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991.
Varun Sahni 《Pramana》1998,51(1-2):27-37
992.
Dilute aqueous solutions of dodecyl-benzenesulfonic acid sodium salt (DBS-Na) and polyoxyethylenenonylphenyl ethers (PONPEs) were ultrasonically atomized. The surfactants were concentrated in collected mist droplets. The enrichment ratio increased with decreasing surfactant concentration. Depending on the surfactant’s molecular weight and affinity to water, different enrichment ratio was observed in the range of low feed concentrations. For anionic surfactant, DBS-Na, the enrichment ratio was significantly improved by KCl addition and a peak appeared on the plot of the ratio against KCl concentration. Addition of NaCl or CaCl2 · 2H2O to the surfactant solution also enhanced the enrichment ratio; however, the effect was relatively small. Such behaviors of the ratio were interpreted as enhanced interfacial adsorption of the surfactant and a lack of supply of surfactant monomers from liquid bulk because of slow breaking of surfactant micelles. Time required for collecting an amount of mist was also observed. Among the three salt systems, the time for KCl system was twice as long as others. This fact suggested that the formation of smaller droplets in KCl system. 相似文献
993.
M. V. Pryadeina Ya. V. Burgart M. I. Kodess V. I. Saloutin 《Russian Chemical Bulletin》2005,54(12):2841-2845
Cyclocondensation of 2-arylmethylidene-3-fluoroalkyl-oxopropionates with 2-amino-pyridine occurs at both the polyfluoroacylvinyl
and alkoxycarbonylvinyl fragments to give alkyl 4-aryl-2-polyfluoroalkyl-4H-pyrido[1,2-a]pyrimidine-3-carboxylates and 4-aryl-2-hydroxy-3-polyfluoroacyl-4H-pyrido[1,2-a]pyrimidines, respectively. When treated with copper(II) acetate, the pyrido[1,2-a]pyrimidines yield metal complexes.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2745–2749, December, 2005. 相似文献
994.
995.
A mathematical model describing interfacial radical polymerization‐based film formation on hydrogels is elucidated. A glucose oxidase‐mediated multistage initiation reaction is used to accomplish interfacial film formation. A polymer concentration‐dependent diffusion coefficient is used to reflect the changing mass transport conditions as the film develops. Model predictions of the film thickness as a function of the species concentrations agree well with experiments. The model predicts that the degree of initiation reaction delocalization with the enzyme‐mediated initiation system is significantly higher than an enzyme‐independent system, thus affecting the film growth rate and structure. The mass transport properties of the film and its adhesion to the underlying substrate are also investigated.
996.
《Journal of Energy Chemistry》2014,23(5):633-638
MgO-modified Ni/Al2O3 catalysts with different Ni loadings were prepared and employed in dry reforming of methane (DRM). The effect of Ni loadings on the activity and coke formation of Ni/MgO-Al2O3 catalysts were investigated. The synthesized catalysts were characterized by XRD, N2 adsorption-desorption, SEM, TPO and TPR techniques. The obtained results showed that increasing nickel loading decreased the BET surface area and increased the catalytic activity and amount of deposited carbon. In addition, the effect of gas hourly space velocity (GHSV) and feed ratio were studied. 相似文献
997.
本实验以钛酸四丁酯为钛源,醋酸镉为镉源,利用静电纺丝的方法制备了直径~250 nm的电纺丝纳米纤维。通过高温煅烧和硫化钠溶液进行水热处理,得到CdS超薄片层包覆TiO2中空结构的纳米纤维。推测该复合结构形貌的形成过程为:在Ti/Cd(摩尔比)为1:1和2:1时,由于CdO的含量较高,反应过程中CdO溶解,并与反应溶液中的S2-形成CdS超薄片层生长在纤维的外表面,剩余的TiO2纳米粒子聚集形成中空的纳米管状结构;而Ti/Cd(摩尔比)为4:1和8:1时,由于溶解的CdO较少不足以形成TiO2纳米管,同时,生成的CdS也不足以完全包覆TiO2纳米纤维形成非管状结构。当Ti/Cd为1:1时,TiO2@CdS复合材料具有最好的产氢活性。在300 W氙灯光照条件下和加UVCUT-420 nm滤光片下,50 mg催化剂产氢速率分别为19.7 μmol/h和3.4 μmol/h,这主要是由于所得到的复合结构中TiO2为非晶材料。进一步在惰性气氛下煅烧,也很难将TiO2晶化。 相似文献
998.
Using an on-line solution-reaction isoperibol calorimeter, the standard molar enthalpies of reaction for the general thermochemical reaction: LnCl3·6H2O(s) + 2C9H7NO(s) + CH3COONa(s) = Ln(C9H6NO)2(C2H3O2)(s) + NaCl(s) + 2HCl(g) + 6H2O(l) (Ln: Nd, Sm), were determined at T=298.15 K, as kJ mol−l, respectively. From the mentioned standard molar enthalpies of reaction and other auxiliary thermodynamic quantities, the standard molar enthalpies of formation of Ln(C9H6NO)2(C2H3O2)(s) (Ln: Nd, Sm), at T=298.15 K, have been derived to be: −(1494.7±3.3) and −(1501.5±3.4) kJ mol−l, respectively. 相似文献
999.
协调政府与社会资本合作的利益分歧,进而实现个体理性向集体理性的趋同,这是纾解PPP项目合作困境的切入点之一。基于合作博弈理论,本文构建PPP项目非完全利益群体的合作形成机制,分析政府与社会资本间“合作共赢”的必要因素。研究表明,由政府与社会资本组成的PPP项目非完全利益群体,可在“理性-效用转移-有效协商”机制的协同作用下主动采取最优合作策略。其中,理性机制验证了政府与社会资本达成合作意向的前提,效用转移机制可实现二者之间的风险-收益对等,有效协商机制将达成政府与社会资本合作的帕累托均衡。 相似文献
1000.
David M. Ramsey 《European Journal of Operational Research》2012,216(3):624-637
A model of partnership formation based on two traits, called beauty and character, is presented. There are two classes of individual and partners must be of different classes. Individuals prefer prospective partners with a high beauty measure and of a similar character. This problem may be interpreted as e.g. a job search problem in which the classes are employer and employee, or a mate choice problem in which the classes are male and female. Beauty can be observed instantly. However, a costly date (or interview) is required to observe the character of a prospective partner. On observing the beauty of a prospective partner, an individual decides whether he/she wishes to date. During a date, the participants observe each other’s character and then decide whether to form a pair. Mutual acceptance is required both for a date to occur and pair formation. On finding a partner, an individual stops searching. Beauty has a continuous distribution on a finite interval, while character ‘forms a circle’ and has a uniform distribution. Criteria based on the concept of a subgame perfect Nash equilibrium are used to define a symmetric equilibrium of this game. It is argued that this equilibrium is unique. When dating costs are high, this equilibrium is a block separating equilibrium as in more classical formulations of two-sided job search problems. However, for sufficiently small dating costs the form of this equilibrium is essentially different. 相似文献