双管板换热器的结构设计

双管板换热器为管壳式换热器的一种特殊结构。对一台固定双管板式换热器的结构设计和强度计算进行了阐述,其中包括选材、布管、管板的结构和间距、胀管和开槽尺寸等方面的设计和计算。     

一种双阴离子型水性紫外光固化聚氨酯树脂的制备

该文在利用二羟甲基丙酸作为亲水单体制备水性紫外光固化聚氨酯树脂的基础上,利用价廉易得的对氨基苯磺酸作为扩链剂,在扩链反应时引入磺酸基,制备一种双阴离子型水性紫外光固化聚氨酯树脂。该树脂在加入光引发剂后,经紫外光固化30s后,基本固化完全。通过研究亲水基团对树脂水溶性的影响发现,所制备的树脂较只含有羧基的单阴离子型水性紫外光固化聚氨酯树脂具有更好的水溶性,且树脂的水溶性随着亲水基团总含量的增加而提高。     

鼠疫组分疫苗F1抗原、rV抗原含量的检测及其质量控制

目的采用双抗体夹心ELISA法检测鼠疫组分疫苗中F1和rV的抗原含量。方法利用F1、rV抗原单克隆抗体,对鼠疫组分疫苗原液进行抗原鉴别试验;分别应用F1、rV抗原双抗体夹心ELISA法对疫苗原液进行抗原定量检测;验证A(l OH)3佐剂吸附抗原的完全性;将疫苗成品于4℃放置18个月,分别于1和18个月时取样,用建立的双抗体夹心ELISA法检测F1和rV抗原含量,分析抗原的稳定性;对3批鼠疫菌rV抗原原液3步纯化工艺进行验证。结果鼠疫组分疫苗原液中的F1和rV抗原具有良好的反应原性;用建立的双抗体夹心ELISA法检测4批F1和rV抗原原液中F1和rV抗原的含量与Lowry法检测结果的误差均在±20%以内;4批鼠疫组分疫苗离心后的上清液中均未检测到F1和rV抗原,表明A(lOH)3佐剂吸附抗原完全;4℃保存18个月,疫苗中的F1和rV抗原含量稳定;3批鼠疫菌rV抗原原液经阴离子交换层析、疏水层析、凝胶过滤层析3步纯化,rV抗原在纯度增加的同时,抗原含量也增加。结论已建立的F1、rV抗原双抗体夹心ELISA法可用于鼠疫组分疫苗中F1和rV抗原的定量检测。     

Systematic study of optoelectronic and transport properties of cesium lead halide (Cs2PbX6; X=Cl,Br, I) double perovskites for solar cell applications

A systematic density functional theory investigation of Cs₂PbX₆ (X = Cl, Br, I) double perovskites is presented. The lattice constants are computed after structure optimization and using Birch-Murnaghan equations, which agree to the experimental literature. The mechanical stability conditions satisfy Born criteria, and the ductile nature is evidenced by the calculated Poisson's (v) and Pugh's ratios (B₀/G) because all three double perovskites exhibit values higher than the respective critical values v = 0.26 and B₀/G = 1.75. A detailed study of the optoelectronic properties reveals these double perovskites as promising candidates for future optical devices due to their direct band gaps (within 0.45–2.54 eV) and large absorption coefficients 5.95 × 10⁵ cm⁻¹, which are suitable for solar cell applications. ZT calculations demonstrate minute variations within 200–800 K and computed parameter values are quite favorable for thermoelectric applications of these materials in the future. A p-type semiconducting nature is predicted by the computed thermoelectric properties. Additionally, computed refractive indices show Cs₂PbBr₆ and Cs₂PbI₆ exhibiting super-luminescent properties in the UV range. Therefore, the studied double perovskites provide further interest for future energy conversion and photonic based technologies.     

Double hysteresis loops and enhanced mechanical quality factor of Mn-doped 0.75PMN-0.25PT ceramics

Relaxor ferroelectric 0.75 Pb(Mg_1/3Nb_2/3)O₃-0.25PbTiO₃ (0.75PMN-0.25PT) ceramics with Mn-doping concentration of 0%, 1%, 2% and 3 mol% were prepared by two-step sintering. The phase composition, microstructure, dielectric property, ferroelectric property, piezoelectric property and electromechanical property were investigated. Results indicate that all ceramics exhibit pure perovskite phases and high density. Mn-doping induces some decrease in dielectric constant ε_r, dielectric loss tanδ, remnant polarization P_r, piezoelectric coefficient d₃₃, and electromechanical coupling coefficient k_p, while significant increase in mechanical quality factor Q_m and the figure of merit (FOM) of 0.75PMN-0.25PT ceramics. For 3 mol% Mn-doped 0.75PMN-0.25PT ceramics, Q_m enhances by 1449%, FOM increases by 923%, and tanδ decreases by 67%, which makes it more suitable for high power applications. Interestingly, double P-E loops are observed in 3 mol% Mn-doped 0.75PMN-0.25PT ceramics. The phenomenon was investigated by the symmetry-conforming principle of point defects and the internal bias field.     

Double layers glaze analysis of the Fujian export blue-and-white porcelain from the Witte Leeuw shipwreck (1613)

Witte Leeuw was a cargo ship owned and operated by the Dutch East Indian Company. The wreck of this vessel is known for yielding a comprehensive range of Jingdezhen manufactured, blue-and-white export porcelains, particularly kraak wares; together with Fujian blue-and-white export porcelains, known as Swatow wares. A large number of ceramic fragments have been recovered from this wreck and currently reside in collections at the Rijksmuseum. For this study nine ceramic specimens were selected for further investigation, with the aim of determining the structure, composition and manufacturing process of the double-layer glazes. Both digital optical microscopy and scanning electron microscopy were used to examine the glaze morphology and microstructure; whilst energy dispersive x-ray spectroscopy was utilised to measure the spatial distribution of chemical elements and to determine bulk elemental compositions. Raman spectroscopy was also trialled, with the technique being applied to the measurement of molecular vibrations within the silicon-oxygen network and associated alkali metal oxides, with the aim of identifying potential differences in the glaze layers. Examining the ceramic specimens, the blue decorations were applied between two layers of glaze, and the majority of the blue colour extends into the outermost layer, often exhibiting dissolution in the outer layer glaze. The two layers of the glaze appear to be formulated from different compositional recipes. Some export Swatow blue-and-white wares made in the Wanli Period (1573–1620) were glazed twice and fired twice.     

双摆提速工具在港深1604井的现场试验

双摆提速工具是一种抑制钻头或底部钻具的轴向、径向两个方向摆动的工具,它是依靠钻井液提供动力,依靠内部结构提高钻头切削地层的效率,从而达到钻井提速的目的,并能减少钻头磨损。详细阐述了双摆提速工具在大港油田唐家河区块港深1604井的应用情况,通过数据分析与邻井对比,有效地提高了机械钻速。     

冀东迁西角闪质岩石成因的微量元素模拟及图式的研究

基于微量元素定量模型的讨论和在超基性熔融体系中双重效应的研充,讨论了角闪质岩石原岩的成因来源并确立了多成因角闪质岩石的存在。其原岩可以是上地幔岩在超基性熔融体中演化的结果,或地幔早期分异、自身交代等形成机理。     

Transient memristive device based on lead-free double perovskite for secured data storage and artificial learning systems

Modern day electronic devices are fascinated by various indispensable activities for various schemes. Transient devices are one of those systems useful for disposable electronics. However, choice of materials is an integral part, because the material should be compatible with the required device application and can show transient nature at the same time. Most importantly, the material for the aforesaid application should not possess any environmental hazard. In this work, we have for the first time integrated non-toxic double perovskite material in transient memristive application. The Cs₂AgBiBr₆ integrated in between Au and indium doped tin oxide (ITO) electrode serves as the functional material and the proposed device exhibited dual-functional switching characteristics. The device could retain the reproducible and stable resistive memory feature along with high-density storage capacity. The threshold switching behavior is useful to realize selector device in cross-bar resistive memory architecture. Thus, the same device can be utilized simultaneously for both the application. In addition, the device could also demonstrate some basic synaptic functions. Finally, the modulation of device resistance could be ascribed to the establishment/dissolution of conductive path related to Br^? vacancy and Ag filaments. Interestingly, the device could also display transient behavior as the Cs₂AgBiBr₆ film and the device undergo rapid decomposition within 60 s in H₂O.     

汽车修补涂料色母用分散剂的选用

通过对树脂、颜料、分散剂和混合溶剂的选择和定量,合成了通用色母。用指研法检验色母的分散稳定性,用倾流法或指擦法检验颜料的流动性,介绍了影响色母分散稳定性和颜料流动性的因素和原理,着重讨论了汽车修补涂料色母的单色浆微脂技术中分散剂的复配分散。