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Analyzing the Form-Finding of a Large-Span Transversely Stiffened Suspended Cable System: A Method Considering Construction Processes
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作者 Junyu chen Yanfei Wang +2 位作者 ke chen Shiqing Huang Xiaowen Xu 《World Journal of Engineering and Technology》 2024年第2期229-244,共16页
The precise control of the shape of transversely stiffened suspended cable systems is crucial. However, existing form-finding methods primarily rely on iterative calculations that treat loads as fixed known conditions... The precise control of the shape of transversely stiffened suspended cable systems is crucial. However, existing form-finding methods primarily rely on iterative calculations that treat loads as fixed known conditions. These methods are inefficient and fail to accurately control shape results. In this study, we propose a form-finding method that analyzes the load response of models under different sag and stress levels, taking into account the construction process. To analyze the system, a structural finite element model was established in ANSYS, and geometric nonlinear analysis was conducted using the Newton-Raphson method. The form-finding analysis results demonstrate that the proposed method achieves precise control of shape, with a maximum shape error ranging from 0.33% to 0.98%. Furthermore, the relationships between loads and tension forces are influenced by the deformed shape of the structures, exhibiting significant geometric nonlinear characteristics. Meanwhile, the load response analysis reveals that the stress level of the self-equilibrium state in the transversely stiffened suspended cable system is primarily governed by strength criteria, while shape is predominantly controlled by stiffness criteria. Importantly, by simulating the initial tensioning process as an initial condition, this method solves for a counterweight that satisfies the requirements and achieves a self-equilibrium state with the desired shape. The shape of the self-equilibrium state is precisely controlled by simulating the construction process. Overall, this work presents a new method for analyzing the form-finding process of large-span transversely stiffened suspended cable system, considering the construction process which was often overlooked in previous studies. 展开更多
关键词 Cable Structure Long-Span Structure Form-Finding Analysis Finite Element Simulation Transverse Cable Stiffening System
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Morphological disruption and visual tuning alterations in the primary visual cortex in glaucoma(DBA/2J)mice 被引量:1
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作者 Yin Yang Zhaoxi Yang +9 位作者 Maoxia Lv Ang Jia Junjun Li Baitao Liao Jing’an chen Zhengzheng Wu Yi Shi Yang Xia Dezhong Yao ke chen 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第1期220-225,共6页
Glaucoma is a leading cause of irreve rsible blindness wo rldwide,and previous studies have shown that,in addition to affecting the eyes,it also causes abnormalities in the brain.However,it is not yet clear how the pr... Glaucoma is a leading cause of irreve rsible blindness wo rldwide,and previous studies have shown that,in addition to affecting the eyes,it also causes abnormalities in the brain.However,it is not yet clear how the primary visual cortex(V1)is altered in glaucoma.This study used DBA/2J mice as a model for spontaneous secondary glaucoma.The aim of the study was to compare the electrophysiological and histomorphological chara cteristics of neurons in the V1between 9-month-old DBA/2J mice and age-matched C57BL/6J mice.We conducted single-unit recordings in the V1 of light-anesthetized mice to measure the visually induced responses,including single-unit spiking and gamma band oscillations.The morphology of layerⅡ/Ⅲneurons was determined by neuronal nuclear antigen staining and Nissl staining of brain tissue sections.Eighty-seven neurons from eight DBA/2J mice and eighty-one neurons from eight C57BL/6J mice were examined.Compared with the C57BL/6J group,V1 neurons in the DBA/2J group exhibited weaker visual tuning and impaired spatial summation.Moreove r,fewer neuro ns were observed in the V1 of DBA/2J mice compared with C57BL/6J mice.These findings suggest that DBA/2J mice have fewer neurons in the VI compared with C57BL/6J mice,and that these neurons have impaired visual tuning.Our findings provide a better understanding of the pathological changes that occur in V1 neuron function and morphology in the DBA/2J mouse model.This study might offer some innovative perspectives regarding the treatment of glaucoma. 展开更多
关键词 DBA/2J DEGENERATION gamma band oscillations GLAUCOMA primary visual cortex(V1) RETINA single-unit recording tuning curve
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Linearized waveform inversion for vertical transversely isotropic elastic media:Methodology and multi-parameter crosstalk analysis
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作者 ke chen Lu Liu +5 位作者 Li-Nan Xu Fei Hu Yuan Yang Jia-Hui Zuo Le-Le Zhang Yang Zhao 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期252-271,共20页
Seismic migration and inversion are closely related techniques to portray subsurface images and identify hydrocarbon reservoirs.Seismic migration aims at obtaining structural images of subsurface geologic discontinuit... Seismic migration and inversion are closely related techniques to portray subsurface images and identify hydrocarbon reservoirs.Seismic migration aims at obtaining structural images of subsurface geologic discontinuities.More specifically,seismic migration estimates the reflectivity function(stacked average reflectivity or pre-stack angle-dependent reflectivity)from seismic reflection data.On the other hand,seismic inversion quantitatively estimates the intrinsic rock properties of subsurface formulations.Such seismic inversion methods are applicable to detect hydrocarbon reservoirs that may exhibit lateral variations in the inverted parameters.Although there exist many differences,pre-stack seismic migration is similar with the first iteration of the general linearized seismic inversion.Usually,seismic migration and inversion techniques assume an acoustic or isotropic elastic medium.Unconventional reservoirs such as shale and tight sand formation have notable anisotropic property.We present a linearized waveform inversion(LWI)scheme for weakly anisotropic elastic media with vertical transversely isotropic(VTI)symmetry.It is based on two-way anisotropic elastic wave equation and simultaneously inverts for the localized perturbations(ΔVp_(0)/Vp_(0)/Vs_(0)/Vs_(0)/,Δ∈,Δδ)from the long-wavelength reference model.Our proposed VTI-elastic LWI is an iterative method that requires a forward and an adjoint operator acting on vectors in each iteration.We derive the forward Born approximation operator by perturbation theory and adjoint operator via adjoint-state method.The inversion has improved the quality of the images and reduces the multi-parameter crosstalk comparing with the adjoint-based images.We have observed that the multi-parameter crosstalk problem is more prominent in the inversion images for Thomsen anisotropy parameters.Especially,the Thomsen parameter is the most difficult to resolve.We also analyze the multi-parameter crosstalk using scattering radiation patterns.The linearized waveform inversion for VTI-elastic media presented in this article provides quantitative information of the rock properties that has the potential to help identify hydrocarbon reservoirs. 展开更多
关键词 ELASTIC ANISOTROPY Least-squares imaging Waveform inversion Computational geophysics
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Exercise-induced adaptation of neurons in the vertebrate locomotor system
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作者 Yue Dai Yi cheng +2 位作者 Renkai Ge ke chen Liming Yang 《Journal of Sport and Health Science》 SCIE CAS CSCD 2024年第2期160-171,共12页
Vertebrate neurons are highly dynamic cells that undergo several alterations in their functioning and physiologies in adaptation to various external stimuli.In particular,how these neurons respond to physical exercise... Vertebrate neurons are highly dynamic cells that undergo several alterations in their functioning and physiologies in adaptation to various external stimuli.In particular,how these neurons respond to physical exercise has long been an area of active research.Studies of the vertebrate locomotor system’s adaptability suggest multiple mechanisms are involved in the regulation of neuronal activity and properties during exercise.In this brief review,we highlight recent results and insights from the field with a focus on the following mechanisms:(a)alterations in neuronal excitability during acute exercise;(b)alterations in neuronal excitability after chronic exercise;(c)exercise-induced changes in neuronal membrane properties via modulation of ion channel activity;(d)exercise-enhanced dendritic plasticity;and(e)exercise-induced alterations in neuronal gene expression and protein synthesis.Our hope is to update the community with a cellular and molecular understanding of the recent mechanisms underlying the adaptability of the vertebrate locomotor system in response to both acute and chronic physical exercise. 展开更多
关键词 Dendritic plasticity EXCITABILITY Exercise Ion channel modulation Neuron adaptation
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Smart Contract Vulnerability Detection Method Based on Feature Graph and Multiple Attention Mechanisms
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作者 Zhenxiang He Zhenyu Zhao +1 位作者 ke chen Yanlin Liu 《Computers, Materials & Continua》 SCIE EI 2024年第5期3023-3045,共23页
The fast-paced development of blockchain technology is evident.Yet,the security concerns of smart contracts represent a significant challenge to the stability and dependability of the entire blockchain ecosystem.Conve... The fast-paced development of blockchain technology is evident.Yet,the security concerns of smart contracts represent a significant challenge to the stability and dependability of the entire blockchain ecosystem.Conventional smart contract vulnerability detection primarily relies on static analysis tools,which are less efficient and accurate.Although deep learning methods have improved detection efficiency,they are unable to fully utilize the static relationships within contracts.Therefore,we have adopted the advantages of the above two methods,combining feature extraction mode of tools with deep learning techniques.Firstly,we have constructed corresponding feature extraction mode for different vulnerabilities,which are used to extract feature graphs from the source code of smart contracts.Then,the node features in feature graphs are fed into a graph convolutional neural network for training,and the edge features are processed using a method that combines attentionmechanismwith gated units.Ultimately,the revised node features and edge features are concatenated through amulti-head attentionmechanism.The result of the splicing is a global representation of the entire feature graph.Our method was tested on three types of data:Timestamp vulnerabilities,reentrancy vulnerabilities,and access control vulnerabilities,where the F1 score of our method reaches 84.63%,92.55%,and 61.36%.The results indicate that our method surpasses most others in detecting smart contract vulnerabilities. 展开更多
关键词 Blockchain smart contracts deep learning graph neural networks
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Wideband low-scattering metasurface with an in-band reconfigurable transparent window
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作者 朱瑛 杨维旭 +4 位作者 段坤 姜田 赵俊明 陈克 冯一军 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期334-341,共8页
Active metasurfaces with dynamically reconfigurable functionalities are highly demanded in various practical applications.Here,we propose a wideband low-scattering metasurface that can realize an in-band reconfigurabl... Active metasurfaces with dynamically reconfigurable functionalities are highly demanded in various practical applications.Here,we propose a wideband low-scattering metasurface that can realize an in-band reconfigurable transparent window by altering the operation states of the PIN diodes loaded on the structures.The metasurface is composed of a band-pass frequency selective surface(FSS)sandwiched between two polarization conversion metasurfaces(PCMs).PIN diodes are integrated into the FSS to switch the transparent window,while a checkerboard configuration is applied in PCMs for the diffusive-reflective function.A sample with 20×20 elements is designed,fabricated,and experimentally verified.Both simulated and measured results show that the in-band functions can be dynamically switched between beam-splitting scattering and high transmission by controlling the biasing states of the diodes,while low backscattering can be attained outside the passband.Furthermore,the resonant structures of FSS also play the role of feeding lines,thus significantly eliminating extra interference compared with conventional feeding networks.We envision that the proposed metasurface may provide new possibilities for the development of an intelligent stealth platform and its antenna applications. 展开更多
关键词 metasurface reconfigurable transparent window radar cross section(RCS)reduction
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Effects of integrated management on surgical outcomes and mental health of patients following endoscopic submucosal dissection
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作者 Zhu-Hua Dai Lu Xu +2 位作者 Yu Yang Xu-Ni He ke chen 《World Journal of Clinical Cases》 SCIE 2024年第20期4034-4040,共7页
BACKGROUND Endoscopic submucosal dissection(ESD)is a less invasive local treatment for diseases throughout the gastrointestinal tract.AIM To develop an integrated management protocol and analyze its effects on surgica... BACKGROUND Endoscopic submucosal dissection(ESD)is a less invasive local treatment for diseases throughout the gastrointestinal tract.AIM To develop an integrated management protocol and analyze its effects on surgical outcomes and mental health of patients after ESD.METHODS The study population consisted of patients undergoing ESD before implementation of integrated management and those undergoing ESD by the same pool of surgeons after implementation of integrated management.RESULTS The management group exhibited shortened fasting time and length of hospital stay compared to the control group(P<0.05).The management group exhibited a higher incidence rate of postoperative complications than the control group(3 cases vs 11 cases;P=0.043).The management group exhibited a lower uncertainty score for disease knowledge compared to the control group 12 h after surgery(P<0.05).The management group gave more scores on the domains of patient familiarity to the responsible nurses,professional skills of responsible nurses,and general evaluation compared to the control group.The management group had a higher total score of patient satisfaction towards the responsible nurses in term of health care than the control group(P<0.01).The management group exhibited lower Self-Rating Anxiety Scale and Self-Rating Depression Scale scores compared to the control group 12 h after surgery(P<0.01).CONCLUSION The study demonstrates that integrated management could improve surgical outcomes and mental health of patients undergoing ESD. 展开更多
关键词 Endoscopic submucosal dissection Gastrointestinal tract Hospital stay OUTCOME Mental health
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Meta-analysis of the association between chronic periodontitis and chronic kidney disease
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作者 Fu Yang cheng-Jun Shu +1 位作者 Cai-Jun Wang ke chen 《World Journal of Clinical Cases》 SCIE 2024年第22期5094-5107,共14页
BACKGROUND Many scholars have performed several clinical studies have investigated the association between chronic periodontitis(CP)and chronic kidney disease(CKD).However,there are still differences between these res... BACKGROUND Many scholars have performed several clinical studies have investigated the association between chronic periodontitis(CP)and chronic kidney disease(CKD).However,there are still differences between these research results,and there is no unified conclusion.Therefore,a systematic review is required to understand this issue fully.AIM To explore the correlation between CP and CKD.METHODS Literature on the correlation between CP and CKD,as well as the clinical attachment level(CAL)and pocket probing depth(PPD)of CKD and non-CKD,were retrieved from PubMed,Embase,the Cochrane Library,and Web of Science repositories until January 2024.After the effective data were extracted,data processing and statistics were performed using Stata 12.0.RESULTS Of the 22 studies,13 were related to CP and CKD,and 9 reported CAL and PPD in patients with CKD and healthy controls.Meta-analysis of the correlation between CP and CKD revealed that CKD probability in people with CP was 1.54 times that of healthy individuals[relative risk=1.54,95%confidence interval(CI):1.40-1.70],and CP incidence in patients with CKD was 1.98 times that of healthy individuals[overall risk(OR)=1.98,95%CI:1.53-2.57].Meta-analysis of CAL and PPD evaluations between CKD patients and healthy individuals showed that CAL and PPD levels were higher in CKD patients[standard mean difference(SMD)of CAL=0.65,95%CI:0.29-1.01;SMD of PPD=0.33,95%CI:0.02-0.63].CONCLUSION A bidirectional association exists between CP and CKD.CKD risk is increased in CP patients and vice versa.Periodontal tissue or tooth loss risks increase over time in CKD patients. 展开更多
关键词 Chronic periodontitis Chronic kidney disease CORRELATION META-ANALYSIS
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Diagnostic Value of Endoscopic Ultrasound in Staging Rectal Cancer
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作者 Linxia Liu ke chen 《Proceedings of Anticancer Research》 2024年第4期48-53,共6页
Objective:To explore the diagnostic value of endoscopic ultrasound(EUS)in the staging of rectal cancer.Methods:Fifty patients with rectal cancer,treated at the Department of Endoscopy,Cancer Hospital Affiliated to Fud... Objective:To explore the diagnostic value of endoscopic ultrasound(EUS)in the staging of rectal cancer.Methods:Fifty patients with rectal cancer,treated at the Department of Endoscopy,Cancer Hospital Affiliated to Fudan University,from March 2023 to June 2024,were selected.All patients underwent EUS and computed tomography(CT)examination within two weeks before surgery.The postoperative pathological staging was used as the standard to compare the accuracy of tumor TN staging using EUS and/or CT.Results:The accuracy rates of T and N staging by abdominal spiral CT were 72.00%and 76.00%,respectively,while those by EUS were 88.00%and 74%,respectively.There was a significant difference in the accuracy of T staging between the two methods(both P<0.05).Conclusion:EUS has high diagnostic value in the staging of rectal cancer,providing important reference information for clinicians,aiding in the development of personalized treatment plans,and assessing patient prognosis. 展开更多
关键词 Endoscopic ultrasound Rectal cancer Diagnostic value
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Community Structures of Phytoplankton with Emphasis on Toxic Cyanobacteria in an Ohio Inland Lake during Bloom Season 被引量:3
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作者 ke chen Joel Allen Jingrang Lu 《Journal of Water Resource and Protection》 2017年第11期1299-1318,共20页
The community structures of phytoplankton are important factors and indicators of lake water quality. Harmful algal blooms severely impact water supply, recreational activities and wildlife habitat. This study aimed t... The community structures of phytoplankton are important factors and indicators of lake water quality. Harmful algal blooms severely impact water supply, recreational activities and wildlife habitat. This study aimed to examine the phytoplankton composition and variations using microscopy, and identify harmful Cyanobacteria in weekly samples taken from four sites at Harsha Lake in southwest Ohio. Over the course of the summer in 2015, the phytoplankton of Harsha Lake consisted mainly of 13 taxa belonging to Bacillariophyta, Chlorophyta, Cryptophyta, Cyanobacteria, Dinophyta and Euglenophyta. Their significant successions started with Bacillariophyta and/or Chlorophyta, then bloomed with Cyanobacteria and ended with Chlorophyta and/or Dinophyta. Cyanobacteria members: Microcystis, Planktothrix, Dolichospermum, Aphanizomenon, Cylindrospermopsis, and Oscillatoria from the Cyanophyceae were identified to be dominant genera. These organisms varied spatially and temporally in similar patterns along with the variations of nutrients and formed the summer bloom with the total biomasses ranging from 0.01 to 114.89 mg L-1 with mean of 22.88 mg L-1. M. aeruginosa and P. rubescens were revealed as the microcystin producers, while A. circinalis and Aphanizomenon sp. were identified as a saxitoxin producer through cloning and sequencing PCR products of mcyA, mcyE and sxtA genes. The biomasses of phytoplankton, Cyanobacteria and Microcystis were positively correlated to nutrients, especially to total nitrogen. The total ELISA measurement for microcystin positively correlated with Cyanobacteria (R2 = 0.66, P Microcystis (R2 = 0.64, P 2 = 0.59, P < 0.0001). The basic information on the occurrence and biomasses of Cyanobacteria and total phytoplankton, and the analysis for toxic species, which were the first report for the inland water in Ohio, USA, will document the succession patterns of phytoplankton and toxin production over a season and provide data to predict risk occurrence to both human and ecological factors. 展开更多
关键词 PHYTOPLANKTON CYANOBACTERIA BLOOM TOXIN PRODUCER Lake
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Efficient polysulfide blocker from conductive niobium nitride@graphene for Li-S batteries 被引量:1
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作者 Huifa Shi Zhenhua Sun +8 位作者 Wei Lv Shujie Xiao Huicong Yang Ying Shi ke chen Shaogang Wang Bingsen Zhang Quan-Hong Yang Feng Li 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2020年第6期135-141,I0006,共8页
Lithium sulfur batteries are one of the most promising alternative electrochemical systems,but their practical applications are largely hindered by the serious shuttling problems and sluggish redox kinetics.Here,the c... Lithium sulfur batteries are one of the most promising alternative electrochemical systems,but their practical applications are largely hindered by the serious shuttling problems and sluggish redox kinetics.Here,the conductive and polar niobium nitride(NbN)is in-situ introduced onto graphene with ultrasmall size and high dispersion,and their composite is used to construct an efficient lithium polysulfide blocking layer.The graphene helps to construct highly conductive pathways,and niobium nitride serves as the sulfiphilic sites to chemically adsorb the migrating lithium polysulfides and catalyze their redox conversion.Hence,the cells with the Nb N/G interlayers exhibit a long cycle life with a lower capacity decay of 0.096%/cycle at 1 C for 300 cycles and high rate capability of 937 m Ah g^-1 at 2 C.Further coupling with a sulfur/carbon nanofiber electrode,the cell with an ultra-high sulfur loading of 10.8 mg cm^-2 delivers an areal capacity of 12.5 m Ah cm^-2 at 0.1 C. 展开更多
关键词 Lithium-sulfur BATTERIES NIOBIUM NITRIDE Chemical adsorption Catalytic effect High loading
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A Two-Party Password-Authenticated Key Exchange Protocol with Verifier
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作者 Shunbo Xiang Bing Xu ke chen 《Journal of Computer and Communications》 2021年第4期102-109,共8页
To tackle with the security lack in the password-authenticated key exchange protocol, this paper proposes a two-party password-authenticated key exchange protocol based on a verifier. In the proposed protocol, a user ... To tackle with the security lack in the password-authenticated key exchange protocol, this paper proposes a two-party password-authenticated key exchange protocol based on a verifier. In the proposed protocol, a user stores his password in plaintext, and the server stores a verifier for the user’s password, using DL difficult problem and DH difficult problem, through the session between user and server to establish a session key. The security discussion result shows that the proposed protocol provides forward secrecy, and can effectively defend against server compromising fake attacks, dictionary attacks and middleman attacks. Protocol efficiency comparisons reveal our protocol is more reasonable. 展开更多
关键词 VERIFIER Password-Authenticated Key Exchange Fake Attack Dictionary Attack Session Key
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国外需求促进了中国出口企业创新吗? 被引量:3
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作者 朱海 陈柯 韩清 《产业经济评论》 2023年第3期115-127,共13页
本文运用详细的海关数据构建了中国出口企业面临的国外需求指标,并进一步按目的国类型与贸易方式细分,研究了国外需求与中国出口企业创新之间的关系。结果表明:总体上,来自发达国家的需求显著抑制了中国出口企业的创新。异质性分析表明... 本文运用详细的海关数据构建了中国出口企业面临的国外需求指标,并进一步按目的国类型与贸易方式细分,研究了国外需求与中国出口企业创新之间的关系。结果表明:总体上,来自发达国家的需求显著抑制了中国出口企业的创新。异质性分析表明,国外需求与出口企业创新的关系在不同要素密集度以及不同所有制企业中表现各有不同。在发达国家的需求中,加工贸易是抑制中国出口企业创新的重要原因。在一般贸易方式下,来自发达国家与发展中国家的“需求引致创新”效应依然有效,体现为,发达国家的需求对中国出口企业创新的影响偏向于过程创新,而发展中国家的需求对中国出口企业创新的影响偏向于产品创新。本文为中国当前的双循环发展战略调整提供了有价值的参考依据。 展开更多
关键词 国外需求 加工贸易 一般贸易 过程创新 产品创新
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Targeted mechanical forces enhance the effects of tumor immunotherapy by regulating immune cells in the tumor microenvironment 被引量:3
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作者 Pengfei Zhu Hongrui Lu +3 位作者 Mingxing Wang ke chen Zheling chen Liu Yang 《Cancer Biology & Medicine》 SCIE CAS CSCD 2023年第1期44-55,共12页
Mechanical forces in the tumor microenvironment(TME)are associated with tumor growth,proliferation,and drug resistance.Strong mechanical forces in tumors alter the metabolism and behavior of cancer cells,thus promotin... Mechanical forces in the tumor microenvironment(TME)are associated with tumor growth,proliferation,and drug resistance.Strong mechanical forces in tumors alter the metabolism and behavior of cancer cells,thus promoting tumor progression and metastasis.Mechanical signals are transformed into biochemical signals,which activate tumorigenic signaling pathways through mechanical transduction.Cancer immunotherapy has recently made exciting progress,ushering in a new era of“chemo-free”treatments.However,immunotherapy has not achieved satisfactory results in a variety of tumors,because of the complex tumor microenvironment.Herein,we discuss the effects of mechanical forces on the tumor immune microenvironment and highlight emerging therapeutic strategies for targeting mechanical forces in immunotherapy. 展开更多
关键词 Mechanical force MICROENVIRONMENT IMMUNOTHERAPY extracellular matrix cancer
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陕西省小蚕人工饲料共育技术现状、问题与对策 被引量:1
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作者 柯琛 陈贵攀 +3 位作者 陈佳 刘晓 陈正余 谢进军 《北方蚕业》 2023年第3期46-49,共4页
总结陕西省近年来人工饲料小蚕共育的推广现状及成功经验,分析了蚕农人工饲料养蚕认识不到位、小蚕共育温湿度控制不标准、人工饲料适应性蚕品种少、发生小蚕等问题及其原因,提出了加快品种选育、建立饲料配送中心、加强技术培训、给以... 总结陕西省近年来人工饲料小蚕共育的推广现状及成功经验,分析了蚕农人工饲料养蚕认识不到位、小蚕共育温湿度控制不标准、人工饲料适应性蚕品种少、发生小蚕等问题及其原因,提出了加快品种选育、建立饲料配送中心、加强技术培训、给以资金扶持等对策和建议。 展开更多
关键词 人工饲料 小蚕共育 现状 对策
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Influence of Cavitation on Unsteady Vortical Flows in a Side Channel Pump
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作者 Yefang Wang Fan Zhang +3 位作者 Shouqi Yuan ke chen Feng Hong Desmond Appiah 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2023年第1期171-189,共19页
Previous investigation on side channel pump mainly concentrates on parameter optimization and internal unsteady vortical flows.However,cavitation is prone to occur in a side channel pump,which is a challenging issue i... Previous investigation on side channel pump mainly concentrates on parameter optimization and internal unsteady vortical flows.However,cavitation is prone to occur in a side channel pump,which is a challenging issue in promoting performance.In the present study,the cavitating flow is investigated numerically by the turbulence model of SAS combined with the Zwart cavitation model.The vapors inside the side channel pump firstly occur in the impeller passage near the inlet and then spread gradually to the downstream passages with the decrease of NPSHa.Moreover,a strong adverse pressure gradient is presented at the end of the cavity closure region,which leads to cavity shedding from the wall.The small scaled vortices in each passage reduce significantly and gather into larger vortices due to the cavitation.Comparing the three terms of vorticity transport equation with the vapor volume fraction and vorticity distributions,it is found that the stretching term is dominant and responsible for the vorticity production and evolution in cavitating flows.In addition,the magnitudes of the stretching term decrease once the cavitation occurs,while the values of dilatation are high in the cavity region and increase with the decreasing NPSHa.Even though the magnitude of the baroclinic torque term is smaller than vortex stretching and dilatation terms,it is important for the vorticity production along the cavity surface and near the cavity closure region.The pressure fluctuations in the impeller and side channel tend to be stronger due to the cavitation.The primary frequency of monitor points in the impeller is 24.94 Hz and in the side channel is 598.05 Hz.They are quite corresponding to the shaft frequency of 25 Hz(fshaft=1/n=25 Hz)and the blade frequency of 600 Hz(fblade=Z/n=600 Hz)respectively.This study complements the investigation on cavitation in the side channel pump,which could provide the theoretical foundation for further optimization of performance. 展开更多
关键词 Side channel pump Vortical flows CAVITATION Vortex-cavitation interaction Pressure fluctuation
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Extracting angle-domain common-image gathers in VTI media using ansiotropic-Helmholtz P/S wave-mode decomposition
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作者 Le-Le Zhang Yang Zhao +4 位作者 Lu Liu ke chen Jia-Hui Zuo Yi-Xin Wang Ji-Dong Yang 《Petroleum Science》 SCIE EI CAS CSCD 2023年第3期1546-1561,共16页
Common-image gathers are extensively used in amplitude versus angle(AVA)and migration velocity analysis(MVA).The current state of methods for anisotropic angle gathers extraction use slant-stack,local Fourier transfor... Common-image gathers are extensively used in amplitude versus angle(AVA)and migration velocity analysis(MVA).The current state of methods for anisotropic angle gathers extraction use slant-stack,local Fourier transform or low-rank approximation,which requires much computation.Based on an anisotropic-Helmholtz P/S wave-mode decomposition method,we propose a novel and efficient approach to produce angle-domain common-image gathers(ADCIGs)in the elastic reverse time migration(ERTM)of VTI media.To start with,we derive an anisotropic-Helmholtz decomposition operator from the Christoffel equation in VTI media,and use this operator to derive the decomposed formulations for anisotropic P/S waves.Second,we employ the first-order Taylor expansion to calculate the normalized term of decomposed formulations and obtain the anisotropic-Helmholtz decomposition method,which generates the separated P/S wavefields with correct amplitudes and phases.Third,we develop a novel way that uses the anisotropic-Helmholtz decomposition operator to define the polari-zation angles for anisotropic P/S waves and substitute these angles to decomposing formulations.The polarization angles are then calculated directly from the separated vector P-and S-wavefields and converted to the phase angles.The ADCIGs are thusly produced by applying the phase angles to VTI ERTM.In addition,we develop a concise approximate expression of residual moveout(RMO)for PP-reflections of flat reflectors in VTI media,which avoids the complex transformations between the group angles and the phase angles.The approximate RMO curves show a good agreement with the exact solution and can be used as a tool to assess the migration velocity errors.As demonstrated by two selected examples,our ADCIGs not only produce the correct kinematic responses with regards to different velocity pertubatation,but also generate the reliable amplitude responses versus different angle.The final stacking images of ADCIGs data exhibit the identical imaging effect as that of VTI ERTM. 展开更多
关键词 Helmholtz decomposition Angle gathers Anisotropy Elastic-RTM
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Advanced biosensing technologies for monitoring of agriculture pests and diseases:A review
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作者 Jiayao He ke chen +2 位作者 Xubin Pan Junfeng Zhai Xiangmei Lin 《Journal of Semiconductors》 EI CAS CSCD 2023年第2期57-65,共9页
The threat posed to crop production by pests and diseases is one of the key factors that could reduce global food security.Early detection is of critical importance to make accurate predictions,optimize control strate... The threat posed to crop production by pests and diseases is one of the key factors that could reduce global food security.Early detection is of critical importance to make accurate predictions,optimize control strategies and prevent crop losses.Recent technological advancements highlight the opportunity to revolutionize monitoring of pests and diseases.Biosensing methodologies offer potential solutions for real-time and automated monitoring,which allow advancements in early and accurate detection and thus support sustainable crop protection.Herein,advanced biosensing technologies for pests and diseases monitoring,including image-based technologies,electronic noses,and wearable sensing methods are presented.Besides,challenges and future perspectives for widespread adoption of these technologies are discussed.Moreover,we believe it is necessary to integrate technologies through interdisciplinary cooperation for further exploration,which may provide unlimited possibilities for innovations and applications of agriculture monitoring. 展开更多
关键词 precision agriculture biosensors CROPS disease and pest management
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Correlation analysis of longitudinal cracks and vertical deformation within asphalt pavement of cold regions
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作者 ke chen Lun Ji +3 位作者 ZeYu Xiao JinQi Wu LinLin Xu ZhiCe cheng 《Research in Cold and Arid Regions》 CSCD 2023年第6期278-287,共10页
The asphalt pavement longitudinal crack is a common distress in cold regions,resulting from uneven deformation of the subgrade.Analysis of the correlation law between uneven deformation and crack distress is of positi... The asphalt pavement longitudinal crack is a common distress in cold regions,resulting from uneven deformation of the subgrade.Analysis of the correlation law between uneven deformation and crack distress is of positive significance for understanding the mechanism of crack initiation,and putting forward treatment measures.In view of the complexity of longitudinal crack inducement and road surface deformation,the grey relational method was used to analyze this relationship.Through long-term monitoring of the vertical deformation data of typical road sections,the vertical deformation law of the pavement surface and its deformation characteristics under the action of temperature field are analyzed.Parameters such as vertical relative deformation,vertical relative deformation rate and vertical differential deformation VDSr were constructed to describe vertical deformation characteristics.Typical distribution characteristics of longitudinal fractures and their length and distribution characteristics are also described.The grey correlation analysis theory was utilized to analyze the relationship between deformation characteristics of sections,cross sections and monitoring points and longitudinal crack characteristics(length and location).The analysis reveals a linear positive correlation or a high correlation between several indicators.This study can provide a deeper understanding of the occurrence and development mechanism of longitudinal cracks in asphalt pavement of cold areas,and give references for the research of road engineering structure,materials and distress prevention. 展开更多
关键词 Asphalt pavement Cold region Longitudinal crack Vertical deformation Grey relational analysis
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Efficacy of tibial transverse transport combined with platelet-rich plasma versus platelet-rich plasma alone in the treatment of diabetic foot ulcers:A meta-analysis
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作者 ke chen Yikang Yu +3 位作者 Jialu Shu Binbin Zhang Gang Wang Bin Wu 《Chinese Journal of Plastic and Reconstructive Surgery》 2023年第3期145-153,共9页
Background:Diabetic foot ulcers(DBFU)are one of the main complications of diabetes.Platelet-rich plasma(PRP)treatment is a commonly used treatment option.Tibial transverse transport(TTT)also has a therapeutic effect o... Background:Diabetic foot ulcers(DBFU)are one of the main complications of diabetes.Platelet-rich plasma(PRP)treatment is a commonly used treatment option.Tibial transverse transport(TTT)also has a therapeutic effect on DBFU.Some studies have found that the TTT combined with PRP(TTT&PRP)has a significant effect on DBFU.Methods:PubMed,Cochrane Library,Web of Science,EMBASE,Chinese Biomedical Literature,CNKI,VIP,and Wanfang databases were used to find literature on the treatment of DBFUs using the TTT and PRP treatment according to the inclusion criteria.The specific inclusion criteria are as follows:(1)research type:clinical controlled trials,including retrospective cohort and randomized controlled studies;(2)diagnosis of DBFUs that does not include a definitively diagnosed traumatic ulcer;(3)original materials of Chinese and English literature published in full text.The exclusion criteria are:(1)the research group was not defined or grouped;(2)nonrandomized controlled trials,non-cohort studies,non-case-control studies,retrospective studies,and case reports;(3)repetitive research and animal experimentation;(4)ulcers caused by other diseases;(5)conservative treatment or no use of invasive treatment methods.Review Manager software(version 5.3)was used to conduct a meta-analysis of the included results.Result:The literature included 6 randomized controlled studies,including 508 patients,254 patients in the PRP treatment group,and 254 patients in the TTT&PRP group.The meta-analysis results showed that in terms of treatment efficacy,the TTT&PRP combined treatment group had a higher efficacy than the PRP group.After treatment,the TTT&PRP group had better treatment effects in psychological function,physiological function,and social function compared to the PRP group.After treatment,the TTT&PRP group showed a significant increase in serum epidermal growth factor(EGF),vascular endothelial growth factor(VEGF),basic fibroblast growth factor(bFGF),and platelet-derived growth factor(PDGF)levels compared to the PRP group.In terms of wound healing after treatment,the TTT&PRP group performed better than the PRP group in terms of postoperative wound reduction rate,bacterial clearance rate,granulation tissue coverage rate,and granulation tissue growth thickness.Conclusion:TTT combined with PRP was more effective than PRP alone in treating DBFUs. 展开更多
关键词 Tibial transverse transport Platelet-rich plasma Diabetic foot ulcer Growth factor META-ANALYSIS
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