N,O-羧甲基壳聚糖的合成和性质研究

采用多段升温法将壳聚糖改性,合成了取代度为1.84、平均分子量为3.08×105、等电点为7.28的N,O-羧甲基壳聚糖(CMC),分别用紫外光谱、红外光谱、荧光光谱对其结构进行了表征,并对其水溶液的Zeta电位、电导率、表面张力以及水分散体系中羧甲基壳聚糖微粒的粒径分布进行了研究.结果表明, N,O-羧甲基壳聚糖具有表面活性;介质的pH值和浓度对羧甲基壳聚糖溶液的稳定性有很大的影响.     

山东省主栽果树生殖器官中稀土与微量营养元素的相关性研究

通过对山东省5大类主栽果树20余个树种的花粉、种子和果实稀土与微量元素自然含量进行分析比较, 认为稀土(RE)与微量元素在各树种花粉中平均含量顺序为Fe＞Zn＞B＞Cu＞Mn＞RE, 种子中B＞Fe＞Zn＞Mn＞Cu＞RE, 果实中Fe＞B＞Zn＞Cu＞Mn＞RE. 各元素在各生殖器官中的自然分布因树种而有很大差异. 但基本规律类同, 即花粉＞种子＞果实. 花粉富集各种微量营养元素的能力都很强. 花粉和果实稀土与微量元素之间绝大多数呈正相关, 种子大多呈负相关, 但相关性均不显著.     

水性聚氨酯的制备及其性能的研究

本文以琥珀酸酐与三羟甲基丙烷反应,制得了含有羟基和羧基的酯类亲水性单体,并以此单体与ＴＤＩ和ＰＰＧ－１０００反应,制得了含有羧基的聚氨酯预聚体,在三乙醇胺水溶液中分散得到了水性聚氨酯（简称ＷＰＵ）。本文对预聚体的溶剂种类和用量,对乳胶粒的大小及形状的影响进行了研究,确认溶剂的用量越大,乳胶的粒径就越小;以丙酮作溶剂,乳胶粒为棒状或橄榄球状,而以丁酮为溶剂,得到的乳胶粒为圆球状。通过改变亲水单体的用     

用计算全息法检测卡塞格林系统主镜

为实现对卡塞格林光学系统中的非球面主镜表面面形的高精度检测,设计了一种二元位相型计算全息图(CGH)。介绍了工作原理,对CGH的相位模型参数的优化设计、衍射次级分离以及台阶位置与深度计算等关键问题进行了讨论。通过引入虚拟玻璃的概念快速建立非球面检测模型,针对卡塞格林系统主镜中心开孔的特点,通过加入同轴载波实现了衍射次级的完全分离,相比目前常用的倾斜载波方法简化了相位量化复杂度,数值仿真计算出了最优的台阶深度,降低了加工难度。给出了相应的设计方法及实例,研制投产了CGH。测试得到主镜面形的均方根误差为0.018λ,并与传统补偿器结果(RMS=0.019λ)进行对比,两者测试结果吻合,验证了该设计与检测方法的正确性,该设计方法简单快捷,适用于卡塞格林光学系统主镜面形检测。     

尿激酶活性测定方法的比较

根据中国及日本药典,对测定尿激酶活性的两种方法的灵敏度和重复性进行了考察对比,对不同样品测定结果进行了比较。     

Wastewater treatment using nanomaterial quaternary photocatalyst ZrCdPbO4 - Removal of colour pollutant by an eco friendly process

Pollution of environment is a major issue and has drawn attention of researchers throughout the globe. Water is polluted by various means like excretion of various industries and house releases, for example release of yarn, paper, and cloth industries etc. Present investigation consists of removal of such a pollutant. For this, synthesis of a novel quaternary nano particle sized photocatalyst ZrCdPbO₄ is carried and its characterization by different analytical techniques is also carried out. This is further used for removal of colour pollutants from the environment and Erythrosine-B is considered as a role model. Effect of various operational parameters like pH, concentration of dye, amount of photocatalyst, irradiation power etc. is studied, maximum degradation condition is extracted, and it is observed that reaction follows pseudo first order kinetics. Scavenger study suggests the participation of OH free radical in the reaction. Complete degradation of the dye in presence of light and photocatalyst is reported here by. Reusability of the photocatalyst is tested and is found to work up to five cycles efficiently.     

Precolumn,Capillary Column,Electron Capture G-AS Chromatography For High Efficiency Trace Determination

Abstract

A method for gas chromatographic trace determination is described in which the sample solution is injected into a packed precolumn which is connected to an EC-detector. When solvent and low boiling compounds have been eluted, the precolumn is connected to the cold entry of a capillary column with another EC-detector and the trace compound is collected as a narrow band at the entry of this column. The precolumn is then reconnected to its own detector, the capillary column is heated and the trace compound is eluted and measured. Meanwhile high boiling compounds are swept out of the precolumn. When the base line of the precolumn is stable the next sample is injected and the capillary column is cooled again, and so on. In order to avoid background plateaus and ghost peaks the carrier gas must be purified, which is easily achieved with cooling traps with dry-ice and acetone.     

改进的Herriott型光学长程池

用凹面反射镜和平面反射镜组成结构简单、光路易调的光多次反射装置,计算了这种光学系统的稳定性条件。考虑实际入射光束的直径和发散角,给出了最大反射次数的求法。制成适用于钛宝石激光光声光谱仪的光56次通过的长程池。理论计算的反射光斑分布与实验观测一致。这个技术有利于提高光声光谱和吸收光谱的探测灵敏度。     

流动注射分光光度法测定矿物浸提液中的游离氰化物

在氢氧化钠介质中游离的氰化物与苦味酸钠反应生成玫瑰红酸钠，并进行升温改善反应条件。双流路系统与单流路相比，峰形规范、光滑，能有效消除鬼峰，优化了显色条件，工作波长为５１０ｎｍ。按生产工艺要求的线性范围为４．０￣４０．０ｍｍｏｌ／Ｌ。进样频率为１３０次／ｈ。已成功地用于矿物浸提液中游离氰化物的现场分析。     

D241树脂分离纯化黄芩总黄酮的研究

本文研究了用241树脂分离纯化黄芩总黄酮的方法和工艺。实验结果表明：D241树脂对黄芩总黄酮的静态交换容量是77mg/ml树脂。在pH11.0、流速2.0BV/h、提取液中总黄酮浓度17.5mg/ml条件下，D241树脂对黄芩总黄酮的动态交换容量为43.8mg/ml。用60％甲醇作为黄芩总黄酮洗脱剂，在PH4.0、洗脱流速1.5BV/h条件下，4．5BV洗脱剂即可完全洗脱被D241树脂交换的黄芩总黄酮。与酸沉淀法相比较，经过除去果胶，总黄酮纯度由33．34％提高到74．9％，粗品收得率由11.52%降低至4.83%；经过D241树脂分离纯化，其纯度达到91.5%，产品收得率3.54%。     

微波消解-ICP-MS测定电镀污泥中的重金属

采用微波消解系统对某电镀污泥进行消解,利用ICP-MS对污泥中的重金属进行测定。称取制备后样品,置于消解罐中充分反应后,赶酸、定容后利用电感耦合等离子体质谱法进行测定。电镀污泥中的铬为18845.2mg/kg、镉为10.3mg/kg、镍为5200.0mg/kg、铅为189.7mg/kg、铜为3271.7mg/kg、锌为49632.6mg/kg。测定结果表明所检测项目工作曲线线性关系好,相关系数r均大于0.999。铬加标回收率在91.6～97.7%之间、镉加标回收率在92.0～97.0%之间、镍加标回收率在95.1～98.0%之间、铅加标回收率在94.3～95.2%之间、铜加标回收率在97.1～102%之间、锌加标回收率在96.3～98.7%之间,均满足相关测定要求。计算的潜在生态危害系数、潜在生态危害指数结果表明,电镀污泥中的铬、镉、铅、铜、锌为轻微生态危害,镍为强生态危害;潜在生态危害指数RI计算值为216.69,属于中等生态危害。     

神华煤直接液化残渣热解特性研究

通过热重分析技术考察了神华煤直接液化残渣的热解特性。结果表明,和煤热解相比,在相同条件下残渣热解具有更大的失重率和失重速率。残渣热失重分为三个阶段,在173℃以前为残渣热解第一阶段;从173℃～510℃是残渣热解第二阶段,此阶段为残渣的主要失重阶段;510℃以后是残渣热解的第三阶段,在这个阶段残渣继续失重,此阶段的失重是由于残渣的二次分解和残渣中的矿物质分解造成的。通过比较脱油前后残渣热失重曲线发现,残渣主要失重是由于残渣中重质油、沥青烯以及前沥青烯的热解以及挥发造成的。通过脱灰残渣的热解发现,与原残渣相比,脱灰后残渣的失重量变小,矿物质的分解和残渣中有机组分的缩聚是温度高于649℃以后残渣失重的主要原因。由热解特征参数看出,脱油残渣的初始热解温度、最大失重温度以及剧烈热解终温均高于原煤,说明和原煤相比,脱油后残渣中惰性组分不易热解。与原煤和四氢呋喃脱油渣相比,残渣具有最大的失重速率,这是由于残渣中含有大量重质油、沥青烯以及前沥青烯造成的。     

利用13C探头测27Al核磁共振谱

对于８０ＭＨＺ的核磁共振仪，＾１３Ｃ与＾２７Ａｌ的共振频率差为０．７３８ＭＨＺ。由于＾１３Ｃ核磁共振谱测定时需要较宽的频带，选择合适的参数，用＾１３Ｃ１０ｎｍ单探头或６１３Ｃ－＾１Ｈ５ｍｍ双探头都可以测得＾２７Ａｌ核磁共振谱。当Ａｌ＾３＋＝０．１ｍｏｌ／Ｌ时，对于＾１３Ｃ１０ｍｍ探头灵敏度为４２，线宽４。８ＨＺ；对＾１３Ｃ－Ｈ５ｍｍ双探头，灵敏度为２４．８，线宽为３．２ＨＺ。     

On-line water removal during enzymatic triacylglycerol synthesis by means of pervaporation

Triacylglycerols can be synthesized from glycerol and fatty acids. During this equilibrium reaction water is produced, therefore a mixture of mono-, di- and triesters is obtained. One way to produce an excess of triacylglycerols is to remove the water produced during synthesis. This can be realized in an immobilized enzyme pervaporation system. The enzyme is immobilized onto the lumen side of a cellulose membrane where the organic phase is present. Air circulates at the shell side and the water activity is controlled with the use of a condenser. The lipase catalyzed esterification of decanoic acid and partial glycerides is studied in this reactor. The system is reaction limited. Only at low water activity conditions, an excess of triacylglycerols is obtained. The enzyme activity at the start of the experiments is independent of the water activity within the range studied. Stability is influenced: After 600 hours the activity is 26% of the activity at the start at a_w = 0.1 and 71% at a_w = 0.45.     

原子吸收光谱法间接测定萤石中的全硫

基于SO42-和BaCrO4溶液反应生成BaSO4沉淀, 置换出定量的CrO42-, 通过原子吸收法测定Cr, 建立了间接测定萤石中硫的原子吸收光谱法. 方法的工作曲线范围0.05～20 μg/mL SO42-, 检出限为0.017 μg/mL S, 适用于硫质量分数在0.01%～3%范围内萤石样品的测定.     

广州地区健康儿童及成人发硒含量调查

测定了广州地区52名健康儿童及72名健康成人的发硒含量。儿童平均年龄6.4±3.3岁,儿童男性发硒含量为(0.44±0.14)×10-6,女性为(0.40±0.15)×10-6。成人平均年龄53.3±14.7岁,成人男性发硒含量为(0.49±0.12)×10-6,女性为(0.51±0.12)×10-6。儿童及成人发硒含量男女之间不存在显著性差异,男性儿童与男性成人发硒含量不存在显著性差异,但女性儿童发硒含量显著低于女性成年人。     

氟吗啉合成工艺热危险性及动力学研究

氟吗啉是一种新型杀菌剂, 合成工艺热危险性和动力学研究将解决工程问题, 并保障安全生产. 采用差示扫描量热-热重分析仪(DSC-TG)测试主要原料、中间体和产品的热稳定性, 采用反应量热仪(RC1)研究反应热行为, 同时开展反应动力学研究. 研究结果显示, 主要中间体(3,4-二甲氧基苯基)(4-氟苯基)甲酮吸热分解温度为559.3 K, 乙酰吗啉吸热分解温度为478.2 K, 氟吗啉吸热分解温度为638.6 K. 氟吗啉合成反应摩尔放热量为15.44 kJ/mol, 绝热温升ΔT_ad为9.1 K, 本研究合成工艺的热危险性较小. 氟吗啉合成反应动力学方程为：r_A=kc_A^a=8.34×10^-3C_A^0.57, 对主要中间体(3,4-二甲氧基苯基)(4-氟苯基)甲酮的反应级数为0.57 级.     

Facile Electrochemical Hydrogenation and Chlorination of Glassy Carbon to Produce Highly Reactive and Uniform Surfaces for Stable Anchoring of Thiolated Molecules

Carbon is a highly adaptable family of materials and is one of the most chemically stable materials known, providing a remarkable platform for the development of tunable molecular interfaces. Herein, we report a two‐step process for the electrochemical hydrogenation of glassy carbon followed by either chemical or electrochemical chlorination to provide a highly reactive surface for further functionalization. The carbon surface at each stage of the process is characterized by AFM, SEM, Raman, attenuated total reflectance (ATR) FTIR, X‐ray photoelectron spectroscopy (XPS), and electroanalytical techniques. Electrochemical chlorination of hydrogen‐terminated surfaces is achieved in just 5 min at room temperature with hydrochloric acid, and chemical chlorination is performed with phosphorus pentachloride at 50 °C over a three‐hour period. A more controlled and uniform surface is obtained using the electrochemical approach, as chemical chlorination is observed to damage the glassy carbon surface. A ferrocene‐labeled alkylthiol is used as a model system to demonstrate the genericity and potential application of the highly reactive chlorinated surface formed, and the methodology is optimized. This process is then applied to thiolated DNA, and the functionality of the immobilized DNA probe is demonstrated. XPS reveals the covalent bond formed to be a C?S bond. The thermal stability of the thiolated molecules anchored on the glassy carbon is evaluated, and is found to be far superior to that on gold surfaces. This is the first report on the electrochemical hydrogenation and electrochemical chlorination of a glassy carbon surface, and this facile process can be applied to the highly stable functionalization of carbon surfaces with a plethora of diverse molecules, finding widespread applications.     

多元统计描述中随机误差与变量空间角的关系

多元分析的误差传递需要一种简单、准确、数值化的表达方法.向量空间中,线性多元混合信号的随机误差可表述成真值子空间中随机向量的表现;由体系多元变量对应的向量构成的真值子空间中,被关注向量和其他向量子空间的空间角θ是描述多元体系的重要参数.如果被关注向量和其他向量子空间关系确定,体系总体误差呈正态分布,那么,被关注向量上误差也是正态分布,其多元统计分析结果的标准差与体系误差标准差的比值为1/(2·sin(θ/2),结论在构造算例和邻、间、对苯二酚混合体系的紫外光度分析中得到验证.     

Staircase voltammetry with finite diffusion space

A theory of the staircase voltammetry in a thin-layer cell is developed. The influence of the cell thickness and the redox reaction rate constant on the current and the peak potentials is analyzed. For moderately thick cells, the kinetic maximum is predicted. The relationship between peak currents and the square root of the scan rate is not linear and the response may entirely vanish if the redox reaction is fast, the cell is very thin and the scan rate is slow.