超级风冷二冲程汽油机油的排烟性能

利用烟度模拟试验，热管氧化试验，板式成焦器详细考察了聚异丁烯加入量，聚异丁烯分子量，加氢聚异丁烯和非加氢聚异丁烯与油品排烟性能，清净性能的关系，使用高低分子量聚异丁烯复合成功研制出了满足ＪＡＳＯＭ３４５规格要求的低烟型超级风冷二冲程汽油机油。     

小型二冲程汽油机气口主要参数的计算和确定

本文以气口的比时面值为中心 ,系统地介绍了化油器式曲轴箱回流扫气小型二冲程汽油机对称配气正时气口各个主要参数的计算和确定问题。首先介绍了所需要的气口比时面值的计算和确定方法 ,其中对最早由A·C·奥尔林提出 ,现被我国内燃机教科书和设计手册采用 ,由气体流量方程式推导出的计算公式进行了修正 ,使其计算结果与现有小型二冲程汽油机的现实数据相一致。随后介绍了一种已知结构和运转参数 ,计算比时面值的新方法———系数计算法。最后介绍了由给定比时面值计算其所需气口配气相位角和气口高度的方法 ,填补了这方面的空白     

塔架式长冲程抽油机原理及应用

塔架式长冲程抽油机(20～22型)是配合油田采用新工艺而研制开发的.在给出其工作原理的基础上,进行了运动规律分析;阐述了基本技术参数和相关操作功能.该机具有长冲程、软性换向、对称对拉、高度平衡、高效节能、大载荷等特点,经过辽河油田试用,效果良好.     

NUMERICAL SIMULATION OF ROCK BREAKING MECHANISM WITH HIGH-PRESSURE WATER JET

Based on the analysis of experimental results.the rock damage model and the damage coupling model suitable for the whole rock breaking process with water jet were established with continuous damage mechanics and micro damage mechanics, and the numerical method was developed with continuum mechanics and the FEM theory. The rock breaking mechanism with water jet was studied systematically with numerical simulation for the first time in the field of water-jet rock breaking. The numerical results agree with the experimental ones which shows that the presented method is reasonable and can reflect the reality of water-jet rock breaking. The conclusion can be applied in practice.     

HPLC-Q-TOF MS鉴定条叶榕根茎乙酸乙酯提取物中的主要化学成分

采用高效液相色谱-四极杆飞行时间质谱(HPLC-Q-TOF MS)技术对条叶榕根茎乙酸乙酯提取物中的多种活性化学组分进行了分析鉴定。采用正离子与负离子两种扫描方式,依据高分辨质谱提供的准分子离子峰和碎片离子的精确分子质量信息,确证了有关物质及其特征碎片离子的分子组成。再结合标准品对照与相关文献数据支持,最终鉴定出条叶榕根茎乙酸乙酯提取物中的34种化学成分,其中包括12种多酚、8种香豆素、9种黄酮、4种脂肪酸、1种蒽醌。结果表明,采用HPLC-Q-TOF MS技术可提高中药化学成分的分析效率,有利于新化合物的发现与鉴别。     

基于BP 神经网络的破片聚焦曲线优化

为解决战斗部预制破片的飞散方向控制这个复杂的非线性问题,基于大量试验和仿真数据,应用BP 神经 网络技术对破片飞散方向修正设计量进行预测,建立破片聚焦曲线优化设计系统,可对传统解析模型设计的破片聚 焦曲线进行自动优化。试验结果表明：优化后的聚焦曲线具有较高的破片聚焦效率,可有效减少破片聚焦曲线迭代 的试验次数。     

某杀爆战斗部破片与冲击波运动规律研究

通过对某杀爆战斗部爆炸后破片运动及冲击波传播的研究,理论推导了破片与冲击波相遇位置的求解全过程。采用Visual C++开发破片与冲击波运动规律计算系统,并用数值积分方法对冲击波速度与位移进行分段积分。通过该系统计算了某预制破片战斗部破片与冲击波的相遇位置,并运用 ANSYS/LS-DYN数值模拟了该预制破片战斗部爆炸后破片与冲击波的运动,数值模拟结果与计算结果基本相符。     

大偏心量重载的组合式曲轴及其弹性支撑方式的探讨

本文对曲轴的四种弹性支撑方式进行了有限元分析,得到了支撑轴套分别采用四种不同支撑材料的曲轴及弹性支撑的最大应力和应变。以630 k N曲柄压力机所使用的曲轴为例,采用Pro/e软件设计并建立了整体式曲轴、组装式曲轴和部分组装式曲轴在刚性支撑时的三维模型。采用ANSYS软件分别对三种曲轴结构进行了有限元分析,得到了三种曲轴结构的最大应力和应变。从制造工艺、与连杆装配、最大应力和应变等方面对三种曲轴进行了分析对比,为以后曲轴的设计提供参考依据。     

One Question,Multiple Answers: Biochemical and Biophysical Screening Methods Retrieve Deviating Fragment Hit Lists

Fragment‐based lead discovery is gaining momentum in drug development. Typically, a hierarchical cascade of several screening techniques is consulted to identify fragment hits which are then analyzed by crystallography. Because crystal structures with bound fragments are essential for the subsequent hit‐to‐lead‐to‐drug optimization, the screening process should distinguish reliably between binders and non‐binders. We therefore investigated whether different screening methods would reveal similar collections of putative binders. First we used a biochemical assay to identify fragments that bind to endothiapepsin, a surrogate for disease‐relevant aspartic proteases. In a comprehensive screening approach, we then evaluated our 361‐entry library by using a reporter‐displacement assay, saturation‐transfer difference NMR, native mass spectrometry, thermophoresis, and a thermal shift assay. While the combined results of these screening methods retrieve 10 of the 11 crystal structures originally predicted by the biochemical assay, the mutual overlap of individual hit lists is surprisingly low, highlighting that each technique operates on different biophysical principles and conditions.     

Merging Allosteric and Active Site Binding Motifs: De novo Generation of Target Selectivity and Potency via Natural‐Product‐Derived Fragments

The de novo design of molecules from scratch with tailored biological activity is still the major intellectual challenge in chemical biology and drug discovery. Herein we validate natural‐product‐derived fragments (NPDFs) as excellent molecular seeds for the targeted de novo discovery of lead structures for the modulation of therapeutically relevant proteins. The application of this de novo approach delivered, in synergy with the combination of allosteric and active site binding motifs, highly selective and ligand‐efficient non‐zinc‐binding ( 3 : 4‐{[5‐(2‐{[(3‐methoxyphenyl)methyl]carbamoyl}eth‐1‐yn‐1‐yl)‐2,4‐dioxo‐1,2,3,4‐tetrahydropyrimidin‐1‐yl]methyl}benzoic acid) as well as zinc‐binding ( 4 : 4‐({5‐[2‐({[3‐(3‐carboxypropoxy)phenyl]methyl}carbamoyl)eth‐1‐yn‐1‐yl]‐2,4‐dioxo‐1,2,3,4‐tetrahydropyrimidin‐1‐yl}methyl)benzoic acid) uracil‐based MMP‐13 inhibitors presenting IC₅₀ values of 11 nM ( 3 : LE=0.35) and 6 nM ( 4 : LE=0.31).