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Performance optimization of thermionic refrigerators based on van der Waals heterostructures

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Science China(Technological Sciences) 2021年第5期64卷 1007-1016页

作者： qiu SuSu DING ZeMin chen LinGen GE YanLin Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China School of Mechanical&Electrical Engineering Wuhan Institute of TechnologyWuhan 430205China College of Power Engineering Naval University of EngineeringWuhan 430033China

In this paper, an irreversible thermionic refrigerator model based on van der Waals heterostructure with various irreversibilities is established by utilizing combination of non-equilibrium thermodynamics and finite time thermodynamics. The basic performance characteristics of the refrigerator are obtained. The effects of key factors, such as bias voltages, Schottky barrier heights and heat leakages, on the performance are studied. Results show that cooling rates and coefficients of performances(COPs) can attain the double maximum with proper modulation of barrier heights and bias voltages. Increasing cross-plane thermal resistance as well as decreasing electrode-reservoir thermal resistance and reservoir-reservoir thermal resistance can enhance the performance of the device. The optimal performance region is the interval between the maximum cooling rate point and the maximum COP point. By modulating the bias voltage, the working state of the device can fall into the optimal performance region. The optimal performance of the refrigerator when using single layer graphene and a few layers graphene as electrode material is also compared.

关键词： thermionic refrigerator van der Waals heterostructure cooling rate COP performance optimization finite time thermodynamics

Systematic Review on Wearable Lower Extremity Robotic Exoskeletons for Assisted Locomotion

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Journal of Bionic Engineering 2023年第2期20卷 436-469页

作者： Shuang qiu Zhongcai Pei chen Wang Zhiyong Tang School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Lower extremity robotic exoskeletons(LEEX)can not only improve the ability of the human body but also provide healing treatment for people with lower extremity *** are a wide range of application needs and development prospects in the military,industry,medical treatment,consumption and other felds,which has aroused widespread concern in *** paper attempts to review LEEX technical ***,the history of LEEX is briefy ***,based on existing research,LEEX is classifed according to auxiliary body parts,structural forms,functions and felds,and typical LEEX prototypes and products are ***,the latest key technologies are analyzed and summarized,and the research contents,such as bionic structure and driving characteristics,human–robot interaction(HRI)and intentawareness,intelligent control strategy,and evaluation method of power-assisted walking efciency,are described in ***,existing LEEX problems and challenges are analyzed,a future development trend is proposed,and a multidisciplinary development direction of the key technology is provided.

关键词： Lower extremity robotic exoskeletons Bionic robot Classifcation method Human-robot interaction Biomechatronic

Inkjet Printing of Single-Walled Carbon Nanotube/RuO_(2) Nanowire Supercapacitors on Cloth Fabrics and Flexible Substrates

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Nano Research 2010年第8期3卷 594-603页

作者： Pochiang chen Haitian chen Jing qiu Chongwu Zhou Chemical Engineering Department and Materials Science University of Southern CaliforniaLos AngelesCalifornia 90089USA Department of Electrical Engineering University of Southern CaliforniaLos AngelesCalifornia 90089USA

Single-walled carbon nanotube(SWNT)thin film electrodes have been printed on flexible substrates and cloth fabrics by using SWNT inks and an off-the-shelf inkjet printer,with features of controlled pattern geometry(0.4-6 cm^(2)),location,controllable thickness(20-200 nm),and tunable electrical *** as-printed SWNT films were then sandwiched together with a piece of printable polymer electrolyte to form flexible and wearable supercapacitors,which displayed good capacitive behavior even after 1,000 charge/discharge ***,a simple and efficient route to produce ruthenium oxide(RuO_(2))nanowire/SWNT hybrid films has been developed,and it was found that the knee frequency of the hybrid thin film electrodes can reach 1,500 Hz,which is much higher than the knee frequency of the bare SWNT electrodes(~158 Hz).In addition,with the integration of RuO_(2) nanowires,the performance of the printed SWNT supercapacitor was significantly improved in terms of its specific capacitance of 138 F/g,power density of 96 kW/kg,and energy density of 18.8 Wh/*** results indicate the potential of printable energy storage devices and their significant promise for application in wearable energy storage devices.

关键词： Nanowires carbon nanotubes supercapacitors printed and wearable energy devices

Molecular transformation of dissolved organic matter in refinery wastewaters: Characterized by FT-ICR MS coupled with electrospray ionization and atmospheric pressure photoionization

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Petroleum Science 2023年第1期20卷 590-599页

作者： chen He Wei-Ming chen chun-Mao chen Quan Shi State Key Laboratory of Heavy Oil Processing Beijing Key Laboratory of Oil and Gas Pollution ControlChina University of PetroleumBeijing 102249China Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengduSichuan 611756China

Dissolved organic matter(DOM)in refinery wastewater is an extremely complex mixture of various organic *** mass spectrometry,it is impossible to characterize all of the DOM molecules with only one ionization *** this study,negative-ion,electrospray ionization(ESI),positive-ion ESI,and positive-ion atmospheric pressure photoionization(APPI)were coupled with Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR MS)to analyze the molecular composition of DOM in a refinery wastewater stream during the treatment *** were obvious differences in the heteroatom composition,number of DOM constituents,and chemical properties in refinery wastewater under the three ionization *** CHO and CHOS compounds detected by(+)ESI,basic CHN and CHON compounds detected by(þ)ESI,and hydrocarbons detected by(+)APPI were analyzed to determine the molecular transformations that occurred during *** an anaerobic biological treatment process,acidic CHO and CHOS compounds with a high oxygen content were preferentially removed,and acidic CHO and CHOS compounds with a low oxygen content were *** an aerobic biological process,acidic CHO and CHOS compounds with a low oxygen content were preferentially removed,and acidic CHO and CHOS compounds with a high oxygen content were *** whole biological treatment process has a poor removal efficiency for CHN and CHON compounds,and *** activated carbon(AC)adsorption process removed different heteroatom compounds mainly with a low oxygen content for acidic and basic *** transformation mechanism of CHO and CHOS compounds in the biological treatment process was analyzed by the Kendrick mass defect(KMD)theory and a mass difference network *** the anaerobic process,large amounts of oxygenated CHO and CHOS compounds were degraded by decarboxylation,deoxydation,demethoxylation,and dehydration reactions,and converted to lower oxygen content *** the aerobic

关键词： Refinery wastewater DOM Molecular transformation ESI APPI FT-ICR MS

Recent progress in nanomaterial-enhanced fluorescence polarization/anisotropy sensors

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Chinese Chemical Letters 2019年第9期30卷 1575-1580页

作者： Jia chen Juewen Liu Xingguo chen Hongdeng qiu CAS Key Laboratory of Chemistry of Northwestern Plant Resources and Key Laboratory for Natural Medicine of Gansu Province Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 China University of Chinese Academy of Sciences Chinese Academy of Sciences Beijing 10039 China Department of Chemistry Waterloo Institute for Nanotechnology University of Waterloo Waterloo Ontario N2L 3G1 Canada State Key Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou 730000 China

As a promising signaling transduction approach, fluorescence polarization(FP)/fluorescence anisotropy(FA), provides a powerful quantitative tool for the rotational motion of fluorescently labeled molecules in chemical or biological homogeneous systems. Unlike fluorescence intensity, FP/FA is almost independent the concentration or quantum of fluorophores, but they are highly dependent on the size or molecular weight of the molecules or materials attached to fluorophores. Recently, significant progress in FP/FA was made, due to the introduction of some nanomaterials as FP/FA enhancers. The detection sensitivity is thus greatly improved by using nanomaterials as FP/FA enhancers, and nanomaterial-based FP/FA is currently used successfully in immunoassay, and analysis of protein, nucleic acid, small molecule and metal ***-based FP/FA provides a new kind of strategy to design fluorescent sensors and establishes innovative analytical methods. In this review, we summarize the scientific publications in the field of FP/FA sensor in recent five years, and first introduce the recent progress of FP/FA sensor based on nanomaterial. Subsequently, the various analytical applications of FP/FA based on nanomaterial are discussed. Finally, we provide perspectives on the current challenges and future prospects in this promising field.

关键词： Fluorescence polarization/anisotropy Nanomaterials Sensor Recent progress Application

Preoperational diagnosis and management of breast ductal carcinoma in situ arising within fibroadenoma:Two case reports

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World Journal of Clinical Cases 2022年第11期10卷 3496-3504页

作者： Jun Wu Ke-Wang Sun qiu-Ping Mo Ze-Ran Yang Yuan chen Miao-chun Zhong Department of Breast Surgery Zhejiang Provincial People’s HospitalPeople’s Hospital of Hangzhou Medical CollegeHangzhou 310014Zhejiang ProvinceChina Cancer Center Zhejiang Provincial People’s HospitalPeople’s Hospital of Hangzhou Medical CollegeHangzhou 310014Zhejiang ProvinceChina Department of Pathology Zhejiang Provincial People’s Hospital

BACKGROUND Ductal carcinoma in situ(DCIS)arising within fibroadenoma is a type of tumor that is rarely encountered in clinic,with only about 100 cases of carcinoma arising within a fibroadenoma reported in the ***,we present two cases of breast DCIS arising within a fibroadenoma and discuss their clinical and imaging findings as well as *** SUMMARY The patients did not have cancer-related personal and family *** 1(a 49-year-old woman)was diagnosed with a bilateral breast nodule in May 2018 and was followed(preoperative imaging data including ultrasound and mammography)for 3 years;she underwent an excisional biopsy to address an enlargement in nodule *** 2(a 37-year-old woman)was diagnosed with a left breast nodule in June 2021 and consequently received vacuum-assisted biopsy of the tumor which appeared as“irregularly shaped”and“unevenly textured”tissue on *** pathological diagnosis was clear in both *** patients underwent breast-conserving surgery and sentinel lymph node *** two cases received or planned to receive radiotherapy as well as endocrine therapy(tamoxifen).CONCLUSION Breast DCIS arising within a fibroadenoma is rare,but patients treated with radiotherapy and endocrine therapy can have good prognosis.

关键词： Fibroadenoma Ductal carcinoma in situ Vacuum-assisted biopsy Excisional biopsy Case report

CONVERGENCE ANALYSIS OF MORLEY ELEMENT ON ANISOTROPIC MESHES

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Journal of Computational Mathematics 2006年第2期24卷 169-180页

作者： Shi-peng Mao Shao-chun chen ICMSEC Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing 100080 China Department of Mathematics Zhengzhou University Zhengzhou 450052 China

The main aim of this paper is to study tile convergence of a nonconforming triangular plate element-Morley element under anisotropic meshes. By a novel approach, an explicit bound for the interpolation error is derived for arbitrary triangular meshes （which even need not satisfy the maximal angle condition and the coordinate system condition ）, the optimal consistency error is obtained for a family of anisotropically graded finite element meshes.

关键词： Anisotropic meshes Interpolation error Consistency error Morley element.

Western blotting in the diagnosis of duodenal-biliary and pancreaticobiliary refluxes in biliary diseases

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Hepatobiliary & Pancreatic Diseases International 2009年第6期8卷 608-613页

作者： chun-Chih chen Department of General Surgery Shengjing HospitalChina Medical University

BACKGROUND: Currently adopted diagnostic methods for duodenal-biliary and pancreaticobiliary refluxes carry many flaws, so the incidence of the two refluxes demands further larger sample size studies. This study aimed to evaluate Western blotting for the diagnosis of refluxes in biliary diseases. METHODS: An oral radionuclide (99)mTc-DTPA test (radionuclide, RN) was conducted for the observation of duodenal-biliary reflux prior to measuring bile radioactivity and Western blotting for detecting bile enterokinase (EK). Pancreaticobiliary reflux was assessed by biochemical and Western blotting tests for biliary amylase activity and trypsin-1, respectively. In accordance with bile sample origin, our samples were classified into ductal bile and gall bile groups; based on each individual biliary disease, we further classified the ductal bile group into five subgroups, and the gall bile group into four sub-groups. Western blotting was conducted to assess the two refluxes in biliary diseases. RESULTS: Consistencies were noted between EK and RN tests when diagnosing duodenal-biliary reflux (P0.05); in the common bile duct cyst group, the EK positive rate was significantly lower than the trypsin-1 positive rate (P<0.05). CONCLUSIONS: Western blotting can accurately reflect duodenal-biliary and pancreaticobiliary refluxes. EK has greater sensitivity than RN for duodenal-biliary reflux. The majority of biliary amylase and lipase comes from the pancreas in all biliary diseases; pancreaticobiliary reflux is the predominant source in the common bile duct cyst group and duodenal-biliary reflux is responsible for the ductal pigment stone group.

关键词： pancreaticobiliary reflux duodenal-biliary reflux trypsin-1 enterokinase biliary diseases

Advanced Feature Fusion Algorithm Based on Multiple Convolutional Neural Network for Scene Recognition

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Computer Modeling in Engineering & Sciences 2020年第2期122卷 505-523页

作者： Lei chen Kanghu Bo Feifei Lee qiu chen School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China. Algorithm Department UnisocShanghai201203China. Major of Electrical Engineering and Electronics Graduate School of EngineeringKogakuin UniversitySinjuku-kuTokyo163-8677Japan.

Scene recognition is a popular open problem in the computer vision *** lots of methods proposed in recent years,Convolutional Neural Network(CNN)based approaches achieve the best performance in scene *** propose in this paper an advanced feature fusion algorithm using Multiple Convolutional Neural Network(Multi-CNN)for scene *** existing works that usually use individual convolutional neural network,a fusion of multiple different convolutional neural networks is applied for scene ***,we split training images in two directions and apply to three deep CNN model,and then extract features from the last full-connected(FC)layer and probabilistic layer on each ***,feature vectors are fused with different fusion strategies in groups forwarded into SoftMax *** proposed algorithm is evaluated on three scene datasets for scene *** experimental results demonstrate the effectiveness of proposed algorithm compared with other state-of-art approaches.

关键词： Scene recognition deep feature fusion multiple convolutional neural network.