检索结果-南通市图书馆

Photoproduction of multi-meson final states–recent results from the Crystal-Barrel/TAPS experiment at ELSA-

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2009年第12期33卷 1105-1112页

作者： U. thoma HISKP Universitt Bonn Nussallee 14-16 53115 Bonn Germany

Multi-meson final states such as γp →pπ0π0 and γp →pπ0η have been investigated with the Crystal-Barrel/TAPS experiment at ELSA. Baryon cascades via △π and △η and also via higher mass baryon resonances are clearly observed. Based on this data and on data from other reactions a partial wave analysis has been performed from which partial decay widths of various N＊ and △＊ states into the different pπ0π0 and pπ0η decay channels have been determined, leading partly to unexpected results. In addition, polarisation observables have been investigated. The beam asymmetry X has been determined for both reactions and double polarisation data using a longitudinally polarised target and a circularly or linearly polarised photon beam has been taken. Given the angular coverage of the Crystal-Baxrel/TAPS experiment this data covers almost the full angular range and phase space. This data will provide new and important information for the partial wave analyses and bring us one step closer towards a complete experiment.

关键词： baryon spectroscopy photoproduction multi-meson final states polarisation observables

在线全文

学校读者我要写书评

暂无评论

通过加氢裂化提高柴油质量

石化译文 1994年第2期 77-79页

作者： thoma.,D 楼月华

Jordan—Schonflies定理和曲面的分类

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

现代科技译丛（大连） 1993年第2期 69-71页

作者： thoma.,C 何碧英

Formulation of carbon black-ionomer dispersions for thin film formation in fuel cells

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2019年第3期17卷 7-21页

作者： Eva Hoffmann Su Zhang Martin thoma.Cornelia Damm Wolfgang Peukert Institute of Particle Technology (LFG) Friedrich-Alexander-Universitat Erlangen-Niimberg (FAU) CauerstraJSe 4 D-91058 Erlangen Germany

The performance of proton exchange membrane fuel cells (PEMFC) is strongly determined by the structure and composition of the electrode *** interactions between the ionomer,carbon black particles,and solvent affect the suspension properties and thus the layer *** analyze the effect of the ionomer-to-carbon (I/C) weight ratio for two different types of carbon black on the suspension and layer *** branched carbon blacks with a high surface area tend to form less cracked *** less branched carbons can pack together more closely,a smaller pore size results in a larger capillary pressure during drying and thus more *** added ionomer adsorbs on the carbon particles and improves the colloidal stability of the carbon black *** carbon black aggregates are thus smaller,resulting in closer packing and thinner ***,the addition of the ionomer increases the critical coating thickness (CCT) of the layers because drying stresses are dissipated by the deformation of the ionomer,preventing crack *** optimum I/C weight ratio is identified for optimal layer formation and minimized crack formation.

关键词： Perfluorosulfonic acid (PFSA) ionomer Carbon black Layer formation Cracking Porosity

Ultrasound enhanced friction stir welding of aluminum and steel： Process and properties of EN AW 6061/DC04-Joints

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 Materials Science & Technology 2018年第1期34卷 163-172页

作者： Marco thoma.Guntram Wagner Benjamin Straβ Bernd Wolter Sigrid Benferc Wolfram Furbeth Chair of Composites and Material Compounds Chemnitz University of Technology Chemnitz 09125 Germany Fraunhofer Institute for Nondestructive Testing IZFP Saarbrucken 66123 Germany DECHEMA-Forschungsinstitut Frankfurt am Main 60486 Germany

In this work, the joining of aluminum to steel was conducted by ultrasound enhanced friction stir weld- ing （USE-FSW）. The power ultrasound was introduced into one of the metal sheets by an ultrasonic roll seam module synchronously to the FSW-process. The effect of the ultrasound on the resulting welds, their microstructure and their corrosion properties was investigated by light and scanning electron microscopy and corrosion investigations. The USE-FSW-joints showed less and smaller steel particles in the nugget zone as well as a thinner continuous intermetallic phase of FeAl3 at the interface. The nondestructive testing method of computed laminography proved the observations made by optic microscopy due to non-porous joints for both techniques. Corrosion investigations showed only low corrosion current densities and no enhanced galvanic corrosion for the EN AW-6061/DC04-hybrid joints in sodium chloride solution.

关键词： Friction stir welding Ultrasound enhancement Dissimilar joints Corrosion

在线全文

学校读者我要写书评

暂无评论

一种低压电容式压力—电传感器

仪器仪表与分析监测 1986年第1期 32-36页

作者： PAULE. thoma. ROSEMARY STEWART. JEANNIne O. COLLA 邱嗣鑫裴锡安

前言研究多种多样的电输出压力传感器是为了进行众多不同工作原理的压力测量。实际上,所有压力—电(P-E)传感器都由一个能将流体压力转换为机械位移或者力的流体压力敏感元件所组成。再将这种机械位移或者力转换成一个电输出。压力一电... 详细信息

前言研究多种多样的电输出压力传感器是为了进行众多不同工作原理的压力测量。实际上,所有压力—电(P-E)传感器都由一个能将流体压力转换为机械位移或者力的流体压力敏感元件所组成。再将这种机械位移或者力转换成一个电输出。压力一电传感器的最普通的电输出是电阻的、电容的、电感的和磁阻的变化。

关键词：电传感器导电层厚度电容式微微法低压电压

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

齿轮泵在橡胶挤出工艺中的应用

橡胶工业 2003年第8期50卷 491-492页

作者： Olaf Skibba Oliver thoma.田军涛 AZ模具和机器制造公司

齿轮泵技术在橡胶工业中的应用正取得突飞猛进的发展.橡胶挤出中使用齿轮泵有很多优点,如可提高产品质量和减少胶料焦烧等.事实上,如果多花一点时间改进和优化技术,同时应用更多必要的范例来了解齿轮泵的用途,将很难想象在下一代挤出生... 详细信息

齿轮泵技术在橡胶工业中的应用正取得突飞猛进的发展.橡胶挤出中使用齿轮泵有很多优点,如可提高产品质量和减少胶料焦烧等.事实上,如果多花一点时间改进和优化技术,同时应用更多必要的范例来了解齿轮泵的用途,将很难想象在下一代挤出生产线中可以不用齿轮泵.这主要是由于单螺杆挤出机有限的生产能力造成的.

关键词：齿轮泵橡胶挤出工艺应用单螺杆挤出机边界条件

Assessment of Uinta Basin Oil and Natural gas Well Pad Pneumatic Controller Emissions

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Protection 2017年第4期8卷 394-415页

作者： Eben D. thoma.Parikshit Deshmukh Russell Logan Michael Stovern Chris Dresser Halley L. Brantley Office of Research and Development National Risk Management Research Laboratory U.S. EPA Durham NC USA Jacobs Technology Inc. Durham NC USA Region 8 U.S. EPA Denver CO USA ORISE Participant U.S. EPA Office of Research and Development National Risk Management Research Laboratory Durham NC USA

In the fall of 2016, a field study was conducted in the Uinta Basin Utah to improve information on oil and natural gas well pad pneumatic controllers (PCs) and emission measurement methods. A total of 80 PC systems at five oil sites (supporting six wells) and three gas sites (supporting 12 wells) were surveyed, and emissions data were produced using a combination of measurements and engineering emission estimates. Ninety-six percent of the PCs surveyed were low actuation frequency intermittent vent type. The overall whole gas emission rate for the study was estimated at 0.36 scf/h with the majority of emissions occurring from three continuous vent PCs (1.1 scf/h average) and eleven (14%) malfunctioning intermittent vent PC systems (1.6 scf/h average). Oil sites employed, on average 10.3 PC systems per well compared to 1.5 for gas sites. Oil and gas sites had group average PC emission rates of 0.28 scf/h and 0.67 scf/h, respectively. This difference was due in part to differing site selection procedures used for oil and gas sites. The PC system types encountered, the engineering emissions estimate approach, and comparisons to measurements are described. Survey methods included identification of malfunctioning PC systems and emission measurements with augmented high volume sampling and installed mass flow meters, each providing a somewhat different representation of emissions that are elucidated through example cases.

关键词： Pneumatic Controller Emissions Oil and Natural gas Production Uinta Basin Methane Volatile Organic Compounds

基于亚波长空间分辨平面太赫兹谐振器的二维频率分辨成像

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

长春理工大学学报（自然科学版） 2012年第3期35卷 141-144,153页

作者： Arne thoma.thoma. Dekorsy 德国康斯坦茨大学物理系及应用光子学中心

利用基于扫描遂道显微成像技术的无孔(散射)近场太赫兹时域显微镜,对由非对称开口谐振环(SRR)构成的频率选择表面(FSS)的单元进行了研究。利用高速非同步光学采样法,在宽频率范围(0.3…1THz)内获得了l/60-l/200的高频独立分辨率的图像... 详细信息

利用基于扫描遂道显微成像技术的无孔(散射)近场太赫兹时域显微镜,对由非对称开口谐振环(SRR)构成的频率选择表面(FSS)的单元进行了研究。利用高速非同步光学采样法,在宽频率范围(0.3…1THz)内获得了l/60-l/200的高频独立分辨率的图像显示。该图像给出了谐振环的弧状结构,另外,还显示了谐振环的弧末端周围的信号增强。结果显示,从两个不同弧发出的相对近场信号强度的特性与SRRs本征共振频率是相关联的。

关键词：近场呈像太赫兹开口谐振环时域光谱