螺旋焊线管局部噘嘴应力集中分析

螺旋焊缝局部噘嘴问题是复杂的三维问题，至今没有现成的安全评定公式可以利用，也难以获得纯粹的理论解。应“西气东输”工程之需，本文利用现有直焊缝理论基础，建立了该问题的力学模型，获得了应力集中因子的显式解，给制订螺旋焊线管几保缺陷的安全评定标准提供了理论基础。利用商用有限元工具ABAQUS对螺旋焊线局部噘嘴进行的系统分析显示，本文提供的理论解具有很强的预测能力。     

Multilinear target-based decision analysis with hybrid-information targets and performance levels

Fuzzy Optimization and Decision Making - For several classes of decisions, the use of target-based decision analysis (TBDA) is more appropriate than utility analysis. Recent literature on TBDA...     

Deactivation of Cu-Exchanged Automotive-Emission NH3-SCR Catalysts Elucidated with Nanoscale Resolution Using Scanning Transmission X-ray Microscopy

To gain insight into the underlying mechanisms of catalyst durability for the selective catalytic reduction (SCR) of NO_x with an ammonia reductant, we employed scanning transmission X-ray microscopy (STXM) to study Cu-exchanged zeolites with the CHA and MFI framework structures before and after simulated 135 000-mile aging. X-ray absorption near-edge structure (XANES) measurements were performed at the Al K- and Cu L-edges. The local environment of framework Al, the oxidation state of Cu, and geometric changes were analyzed, showing a multi-factor-induced catalytic deactivation. In Cu-exchanged MFI, a transformation of Cu^II to Cu^I and Cu_xO_y was observed. We also found a spatial correlation between extra-framework Al and deactivated Cu species near the surface of the zeolite as well as a weak positive correlation between the amount of Cu^I and tri-coordinated Al. By inspecting both Al and Cu in fresh and aged Cu-exchanged zeolites, we conclude that the importance of the preservation of isolated Cu^II sites trumps that of Brønsted acid sites for NH₃-SCR activity.     

Natural radioactivity in some building materials and by-products of Shaanxi, China

The concentration of ²²⁶Ra, ²³²Th and ⁴⁰K has been determined by -ray spectrometry. The measured activity in the selected building materials and by-products of coal fired power plants ranges from 21.5 to 91.3 Bq·kg^–1, 15.4 to 63.2 Bq·kg^–1 and 83.2 to 683.9 Bq·kg^–1 for ²²⁶Ra, ²³²Th and ⁴⁰K, respectively. The results were compared with the reported data of other countries and with the world average activity of soil. The radium equivalent activities values of all building materials are lower than the limit of 370 Bq·kg^–1, equivalent to a -dose of 1.5 mSv·y^–1. The values of the external hazard index and the internal radiation hazard index are less than unity.This work was supported by the Provincial Natural Sciences Foundation of Shaanxi through Grants 2003D04 and by the Science Foundation of Shaanxi Normal University. Gratitude is expressed to J. Xiaowei, W. Xiaolei, L. Zhendong for assisting in sampling.     

Rh-catalyzed C–N coupling of N-sulfonyl-1,2,3-trizales with secondary amines for regioselective synthesis of phenylvinyl-1,2-diamines

Abstract

An efficient and operationally simple method for the preparation of phenylvinyl-1,2-diamines by the Rh(II)-catalyzed C–N coupling of 1-sulfonyl-1H-1,2,3-triazoles with secondary amines (e.g., N-aryl glycine esters, diarylamines or 1-phenyl-2-(p-tolylamino)ethanone) via the 1,3-insertion of Rh(II)-azavinyl carbenes into sp ³ N-H bond process has been developed. The optimized conditions tolerate various functional groups and afford the diverse (Z)-phenylvinyl-1,2-diamines in good to excellent yields with high regioselectivity. The method was also successfully extended to the synthesis of functional tertiary amines having a Z configuration of the (1-aryl-2-(sulfonamido)vinyl) substituent and two aryl groups.     

Structural studies of 1-butyl-3-methylimidazolium tetrafluoroborate/TX-100/ p-xylene ionic liquid microemulsions.

The ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF4) forms nonaqueous microemulsions with p-xylene, with the aid of the nonionic surfactant TX-100. The phase behavior of the ternary system is investigated, and three microregions of the microemulsions-ionic liquid-in-oil (IL/O), bicontinuous, and oil-in-ionic liquid (O/IL)-are identified by conductivity measurements, according to percolation theory. On the basis of a phase diagram, a series of IL/O microemulsions are chosen and characterized by dynamic light scattering (DLS). The size of aggregates increases on increasing the amount of added polar component (bmimBF(4)), which is a similar phenomenon to that observed for typical water-in-oil (W/O) microemulsions, suggesting the formation of IL/O microemulsions. The microstructural characteristics of the microemulsions are investigated by FTIR and 1H NMR spectroscopy. The results indicate that the interaction between the electronegative oxygen atoms of the oxyethylene (OE) units in TX-100 and the electropositive imidazolium ring may be the driving force for the solubilization of bmimBF4 into the core of the TX-100 aggregates. In addition, the micropolarity of the microemulsions is investigated by using methyl orange (MO) as a UV/Vis spectroscopic probe. A relatively constant polarity of the microemulsion droplets is obtained in the IL microemulsion. Finally, a plausible structure for the IL/O microemulsion is presented.     

生物降解型聚氨酯研究进展

本文综述了生物降解型聚氨酯的研究现状，并探讨了影响其生物降解性的因素，指出了其应用前景，特别是医学上的应用．     

The influence of dielectric layer on the thermal boundary resistance of GaN-on-diamond substrate

The cooling behavior of GaN-on-diamond substrate can be enhanced by reducing the thermal boundary resistance (TBR), which is mainly determined by the nature of interlayer. Although SiN film is considered as the primary candidate of dielectric layer, it is still needed to be optimized. In order to facilitate the understanding of the influence of dielectric layer on the TBR of GaN-on-Diamond substrate, aluminum nitride (AlN), and silicon nitride (SiN) film were compared systematically, both of which are 100 nm. The time-domain thermoreflectance (TDTR) measurements, adhesion evaluation, and microstructural analysis methods were adopted to analyse these two interlayers. The results show the TBR of SiN interlayer is as low as 38.5 ± 2.4 m²K GW⁻¹, comparing with the value of 56.4 ± 5.5 m²K GW⁻¹ for AlN interlayer. The difference of TBR between these two interlayers is elucidated by the diamond nucleation density, and the adhesion between the diamond film and GaN substrate, both of which are affected by the surface charge and chemical groups of the dielectric layer.     

丁螺环酮联合草酸艾司西酞普兰 治疗抑郁症的增效作用和安全性 观察

目的 探讨丁螺环酮联合草酸艾司西酞普兰治疗抑郁症的增效作用和安全性。方法 选取符合ICD-10 抑郁发作 诊断标准,经草酸艾司西酞普兰足量（20mg/d）、足疗程（6周）治疗未获得痊愈的45 例抑郁症患者,加用丁螺环酮15~60mg/d,观察8周,并分别在治疗前、治疗后第1、4、8周末分别评估汉密尔顿抑郁量表（HAMD）和汉密尔顿焦虑量表（HAMA）,以第1周末HAMA 评分≤7分为界,分为焦虑控制组（HAMA 评分≤7 分）和焦虑未控制组（HAMA 评分＞7 分）;以8周末HAMD≤7分为标准,分为获得痊愈组（HAMD≤7 分）和未获得痊愈组（HAMD＞7 分）;并在治疗第1、4、8周末分别评估不良反应。结果 在治疗第4周,获得痊愈20 例（44.4%）,第8 周末获得痊愈25 例（55.5%）。治疗后第4、8 周,获得痊愈组的患者HAMA 评分明显低于未获得痊愈组（P＜0.05）。治疗后第1、4周,焦虑控制组和焦虑未控制组患者HAMD 评分比较差异无统计学意义,治疗后第8 周,两组患者HAMD 评分 比较差异有统计学意义（P＜0.05）。不良反应以口干（40.0%）、便秘（36.9%）及乏力（13.3%）为多见。结论 经草酸艾司西酞普兰足量、足疗程治疗后仍未彻底痊愈的患者加用丁螺环酮可进一步获得疗效,提高痊愈率,安全性良好。     

A null-space primal-dual interior-point algorithm for nonlinear optimization with nice convergence properties

We present a null-space primal-dual interior-point algorithm for solving nonlinear optimization problems with general inequality and equality constraints. The algorithm approximately solves a sequence of equality constrained barrier subproblems by computing a range-space step and a null-space step in every iteration. The ℓ₂ penalty function is taken as the merit function. Under very mild conditions on range-space steps and approximate Hessians, without assuming any regularity, it is proved that either every limit point of the iterate sequence is a Karush-Kuhn-Tucker point of the barrier subproblem and the penalty parameter remains bounded, or there exists a limit point that is either an infeasible stationary point of minimizing the ℓ ₂ norm of violations of constraints of the original problem, or a Fritz-John point of the original problem. In addition, we analyze the local convergence properties of the algorithm, and prove that by suitably controlling the exactness of range-space steps and selecting the barrier parameter and Hessian approximation, the algorithm generates a superlinearly or quadratically convergent step. The conditions on guaranteeing that all slack variables are still positive for a full step are presented.