检索结果-南通市图书馆

Integral precession calibration method of PIGA on linear vibration table

Chinese Journal of Aeronautics 2024年第3期37卷 219-236页

作者： Chuang SUN Shun-qing REN jun-wei CAO Ru HUO Department of Automation Tsinghua UniversityBeijing 100084China School of Astronautics Harbin Institute of TechnologyHarbin 150001China Beijing National Research Center for Information Science and Technology Tsinghua UniversityBeijing 100084China Faculty of Information technology Beijing University of TechnologyBeijing 100124China

Linear vibration table can provide harmonic accelerations to excite the nonlinear error terms of Pendulous Integrating Gyro Accelerometer(PIGA).Integral precession calibration method is proposed to calibrate PIGA on a linear vibration table in this *** on the precise expressions of PIGA’s inputs,the error calibration model of PIGA is *** angular velocity errors of PIGA are suppressed by integer periodic precession and the errors caused by non-integer periods vibrating are *** complete calibration process,including planning,preparation,PIGA testing,and coefficient identification,is designed to optimize the test operations and evaluate the calibration *** effect of the main errors on calibration uncertainty is analyzed and the relative sensitivity function is proposed to further optimize the test *** and simulation results verify that the proposed 10-position calibration method can improve calibration uncertainties after compensating for the related *** order of calibration uncertainties of the second-and third-order coefficients are decreased to 10^(-8)(rad.s^(-1))/g^(2)and 10^(-8)(rad.s^(-1))/g3,*** with the other two classical calibration methods,the calibration uncertainties of PIGA’s nonlinear error coefficients can be effectively reduced and the proportional residual errors are decreased less than 3×10-6(rad.s^(-1))/g by using the proposed calibration method.

关键词： PIGA Linear vibration table Vibration measurement Calibration Error analysis Uncertainty analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Characterization of Fe-containing particles in Chengdu,southwest China,using single-particle aerosol mass spectrometry

引用

Journal of Environmental Sciences 2024年第2期136卷 110-120页

作者： Renjiang He junke zhang Luyao Chen wei zhang Yingwei Xi School of Public Health Southwest Medical UniversityLuzhou 646000China Faculty of Geosciences and Environmental Engineering Southwest Jiaotong UniversityChengdu 611756China Sichuan Environmental Monitoring Center Chengdu 610074China

Single-particle aerosol mass spectrometry was used to study the characteristics of Fecontaining particles during winter in Chengdu,southwest *** mass concentrations of PM_(2.5)and PM_(10)during the study period were 64±38 and 89±49μg/m~3,respectively,and NO_(2)and particulate matter were high compared with most other regions of *** Fecontaining particles were divided into seven categories with different mass spectra,sources and aging *** highest contribution was from Fe mixed with carbonaceous components(Fe-C,23.1%)*** was more mixed with sulfate than nitrate and therefore the contribution of Fe mixed with sulfate(Fe-S,20.7%)particles was higher than that of Fe mixed with nitrate(Fe-N,12.5%)*** contributions from Fe-containing particles related to primary combustion were high in the small particle size range,whereas aged Fecontaining particles and dust-related particles were mostly found in the coarse particle size *** air masses mainly originated from the west and east of Chengdu,and the corresponding PM_(2.5)concentrations were 79±36 and 55±36μg/m~3,*** west and east air masses showed stronger contributions of Fe-containing particles related to biomass burning(Fe-B)and fossil fuel combustion(Fe-C and Fe-S)particles,*** southwest area contributed the most Fe-containing *** assessments of the effects of Fe-containing particles during heavy pollution period should pay more attention to Fe-C and Fe-S ***-reduction of Fe-containing particles should consider both local emissions and short-distance transmission from the surrounding areas.

关键词： Fe-containing particles Particle composition Potential source areas Evolution Chengdu

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Optimal Planning of Hybrid AC/DC Low-voltage Distribution Networks Considering DC Conversion of Three-phase Four-wire Low-voltage AC Systems

引用

Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 141-153页

作者： Bo zhang Lu zhang wei Tang Gen Li Chen Wang the College of Information and Electrical Engineering China Agricultural UniversityBeijing 100083China the Electric Energy Group Department of Engineering TechnologyTechnical University of Denmark(DTU)2750 BallerupDenmark the Power Distribution Technology Center State Grid Beijing Electric Power Research InstituteBeijing 100075China

The increasing integration of distributed household photovoltaics(PVs)and electric vehicles(EVs)may further ag gravate voltage violations and unbalance of low-voltage distribu tion networks(LVDNs).DC distribution networks can increase the accommodation of PVs and EVs and mitigate mutilple pow er quality problems by the flexible power regulation capability of voltage source *** paper proposes schemes to es tablish hybrid AC/DC LVDNs considering the conversion of the existing three-phase four-wire low-voltage AC systems to DC op *** characteristics and DC conversion constraints of typical LVDNs are *** addition,converter configura tions for typical LVDNs are proposed based on the three-phase four-wire characteristics and quantitative analysis of various DC ***,an optimal planning method of hybrid AC/DC LVDNs is proposed,which is modeled as a bi-level programming model considering the annual investments and three-phase *** are conducted to verify the effectiveness of the proposed optimal planning *** ulation results show that the proposed optimal planning method can increase the integration of PVs while simultaneously reduc ing issues related to voltage violation and unbalance.

关键词： Optimal planning low-voltage distribution net work three-phase unbalance DC conversion

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Poor oral health was associated with higher risk of gastric cancer: Evidence from 1431677 participants

引用

World Journal of Gastrointestinal Surgery 2024年第2期16卷 585-595页

作者： Fei Liu Shi-jun Tang Zi-wei Li Xu-Rui Liu Quan Lv wei zhang Dong Peng Department of Gastrointestinal Surgery The First Affiliated Hospital of Chongqing Medical UniversityChongqing 400016China Department of Pediatric Dentistry Stomatological Hospital of Guizhou Medical UniversityGuizhou 550000Guizhou ProvinceChina

BACKGROUND In recent years,the association between oral health and the risk of gastric cancer(GC)has gradually attracted increased ***,in terms of GC incidence,the association between oral health and GC incidence remains *** is reported to increase the risk of ***,some studies have shown that periodontitis has no effect on the risk of ***,the present study aimed to assess whether there is a relationship between oral health and the risk of *** To assess whether there was a relationship between oral health and the risk of *** Five databases were searched to find eligible studies from inception to April 10,***-Ottawa Scale score was used to assess the quality of included *** quality of cohort studies and case-control studies were evaluated separately in this *** of GC were described by odds ratio(OR)and 95%confidence interval(CI).Funnel plot was used to represent the publication bias of included *** performed the data analysis by StataSE *** A total of 1431677 patients from twelve included studies were enrolled for data analysis in this *** to our analysis,we found that the poor oral health was associated with higher risk of GC(OR=1.15,95%CI:1.02-1.29;I2=59.47%,P=0.000.01),gingivitis(OR=1.19,95%CI:0.71-1.67;I2=0.00%,P>0.01),dentures(OR=1.27,95%CI:0.63-1.19;I2=68.79%,P>0.01),or tooth brushing(OR=1.25,95%CI:0.78-1.71;I2=88.87%,P>0.01)had no influence on the risk of ***,patients with periodontitis(OR=1.13,95%CI:1.04-1.23;I2=0.00%,P<0.01)had a higher risk of *** Patients with poor oral health,especially periodontitis,had a higher risk of *** should be concerned about their oral *** oral health might reduce the risk of GC.

关键词： Oral health Tooth loss Periodontitis Gastric cancer Risk factor

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Urban water system theory and its model development and application

引用

Science China Earth Sciences 2024年第3期67卷 704-724页

作者： jun XIA Yongyong zhang Dunxian SHE Shiyan zhang jun YANG Mingquan LV Xiang zhang Anqi LUO Shengjun WU Yang LIU Key Laboratory of Water Cycle and Related Land Surface Processes Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China State Key Laboratory of Water Resources&Hydropower Engineering Sciences Wuhan UniversityWuhan 430072China Aquatic Eco Health Group Key Laboratory of Urban Environment and HealthInstitute of Urban EnvironmentFujian Key Laboratory of Watershed EcologyChinese Academy of SciencesXiamen 361021China Chongqing Institute of Green and Intelligent Technology Chinese Academy of SciencesChongqing 400714China

The urban water system theory is an extension of the basin water system science on an urban scale, providing a new systematic solution for the unbalanced human-water relationship and severe water challenges, such as waterlogging, black and odorous water, and ecological degradation caused by urbanization. Most existing studies on urban water systems have focused on individual water cycle processes linked with water supply and sewage treatment plants, but mutual feedback between the water cycle and its associated material circulation and water ecology, as well as human processes, still needs further exploration. In this paper, the concept, theory, and technical methodology of the urban water system were developed based on the water cycle and basin water system science. The Urban Water System 5.0(UWS 5.0) model was developed by integrating the Time Variant Gain rainfall-runoff Model with Urban water system(TVGM_Urban) in different underlying surface conditions for analyzing the natural-social water cycle processes and their associated water environmental and ecological processes and the influence of multiscale sponge measures. Herein, five major simulation functions were realized: rainfall-runoff-nonpoint source pollutant load,water and pollutant transportations through the drainage network system, terminal regulation and purification, socioeconomic water cycle, and water system assessment and regulation. The location for the case study used in this paper was Wuhan City. The findings showed that the entire urban water system should consider the built-up area and its associated rivers and lakes as the research object and explore the integrations among the urban natural-social water cycle and river regulations inside and outside of the city as well as the effects of socioeconomic development and sponge measures on the water quantity-quality-ecology processes. The UWS 5.0 model efficiently simulated the urban rainfall-runoff process, total nitrogen(TN) and total phosphoru

关键词： Urban water system Human-water relationship Water issue Green development Theoretical basis Mathematical model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Superconducting microstrip single-photon detector with system detection efficiency over 90%at 1550 nm

引用

Photonics Research 2021年第6期9卷 958-967页

作者： GUANG-ZHAO XU wei-jun zhang LI-XING YOU JIA-MIN XIONG XING-QU SUN HAO HUANG XIN OU YI-MING PAN CHAO-LIN LV HAO LI ZHEN WANG XIAO-MING XIE State Key Laboratory of Functional Materials for Informatics Shanghai Institute of Microsystem and Information TechnologyChinese Academy of Sciences(CAS)Shanghai 200050China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China CAS Center for Excellence in Superconducting Electronics Shanghai 200050China

Generally,a superconducting nanowire single-photon detector(SNSPD)is composed of wires with a typical width of∼100 *** studies have found that superconducting strips with a micrometer-scale width can also detect single *** with the SNSPD covering the same area,the superconducting microstrip single-photon detector(SMSPD)has smaller kinetic inductance,higher working current,and lower requirements in fabrication accuracy,providing potential applications in the development of ultralarge active area ***,the study of SMSPD is still in its infancy,and the realization of its high-performance and practical use remains an open *** study demonstrates a NbN SMSPD with a nearly saturated system detection efficiency(SDE)of∼92.2%at a dark count rate of∼200 cps,a polarization sensitivity of∼1.03,and a minimum timing jitter of∼48 ps at the telecom wavelength of 1550 nm when coupled with a single-mode fiber and operated at 0.84 ***,the detector’s SDE is over 70%when operated at a 2.1 K closed-cycle cryocooler.

关键词： polarization photon system

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effects of mid-passage gap with a variable surface angle on a turbine vane endwall’s aerothermal and film cooling performances

引用

Chinese Journal of Aeronautics 2024年第6期37卷 20-37页

作者： Zhiyu LI Kaiyuan zhang Zhigang LI jun LI Institute of Turbomachinery Xi’an Jiaotong UniversityXi’an 710049China

The mid-passage gap is an inevitable structure in a vane passage due to turbine vanes being manufactured *** coolant from this gap is able to prevent hot mainstream ingression and provide cooling protection for the endwall.A novel idea of enlarging the endwall’s coverage area and reducing the endwall’s thermal load by applying the mid-passage gap with variable surface angles is carried out in this *** endwall’s aerothermal and film cooling performances under four mid-passage gap modes at three typical mass flow ratio conditions are numerically *** indicate that under the traditional mid-passage mode,the coolant flows into the mainstream with a perpendicular incidence angle and can’t stick to the ***,cooling failure occurs,and the endwall’s thermal load is badly *** film cooling level at the suction-side endwall is improved when applying the mid-passage gap of a 45surface angle due to the secondary vortex being *** addition,when applying the mid-passage gap of a 135surface angle,the horseshoe vortex is pushed away,and the coverage area at the pressure-side endwall is enlarged *** best film cooling performance is achieved when the upstream surface angle is 135and the downstream surface angle is 45due to the adiabatic film cooling effectiveness being increased at both the pressure-and suction-side *** the mass flow ratio is 1.5%,the coverage area is enlarged by 43%,and the area-averaged adiabatic film cooling effectiveness is increased by 37%,when compared with those under the traditional mid-passage mode.

关键词： Film cooling Heat transfer Surface angle Mid-passagegap Turbinevane endwall

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Relationship between postoperative rehabilitation style, gastrointestinal function, and inflammatory factor levels in children with intussusception

引用

World Journal of Gastrointestinal Surgery 2024年第8期16卷 2640-2648页

作者： Xue-Yan wei Hong-Chang Huo Xin Li Su-Li Sun jun zhang Department of Outpatient Shijiazhuang Maternal and Child Health HospitalShijiazhuang 050090Hebei ProvinceChina Department of Pediatric Surgery Shijiazhuang Maternal and Child Health HospitalShijiazhuang 050090Hebei ProvinceChina Department of Nursing Shijiazhuang Maternal and Child Health HospitalShijiazhuang 050090Hebei ProvinceChina

BACKGROUND Intussusception occurs in children and progresses *** not treated in time,it may lead to secondary complications such as intestinal perforation,which affect the quality of life and health of *** is the most common clinical treatment and has a good ***,the postoperative prognosis of children with intussusception has a correlation with the postoperative rehabilitation ***,in this study,we explored the relationship between postopera-tive rehabilitation,gastrointestinal function,and the expression of inflammatory factors in children with *** medical records of 18 children who were admitted to our hospital for intussusception surgery between October 2022 and May 2024 were retrospectively *** patients were divided into the routine nursing group(n=6)and rehabilitation training group(n=12)according to the postoperative rehabilitation *** general data,gastrointestinal function,and inflammatory factor levels of the two groups were statistically *** correlation analysis of gastrointestinal function,inflammatory factors,and postoperative rehabil-itation was *** We found no significant intergroup differences in sex,age,or disease course(P>0.05).The times to first defecation,bowel sound recovery,and anal exhaust were shorter and inflammatory factor levels were lower in the rehabilitation training group than in the routine nursing group(P<0.05).Pearson correlation analysis showed that gastrin and motilin levels were positively correlated with postoperative rehabilitation(P<0.05).Interleukin(IL)-2,IL-4,IL-6,IL-10,high-sensitivity C-reactive protein,and tumor necrosis factor-αlevels were negatively correlated with postoperative rehabilitation(P<0.05).Gastrointestinal function was positively correlated(P<0.05),and levels of inflammatory factors were negatively correlated with postoperative recovery time(P<0.05).CONCLUSION We found a positive correlation between gastrointe

关键词： Children with intussusception Postoperative rehabilitation mode Gastrointestinal function Inflammatory factors

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

An artificial intelligence approach for particle transport velocity prediction in horizontal flows

引用

Particuology 2024年第9期92卷 234-250页

作者： Haoyu Chen Zhiguo Wang Hai Huang jun zhang College of Petroleum Engineering Xi'an Shiyou UniversityXi'an710065China Shaanxi Key Laboratory of Carbon Dioxide Sequestration and Enhanced Oil Recovery Xi'an710065China College of New Energy Xi'an Shiyou UniversityXi'an710065China Engineering Research Center of Smart Energy and Carbon Neutral in Oil&Gas Field Universities of Shaanxi ProvinceChina The Erosion/Corrosion Research Center The University of TulsaOK74104United States

Particle entrainment is an inevitable phenomenon in pipeline systems,especially during the development and extraction phases of oil and gas *** predicting the critical velocity for particle transport is a key focus for implementing effective sand control *** work presents a semi-supervised learning–deep hybrid kernel extreme learning machine(SSL-DHKELM)model for predicting the critical velocity,which integrates multiple machine learning theories including the deep learning approach,which is adept at advanced feature ***,the SSL framework enhances the model's capabilities when data availability is *** improved slime mould algorithm is also employed to optimize the model's *** proposed model has high accuracy on both the sample dataset and out-of-sample *** trained with only 10%of the data,the model's error still did not increase ***,this model achieves superior predictive accuracy compared to existing mechanistic models,demonstrating its impressive performance and robustness.

关键词： Particle transport Critical velocity Deep learning Semi-supervised learning Extreme learning machine

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Memristive oscillator to memristive map,energy characteristic

引用

Science China(Technological Sciences) 2024年第5期67卷 1567-1578页

作者： GUO YiTong MA jun zhang XiaoFeng HU XiKui College of Electrical and Information Engineering Lanzhou University of TechnologyLanzhou730050China Department of Physics Lanzhou University of TechnologyLanzhou730050China School of Science Chongqing University of Posts and TelecommunicationsChongqing400065China

Most of nonlinear oscillators composed of capacitive and inductive variables can obtain the Hamilton energy by using the Helmholtz theorem when the models are rewritten in equivalent vector *** energy functions for biophysical neurons can be obtained by applying scale transformation on the physical field energy in their equivalent neural *** dynamical systems often have exact energy functions,while some mathematical models just suggest generic Lyapunov functions,and the energy function is effective to predict mode *** this paper,a memristive oscillator is approached by two kinds of memristor-based nonlinear circuits,and the energy functions are defined to predict the dependence of oscillatory modes on energy *** absence of capacitive variable for capacitor,the physical time t and charge q are converted into dimensionless variables by using combination of resistance and inductance(L,R),e.g.,τ=t×R/*** energy function for each memristive map is proposed by applying the similar weights as energy function for the memristive *** example,energy function for the map is obtained by replacing the variables and parameters of the memristive oscillator with corresponding variables and parameters for the memristive *** memristive map prefers to keep lower average energy than the memristive oscillator,and chaos is generated in a discrete system with two *** scheme is helpful for energy definition in maps,and it provides possible guidance for verifying the reliability of maps by considering the energy characteristic.

关键词： Hamilton energy memristor Helmholtz theorem scale transformation memristive circuit

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：