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| Thesis Name：The combustion of lithium-aluminum alloy fuels in oxygen and water vapor. |
| Country：[CN] |
Usage：[chemistry] |
| Remarks： |
Abstract:
The combustion of a lithium-aluminum alloy was investigated using opticaldiagnostics and a computational flame model. Chemical kinetic mechanisms were developed to modelcombustion of the Li-Al alloy in oxygen and in water vapor. The alloy was heated inductively in acrucible and burned with air, oxygen/argon mixtures, and water vapor in a counterflow diffusionflame. Bulk alloy temperature was held relatively constant during combustion, allowing alloytemperatures in the 1000–1400 K range to be studied. The flame temperature profile wasmeasured using a resonance line reversal method, and the relative lithium atom population in theflame was measured using an absorption method. The products of combustion were collected andanalyzed using x-ray diffraction (XRD) and field-emission scanning electron microscopy/energydispersive x-ray spectroscopy (FESEM/EDS). The primary condensed-phase products of combustion inboth oxygen and water vapor are Li2O, γ-LiAlO2, andβ-Li5AlO4; in addition, some solid LiOH is produced during combustion inwater vapor. Although aluminum monoxide (AlO) gas was detected at ignition in air and water vapor ina limited number of tests, evidence indicates that aluminum does not burn in the vapor phase duringsteady-state combustion of the alloy. Experiments and counterflow diffusion models both show thatthe lithium burns in the vapor phase and aluminum reacts on the surface or in the bulk phase to formγ-LiAlO2, and β-Li 5AlO4. Models indicate thatLi2O is the primary gas-phase product in dry oxidizers and that H2 and LiOHare the primary gas-phase products in water vapor. This work provides the first experimentalevidence that the aluminum in a lithium-aluminum alloy reacts in the liquid phase, the firstchemical kinetic mechanisms to describe lithium vapor-phase flames, and the first chemical kineticmechanisms for combustion of a metal alloy.
Author:Moore, James Thomas.
Unit:The Pennsylvania State University. |
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| Thesis Name：Determination of norfloxacin using an electrochemically pretreated glassy carbon electrode |
| Country：[CN] |
Usage：[electrochemistry] |
| Remarks： |
Abstract The electrochemical behaviors of norfloxacin on a pretreated glassy carbon electrode were investigated by cyclic voltammetry. The results indicated that the process was irreversible and fundamentally controlled by adsorption. The solution conditions and instrumental parameters were investigated and optimized. An optimal curve of norfloxacin was got in 0.1 mol/L phosphate buffer solution of pH 5.29 at 100 mV/s after 2.0 min stirring at 0.3 V. Norfloxacin gave a sensitive adsorptive oxidative peak at 1.17 V (versus Ag-AgCl). The peak current was in linear relation to the norfloxacin concentration in the range of 0.5-5.0 mg/mL. The detection limit was 0.2 mg/mL. This method was used for determination of norfloxacin in capsule，and the RSD was below 2.0 %. Chromatography analysis was also carried out to confirm this method. Statistical analysis of the results using Student t-test and the variance ratio F-test showed no significant difference (p=0.95) between the performance of the two methods as regards to accuracy and precision.
Sun Hanwen, Xing Tao, Lian Kaoqi, Liang Shuxuan
(College of Chemistry and Environmental Science, Hebei University, Key Laboratory of Analytical Science and Technology of Hebei Province, Baoding 071002, China)
Received Apr. 22, 2006; Supported by the Specialized Research Funds of China Education Ministry (No.20050075003) |
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| Thesis Name：Study on spectrofluorimetric determination of sulphides in water |
| Country：[CN] |
Usage：[chemistry] |
| Remarks： |
Abstract A novel spectrofluorimetric determination method of trace amounts of sulphides was described on the basis of Hg (II)-2-(2'-hydroxylphenyl) benzoimidazole (HPBI) fluorescence quenching system. The fluorescence intensity was linear with the concentration of sulphide in the range of 1.0×10-8 - 9.5×10-6 mol/L. The detection limit was down to 9.02×10-9 mol/L. Interferences was avoided by using standard distillation procedure. The main advantages, apart from the extremely high sensitivity of the method, were the high stability of the reacted sulphide system. The method was also applied to measure the trace amounts of sulphides in water sample with satisfactory results.
Zhao Baowei, Jiang Bing, Dong Wenjuan, Zhu Kun
(School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China)
Received Apr. 3, 2006; Supported by the National Natural Science Foundation of China (20577018), and the Qinglan Talent Project of Lanzhou Jiaotong University. |
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| Thesis Name：Progress on modification of carbon nanotubes |
| Country：[CN] |
Usage：[electrochemistry] |
| Remarks： |
Abstract Carbon Nanotubes (CNTs) possess outstanding structural, mechanical, and electronic properties for their unique structure and show great application potential in advanced materials, electronics, and sensing, molecular devices. However, many of these applications are far from us, because of the problems due to their surface disorder and bad dispersion properties. So, more and more researches focus on modification of CNTs. In this article some typical way to modify CNTs will be introduced with a little commons and a preview of this area will be given.
Hao Rui, Zhou Mi, Yuan Jinying
(Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education,Department of Chemistry Tsinghua University, Beijing 100084, China) |
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| Thesis Name：Syntheses and surface analysis of novel poly(dimethylsiloxane) containingamphiphilic graft copolymers. |
| Country：[CN] |
Usage：[chemical industry] |
| Remarks： |
A series of novel amphiphilic graft copolymers consisting of a hydrophilicpoly(2-hydroxyethyl methacrylate) [poly(HEMA)] or poly(2,3-dihydroxypropyl methacrylate)[poly(DHPMA)] backbone and hydrophobic poly(dimethylsiloxane) (PDMS) side chains have beensynthesized. The graft copolymers were prepared via both photoinduced-radical and anionicpolymerization techniques. Using angle-dependent X-ray photoelectron spectroscopy (XPS), the effectsof the PDMS graft length, the PDMS bulk content and the MWD as well as the hydrophilicity of thebackbone on the surface composition of these graft copolymer films were investigated under both dryand wet conditions. It was found that for a given PDMS bulk content, a longer PDMS graft gives asurface richer in siloxane. However, the MWD has little effect on the air (free) surfacecomposition. With increasing PDMS bulk content, the PDMS surface concentration increases forpoly(HEMA-g-DMS) graft copolymers, but no significant difference was observed forpoly(DHPMA-g-DMS)s. As expected, upon exposure to water, the amphiphilic graft copolymers underwenta dramatic surface structure reorganization.; An additional study is reported on evaluation of thepotential of hybrid films to support adhesion and proliferation of primary respiratiory epithelialcell. A series of collagen/PVA hybrid films with different weight percent ratio were prepared. Thesurface composition of these films were investigated by using angular-dependent XPS. The resultsshowed that the PVA component dominated the free surface even for the film with higher ratio ofcollagen component. It was found that with increasing sampling depth, the concentration of collagewithin the surface region slightly increases. The cell culture experiment results showed that thehybrid films supported more robust cell growth than either pure materials.
Author:Hou, Yuanxue.
Units:State University of New York at Buffalo. |
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| Thesis Name：Scope and status of pesticide resistance |
| Country：[CN] |
Usage：[agrochemistry] |
| Remarks： |
The role of pesticide science is to provide society the food, fiber and healththat it requires in an environmentally safe, sustainable and affordable manner. Resistance to thecrop protection products that we use to control insect pests, weeds andplant diseases is a majorproblem we face today in successfully attaining these goals. Growing crops today requires thecombined use of novel crop protection products, transgenic plants and integrated managementtechniques. New chemistry is expensive with the cost of the development, registration and marketingof a single new product estimated at 75-150 million dollar over a period of 8-10 years. Resistanceto our widely used pesticides is common, extensive and increasing. To protect thesusceptibilitywithin targeted populations and our initial research and development investment,pesticide resistance management must be practiced whenever crop protection products are used. Thischapter will summarize our current understanding of resistance to insecticides, herbicides andfungicides and compare their similarities and differences. The current status of resistance, meansto manage resistance and the estimation of resistance "risk" will be discussed for each pesticidegroup.
Author:J. Marshall Clark; Isamu Yamaguchi
Units:Department of Entomology, University of Massachusetts, Amherst, MA 01003 |
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| Thesis Name：The progress in polymeric fullerenes |
| Country：[CN] |
Usage：[chemistry] |
| Remarks： |
Abstract:
Since the discovery and large scale preparation of [60]fullerene, the chemistry of fullerenes has become one of the most developing fields in organic chemistry. Polymeric fullerenes formed by polymerization of the fullerene spheroid possessed unique physical properties, which pioneer one of the new directions for the design of new pattern promising materials based on fullerenes. The progress on the synthesis, magnetic properties and applications of polymeric fullerenes in current years were reviewed. |
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| Thesis Name：Photocatalytic degradation of p-nitrophenol in water with AgCl catalysis |
| Country：[CN] |
Usage：[chemistry] |
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AgCl colloid was obtained by using AgNO3 reacted with NaCl in aqueous solution and then sensitized with UV light illumination. The photocatalytic degradation of p-nitrophenol in aqueous was realized by near UV light or sun light illumination with AgCl catalysis. The degradation kinetics of p-nitrophenol was found to be first-order and the degradation rate coefficient is -0.0337. The degradation rate of p-nitrophenol was increase with increasing of AgCl concentration and decreased with increasing of the initial concentration of p-nitrophenol. It was also found that AgCl was stable during the experiments and can be reused.
Yu Jiemei, Wang Xikui, GuoWeilin, Wang Jingang
(School of Chemistry and Chemical Engineering, Jinan University, Jinan 250022, China) |
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| Thesis Name：Progress in the synthesis of tazobactam and its intermediates |
| Country：[CN] |
Usage：[chemistry] |
| Remarks： |
As a new found b-Lactamase Inhibitor, Tazobactam has an outstanding effect in terms of the inhibition ofb-Lactamase. This paper summarized the progress in the synthesis of tazobactam and its intermediates around the world，and it also compares the different methods in the synthetic process.
Zhang Kainan, Li Yunzheng, Zhang Qingshan, Guo Bingnan
(School of Chemical Engineering and Environment，Beijing Institute of Technology, Beijing, 100081) |
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| Thesis Name：Evaluation of adsorptive properties of mesoporous materials by sorption fibers |
| Country：[CN] |
Usage：[chemistry] |
| Remarks： |
Du Xinzhen1,2, Tao Xiaojuan, Wang Yarong1, Ding Ning1, Chen Hui1
(1 Department of Chemistry, Northwest Normal University, Lanzhou 730070; 2 The Key Laboratory of Polymer Materials of Gansu Province, Lanzhou 730070, China)
Received Mar.10, 2006;Supported by the National Natural Science Foundation of China (No: 20575053), the Natural Science Foundation of Gansu Province (3ZS051-A25-011-022) and the Key Laboratory of Polymer Materials of Gansu Province.
Abstract:
Mesoporous silica and composite were used as fiber coatings to evaluate their adsorptive properties. A diffusion-controlled process was involved for the adsorption of toluene, p-xylene, biphenyl and anthracene onto mesoporous materials in water matrix. Vigorous stirring and heating of the solution are favorable for the diffusion of the studied compounds. The fiber coated with phenyl-MCM-41 shows high adsorption efficiency and good molecular recognition but negative effect of salt on adsorption of target compounds. Rapid desorption could be obtained in aqueous solution containing methanol. The fiber is easy to prepare and handle. Moreover, only a small quantity of adsorption material was needed to prepare the sorption fibers compared with conventional batch sorption experiments. The fibers are inexpensive, durable and easy to couple with HPLC. Quantitative adsorption and desorption was obtained with good reproducibility. The coated fibers offer an alternative way to evaluate the adsorption behavior of potential adsorption or separation materials. |
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