检索结果-南通市图书馆

Applied Mathematics and Mechanics(English Edition) 2016年第11期37卷 1571-1586页

作者： Zhijun SHEN xiao LI Jian ren Institute of Applied Physics and Computational Mathematics Beijing 100088China Center for Applied Physics and Technology Peking UniversityBeijing 100071China Graduate School Chinese Academy of Engineering PhysicsBeijing 100088China

The study of cylindrically symmetric compressible fluid is interesting from both theoretical and numerical points of view. In this paper, the typical spherical sym- metry properties of the numerical schemes are discussed, and an area weighted scheme is extended from a Lagrangian method to an arbitrary Lagrangian and Eulerian （ALE） method. Numerical results are presented to compare three discrete configurations, i.e., the control volume scheme, the area weighted scheme, and the plane scheme with the addition of a geometrical source. The fact that the singularity arises from the geometri- cal source term in the plane scheme is illustrated. A suggestion for choosing the discrete formulation is given when the strong shock wave problems are simulated.

关键词： arbitrary Lagrangian and Eulerian (ALE) cylindrical geometry symmetrypreservation unstructured grid

Heel pain caused by os subcalcis:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2022年第16期10卷 5373-5379页

作者： Saijilafu Suo-Yuan Li xiao Yu Zhi-Qiang Li guang Yang Jing-Huan Lv guang-Xiang Chen ren-Jie Xu Department of Orthopaedics Soochow UniversitySuzhou 215007Jiangsu ProvinceChina Department of Orthopaedics the Affiliated Suzhou Hospital of Nanjing Medical UniversitySuzhou Municipal HospitalSuzhou 215000Jiangsu ProvinceChina Department of pathology the Affiliated Suzhou Hospital of Nanjing Medical UniversitySuzhou Municipal HospitalSuzhou 215000Jiangsu ProvinceChina

BACKGROUND The accessory bones are common bone variations around the feet and ankles,which usually originate from nonunion of the secondary ossification center adjacent to the main bone mass,and most of them remain *** subcalcis is an accessory bone at the plantar aspect of the calcaneus,which is located just posterior to the insertion of the plantar *** bone formation at the calcaneal plantar pole with heel pain has rarely been *** SUMMARY A 55-year-old man presented to our clinic with left plantar heel pain and a progressive swelling for 8 years.X-ray,computer tomography and magnetic resonance imaging showed a large os subcalcison the plantar side of the calcaneus,located at the insertion of the plantar *** underwent surgical excision of the *** the bony trabeculae were intermingled with fat and covered with *** This is a rare case with accessory os subcalcis leading to heel *** highlights the awareness of os subcalcis and helps avoid future misdiagnosis of heel pain.

关键词： Heel pain Accessory ossicle Calcaneus Os subcalcis Case report

Influence of Vanes and Blades on Ingress in Axial Rim Seal for Turbine Stages

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 Thermal Science 2024年第3期33卷 833-846页

作者： ren Ran DU Qiang LIU guang ZENG Yanlian XIE Lei Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing100190China National Key Laboratory of Science and Technology on Advanced Light-duty Gas-turbine Beijing100190China School of Aeronautics and Astronautics University of Chinese Academy of SciencesBeijing100190China

Hot gas ingestion refers to the phenomenon of mainstream hot gas flowing into the space cavity of a turbine *** studies have found that mainstream annulus pressure distribution plays an important role in hot gas ingestion,but due to its complexity,the mechanism of the interaction between mainstream flow and hot gas ingestion remains *** paper adopts the URANS method,and three sealing flow rates are considered,named C_(w)=0,C_(w)=500,and C_(w)=*** time-averaged annulus pressure distribution shows that an increase in the sealing flow decreases the pressure value,and the effects of the sealing flow on the pressure distribution of the leading edge of the blade are much more influential than that of the trailing edge of the *** unsteady pressure time-space distribution in the annulus indicates that a time-space tilted distribution of pressure at the rim exits when the sealing flow *** phenomenon is mainly due to the strong feedback mechanism of the sealing flow to the annulus pressure field.A comparison of the pressure and mean radial velocity distribution of the mainstream shows that the ingestion mainly occurs on the blade side,where the pressure is lower than on the vane *** flow characteristics at the wheel rim are analyzed with a sealing flow rate C_(w)=5000,and under these conditions,both pressure-induced ingestion and ingestion caused by a passage vortex can be *** three-dimensional and inertial effects of the mainstream at the wheel rim lead to the generation of separation vortices on the blade side,and the presence of separation vortices leads to ingestion along the blade *** the same time,pressure on the blade side will cause the fluid to have a radial inward flow tendency,which will promote the formation of separation vortices,leading to more serious ingestion in the high-pressure region on the blade *** blade pressure field can be more significant than the vane trailing pressure field in the rim sea

关键词： separation vortex unsteady rim seal the effect of blade on ingestion

Factors predicting the instant effect of motor function after subthalamic nucleus deep brain stimulation in Parkinson’s disease

在线全文

学校读者我要写书评

暂无评论

Translational Neurodegeneration 2017年第1期6卷 139-146页

作者： Xin-Ling Su xiao-guang Luo Hong Lv Jun Wang Yan ren Zhi-Yi He Department of Neurology First Affiliated HospitalChina Medical UniversityChina Medical University155 Nanjing North StreetHeping DistrictShenyang 110001China Department of Neurosurgery First Affiliated HospitalChina Medical UniversityChina Medical UniversityShenyangChina

Background:Subthalamic nucleus deep brain stimulation(STN-DBS)is an effective treatment for Parkinson’s disease(PD),the predictive effect of levodopa responsiveness on surgical outcomes was confirmed by some studies,however there were different conclusions about that through long-and short-term *** aimed to investigate the factors which influence the predictive value of levodopa responsiveness,and discover more predictive factors of surgical ***:Twenty-three PD patients underwent bilateral STN-DBS and completed our *** evaluations were performed 1 week before and 3 months after ***:STN-DBS significantly improved motor function of PD patients after 3 months;preoperative levodopa responsiveness and disease subtype predicted the effect of DBS on motor function;gender,disease duration and duration of motor fluctuations modified the predictive effect of levodopa responsiveness on motor improvement;the duration of motor fluctuations and severity of preoperative motor symptoms modified the predictive effect of disease subtype on motor ***:The intensity of levodopa responsiveness served as a predictor of motor improvement more accurately in female patients,patients with shorter disease duration or shorter motor fluctuations;PD patients with dominant axial symptoms benefit less from STN-DBS compared to those with limb-predominant symptoms,especially in their later disease stage.

关键词： Parkinson’s disease Deep brain stimulation Subthalamic nucleus Predictive factors Levodopa responsiveness

Infectious Behavior in Photo-oxidation of Polymers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2020年第3期38卷 248-256,I0006页

作者： Xuan Liu xiao-Peng ren Rui Yang Department of Chemical Engineering Tsinghua University

When a polymer is used together with others,its aging process will be affected by the adjacent *** infectious behavior between polymers makes the aging process more complex than that of an individual *** this study,infectious behavior in photooxidation of polymers was ***(PPs),an unstabilized PP and a commercial PP,were chosen as the infection *** typical polymers,high density polyethylene(HDPE),low density polyethylene(LDPE),polystyrene(PS),polycarbonate(PC),poly(ethylene terephthalate)(PET),and polyamide 6(PA6),were used as the *** degree of oxidation of the targets was evaluated by attenuated total reflection-Fourier transform infrared spectroscopy(ATR-FTIR).An accelerating effect of two infection sources on the photo-oxidation of the target polymers was *** infectious agents from the infection sources were detected by pyrolysis-gas chromatography-mass spectrometry(Py-GC-MS)and gas chromatography(GC).The acceleration effect of two main infectious agents,*** and acetic acid,on the photo-oxidation of the commercial PP was *** infectious effect of the infection source on the target polymer was considered to be a comprehensive result of the effects of a variety of infectious agents.

关键词： Photo-oxidation Infection source Infectious agent Polypropylene

Arithmetic-analytical Expression of the Koch-type Curves and Their Generalizations (Ⅰ)

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2015年第4期31卷 1167-1180页

作者： xiao-ling YANG guang-jun YANG Statistics and Mathematics College Yunnan University of Finance and Economics Mathematics and Statistics College Yunnan University

In this paper, by constructing the one-to-one correspondence between its IFS and the quaternary fractional expansion, the n-th iteration analytical expression and the limit representation of the family of the Koch-type curves with arbitrary angles are obtained. The distinction between our method and that of H. Sagan is that we provide the generation process analytically and represent it as a graph of a series function which looks like the Weierstrass function. With these arithmetic expressions, we further analyze and prove some of the fractal properties of the Koch-type curves such as the self-similarity, the HSlder exponent and with the property of continuous everywhere but differentiable nowhere. Then, we will show that the Koch- type curves can be approximated by different constructed generators. Based on the analytic transformation of the Koch-type curves, we also constructed more continuous but nowhere-differentiable curves represented by arithmetic expressions. This result implies that the analytical expression of a fractal has theoretical and practical significance.

关键词： the family of Koch-type curves arithmetic-analytical expression binary expansion series analyt-ical transformation stitched curve

Effects of telbivudine and entecavir for HBeAg-positive chronic hepatitis B: A meta-analysis

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2012年第43期18卷 6290-6301页

作者： Qi-Min Su xiao-guang Ye Department of Infectious Diseases the Second Affiliated Hospital of Guangzhou Medical UniversityGuangzhou 510260Guangdong ProvinceChina

AIM:To compare the effects of telbivudine (LDT) and entecavir (ETV) in treatment of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B by meta-analysis. METHODS:We conducted a literature search using PubMed, MEDLINE, EMBASE, the China National Knowledge Infrastructure, the VIP database, the Wanfang database and the Cochrane Controlled Trial Register for all relevant articles published before April 1, 2012. Randomized controlled trials (RCTs) comparing LDT with ETV for treatment of HBeAg-positive chronic hepatitis B were included. The data was analyzed with Review Manager Software 5.0. We used relative risk (RR) as an effect measure, and reported its 95% CI. Meta-analysis was performed using either a fixedeffect or random-effect model, based on the absence or presence of significant heterogeneity. Two reviewers assessed the risk of bias and extracted data indepen- dently and in duplicate. The analysis was executed using the main outcome parameters including hepatitis B virus (HBV) DNA undetectability, alanine aminotransferase (ALT) normalization, HBeAg loss, HBeAg seroconversion, drug-resistance, and adverse reactions. Meta-analysis of the included trials and subgroup analyses were conducted to examine the association between pre-specified characteristics with the therapeutic effects of the two agents. RESULTS:Thirteen eligible trials (3925 patients in total) were included and evaluated for methodological quality and heterogeneity. In various treatment durations of 4 wk, 8 wk, 12 wk, 24 wk, 36 wk, 48 wk, 52 wk, 60 wk and 72 wk, the rates of HBV DNA undetectability and ALT normalization in the two groups were similar, without statistical significance. At 4 wk and 8 wk of the treatment, no statistical differences were found in the rate of HBeAg loss between the two groups, while the rate in the LDT group was higher than in the ETV group at 12 wk, 24 wk, 48 wk and 52 wk, respectively (RR 2.28, 95% CI 1.16, 7.03, P = 0.02; RR 1.45, 95% CI 1.16, 1.82, P = 0.001; R

关键词： Telbivudine Entecavir Hepatitis B e antigen-positive chronic hepatitis B Randomized controlled trials Meta-analysis

Innovation Analysis Approach to Design Parameters of High Speed Train Carriage and Their Intrinsic Complexity Relationships

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2017年第5期30卷 1091-1100页

作者： Shou-Ne xiao Ming-Meng Wang guang-Zhong Hu guang-Wu Yang State Key Laboratory of Traction Power Southwest Jiaotong University School of Mechanical Engineering Sichuan University of Science & Engineering

In view of the problem that it＇s difficult to accurately grasp the influence range and transmission path of the vehicle top design requirements on the underlying design parameters. Applying directed-weighted complex network to product parameter model is an important method that can clarify the relationships between product parameters and establish the top-down design of a product. The relationships of the product parameters of each node are calculated via a simple path searching algorithm, and the main design parameters are extracted by analysis and comparison. A uniform definition of the index formula for out-in degree can be provided based on the analysis of out- in-degree width and depth and control strength of train carriage body parameters. Vehicle gauge, axle load, crosswind and other parameters with higher values of the out-degree index are the most important boundary condi- tions; the most considerable performance indices are the parameters that have higher values of the out-in-degree index including torsional stiffness, maximum testing speed, service life of the vehicle, and so on; the main design parameters contain train carriage body weight, train weight per extended metre, train height and other parameters with higher values of the in-degree index. The network not only provides theoretical guidance for exploring the relationship of design parameters, but also further enriches the appli- cation of forward design method to high-speed trains.

关键词： Train carriage body parameters Complexnetwork Width influence Depth influence Parametercontrol strength

Redox-active nanoparticles for inflammatory bowel disease

在线全文

学校读者我要写书评

暂无评论

Nano Research 2021年第8期14卷 2535-2557页

作者： Qinjuan ren Si Sun xiao-Dong Zhang Department of Physics and Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology School of SciencesTianjin UniversityTianjin 300350China Tianjin Key Laboratory of Brain Science and Neural Engineering Academy of Medical Engineering and Translational MedicineTianjin UniversityTianjin 300072China

Homeostasis of gut microbiota is extremely essential for maintaining nutrient metabolism and regulating immunological *** increasing evidence suggests that inflammatory bowel disease(IBD)is strongly associated with dysregulation of gut *** activated inflammation,excessive reactive oxygen species(ROS)and reactive nitrogen species(RNS)produced by inflammatory cells play a detrimental role in regulating IBD and gut ***/RNS cause damage to the surrounding tissues,including nutrient absorption disorders,intestinal dysmotility and barrier ***,ROS/RNS provide terminal electron receptors for anaerobic respiration and support the bloom of facultative anaerobes,eventually causing gut microbiota ***-active nanoparticles(NPs)with catalytic properties or enzyme-like activities can effectively scavenge ROS/RNS,and selectively target inflamed sites via ultrasmall size-mediated enhanced permeation and retention(EPR)effect,showing great potential to regulate IBD and maintain the homeostasis of gut *** addition,the widespread application of NPs in commercial products 1 has increased their accumulation in healthy organisms,and the biological effects on normal microbiota resulting from long-term exposure of NPs to gastrointestinal tract also need attention.

关键词： gut microbiota IBD ROS/RNS redox-active NPs

Wandering Subspaces and Quasi-wandering Subspaces in the Hardy-Sobolev Spaces

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 Mathematica Sinica,English Series 2017年第12期33卷 1684-1692页

作者： Jie Sheng xiao guang Fu CAO Nanhu College Jiaxing University Department of Mathematics South China Apicultural University

In this paper, we prove that for -1/2≤β≤0, suppose M is an invariant subspaces of the Hardy Sobolev spaces Hβ^2（D） for Tz^β, then M zM is a generating wandering subspace of M, that is, M = [M zM]Tz^β. Moreover, any non-trivial invariant subspace M of Hβ^2（D） is also generated by the quasi-wandering subspace PMTz^βM^⊥, that is, M = [PMTz^βM^⊥]Tz^β.

关键词： Hardy-Sobolev space invariant subspace wandering subspace quasi-wandering sub- space Beurling type theorem