烷烃在ZSM-5分子筛上吸附扩散的气相色谱研究

利用气相色谱法测定了不同色谱柱温度和不同载气流速下,C1~12烷烃在ZSM-5分子筛上的保留时间,并利用相关公式对测试结果进行了线性回归分析,测得了吸附热力学参数和扩散系数;考察了色谱柱温度、烷烃碳链长度和载气流速对烷烃在ZSM-5分子筛上吸附扩散的影响。实验结果表明,回归分析的线性相关性良好,色谱柱温度越高,孔道对吸附质的吸附能力越弱;在不同载气流速下,轴向扩散系数不同;随烷烃碳链长度的增加,吸附焓变呈先增大后减小的趋势,轴向扩散系数呈线性增长;C1~12烷烃在ZSM-5分子筛上的吸附焓变在-1.264~-42.975 k J/mol之间;当载气流速为2.654~4.246 cm/s时,C1~4烷烃的轴向扩散系数在0.328 8~0.551 7 cm2/s之间;当载气流速为5.308~13.270 cm/s时,C1~4烷烃的轴向扩散系数在0.430 2~1.456 4 cm2/s之间。     

蚌埠市生活垃圾填埋场工程地质勘察

蚌埠市生活垃圾填埋场工程是城市基础设施,该工程规模大,位于平山半山坡上,工程区地质条件复杂,工作难度大,防渗设计要求严苛.本勘察项目采用钻探、原位取土试样、标准贯入试验、单孔法波速测试试验、室内土工试验、岩石饱和单轴抗压强度试验、水质分析等综合手段勘察,取得了科学准确的参数.本文对填埋场的地基持力层的选择、设计参数、防渗处理等提出了经济合理的结论和建议,为优化设计、节省投资、安全施工奠定了基础.     

基于以太网通讯的生产线信息自动化设计

实际生产中,中小型自动化生产线很少携带生产过程信息.为解决生产过程信息实时掌握困难、可视化程度低等问题,提出了一种基于以太网通讯的中小型自动化生产线生产过程信息自动化的设计.使用西门子CP343-1模块的以太网通讯功能和C#进行信息交互,依靠PLC强大的逻辑功能及信息处理能力,对物料信息进行跟踪记忆,实现生产信息自动获取、自动传输.应用结果表明了该方法的有效性.     

基于速度最优的码垛机器人轨迹规划算法

机器人运行轨迹直接影响其运动效率.在码垛工艺要求下,为追求最快的速度和最优的运行轨迹,提出了一种基于速度最优的机器人运行轨迹规划算法.通过设定机器人运行起始点、目标点,自动对运行轨迹进行规划并计算出所经过的中间点.仿真和实际应用结果表明,所提出的算法减少了码垛工艺下机器人的示教点,并且所规划的路径运行时间较短,提高了生产效率.     

人工挖孔灌注桩后注浆技术的设计应用

本文结合中国中材国际工程股份有限公司总承包工程,通过对扩底人工挖孔灌注桩和采用后注浆技术的人工挖孔灌注桩的比对,说明设计采用灌注桩后注浆技术虽然增加了桩的数量,但明显减少了混凝土和钢筋的总体使用量,从而降低了工程成本。     

Synthesis and Evaluation of Glycoconjugates Comprising N‐Acyl‐Modified Thomsen–Friedenreich Antigens as Anticancer Vaccines

Thomsen–Friedenreich (TF) antigen is an important tumor‐associated carbohydrate antigen. Its low immunogenicity, however, limits its application in the development of anticancer vaccines. To solve this problem, several N‐acyl‐modified TF derivatives were synthesized and conjugated with carrier protein CRM197 (a mutated diphtheria toxoid cross‐reactive material). The immunological results in BALB/c mice demonstrated that these modified TF antigen conjugates could stimulate the production of higher titers of IgG antibodies that cross‐reacted with native TF antigen. These glycoconjugates showed strong lymphocyte proliferative response, suggesting that they can induce cellular immunity. Furthermore, the elicited antisera reacted strongly with TF‐positive tumor cells (4T1). In particular, the N‐monofluoroacetyl‐modified TF conjugate 4 ‐CRM197 showed the strongest complement‐dependent cytotoxicity effect against 4T1 cells, implying the potential of this glycoconjugate as an anticancer vaccine.     

夹杂物对F92/F22异种钢焊接接头冲击性能的影响

采用夏比摆锤冲击试验对同种焊接及焊后热处理工艺条件下的F92/F22异种钢焊接接头焊缝冲击性能进行了研究。结果显示,1号试样的冲击吸收能量(63 J)不足相同工艺条件下2号试样冲击能量(130 J)的1/2。通过扫描电子显微镜(SEM)和能谱(EDS)分析了冲击断口的形貌特征和微区成分,发现在1号试样冲击断口的裂纹形成区存在大小约25μm的复合氧化物夹杂。采用有效投影面积模型计算引发裂纹萌生的临界夹杂物尺寸,分析了夹杂物对F92/F22异种钢焊接接头冲击性能的影响,并确定了该夹杂是造成1号试样冲击吸收能量显著下降的主要原因。因此,应采取适当的工艺措施减少其内部的缺陷,以提高该异种钢焊接接头的冲击性能。     

High porosity glass foams from waste glass and compound blowing agent

The foaming behavior of waste glass green spheres mixed with carbonate was investigated at the temperatures of 680–800 °C. Effects of carbonate on the foaming process, microstructures and properties of the obtained glass foams were evaluated. Both the organic compounds and carbonate act as blowing agents during the foaming process. The results show that the carbonate effectively promotes the foaming process in the temperature range of 680–800 °C. The obtained glass foams show uniform microstructure, with bulk density, porosity and compressive strength values of 0.117–0.209 g/cm³, 91.7–95.4 % and 0.52–3.93 MPa, respectively. The high porosity glass foams have potential applications in many areas such as thermal insulation materials and sound absorption materials.     

Structure and Substrate Recognition of the Bottromycin Maturation Enzyme BotP

The bottromycins are a family of highly modified peptide natural products, which display potent antimicrobial activity against Gram‐positive bacteria, including methicillin‐resistant Staphylococcus aureus. Bottromycins have recently been shown to be ribosomally synthesized and post‐translationally modified peptides (RiPPs). Unique amongst RiPPs, the precursor peptide BotA contains a C‐terminal “follower” sequence, rather than the canonical N‐terminal “leader” sequence. We report herein the structural and biochemical characterization of BotP, a leucyl‐aminopeptidase‐like enzyme from the bottromycin pathway. We demonstrate that BotP is responsible for the removal of the N‐terminal methionine from the precursor peptide. Determining the crystal structures of both apo BotP and BotP in complex with Mn²⁺ allowed us to model a BotP/substrate complex and to rationalize substrate recognition. Our data represent the first step towards targeted compound modification to unlock the full antibiotic potential of bottro‐ mycin.     

Cu 含量对Ti-Cu合金半固态可锻性及锻造后力学性能的影响

通过镦锻试验和模锻实验研究了Ti-Cu系合金半固态锻造行为,并对锻材进行了拉伸试验,讨论了Cu含量对半固态可锻性及力学性能的影响。结果表明：1000 °C至1150°C半固态锻造较常规锻造具有较小的顶锻压力;其中,1000 °C至1050°C间半固态锻造的Ti-Cu系合金均表现出较好的可锻性,在75%的锻造变形量下无明显缺陷。分析认为,Ti-Cu系列合金中含有较多的低熔点Ti2Cu相,随着半固态温度升高或Cu含量的增加,材料中的液相含量增加,增加的液相含量对变形起到润滑作用,减少了固相变形引起的应力集中,有效的降低了变形抗力,改善了成形性。力学性能研究表明：半固态锻造Ti-Cu系合金较常规锻造合金强度升高,塑性降低。随着Cu含量的升高,合金的强度明显提升,塑性降低。分析认为：力学性能的变化主要是由于Ti2Cu相析出含量、形态和分布相关,随着Cu含量和半固态温度的升高,更多Ti2Cu相在晶内和晶界析出,引起析出强化作用,同时,晶界析出的针状Ti2Cu相形成了偏析带,降低了合金塑形。