两种消偏陀螺的轴向磁场灵敏度

运用琼斯矩阵,分别建立了轴向磁场作用下,单消偏陀螺系统和双消偏陀螺系统产生Faraday非互易相位差的理论模型.导出了两种系统的非互易相位差的表达式,并对其进行理论分析和仿真,最后给出两种系统轴向磁场作用下的实验结果.提出:采用双消偏系统并使得两个消偏器的45°误差之和趋于0,可以在很大程度上减小消偏陀螺的轴向磁场灵敏度.     

控制系统的一种直接盲辨识方法

提出一种在时域中直接盲辨识系统传递函数的方法。首先利用过采样方法，将SISO系统转换为具有相同零极点的SIMO系统进行处理；然后通过对新的SIMO模型先估计分子参数、后估计分母参数的方法，即可获得原SISO模型的参数估计。该方法也可用于辨识非最小相位系统。     

光纤中受激布里渊散射的应用及研究进展

简单介绍了光纤中受激布里渊散射的研究进展,阐述了受激布里渊散射在光纤传感器、光纤陀螺及相位共轭镜中应用的基本原理和研究现状以及光纤传感器、光纤陀螺和相位共轭镜目前的发展现状,评述了基于受激布里渊散射的传感器和相位共轭镜未来的发展前景。     

茂金属聚乙烯/茂金属乙烯-丙烯共聚物共混微观相结构与力学性能

采用密炼机制备了不同组成的茂金属聚乙烯/茂金属乙烯-丙烯共聚物(mPE/mEP)共混体系,利用在线取样-显微分析的方法研究了不同组成mPE/mEP共混体系的微观相态结构,在研究相态结构的基础上,研究了体系的力学性能。结果表明,mPE/mEP共混物呈现明显的两相结构,当mPE体积含量在50%~60%范围内,共混体系形成双连续相,其他组分含量时,形成"海-岛"结构形貌。共混物的拉伸强度与共混体系微观相形态的变化有关,断裂伸长率随着mPE含量的增加由2360%降至550%,拉伸模量随着mPE含量的增加由3.5MPa增至102MPa。     

多层岩盐矿爆破切割压裂工艺

多层岩盐矿（含芒硝矿）的开采，普遍采用分层建井回采工艺，即每回采一层盐，均需分别建一组回采井，回采费用高。该文介绍一种新的回采工艺－爆破切割全程裸露盐层，其特点是建一组回采井，采用爆破切割方法，将所有盐层裸露并予以回脂，大大降低回采费用，提高回采速度。     

Core–Shell Structure and Interaction Mechanism of γ‐MnO2 Coated Sulfur for Improved Lithium‐Sulfur Batteries

Lithium‐sulfur batteries have attracted worldwide interest due to their high theoretical capacity of 1672 mAh g^?1 and low cost. However, the practical applications are hampered by capacity decay, mainly attributed to the polysulfide shuttle. Here, the authors have fabricated a solid core–shell γ‐MnO₂‐coated sulfur nanocomposite through the redox reaction between KMnO₄ and MnSO₄. The multifunctional MnO₂ shell facilitates electron and Li⁺ transport as well as efficiently prevents polysulfide dissolution via physical confinement and chemical interaction. Moreover, the γ‐MnO₂ crystallographic form also provides one‐dimensional (1D) tunnels for the Li⁺ incorporation to alleviate insoluble Li₂S₂/Li₂S deposition at high discharge rate. More importantly, the MnO₂ phase transformation to Mn₃O₄ occurs during the redox reaction between polysulfides and γ‐MnO₂ is first thoroughly investigated. The S@γ‐MnO₂ composite exhibits a good capacity retention of 82% after 300 cycles (0.5 C) and a fade rate of 0.07% per cycle over 600 cycles (1 C). The degradation mechanism can probably be elucidated that the decomposition of the surface Mn₃O₄ phase is the cause of polysulfide dissolution. The recent work thus sheds new light on the hitherto unknown surface interaction mechanism and the degradation mechanism of Li‐S cells.     

Application of High-Speed Laser Polarimetry to Noncontact Detection of Phase Transformations in Metals and Alloys at High Temperatures

A high-speed laser polarimetry technique, developed recently for the measurement of normal spectral emissivity of materials at high temperatures, was used to detect solid–solid and solid–liquid phase transformations in metals and alloys in millisecond-resolution pulse-heating experiments. Experiments were performed where normal spectral emissivity at 633 nm was measured simultaneously with surface radiance temperature, resistance, and/or voltage drop across the specimen. It was observed that a phase transformation, as indicated either by an arrest in the specimen radiance temperature or changes in the resistance and/or voltage drop, generally caused a change in normal spectral emissivity. Experiments were conducted on cobalt, iron, hafnium, titanium, and zirconium to detect solid–solid phase transformations. Similar experiments were also performed on niobium, titanium, and the alloy 85titanium–15molybdenum (mass%) to detect solid–liquid phase transformations (melting).     

液晶分子在受限条件下的液晶相行为（Ⅱ）某些化学受限环境对液晶相行为的影响

综述了液晶分子在与聚合物嵌段、碳纳米管（CNT）和多面低聚倍半硅氧烷（POSS）等通过共价键形成的化学受限环境下的液晶相行为。聚合物嵌段微区的受限作用使侧链液晶嵌段共聚物的液晶有序度减小,相变温度降低。由于碳纳米管的受限作用,液晶聚合物接枝CNTs的有序结构被破坏,液晶性丧失。POSS以共价键的方式引入到液晶分子中,明显提高了液晶相的稳定性。但是当POSS含量高于某临界值后使液晶分子表现出单向性液晶相行为,甚至使其丧失液晶性。     

钛基梯度功能涂层磨损和腐蚀行为研究

为开发在超高温、大温差条件下具有热应力缓和功能的新型耐磨耐蚀涂层,在钛合金表面Nd∶YAG激光制备了梯度功能涂层,SEM观察了微观组织结构,XRD分析相组成并测定了摩擦磨损和耐腐蚀性能。结果表明原位自反应生成的TiC球状增强体弥散均匀分布在FGL中,微观组织为粗大和不完整的树枝晶、相对较细小的等轴和近等轴晶及细小短纤维状形态。FGL和N-FGM耐磨、耐蚀性能优异;摩擦系数和磨损率显著降低,其平均值是Ti600基体的0.3～0.5倍;腐蚀电流和电阻值分别为Ti600的0.72和1.31倍。     

(α+β)Dual Phase CuZnAl Shape Memory Alloy

The effect of α phase on CuZnAl shape memo-ry alloy(SMA)has been systematically studied byelectrical resistance method,quantitative measure-ment of micrography and transmission electronmicroscopy(TEM).It is found that,by controllingthe amount of α phase in(α+β)-CuZnAl alloy,phase transformation temperatures can be adjustedprecisely in a wide range,while the good shapememory effect of CuZnAl is kept.In a word,quenching from(α+β)dual phase region is a rea-sonable method of adjusting phase transformationtemperatures for CuZnAl alloy.