重质粒子/NBR-PVC微孔阻尼复合材料的制备及其隔声性能

为了制备一种轻质高效的隔声材料,本研究以丁腈橡胶（NBR）和聚氯乙烯（PVC）共混为主体材料,采用一步模压发泡工艺制备了重质粒子（HMP）/NBR-PVC微孔阻尼复合材料。通过SEM、动态力学分析和声阻抗管测试探究了橡塑比对HMP/NBR-PVC复合材料泡孔结构、阻尼性能和隔声性能等方面的影响,并进一步对其隔声机制进行了分析。研究结果表明：微孔结构的存在增加了声能量在材料内部传播过程中的衰减,提高了HMP/NBR-PVC复合材料的隔声性能。NBR与PVC质量比为50：50的HMP/NBR-PVC微孔阻尼复合材料具有良好的泡孔结构、力学性能和阻尼性能,其隔声指数高达28.1 dB。这种质轻、质软且易加工的橡塑微孔阻尼复合材料对新型隔声材料开发与应用具有一定的指导意义。     

Tungsten Trioxide Nanostructures for Photoelectrochemical Water Splitting: Material Engineering and Charge Carrier Dynamic Manipulation

To address the energy crisis and environmental problems, the applications of solar energy have received intensive attention. Converting solar energy to hydrogen using a photoelectrochemical (PEC) cell is one of the most promising approaches to meet future energy demands. As an earth abundant metal oxide, tungsten trioxide (WO₃), which has a moderate band gap (2.5–2.7 eV), ideal valence band position, and high resistance to photocorrosion, has been widely utilized in PEC photoanodes. To obtain a WO₃ photoanode with high PEC efficiency, tremendous efforts have been made to improve the light absorption capacity, charge carrier dynamics, and oxygen evolution activity. In this report, the recent advances in WO₃ photoanode optimization, including morphology design, dopants doping, heterojunction fabrication, and surface modification are summarized. In this review, these developments and representative applications of WO₃ photoanodes in unassisted water splitting devices are also discussed. Finally, perspectives on the significant challenges and future prospects for the development of WO₃ photoanodes for PEC water splitting are provided.     

深蓝算法应用于GF-1 16m相机反演陆地气溶胶

高分一号卫星是我国发展的新一代高分辨率对地观测卫星,如何应用该数据进行环境空气监测是目前迫切需要解决的问题。在深蓝算法基础上,根据GF-1星16 m相机的波段特征,借助MODIS的地表反射率产品去除地表贡献,从蓝波段数据反演了陆地气溶胶,实现了深蓝算法在GF-1星16m相机的应用。在此基础上,收集了2014年8~11月过境北京地区的GF-1星16m相机数据进行了反演实验,结果表明:该算法获取的气溶胶反演结果较好地反映了气溶胶的空间分布。同时,利用同期的AERONET/PHOTONS北京站的地面监测数据进行了算法验证,结果表明,本算法与地面数据有较好的相关性,相关系数大约为0.9,但该算法结果明显高于地面观测结果,可能是MODIS与GF-1星16m相机的波段响应不同导致的结果。     

Recent progress in stability of perovskite solar cells

Perovskite solar cells have attracted significant attention in just the past few years in solar cell research fields, where the power conversion efficiency was beyond 22.1%. Now, the most important challenge for perovskite solar cells in practical applications is the stability issue. In this mini-review, we will summarize the degradation mechanism of perovskite solar cells, including the perovskite material itself and also the interfaces. While we also provide our opinion on improving the stability of perovskite solar cells.     

Collective Wetting of a Natural Fibrous System and Its Application in Pump‐Free Droplet Transfer

Novel wetting strategies in plants have inspired numerous notable biomimetic surfaces over the past decade, such as self‐cleaning surfaces mimicking the water repellency of lotus leaves and directional water transport surfaces imitating the slippery surface on carnivorous plants. Here, a new wetting behavior in dandelion seed (genus Taraxacum) is found, characterized by capturing a droplet inside it. The critical conditions required for wetting of the fiber assay in terms of the fibrous geometry and liquid surface tension are identified, and how these factors quantitatively affect the volume of the captured droplet is shown further. More importantly, the reverse process can be triggered by introducing a competitive liquid phase with smaller surface tension to the wetted fiber assay, as it is demonstrated by the release of the captured water droplet in oil. These results enhance the understanding on wetting of fibrous structures and would benefit the design of novel intelligent and responsive devices. This newly identified wetting behavior holds great potential for fine control and micromanipulation of liquid. As a demonstration, it is illustrated that the natural fibrous structure is capable of manipulating a small volume of liquid for droplet‐based multiplexed chemical reaction.     

Comparative Studies on Calculation Methods of Shear Behavior of Reinforced Concrete Beams of Chinese Modern Reinforced Concrete Buildings

In order to study the calculation methods of shear behavior of reinforced concrete beams of Chinese modern reinforced concrete buildings, this paper carried out tests on the concrete compressive strength of 12 Chinese modern concrete buildings, the mechanical properties of 66 rebars from different Chinese modern concrete buildings, and the concrete cover thickness of 9 Chinese modern concrete buildings, and the actual material properties and structural configurations have been obtained. Then, the comparison on calculation methods include the Chinese original calculation method, the Chinese present calculation method, the American present calculation method and the European present calculation method is studied with case analysis method. The results show that the Chinese original calculation method of shear behavior of reinforced concrete beams is based on the allowable stress calculation method, and the design safety factors are 3.55-4.00. The standard value of the compressive strength of concrete cubes is 8.48 MPa, the standard value of the concrete tensile strength is 1.20 MPa, the standard value of the yield strength of rectangular rebars is 229.56 MPa, and the standard value of the yield strength of round rebars is 276.82 MPa. The average value of the concrete cover thickness of beams and columns is 35.96 mm. In term of calculation area of hoop rebars of reinforced concrete beams, without considering earthquake loads, the Chinese original structural calculation method is safer than the Chinese present structural calculation method, but is more unsafe than the American present structural calculation method and the European present structural calculation method. The results can provide the support for structural safety assessments and repair designs of Chinese modern reinforced concrete buildings.     

基于蒸汽轮机的非能动IVR策略研究

针对某些压力容器布置较高的核电厂，实施熔融物堆内滞留（IVR）过程中溢出堆腔的水和/或安全壳内冷凝水无法依靠重力自然回流到堆腔，从而无法实现长期非能动IVR的问题，提出利用IVR实施过程中产生的水蒸气，使其推动蒸汽轮机做功，然后带动水泵将安全壳底部的水重新注入堆腔，从而建立蒸汽和水的循环，进而实现长期非能动IVR的策略；并对该策略进行详细的热工水力计算分析，从理论上论证了该系统的可行性。      

新型重量检测控制仪的设计与实现

现代工业的迅速发展带动了检测与控制技术的日益更新,同时对重量检测控制仪的安全性和可靠性也提出了更高的要求,为此设计了一套新型的重量检测控制仪.该检测控制仪主要由信号采集和显示控制两部分组成,其中信号采集部分用于采集、传输物体重量信息,显示控制部分则主要显示重量数据,并输出相应的状态控制信号,超重时能够自动地实现自我保护...     

溶液除湿空调系统在工业厂房应用的能耗分析

通过对深圳某工业厂房分别选用常规冷凝除湿空调系统和溶液除湿空调系统进行系统设计和理论计算分析,比较了两类空调系统的能耗及COP。在夏季室外设计工况下,常规冷凝除湿空调系统的COP为2.94,溶液除湿空调系统的COP为5.42。室外空气含湿量越小,对提高溶液除湿系统的性能越有利。溶液除湿空调系统在节能方面具有较大的优势。     

MXene及其复合材料在吸波和导热领域的研究进展

介绍了吸波和导热相关机理,结合MXene独特的二维层状结构及其丰富可调的表面官能团,系统综述了国内外MXene及其复合材料在吸波和导热领域的研究成果,为后续设计开发吸波/导热一体化材料提供借鉴,最后指出了目前具备吸波和导热功能的MXene材料存在的问题和面临的挑战,并展望了未来的研究方向。