Assembly and Property Study of a Keggin-Based Inorganic–Organic Supramolecular Compound

By introducing mixed organic ligands (pytz and 4,4′-bipy) into a Keggin POM system, a new Keggin POM-based supramolecular compound, [Cu₃(bipy)₄(pytz)₂(H₂O)₆][HSiMo₁₂O₄₀]₂·8H₂O (1) (pytz = 5-(pyridyl)tetrazolate, bipy = 4,4′-bipy) was hydrothermally synthesized and characterized by routine methods. Crystal structure analysis reveals that the title compound contains both right- and left-helical chains, and these helical chains are further connected together forming an interesting mesh network via sharing the [Cu₃(bipy)₄(pytz)₂(H₂O)₆] subunits. Finally, the 1D pillar-like chains link the mesh nets to construct a 3D supramolecular structure of 1. In addition, compound 1 shows good photocatalytic activity for the degradation of Rhodamine B dye.     

CuBr放电管中粒子数分布的测量

本文阐述了使连续、单模、稳频、环形染料激光通过CuBr放电管,在578.2nm跃迁线上进行放大和吸收的方法。得到了2P_(1/2)和2D_(3/2)能级的粒子数分布情况。用黄光自放大方法测出了随输入功率变化的578.2nm跃迁线上下两能级的反转粒子数。     

Patterning of YVO4:Eu3+ Luminescent Films by Soft Lithography

Ordered arrays of luminescent YVO₄:Eu³⁺ films with square (side length 19.17 ± 2.05 μm) and dot (diameter 11.20 ± 1.82 μm) patterns were fabricated by two kinds of soft lithography processes, namely, microtransfer molding (μTM) and microcontact printing (μCP), respectively. Both soft‐lithography processes utilize a PDMS elastomeric mold as the stamp combined with a Pechini‐type sol‐gel process to produce luminescent patterns on quartz plates, in which a YVO₄:Eu³⁺ precursor solution was employed as ink. The ordered luminescent YVO₄:Eu³⁺ patterns are revealed by optical micro­scopy and their microstructure, consisting of nanometer‐scale particles, is unveiled by scanning electronic microscopy (SEM) observations. Additionally, photoluminescence (PL) and cathodoluminescence (CL) were carried out to characterize the patterned YVO₄:Eu³⁺ samples. A strong red emission as a result of ⁵D₀–⁷F₂ transition of Eu³⁺ was observed under UV‐light or electron‐beam excitation, which implies that combining soft lithography with a Pechini‐type sol‐gel route has potential for fabricating rare‐earth luminescent pixels for next‐generation field‐emission display devices.     

精密丝网印刷机结构设计

丝网印刷机是LTCC多层基板制造设备中的关键设备之一,介绍了精密丝网印刷机的主要结构及其工作原理,阐述了该设备的关键技术与创新点,并展望了设备的市场前景.     

基于Z-score模型的学员分组答辩成绩组间差消除办法

答辩是常用的一种考核方式,在院校和企事业单位都用得很多,当参加答辩的人数过多时,通常采用分组的方式进行.采用常规的方法无法完全消除各组评分之间的组间差,有失考核的公正,必须引入算法才能消除各组评分的组间差.论文引入Z-Score标准化数据处理方法并对其进行改进,先将各组成绩经过平移、压缩后消除组间差,再将其变换回正常区...     

太赫兹医学成像研究进展

太赫兹波所具有的无损性以及大量生物分子在太赫兹频段的指纹特性,使其在医学成像领域有着良好的应用前景。本文首先简要概述了太赫兹的医学成像技术手段,其次分别介绍了太赫兹在离体、活体组织中成像的研究现状。生物组织中的水会对太赫兹波产生强吸收,使得成像对比度受限。目前,为了减少组织中的水对成像的影响,针对离体组织的太赫兹成像大多需要进行切片、脱水等预处理,活体中的成像则主要应用在浅表组织。文章重点介绍了活体成像中有望提高太赫兹成像对比度的纳米粒子造影剂,最后对太赫兹医学成像的发展进行了展望。     

红曲酸奶中乳酸菌变化情况研究

利用超声波浸提法提取红曲中的有效成分,将红曲水提取液与全脂奶粉混合发酵制成新型红曲酸奶。通过荧光原位杂交（FISH）技术跟踪发酵过程中乳酸菌含量的变化,结果表明：红曲酸奶中保加利亚乳杆菌和嗜热链球菌数量显著高于普通酸奶。发酵2 h时,红曲酸奶中保加利亚乳杆菌与嗜热链球菌菌体数量分别为普通酸奶的2.63和2.24倍;发酵5 h时,发酵接近终点,红曲酸奶中保加利亚乳杆菌与嗜热链球菌菌体数量分别为普通酸奶的2.29和2.75倍。红曲酸奶的保藏期可达15 d,乳酸菌数符合国家标准的要求。     

含糖量对山葡萄酒苹果酸-乳酸发酵的影响

以东北高寒地区产的山葡萄酿造的山葡萄酒为研究对象,探究山葡萄酒苹果酸-乳酸发酵过程中含糖量对其pH值、总酸、苹果酸-乳酸转化程度、总糖的影响。山葡萄酒中的葡萄糖含量对其pH值的升高、总酸的降低及苹果酸乳酸转化程度均有影响。在4个梯度葡萄糖含量的山葡萄酒中,含糖量为10.67 g/L的山葡萄酒其pH升高值（0.18）、总酸度降低值（6.05 g/L）最大,苹果酸乳酸转化程度最高。     

A new method for online monitoring of boiling process in mini-channels

A new method for online monitoring of boiling process, which is suitable for conductive fluids in mini-channels, is proposed with the introduction of contactless conductivity detection (CCD) technique and perceptron algorithm (PA) technique. Series resonance principle and simulated inductor technique were adopted to develop a new CCD sensor. PA was used to implement the boiling stage identification, i.e., to identify the current stage was which stage of the boiling process. Three prototypes of the CCD sensors with inner diameters of 1.6, 2.0, and 2.5 mm were developed. With three kinds of conductive fluids (tap water, ethanol–tap water mixture, and KCl solution), boiling experiments were carried out. The experimental results show that the CCD sensor can effectively track the bubble growth of boiling process. The research results also indicate that the proposed method is effective and the identification accuracies are greater than 90.0%. © 2019 American Institute of Chemical Engineers AIChE J, 65: 1365–1375, 2019