检索结果-南通市图书馆

Influence of ground effect on flow field structure and aerodynamic noise of high-speed trains

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第2期25卷 147-160页

作者： Xiaoming TAN Linli GONG xiaohong zhang Zhigang YANG Key Laboratory of Intelligent Manufacturing and Service Performance Optimization of Laser and Grinding in Mechanical Industry Hunan Institute of Science and TechnologyYueyang414000China Key Laboratory of Traffic Safety on Track(Central South University) Ministry of EducationSchool of Traffic&Transportation EngineeringCentral South UniversityChangsha410075China

The simulation of the ground effect has always been a technical difficulty in wind tunnel tests of high-speed trains.In this paper,large eddy simulation and the curl acoustic integral equation were used to simulate the flow-acoustic field results of high-speed trains under four ground simulation systems(GSSs):“moving ground+rotating wheel”,“stationary ground+rotating wheel”,“moving ground+stationary wheel”,and“stationary ground+stationary wheel”.By comparing the fluid-acoustic field results of the four GSSs,the influence laws of different GSSs on the flow field structure,aero-acoustic source,and far-field radiation noise characteristics were investigated,providing guidance for the acoustic wind tunnel testing of high-speed trains.The calculation results of the aerodynamic noise of a 350 km/h high-speed train show that the moving ground and rotating wheel affect mainly the aero-acoustic performance under the train bottom.The influence of the rotating wheel on the equivalent sound source power of the whole vehicle was not more than 5%,but that of the moving ground slip was more than 15%.The average influence of the rotating wheel on the sound pressure level radiated by the whole vehicle was 0.3 dBA,while that of the moving ground was 1.8 dBA.

关键词： High-speed train Aero-acoustics Flow field structure Large eddy simulation Moving ground condition Rotating wheel

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 improved GNSS ambiguity best integer equivariant estimation method with Laplacian distribution for urban low-cost RTK positioning

引用

Satellite Navigation 2024年第1期5卷 109-124页

作者： Ying Liu Wanke Liu xiaohong zhang Yantao Liang Xianlu Tao Liye Ma School of Geodesy and Geomatics Hubei Luojia LaboratoryWuhan University129 Luoyu RoadWuhan430079HubeiChina Chinese Antarctic Center of Surveying and Mapping Wuhan University129 Luoyu RoadWuhan430079HubeiChina School of Instrument Science and Engineering Southeast UniversityNanjingJiangsuChina The 54 Research Institute of China Electronics Technology Group CorporationShijiazhuang050081HebeiChina State Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang050081HebeiChina

The integer least squares(ILS)estimation is commonly used for carrier phase ambiguity resolution(AR).More recently,the best integer equivariant(BIE)estimation has also attracted an attention for complex application scenarios,which exhibits higher reliability by a weighted fusion of integer candidates.However,traditional BIE estimation with Gaussian distribution(GBIE)faces challenges in fully utilizing the advantages of BIE for urban low-cost positioning,mainly due to the presence of outliers and unmodeled errors.To this end,an improved BIE estimation method with Laplacian distribution(LBIE)is proposed,and several key issues are discussed,including the weight function of LBIE,determination of the candidates included based on the OIA test,and derivation of the variance of LBIE solutions for reliability evaluation.The results show that the proposed LBIE method has the positioning accuracy similar to the BIE using multivariate t-distribution(TBIE),and significantly outperforms the ILS-PAR and GBIE methods.In an urban expressway test with a Huawei Mate40 smartphone,the LBIE method has positioning errors of less than 0.5 m in three directions and obtains over 50%improvements compared to the ILS-PAR and GBIE methods.In an urban canyon test with a low-cost receiver STA8100 produced by STMicroelectronics,the positioning accuracy of LBIE in three directions is 0.112 m,0.107 m,and 0.252 m,respectively,with improvements of 17.6%,27.2%,and 26.1%compared to GBIE,and 23.3%,28.2%,and 30.6%compared to ILS-PAR.Moreover,its computational time increases by 30–40%compared to ILS-PAR and is approximately half of that using TBIE.

关键词： Ambiguity resolution Best integer equivariant estimation Laplacian distribution Urban environments Low-cost GNSS receivers Real-time kinematic

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

Broad-spectrum ginsentides are principal bioactives in unraveling the cure-all effects of ginseng

引用

Acta Pharmaceutica Sinica B 2024年第2期14卷 653-666页

作者： Shining Loo Antony Kam Bamaprasad Dutta xiaohong zhang Nan Feng Siu Kwan Sze Chuan-Fa Liu Xiaoliang Wang James P.Tam School of Biological Sciences Nanyang Technological UniversitySingapore 637551Singapore Academy of Pharmacy Xi’an Jiaotong-Liverpool UniversitySuzhou 215123China Department of Biological Sciences Xi’an Jiaotong-Liverpool UniversitySuzhou 215123China Institute of Materia Medica Chinese Academy of Medical SciencesBeijing 100050China Department of Health Sciences Brock UniversityNiagara RegionON L2S 3A1Canada

Stress and illness connection is complex and involves multiple physiological systems.Panax ginsengs,reputed for their broad-spectrum“cure-all”effect,are widely prescribed to treat stress and related illnesses.However,the identity of ginseng’s“cure-all”medicinal compounds that relieve stress remains unresolved.Here,we identify ginsentides as the principal bioactives that coordinate multiple systems to restore homeostasis in response to stress.Ginsentides are disulfide-rich,cell-penetrating and proteolytic-stable microproteins.Using affinity-enrichment mass spectrometry target identification together with in vitro,ex vivo and in vivo validations,we show that highly purified or synthetic ginsentides promote vasorelaxation by producing nitric oxide through endothelial cells via intracellular PI3K/Akt signaling pathway,alleviate a1-adrenergic receptor overactivity by reversing phenylephrine-induced constriction of aorta,decrease monocyte adhesion to endothelial cells via CD166/ESAM/CD40 and inhibit P2Y12 receptors to reduce platelet aggregation.Orally administered ginsentides were effective in animal models to reduce ADP-induced platelet aggregation,to prevent collagen and adrenalineinduced pulmonary thrombosis as well as anti-stress behavior of tail suspension and forced swimming tests in mice.Together,these results strongly suggest that ginsentides are the principal panacea compounds of ginsengs because of their ability to target multiple extra-and intra-cellular proteins to reverse stress-induced damages.

关键词： Ginseng Cysteine-rich peptides Microproteins Cure-all Stress Homeostasis

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

Externallyvalidated nomogramfor predicting short-term pregnancy outcome of singleton pregnancies with fetal growth restriction(FGR)

引用

Gynecology and Obstetrics Clinical Medicine 2024年第1期4卷 21-30页

作者： Fufen Yin Mingrui Jin Yujing Li Yang Li Xiuju Yin Junshu Xie xiaohong zhang Department of Obstetrics and Gynecology Peking University People's HospitalBeijingChina Department of Ophthalmology Beijing Tongren Eye CenterCapital Medical UniversityBeijingChina Department of Pathology China Medical University College of Basic Medical SciencesShenyangLiaoningChina Department of Obstetrics and Gynecology The Affiliated Hospital of Qingdao UniversityQingdaoShandongChina

Objective This studyaimed at developing an available predictive model of singleton pregnancies with fetal growth restriction(FGR)for accurate and individualised prognosis assessment.Methods The prediction nomogram was developed by using multivariable Cox regression with data for 301 singleton FGR pregnancies at Peking University People's Hospital.External validation was performed in 321eligible singleton FGR pregnancies at the Affiliated Hospital of Qingdao University.Results Absent umbilical arterial flow,fetal anomaly,history of abnormal pregnancy,non-cephalic presentation and historyof caesarean sectionwere independent prognostic factors foradverse perinatal outcomes in singleton FGR pregnancies in the training set.In the training cohort of the internal validation set,the nomogram estimated pregnancy prognosis of FGR singleton pregnancies based on these five variables,with a concordance index(C-index)of 0.859(95%Cl:0.81 to 0.90)for predicting termination of pregnancy(TOP),which included intrauterine fetal death and therapeutic lethal induction,with a C-index of 0.92(95%Cl:0.86 to 0.98)for predicting stillbirth,and a C-index of 0.87(95%Cl:0.83 to 0.92)for predicting therapeutic lethal induction with indications.Encouragingly,consistent results wereobserved in the external validation set,witha C-index of 0.776(95%Cl:0.71 to 0.84)for predicting TOP,which included intrauterine fetal death and therapeutic lethal induction,with a C-index of 0.773(95%Cl:0.70 to 0.84)for predicting stillbirth,and a C-index of 0.776(95%Cl:0.70 to 0.85)for predicting therapeutic lethal induction with indications.Furthermore,the calibrations of the nomograms predicting the 28th and 34th TOPfreegestation week strongly corresponded to theactual survivaloutcome.Conclusion This prediction model may help clinicians indecision-making for singleton pregnancies with FGR,especially for patients with a single abnormal umbilical arterial flow orfetal anomaly,without induced labour indications for these abnormalities.

关键词： fetal pregnancy nomogram

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

Wind speed retrieval using GNSS-R technique with geographic partitioning

引用

Satellite Navigation 2023年第1期4卷 140-154,I0005页

作者： Zheng Li Fei Guo Fade Chen Zhiyu zhang xiaohong zhang School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China

In this paper,the efect of geographical location on Cyclone Global Navigation Satellite System(CYGNSS)observables is demonstrated for the frst time.It is found that the observables corresponding to the same wind speed vary with geographic location regularly.Although latitude and longitude information is included in the conventional method,it cannot efectively reduce the errors caused by geographic diferences due to the non-monotonic changes of observables with respect to latitude and longitude.Thus,an improved method for Global Navigation Satellite System Refectometry(GNSS-R)wind speed retrieval that takes geographical diferences into account is proposed.The sea surface is divided into diferent areas for independent wind speed retrieval,and the training set is resampled by considering high wind speed.To balance between the retrieval accuracies of high and low wind speeds,the results with the random training samples and the resampling samples are fused.Compared with the conventional method,in the range of 0–20 m/s,the improved method reduces the Root Mean Square Error(RMSE)of retrieved wind speeds from 1.52 to 1.34 m/s,and enhances the correlation coefcient from 0.86 to 0.90;while in the range of 20–30 m/s,the RMSE decreases from 8.07 to 4.06 m/s,and the correlation coefcient increases from 0.04 to 0.45.Interestingly,the SNR observations are moderately correlated with marine gravities,showing correlation coefcients of 0.5–0.6,which may provide a useful reference for marine gravity retrieval using GNSS-R in the future.

关键词： CYGNSS Geographical diferences Ocean wind speed GNSS refectometry Marine gravity

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

Instantaneous velocity determination and positioning using Doppler shift from a LEO constellation

引用

Satellite Navigation 2023年第1期4卷 28-40,I0002页

作者： Fei Guo Yan Yang Fujian Ma Yifan Zhu Hang Liu xiaohong zhang School of Geodesy and Geomatics Wuhan UniversityWuhan 430079China Hubei Luojia Laboratory Wuhan 430079China Institute of Telecommunication and Navigation Satellites China Academy of Space TechnologyBeijingChina

To provide backup and supplementation for the Global Navigation Satellite System(GNSS),Doppler shift from Low Earth Orbit(LEO)satellites can be used as signals of opportunity to provide positioning,navigation,and timing service.In this contribution,we frst investigate the model and performance of instantaneous velocity determination and positioning with LEO satellites.Given a LEO constellation with 288 satellites,we simulate Doppler shift observations at nine multi-GNSS experiment stations.Owing to the lower orbit,the performance of LEO velocity determination is much more sensitive to the initial receiver position error than that of GNSS.Statistical results show that with the initial receiver position error increased from 0.1 to 10 m,the Root Mean Square Errors(RMSEs)increase from 0.73 to 2.65 cm/s,0.68 to 2.96 cm/s,and 1.67 to 4.15 cm/s in the east,north,and up directions,respectively.The performances with GPS are compared with GPS+LEO,and it is found that LEO Doppler shift observations contribute to GPS velocity determination.As for LEO Doppler positioning,even if more than 30 visible LEO satellites are available,the position dilution of precision values can reach several hundreds.Assuming that the error of LEO Doppler measurements is 0.01 m/s,the instantaneous Doppler positioning accuracy can achieve about a few meters,which is comparable to that of GNSS pseudorange positioning.A constant velocity model is adopted for state transition.Static LEO Doppler positioning results show that an accuracy at centimeter to decimeter level can be achieved after solution convergence.For a static simulated kinematic positioning test,the RMSEs range from a few decimeters to several meters in diferent regions by giving diferent constraints.For a dynamic positioning test,the RMSEs are about 2–3 m in high latitude region.

关键词： Low earth orbit(LEO) GNSS Doppler shift Velocity determination Instantaneous Doppler positioning

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

Advancement in research on genes associated with fetal congenital heart disease(CHD)and diagnostic testing methods

引用

Gynecology and Obstetrics Clinical Medicine 2023年第2期3卷 94-99页

作者： Junshu Xie Kexin zhang xiaohong zhang Obstetrics and Gynecology Peking University People's HospitalBeijing100044China

Introduction:Congenital heart disease(CHD)is one of the most common congenital malformations,and is a polygenic disease related to some major genes and involved in environmental factors.With the progress of science and technology,the progress was both in the studies of genetic patterns and testing methods.Understanding how each gene participates in normal and pathological anatomy is an important goal of CHD research.We reviewed the development of testing methods and CHD-related genes,to provide some enlightenment for the CHD prenatal diagnosis and hope to realize the intervention and treatment on the gene level of CHD in the future.

关键词： Congenital heart disease Single cell RNA Sequencing Genetic factors Gene network

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

TDS-1 GNSS reflectometry wind geophysical model function response to GPS block types

引用

Geo-Spatial Information Science 2022年第2期25卷 312-324页

作者： Fade Chen xiaohong zhang Fei Guo Jiazhu Zheng Yang Nan Mohamed Freeshah School of Geodesy and Geomatics Wuhan UniversityWuhanChina College of Civil Engineering Nanjing Forestry UniversityNanjingChina GNSS Research Center Wuhan UniversityWuhanChina State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina Surveying Engineering Department Shoubra Faculty of EngineeringBenha UniversityBenhaEgypt

This paper presents the TDS-1 GNSS reflectometry wind Geophysical Model Function(GMF)response to GPS block types.The observables were extracted from Delay Doppler Maps(DDMs)after taking the receiver antenna gains effects and GNSS-R geometry effects into account.Since the DDM is affected by GPS EffectiveIsotropic Radiated Power(EIRP),we first investigate the sensitivity of observables to the GPS block.Additionally,the observables at high SNRs are more sensitive to wind speed,but the spatial coverage at high signal to noise ratios(SNRs)is lower,while DDMs at low SNRs have the opposite characteristics.To balance the accuracy and spatial coverage,the DDM datasets are divided into two parts:high SNR(>0 dB)and low SNR(>−10 dB and≤0 dB)to develop wind GMF.Then,the influences of GPS block on wind speed retrieval both at high and low SNR is analyzed.Results show that the block types have impacts on wind GMF and the use of a prior GPS block can contribute to a better wind speed retrieval both at high and low SNR.Compared with ASCAT,the Root Mean Square Error(RMSE)value of wind speed retrieval at high and low SNR are 2.19 m/s and 3.13 m/s,respectively,when all TDS data are processed without distinguishing GPS block types.However,if the TDS data are separately processed and used to develop wind GMF through different blocks,both the accuracy and correlation coefficient can be improved to some extent.Finally,the influence of significant height of the swell(Hs)on SNR observables is analyzed,and it is demonstrated that there is no obvious linear or nonlinear relationship between them.

关键词： Global Navigation Satellite System-Reflectometry(GNSS-R) Delay-Doppler Map(DDM) wind speed Geophysical Model Function(GMF) TechDemoSat-1(TDS-1) GPS block

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

Gga3 gene-deleted C57BL/6J mice have elevated fasting blood glucose levels

引用

Genes & Diseases 2023年第6期10卷 2206-2209页

作者： xiaohong zhang Song Yue Dongjun Jiang Guoan zhang Jianli Liu Xuezhi Li Shandong Collaborative Innovation Center for Diagnosis Treatment and Behavioral Interventions of Mental DisordersInstitute of Mental HealthJining Medical UniversityJiningShandong 272013China Shandong Key Laboratory of Behavioral Medicine School of Mental HealthJining Medical UniversityJiningShandong 272013China Department of Pathology Weifang Medical UniversityWeifangShandong 261053China Institute of Forensic Medicine and Laboratory Medicine Jining Medical UniversityForensic Science Center of Jining Medical UniversityJiningShandong 272067China Department of Pathology Affiliated Hospital of Jining Medical UniversityJiningShandong 272000China

Diabetes mellitus(DM)is one of the most common diseases in the elderly,and among DM patients,more than 90%have type 2 DM(T2DM).The etiology of T2DM is complex and associated with risk factors such as age,genetic disposition,and diet.The genetic factors underlying T2DM are currently the focus of intense research,and it has been established that the susceptibility genes associated with T2DM vary among different populations.A recent longitudinal exome-wide association study in the Japanese population has identified GGA3 as a susceptible locus for T2DM.1 GGA3 is one of the Golgi-localized-ear-containing ARF binding proteins(GGAs)that function widely in the transport of Golgi-derived vesicles and in endocytic trafficking pathways.However,although it is widely acknowledged that the control of glucose homeostasis via endocytosis and glucose metabolism plays a vital role in T2DM,the associations between intracellular trafficking and diabetes pathogenesis have not been sufficiently established.In this study,we used a Gga3 gene knockout mouse strain to investigate the potential involvement of GGA3 in controlling blood glucose.The study was approved by the ethics committee of Jining Medical University(No.2019-JS-005).Our results indicate that the GGA3 gene might play a protective role against diabetes.

关键词： metabolism elevated protective

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

Advanced Materials and Technologies toward Carbon Neutrality

引用

Accounts of Materials Research 2022年第9期3卷 913-921页

作者： Chao Lu xiaohong zhang Xi Chen College of Chemistry Chemical Engineering and Materials ScienceSoochow UniversitySuzhouJiangsu 215123China Institute of Functional Nano&Soft Materials Soochow UniversitySuzhouJiangsu 215123China Department of Earth and Environmental Engineering Columbia UniversityNew YorkNew York 10027United States

CONSPECTUS:Global climate change caused by the excessive emission of greenhouse gases has become one of the greatest threats to human survival in the 21st century.Carbon dioxide is the main greenhouse gas on earth and has brought about serious environmental problems nowadays.On the basis of the current situation,it is urgent to reach the peak of carbon dioxide emission and then achieve carbon neutrality via policy support and engineering strategies within advanced materials and technologies.Carbon neutrality requires an appropriate balance between the emission and reduction of carbon dioxide.The emission of carbon dioxide mainly comes from modern industries,and the reduction requires several steps,including capture,conversion,and application.On one hand,it can reduce carbon dioxide emission by promoting the transformation of industrial structure.

关键词： structure. dioxide neutral

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

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：