对TBP萃取硫氰酸及硫氰酸铀酰机理的研究

很多金属离子都能和硫氰酸根形成相当牢的络合物,因此研究其络合和萃取机理对分离和分析是很有用处的。在工业上已采用硫氰酸体系分离锆和铪。为了解决镧系和锕系元素的分离和分析,人们也对他们的硫氰酸络合物作了很多的研究。关于铀(Ⅳ和Ⅵ价)的硫氰酸络合物的研究也曾有过一些报导,但是对用TBP萃取硫氰铀酰机理的详细研究尚没有见到报导。本文不仅用萃取——分光光度法计算出了硫氰酸铀酰络合物的络合稳定常数和热力学参数,而且还确定了用TBP萃取硫氰酸和硫氰酸铀酰的萃取类型、萃合物组成、萃合常数及萃取反应的温度效应等。     

Al（OH）3胶体的制备及其对铀的吸附机理

为了研究在地浸采铀中胶体对矿层的阻塞及对铀酰离子吸附迁移影响,采用硝酸铝与氨水为原料制备Al（OH）₃,并用在pH = 6条件下制备所得的Al（OH）₃对铀进行吸附实验研究,考察了吸附的pH值、初始浓度及吸附时间等对Al（OH）₃吸附铀的影响。对实验数据使用准一级、复合二级与Elovich 动力学模型进行计算与分析,得出Elovich 动力学方程更适合描述Al（OH）₃对铀吸附,吸附主要是表面吸附;使用 Freundlich与Langmuir等温吸附方程对实验数据进行拟合,结果表明Langmuir模型更适合描述Al（OH）₃对铀酰离子的吸附;对吸附前、后的Al（OH）₃进行SEM与激光粒度分析。     

紫外-可见分光光度法进展

主要介绍紫外－可见分光光度法常用试剂与反应，常用的分析分离技术（流动分析、动力学光度法、固相光度法等）和信号处理技术。     

一例两性离子配体铀酰配合物的合成及荧光响应

用一种两性离子配体,1,1’,1’’-（1,3,5-三甲基苯-2,4,6-三取代）-三亚甲基-三（吡啶-4-羧酸）三氯（H₃LCl₃）,与硝酸铀酰反应得到了一个铀酰配合物,通过X-射线粉末衍射（XRD）进行了表征。使用荧光分光光度法,研究了配合物对不同浓度、不同溶剂、不同金属离子的荧光响应。     

各类水体中铝的监测技术研究进展

本文论述了水体中铝元素的来源,絮凝沉淀剂的使用是水体中铝元素的重要来源。对分光光度法、无火焰原子吸收分光光度法、电感耦合等离子体发射光谱法（ICP/AES）和电感耦合等离子体质谱法（ICP/MS）等检测分析方法进行了探讨,并对其进行了简要的评价。     

直接紫外分光光度法测定硬脂酰氯的含量

提出了一种检测硬脂酰氯的直接紫外分光光度法,并与酸碱滴定法、银定量滴定法、酯化分光光度法及氯化银浊度法等进行了对比分析。结果表明:采用直接分光光度法检测硬脂酰氯,稳定性和精确度高,操作简单,分析时间短,无需对样品进行特殊处理,准确快速,可为工业生产提供及时可靠的数据分析。     

两种过氧化氢检测方法的对比研究

制备了辣根过氧化物酶/聚乙烯醇缩丁醛/碳纳米管修饰玻碳电极的过氧化氢生物传感器。以对苯二酚为电子媒介,采用电流时间法考察了该传感器对H2O2的催化性能,并将其与紫外分光光度法检测过氧化氢进行对比研究。结果表明,过氧化氢电化学传感器制备方法简便、操作简单、检测快速、线性范围宽、检出限低,而紫外分光光度法在重现性、稳定性及抗干扰性能上存在优势。     

磁性纳米材料处理含铀废水的研究进展

磁性纳米材料具有较强的化学稳定性、可再生回收、良好的吸附性能和易于分离等优点,在去除水溶液中的铀酰离子方面有广泛的应用前景。然而,磁性纳米材料也存在易团聚、易氧化等不足,通过表面修饰或改性等方法可改善其不足,提高其对废水中铀酰离子的去除能力,改善其吸附效果。本文通过总结近年来的相关研究资料,概括了磁性纳米材料的种类,归纳总结并比较了不同种类磁性纳米材料对含铀废水的去除能力及优势与不足,探讨了磁性纳米材料在含铀废水处理中的应用并对其机理进行了分析,阐述了磁性纳米材料去除溶液中铀酰离子的影响因素,简述了目前磁性纳米材料在处理含铀废水中有待解决的问题,并对其在分离放射性元素方面的应用前景进行了展望。     

CdSe@ZnS量子点荧光传感器在水体铜离子污染检测中的应用

使用微流控技术连续合成CdSe@ZnS核壳型量子点,并使用巯基丙酸对其进行表面改性,制备出可以被铜离子淬灭的水溶性CdSe@ZnS核壳型量子点。随后以聚乙烯醇（PVA）水凝胶为骨架,将改性后的量子点通过氢键作用力负载于骨架上,得到制备工艺简单、热稳定性高的复合荧光传感器件。该传感器的荧光强度随水溶液中铜离子浓度呈线性负相关关系,检测灵敏度可达20 μmol/L。其简便的操作和敏感的响应使之与原子吸收分光光度法形成优势互补,适用于水体铜离子污染的原位检测。该负载方法具有一定普适性,提供了将任意量子点制成器件应用于某种金属离子检测的新方式,实现了可回收的、环境友好的重金属离子快速检测目的。     

光化学传感器在检测环境中重金属的研究进展

重金属作为一种持久性污染物严重威胁着生态环境和人类健康,发展高效、快速、灵敏的重金属检测手段和分析方法具有很重要的意义。传统的检测技术存在仪器设备昂贵、检测过程繁琐、时性差等缺陷,难以满足当前检测工作的需要。光化学传感器作为一种选择性好、灵敏度高、分析速度快、成本低等多种优点的高新技术化学传感器,能在复杂体系中进行在线连续监测,广泛应用于化学、环境科学、食品和生命科学等领域。综述了近年来常用的光化学传感器及其在环境中重金属检测方面的应用,并对环境中重金属离子检测方法进行了讨论和展望,旨在为重金属污染物检测研究的发展和进步提供参考。     

Extended structures and physicochemical properties of uranyl-organic compounds

The ability of uranium to undergo nuclear fission has been exploited primarily to manufacture nuclear weapons and to generate nuclear power. Outside of its nuclear physics, uranium also exhibits rich chemistry, and it forms various compounds with other elements. Among the uranium-bearing compounds, those with a uranium oxidation state of +6 are most common and a particular structural unit, uranyl UO(2)(2+) is usually involved in these hexavalent uranium compounds. Apart from forming solids with inorganic ions, the uranyl unit also bonds to organic molecules to generate uranyl-organic coordination materials. If appropriate reaction conditions are employed, uranyl-organic extended structures (1-D chains, 2-D layers, and 3-D frameworks) can be obtained. Research on uranyl-organic compounds with extended structures allows for the exploration of their rich structural chemistry, and such studies also point to potential applications such as in materials that could facilitate nuclear waste disposal. In this Account, we describe the structural features of uranyl-organic compounds and efforts to synthesize uranyl-organic compounds with desired structures. We address strategies to construct 3-D uranyl-organic frameworks through rational selection of organic ligands and the incorporation of heteroatoms. The UO(2)(2+) species with inactive U═O double bonds usually form bipyramidal polyhedral structures with ligands coordinated at the equatorial positions, and these polyhedra act as primary building units (PBUs) for the construction of uranyl-organic compounds. The geometry of the uranyl ions and the steric arrangements and functionalities of organic ligands can be exploited in the the design of uranyl--organic extended structures, We also focus on the investigation of the promising physicochemical properties of uranyl-organic compounds. Uranyl-organic materials with an extended structure may exhibit attractive properties, such as photoluminescence, photocatalysis, photocurrent, and photovoltaic responses. In particular, the intriguing, visible-light photocatalytic activities of uranyl-organic compounds are potentially applicable in decomposition of organic pollutants and in water-splitting with the irradiation of solar light. We ascribe the photochemical properties of uranyl-organic compounds to the electronic transitions within the U═O bonds, which may be affected by the presence of organic ligands.     

Functional magnetic nanoshells integrated nanosensor for trace analysis of environmental uranium contamination

Transuranic radionuclides such as uranium tend to be a pervasive environmental contaminant. It is absorbed through the intestine or a lung, deposited in the tissues, predominantly kidney and bone, and is carcinogenic. A novel nanosensor system has been developed for voltammetric tracing of environmental uranium contamination.The sensor consists of an organophosphorous ligand, (t-butylphenyl)-N,N-di-(isobutyl) carbamoylmethylphosphineoxide (CMPO) functionalized superparamagnetic core-shell magnetic nanoparticles and magnet based electrodes. It exploits the natural affinity of uranium for phosphate molecules to fabricate a highly specific and reproducible sensor. The small dimension along with a dramatically increased contact surface has lead to a faster response and higher sensitivity. The system uses an external magnetic field gradient for preconcentration and removal of the analyte from the surrounding aqueous media. The redox properties of the analyte are exploited for enumeration of variables by electrochemical techniques such as square wave voltammetry. The detection limit of the system is observed to be in parts-per-billion (ppb) of the uranyl concentration.     

铀酰配合物高效识别水溶液中Fe3+的性质研究

基于含氮的柔性三羧酸配体异氰脲酸三(2-羧乙基)酯(H3tci),合成了一个具有二维空间结构的铀酰配合物(UO2(tci)·2H2O),通过X射线单晶衍射的方法测定了其晶体结构.在水溶液中,研究了该铀酰配合物对过渡金属离子的荧光作用,结果显示,该配合物对Fe3+有较好的敏感性.进一步的探索实验表明,该配合物可以高选择性...     

Graphene and MXene-based Sponge Pressure Sensor Array for Rectal Model Pressure Detection

Flexible sensor is one of the prevalent directions in the sensor field, and the sensing material and structure are the main aspects that affect the performance of the sensor. This paper studies a flexible pressure sensor based on Graphene/MXene-PDMS @ sponge. Using the porous skeleton structure of sponge and the high conductivity and synergy of Graphene and MXene to prepare a set of high sensitivity (0.053kPa⁻¹), high stability (2000 cycles loading), and variability (0–35 kPa detection limit), all-in-one sensor. In the rectal model pressure detection experiment, the sensor array can effectively detect static pressure, systolic pressure, and corresponding abnormal pressure detection. Experimental results show that the sensor has a good prospect in detecting rectal pressure.     

A negative resist,LMR (low molecular weight resist), for deep UV lithography

A negative deep UV resist, LMR, has been developed. LMR is a diazonaphthoquinonesulfonate of cresol novolac resin and possesses a high sensitivity of 15 mJ/cm² and a high resolution up to 0.2 μm by contact printing. An important feature of LMR is the production of negative images with overhung profiles. Such profiles are attributed to LMR possessing a large absorbance in the deep UV region (12 μm^?1 at 250 nm), which is of great advantage to the lift-off process in the fabrication of GaAs-FET, surface acoustic wave (SAW) devices, and so on. Furthermore, because of the good thermal stability of LMR, it can liftoff hard metals such as Ni and Mo. In order to elucidate the phenomenon that deep UV irradiation retards the dissolution rate of LMR, a mechanistic study has been carried out. In both LMR and its analog lacking diazoquinone moiety, their molecular weights Increase upon deep UV irradiation, which suggests that crosslinking occurs in the base resin. This is supported by 13C NMR analyses of photochemical reaction products and by detection of radical species produced from the base resin. The photochemical reaction of the base resin is important to understand the overall lithographic performance of LMR.     

Structural and Luminescence Studies on Barium Sodium Borosilicate Glasses Containing Uranium Oxides

Barium sodium borosilicate glasses containing different amounts of uranium oxides were prepared by conventional melt quench method and investigated for their structural aspects by ²⁹Si and ¹¹B MAS NMR technique combined with steady‐state luminescence and lifetime measurements. Based on MAS NMR studies, it is confirmed that uranium ions act as network modifier up to 15 wt% and beyond which a separate uranium containing phase is formed. From the luminescence studies, it is inferred that uranyl species is in a highly distorted environment. For more than 15 wt% uranium oxide incorporation, weaker U–O–U linkages are formed at the expense stronger U–O–Si/B linkages, as suggested by the excited state lifetime value of the uranyl species as well as red shift in emission peak maximum. For glass samples containing more than 25 wt% uranium oxides, crystalline barium uranium silicate gets phase separated from glass matrix as confirmed by XRD studies.     

测定空气中氢气的光化学传感器的研究进展

氢气是工业生产中常用的易燃易爆气体,因此研究用于空气中氢气浓度的快速监测的传感器有着重要的现实意义.本文综述了近年来用于测定空气中氢气的光化学传感器的研究现状和工业应用前景.     

腐植酸对叔胺萃取铀的影响

简要叙述了腐植酸的主要性能,论述了腐植酸对叔胺-煤油溶液萃取铀和反萃取铀过程的影响。腐植酸与腐植酸铀酰盐对叔胺-煤油溶液萃取铀将降低萃取效率,并形成乳化。在反萃取铀过程中,实践表明,采用腐植酸脱除剂Na2CO3作为反萃取剂进行反萃取,可以有效把叔胺-煤油溶液中负载的铀、腐植酸铀酰盐以及腐植酸反萃取下来,铀的反萃取率达98%以上,腐植酸的脱除率达99%以上;且两相之间无乳化膜。     

基于SVDD的冷水机组传感器故障检测及效率分析

传感器是制冷空调系统的重要组成部分,起着测量数据和监控状态的作用。传感器故障,尤其是输出偏差会引起测量值不准,影响控制策略,导致系统能耗增加。依据模式识别理论,故障检测可处理为一种单分类问题。据此采用一种单分类模式识别工具——支持向量数据描述(SVDD),针对冷水机组进行了偏差故障条件下的传感器故障检测工作。收集冷水机组实测正常运行数据,基于训练集建立SVDD模型,进行冷水机组传感器故障检测;在测试集中引入不同幅值水平的偏差故障,分析检测效率。结果表明:基于SVDD的冷水机组传感器故障检测效果明显,但对于不同传感器的不同幅值偏差故障,故障识别程度并不一致。     

A Polyester/Polypyrrole Textile-Based Ultrasensitive Wearable Microdistance Sensor

Microdistance sensor, which can accurately detect the microdistance change, possesses significant applications in the cutting-edge technologies including biomedicine, energy storage, and info-communications. However, the high cost, complicated operation, and stringent testing requirements of the existing microdistance sensors limit their widespread application in the frontier fields, especially for the intelligent wearable electronics. Herein, a novel mechanism to detect microdistance change is developed, in which the external microdistance brings a change in the thickness of conductive textile and further converts into a distinguishable electrical signal. The polyester/polypyrrole (PET/PPy) conductive textile is fabricated via in situ solventless polymerization, and the derived microdistance sensor exhibits an ultrahigh sensitivity of 179 m⁻¹ within the detection region of 10–480 µm, a high resolution up to 5 µm, and good stability. The excellent sensing performance can be attributed to the high elasticity, deformation-recovery property, and 3D network structures of the PET/PPy conductive textile. Furthermore, the wearable sensor is applied to detect the microdistance changes in human and robot activities, providing an efficient and low-cost solution for microdistance detection in intelligent medical, health monitoring system, and biomimetic robot.