电流型电化学遥测系统的研制与应用

研制了一种微型嵌入式遥测系统,并利用此系统实现了电化学传感检测。遥测系统的输出电压范围为-0.5~0.5 V,分辨率<1 mV；电流检测范围为-1~1μA,最小分辨率为0.2 nA。此遥测系统是基于ADuCM360微处理器设计的,包括恒电位仪、电流检测模块和无线模块,尺寸大小为24 mm ×13 mm ×11 mm。利用LabVIEW开发上位机软件,用于数据存储和实时显示。为了验证该系统的精度和可靠性,对系统进行了电学性能测试。应用遥测系统检测不同浓度抗坏血酸溶液的电流响应,电极施加的工作电位为30 mV,在浓度范围50~300μmol/L 内,抗坏血酸电极的电流响应与其浓度呈现良好的线性关系,线性方程为I(nA)=2.98CAA(μmol/L)-137.39,线性相关系数R2=0.984。并以脑缺血模型为例,探索了仪器在活体动物研究中的适用性。结果表明,该系统可用于相关动物模型的研究。     

气体传感器气敏性能测试技术研究进展

对国内文献报道的气体传感器气敏性能测试系统的设计开发情况进行综述。从配气系统、数据处理系统、软件开发三个方面对半导体型气体传感器测试系统的组成进行了概述。配气系统为气敏性能测试提供一定浓度目标气体,分为静态配气法和动态配气法,动态配气法制备出的气体精确度较高,误差较小,可以连续制备气体,是目前主要配气方式。控制器是测试系统的核心部件,负责接收、处理、储存传感器与目标气体反应产生的信号,应用较多的是单片机,其次是ARM微控制器,但都存在内存和存储空间有限的问题。测试软件主要功能是发送指令,实现整个测试系统的有序运行,并实时显示测试结果,目前开发工具种类较多,其中LabVIEW较受青睐。未来气敏测试系统的测试精确度和测试效率还需进一步提高,研究开发功能更加全面的测试系统,来满足其它类型传感器测试需求。     

氧化钯作为电位型传感器中敏感电极的工作机理（英文）

研究了基于氧化钯(PdO)电极的电位型传感器的敏感特性,并探讨了其敏感机理。首先,利用Mg、Ni和La元素对PdO电极进行掺杂,将掺杂后的PdO电极印刷在氧化锆电解质上,制备成电位型传感器,并对一氧化碳(CO)的敏感特性进行了测试。由于掺杂后的PdO电极表面缺陷增加,这有利于对CO的吸附,有效地提高了传感器的灵敏度。其次,为了探究敏感信号的来源,PdO电极分别印刷在氧化铝和沸石基片上,同样测试了对CO的敏感特性。其中PdO电极与沸石所组成的电位型传感器对CO浓度可以产生阶梯型响应。最后,对传感器分别进行了电阻和阻抗谱的测量,测量结果表明:传感器的响应可以归因于电极和电解质之间界面电位的变化。综合上述研究结果,建立了电偶层模型来解释基于PdO电极的电位型传感器的工作机理。     

飞行时间质谱仪数据采集系统设计

针对飞行时间质谱仪高分辨率、宽质量范围的特点,设计了一种高精度、大量程的数据采集系统。系统对前端信号进行放大、幅度甄别和电平转换,使用专用时间间隔测量芯片TDC-GPX测量脉冲时间间隔,应用现场可编程门阵列(FPGA)进行时序控制,通过通用串行总线(USB 2.0)接口与计算机连接,采用时分复用技术实现上位机对采集系统的控制及高速数据传输。测试结果表明,单通道测量精度小于100 ps,测量范围大于500μs,可进行8个通道测量。     

用于在体神经递质检测的可佩戴式无线电化学检测仪

为了实现对微弱神经递质信号的在体实时检测,设计并实现了一种无线电化学检测仪器。系统硬件以低功耗微控制器MSP430为主控制器,包括了微弱电流检测模块、波形产生模块以及数据收发模块,具有尺寸小(2.3 cm×1.8 cm×0.6 cm),功耗低的特点。基于u C/OS操作系统设计了系统的下位机程序,结合上位机软件实现了检测数据的实时显示与分析。针对神经递质的实际检测需求,系统集成了计时电流法与快速循环伏安法两种电化学检测分析方法。利用快速循环伏安法对不同浓度的多巴胺标准溶液进行了测试,在浓度范围5.0×10#7~7.0×10#5mol/L内,系统检测的响应电流与多巴胺浓度之间线性相关系数R=0.99。在此基础上,开展了大鼠在体多巴胺检测的实验,并成功检测到大鼠尾状壳核脑区的电诱发多巴胺释放信号。实验结果表明,此仪器具有检测灵敏度高的优点,能够实现对大脑内神经递质信号的定性及定量分析,在神经科学研究领域具有广阔的应用前景。     

毛细管电泳微机化扫描伏安检测器

描述了一种毛细管电泳微机化扫描伏安检测器,用微机通过D/A和A/D转换器控制扫描电压和采集电流信号,用12bit的D/A转换器和12bit的A/D转换器通过伏安仪分别与Ag/AgCl参比电极和工作电极相连,进行电位控制和数据采集.讨论了扫描电位的产生和数据采集的控制方法,并用本系统分离测定了对苯二酚和儿茶酚,结果令人满意.     

高精度色谱数据采集系统

由双电压频率转换器(VFC)构成高精度色谱数据采集的方法,与常用的由变量程提高分辨率的方法相比,它不存在因信号突变而引起VFC无法快速响应的问题,系统采用双VFC同步工作机制,能在10Hz采样频率下达到2×10⁶的分辨率,具有实施简单、精度高、噪声小、价格低等特点,可广泛应用于各种分析化学信号采集。     

以伴刀豆球蛋白为固定基质的脲酶生物传感器

本文制备了一种以溶剂聚合膜pH电极作原电极,利用伴刀豆球蛋白(Con A)与糖蛋白间的特异性识别作用,将Con A和脲酶表面的麦芽糖残基结合,采用交替沉积Con A和脲酶,进行多层脲酶膜组装的脲酶生物传感器。研究了酶固定化条件的影响,优化了实验条件,测试了传感器对尿素的生物电化学响应。在6.9×10-5~1.0×10-3mol.L-1的浓度范围内传感器响应的电极电位与尿素浓度的对数成正比,检出限为4.5×10-5mol.L-1。将传感器用于牛奶样品中回收率的测定,结果满意。     

压电晶体传感器阵列在补体系统免疫分析中的应用

将压电石英晶体阵列应用于补体系统免疫分析中,从而发展了一种新型的同步免疫分析方法,并对补体系统的四种成分（C4,C5,C1q,B因子）进行了分析测试。通过对不同条件（即抗体效价不同）下的多组分分析物进行同步检测,研究了补体系统免疫反应的特性和该传感器阵列的响应特性。差频信号的测量消除了粘度、温度和电导率的影响,同时对该传感器阵列晶体间的干扰进行了测试。该方法操作简单、准确、灵敏度较高。     

大范围高灵敏度纳米尺度氨气传感器的制备

介绍了基于碳纳米管与聚苯胺纳米纤维的两种氨气传感器的制备与测试,综合运用两种传感器,兼顾了高灵敏度和大范围测量两项互相制约的要求.使用近场电纺技术制备单根聚苯胺纳米纤维传感器,对1×10-6氨气灵敏度达到2.7％,比较了聚苯胺纳米纤维结构和薄膜结构的响应特性.纳米纤维的立体结构可提升传感器性能.使用双向电泳技术制备碳纳米管传感器,对浓度大于20× 10-6 (V/V)的氨气有良好的线性响应.分析了主要功能材料的微结构,阐述了制备技术,比较了响应特性,分析了纤维中气体三维扩散模型,通过计算和测试值,表明响应时间与纤维直径存在反相关性.     

化学结构中互变键、交替键和芳香键的自动识别

化学结构计算机处理中最常遇到的困难是互变现象、交替键和芳香键的处理, 尽管解决这些问题的方法早有报道,但它们都有仅考虑计算机处理的方便,而很少 注意其化学应用的不足。本工作在环系识别算法的基础上,设计了新的识别算法, 使得识别的整体性能更好,形成了拥有自主知识产权的软件。简要介绍了这些算法 ,并通过例子说明了它们的可能应用。     

Thermal analysis studies on the boron-potassium perchlorate-nitrocellulose pyrotechnic system

Studies have been carried out on the boron-potassium perchlorate-nitrocellulose pyrotechnic system by DSC, simultaneous TG-DTA-mass spectrometry and chemical analysis. Quantitative measurements have been made on the exothermic pre-ignition reaction which took place above 360°C and the results have been compared with those obtained previously for the corresponding systems containing zirconium and a zirconium/nickel alloy.     

Thrombolytic Agents: Nanocarriers in Targeted Release

A thrombus, known as a blood clot, may form within the vascular system of the body and impede blood flow. Thrombosis is the most common underlying pathology of cardiovascular diseases, contributing to high morbidity and mortality. However, the main thrombolytic drugs (urokinase, streptokinase, etc.) have shortcomings, including a short half-life, serious side effects and a lack of targeting, that limit their clinical application. The use of nano-drug delivery systems is expected to address these problems and a variety of approaches, including biological and physical responsive systems, have been explored. In this report, recent advances in the development of targeted nano-drug delivery systems are thoroughly reviewed.     

基于贝叶斯网的生态工业系统中企业Agent协作关系建模

生态工业系统中的每个企业都可以建模为智能Agent。介绍了一种基于贝叶斯网的方法,对各企业Agent之间的协作关系进行建模。该法能有效表达各企业Agent行为策略之间的因果关系,进而可以对生态工业系统中各企业在不同情况下采取的行为策略进行预测和决策。     

不同底物体系下漆酶的失活动力学研究

本文对三种体系的漆酶热失活动力学进行了研究,并对动力学参数进行了相应的分析。结果显示,漆酶在纯水溶液中的失活符合一级动力学模型,其失活方程为lnA=-0. 1353t-2. 2522。在有毒有机物体系(2,4-二氯酚和吲哚溶液)中漆酶的失活仍符合一级失活动力学模型,失活速率常数减小,但半衰期增大。在极性溶液(乙醇)中,漆酶的反应速率常数最小,可能是因为漆酶分子内部作用力的变化导致了漆酶反应变缓;在非极性体系(异辛烷溶液)中,水-疏水体系减少了对酶的伤害,利于酶的稳定,延长了漆酶半衰期;极性或非极性体系中的漆酶失活均符合一级动力学失活模型。     

四元体系LaCl3-ZnCl2-HCl(7%)-H2O(25℃)和三元体系ZnCl2-HCl-H2O(25℃)相平衡的研究

测定了四元体系LaCl₃-ZnCl₂-HCl(7%)-H₂O(25℃)的稳定平衡的溶度数据，绘制了相应的溶度图。该体系是由5个固相区LaCl₃·7H₂O(原始盐)、3LaCl₃·2ZnCl₂·25H₂O、LaCl₃·2ZnCl₂·11H₂O、2LaCl_{3相似文献}   

Determination of the Rigorous Transfer Function of An Isothermal Titration Microcalorimeter with Peltier Compensation

An old problem in Isothermal Titration Calorimetry is the accurate characterisation of the instrument, i.e. the determination of the instrumental transfer function. Normally, this calibration is performed electrically or through well known chemical reactions, but the transfer function parameters obtained by both methods generally do not agree: the first method normally yields smaller time constants than the second one. This fact is explained by the different path the heat flux takes towards the thermal sink. However, the time constants must be independent of the experiment type (electrical or chemical). In order to attain this independency, a realistic physical model of the system is developed taking into account the different heat sources and the paths in the system and using physically attainable (experimental and theoretical) inputs for testing the model. Important results from the model study are that the instrument is represented by different transfer functions, depending on the heat source location, and that the time constants are the same, regardless of the heat source location. A very simple and fast method based on such non-phenomenological physical model for obtaining the transfer function of an Isothermal Titration Microcalorimeter is applied here.This revised version was published online in November 2005 with corrections to the Cover Date.     

Solvent system selection in counter-current chromatography using conductor-like screening model for real solvents

The aim of this investigation was to minimize the experimental effort for solvent system selection in counter-current chromatography. The separation mechanism in counter-current chromatography is based exclusively on the partitioning of the solute between the two liquid phases. Therefore, a quantum chemical method combined with statistical thermodynamics (conductor-like screening model for real solvents, COSMO-RS) was used for the prediction of the partition coefficient. A comparison of the experimental and predicted data for five model solutes systems demonstrated the potential of the use of COSMO-RS as a screening tool for the solvent system selection.     

Life—a complex polymer system

After a discussion of the different levels of macromolecules, the phenomenon of life is regarded as a complex polymer system. The thermodynamic basis of general system theory is explained as well as the character of system laws. The important notion of emergent system properties is stressed, and life is explained as a system property of a sufficiently complex system. The general applicability of the systemic approach is pointed out, and some examples are provided. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 471–478, 2004     

Analysis of thermally induced solid-solid interactions in vanadia-alumina system

V₂O₅/Al₂O₃ solids of varying compositions were prepared, dried at 100°C and calcined in air at 400–1000°C. The solid-solid interactions between the mixed oxides were investigated by means of DTA, TG and XRD techniques.The results revealed that ammonium metavanadate and aluminium hydroxide decomposed at 260 and 290°C, respectively, to yield an ammonium vanadium intermediate compound and Al₂O₃ as solids. The intermediate compound readily decomposed at 360°C to give V₂O₅.Solid V₂O₅ generally catalyses the crystallization of Al₂O₃ to an extent proportional to its amount present. The solid-solid interactions between Al₂O₃ and V₂O₃ to produce AlV₂O₄ and AlVO₄ took place at 750 and 900°C. These solids decomposed entirely at 1000°C, producing V₂O₅ and alpha-corundum. The pure Al₂O₃ samples employed existed as amorphous solids even when heated in air at 750°C, but in the presence of V₂O₅ (7–18 wt.%) they crystallized to thetaalumina at 600°C. The pure solid alumina crystallized at 1000°C to a mixture of theta and kappa-alumina. In the presence of V₂O₅, alpha-corundum together with kappa and theta phases was obtained on heating at 900°C.