材料力学性能对液力胀接过程的影响分析

为寻求装配式空心凸轮轴结构设计和材料选择的理论依据,应用弹塑性力学分析了弹性模量和流动应力对液力胀接的影响.将内外管的变形过程简化为平面应变问题,根据典型点应力-应变曲线分析了液力胀接过程,并给出了不同材质套管的连接条件.研究结果表明:影响液力胀接的主要因素是内外管弹性模量和流动应力,这两个材料参数决定胀后内外管弹性回复量的大小;实现液力胀接内外管应满足的条件是:内外管弹性模量的比值大于内外管流动应力的比值.     

Binding Properties of RNA Quadruplex of SARS-CoV-2 to Berberine Compared to Telomeric DNA Quadruplex

Previous studies suggest that berberine, an isoquinoline alkaloid, has antiviral potential and is a possible therapeutic candidate against SARS-CoV-2. The molecular underpinnings of its action are still unknown. Potential targets include quadruplexes (G4Q) in the viral genome as they play a key role in modulating the biological activity of viruses. While several DNA-G4Q structures and their binding properties have been elucidated, RNA-G4Qs such as RG-1 of the N-gene of SARS-CoV-2 are less explored. Using biophysical techniques, the berberine binding thermodynamics and the associated conformational and hydration changes of RG-1 could be characterized and compared with human telomeric DNA-G4Q 22AG. Berberine can interact with both quadruplexes. Substantial changes were observed in the interaction of berberine with 22AG and RG-1, which adopt different topologies that can also change upon ligand binding. The strength of interaction and the thermodynamic signatures were found to dependent not only on the initial conformation of the quadruplex, but also on the type of salt present in solution. Since berberine has shown promise as a G-quadruplex stabilizer that can modulate viral gene expression, this study may also contribute to the development of optimized ligands that can discriminate between binding to DNA and RNA G-quadruplexes.     

轴流涡轮与排气壳扩压段一维耦合设计研究

为探究轴流涡轮耦合排气壳扩压段的一维设计变量选取规律,提高排气壳扩压段的性能,参考现有NRCC叶栅导叶模型,采用自编程序,结合理论分析构建轴流涡轮与排气扩压段耦合的一维设计模型。详细分析耦合设计中影响扩压段的静压恢复系数以及总体性能的因素。研究结果表明：扩压段面积比、平均倾角、扩张角以及壁面摩擦系数等设计参数不仅影响扩压段的静压恢复系数,也影响涡轮的气动效率;本研究模型在面积比为3.5、平均倾角为30°、扩张角δ为5°时整体性能最优;涡轮出口气流的马赫数、叶顶泄漏流以及出口旋流对扩压段的性能有很大影响,出口半径比的增大会使得静压恢复系数降低,因此在耦合设计时应充分考虑涡轮以上参数的选择。     

不同地应力下的地下硐室动态特征分析

采用FLAC3D对地震动荷载作用下不同地应力状态的地下岩体硐室的动态特性进行了初步分析。分析结果表明,地震荷载作用下,硐室位移随地应力侧压系数的增加明显减小,地应力侧压系数λ<1时的硐室位移量值随侧压系数的变化幅度明显大于地应力侧压系数λ>1时的情况;当侧压系数λ<1,随剪切波入射角的变化,硐室测量点位移响应先增加后减小;而当侧压系数λ>1,随剪切波入射角的增加,硐室测点位移先减小后增加,同时随地应力侧压系数的增加有减小的趋势。     

液压推移排矸架头的维护及改进

在总结近几年工作的基础上,对液压推移排矸架头的日常维护和保养作了分析总结,着重阐述其在实际应用过程中的不足之处,并有针对性地提出了进行改进的方法和建议,具有较强的实用价值和一定的借鉴意义。     

基于PVDF薄膜的智能材料回声控制实现

提出了用高分子压电材料——PVDF薄膜作为激励声源，将其内嵌于基体材料聚氨酯橡胶中制成具有特殊功能的消声材料。通过声时延的方法，用布置在消声样件前方的两传声器检测出平面入射声波和反射声波，利用压电材料PVDF薄膜的逆压电性能，对其施加具有一定幅值和相位的电压，实现样件材料的声阻抗和介质声阻抗的匹配，以使得反射声波达到最小或零，从而实现回声控制的目的。最后对不同频率的入射声波进行了基于声阻抗管的回声控制实验测试并对结果进行了分析。     

基础振动下直动式减压阀动态特性分析

针对基础振动对TBM液压元件性能的影响,为TBM液压元件优化设计提供理论依据,选择直动式减压阀为研究对象,分析其工作原理,建立减压阀的动态响应数学模型,仿真研究基础振动幅值和频率对减压阀波动特性的影响规律,分析减压阀不同结构参数对压力波动的影响.结果表明：基础振动会引起减压阀出口压力波动,波动幅值随振动幅值增加而增大;当基础振动频率大于50 Hz时,压力波动幅值随频率的增加明显增大;减小背压腔初始容积和回流通道直径能提高减压阀的动态稳定性.     

Creation of Nonspherical Microparticles through Osmosis‐Driven Arrested Coalescence of Microfluidic Emulsions

Droplet‐based microfluidics enable the production of emulsions and microparticles with spherical shapes, but the high‐throughput fabrication of nonspherical emulsions and microparticles still remains challenging because interfacial tension plays a dominant role during preparation. Herein, ionic liquids (ILs) containing salts, which possess sufficient osmotic pressure to realize water transport and phase separation, are introduced as inner cores of oil‐in‐oil‐in‐water double emulsions and it is shown that nonspherical emulsions can be constructed by osmosis‐driven arrested coalescence of inner cores. Subsequently, ultraviolet polymerization of the nonspherical emulsions leads to nonspherical microparticles. By tailoring the number, composition, and size of inner cores as well as coalescence time, a variety of nonspherical shapes such as dumbbell, rod, spindle, snowman, tumbler, three‐pointed star, triangle, and scalene triangle are created. Importantly, benefitting from excellent solvency of ILs, this system can serve as a general platform to produce nonspherical microparticles made from different materials. Moreover, by controlling the osmotic pressure, programmed coalescence of inner cores in double emulsions is realizable, which indicates the potential to build microreactors. Thus, a simple and high‐throughput strategy to create nonspherical microparticles with arrested coalescence shapes is developed for the first time and can be further used to construct novel materials and microreactors.     

MgO－CoO－NiO氧敏材料的缺陷化学及电导特性研究

本文用点缺陷理论分析了ＭｇＯ－ＣｏＯ－ＮｉＯ系氧敏材料的缺陷模型．并测量了ＭｇＯ－ＣｏＯ－ＮｉＯ材料的高温电导与氧分压的关系．在实验的基础上，研究了该材料的缺陷化学及电导特性，对其禁带宽度及缺陷的热力学参数进行了理论估算．实验结果与理论分析吻合得较好．     

煤巷锚杆支护的矿压监测

随着锚杆支护技术的不断推广应用,人们已经认识到矿压监测的重要性和必要性。因此对锚杆支护的矿区进行比较全面、系统的监测,并使监测工作走向正规化、日常化已势在必行。文章对矿压监测的方法及注意事项进行了论述。