聚丙撑碳酸酯的流动性能

聚丙撑碳酸酯的流动性能王胜杰，黄玉惠，丛广民（中国科学院广州化学研究所广州５１０６５０）关键词聚丙撑碳酸酯，流动性能，表观粘度，粘均分子量聚丙撑碳酸酯（ＰＰＣ）是由二氧化碳和环氧丙烷共聚而成的新型含端羟基脂肪族聚碳酸酯［１］，作为对它的基本表征之一，...     

XPS法测量铝箔表面氧化铝的厚度

介绍了一种无需溅射、无需变角，只需一次简单的ＸＰＳ（Ｘ射线光电子能谱）窄扫描，即可根据谱图中氧化态和金属态的相对强度算出铝金属表面氧化铝的厚度。用该法测量了一系列不同方法处理的铝表面氧比铝厚度，并与椭偏法及ＮＲＡ法（核反应分析法）测定结果进行了对比，结果表明，该法是一种简便准确的膜厚测量法。     

Characterizing the Diffusion and Rheological Properties of Aged Asphalt Binder Rejuvenated with Bio-Oil Based on Molecular Dynamic Simulations and Laboratory Experimentations

Soybean-derived bio-oil is one of the vegetable-based oils that is gaining the most interest for potential use in the rejuvenation of aged asphalt binders. This laboratory study was conducted to characterize and quantify the diffusion and rheological properties of bio-oil-rejuvenated aged asphalt binder (BRAA) using soybean oil. In the study, the chemical structure of the soybean oil was comparatively characterized using an element analyzer (EA), gel permeation chromatography (GPC), and a Fourier infrared (FTIR) spectrometer, respectively. Based on the chemical structure of the bio-oil, BRAA molecular models were built for computing the diffusion parameters using molecular dynamic simulations. Likewise, a dynamic shear rheometer (DSR) test device was used for measuring and quantifying the rheological properties of the aged asphalt binder rejuvenated with 0%, 1%, 2%, 3%, 4%, and 5% soybean oil, respectively. The laboratory test results indicate that bio-oil could potentially improve the diffusion coefficients and phase angle of the aged asphalt binder. Similarly, the corresponding decrease in the complex shear modulus has a positive effect on the low-temperature properties of BRAA. For a bio-oil dosage 4.0%, the diffusion coefficients of the BRAA components are 1.52 × 10⁻⁸, 1.33 × 10⁻⁸, 3.47 × 10⁻⁸, 4.82 × 10⁻⁸ and 3.92 × 10⁻⁸, respectively. Similarly, the corresponding reduction in the complex shear modulus from 1.27 × 10⁷ Pa to 4.0 × 10⁵ Pa suggests an improvement in the low-temperature properties of BRAA. Overall, the study contributes to the literature on the potential use of soybean-derived bio-oil as a rejuvenator of aged asphalt binders.     

A Rheological Model for Evaluating the Behavior of Shear Thickening of Highly Flowable Mortar

Neither the modified Bingham model nor the Herschel–Bulkley model can be used to characterize and calculate the performance of shear thickening of highly flowable mortar because of their incalculability of the rheological parameters. A new exponential rheological model was established to solve the characterization and calculation of shear thickening of the lubrication layer (highly flowable mortar) during the pumping of concrete in this paper. This new exponential rheological model has three rheological parameters, namely, yield stress, consistency coefficient, and consistency exponent. They can quantitatively describe the yield stress, differential viscosity, and shear thickening degree of highly flowable mortar. The calculating results of the rheological parameters of the newly established model for the mortars with different compositions showed that the consistency exponent of mortar decreased with the increase of its sand-binder ratio or the dosage of fly ash in the binder. This indicates that the shear thickening degree of mortar decreases. The consistency exponent of mortar initially decreases and subsequently increases with the increase in silica fume content or the dosage of the superplasticizer. It illustrates that the degree of the shear thickening of mortar initially decreased and subsequently increased. These varying patterns were confirmed by the rheological experiment of mortars.     

原油溶胶-凝胶等温转变过程中的流变性研究

使用RS75流变仪，采用小振幅振荡剪切方法和稳态剪切方法对含蜡原油在溶胶 -凝胶等温转变过程中的流行了研究．结果表明，等温转变成的凝胶原油的结构在 很大程度上决定于预剪切速率，非牛顿含蜡原油在结构恢复过程中表现出不可逆的 触变特性．而凝胶原油在外力作用下向溶胶状态转变的过程中，要经历从线性粘弹 性变形，到非线性粘弹性变形，再到结构屈服的过程，且高剪切应力下的溶胶原油 结构与预剪切速率无关．     

Effect of the Interfacial Agents with Different Types of Hydrophilic Functional Groups on the Rheological Properties of Coal-Water Slurry

Five interfacial agents with different hydrophilic groups (DBS, SDS, SO, TX, CTAB) are used as model additives to prepare coal-water slurry (CWS). The effects of different interfacial agents on the rheological properties of CWS are systemically investigated, the microscopic aggregation behavior of coal particles in the suspensions and the zeta potentials in coal-water interface are also studied. Based on the interpretation of the results, the rheological behavior of CWS is greatly influenced by the adsorption pattern of the interfacial agents in coal-water interface. The adsorption patterns of anionic interfacial agents on coal surface are mainly influenced by the combining force between the anionic hydrophilic groups with Ca²⁺, the stronger combining force with Ca²⁺ leads to the apparent viscosity increase and heavier pseudo-plastic property of CWS. The adsorption pattern of nonionic interfacial agent on coal surface is seldom influenced by the hydrophilic polyoxyethylene chain, and the addition of nonionic interfacial agent reduces the apparent viscosity of CWS. The adsorption pattern of cationic interfacial agent on coal surface is determined by its cationic head, and the addition of cationic interfacial agent increases the apparent viscosity of CWS. The concluded adsorption models of the interfacial agents with different hydrophilic groups can be guidance for the molecular design of high-performance additives of CWS.      

Photoluminescence Properties of Two-dimensional Planar Layer and Three-dimensional Island Layer for ZnO Films Grown Using MOCVD

IntroductionOver the past few years, wide band gap semicon-ductors have attracted considerable attention because oftheir high commercial demand for the preparation ofblue and UV light emitters. The most promising amongall the known materials used for this…     

不同金属缓冲层对GaN薄膜的光学及电学性能的影响

本文以金属Ga和NH₃为原料,Al、Ni和Fe为金属缓冲层,采用化学气相沉积法(CVD)在Si(100)衬底上合成了GaN微米薄膜。利用X射线衍射仪(XRD)、场发射扫描电子显微镜(FESEM)、能量弥散X射线谱(EDS)、光致发光光谱(PL)和霍尔效应测试仪(HMS-3000)等对GaN微米薄膜进行表征。结果表明,所有样品均为六方纤锌矿结构;样品均出现了很强的近带边紫外发射峰和半峰宽较大的中心波长为672nm红光发射峰;不同样品的电学性能差异较大。最后对合成的GaN微米薄膜的可能形成机理进行了简单分析。     

不同金属缓冲层对GaN薄膜的光学及电学性能的影响

本文以金属Ga和NH3为原料,Al、Ni和Fe为金属缓冲层,采用化学气相沉积法(CVD)在Si(100)衬底上合成了GaN微米薄膜。利用X射线衍射仪(XRD)、场发射扫描电子显微镜(FESEM)、能量弥散X射线谱(EDS)、光致发光光谱(PL)和霍尔效应测试仪(HMS-3000)等对GaN微米薄膜进行表征。结果表明,所有样品均为六方纤锌矿结构;样品均出现了很强的近带边紫外发射峰和半峰宽较大的中心波长为672 nm红光发射峰;不同样品的电学性能差异较大。最后对合成的GaN微米薄膜的可能形成机理进行了简单分析。     

Deposition Mechanism and Properties of Plasma-Enhanced Atomic Layer Deposited Gallium Nitride Films with Different Substrate Temperatures

Gallium nitride (GaN) is a wide bandgap semiconductor with remarkable chemical and thermal stability, making it a competitive candidate for a variety of optoelectronic applications. In this study, GaN films are grown using a plasma-enhanced atomic layer deposition (PEALD) with trimethylgallium (TMG) and NH₃ plasma. The effect of substrate temperature on growth mechanism and properties of the PEALD GaN films is systematically studied. The experimental results show that the self-limiting surface chemical reactions occur in the substrate temperature range of 250–350 °C. The substrate temperature strongly affects the crystalline structure, which is nearly amorphous at below 250 °C, with (100) as the major phase at below 400 °C, and (002) dominated at higher temperatures. The X-ray photoelectron spectroscopy spectra reveals the unintentional oxygen incorporation into the films in the forms of Ga₂O₃ and Ga-OH. The amount of Ga-O component decreases, whereas the Ga-Ga component rapidly increases at 400 and 450 °C, due to the decomposition of TMG. The substrate temperature of 350 °C with the highest amount of Ga-N bonds is, therefore, considered the optimum substrate temperature. This study is helpful for improving the quality of PEALD GaN films.     

铝阳极氧化膜阻挡层的去除方法

多孔型铝阳极氧化膜常被用作制备纳米阵列材料的模板,然而阻挡层的存在却在很多方面制约了其应用.为此,已经提出了各种不同的方法来去除阻挡层.本文将这些方法分为2类,即剥离氧化膜去阻挡层和不剥离氧化膜去阻挡层.前者包括化学腐蚀法、干蚀法、电解剥离法;后者包括阶梯降压法、高电流击穿法、电化学法和有多孔铝支撑的化学溶解法.其中,化学腐蚀法和干蚀法的工艺条件已相当成熟,得到了广泛应用,而其它几种方法还多处于实验室研究阶段.由于氧化膜脆性很大,因此,不剥离氧化膜原位去除阻挡层的方法具有更大的实用价值.     

凝胶压井液用阴离子改性胍胶的制备及其流变性能

以环氧氯丙烷和NaHSO_3为原料,Na_2SO_3为引发剂,乙二胺四乙酸二钠(EDTA-2Na)为络合增效剂,经酸催化开环反应合成了磺酸型两性表面活性剂中间体3-氯-2-羟基丙磺酸钠,然后在弱酸性条件下与胍胶通过醚化反应制备了磺酸基羟丙基胍胶,其结构经IR表征。通过正交实验确定了合成配方和条件的最优结果,研究了反应温度、pH、改性胍胶浓度对成胶后凝胶的表观粘度影响,并测试了最佳条件下制备的凝胶和对应稀溶液的流变性能。结果表明:氧氯化锆可有效交联改性胍胶,在pH为6、温度为70℃、改性胍胶浓度为0.6%的条件下制备的凝胶具有剪切变稀性质以及较好的粘弹性。     

用于氨氮检测的薄层氨气微传感芯片及其系统研究

设计并制备了一种具有微池薄液层结构的氨气微传感芯片,并构建了以此微传感芯片为敏感单元的氨氮检测系统,探索了使用安培型氨气微传感器检测氨氮的方法。此微传感芯片采用MEMS工艺制备,通过电化学方法在微电极表面修饰了对氨具有良好电催化氧化性能的纳米铂,提高了传感器的灵敏度。在芯片的SU-8微池中滴入微量碳酸丙烯酯(PC),形成可使氨气迅速扩散到电极表面的薄层电解液,使传感器具有较快的响应速度。使用自行设计的氨氮检测系统对氨氮进行检测,考察了氨氮检测的浓度响应特性、时间响应特性、重复性及选择性。氨氮检测系统的线性范围为0.1～5.0 mg/L;检测下限为0.1 mg/L;响应时间小于1 min;重复性偏差为4.0%。     

Comparative Permeation Study of Different Types of Myoglobin Layer‐by‐Layer Films and the Effect of Film Permeability on Their Electrochemistry and Electrocatalysis

Three different types of myoglobin (Mb) layer‐by‐layer films were assembled respectively with TiO₂ sol‐gel by vapor‐surface deposition, TiO₂ nanoparticles, and poly(styrenesulfonate), designated as {SG‐TiO₂/Mb}_n, {NP‐TiO₂/Mb}_n, and {PSS/Mb}_n. The permeability of the films was studied and compared by rotating disk voltammetry (RDV) and electrochemical impedance spectroscopy (EIS) with different electroactive probes, showing a general permeability sequence of {SG‐TiO₂/Mb}_n>{NP‐TiO₂/Mb}_n>{PSS/Mb}_n. The electrochemical and electrocatalytic activity of Mb in these films were also investigated and compared by cyclic voltammetry (CV), RDV, and amperometry, indicating that among the three Mb films, {SG‐TiO₂/Mb}_n films demonstrated the highest maximum surface concentration of electroactive Mb and the best electrocatalytic performances toward reduction of H₂O₂. All these advantages could be attributed to the unique architecture and porous structure of {SG‐TiO₂/Mb}_n films, which could greatly facilitate the mass transport of small counterions and catalytic substrates within the films. The various influencing factors on the permeability, electrochemistry, and electrocatalysis of the Mb films were also investigated in detail.     

Experimental Investigation of Asphaltenes Flocculation Threshold in Crude Oils Using Different Methods: Comparative Study

Despite some recent progress trustworthy methods to predict the flocculation onset in crude oils are still needed. In this article, different experimental methods, like the density measurement method, the optical and the spot techniques based on the mixture of crude oil + toluene or cyclohexane + n-heptane, respectively, are applied to assess changes of aggregation occurring in crude oil under influence of physical and chemical factors as well as under variable temperature conditions. The solubility parameters of Hildebrand have also been used to predict the flocculation threshold. It turned out that the findings achieved by the spot method and the optical technique are in excellent agreement with break points of the reduced density curves obtained by the density measurement method for crude oils of different geographical origins. Using the solubility parameters of Hildebrand leads to comparable results. All these achievements confirm the density measurement method as a new possibility for reliably determining the flocculation onset in crude oils systems. With respect to temperature effects, changes of the oil microstructure could be detected as function of the temperature by means of the differential scanning calorimetry. In particular the thermal curves behavior of certain crude oils confirmed the existence of aggregation processes.      

溶剂效应计算中两种积分方法的比较研究

采用多面体表面模拟溶质空腔, 讨论了溶剂效应计算中近似积分方法和解析积分方法的平行性和收敛性. 我们发现: 对所研究的40个中性分子, 近似方法和解析方法之间的平行性较好; 但是, 对于20个正离子和27个负离子, 当溶质空腔分别为0.002和0.001 a.u.的等电荷密度面时, 近似方法和解析方法之间的平行性较差, 因此, 近似方法的可靠性不一定有保证. 我们还发现当多面体的表面无限趋近空腔的表面时, 不管采用何种多面体序列, 近似方法和解析方法的基态总能量都基本趋向同一极限值.     

基于不同裂解液的蛋白质组样品制备方法的比较研究

蛋白质组学研究所面临的首要问题就是蛋白质组的样品制备,而不同的样品制备方案针对细胞、组织等样品的裂解能力,以及对不同种类蛋白的溶解能力会有很大的差异.本研究以培养的293T细胞为对象,利用质谱分析鉴定蛋白的方法,比较了采用3种常用的蛋白质组样品制备方法(Triton X-100法、尿素法和TRIzol法)所提取蛋白种类的差异,并利用生物信息学工具对所得数据进行了分析.结果表明,Triton X-100法和尿素法所提取蛋白的鉴定数目接近,而TRIzol法所提取蛋白的鉴定数目比二者减少约8％.从所鉴定的蛋白种类来看,3种方法相差较大,仅约有32％的蛋白为3种方法所共有,生物学功能也不尽相同.本研究为评价各种蛋白质组样品制备方法提供了一种快速、有效、全面的研究方法.     

油脂氧化安定性几种分析方法的比较

主要论述碘值法、过氧化值法、折光率法、电导率法等几种油脂氧化安定性的分析方法在85℃下不同的效果 ,以及电导率法在75℃至120℃的效果。结果表明85℃时的碘值变化不规则 ,过氧化值变化幅度非常小,折光率基本不变 ,而电导率则有一个规律性的明显突变 ,这代表了油脂氧化诱导期的结束 ;进一步对电导率法进行一系列的温度试验,证明当氧化温度不高于90℃时,电导率会产生突变点。若氧化温度高于90℃则电导率无突变 ,且油脂短时间内会有聚合物生成 ,所以,电导率法适用的温度范围是低于90℃。     

Simultaneous Impedance Analysis of Three Parallel Piezoelectric Quartz Crystals for Electrochemical Depletion Layer Effect Study

Simultaneous impedance analysis of three one-face sealed resonating piezoelectric quartz crystals (PQCs) in parallel is proposed through admittance measurements of the three PQCs on one impedance analyzer and then non-linear fitting according to the parallel combination of three Butterworth-Van Dyke circuits. Responses of each PQC obtained from the three-PQC mode agreed well with those measured separately in series sucrose aqueous solutions. This novel method has been used for the study of depletion-layer effect during ferri-/ferrocyanide electrochemical reactions.     

Reversed-Phase High Performance Liquid Chromatographic and Thin Layer Chromatographic Methods for the Simultaneous Determination of Benazepril Hydrochloride and Hydrochlorothiazide in Cibadrex Tablets

ABSTRACT

Two procedures were developed for simultaneous determination of benazepril hydrochloride (I) and hydrochlorothiazide (II) in pure, laboratory made mixtures and in pharmaceutical dosage form “Cibadrex tablets® using reversed phase high performance liquid chromatographic and thin layer chromatographic methods.

For reversed phase HPLC, a new very sensitive, rapid, selective method was developed. The linearity ranges were 32-448 ng/20 μl and 40-560 ng/20 μl for benazepril hydrochloride and hydrochlorothiazide, respectively. The corresponding recoveries were 99.38 ± 1.526 and 99.2 ± 1.123.

The minimum detection limits were 7 ng/20 μl and 14 ng/20 μl for benazepril hydrochloride and hydrochlorothiazide respectively.

On the other hand, a new, simple, sensitive and fast thin layer chromatographic scanning densitometric method was developed for simultaneous determination of benazepril hydrochloride and hydrochlorothiazide using ethyl acetate: methanol: ammonia (85: 20: 10 v/v) as the developing system. The R_f values were 0.33 & 0.68 for benazepril hydrochloride and hydrochlorothiazide respectively. The minimum detection limit obtained was 0.12 μg/spot for benazepril hydrochloride and 0.24 μg/spot for hydrochlorothiazide. The mean percentage recoveries were 100.04 ± 1.102 and 99.31 ± 1.009 for benazepril hydrochloride and hydrochlorothiazide respectively.

The two proposed methods were simple, precise, sensitive and could be successfully applied for the determination of pure, laboratory made mixtures and pharmaceutical dosage forms. The results obtained were compared with those obtained by A ^1%.