丙酮提取菠萝皮抑菌物的条件研究

采用正交试验法研究丙酮提取菠萝皮抑菌物质的工艺条件。实验结果表明,提取物对大肠杆菌、黑曲霉、金黄色葡萄球菌具有明显的抑制作用,对桔青霉则无抑制作用。对大肠杆菌和黑曲霉的抑菌效果最佳的提取工艺条件为：料液比1∶30,丙酮浓度75%,提取时间40 min,提取温度70℃。对金黄色葡萄球菌最佳的提取工艺条件为：料液比1∶10,丙酮浓度65%,提取时间40 min,提取温度50℃。在优化条件下,菠萝皮的丙酮提取物对大肠杆菌、黑曲霉、金黄色葡萄球菌的MIC分别为60、100、250mg·m L^-1。     

全液压轻便钻机在水利水电工程勘察中的应用

以Explore Jr.36D轻便钻机为例,介绍了轻便钻机的结构特点及性能特性,并探讨了其在工程中的应用情况,并针对钻机稳定性差、钻进能力弱、处理孔故能力弱的问题进行了分析,提出了处理方案,为轻便钻机在水利水电工程勘察中的应用积累了经验。     

港珠澳大桥详勘水文地质条件分析与评价

根据港珠澳大桥经过的水域珠江口—伶仃洋的水文地质条件,沿桥轴线走向采取了多组不同潮水期的海水样及地下水样,进行了水质分析,对水文地质条件和影响水文地质条件的各种因素进行了评价,结果表明:地下水与海水水质类型一致,但阴、阳离子成分及含量不一致,且海水成分随采取时间、地域有不同变化。     

“因形借势”的度假酒店设计——威尼科斯雪野湖度假酒店设计实例

传统度假酒店设计往往受单一模式化制约,在因借地形上尝试不足。笔者所主持设计的威尼科斯雪野湖度假酒店从结合地形入手,组织建筑平面布局,营造富有层次感的建筑形象,同时有效减少了对自然环境的影响。     

LEED铂金建筑解读——以纽约市某游客及管理中心为例

绿色建筑不仅是我国建筑业发展方式的转变,也直接关系着国家的长远利益。但目前,我国绿色建筑发展面临众多问题和挑战。通过对纽约市第一座LEED铂金认证建筑的解读,启示我国绿色建筑设计应因地制宜,同时,也为我国绿色建筑发展提供参考和借鉴。     

海外工程项目“现场异常情况”风险应对研究——基于承包商视角

FIDIC合同条件是海外工程项目中广泛采用的合同范本。针对FIDIC银皮书和红皮书中的"现场数据"条款,分析和研究项目投标和实施过程中因"现场数据"提供的内容和现场实际情况之间的偏差所引发的"现场异常情况"风险,基于承包商的视角,提出规避"现场异常情况"风险的策略,即招投标阶段的项目甄选的策略,投标过程中承包商进行标前现场踏勘的策略,工程实施阶段承包商对"现场异常情况"的防范措施等。     

水文自动测报技术在城市防汛中的应用分析

在城市防汛中应用水文自动测报技术,可全面收集防汛数据信息,进行高效的处理,分析可行性的决策,从而全面发布决策信息等。信息接收处理中心和监测站是水文自动测报系统的重要组成部分,全方位监测各个监测站点。相关部门通过采取水文监测系统,可实现规范的防洪信息处理方式,切实提高城市防汛能力。     

The geodesic dynamic relaxation method for problems of equilibrium with equality constraint conditions

This paper presents an extension to the existing dynamic relaxation method to include equality constraint conditions in the process. The existing dynamic relaxation method is presented as a general, gradient‐based, minimization technique. This representation allows for the introduction of the projected gradient, discrete parallel transportation and pull back operators that enable the formulation of the geodesic dynamic relaxation method, a method that accounts for equality constraint conditions. The characteristics of both the existing and geodesic dynamic relaxation methods are discussed in terms of the system's conservation of energy, damping (viscous, kinetic, and drift), and geometry generation. Particular attention is drawn to the introduction of a novel damping approach named drift damping. This technique is essentially a combination of viscous and kinetic damping. It allows for a smooth and fast convergence rate in both the existing and geodesic dynamic relaxation processes. The case study was performed on the form‐finding of an iconic, ridge‐and‐valley, pre‐stressed membrane system, which is supported by masts. The study shows the potential of the proposed method to account for specified (total) length requirements. The geodesic dynamic relaxation technique is widely applicable to the form‐finding of force‐modeled systems (including mechanically and pressurized pre‐stressed membranes) where equality constraint control is desired. Copyright © 2014 John Wiley & Sons, Ltd.     

一种新型热湿独立控制系统冬季工况下的实验研究

热湿独立控制系统对显热和潜热负荷分开独立处理和控制,通常比传统热泵空调系统高效节能。在冬季工况下对一种新型的湿负荷处理系统(DESICA)以及其与VRV组合构成的热湿独立控制系统进行了实验测试,并将实验结果与传统全热交换器(HRV)和VRV构成的复合系统进行比较研究。研究结果表明:与传统HRVVRV复合系统相比,DESICAVRV复合系统能提供更舒适的室内环境(室温21℃左右,相对湿度50%左右);同时,DESICAVRV系统的能耗降低9%。     

Defect features and mechanical properties of friction stir lap welded dissimilar AA2024–AA7075 aluminum alloy sheets

5 mm-Thick dissimilar AA2024-T3 and AA7075-T6 aluminum alloy sheets were friction stir lap welded in two joint combinations, i.e., (top) 2024/7075 (bottom) and 7075/2024. The influences of process conditions (welding speed and joint combination) on defects (hook and voids) features and mechanical properties of joints were investigated in detail. It was found that the hook deflects largely upwards into the stir zone (SZ) at lower welding speeds (50, 150 mm/min) in both combinations. The process conditions significantly affect the hook geometry which in return affects the lap shear strength. In all 2024/7075 joints, voids appear and the joints fracture from the tip of hook on AS along the SZ/TMAZ (thermomechanically affected zone) interface in lap shear test (tensile fracture mode). In 7075/2024 joints, the hook on RS horizontally extends a large distance into the bottom stir zone at higher welding speeds (225, 300 mm/min). The joints fracture in three modes: shear fracture along the lap interfaces, tensile fracture and the mix fracture of both. In both joint combinations, the lap shear strength generally increases with the increase of welding speed. 7075/2024 Joints show higher failure load than 2024/7075 joints at lower welding speeds while the opposite result appears at higher welding speeds.