电子功能模块测试用浮动插头装置的研究

本文针对电子功能模块PIN针的质量好坏,提出一种研究检测方法。本文提出一种测试装置,所述装置包括:一个用于固定电子功能模块浮动连接于其上的工件定位机构;若干探针,每根对于该本体上下伸缩的用于与所述PIN针接触的探头,以及一圈设置在所述本体外缘的轴肩;以及一个探针夹装机构。本装置有利于实现自动化操作,能够同时对电子功能模块上的PIN针进行测试,并且简单方便、效率高且效果好。     

Entrapping multifunctional dendritic nanoparticles into a hydrogel for local therapeutic delivery and synergetic immunochemotherapy

Nano Research - Developing multifunctional nanoparticles to support new therapy models is a promising and challenging task to address the current dilemma on antitumor treatment. Herein, we...     

一类n维Lotka—Volterra模型的稳定性特征

本文给出n维Lotka-Volterra合作系统局部渐近稳定性和全局稳定性的判别条件,并证明该系统正平衡位置的稳定性特征:局部渐近稳定性和全局稳定性是等价的.     

碳化硼加入量对氧化镁-氮化硅铁浇注料力学性能的影响

以97烧结镁砂为主要原料,加入3%质量分数的氮化硅铁细粉,以硅微粉作为结合剂,研究了外加不同量碳化硼(其质量分数分别为0、0.1%、0.2%、0.3%、0.4%、0.5%)对镁质浇注料常温物理性能和高温力学性能的影响,并借助扫描电镜对浇注料的显微结构进行了分析。结果表明:随着碳化硼加入量的增加,浇注料烘干强度下降,中、高温处理后强度变大,高温抗折强度下降。原因在于碳化硼在加热过程中氧化产生液相,促进材料烧结,使得材料致密,冷态强度增大;而由于液相的产生降低了镁质材料的直接结合程度,使得高温抗折强度减小。     

Carbon and sulfur cycling by microbial communities in a gypsum-treated oil sands tailings pond

Oil sands tailings ponds receive and store the solid and liquid waste from bitumen extraction and are managed to promote solids densification and water recycling. The ponds are highly stratified due to increasing solids content as a function of depth but can be impacted by tailings addition and removal and by convection due to microbial gas production. We characterized the microbial communities in relation to microbial activities as a function of depth in an active tailings pond routinely treated with gypsum (CaSO(4)·2H(2)O) to accelerate densification. Pyrosequencing of 16S rDNA gene sequences indicated that the aerobic surface layer, where the highest level of sulfate (6 mM) but no sulfide was detected, had a very different community profile than the rest of the pond. Deeper anaerobic layers were dominated by syntrophs (Pelotomaculum, Syntrophus, and Smithella spp.), sulfate- and sulfur-reducing bacteria (SRB, Desulfocapsa and Desulfurivibrio spp.), acetate- and H(2)-using methanogens, and a variety of other anaerobes that have been implicated in hydrocarbon utilization or iron and sulfur cycling. The SRB were most abundant from 10 to 14 mbs, bracketing the zone where the sulfate reduction rate was highest. Similarly, the most abundant methanogens and syntrophs identified as a function of depth closely mirrored the fluctuating methanogenesis rates. Methanogenesis was inhibited in laboratory incubations by nearly 50% when sulfate was supplied at pond-level concentrations suggesting that in situ sulfate reduction can substantially minimize methane emissions. Based on our data, we hypothesize that the emission of sulfide due to SRB activity in the gypsum treated pond is also limited due to its high solubility and oxidation in surface waters.     

Flexible strain sensors based on epoxy/graphene composite film with long molecular weight curing agents

Flexible strain sensors based on epoxy/graphene composite film with long molecular weight curing agents have critical roles in the development of advanced polymer composite films that combine mechanical robustness with functional properties such as electrical conductivity for many applications. In this experiment, flexible epoxy/GnP composite film is obtained by using flexible curing agent J2000. A percolation threshold of electrical conductivity was observed at merely 0.97 vol% GnPs, and the composite electrical conductivity increased to 10⁻⁶ S/cm at 5.0 vol %. The composite films were mechanically strong enough to be used as a flexible strain sensor. Our sensor can clearly detect the stretching of the forearm skin caused by a fist pulse and back of hand movement and achieve an enhancement of the resistance signal of up to 50%. When the GnPs content reaches 5%, Young's modulus and tensile strength increase to 21 MPa and 1.3 MPa, respectively. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47906.     

国产色谱柱HPLC法测定竹子乙醇精炼液中单糖与小分子脂舫酸

乙醇的存在会严重干扰HPLC法对竹子乙醇精炼液中甲酸、乙酸和丙酸等小分子脂肪酸和各种降解糖的检测.研究了国产氨基色谱柱检测单糖、C-18色谱柱检测小分子脂肪酸的效果.结果表明,氨基柱在流动相乙腈与水体积比75:25、进样体积1 μL、体积流量1.01 mL/min、时间15 min和温度30℃条件下,葡萄糖、木糖、阿拉...     

Facile Synthesis of Anatase TiO<Subscript>2</Subscript> Nanospheres as Anode Materials for Sodium-Ion Batteries

Anatase TiO₂ nanospheres (ATNSs) were successfully prepared through a facile solvothermal method followed by a thermal treatment. The sample was characterized by scanning electrons microscopy, transmission electron microscopy, x-ray diffraction, Raman spectrum and nitrogen adsorption techniques. When tested as an anode material for sodium-ion batteries, the electrode of ATNSs delivered a large discharge capacity of 208 mAh g^?1 after 100 cycles at a current density of 50 mA g^?1, indicating excellent cycling performance. This could be attributed to the uniform structure of the nanospheres with large surface area and porous nature, providing more active sites, buffering volume change, and facilitating the sodium ion intercalation as well as rapid diffusion during the charge/discharge process. Cyclic voltammetry demonstrated that the sodium storage mechanism is mainly controlled by pseudocapacitive behavior, resulting in a large capacity and outstanding cycling stability.     

超早强聚羧酸对低坍落度混凝土流变与气泡结构经时变化的影响

分别采用两种超长侧链聚羧酸减水剂与一种常规聚羧酸减水剂制备低坍落度混凝土,通过测试分析湿筛砂浆流动度、流变性、气泡结构参数以及三维重构气泡形态,对比研究了超长侧链聚羧酸减水剂对混凝土工作性能与气泡特征经时变化的影响.结果表明:低坍落度混凝土湿筛砂浆符合宾汉姆流体特征,流动度与屈服应力具有强线性相关性,减水剂种类对其影响较小,但超长侧链聚羧酸对砂浆流动度的经时保持作用明显弱于普通聚羧酸.超长侧链聚羧酸在砂浆中的引气数量和小孔径气泡占比均低于普通聚羧酸,并且超长侧链聚羧酸加速了砂浆中小孔径气泡向大孔径气泡的转变.CT三维重构试验直观地证实了砂浆中相邻小气泡聚并成大气泡现象的存在,超长侧链聚羧酸使得砂浆中气泡聚并发生的时间比普通聚羧酸更早.