摘要：In order to solve the heat damages in deep mines, a cool-wall cooling technology and its working model are proposed based on the principles of heat absorption and insulation in this paper. During this process, the differential equation of thermal equilibrium for roadway control unit is built, and the heat adsorption control equation of cool-wall cooling system is derived by an integral method, so as to obtain the quantitative relationship among the heat absorption capacity of cooling system, the heat dissipating capacity of surrounding rock and air temperature change. Then, the heat absorption capacity required by air temperature less than the standard value for safety is figured out by section iterative method with the simultaneous solution of heat absorption control equation and the heat dissipation density equation of surrounding rock. Finally, the results show that as the air temperature at the inlet of roadway is 25 ℃, the roadway wall is covered by heat-absorbing plate up to 39% of the area, as well as the cold water is injected into the heat-absorbing plate with a temperature of 20 ℃ and a mass flow of 113.6 kg/s, the air flow temperature rise per kilometer in the roadway can be less than 3 ℃.

摘要：该研究采集了15类废旧纺织物的4 998张近红外谱图,以7∶3的比例分为训练集和验证集,并分别采用主成分分析(PCA)与核主成分分析(kernal-PCA)两种不同降维方法对数据进行降维,并选用余弦相似度(cosine)核作为kernal-PCA的最佳核函数,最后分别将PCA和kernal-PCA降维处理后的数据进行k-近邻算法(KNN)训练。结果表明,kernal-PCA+KNN的模型准确率(95.17%)优于PCA+KNN模型的准确率(92.34%)。研究表明,kernal-PCA+KNN算法可以实现15类废旧纺织物识别准确率的提升,为废旧纺织物在线近红外自动分拣提供有力的技术支撑。

摘要：Due to the influence of dialect,many English learners in China tend to speak English in the way they usually speak during second language acquisition,which results in negative transfer on English *** order to reduce this phenomenon and improve the students’English pronunciation level,it is necessary for us to study the topic and put forward *** using the contrastive analysis,this paper compares the pronunciation of English,Chinese and Henan dialect so as to find out the influence of Henan dialect on English learners at segmental level and suprasegmental *** results show strong correlation between the pronunciation of English and Henan dialect for English ***,this paper analyzes the mistakes and reasons that learners of Henan province are prone to make in the process of learning,and puts forward corresponding suggestions for teaching on students’negative transfer,so as to enhance the awareness of negative transfer for teachers and students.

摘要：High-entropy alloys(HEAs)possess outstanding features such as corrosion resistance,irradiation resistance,and good mechan-ical properties.A few HEAs have found applications in the fields of aerospace and *** studies on the deformation mech-anisms of HEAs can guide microstructure control and toughness design,which is vital for understanding and studying state-of-the-art structural *** X-ray and neutron diffraction are necessary techniques for materials science research,especially for in situ coupling of physical/chemical fields and for resolving macro/microcrystallographic information on ***,several re-searchers have applied synchrotron X-ray and neutron diffraction methods to study the deformation mechanisms,phase transformations,stress behaviors,and in situ processes of HEAs,such as variable-temperature,high-pressure,and hydrogenation *** this review,the principles and development of synchrotron X-ray and neutron diffraction are presented,and their applications in the deformation mechanisms of HEAs are *** factors that influence the deformation mechanisms of HEAs are also *** review fo-cuses on the microstructures and micromechanical behaviors during tension/compression or creep/fatigue deformation and the application of synchrotron X-ray and neutron diffraction methods to the characterization of dislocations,stacking faults,twins,phases,and intergrain/interphase stress *** on future developments of synchrotron X-ray and neutron diffraction and on research directions on the deformation mechanisms of novel metals are discussed.

摘要：设计了一种应用于扫描电镜的四自由度并联定位平台.该平台结构简单,便于集成微操作装置和实现微结构物性在线检测.为使所设计的定位平台具有高的定位精度,建立了平台的误差矢量模型.通过模拟仿真手段分析了结构误差和上平台分支分布对平台末端定位精度的影响,分析了在大载荷作用下机构在非自由度方向产生的角位移输出.

摘要：为了扩展扫描电镜的用途,实现微结构物性在线检测,本文基于4-PUU并联机构设计了一种扫描电镜定位平台.其结构简单,便于集成微操作装置.为优化平台机构的性能,本文建立了4-PUU机构的空间尺寸模型,绘制了机构性能图谱,分析了机构参数对机构可达工作空间、灵巧性、速度性能的影响,得到了具有良好性能的平台机构参数.

摘要：针对目前LNG接收站消防设计无据可依的现象,结合LNG接收站的火灾危险性、国内外相关规范要求及实际经验,提出了此类场所消防设计的初步解决方案。

摘要：针对LCL型滤波器在DC/DC储能变换器的应用中,流过滤波电容的电流难以准确测量的问题,提出了一种电容电压内环反馈控制方法。首先依据蓄电池对充放电电流的要求,对LCL滤波器的参数进行了设计,以蓄电池侧电流为控制对象,加入滤波电容电压微分的反馈环节,增加系统阻尼,提高系统的稳定性。将LCL型滤波器应用到DC/DC储能变换器中,相比于传统的L型滤波器,可以大大减小滤波电感值,减小蓄电池充放电电流纹波,延长蓄电池寿命。最后通过仿真和实验验证了该方案的正确性和有效性。

摘要：多目标优化算法大多采用基于线性链表结构的有界Pareto存档策略,其存在迭代过程中Pareto前沿震荡衰退等弊端以及相关参数难以预先确定等技术难题.为此,构造一种适用于大规模存档集合的树形结构,并利用其取代线性结构以保证存档维护与管理的高效性,进而提出基于树形结构的无界存档策略.在此基础上,将基于正交设计的种群初始化、基于树形结构的存档更新以及基于树形结构的最优个体选择引入多目标粒子群优化,提出基于树形结构无界存档的多目标粒子群算法.最后,通过测试函数上的仿真实验验证了所提出策略与算法的科学性和有效性.

摘要：针对模块化多电平换流器(MMC)的相间环流问题,提出基于补偿分量的调制方法以便于降低MMC调制系数中的基频分量。首先通过结合实际系统中电容参数设计和换流器的正常运行范围,对MMC子模块电容电压纹波进行取值并求解其最大值,然后分析调制系数中抑制环流的补偿分量与电容电压纹波之间的数量关系,最终得到MMC最大调制系数的取值范围。仿真和实验验证的结果表明,通过对含有补偿分量的最大调制系数范围的确定,系统环流得到了有效抑制,避免了过调制现象的发生,有利于MMC系统的稳定运行。