张家口市“首都两区”建设中的水资源考量

张家口市属于严重缺水地区,近年来受气候变化以及水资源不合理开发利用等多重因素叠加影响,水资源量持续减少,地下水超采、地表水和地下水污染等水资源问题仍然存在。"首都两区"建设应充分考虑张家口市水资源空间分布的差异性,把水资源作为前置刚性约束条件,统筹好张家口市自身发展用水和"首都两区"用水问题。在水资源相对丰富且能直接对首都供水的坝下地区以水源涵养区建设为主;在水资源匮乏、自然环境脆弱、不能直接向首都供水的坝上地区以生态支撑区建设为主。坝上首都生态支撑区建设中人工植被的选择与配置要充分考虑地区水资源条件,人工植被恢复时应慎重选择乔木和灌木,优先选择草本植物。     

核电压力容器SA508-3钢内部裂纹高温焊合实验

裂纹缺陷严重影响大型锻件的合格率及使用寿命。为保证核电大型锻件质量、提高核电压力容器安全性,以加热温度、下压量以及保压时间为参数,采用预置裂纹方式对核电压力容器用钢SA508-3进行内部裂纹高温焊合实验研究。裂纹焊合效果采用金相显微镜、扫描电镜、能谱分析及力学性能实验等进行评价。结果显示,在高温短时间小变形情况下SA508-3材料内部裂纹均能焊合,裂纹焊合最低条件为:加热温度1100℃,变形量10%,保压时间15 s;焊合后试样强度值与基体相似,但塑性值有较大波动;根据扫描电镜及能谱分析确定,试样连接过程中带入的大量夹杂物是材料塑性指标波动较大的主要原因。     

Finite-element vibration analysis of tapping-mode atomic force microscopy in liquid

Investigation of morphology and mechanical properties of biological specimens using atomic force microscopy (AFM) often requires its operation in liquid environment. Due to the hydrodynamic force, the vibration of AFM cantilevers in liquid shows dramatically different dynamic characteristics from that in air. A good understanding of the dynamics of AFM cantilevers vibrating in liquid is needed for the interpretation of scanning images, selection of AFM operating conditions, and evaluation of sample's mechanical properties. In this study, a finite element (FE) model is used for frequency and transient response analysis of AFM cantilevers in tapping mode (TM) operated in air or liquid. Hydrodynamic force exerted by the fluid on AFM cantilevers is approximated by additional mass and hydrodynamic damping. The additional mass and hydrodynamic damping matrices corresponding to beam elements are derived. With this model, numerical simulations are performed for an AFM cantilever to obtain the frequency and transient responses of the cantilever in air and liquid. The comparison between our simulated results and the experimentally obtained ones shows good agreement. Based on the simulations, different characteristics of cantilever dynamics in air and liquid are discussed.     

浅淡技术情报在企业技术创新中的重要性

介绍技术情报在企业技术创新中的重要性和支撑作用,提出了两种创新模式中技术情报收集应注意的问题。     

全自动洗衣机的PLC控制

利用日本松下公司生产的微型Pe-1型PLC,设计出PLC控制的全自动洗衣机。可编程控制器（PLC,Program-mable Logic Controller）是以计算机微处理器为基础的工业自动控制装置,随着PLC技术的发展,它的功能越来越完善,也越来越强,被广泛应用于各种工业自动控制装置之中,PLC集三电一体,具有良好的控制精度和可靠性。PLC的生产厂家、型号、种类繁多,不同型号有不同的使用方法和编程语言。本文拟用日本松下公司生产的Pe-1微型PLC,设计出PLC在全自动洗衣机控制中的应用,既可以作为高校学生学习PLC控制的参考,也可以作为有关技术人员维修改造全自动洗衣机控制电路的参考。     

Discovery of SARS-CoV-2 3CLPro Peptidomimetic Inhibitors through the Catalytic Dyad Histidine-Specific Protein–Ligand Interactions

As the etiological agent for the coronavirus disease 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) challenges the ongoing efforts of vaccine development and drug design. Due to the accumulating cases of breakthrough infections, there are urgent needs for broad-spectrum antiviral medicines. Here, we designed and examined five new tetrapeptidomimetic anti-SARS-CoV-2 inhibitors targeting the 3C-Like protease (3CL^Pro), which is highly conserved among coronaviruses and essential for viral replications. We significantly improved the efficacy of a ketoamide lead compound based on high-resolution co-crystal structures, all-atom simulations, and binding energy calculations. The inhibitors successfully engaged the catalytic dyad histidine residue (H41) of 3CLPro as designed, and they exhibited nanomolar inhibitory capacity as well as mitigated the viral loads of SARS-CoV-2 in cellular assays. As a widely applicable design principle, our results revealed that the potencies of 3CL^Pro-specific drug candidates were determined by the interplay between 3CL^Pro H41 residue and the peptidomimetic inhibitors.     

基于响应面法的碳酸钠活化铜尾矿胶凝性能机制研究

为了有效激发铜尾矿活性制备性能良好的胶凝材料,以铜尾矿为主要原材料,水玻璃和NaOH为碱激发剂,采用响应面优化法开展胶凝材料配比优化实验,并通过方差分析以及三维曲图研究自变量及其交互作用对28d抗压强度的影响;利用XRD、SEM、FT-IR、TG-DTG等对试样的矿相成分、微观形貌等特征进行分析。结果表明：通过优化实验获得最优配比为碳酸钠掺量50%、氢氧化钠掺量1%、水玻璃掺量22g/100g,此参数下铜尾矿胶凝材料28d抗压强度为30.41MPa。经过机械球磨40min后,碳酸钠在适当的碱性环境下使铜尾矿的活性激发到较佳状态,铜尾矿经水化反应生成了大量结晶度较高的C-S-H凝胶与棱柱状钙钒石等水化产物,彼此相互连接构成网状结构,使胶凝材料保持较高的强度性能。     

玻璃钢/钢复合结构带式舟桥方舟的制作工艺

根据玻璃钢和钢材这两种材料的优点及现行带式舟桥的结构特点,论述了采用玻璃钢/钢复合结构研制新型带式舟桥的构想。以带式舟桥方舟模型的制作为例,提出了实现上述构想的工艺设计方案,并详细阐述了以手糊成型为主的制作工艺。研究结果表明,玻璃钢/钢复合结构带式舟桥的制作工艺方便、可行,经试验验证,结果可靠,对促进玻璃钢在舟桥器材中的应用具有指导意义。     

加工高含硫原油设备管道腐蚀及相应措施

安庆炼油厂从 2 0 0 1年起由于加工胜利原油的比例增加 ,致使加工原油的平均硫含量达到 0 .81% ,平均酸值达到 0 .84mgKOH/g ,设备管道腐蚀严重。其中低温部位主要表现为H2 S -HCl-H2 O腐蚀 ;二次加工装置 (如焦化 )主要表现为高温硫腐蚀。在加强“一脱三注”的情况下 ,选用钛材、0 9Cr2AlMoRe、Ni-P镀等耐蚀材料以及采取涂料 -电化学保护措施可使腐蚀得到控制