素Cereulide的快速检测方法。分析了Cereulide标准物质的裂解规律,考察基质种类、点靶方式、基质溶剂和用量、激光强度等对Cereulide的质谱信号强度的影响,并进行方法学验证和实际样品检测。结果表明,选择以α-氰基-4-羟基肉桂酸为基质,均匀分散在50%乙腈-水(含0.1%三氟乙酸)中,采用先点基质再点样品的点样方式,反射线性正离子模式下选择激光强度70%进行食品中MALDI-TOF MS筛查时,可检测到Cereulide的[M+Na]^(+)和[M+K]^(+)目标离子峰,此质谱信号稳定、强度高、响应重复性好。方法学验证结果表明,Cereulide的[M+Na]^(+)和[M+K]^(+)目标离子峰在5~100 ng/mL范围内线性好,相关系数(r)>0.99;方法的检出限分别为3.0 ng/g和5.0 ng/g;对米饭和牛乳样品的加标回收率为73.3%~118.2%,相对标准偏差为0.3%~10.9%(n=6)。本方法分析速度快、准确性高、灵敏度好、抗干扰能力强、无需内标即可实现对米饭和乳制品中Cereulide的批量筛查和检测。

关键词：基质辅助激光解吸-电离飞行时间质谱蜡样芽孢杆菌呕吐毒素 α-氰基-4-羟基肉桂酸

Propagating characteristics of waves on a thin layer of mud

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Journal of Hydrodynamics 2021年第5期33卷 1078-1088页

作者： Hai-jue xu Jin-sen Wu Yu-chuan Bai Dong-qiang Lu Chiu-On ng State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China Shanghai Institute of Applied Mathematics and Mechanics School of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China Department of Mechanical Engineering The University of Hong KongHong KongChina

The propagating characteristics of the water and muddy waves are one of the concerns of theoretical studies because of the following facts:(1)With the development of the economy in the estuaries,local residents and government paid increasing attention to the ecological environment of the estuarine beaches The propagating characteristics of the water and muddy waves are closely related to the ecological environment,the concern of the government and the residents.(2)The propagating characteristics of the mud are the bottleneck of the study of the coastal and beach dynamics because of the complicated constitutive relation of the *** different constitutive models may lead to different explanations of its ***,the proper selection of the model is one of the keys to reveal the true kinematic properties of the mud in the *** paper first establishes a power law model of the constitutive relation of the *** on this model,a gravity wave theory is *** to the mechanism of the mud wave transportation,the coupled mud-water wave field can be divided into two *** upper layer is described as the viscous Newtonian fluid,whereas the lower high-concentration mud layer is described as the power law ***,the equations of the proposed model are discretized and the calculations are made by using the difference ***,the propagating characteristics are discussed,and the dispersion relations of the water and mud waves are analyzed in detail.

关键词： Estuary two-layer fluid model power law model gravity wave Introduction

An AlGaN/GaN HEMT with a reduced surface electric field and an improved breakdown voltage

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Chinese Physics B 2012年第8期21卷 360-364页

作者：谢刚 Edward xu Niloufar Hashemi 张波 Fred Y.Fu Wai Tung ng The Edward S.Rogers Sr.Electrical and Computer Engineering Department University of Toronto State key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Crosslight Software Inc.Burnaby BCCanada

A reduced surface electric field in an AlGaN/GaN high electron mobility transistor （HEMT） is investigated by employing a localized Mg-doped layer under the two-dimensional electron gas （2-DEG） channel as an electric field shaping layer. The electric field strength around the gate edge is effectively relieved and the surface electric field is distributed evenly as compared with those of HEMTs with conventional source-connected field plate and double field plate structures with the same device physical dimensions. Compared with the HEMTs with conventional sourceconnected field plates and double field plates, the HEMT with a Mg-doped layer also shows that the breakdown location shifts from the surface of the gate edge to the bulk Mg-doped layer edge. By optimizing both the length of Mg-doped layer, Lm, and the doping concentration, a 5.5 times and 3 times the reduction in the peak electric field near the drain side gate edge is observed as compared with those of the HEMTs with source-connected field plate structure and double field plate structure, respectively. In a device with VGS = -5 V, Lm 1.5 m, a peak Mg doping concentration of 8×10^17 cm-3 and a drift region length of 10 m, the breakdown voltage is observed to increase from 560 V in a conventional device without field plate structure to over 900 V without any area overhead penalty.

关键词： AlGaN/GaN HEMT reduced surface electric field Mg-doped layer breakdown voltage

Reproductive medicine gets a new tool

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分子细胞生物学报:英文版 2011年第6期3卷 320-321页

作者： Wei-Xia Ang Cheng-xu Delon Toh Huck-Hui ng Yuin-Han Loh Epigenetics and Cell Fates Laboratory A*STAR Institute of Medical BiologySingapore 138648Singapore NUS Graduate School for Integrative Sciences and Engineering Singapore 117597Singapore Department of Biological Sciences National University of SingaporeSingapore 117543Singapore Gene Regulation Laboratory Genome Institute of SingaporeSingapore 138672Singapore Department of Biochemistry National University of SingaporeSingapore 117597Singapore School of Biological Sciences Nanyang Technological UniversitySingapore 639798Singapore

Infertility is a problem faced by millions *** a recent paper published in Cell,Hayashi et al.(2011)provided a potential solution for male infertility through the generation of functional spermatozoa that can give ris... 详细信息

关键词： infertility offspring

Taurine attenuates activation of hepatic stellate cells by inhibiting autophagy and inducing ferroptosis

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World Journal of Gastroenterology 2024年第15期30卷 2143-2154页

作者： Sen Li Qian-Jun Ren Can-Hao Xie Yang Cui Li-Tao xu Yi-Dan Wang Su Li Xing-Qiu Liang Bin Wen Ming-Kun Liang Xiao-Fang zhao Department of Basic Science Guangxi University of Chinese MedicineNanning 541100Guangxi Zhuang Autonomous RegionChina Department of Science and Technology Ruikang Hospital Affiliated to Guangxi University of Chinese MedicineNanning 541100Guangxi Zhuang Autonomous RegionChina Traditional Chinese Medicine Specialty Office Ruikang Hospital Affiliated to Guangxi University of Chinese MedicineNanning 541100Guangxi Zhuang Autonomous RegionChina

BACKGROUND Liver fibrosis is a compensatory response during the tissue repair process in chronic liver injury,and finally leads to liver cirrhosis or even hepatocellular *** pathogenesis of hepatic fibrosis is associated with the progressive accumulation of activated hepatic stellate cells(HSCs),which can transdiffer-entiate into myofibroblasts to produce an excess of the extracellular matrix(ECM).Myofibroblasts are the main source of the excessive ECM responsible for hepatic ***,activated hepatic stellate cells(aHSCs),the principal ECM producing cells in the injured liver,are a promising therapeutic target for the treatment of hepatic *** To explore the effect of taurine on aHSC proliferation and the mechanisms *** Human HSCs(LX-2)were randomly divided into five groups:Normal control group,platelet-derived growth factor-BB(PDGF-BB)(20 ng/mL)treated group,mmol/L,respectively)with PDGF-BB(20 ng/mL)treated *** Counting Kit-8 method was performed to evaluate the effect of taurine on the viability of ***-linked immunosorbent assay was used to estimate the effect of taurine on the levels of reactive oxygen species(ROS),malondialdehyde,glutathione,and iron *** electron microscopy was applied to observe the effect of taurine on the autophagosomes and ferroptosis features in *** real-time polymerase chain reaction and Western blot analysis were performed to detect the effect of taurine on the expression ofα-SMA,Collagen I,Fibronectin 1,LC3B,ATG5,Beclin 1,PTGS2,SLC7A11,and *** Taurine promoted the death of aHSCs and reduced the deposition of the *** with taurine could alleviate autophagy in HSCs to inhibit their activation,by decreasing autophagosome formation,downregulating LC3B and Beclin 1 protein expression,and upregulating p62 protein ***,treatment with taurine triggered ferroptosis and ferritinophagy to eliminate aHSCs characterized b

关键词： Hepatic stellate cells Autophagy Ferroptosis Molecular docking Taurine