由气水流场耦合求解圆板的垂直等速入水

为探讨气流对入水空泡的影响以及计算非定常空泡面上的压力分布，本文提出了一个用自由面和物面上的边值同时求解气、水流场的方法，对圆板垂直等速入水算例，获得了空泡深闭合的结果。空泡内压力在深闭合时的骤增趋势与实验一致。表明本方法用于计算存在自由面的二层不掺混不可压势流问题是有效的。     

Octanoic Acid—An Insecticidal Metabolite of Conidiobolus coronatus (Entomopthorales) That Affects Two Majors Antifungal Protection Systems in Galleria mellonella (Lepidoptera): Cuticular Lipids and Hemocytes

The food flavour additive octanoic acid (C8:0) is also a metabolite of the entomopathogenic fungus Conidiobolus coronatus, which efficiently infects and rapidly kills Galleria mellonella. GC-MS analysis confirmed the presence of C8:0 in insecticidal fraction FR3 extracted from C. coronatus filtrate. Topical administration of C8:0 had a dose-dependent effect on survival rates of larvae but not on pupation or adult eclosion times of the survivors. Topically applied C8:0 was more toxic to adults than larvae (LD100 for adults 18.33 ± 2.49 vs. 33.56 ± 2.57 µg/mg of body mass for larvae). The administration of C8:0 on the cuticle of larvae and adults, in amounts corresponding to their LD50 and LD100 doses, had a considerable impact on the two main defense systems engaged in protecting against pathogens, causing serious changes in the developmental-stage-specific profiles of free fatty acids (FFAs) covering the cuticle of larvae and adults and damaging larval hemocytes. In vitro cultures of G. mellonella hemocytes, either directly treated with C8:0 or taken from C8:0 treated larvae, revealed deformation of hemocytes, disordered networking, late apoptosis, and necrosis, as well as caspase 1–9 activation and elevation of 8-OHdG level. C8:0 was also confirmed to have a cytotoxic effect on the SF-9 insect cell line, as determined by WST-1 and LDH tests.     

土钉支护结构中土钉长度的设计研究

土钉支护结构由于其诸多优点在深基坑中得到广泛应用,但是土钉长度布置问题一直是一个热点问题。本文研究了土钉长度的布置方式,结合工程实践,基于内部整体稳定性安全系数最小值的限制原则分析了土钉钻孔直径、水平倾角以及土钉间距等设计参数对土钉长度的影响,最后分析了不同土钉长度布置方式对安全系数的影响,所得结论可供工程技术人员参考。     

Alchemical Design of Pharmacological Chaperones with Higher Affinity for Phenylalanine Hydroxylase

Phenylketonuria (PKU) is a rare metabolic disease caused by variations in a human gene, PAH, encoding phenylalanine hydroxylase (PAH), and the enzyme converting the essential amino acid phenylalanine into tyrosine. Many PKU-causing variations compromise the conformational stability of the encoded enzyme, decreasing or abolishing its catalytic activity, and leading to an elevated concentration of phenylalanine in the blood, which is neurotoxic. Several therapeutic approaches have been developed to treat the more severe manifestations of the disorder, but they are either not entirely effective or difficult to adhere to throughout life. In a search for novel pharmacological chaperones to treat PKU, a lead compound was discovered (compound IV) that exhibited promising in vitro and in vivo chaperoning activity on PAH. The structure of the PAH-IV complex has been reported. Here, using alchemical free energy calculations (AFEC) on the structure of the PAH-IV complex, we design a new generation of compound IV-analogues with a higher affinity for the enzyme. Seventeen novel analogues were synthesized, and thermal shift and isothermal titration calorimetry (ITC) assays were performed to experimentally evaluate their stabilizing effect and their affinity for the enzyme. Most of the new derivatives bind to PAH tighter than lead compound IV and induce a greater thermostabilization of the enzyme upon binding. Importantly, the correspondence between the calculated alchemical binding free energies and the experimentally determined ΔΔG_b values is excellent, which supports the use of AFEC to design pharmacological chaperones to treat PKU using the X-ray structure of their complexes with the target PAH enzyme.     

OPTIMIZING LAYOUT OF URBAN STREET CANYON USING NUMERICAL SIMULATION COUPLING WITH MATHEMATICAL OPTIMIZATION

1. INTRODUCTION Vehicular emissions have become one of thmain sources of urban atmospheric pollution in Chinwith the development of the urban construction andthe increase in the number of vehicles. There are lots of factors influencing the transport and dispersion of vehicular exhausted pollutants and further influencing the local air quality, among which the gas dynamical effect due to the mechanical turbulence from huge buildings and street canyons is especially remarkable. Previous stu…     

矿井火区典型可燃气体对甲烷化学动力学的影响分析

为研究多元混合气体对CH₄爆炸过程的影响,选取矿井火区典型可燃气体CH₄、C₂H₆、C₂H₄、CO、H₂,利用CHEMKIN软件模拟分析了不同组分C₂H₆/C₂H₄/CO/H₂瓦斯混合气体爆炸反应过程。研究结果表明：随着混合气体组分中各可燃气体体积分数的增大,CH₄的爆炸压力和温度不断增高,CH₄体积分数和O₂体积分数迅速下降,点火延迟时间明显缩短;在爆炸产生的有毒有害气体中,CO的体积分数最高;H^*、OH^*自由基的体积分数持续增大,O^*自由基呈现先增大后减小的趋势。敏感性分析发现促进自由基生成的反应步主要是R38(H+O₂$ \\rightleftharpoons $O+OH)和R119(HO₂+CH₃$ \\rightleftharpoons $OH+CH₃O),抑制其生成的主要反应步为R98(OH+CH₄$ \\rightleftharpoons $CH₃+H₂O)和R53(H+CH₄$ \\rightleftharpoons $CH₃+H₂)。     

Evaluating the performance of a discrete manufacturing process using RFID: A case study

The material flow is a major focus point in improving productivity in today’s product diversified manufacturing organizations. Nevertheless, there is still a lack of efficient methods to control material flow through manufacturing processes in cases where multi-item tracking is difficult to achieve. This paper presents an RFID-based RTLS (Real-Time Location System) solution for obtaining multi-item work-in-process visibility within a manufacturer. It delivers detailed performance metrics through RTLS data analysis in order to evaluate workflow performance and to obtain a lean process. We pre-filter the RTLS data through the development of a middleware data collection method to acquire near real-time performance evaluation. A case study illustrates the complete process including measurements before and after a workflow redesign. The increased level of detail from RFID measurements yields new insights into shop floor actions and the real effects of redesign efforts.     

能量管理系统中电网潮流单线图自动生成算法

大规模电力系统的潮流图自动生成问题是一个高度复杂的优化问题,可以分解为厂站自动布局和自动布线问题.对于厂站布局问题,文中引入了引力一斥力模型进行优化,可以快速得到较好的布局效果.在此基础上,再利用遗传算法进一步优化.对于自动布线问题,文中首先引入了带虚拟引线的厂站图标定义,以便于出线布局;然后,采用迷宫探索方法对线路进行横平竖直的自动布线;最后,在变电站出线端自动加上开关元件从而得到最终的图形.针对某省级电网模型的测试表明了所提出的方法的有效性.