检索结果-南通市图书馆

Experimental investigation of hypersonic flight-duplicated shock tunnel characteristics

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2021年第3期37卷 422-433,I0002页

作者： c K.Yuan z.L.jiang Institute of Mechanics Chinese Academy of SciencesBeijing 100190China University of chinese Academy of Sciences Beijing 100190China

Hypersonic air-breathing propulsion is one of the key techniques for future aviation and the ground aerodynamic testing for full scale test models with sufficient test time at flight conditions is of fundamental importance for verifying hypersonic air-breathing *** on the backward detonation-driven concept,the hypersonic flight-duplicated shock tunnel(or JF-12 shock tunnel)has been successfully constructed and *** facility is capable of reproducing airflow for Mach numbers ranging from 5 to 9 at an altitude of 25-50 km,with a test duration of more than 100 *** quantify the performance of the shock tunnel,experiments were conducted to investigate the aerodynamic characteristics of the test flows and the effects of several critical techniques that play important roles in the operation of the shock *** stagnation pressure was constant within士5%and the average stagnation pressure varied by less than 0.048%/*** variation of the stagnation pressure in repeated experiments is less than 2.0%,indicating the good repeatability of the wind *** non-uniformity of the Mach number in the core flow field at the nozzle exit was within士2.5%.Additional,a uniform flow field is established upstream of the nozzle *** axial gradients of the flow field are small since the Mach number varies less than 1.7%/*** regarding the ignition technology,diaphragm ruptures,detonation driver capacity,incident shock-wave decay,and tunnel operation mode are also *** findings of this study are not only helpful for operating the shock tunnel,but can also assist the future development of hypersonic wind tunnels.

关键词： Hypersonics Shock tunnels Flow characteristics

Numerical investigation on the flowfield of “swallowtail” cavity for supersonic mixing enhancement

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

Acta Mechanica Sinica 2009年第1期25卷 37-44页

作者： c. Wang z. jiang z. Hu J. Lu Institute or Mechanics. chinese Academy of Sciences 100190 Beijing China RecAPT Gyeongsang National University JinjuKyeongnam 660-701 South Korea

A ＂swallowtail＂ cavity for the supersonic combustor was proposed to serve as an efficient flame holder for scramjets by enhancing the mass exchange between the cavity and the main flow. A numerical study on the ＂swallow- tail＂ cavity was conducted by solving the three-dimensional Reynolds-averaged Navier-Stokes equations implemented with a k-e turbulence model in a multi-block mesh. Turbu- lence model and numerical algorithms were validated first, and then test cases were calculated to investigate into the mechanism of cavity flows. Numerical results demonstrated that the certain mass in the supersonic main flow was sucked into the cavity and moved spirally toward the combustor walls. After that, the flow went out of the cavity at its lateral end, and finally was efficiently mixed with the main flow. The comparison between the ＂swallowtail＂ cavity and the conventional one showed that the mass exchanged between the cavity and the main flow was enhanced by the lateral flow that was induced due to the pressure gradient inside the cavity and was driven by the three-dimensional vortex ring generated from the ＂swallowtail＂ cavity structure.

关键词： Supersonic mixing - Flame holder "Swallowtail" cavity - combustion ignition Numerical simulation

Donhexocin,a New Non-tetrahydrofuran Acetogenin from Goniothalamus Donnaiensis

在线全文

学校读者我要写书评

暂无评论

chinese chemical Letters 1997年第3期8卷 233-234页

作者： jiang, z Yu, DQ cHINESE AcAD MED ScI INST MAT MEDBEIJING 100050PEOPLES R CHINA BEIJING UNION MED cOLL BEIJING 100050PEOPLES R CHINA

A novel bioactive Annonaceous acetogenin, donhexocin (1), has been isolated from the roots of Goniothalamus donnaiensis (Annonaceae). 1 is a new acetogenin lacking THF rings but bearing six hydroxyls including two vic-diol systems in the aliphatic chain. Its structure and stereochemistry has been elucidated by spectoscopic analysis and derivatization.

关键词： Donhexocin,a New Non-tetrahydrofuran Acetogenin from Goniothalamus Donnaiensis

Peripheral blood RNA biomarkers can predict lesion severity in degenerative cervical myelopathy

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第6期20卷 1764-1775页

作者： zhenzhong zheng Jialin chen Jinghong Xu Bin jiang Lei Li Yawei Li Yuliang Dai Bing Wang Department of Spine Surgery The Second Xiangya Hospital of Central South UniversityChangshaHunan ProvinceChina

Degenerative cervical myelopathy is a common cause of spinal cord injury,with longer symptom duration and higher myelopathy severity indicating a worse *** numerous studies have investigated serological biomarkers for acute spinal cord injury,few studies have explored such biomarkers for diagnosing degenerative cervical *** study involved 30 patients with degenerative cervical myelopathy(51.3±7.3 years old,12 women and 18 men),seven healthy controls(25.7±1.7 years old,one woman and six men),and nine patients with cervical spondylotic radiculopathy(51.9±8.6 years old,three women and six men).Analysis of blood samples from the three groups showed clear differences in transcriptomic *** analysis identified 128 differentially expressed genes that were enriched in patients with neurological *** least absolute shrinkage and selection operator analysis,we constructed a five-gene model(TBcD,TPM2,PNKD,EIF4G2,and AP5z1)to diagnose degenerative cervical myelopathy with an accuracy of 93.5%.One-gene models(TcAP and SDHA)identified mild and severe degenerative cervical myelopathy with accuracies of 83.3%and 76.7%,*** of two immune cell types(memory B cells and memory-activated cD4^(+)T cells)predicted levels of lesions in degenerative cervical myelopathy with 80%*** results suggest that peripheral blood RNA biomarkers could be used to predict lesion severity in degenerative cervical myelopathy.

关键词： biomarkers candidate genes degenerative cervical myelopathy gene expression analysis immune cell types neurological disabilities peripheral blood RNA profiles spinal cord injury

Spectral measurements of hypervelocity flow in an expansion tunnel

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2019年第1期35卷 24-31,I0002页

作者： c.K.Yuan K.zhou Y.F.Liu z.M.Hu z.L.jiang State Key Laboratory of High-Temperature Gas Dynamic Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Sciences. University of chinese Academy of Sciences Beijing 100049China china Academy of Aerospace Aerodynamics Beijing 100074China

Atmospheric reentry vehicles and planetary probes fly through the atmosphere at hypervelocity speed. At such speed, there is a significant proportion of heat load to the vehicle surface due to radiative heating. Accurate prediction needs a good knowledge of the radiation spectrum properties. In this paper, a high-speed camera and spectrograph coupled to an intensified charge-coupled device have bee n impleme nted to inv estigate the rad i at io n flow over a semi-cylinder model. The experiments were carried out in the JF16 expansi on timnel with secondary shock velocity of 7.9 km·s^-1. Results show that the emissio n spectrum comprises several atomic lines and molecular band systems. We give detailed data of the radiation spectrum, shock shape, shock detached distance and radiation intensity varying with space and wavelength. This valuable experimental dataset will be helpful to validate computational fluid dynamics codes and radiation models, which equates to increased prediction accuracy of radiation heating. Also, some suggestions for spectral measurement in hypervelocity flow field were list in the end.

关键词： Spectral measurement Hypervelocity flow Radiation Expansion tunnel

Lipid levels and insulin resistance markers in patients with colorectal cancer:Propensity score matching analysis

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

World Journal of Gastrointestinal Oncology 2025年第1期17卷 130-142页

作者： Ren-Hao Hu Dong-Yi Yan Ke-Hui zhang Di zhang Xi-Mao cui Xiao-Hua jiang Shun zhang Department of Gastrointestinal Surgery Shanghai East HospitalSchool of MedicineTongji UniversityShanghai 200120China School of Medicine Tongji UniversityShanghai 200092China Department of Emergency Medicine Shanghai East HospitalSchool of MedicineTongji UniversityShanghai 200120China

BAcKGROUND colorectal cancer(cRc)is a prevalent malignant neoplasm characterized by subtle early *** To investigate the correlation among serum lipid profiles,the triglyceride-glucose(TyG)index,and the atherosclerotic index(AI)in patients with ***,it explored the clinical diagnostic utility of combining serum lipids with cancer antigens in the context of *** A retrospective analysis encompassed 277 patients with cRc and 1034 healthy *** Following propensity score matching,patients with cRc exhibited significantly reduced levels of serum triglyceride(TG),total cholesterol(Tc),high-density lipoprotein cholesterol,and low-density lipoprotein cholesterol(LDL-c),as well as a diminished TyG ***,they displayed elevated AI levels compared to their healthy *** in advanced stages exhibited lower serum levels of TG,Tc,and LDL-c compared to those in early *** with positive lymph node metastasis demonstrated reduced levels of TG,LDL-c,and the TyG *** operating characteristic analysis revealed that the combination of the TyG index,carcinoembryonic antigen,and carbohydrate antigen 19-9 yielded the highest positive prediction rate for cRc at 75.3%.cONcLUSION Preoperative serum lipid profiles exhibit a robust association with patients with *** concurrent assessment of multiple serum lipids and cancer antigens effectively enhances the diagnostic accuracy for cRc.

关键词： colorectal cancer Serum lipids Triglyceride-glucose index Atherosclerotic index Diagnostic marker

Silicon prepared by electro-reduction in molten salts as new energy materials

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

Journal of Energy chemistry 2020年第8期29卷 46-61,I0002页

作者： Tingting jiang Xinyi Xu George z.chen The State Key Laboratory of Refractories and Metallurgy College of Materials and MetallurgyWuhan University of Science and TechnologyWuhan 430081HubeiChina Electrochemical Technologies Group Faculty of EngineeringUniversity of NottinghamNottingham NG27RDUK Electrochemical Technologies Group Faculty of Science and EngineeringUniversity of Nottingham Ningbo ChinaNingbo 315100ZhejiangChina

Silicon has a large impact on the energy supply and economy in the modern world. In industry, high purity silicon is firstly prepared by carbothermic reduction of silica with the produced raw silicon being further refined by a modified Siemens method. This process suffers from the disadvantages of high cost and contaminant release and emission. As an alternative, the molten salt electrolysis approach, particularly the FFc cambridge Process(FFc: Fray-Farthing-chen), could realize high purity silicon products with morphology-controllable nanostructures at low or mild temperatures(generally 650–900 ℃). In this article, we review the development, reaction mechanisms, and electrolysis conditions of silicon production by the FFc cambridge Process. Applications of the silicon products from electrolysis in molten salts are also discussed in terms of energy applications, including using them as the photovoltaic element in solar cells and as the charge storage phase in the negative electrode(negatrode) of lithium ion batteries.

关键词： Electrolysis Molten salt Silicon Nanomaterial Li ion battery Solar cell

FAcTORS ON VIScOSITY STABILITY OF MOLD FLUXES

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2004年第2期17卷 175-180页

作者： c.Y.zhu c.J.Liu M.F.jiang z.D.Yang NortheasternUniversity Shenyang110004China Ji＇nanIronandSteelGroupco. Ji＇nan250101China

Viscosity stability indexes of mold flux at high temperature and low temperature havebeen introduced and the effects of flux compositions on viscosity stability indexeshave been studied. Two mold fluxes have been developed by analyzing the effects offlux viscosity stability on the process and the condition of continuous casting slab ofmedium carbon steel. The results show that the fluxes are suitable for the process.

关键词： mold flux viscosity stability index high temperature low temperature

Impacts of the annual cycle of background SST in the tropical Pacific on the phase and amplitude of ENSO

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2025年第01期 14-19页

作者： Song jiang congwen zhu Ning jiang State Key Laboratory of Severe Weather (LASW) Chinese Academy of Meteorological Sciences college of Earth and Planetary Sciences University of Chinese Academy of Sciences

基于1982–2022年资料分析,本文发现,热带太平洋海温年循环的主导模态为反对称模式,是ENSO发展的背景场.然而,其对ENSO相位和振幅的异常影响尚未可知.反对称模态异常可以通过Bjerknes反馈影响ENSO的年际变化,其正(负)异常可以通过更早(... 详细信息

基于1982–2022年资料分析,本文发现,热带太平洋海温年循环的主导模态为反对称模式,是ENSO发展的背景场.然而,其对ENSO相位和振幅的异常影响尚未可知.反对称模态异常可以通过Bjerknes反馈影响ENSO的年际变化,其正(负)异常可以通过更早(更晚)的季节循环转变时间和更大(更小)的年平均值增强冬季El Ni?o (La Ni?a)的强度.根据随机敏感性实验分析,与反对称模态变化有关的赤道中东太平洋海温异常可达±0.3℃以上.研究结果为背景海温年循环对ENSO的影响提供了新的见解,这可能对ENSO的预测具有重要意义.

关键词：年循环海表面温度异常反对称模态 ENSO