检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

具有发展前途的治疗心衰的新强心剂

国外医药（合成药．生化药．制剂分册） 1989年第4期10卷 209-211页

作者： wetzel b 汪啸洋

充血性心力衰竭是一种常见病,也是医学上的难题。虽然总体上心血管疾病的死亡率在下降,但由心衰引起的死亡率却在不断增加。充血性心力衰竭的治疗,除了使用增强心肌收缩力的药物强心药外,还趋向使用血管舒张药来减少血管的阻力以及使用... 详细信息

充血性心力衰竭是一种常见病,也是医学上的难题。虽然总体上心血管疾病的死亡率在下降,但由心衰引起的死亡率却在不断增加。充血性心力衰竭的治疗,除了使用增强心肌收缩力的药物强心药外,还趋向使用血管舒张药来减少血管的阻力以及使用利尿药来减少循环血容量。强心甙是应用多年合成的的强心药,但其安全范围小,而数千种合成的强心甙类似物疗效没有显著的改善。

关键词：心力衰竭强心剂氨力农米力农

pde2path – A Matlab Package for Continuation and bifurcation in 2D Elliptic Systems

在线全文

学校读者我要写书评

暂无评论

Numerical Mathematics(Theory,Methods and Applications) 2014年第1期7卷 58-106页

作者： Hannes Uecker Daniel wetzel Jens D.M.Rademacher Institut für Mathematik Universität Oldenburg26111 OldenburgGermany Universität bremen Fachbereich MathematikPostfach 33044028359 BremenGermany

pde2path is a free and easy to use Matlab continuation/bifurcation package for elliptic systems of PDEs with arbitrary many components,on general two dimensional domains,and with rather general boundary *** package is based on the FEM of the Matlab pdetoolbox,and is explained by a number of examples,including bratu’s problem,the Schnakenberg model,Rayleigh-bénard convection,and von Karman plate *** serve as templates to study new problems,for which the user has to provide,via Matlab function files,a description of the geometry,the boundary conditions,the coefficients of the PDE,and a rough initial guess of a *** basic algorithm is a one parameter arclength-continuation with optional bifurcation detection and *** calculations,error control and mesh-handling,and some elementary timeintegration for the associated parabolic problem are also *** continuation,branch-switching,plotting etc are performed via Matlab command-line function calls guided by the AUTO *** software can be downloaded from ***/*** ker/pde2path,where also an online documentation of the software is provided such that in this paper we focus more on the mathematics and the example systems.

关键词： Elliptic systems continuation and bifurcation finite element method

balanced and Unbalanced Components of Moist Atmospheric Flows with Phase Changes

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

Chinese Annals of Mathematics,Series b 2019年第6期40卷 1005-1038页

作者： Alfredo N.wetzel Leslie M.SMITH Samuel N.STECHMANN Jonathan E.MARTIN Department of Mathematics University of Wisconsin-MadisonMadisonWI 53706USA Department of Mathematics and Department of Engineering Physics University of Wisconsin-MadisonMadisonWI 53706USA Department of Mathematics and Department of Atmospheric and Oceanic Sciences University of Wisconsin-MadisonMadisonWI 53706USA Department of Atmospheric and Oceanic Sciences University of Wisconsin-MadisonMadisonWI 53706USA

Atmospheric variables(temperature, velocity, etc.) are often decomposed into balanced and unbalanced components that represent low-frequency and high-frequency waves, respectively. Such decompositions can be defined, for instance, in terms of eigenmodes of a linear operator. Traditionally these decompositions ignore phase changes of water since phase changes create a piecewise-linear operator that differs in different phases(cloudy versus non-cloudy). Here we investigate the following question: How can a balanced–unbalanced decomposition be performed in the presence of phase changes? A method is described here motivated by the case of small Froude and Rossby numbers,in which case the asymptotic limit yields precipitating quasi-geostrophic equations with phase changes. Facilitated by its zero-frequency eigenvalue, the balanced component can be found by potential vorticity(PV) inversion, by solving an elliptic partial differential equation(PDE), which includes Heaviside discontinuities due to phase changes. The method is also compared with two simpler methods: one which neglects phase changes, and one which simply treats the raw pressure data as a streamfunction. Tests are shown for both synthetic, idealized data and data from Weather Research and Forecasting(WRF) model simulations. In comparisons, the phase-change method and no-phase-change method produce substantial differences within cloudy regions, of approximately 5K in potential temperature, due to the presence of clouds and phase changes in the data. A theoretical justification is also derived in the form of a elliptic PDE for the differences in the two streamfunctions.

关键词： Potential vorticity inversion Moist atmospheric dynamics Slow-fast systems balanced-unbalanced decomposition Elliptic partial differential equations

Validation of atmospheric chemistry measurements from MIPAS,SCIAMACHY,GOMOS onboard ENVISAT by observations of balloon-borne MIPAS-b

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2010年第10期53卷 1533-1541页

作者： wetzel G OELHAF H FRIEDL-VALLON F KLEINERT A LENGEL A MAUCHER G NORDMEYER H GRUNOW K FISCHER H Institute for Meteorology and Climate Research(IMK) Karlsruhe Institute of Technology(KIT) Senate Department for Health Environment and Consumer Protection

In order to validate the atmospheric chemistry measurements by MIPAS,SCIAMACHY,and GOMOS onboard the ENVISAT,three flights of the balloon-borne Michelson Interferometer for Passive Sounding(MIPAS-b) were carried out in 2002 and 2003 at Aire sur l'Adour(France 44°N,0°E) and Esrange,Kiruna(Sweden 68°N,21°E).The validation campaign activities are summarized in this *** MIPAS-b instrument and its data processing procedure as well as the validation approaches are discussed in *** satellite and balloon measurements are matched with high coincidence in time and space,allowing a coincident approach to be applied for their ***,a trajectory model is used to confirm and enhance the statistical significance of the *** validation results show that MIPAS measurements of accuracy for temperature,H2O,O3,HNO3,CH4,N2O,and NO2 are good in the altitude range of 8-39 km(No2,22-39 km).And the precision is good between the altitudes of 15-33 km(No2,22-23 km).However,some exceptions were also found for temperature,H2O,HNO3,and *** SCIAMACHY data of accuracy for O3 and NO2 are within expectations between the altitudes 9-38 km except for O3 in 28-38 *** GOMOS data about O3 and NO2 are promising according to the preliminary comparison results.

关键词： validation ENVISAT MIPAS SCIAMACHY GOMOS MIPAS-b

道路用中重型增压柴油机动力总成的瞬态行驶循环建模

在线全文

学校读者我要写书评

暂无评论

汽车与新动力 2013年第6期45卷 38-43页

作者： birckett A Tomazic D bowyer S bevan K wetzel P Keidel S biller b 黄磊

用传统方法分析行驶循环燃油经济性时,运动学模型无法采集到增压空气处理系统中的瞬态差异。建立一维动力学性能仿真模型预测行驶循环燃油经济性,它包含了发动机和车辆模型的所有瞬态元素。令人感兴趣的瞬态技术是机械增压,其优点在于... 详细信息

用传统方法分析行驶循环燃油经济性时,运动学模型无法采集到增压空气处理系统中的瞬态差异。建立一维动力学性能仿真模型预测行驶循环燃油经济性,它包含了发动机和车辆模型的所有瞬态元素。令人感兴趣的瞬态技术是机械增压,其优点在于可改善增压响应,缩短达到最大扭矩的时间。评价了机械增压器离合器带来的好处。当前的美国6;级商用车市场只采用涡轮增压柴油机。根据对车辆销售和二手卡车市场进行调查的结果,选择了3辆车和基本型动力总成。行驶循环的燃油经济性是仿真工作的主要输出。所有动力总成都符合美国环保署2010年排放法规要求。同时包括2种降低氮氧化物的方法:（1）仅采用高比例废气再循环,（2）采用低比例废气再循环+选择性催化还原装置的后处理系统。在工作过程中开发了2种采用GT-Suite的新型建模方法。高水准的动力学模型对中央处理器性能强度的要求更高,但提供的输出不能用更快运行的稳态或运动学模型加以解释。机械增压配置对增压响应的改进体现在车辆性能的提高,而又不增加额定的功率/扭矩比。与基本型涡轮增压动力总成相比,机械增压应用不同水平的降速,既可提高车辆性能或燃油经济性,也可使两者同时得以改进。还评价了机械增压器的尺寸和布置方式（在串联增压配置中放在压气机之前或之后）,以及废气再循环回路的布置方式。在3辆车的应用中,均实现了燃油经济性的改善。

关键词：机械增压涡轮增压燃油经济性动力学模型废气再循环

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

地壳演化——一种同位素地球化学模式

地球与环境 1982年第11期 36-39页

作者： K.wetzel H.Schütze 唐月青

一、引言联系Taylor和Epstein(1962a、b)的研究,Garlik(1964)证实,岩浆岩、变质岩和矿物中的氧同位素组成首先与岩石和矿物的化学成分及形成温度有关。wetzel等(1979)指出,这个论断似乎也符合于沉积岩类。通过应用由Schütze(1980)制... 详细信息

一、引言联系Taylor和Epstein(1962a、b)的研究,Garlik(1964)证实,岩浆岩、变质岩和矿物中的氧同位素组成首先与岩石和矿物的化学成分及形成温度有关。wetzel等(1979)指出,这个论断似乎也符合于沉积岩类。通过应用由Schütze(1980)制定的计算同位素热力学效应的增量法,比过去在经验和半凭经验基础上所作的计算,已经能够比较准确地抓住硅酸

关键词：下地壳上地幔同位素地球化学同位素地质学地壳演化