查询词典 urea

Main connections are methenyl ether linkage and methenyl. From the end of heat preservation to the end of whole reaction, main reaction was polycondensation. In general, there were three types reaction among melamine modified UF resin, urea-formaldehyde system, melamine-formaldehyde system and melamine-urea-formaldehyde system.

保温反应结束直到整个反应结束，缩聚反应为主要反应类型，三聚氰胺改性脲醛树脂中存在着3种反应体系：尿素甲醛的反应体系、三聚氰胺甲醛反应体系和三聚氰铵尿素甲醛共缩合反应体系。

When using urea-hydroperoxide as oxygent, just the trimethylphosphine adsorbed on the Lewis acid sites in TS-1 zeolite was oxidized. It further confirmed that the hydroperoxo-titanium species formed by the interaction between the titanium in Lewis acid sites and urea-hydroperoxide are the active oxidation center, and the titanium in the framework as Lewis acid sites enhances the oxidation ability of hydroperoxide. 3. Phenylacetaldehyde and benzaldehyde are found to be the major products in the catalytic oxidation of styrene over TS-1 zeolite, and styrene epoxide is not as speculated detected.

当以过氧化氢尿素为氧化剂时，室温条件下吸附在TS-1分子筛Lewis酸性位的三甲基膦即能被氧化，由此进一步证明，TS-1分子筛中由Lewis酸性位的骨架钛与过氧化氢相互作用形成的过氧化钛物种是三甲基膦氧化反应的活性中心，骨架钛作为Lewis酸中心提高了过氧化氢的氧化能力。

A flame retarding and smoke suppressing agent polyphosphoric cyanamine urea was prepared with phosphoric acid,melamine and urea as the raw materials.

以磷酸、三聚氰胺、尿素为原料制备阻燃抑烟剂聚磷酰氰胺脲，然后将其应用于TDE-85#环氧树脂中，以顺丁烯二酸酐为固化剂制备了阻燃抑烟环氧树脂。

The reactions that isocyanate reacted to cellulose, semicellulose, lignin, and water in timber to form the urethane and urea are basic knowledge for the adhesion of isocyanate-terminated polyurethane resins to wood. It has significant meaning to understand that different quantity of urethane and urea affect the strength of adhesive bond.

异氰酸酯基与木材中的纤维素、木素、半纤维素和水在一定条件下生成氨基甲酸酯和取代脲的反应是聚氨酯胶粘剂与木材胶接的基础反应，研究氨基甲酸酯和取代脲的生成量对胶接强度的影响具有积极的理论意义和实践指导价值。

Maximum gallic acid yield ( 83.8%) was obtained after Escherichia coli was cultivated aerobicly in 100mL liquid culture medium with 7g/L tara tannin extract and 1g/L complementary urea on snaker (120 rpm) at initial pH 6.0 and 28℃for 28h, while maximum tannin reduction rate (43.6%) was obtained after 5g/L glucose was supplied instead of urea in the same degrading conditions above.

当塔拉单宁浸提物浓度为7 g/L、补充的尿素浓度为1 g/L、初始pH为6.0、250 mL锥形瓶装液量为100 mL、28℃振荡(120 rpm)培养28 h时，棓酸产率可达83.8%；当补充的葡萄糖浓度为5 g/L时，塔拉单宁降解率可达43.6%。

Adhesive has environmentally-friendly products are mainly urea-formaldehyde resin, melamine urea-formaldehyde resin and modified phenolic resin; concrete water reducer products are mainly water-reducing agent has Sulphamate, polycarboxylate water reducer and superplasticizer melamine.

胶粘剂产品主要有环保型脲醛树脂、三聚氰胺改性脲醛树脂和酚醛树脂；混凝土减水剂产品主要有氨基磺酸盐减水剂、聚羧酸减水剂和三聚氰胺减水剂。

The results showed that granular urea amended with dicyandiamide and N- thiophosphoric triamide induced the highest soil nitrate-reductase activity, granular urea brought about the highest soil urease activity and microbial biomass C a...

结果表明，施用硝化抑制剂和脲酶抑制剂涂层大颗粒尿素肥料的土壤硝酸还原酶活性最高；施用大颗粒尿素，脲酶活性最强，微生物量碳、氮最高。

Acrylic resin as coated material, N- thiophosphric triamide and dicyandiamde as biological inhibitors, with Fluid Bed spraying biological inhibitors on urea granular surface and coated it with acrylic resin afterward, four coated urea fertilizers were made for monitoring slow/controlled effects of coated fertilizers in distilled water.

采用丙烯酸树脂为包膜材料，以NBPT和DCD为生化抑制剂，利用流化床对尿素进行涂层生化抑制剂及包膜，制备4种包膜肥料，对这些包膜肥料在水中的控释效果进行了研究。

Acrylic resin as coated material, N- thiophosphric triamide and dmyandlamde as biological inhibitors, with Fluid Bed spraying biological inhibitors on urea granular surface and coated it with acrylic resin afterward, four coated urea fertilizers were made for monitoring slow/controlled effects of coated fertilizers in distilled water.

采用丙烯酸树脂为包膜材料，以NBPT和DCD为生化抑制剂，利用流化床对尿素进行涂层生化抑制剂及包膜，制备4种包膜肥料，对这些包膜肥料在水中的控释效果进行了研究。

In this dissertation, the efforts were focused on design and synthesis of chiral tmsymmetrical urea, cholic acid and heteroaromatic molecular tweezers and their molecular recognition as well as enantioselective recognition. A series of useful and creative results have been obtained.Three new types of chiral molecular tweezers containing unsymmetrically disubstituted urea unit, four new types of chiral molecular tweezers based on steroid cholic acid and one type of heteroaromatic molecular tweezers involving multiple hydrogen-bonding site have been designed and synthesized.

本文致力于新型手性不对称脲、胆甾和芳杂环类分子钳受体的设计合成及其对阴离子、中性分子和手性分子的识别及对映选择性识别性能研究，取得了一系列具有重要学术意义与应用前景的创新性结果。

I didn't watch TV last night, because it .

昨晚我没有看电视，因为电视机坏了。

Since this year, in a lot of villages of Beijing, TV of elevator liquid crystal was removed.

今年以来，在北京的很多小区里，电梯液晶电视被撤了下来。