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排序方式: 共有10000条查询结果,搜索用时 213 毫秒
971.
L. N. Dmitruk S. Kh. Batygov L. V. Moiseeva O. B. Petrova M. N. Brekhovskikh V. A. Fedorov 《Inorganic Materials》2007,43(7):793-796
We have studied the effect of In3+, Pb2+, Gd3+, and Cl (heavier ions) substitutions for Al3+, Ba2+, La3+, and F? on the crystallization stability and UV/IR optical properties of HBLAN fluorohafnatc glasses (HfF4-BaF2-LaF3-AlF3-NaF system). We obtained stable glasses containing InF3 and BaCl2 instead of AlF3 and BaF2, respectively, and offering increased IR transmission. The presence of CCl4 in the process atmosphere and the removal of oxygen-containing impurities via directional solidification are shown to have an advantageous effect on the optical quality of the glasses. The fluoride-chloride glasses are capable of accommodating about 1.5 times higher levels of rare-earth activators in comparison with their fluoride analogs. 相似文献
972.
Yun‐Hwei Shen 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(5):581-586
A novel strategy of sweep coagulation to treat low turbidity water is presented herein. Study findings demonstrated that an Na+‐saturated bentonite with medium cation exchange capacity (CEC) resulted in significant turbidity removal at a bentonite dosage of 30 mg dm?3. Bentonite dispersion with fully delaminated platelets tended to undergo a more porous type of coagulation with intense face‐to‐face interactions of platelets and effectively entrapped TiO2 particles in band‐type structures. This type of coagulation usually results in a large volume of settled flocs with a fluffy structure and excellent turbidity removal efficiency for sweep coagulation. The sign and magnitude of electrical charge on TiO2 particles has a minor effect on the efficiency of sweep coagulation. Copyright © 2005 Society of Chemical Industry 相似文献
973.
Hung‐Yee Shu 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2005,80(3):273-280
Liquid–liquid two‐phase epoxidation from cyclohexene and cyclooctene in aqueous potassium peroxymonosulfate (commercially available as Oxone®) solution was studied as an application in pollution prevention. To avoid potential emissions of volatile organic compounds an aqueous solution was employed to replace the usual chlorinated solvents used in epoxide production. A droplet column reactor and stirred tank reactor were used to investigate two‐phase synthesis of epoxide. An aqueous Oxone® solution was used to oxidize a dispersion of alkene droplets and form epoxide. The study of aqueous epoxidation in both reactors showed that the epoxidation of alkenes can be represented as a first order reaction with respect to alkene. The salting out effect of Oxone® concentration was studied in both reactors and found to be very similar at optimal conditions. In comparing the two reactors, it was found that the droplet column reactor produces larger quantities of product per unit reactor volume for the same reaction time. The objective of this study is to provide an alternative reactor design and synthesis route that can meet pollution prevention goals. Copyright © 2004 Society of Chemical Industry 相似文献
974.
Formaldehyde is used in ruminant feeding for different purposes including the protection of dietary proteins from ruminal degradation. The formaldehyde content of milk of goats fed various levels of formaldehyde-treated soybean oil-meal has been determined by using a sensitive HPLC method. Results showed a significant linear correlation between ingested formaldehyde and formaldehyde concentration in milk. About 0.02% of ingested formaldehyde was excreted in milk, as free formaldehyde. 相似文献
975.
E. L. Zil'berbrand A. A. Kozhushko V. I. Polozenko G. S. Pugachev A. B. Sinani 《Strength of Materials》1991,23(9):1007-1010
The process of interaction of a ductile projectile with a many times harder brittle target is analyzed in the 500–1000 m/sec range of velocities. The effect of hardness of the target and its fragmentation on the penetration depth is shown.Translated from Problemy Prochnosti, No. 9, pp. 60–62, September, 1991. 相似文献
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Seven ferrocene-bound polyester resins were prepared from fumaric acid and diethylene glycol in the presence of different ferrocene derivatives. To accomplish the incorporation of the organometallic moiety into the polyester resin chain, the cyclopentadienyl rings of ferrocene were substituted in the 1,1′ positions with reactive functional groups. The ferrocene derivatives used were: 1,1′-bis(1-hydroxyethyl) ferrocene 1 , 1,1′-ferrocene dicarboxylic acid 2 , and 1,1′-ferrocene diacetic acid 3 . The incorporation of an organometallic complex significantly increased the rate of the polyesterification process. In order of increasing rate enhancement, the effect was 2 < 3 < 1 . The effectiveness of ferrocene derivatives chemically incorporated into the polyester backbone during copolymerization with styrene was studied by monitoring the gel time, cure rate, and the resin properties. The efficiency of the copolymerization reaction of ferrocene-bound polymers with styrene decreased in the order 1 ≥ 3 > 2 . Mechanisms to account for these results are presented. Some of the strength related properties were also studied. 相似文献