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1.
Sulfur is determined in sebacate-base lubricants spectrophotometrically and gravimetrically. In the spectrophotometric method, a 0.2–0.3-g sample is treated with mixed acids, magnesium chloride is added, and the solution is evaporated to dryness. The sulfate is reduced to hydrogen sulfide by treatment with a mixture of hydriodic. hypophosphorous, and hydrochloric acids, and the hydrogen sulfide is distilled into ammonia solution. Lead citrate reagent is added and the brownish yellow color of lead sulfide sol is measured. An improved technique and apparatus for the distillation is described. In the gravimetric method, a 5-g sample is treated with mixed acids, antimony and tin are volatilized by treatment with hydrobromic acid, and sulfur is precipitated as barium sulfate. The recommended range of the spectrophotometric method is 0.005–0.15%,and that of the gravimetric method is 0.01–1% sulfur.  相似文献   

2.
A method is described for measuring free, total, and esterified cholesterol in blood serum in which reversed-phase liquid chromatography is used and the eluate is monitored at 200 nm. The sample for total cholesterol is prepared according to the Abell-Kendall procedure, and for free cholesterol an extract of serum--isopropanol (1:5, v/v) is used. The column is a muBondapak C18, 10 micrometers, and the mobile phase for total cholesterol is isopropanol--acetonitrile (50:50, v/v); for free cholesterol, it is isopropanol--acetonitrile--water (60:30:10). An approximation of the free cholesterol, triglycerides, and individual cholesteryl esters is obtained from single chromatograms of isopropanol extracts of serum if the first mobile phase is used. In a comparison study with the Abell-Kendall method for total cholesterol, the correlation is excellent and the precision is acceptable.  相似文献   

3.
水性聚氨酯的制备及其性能的研究   总被引:15,自引:0,他引:15  
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  相似文献   

4.
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。  相似文献   

5.
Norwitz G  Gordon H 《Talanta》1974,21(7):705-713
An accurate spectrophotometric method is proposed for the determination of pentaerythritol tetranitrate (PETN) in waste water from lead styphnate primer plants by use of phenoldisulphonic acid. The waste water is filtered through a sintered glass crucible and the PETN is determined in the filtrate and the residue. In the determination of PETN in the filtrate, sodium hydroxide is added and the PETN is extracted with methylene chloride (in alkaline solution, styphnate and TNT are not extracted). The methylene chloride solution is then evaporated to dryness, the residue is treated with a solution of phenoldisulphonic acid in sulphuric acid, water and ammonia are added, and the yellow colour is measured. In the determination of PETN in the residue, the PETN is dissolved in acetone, an aliquot of the acetone solution is treated with water and sodium hydroxide, the PETN is extracted with methylene chloride and the colour is developed as above. Various factors affecting the determination were investigated. The solubility of PETN in water was studied.  相似文献   

6.
《印度化学会志》2021,98(11):100194
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.  相似文献   

7.
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.  相似文献   

8.
YCF-1 Mobile irradiator is designed by BINE of China. It has been put into running in YanJi city of Jilin province. It is able to be moved to border and distance places and area lumped and spreading out of agricultural products to service. It can play a important role in demonstration and extending irradiation technology in food irradiation, disinfestation, sterilization and quarantine, etc. This paper describes the features and design considerations of mobile irradiator.This irradiator adopted Cesium-137 source. The design capacity of loading source is 9.25PBq (250kCi), A half-time of Cs- 137 is 30.2 years long, exchanging source is not needed utilization rate of energy is higher, and the shielding is thinner, The Weight is lighter, The dose rate on the surface of it is 0.0025mSv/h in accordance with national standard. The internal size of irradiation room is 1800×1800×900mm (L×W×H), The sheilding of irradiation room is a steel shell filled with lead. The thickness of lead is 18cm. The irradiator is installed on a special flat truck. The size of the truck is 7000×3400×4200mm (L×W×H). The weight of irradiator is more than 80 150kw. The main components and parts of irradiator are: source, source racks and hoist, irradiation chamber, storage source chamber, the product's transport system, dose monitoring system, ventilation system and safety interlock system, etc.  相似文献   

9.
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.  相似文献   

10.
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。  相似文献   

11.
聚苯胺薄膜电极上示差脉冲伏安法可逆波理论研究   总被引:1,自引:1,他引:0  
尹斌  张祖训 《化学学报》1995,53(3):254-262
本文提出了聚苯胺(PANI)薄膜电极上示差脉冲伏安法可逆波理论,经验证理论和实验结果相符合.  相似文献   

12.
The value of preoperative bone scans in patients with primary breast and prostate cancer was evaluated prospectively. Of 414 patients with breast cancer, clinical stage I is 14, II is 219, IIIA is 59, IIIB is 39 and IV is 14. Of 88 patients with prostate cancer, clinical stage I is 14, II is 15, III is 18 and IV is 41. 11 percent of patients with breast cancer and 54 percent of patients with prostate cancer had bone metastases. Clavicle, ribs, thoracic spine, lumbar spine and pelvis metastasized most frequently. The incidences of bone metastases were 18.4% with Scirrhous carcinoma, 15.4% with Medullary tubular carcinoma and 3.8% with Papillotubular carcinoma. The methodology and results of ROC analysis were described in our other papers. Some results of data analysis were described in this paper.  相似文献   

13.
D241树脂分离纯化黄芩总黄酮的研究   总被引:10,自引:1,他引:10  
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%。  相似文献   

14.
The adsorption of linear, branched, and cyclic hydrocarbons in MCM-41 is studied using Configurational Bias Monte Carlo simulations. A new computational model for MCM-41 is proposed which, although simple, is able to predict adsorption isotherms which are in agreement with the scarce experimental data. The structure of the adsorbed phase is analyzed and found to be similar to that of studies using small, hard spheres trapped in pores. The adsorption of mixtures is investigated, and the adsorption hierarchy is discussed. The structure of the adsorbed mixture is revealed and shows that all components of the mixture exhibit structure, even if they are only adsorbed in small quantities. Finally, the model is modified to include surface roughness and the effect on the adsorption isotherms and structure of the adsorbed phase is discussed.  相似文献   

15.
The alkyl polyglycosides (APG) is new type the surfactants that is made by regenerationresource of the starch and the grease, since the nineties of 20th century it is energetically exploited ininternational extent. APG not only good in surface activity, but also plenty on bubble, thin greasyand stabilization, there are good decontamination, compatibility, innocuity, not incitation and uniquefunction that organism decomposition of swiftness and downrightness, and so on.APG is to get production that loses one molecule water with half condensation aldehyde hydroxyand sebum alcohol hydroxy under acid catalysis. The production not is one simplicity compound, butis one of sugar polymerization degree, so it is mixture of the alkyl single glucoside, the alkyl twoglucoside and the alkyl three glucoside.Author synthesizes the surfactants of the alkyl polyglycosides, with the oleaster and potato starchand sebum alcohol, that was chosen to use duality system activator of plant acid and p-toluene-sulfoacid for the first time. The adoption way is that the lower alkyl polyglycosides is firstly formed byreaction of lower alcohol with starch then exchanged with high alcohol to obtain APG. The study isto make certain most technics condition, determining capillary tension and the pastern sheafdeepness of critical, calculating HLB value, determining construction by 1R.To synthesize principium:Peroration :[1]Duality system activator of plant acid and p-toluene-sulfo acid is compare idea activator that was the lower alkyl polyglycosides is firstly formed by reaction of lower alcohol with glucose then exchanged with high alcohol to obtain high alkyl polyglycosides. The advantage is that it overcomes agglomeration, there is reaction entirety, high of sugar transform ratio, reaction time short.[2]Most good reaction temperature is 90~ 170℃, the dosage of activator is 0.5%~0.9%, the mated ratio: The APG of glucose basic butane ratio starch is 5:1, the APG of potato starch basic glycol ratio starch is 6:1, the APG of the oleaster starch basic glycol ratio starch is 12:1, the APG of the mealiest starch basic glycol ratio starch is 6:1, the product of complex is good property.[3]The alkyl polyglycosides is the products of surfactant. IR determines the functional group of the products. On the basis of group of the hydrophile and to close on oil, that the feature peak of α-1, 4- glucoside.[4]The capillary tension of the APG is 26.8~31.0mN/m, the HLB value is 16~18, the products is better emulsifying agent of water- solubility. (O/W).  相似文献   

16.
Recently enhance oil recovery (EOR) technology is getting more attention by many countries since energy crises are getting worse and frightened. One of the reasons for this is due to the shortage of current oil resources and difficulties in finding a new oil field. Indonesia is one of the examples, before 2004 Indonesia is a net oil exporting country but after that Indonesia is a net oil importing country. The oil demand in the country is increasing while the oil production capacity is decreasing. In fact, when a new oil reservoir is drilled, the oil amount obtained from it is about 20-40% of the potential and hence there is still 60-80% oil left in the reservoir. Application of EOR technology gives an additional chance to get out more oil from the reservoir, possibly about another 20%. Polymer is the material that plays an important role in the application of EOR technology, especially surfactant and hydrogel polymers. In the technology, surfactant polymer is injected to the reservoir to reduce an interfacial tension between oil and water and is able to wipe out the trapped oil from the reservoir rock and hence increase the oil production. While an injection of hydrogel polymer to the reservoir is to increase a viscosity of fluid containing water so that the fluid is more difficult to flow than the oil, and as a result, the oil production increases. The most common polymer used for this application is polyacrylamide group.  相似文献   

17.
分子间或分子内的电子激发态能量转移是重要的初级光化学过程,很多体系电子激发态能量转移过程已经报导[1-3],对稀土离子和谈基化合物的研究发现,用光激发配体时,激发了的配体可将能量转移给稀土离子,使稀土离子激发到发光能级,可观察到稀土的特征荧光,若稀土离子和谈基  相似文献   

18.
离心系数表征丙烯酰胺反相乳液的稳定性   总被引:1,自引:0,他引:1  
孟勇  赵飞平  尹笃林 《应用化学》2010,27(10):1133-1137
用丙烯酰胺反相乳液经离心处理后保留的乳液体积与原乳液体积之比(离心系数Vr)考察了丙烯酰胺及其衍生物反相乳液的稳定性。 结果表明,离心系数Vr越大,其乳液的稳定性越好。 在高速离心条件下,由Span80/Span85和Tween80构成的丙烯酰胺及其衍生物反相乳液的Vr与油相质量分数存在正相关的关系。 在油相质量分数确定的情况下,离心系数Vr不仅与3种表面活性剂构成的亲水亲油平衡值(HLB)有关,而且与丙烯酰胺及其衍生物的浓度和类型有关。 HLB值在4.20左右时,乳液是稳定的;随丙烯酸氧乙基三甲基氯化铵(DAC)在水相中质量分数的提高,反相乳液稳定性增强,w(DAC)>24%时可得到稳定乳液。 在15000 r/min离心3 min,Vr=0.95以上的丙烯酰胺及其衍生物反相乳液很稳定,静置半年仍未出现分层现象。  相似文献   

19.
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.  相似文献   

20.
神华煤直接液化残渣热解特性研究   总被引:6,自引:4,他引:2  
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。  相似文献   

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