热湿地区室内挥发性有机物多源散发研究现状

分析热湿地区室内空气污染现状,对影响热湿地区室内空气污染因素的独特特征进行总结。介绍国内外热湿环境下挥发性有机物多污染源散发机制的研究现状,指出湿热条件下室内装修家具等具有多污染源的挥发性有机物散发模型及环境影响因素研究的不足,提出对室内温度场、风速场、湿度场、污染物浓度分布进行模拟仿真的研究方向。     

Preparation and Characterization of TiN Seed Layer in All-Conductive Multilayer Structure for Coated Conductors

TiN films were successfully prepared on biaxially textured Ni-5 at.%W substrates by pulsed laser deposition (PLD), serving as a seed layer of an all-conductive architecture, i.e., SrRuO₃(SRO)/TiN, for coated conductors. The structure and surface morphology of the TiN films were noticeably affected by the substrate temperature and pulse repetition rate. The subsequent conductive SRO and superconducting YBCO layer were deposited on the best sample of TiN buffered Ni-5 at.%W substrates. X-ray diffraction analysis confirmed that the biaxial textures were transferred from the TiN seed layer to the SRO cap layer and YBCO film with excellent out-of-plane and in-plane textures. The superconducting transition curves and the temperature-dependent resistivity of YBCO films on all-conductive buffer and on the traditional insulated CeO₂/YSZ/Y₂O₃ were also investigated.     

Stability and Half-Metallicity of the (001) and (111) Surfaces of RbN with Cesium Chloride Structure

Using the full-potential local orbital minimum-basis method, we study the electronic and magnetic properties of relaxed (001) and (111) surfaces of the bulk RbN within the framework of density functional theory. It is shown that the Rb(N)-terminated (001) surfaces as well as the N-terminated (111) surface are the half-metallicity, while the Rb-terminated (111) surface loses the half-metallicity. The atomic magnetic moments at the N-terminated (001) and Rb(N)-terminated (111) surfaces increase considerably with respect to the corresponding bulk values. In addition, calculations reveal the half-metallicity of the N-terminated (111) surface is more robust than the bulk RbN due to its larger half-metallic gap. Finally, we discuss the stability of the surface. The positive formation energy in the bulk RbN indicates the surfaces unstable, and non-equilibrium growth techniques may be required for the realization of RbN thin films.     

Optimizing the Size of Micellar Nanoparticles for Efficient siRNA Delivery

Delivery of small interfering RNA (siRNA) by nanocarriers has shown promising therapeutic potential in cancer therapy. However, poor understanding of the correlation between the physicochemical properties of nanocarriers and their interactions with biological systems has significantly hindered its anticancer efficacy. Herein, in order to identify the optimal size of nanocarriers for siRNA delivery, different sized cationic micellar nanoparticles (MNPs) (40, 90, 130, and 180 nm) are developed that exhibit similar siRNA binding efficacies, shapes, surface charges, and surface chemistries (PEGylation) to ensure size is the only variable. Size‐dependent biological effects are carefully and comprehensively evaluated through both in vitro and in vivo experiments. Among these nanocarriers, the 90 nm MNPs show the optimal balance of prolonged circulation and cellular uptake by tumor cells, which result in the highest retention in tumor cells. In contrast, larger MNPs are rapidly cleared from the circulation and smaller MNPs are inefficiently taken up by tumor cells. Accordingly, 90 nm MNPs carrying polo‐like kinase 1 (Plk1)‐specific siRNA (siPlk1) show superior antitumor efficacy, indicating that 90 nm could either be the optimal size for systemic delivery of siRNA or close to it. Our findings provide valuable information for rationally designing nanocarriers for siRNA‐based cancer therapy in the future.     

Navigating Organo‐Lead Halide Perovskite Phase Space via Nucleation Kinetics toward a Deeper Understanding of Perovskite Phase Transformations and Structure–Property Relationships

Organo‐lead halide perovskite photovoltaics have developed faster than our understanding of the material itself. Using the vast body of work on perovskite processing created in just the past few years, it is possible to create a better picture of this material's complex phase‐transformation behavior. This concept paper summarizes and correlates the current understanding of structural intermediates, kinetic controls, and structure–property relationships of organo‐lead iodide perovskites. To this end, a new way of graphically relating information is developed, allowing the simultaneous mapping of schematic kinetic relationships between all currently prevailing perovskite deposition and growth techniques.     

富钛料在低浓度碱液中的水热反应研究

以富钛料为原料,研究其在Na OH溶液中水热反应的行为,应用Box-Behnken中心组合设计原理和响应面分析法研究了碱浓度、温度、反应时间等条件对Ti O2转化率的影响。结果表明:在碱浓度25%、温度186℃、反应时间4 h的条件下,得到的产物转化率最高,并在最优条件下验证了其转化率。采用扫描电子显微镜(SEM)及X-射线衍射仪(XRD)分析了反应产物的形貌及物相表征,表明在不同条件下得到了不同的反应产物,其形貌随着条件的不同逐渐发生改变。     

ICP—MS法测定高纯碳化硅粉表面的痕量杂质

本文采用ICP-MS法对高纯碳化硅粉表面的Na、Al、Ti、V、Cr、Mn、Fe、Co、Ni、Cu、Zn、Cd 12种痕量杂质进行测定,用氢氟酸溶液浸提试样表面杂质,用钆做内标补偿基体效应和仪器的漂移,用碰撞反应技术消除多原子离子干扰,通过实验确定最佳优化测定条件。方法检出限为0.005-0.036μg/L;加标回收率为80.0%-120.3%之间;RSD为1.78%-8.95%。方法操作简便、快速、准确。     

Novel Resonant Accelerometer with Micro Leverage Fabricated by MEMS Technology

For the purpose of improving the precision of the inertial guidance system,it is necessary to enhance the accuracy of the accelerometer.Combining the micro-fabrication processes with resonant sensor technology,a high-resolution inertial-grade novel micro resonant accelerometer is studied.Based on the detecting theory of the resonant sensors,the accelerometer is designed,fabricated,and tested.The accelerometer consists of one proofmass,two micro leverages and two double-ended-tuning-fork (DETF) resonators.The sensing principle of this accelerometer is based on that the natural frequency of the DETF resonator shifts with its axial load which is caused by inertial force.The push-pull configuration of the DETF is for temperature compensation.The two-stage micro leverage mechanisms are employed to amplify the force and increase the sensitivity of the accelerometer.The micro leverage and the resonator are modeled for static analysis and nonlinear modal analysis via theory method and finite element method (FEM),respectively.The geometrical parameters of them are optimized.The amplification factor of the leverage is 102,and the sensitivity of the resonator on theory is about 62 Hz/g.The samples of the accelerometer are fabricated with deep reactive ion etching (DRIE) technology which can get a high-aspect ratio structure for contributing a greater sensing-capacitance.The measuring results of the samples by scanning electron microscopy (SEM) show that the process is feasible,because of the complete structure,the sound combs and micro leverages,and the acceptable errors.The frequency of the resonator and the sensitivity of the accelerometer are tested via printed circuit board (PCB),respectively.The result of the test shows that the frequency of the push-resonator is about 54 530 Hz and the sensitivity of the accelerometer is about 55 Hz/g.The amplification factor of the leverage is calculated more accurately because the coupling of the two stages leverage is considered during derivation of the analysis formula.In addition,the novel differential structure of the accelerometer can greatly improve the sensitivity of the accelerometers.     

多层压电陶瓷降压变压器的环境测试研究

电压增益、输出功率、效率是表征压电变压器(MPT)工作性能的3个重要参数。使用为华公司提供的径向振动型多层压电陶瓷降压变压器,测量其基本电学性能;温度对导纳圆等阻抗特性的影响;温度对其基本电学性能的影响等。综合研究降压变压器的环境温度稳定性。结果表明:压电变压器环境稳定性良好,但长时间剧烈的环境变化会对其使用性能产生一定影响,高温环境对其影响比较大。     

三头单螺杆泵定转子接触磨损分析

采用ANSYS软件对短幅内摆线外等距曲线及短幅外摆线内等距曲线2种线型的三头单螺杆泵在过盈及压差作用下的变形、受力及接触情况进行有限元分析,得到定转子接触时变形及应力分布云图,比较2种线型三头单螺杆泵的密封性能.结果表明:过盈量的存在是实现螺杆泵密封的重要条件;压差的存在使定子橡胶发生较大的变形,应力应变值也相应增加;短幅内摆线外等距曲线三头单螺杆泵密封性能优于短幅外摆线内等距曲线三头单螺杆泵.