用异丙醇精制胆固醇

选用异丙醇分别重结晶熔点140℃和147℃的胆固醇,优化了所用异丙醇的最佳质量分数为75%,重结晶时胆固醇溶解完全,单步收率达到92.0%,所得产品指标分别达到147℃胆固醇和液晶用胆固醇的质量要求,并将异丙醇和其他常用胆固醇精制方法作了比较。     

正火预处理对高速犁用28MnB5钢组织及力学性能的影响

为解决现有国产高速犁入土部件存在强韧性不足的问题,研究了正火-淬火-回火(N-Q-T)工艺对28MnB5钢微观组织与力学性能的影响机制,并与现有淬火-回火(Q-T)工艺生产的高速犁入土部件进行了对比。结果表明,N-Q-T态和Q-T态28MnB5钢的组织均以板条马氏体为主,N-Q-T态的马氏体板条平均宽度(0.9μm)显著低于Q-T态(1.5μm),且N-Q-T态的强度和韧性均显著高于Q-T态。基于Hall-Petch关系进一步分析可知,板条马氏体细化是导致N-Q-T态28MnB5钢强度提升的主要原因。同时,N-Q-T态28MnB5钢的板条马氏体细化也导致其大角度晶界占比(34.9%)显著高于Q-T态(25.1%),有助于产生更多的残留奥氏体来抑制裂纹的扩展,从而间接地提高韧性。     

多策略改进型麻雀算法在水下伸缩臂轨迹定位的应用

针对深层水域水下机器人通过机械臂捕捉目标物定位精度低、搜索难度大、耗费时间长的问题,提出一种基于多策略改进型麻雀搜索算法的水下机器人伸缩臂轨迹定位方法。通过D-H参数法搭建伸缩臂模型,结合MATLAB和ADAMS分析伸缩臂在水下捕捉目标物群目标物的低效性,引用麻雀搜索算法中鸟群觅食在最优位置的思想,引入Logistic混沌映射和柯西高斯变异原理,通过水下机器人的4项性能指标分析最优结果。结果表明：优化后的麻雀算法优于其他算法,同粒子群算法、天牛群算法、鲸鱼优化算法相比,伸缩臂捕捉目标物轨迹路线更加精确,水域环境下避障更为明显。     

动态场景下移动机器人视觉SLAM

为实现动态场景下移动机器人自主定位和建图,解决传统视觉里程计方法跟踪效果差及累积误差问题,提升闭环检测的准确性和鲁棒性,提出融合深度学习的同时定位与地图构建方法。采用四叉树算法均匀化特征分布,解决动态场景特征聚集问题;通过优化的目标检测网络识别场景动态语义信息,剔除动态物体对位姿估计的干扰;充分提取场景空间结构信息,结合点特征和线特征实现位姿跟踪及回环检测,构建全局一致的环境地图。TUM数据集和真实场景实验结果表明：改进方法提升了移动机器人定位和建图的准确性和鲁棒性。     

道次压下量对2197铝锂合金轧制组织与力学性能的影响

针对铝锂合金塑韧性、成形性差的问题,本工作通过OM/SEM微观组织分析、拉伸及硬度/电导率测试,研究了在总压下量75%条件下、轧制道次压下量(即10%、30%、30%+60%,分别对应小、中、大道次压下量)对2197铝锂合金组织与力学性能的影响。结果表明：道次压下量显著影响铝锂合金的晶粒结构、析出相的数量及分布。轧制态合金的强度随单道次轧制压下量的增加而显著增加、而塑韧性则明显下降。T8时效处理使析出相大量析出,轧制合金中的Portevin-Le Chatelier(PLC)效应得到消除,小、大道次压下量轧制合金的力学性能得到显著提升。大压下量轧制合金经时效处理后强塑性综合力学性能最高,抗拉强度为384.94 MPa、断后伸长率为12.45%,较小、中道次压下量轧制时效合金分别提高2%、21%和29%、31%。     

复合挤压对Mg-4Sn-2Al-1Zn合金组织及力学性能的影响

针对镁合金室温强度低、塑性差的问题,采用复合挤压工艺在250℃对Mg-4Sn-2Al-1Zn合金进行了挤压,研究了复合挤压对合金的组织演变、织构及力学性能的影响。结果表明,复合挤压能将Mg-4Sn-2Al-1Zn合金的晶粒尺寸由45.2μm细化至3.1μm,组织均匀。挤压后的合金硬度提升,均匀性改善,屈服强度、抗拉强度和断后伸长率分别为204 MPa、287 MPa和21.0%,较匀质态分别提高了140.0%、91.3%和156.1%。动态再结晶是晶粒细化的主要机制,晶粒细化以及挤压后基面织构增强、织构向挤压方向均匀扩展使合金强度、塑性提高,挤压过程中Mg2Sn相破碎进一步提高了合金的力学性能。上述研究表明复合挤压是一种能有效提高镁合金综合性能的工艺。     

超声喷丸对工业纯Zr疲劳裂纹扩展行为的影响

对厚度为2.0 mm的工业纯锆板材进行双面超声喷丸（USSP）处理,研究了超声喷丸（USSP）对微观组织演变和疲劳裂纹扩展（FCG）行为的影响。通过光学显微镜、激光共聚焦显微镜、背散射电子衍射仪、透射电子显微镜和X射线衍射仪分别对微观结构演变进行表征。采用紧凑拉伸试样进行FCG试验,对断口形貌和裂纹扩展路径进行分析。结果表明,USSP处理后形成了具有约250 μm深度残余压应力的表面梯度结构,USSP试样比原始试样表现出更高的强度和表面粗糙度。值得注意的是,USSP-8 min和USSP-12 min试样的疲劳裂纹扩展寿命比原始试样分别提高了28.1%和50.9%。USSP处理有助于提高疲劳裂纹扩展抗力,进而在一定程度上降低疲劳裂纹的扩展速率。FCG性能的提高可归因于残余压应力和晶粒细化的共同作用,残余压应力增强了裂纹闭合效应,降低了有效应力比。同时,晶粒细化使晶界比例增加,循环塑性区尺寸减小,从而有利于抵抗裂纹扩展。     

TDI双管板换热器制造质量的控制简

介绍了TDI双管板换热器的结构特点和深孔强度胀接技术。简述了制造过程中的质量控制关键点。通过用模拟管板进行了内管板胀接工艺评定的方法,采取了控制管孔加工精度、强度胀接、管板组装、调整开槽间距及宽度、安排合理的胀接焊接次序、选择合适的胀接压力等措施;采用了新的检验和检测技术,保证了产品质量;增设了压力传感器,完善了安全监测系统。     

Design of a General‐Purpose European Compound Screening Library for EU‐OPENSCREEN

This work describes a collaborative effort to define and apply a protocol for the rational selection of a general‐purpose screening library, to be used by the screening platforms affiliated with the EU‐OPENSCREEN initiative. It is designed as a standard source of compounds for primary screening against novel biological targets, at the request of research partners. Given the general nature of the potential applications of this compound collection, the focus of the selection strategy lies on ensuring chemical stability, absence of reactive compounds, screening‐compliant physicochemical properties, loose compliance to drug‐likeness criteria (as drug design is a major, but not exclusive application), and maximal diversity/coverage of chemical space, aimed at providing hits for a wide spectrum of drugable targets. Finally, practical availability/cost issues cannot be avoided. The main goal of this publication is to inform potential future users of this library about its conception, sources, and characteristics. The outline of the selection procedure, notably of the filtering rules designed by a large committee of European medicinal chemists and chemoinformaticians, may be of general methodological interest for the screening/medicinal chemistry community. The selection task of 200K molecules out of a pre‐filtered set of 1.4M candidates was shared by five independent European research groups, each picking a subset of 40K compounds according to their own in‐house methodology and expertise. An in‐depth analysis of chemical space coverage of the library serves not only to characterize the collection, but also to compare the various chemoinformatics‐driven selection procedures of maximal diversity sets. Compound selections contributed by various participating groups were mapped onto general‐purpose self‐organizing maps (SOMs) built on the basis of marketed drugs and bioactive reference molecules. In this way, the occupancy of chemical space by the EU‐OPENSCREEN library could be directly compared with distributions of known bioactives of various classes. This mapping highlights the relevance of the selection and shows how the consensus reached by merging the five different 40K selections contributes to achieve this relevance. The approach also allows one to readily identify subsets of target‐ or target‐class‐oriented compounds from the EU‐OPENSCREEN library to suit the needs of the diverse range of potential users. The final EU‐OPENSCREEN library, assembled by merging five independent selections of 40K compounds from various expert groups, represents an excellent example of a Europe‐wide collaborative effort toward the common objective of building best‐in‐class European open screening platforms.     

大比例尺数字测图的发展趋势

介绍了数字测图的产生背景,并对测量方法与手段的发展历程进行了阐述,分析了大比例尺数字测图系统的发展与简化,最后对大比例尺数字测图的发展趋势进行了展望,以减轻工作人员的工作强度,同时提高了测图的精度。