基于脉冲微孔喷射的液滴沉积成型

基于脉冲微孔喷射法(POEM)开发均匀液滴喷射成型设备,可实现均匀微熔滴的逐滴三维沉积,并通过一系列实验研究一维柱沉积时微熔滴沉积位置的准确性以及一维线沉积时平台运动速率对微熔滴结合的影响。结果表明:微熔滴的沉积具有可重复性并且沉积位置准确;当平台运动速率为600μm/s时,微熔滴间的结合良好,表面光滑无明显缺陷。最后进行简单立体薄壁制件的沉积,制件结构稳定,熔滴排布均匀,因此该方法可实现金属均匀微滴的沉积成型。     

Dijkstra Algorithm and the Application of theOptimal Path in the GIS System

If there is no timely,accurate fire and rescue when toxic and harmful substances leak,which will seriously threaten the safety of enterprises and people.Based on the fire and rescue after toxic and hazardous substances leaking,this paper optimizes the classical Dijkstra algorithm from the two aspects of algorithm and memory structure,and the optimized algorithm is applied to GIS for the best path.The final results show that using the optimized algorithm in the GIS can facilitate the workers to avrive at the scene of accident quickly and accurately and impement emergency fire and rescue measures.     

基于有限元的救生舱生存舱结构分析

采用有限元的方案来对矿用救生舱的生存舱壳体的2种工况进行受力分析和研究,通过分析和研究得出在三面受力和单侧受力作用下,均有相当数量的骨架杆件进入塑性区域,单侧受力作用下,塑性变形区域有所缩小。     

The devolution of urban food waste governance: Case study of food rescue in Los Angeles

In Los Angeles (LA), food waste is at record levels. This has negative outcomes for food insecurity, land use, and methane production associated with climate change. To overcome these challenges, a range of government, private, and civil society organizations (CSOs) have developed programs to reduce food waste. With the decentralization, privatization, and devolution of food waste policies to local actors, CSOs have emerged as key institutions in the governance of food waste in many contexts. However, it is unclear whether CSOs have the capacity to reduce food waste and food insecurity, empower communities, or promote social change. To this end, this paper critically analyzes a local food rescue CSO as a case study in order to understand the challenges associated with food waste governance in LA and the roles that CSOs play in food waste reduction. Through an analysis of interview and participant observation data in LA’s food system, this paper examines the ways that food waste is produced, regulated, and reused by institutions in LA. Findings illustrate that although local CSOs have expanded their food waste reduction programs, the impact of their operations may be limited. In addition, while CSOs rescue some food, they operate in conjunction with food waste surpluses and the overabundance of food, and do little to reduce the root cause of food waste or food insecurity. Although the structural causes of food waste are arguably beyond the scope of some CSOs to change, data in this paper suggest that some CSOs may contribute indirectly to neoliberal governance when they romanticize the power of local communities, depoliticize food issues, and focus on individual personal responsibility. For these reasons, this research suggests that food waste may only be reduced significantly with more government regulation of the institutions which produce food waste, namely food businesses and households.     

从硫脲热解谈消防部队处置化学事故的若干问题

从硫脲热解化学事故处置的实例出发,分析该类事故的特点,并结合联动反应、侦检疏散、稀释沉降、通风洗消等处置要点,从技战术的软件和装备器材运用的硬件两方面提出了救人第一、迅速有效的联动和保障、科学调度指挥、严格执行程序等9个方面的思考,为今后处置类似的化学事故提供参考。     

旋挖钻机在平邑石膏矿坍塌事故大直径救生孔钻进中的应用

2015年12月25日,山东省平邑县一石膏矿发生坍塌事故,多人被埋井下。由于救援人员通往井下的通道被堵死,利用巷道进行救援很难实施。为避免次生事故,决定采用大口径钻机打孔救援方案。救援过程中,多台钻机相互配合,BG26、BG38型旋挖钻机钻进上部孔段,RB-T90、T200XD型多功能钻机钻进下部孔段。钻达最终深度220 m后,成功将被困人员救出,创造了中国矿山救援史上第一个通过地面打孔救援的案例。主要介绍旋挖钻机在大直径救生孔成孔过程中关键技术点的控制,从钻头选择、护筒埋设、成孔钻进方面对钻孔垂直度进行控制;采用下入护筒、熟练人员精心操作、干成孔工艺等避免钻孔坍塌。     

新型推力可控垂直发射装置及其内弹道规律

为提高发射装置的通用性,提出了一种新型“类同心筒”弹射装置——推力可控垂直发射装置。通过零维内弹道计算和三维内弹道仿真两种方法,分析了低压室燃气出口面积对发射装置内弹道性能的影响;通过多项式拟合得到了低压室燃气出口面积与弹射最大加速度、出筒速度、出筒时间的关系式,并对拟合关系式进行了验证;研究结果表明：改变低压室燃气出口面积控制发射装置推力是可行的;导弹出筒时间、出筒速度、最大加速度随低压室燃气出口面积近似线性变化——低压室燃气出口面积减小,导弹最大加速度增大,出筒速度增大,出筒时间减小;拟合关系式的弹射最大加速度误差在8%以内,出筒速度与出筒时间误差在4%以内。     

广州沥滘古村文化遗产保护的若干思考

名城广州海珠区沥滘村是一个历史文化底蕴深厚的古村落,为使众多颇具历代营造特色的古祠寺、古民居,民国别墅建筑及古树名木、河涌水体等文化景观,避免遭遇到卷地毯式的拆迁破坏。本文呼吁纠正当前这种错误性的开发模式,采取抢救文物、恢复生态作为公共绿地、敬畏历史自然的设计手法,制定抽疏保留原有建筑组建新型城（社）区的低碳绿色规划政策,为培育世界名城多做善事。     

套索驱动细长机器人的初步设计与试验

为了解决在地震后废墟内部搜救幸存者的问题,设计了一种细长柔软机器人.机器人采用了套索传动的方式,使机器人操作部分的尺寸和重量相对于其他搜救机器人大大减小.机器人由头部可操作部分和细长柔软身体组成,可运动的操作部分采用模块化的设计,可根据实际需要改变关节的数量.实验结果表明,机器人能初步完成搜救任务.     

关于防护窗逃生功能的研究及解决方案

从当今大多数防护窗防护与逃生功能相矛盾的角度出发,对其进行了调查研究,并设计了一种比较合理的、结合了逃生与防护功能的新型逃生防护窗。