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Selective electrochemical etching of cantilever-type SOI-MEMS devices

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Nanotechnology and Precision Engineering 2022年第2期5卷 21-26页

作者： Xiuchun Hao Peiling he xin li School of Mechanical Engineering Jiangsu University301 Xuefu RoadZhenjiang CityJiangsu ProvinceChina

It is possible to achieve selective electrochemical etching between different materials,such as p-and n-type silicon.However,achieving selective electrochemical etching on two different regions of the same p-type silicon material is a problem that has rarely been considered.herein,a novel selective electrochemical etching technique for cantilever-type silicon-on-insulator(SOI)wafer-based microswitches is proposed.In this study,a p-type handle layer was selectively etched,and a p-type device layer was passivated.This was achieved using a circuit with two voltage sources:voltages of−1.2 and 0 V were applied to the handle and device layers,respectively.It was found that the proposed etching process can effectively prevent the in-use sticking of a cantilever-type switch.This is accomplished by increasing the gap between the device layer and its underlying handle layer and increasing the roughness of these layers.The technique is applicable to the fabrication of various cantilever-type SOI microelectromechanical systems,irrespective of the resistivity of the SOI wafer.

关键词： SOI-MEMS selective electrochemical etching cantilever-type switch sticking

A benzenesulfonic acid-modified organic polymer monolithic column with reversed-phase/hydrophilic bifunctional selectivity for capillary electrochromatography

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Journal of Pharmaceutical Analysis 2023年第2期13卷 209-215页

作者： Yikun liu Ning he Yingfang Lu Weiqiang li xin he Zhentao li Zilin Chen Department of Orthopedics Trauma and Microsurgery Zhongnan Hospital of Wuhan UniversitySchool of Pharmaceutical SciencesWuhan UniversityWuhan430072China Key Laboratory of Combinatorial Biosynthesis and Drug Discovery Ministry of EducationHubei Province Engineering and Technology Research Center for Fluorinated PharmaceuticalsWuhan430071China

here,a styrene-based polymer monolithic column poly(VBS-co-TAT-co-AHM)with reversed-phase/hydrophilic interaction liquid chromatography(RPLC/HIliC)bifunctional separation mode was success-fully prepared for capillary electrochromatography by the in situ polymerization of sodium p-styrene sulfonate(VBS)with cross-linkers 3-(acryloyloxy)-2-hydroxypropyl methacrylate(AHM)and 1,3,5-triacryloylhexahydro-1,3,5-triazine(TAT).The preparation conditions of the monolith were optimized.The morphology and formation of the poly(VBS-co-TAT-co-AHM)monolith were confirmed by scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FT-IR).The separation perfor-mances of the monolith were evaluated systematically.It should be noted that the incorporation of VBS functional monomer can provideπ-πinteractions,hydrophilic interactions,and ion-exchange in-teractions.hence,the prepared poly(VBS-co-TAT-co-AHM)monolith can achieve efficient separation of thiourea compounds,benzene series,phenol compounds,aniline compounds and sulfonamides in RPLC or HIliC separation mode.The largest theoretical plate number for N,N0-dimethylthiourea reached 1.7×10^(5)plates/m.In addition,the poly(VBS-co-TAT-co-AHM)monolithic column showed excellent reproducibility and stability.This novel monolithic column has great application value and potential in capillary electrochromatography(CEC).

关键词： Sodium p-styrene sulfona Stationary phase Monolithic column Capillary electrochromatography Bifunctional interaction

Efficient normalization for quantitative evaluation of the driving behavior using a gated auto-encoder

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Frontiers of Information Technology & Electronic Engineering 2022年第3期23卷 452-462页

作者： xin he Zhe ZHANG li XU Jiapei YU College of Electrical Engineering Zhejiang UniversityHangzhou 310027China

Driving behavior normalization is important for a fair evaluation of the driving style.The longitudinal control of a vehicle is investigated in this study.The normalization task can be considered as mapping of the driving behavior in a different environment to the uniform condition.Unlike the model-based approach as in previous work,where a necessary driver model is employed to conduct the driving cycle test,the approach we propose directly normalizes the driving behavior using an autoencoder(AE)when following a standard speed profile.To ensure a positive correlation between the vehicle speed and driving behavior,a gate constraint is imposed in between the encoder and decoder to form a gated AE(gAE).This approach is model-free and efficient.The proposed approach is tested for consistency with the model-based approach and for its applications to quantitative evaluation of the driving behavior and fuel consumption analysis.Simulations are conducted to verify the effectiveness of the proposed scheme.

关键词： Driving behavior Normalization Gated auto-encoder Quantitative evaluation

Effect of proppant sizes and injection modes on proppant transportation and distribution in the tortuous fracture model

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Particuology 2024年第1期84卷 261-280页

作者： Jun li Xu Han Siyuan he Mingyi Wu xin Huang Nianyin li State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500China Chongqing Industry Polytechnic College Chongqing401120China Sichuan Particles Energy and Technology Co. LtdChengdu611630China Engineering Technology Research Institute of PetroChina Southwest Oil and Gas Field Company Chengdu610017China

Particle-fluid transport and placement mechanism in tortuous fracture played a crucial role in uncon-ventional reservoirs.Currently,most studies focused on mono-size proppant with fluid transport pro-cesses in tortuous fractures.However,the mixture-size proppant with fluid movement mechanism in tortuous fracture was still uncommon.Therefore,this study designed and applied a series of experiments with a physical analog model of a tortuous fracture with 120°and 90°-angled bends and combined high-speed camera-based equipment.This experimental system was used to track different-mixture-sized proppant particle motion trajectories for a series of proppant injection schemes;The following conclu-sions were drawn from this study:1.The pile-up processes mechanism in all investigated schemes were similar and could be reduced to four main stages.2.The packing structure at both sides of the fracture wall had different variation rates,which were controlled by the mix ratio(change from 1∶1-1∶5)of proppant size.3.Some new packing patterns,such as Zebra Stripe,had occurred,controlled by the different proppant injection sequences.4.Small-sized mono-proppant(30/50 mesh)had the highest transport efficiency in the tortuous fracture,followed by the mixed-sized multi-proppant(10/20 mesh:30/50 mesh),large-sized proppant(10/20 mesh)was the worst.5.An optimized alternating in-jection mode was recommended as injecting small-sized proppant first(30/50 mesh)and followed by mixed-sized multi-proppant(10/20 mesh:30/50 mesh),which could contribute to obtaining the optimal both proppant packing height and travel distance in tortuous fracture.6.Two correlations were devel-oped for predicting the proppant packing height and transportation distance.

关键词： Tortuous fracture model Mixed-sized proppant Multi-sized proppant injection mode Proppant motion and distribution Packing mechanism

PVDF/PLA electrospun fiber membrane impregnated with metal nanoparticles for emulsion separation,surface antimicrobial,and antifouling activities

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Science China(Technological Sciences) 2023年第5期66卷 1461-1470页

作者： XIANG xin CheN DongYun li NaJun XU QingFeng li Hua he JingHui LU JianMei College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhou215123China

Although many superwetting materials have been designed for the treatment of oil-containing wastewater,separation strategies for oil-in-water systems containing bacteria have rarely been reported.herein,poly(vinylidene difluoride)-and poly(lactic acid)-blended fibrous membranes loaded with silver and copper oxide nanoparticles were successfully prepared by a two-step method of electrostatic spinning and liquid-phase synthesis.The product membrane showed excellent super-oleophilic properties in air and hydrophobicity under oil.It could separate water-in-oil emulsion systems containing surfactants with an efficiency above90%.More importantly,the nanoparticle-loaded fibers were characterized by material degradability and slowly released ions.The fibers exhibited excellent antibacterial activities against both gram-positive and-negative bacteria.This work provides a feasible strategy for water-in-oil emulsion separation and bacterial treatment of wastewater.

关键词： emulsion separation antibacterial activity electrostatic spinning Ag nanoparticles

Roles of NG2 Glia in Cerebral Small Vessel Disease

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Neuroscience Bulletin 2023年第3期39卷 519-530页

作者： Yixi he Zhenghao li Xiaoyu Shi Jing Ding xin Wang Department of Neurology Zhongshan HospitalFudan UniversityShanghai 200032China State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science Institutes of Brain ScienceFudan UniversityShanghai 200032China Institute of Neuroscience MOE Key Laboratory of Molecular NeurobiologyNMUShanghai 200433China

Cerebral small vessel disease(CSVD)is one of the most prevalent pathologic processes affecting 5%of people over 50 years of age and contributing to 45%of dementia cases.Increasing evidence has demonstrated the pathological roles of chronic hypoperfusion,impaired cerebral vascular reactivity,and leakage of the blood–brain barrier in CSVD.However,the pathogenesis of CSVD remains elusive thus far,and no radical treatment has been developed.NG2 glia,also known as oligodendrocyte precursor cells,are the fourth type of glial cell in addition to astrocytes,microglia,and oligodendrocytes in the mammalian central nervous system.Many novel functions for NG2 glia in physiological and pathological states have recently been revealed.In this review,we discuss the role of NG2 glia in CSVD and the underlying mechanisms.

关键词： NG2 glia Oligodendrocyte precursor cell Cerebral small vessel disease White matter injury

The effects of climate warming on microbe-mediated mechanisms of sediment carbon emission

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Journal of Environmental Sciences 2023年第7期129卷 16-29页

作者： Weiwei Lü Haoyu Ren Wanchang Ding he li xin Yao Xia Jiang College of Water Sciences Beijing Normal UniversityBeijing 100875China State Key Laboratory of Environmental Criteria and Risk Assessment National Engineering Laboratory of Lake Water Pollution Control and Ecological Restoration TechnologyChinese Research Academy of Environmental SciencesBeijing 100012China School of Environment and Planning University of LiaochengLiaocheng 252000China

Due to significant differences in biotic and abiotic properties of soils compared to those of sediments,the predicted underlying microbe-mediated mechanisms of soil carbon emissions in response to warming may not be applicable for estimating similar emissions from inlandwater sediments.We addressed this issue by incubating different types of sediments,(including lake,small river,and pond sediments)collected from 36 sites across the Yangtze River basin,under short-term experimentalwarming to explore the effects of climatewarming on sediment carbon emission and the underlying microbe-mediated mechanisms.Our results indicated that under climate warming Cc emissions were affected more than CH_(4) emissions,and that pond sediments may yield a greater relative contribution of CO_(2) to total carbon emissions than lake and river sediments.Warming-induced CO_(2) and CH_(4) increases involve different microbe-mediated mechanisms;Warming-induced sediment CO_(2) emissions were predicted to be directly positively driven by microbial community network modularity,which was significantly negatively affected by the quality and quantity of organic carbon and warming-induced variations in dissolved oxygen,Conversely,warminginduced sediment CH_(4) emissionswere predicted to be directly positively driven bymicrobial community network complexity,which was significantly negatively affected by warminginduced variations in pH.Our findings suggest that biotic and abiotic drivers for sediment CO_(2) and CH_(4) emissions in response to climate warming should be considered separately when predicting sediment organic carbon decomposition dynamics resulting from climate change.

关键词： Inland water sediments Temperature sensitivity Carbon emission Microbe-mediated mechanism Short-term experimental warming

Synaptic development of layer V pyramidal neurons in the prenatal human prefrontal neocortex: a Neurolucida-aided Golgi study

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Neural Regeneration Research 2020年第8期15卷 1490-1495页

作者： li-Xin He lily Wan Wei Xiang Jian-Ming li An-Hua Pan Da-Hua Lu Xiangtan Medicine and health Vocational College XiangtanHunan ProvinceChina Department of Neurology Xiangya HospitalCentral South UniversityChangshaHunan ProvinceChina Changde Vocational Technical College ChangdeHunan ProvinceChina Department of Anatomy Changsha Medical UniversityChangshaHunan ProvinceChina Department of Anatomy and Neurobiology Xiangya School of MedicineCentral South UniversityChangshaHunan ProvinceChina

The prefrontal neocortex is involved in many high cognitive functions in humans.Deficits in neuronal and neurocircuitry development in this part of the cerebrum have been associated with various neuropsychiatric disorders in adolescents and adults.There are currently little available data regarding prenatal dendrite and spine formation on projecting neurons in the human prefrontal neocortex.Previous studies have demonstrated that Golgi silver staining can identify neurons in the frontal lobe and visual cortex in human embryos.In the present study,five fetal brains,at 19,20,26,35,and 38 gestational weeks,were obtained via the body donation program at Xiangya School of Medicine,Central South University,China.Golgi-stained pyramidal neurons in layer V of Brodmann area 46 in fetuses were quantitatively analyzed using the Neurolucida morphometry system.Results revealed that somal size,total dendritic length,and branching points of these neurons increased from 26 to 38 gestational weeks.There was also a large increase in dendritic spines from 35 to 38 gestational weeks.These findings indicate that,in the human prefrontal neocortex,dendritic growth in layer V pyramidal neurons occurs rapidly during the third trimester of gestation.The use of human fetal brain tissue was approved by the Animal Ethics Committee of Xiangya School of Medicine,Central South University,China(approval No.2011-045)on April 5,2011.

关键词： Golgi staining human brain banking neurodevelopment Neurolucida neuropsychiatric disorders prefrontal cortex synaptogenesis three-dimensional reconstruction

Exit morphology and mechanical property of FDM printed PLA: influence of hot melt extrusion process

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Advances in Manufacturing 2023年第1期11卷 56-74页

作者： Yan-Hua Bian Gang Yu xin Zhao Shao-Xia li Xiu-li he Chong-xin Tian Zhi-Yong li Institute of Mechanics Chinese Academy of SciencesBeijing100190People’s Republic of China School of Engineering Science University of Chinese Academy of SciencesBeijing100049People’s Republic of China Research Institute of 3D Printing Beijing City UniversityBeijing100083People’s Republic of China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing100049People’s Republic of China

In order to study the hot melt extrusion process in fused deposition modeling(FDM),this study mainly explores the effects of printing temperature,heated block length,feeding speed on the exit morphology and mechanical properties of FDM printed Polylactic acid(PLA)samples.High-speed camera is used to capture the exit morphology of molten PLA just extruded to the nozzle.According to exit morphology,the outlet states of extruded molten material can be divided into four categories,namely,bubbled state,coherent state,expanding state,and unstable state.Tensile test results show that printing temperature,heated block length and printing speed have significant influence on tensile properties and fracture mode of FDM printed samples.When the heated block length is 15 mm and 30 mm,there is a ductile-brittle transition in fracture mode with the increase of printing speed.The printing process window under different heated block lengths and printing temperatures has been figured out and the distribution of printing process window under different printing speeds has been discussed.There is a maximum printing process window under the heated block length of 30 mm.This finding provides a frame work for performance prediction of FDM printed parts and theoretical guidance for expanding the scope of printing process window.

关键词： Fused deposition modeling(FDM) Polylactic acid(PLA) Exit morphology Tensile property Printing process window