纳米铁的低温热容和热力学性质研究

用扫描电子显微镜(SEM)测定了纳米铁试样的粒径, SEM结果表明Fe试样平均粒径d为25 nm. 在84～350 K温区, 用精密低温绝热量热计测定了该纳米铁试样的等压摩尔热容, 拟合出其等压摩尔热容与热力学温度的函数关系式: Cp=36.831+14.772x−5.4968x2−0.7099x3−1.3188x4, 其中x=(T−234)/156. 根据热容与热力学函数关系, 计算了以298.15 K为基准的纳米Fe(d=25 nm)热力学函数, 并与文献报导的粗晶Fe及粒径87 nm Fe的热容进行了比较, 从能量角度分析了不同粒径Fe热容曲线差别产生的原因.     

Ag/SBA-15低温气相选择性催化氧化苯甲醇合成苯甲醛

以SBA-15为载体,采用浸渍法制备了不同Ag含量的Ag/SBA-15,通过N₂吸附-脱附、X射线衍射、扫描电子显微镜、高分辨透射电子显微镜、X射线光电子能谱和电感耦合等离子体质谱对催化剂进行了表征。将Ag/SBA-15用于苯甲醇气相选择性催化氧化合成苯甲醛,研究了反应条件对转化率和选择性的影响。结果表明,Ag/SBA-15具有均一的一维孔道结构、较厚的孔壁（3-5 nm）及较大的比表面积（411-541 m²/g）,其规整纳米空间的限域作用使一定负载量的Ag以纳米尺寸均匀分散于介孔SBA-15孔道内,增加了活性组分的比表面积。亲核性氧物种从Ag到SBA-15表面的氧溢流,提高了低温下Ag/SBA-15对苯甲醇气相选择性氧化合成苯甲醛的催化性能。5.3% Ag/SBA-15中的Ag粒径为5-6 nm,且均匀分散于载体孔道中,反应温度为220℃时,苯甲醇转化率为87%,苯甲醛选择性为95%;240℃时,苯甲醇转化率和苯甲醛选择性分别高达94%和97%;并在240-300℃范围内,其催化活性和选择性保持不变,表现出了良好的温度耐受能力。催化剂经活化再生可以连续使用40 h,选择性基本保持不变。     

硫化态Mo/γ-Al2O3催化剂活性位的低温CO-FTIR方法表征及噻吩HDS活性

ＭｏＳ2 是钼基加氢精制催化剂 [Ｃｏ(Ｎｉ)Ｍｏ/γ Ａｌ2 Ｏ3]活性相的主要组份 ,其形态与结构对Ｃｏ(Ｎｉ)Ｍｏ/γ Ａｌ2 Ｏ3的加氢脱硫 (ＨＤＳ)、加氢脱氮 (ＨＤＮ)活性的影响至关重要[1 ,2 ] .目前 ,人们通常使用的ＴＰＲ方法虽可测定过渡金属硫化物的表面活性位 ,并可有效地区分位于催化剂活性相 (ＭｏＳ2 ｓｌａｂ)周边的硫物种 ,但对不同价态的钼尚无法鉴别[3] .本文制备了硫化态Ｍｏ/γ Ａｌ2 Ｏ3催化剂 ,以ＣＯ为探针分子 ,利用ＦＴＩＲ技术在液氮温度 (77Ｋ)下考察了催化剂的表面活性位 (钼物种 )及催化噻吩ＨＤＳ的活性 .1　实…     

Low Temperature Heat Capacities and Thermodynamic Properties of Zinc L-Threonate Zn（C4H7O5）2（s） by Adiabatic Calorimetry

Low-temperature heat capacities of the solid compound Zn（C4H7O5）2（s） were measured in a temperature range from 78 to 374 K, with an automated adiabatic calorimeter. A solid-to-solid phase transition occurred in the temperature range of 295？322 K. The peak temperature, the enthalpy, and entropy of the phase transition were determined to be （316.269±1.039） K, （11.194±0.335） kJ？mol-1, and （35.391±0.654） J？K-1？mol-1, respectively. The experimental values of the molar heat capacities in the temperature regions of 78？295 K and 322？374 K were fitted to two polynomial equations of heat capacities（Cp,m） with reduced temperatures（X） and [X = f（T）], with the help of the least squares method, respectively. The smoothed molar heat capacities and thermodynamic functions of the compound, relative to that of the standard reference temperature 293.15 K, were calculated on the basis of the fitted polynomials and tabulated with an interval of 5 K. In addition, the possible mechanism of thermal decomposition of the compound was inferred by the result of TG-DTG analysis.     

t-ZrO2/α-Al2O3超细晶复合粉体的低温燃烧合成

以Al(NO3)3*9H2O、ZrO(NO3)2*2H2O和Y(NO3)3*6H2O为原料,采用低温燃烧合成(LCS)法制备了多种不同ZrO2/Al2O3比的复合粉体,对其物相和形貌进行了表征.实验结果表明,采用LCS法在400℃合成的t-ZrO2/α-Al2O3复合粉体晶粒超细,其结晶程度随ZrO2/Al2O3比的增加逐渐降低,晶粒大小也随ZrO2/Al2O3比的变化而有规律地变化.     

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基于介质阻挡放电(DBD)原理,研究设计了一种悬浮电极式的低温等离子体发生设备,产生的等离子体温度较低且对人体安全,可直接接触。用所研制的低温等离子体发生设备对大肠杆菌做了灭活实验,实验结果表明,该设备产生的低温等离子体对大肠杆菌作用10s 以上,在等离子体有效作用区内大肠杆菌杀灭率为100%,表明所研制的低温等离子体发生设备具有很好的杀菌消毒效果。     

Exploitation of phosphorescent labelling reagent of fullerol-fluorescein isothiocyanate and new method for the determination of trace alkaline phosphatase as well as forecast of human diseases

A new phosphorescent labelling reagent consisting of fullerol, fluorescein isothiocyanate and N,N-dimethylaniline (F-ol-(FITC)_n-DMA) was developed. The mode of action is based on the reactivity of the active -OH group in F-ol with the -COOH group of FITC to form an F-ol-(FITC)_n-DMA complex containing several FITC molecules. F-ol-(FITC)_n-DMA increased the number of luminescent molecules in the biological target of WGA-AP-WGA-F-ol-(FITC)_n-DMA (WGA and AP are wheat germ agglutinin and alkaline phosphatase, respectively) which improved the sensitivity using solid substrate room temperature phosphorimetry (SSRTP) detection. The proposed method provided high sensitivity and strong specificity for WGA-AP. The limit of detection (LD) was 0.15 ag AP spot⁻¹ for F-ol and 0.097 ag AP spot⁻¹ for FITC in F-ol-(FITC)_n-DMA, which was lower than the method using single luminescent molecules of F-ol-DMA and FITC-DMA to label WGA (0.20 ag AP spot⁻¹ for F-ol-DMA and 0.22 ag AP spot⁻¹ for FITC-DMA). Results for the determination of AP in human serum were in good agreement with those obtained by enzyme-linked immunosorbent assay. The mechanism of F-ol-(FITC)_n-DMA labelling of WGA was discussed.     

Selective Determination of Hafnium with Solid Surface Room Temperature Phosphorescence Optosensing

Abstract

An optosensing method for selective determination of hafnium has be developed. It is based on the phenomenon that when the complex formed by 8-hydroxy-5-quinolinesulfonic acid with hafnium is absorbed on the strongly basic anion exchange resin, the phosphor can produce room temperature phosphora-scence (RTP) in aqueous medium. The hafnium can be determined selectively in the presence of zirconium. The RTP intensity is linear up to 4×10^-5 M of hafnium, the detection limit is found to be 5×10^-8 M of hafnium.     

中草药有效成分山姜素的固体表面室温磷光法研究

本文选择滤纸作基质，以ＬｉＡｃ作重原子微扰剂，建立了测定中草药中痕量有效成分山姜素的滤纸表面室温磷光法。该法取样量少（２μＬ），线性范围宽（２．９～５８０ｎｇ／斑），灵敏度高（检出限０．４０ｎｇ／斑），操作简便、快速。