DHDECMP-TBP/煤油萃取 HNO_3-稀土过程中防止形成第二有机相的研究

研究了ＤＨＤＥＣＭＰ－ＴＢＰ／煤油萃取ＨＮＯ３后形成和防止形成第二有机相的各影响因素。以Ｇｄ代表稀土，探讨了ＤＨＤＥＣＭＰ－ＴＢＰ／煤油萃取稀土时ＤＨＤＥＣＭＰ浓度、ＴＢＰ浓度、水相ＨＮＯ３浓度和温度对有机相萃取负载量的影响。结果表明：０．６０ｍｏｌ／ＬＤＨＤＥＣＭＰ－１．４０ｍｏｌ／ＬＴＢＰ／煤油能有效避免第二有机相的形成，又能满足工艺负载量的要求。     

Neueste Entwicklungen beim baulichen Brandschutz von Straßentunneln

In der jüngeren Vergangenheit hat sich gezeigt, dass Straßen tunnel durch größere Brände in erheblichem Umfang geschädigt werden können. In der Folge wurden verschiedene internationale Forschungsprojekte durchgeführt, um den baulichen Brandschutz von Straßentunneln weiterzuentwickeln. Aufbauend auf den internationalen Forschungsprojekten wurden vom BMVBS und der BASt drei nationale Forschungsprojekte zum baulichen Brandschutz von Straßentunneln initiiert. In diesen Projekten wurden vorhandene Temperatur‐Zeit‐Verläufe (sog. “Brandkurven”) für Straßentunnel, Brandver suche in Tunneln und reale Brände in Straßentunneln im Hinblick auf eine mögliche Anwendung zur Bemessung des baulichen Brandschutzes von Straßentunneln analysiert. Außerdem wurden die Temperatureindringung in die Tunnelinnenschale und die Tragfähigkeit von üblichen Tunnelquerschnitten infolge Brandeinwirkung numerisch ermittelt. Schließlich wurde anhand von Brandversuchen an großmaßstäblichen Probekörpern die Wirkung von PP‐Faserbeton auf das Abplatzverhalten von Innenschalenbeton untersucht. Über das Vorgehen und die Ergebnisse dieser Forschungsprojekte wird im Folgenden berichtet. Latest developments for structural fire protection of road tunnels. In the recent past it was shown that road tunnels can be damaged severely by large fires. For that reason several international research projects were carried out for further development of structural fire protection of road tunnels. Based on international research projects three national research projects were initiated by the Federal Ministry of Transport, Building and Urban Development (BMVBS) and the Federal Highway Research Institute (BASt). In the course of these projects existing temperature‐time‐progressions (so called ”fire curves”) for road tunnels, fire tests in tunnels and real fires in road tunnels were analyzed with regard to a possible application for the design of structural fire protection of road tunnels. Furthermore the temperature penetration in the tunnel lining and the load bearing capacity of usual tunnel sections were numerically examined under fire influence. Finally the influence of fiber‐modified concrete on the effect of explosive spalling was investigated by means of large scale fire tests on specimens made of concrete for tunnel lining. In the following procedures and results of the national research projects are described.     

论限矩型液力偶合器与笼形电机和工作机负载的合理匹配

根据生产运行的实际经验，提出了在胶带输送系统中液力偶合器与电机外特性的合理匹配，液力偶合器与电机和硬齿面减速器连接结构的合理匹配。     

Preliminary investigation of near-field nondestructive testing of carbon-loaded composites using loaded open-ended waveguides

Composite materials are being utilized in a multitude of industrial and commercial applications. This is due to their desirable features such as light weight, durability and strength. This presents quite a challenge to the field of nondestructive testing and evaluation (NDT&E). Due to the material complexity associated with these materials, many techniques have been shown to be ineffective when inspecting these materials. The ability of microwaves to penetrate deeply inside such dielectric materials and composites makes microwave NDT techniques very attractive for interrogating such materials. Microwaves are also sensitive to the presence of dissimilar layers in these materials which allows for accurate thickness variation measurement in the range of a few micrometers at frequencies as low as 10 GHz. Near-field microwave inspection techniques were successfully used for detecting and locating defects and voids of different sizes and shapes in composites. For optimal detection, the standoff distance between the sensor and the composite and frequency of operation were used as optimization parameters to improve the detection capability. Carbon-loaded composites present a challenge to microwave NDT because of the lossy nature of carbon, especially at high microwave frequencies. Lower frequencies penetrate more (deeper) in carbon-loaded composites, however, the size of the waveguide sensor increases drastically at lower frequencies and consequently the resolution degrades rapidly as well. To overcome this dilemma, open-ended rectangular waveguides loaded with a dielectric material will be used to inspect carbon-loaded composites. The loading of the waveguide reduces the frequency of operation and keeps the small size of the waveguide (i.e. increases the penetration depth and maintains the resolution). Carbon-loaded composites with disbonds will be inspected and the ability of utilizing loaded rectangular waveguides for carbon-loaded composites inspection will be assessed.     

少齿差行星减速器孔销式输出机构的强度和刚度初探

少齿差行星减速器的孔销式输出机构是制约减速器承载能力主要的环节之一,主要是销轴、销孔间接触强度、刚度及销轴的弯曲强度、刚度所致。而它的力学计算属于超静定问题。这里分别采用材料力学的方法和弹性力学有限元方法及分析软件COSMOSDesignSTAR分析销轴及与其相关零件的强度和刚度的结果,目的是找出提高减速器承载能力的途径。     

负载型纳米催化剂催化合成丁酸苄酯的性能

用水热法合成磁性纳米Fe3O4,通过浸渍法和超声法制得S2O8^2-／Fe3O4负载型磁性纳米催化剂,进而催化合成丁酸苄酯,研究了催化剂的负载量、活化温度对反应的影响,讨论了催化剂回收和重复利用等性能。结果表明,采用浸渍法合成的负载型催化剂催化合成丁酸苄酯,酯化率达85．6％,粗产品纯度达94．1％;采用超声法制备的催化剂在选择性上则显示出较大的优势。     

Effects of anchoring tensile stresses in axially loaded plates and sections

Thin-walled compression members are commonly designed on the assumption that the loaded edges remain straight. Under this assumption, tensile stresses develop in the most flexible parts of the component plates at advanced local buckling deformation, and thus are assumed to be ‘anchored’ at the ends. However, current design rules for plate elements, such as the Winter formulae, are partly based on tests in which the load was applied by use of rigid platens that did not permit tensile stresses to develop. There exists an apparent inconsistency between the assumption of straight loaded edges and the use of a design curve calibrated from tests in which the loaded edges of component plates may not have remained straight.This paper addresses this apparent inconsistency by comparing finite element solutions for the conditions of straight loaded edges and loading by use of a contact surface between the plate edge and a non-deformable rigid body end platen, where there is no constraint for the plate edge to remain in contact with the rigid body. Solutions are provided for a single half-wavelength of unstiffened and stiffened plate elements simply supported along three and four edges, respectively. The effect of multiple half-wavelengths is also investigated, as is the effect of interaction between elements in practical sections comprising stiffened and unstiffened elements.     

侧向变位PHC管桩竖向承载力的分析与计算

近年来,对PHC管桩的各项性能的研究已日趋完善,但对于侧向变位PHC管桩的承载力研究的较少。实际工程中的基桩大都处于非理想受荷状态,各种的侧向变位对承载力有不同程度的影响。当入土的管桩在施加竖向荷载前存在一定的倾斜时,所施加的荷载就会在桩身中造成附加弯曲变形。本文分别以PHC管桩桩身截面抗拉、抗压强度为强度控制因素,应用横向受荷桩的通解法计算不同倾斜情况下管桩的内力矩,再结合竖向荷载推导承载力公式。     

燕北地区商品混凝土早期裂缝的主要成因与预防措施

混凝土结构产生裂缝是一个很普遍的现象.裂缝在结构物表面可分为网状裂缝、爆裂状裂缝、不规则短裂缝、纵向裂缝、横向裂缝、斜裂缝等,裂缝按其产生的原因,分为荷载裂缝和变形裂缝.荷载裂缝是指因动、静荷载的直接作用引起的裂缝.变形裂缝是指因不均匀沉降、温度变化、湿度变异、膨胀、收缩、徐变等变形因素引起的裂缝.一般来说荷载裂缝与设计和施工有关,变形裂缝则与材料及配合比以及施工养护有关,很多裂缝的产生都不是一个因素造成,但主要原因要分清楚才能采取有效的控制预防措施.     

Heterogeneous photocatalytic degradation of ethylene glycol and propylene glycol

The photocatalytic decomposition of ethylene glycol and propylene glycol was investigated by using UV-illuminated TiO₂ and metal-loaded TiO₂ catalysts. The effects of pH, initial concentration, and wavelength of light on the decomposition rate of the glycols were explored. Platinum-and palladium-loaded TiO₂ catalysts enhanced the rates of photodecomposition compared to unloaded TiO₂. The glycols were oxidized primarily to carbon dioxide and water. Formaldehyde was found to be an important reaction intermediate. A detailed chemical reaction mechanism for the destruction of ethylene glycol and propylene glycol in water via free radical pathway and trapped hole reactions at the particle surface is proposed.