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41.
Direct liquid fuel cells (DLFCs) are one of the most promising types of fuel cells due to their high energy density, simple structure, small fuel cartridge, instant recharging, and ease of storage and transport. Alcohols such as methanol and ethanol were the most common types of fuel used, although glycols and acids are also used. The main problem that arose in direct liquid fuel cells (DLFCs) was the high cost of the catalyst and the high catalyst loading. Other issues, such as fuel crossover, cathode flooding, the generation of various side products, fuel safety and unproven long-term durability, must also be solved to improve the performance of DLFCs. More research studies were required to increase its performance and foster commercialization. Currently, there were some commercial products using direct methanol fuel cells (DMFCs) and direct ethanol fuel cells (DEFCs), but the other types of DLFCs were generally still in the research stage. This paper aims to review the different types of liquid fuels directly used in fuel cells and identify their properties, challenges and applications. 相似文献
42.
43.
Lipase-catalysed ethanolysis of squalene-free shark liver oil was investigated. The mentioned shark liver oil was comprised mainly of diacylglycerol ether and triacylglycerols. In order to test discrimination against diacylglycerol ether, up to 10 different lipases were compared. The ratio of oil to ethanol and lipase stability were also evaluated. Surprisingly, lipase from Pseudomonas stutzeri was the fastest biocatalyst among all assayed, although poor discrimination against diacylglycerol ether was observed. The best results in terms of selectivity and stability were obtained with immobilised lipase from Candida antarctica (Novozym 435). Ethanolysis reaction after 24 h in the presence of Novozym 435 produced total disappearance of triacylglycerol and a final reaction mixture comprised mainly of diacylglycerol ethers (10.6%), monoacylglycerol ethers (32.9%) and fatty acid ethyl esters (46.0%). In addition, when an excess of ethanol was used, diacylglycerol ethers completely disappeared after 15 h, giving a final product mainly composed of monoacylglycerol ethers (36.6%) and fatty acid ethyl esters (46.4%). 相似文献
44.
DME synthesis from syngas via methanol has been carried out in a single-stage liquid phase reactor. Cu/ ZnO/Al2O3 and γ-Al2O3 were used together as methanol synthesis catalyst and dehydration catalyst, respectively. The influence of water on the catalytic
system was investigated mainly. Water affected the activity of methanol dehydration catalyst as well as methanol synthesis
catalyst. Thus, removal of water from the reaction system, by adding a dehydrating agent or controlling methanol formation
rate by the reaction parameters, was efficient in maintaining the high catalytic activity and stability.
Presented at the Int’l Symp. on Chem. Eng. (Cheju, Feb. 8-10, 2001), dedicated to Prof. H. S. Chun on the occasion of his
retirement from Korea University. 相似文献
45.
传统柴油机喷射器因二甲醚(DME)黏度太低会造成快速磨损,因而不能用于纯二甲醚内燃机中.介绍一种新型专用防磨损喷射器,利用旁通孔引流使二甲醚燃料不流过锥头杆阀的导向柱面,以避免锥头杆阀偶件受DME冲刷而引起磨损.利用Fluent软件对新型喷射器进行流量仿真,计算出旁通孔与锥头杆阀偶件环状间隙中DME的流量分布.计算结果验证了新型喷射器抵抗磨损的能力并得到一个防磨损的关键指标. 相似文献
46.
47.
A series of bisphenols containing ether linkage were prepared from halo phenol/dihalo compound and dihydroxy compounds in
the presence of K2CO3. The bisphenols were transformed to cyanate esters by treatment with cyanogen bromide using triethyl amine catalyst. The
structure of all the five bisphenols and the cyanate esters were structurally confirmed by FT-IR, 1H-NMR and 13C-NMR spectral methods and elemental analysis. The cyanate esters were cured at 100 °C (30 min) → 150 °C (30 min) → 200 °C
(60 min) → 250 °C (3 hr). The thermal properties of the cured resins were studied by DSC and TGA. DSC analysis shows that
these cyanate esters exhibit T
g in the range of 203–234 °C. The CE(c) has the highest glass transition temperature. The cyanate ester CE(e) shows the lowest
T
g which is due to its asymmetric structure. The initial degradation temperature of the cured resins was found to be in the
range of 324–336 °C. The Limiting Oxygen Index (LOI) value, determined by Van Krevelen’s equation, is in the range of 35.5–38.7. 相似文献
48.
49.
A new resin system for super high solids coating 总被引:11,自引:0,他引:11
This paper concerns a super high solids coating composed of two polymers; a silicone polymer containing SiH groups, and an acrylic or polyether polymer containing C=C groups. The silicone polymer was prepared by the equilibrium reaction of SiH containing polysiloxane and other organosiloxanes in the presence of sulfuric acid. Acrylic polymers were obtained by free radical polymerization of a monomer having an alkenyl group and other vinyl monomers. Homogeneous clear paints were available by adjusting compatibility of polymers, and VOCs of the paints were very low due to the low viscosity of a silicone polymer and the absence of polar functional groups in the coating system. The crosslinking reaction of this coating occurred through the hydrosilylation reaction between SiH and C=C groups. The performances of cured films, such as etch resistance and durability, were excellent. 相似文献
50.