查询词典 furan

Theoretical studies on the halogen-bond in complexes of furan and dihalogen molecules have been carried out at the level of DFT and MP2.

用DFT和MP2方法研究了呋喃-XY (XY＝ClF， BrF， BrCl)体系分子间的相互作用，讨论了两种卤键类型 Y—X…O和Y—X…π的作用。

Other methyl nucleophiles includingMeMgBr, MeCeCl2, MeTiCl3, Me3Al, Me3ZnMgCl, MeMnClwere tried, but in all these cases no detectable amount of exo-C8-methylated product was obtained. Although protecting C3-carbonyl as 1,3-dioxolanes could be achieved, the serious enolization of C8-carbonyl was still problematic. Converting C9-furan ring to α,β-butenolide did depress the enolization, but desired C8-methylation was completely replaced by migration of the double bond of the butenolide.

在本论文的早期阶段，主要着眼于解决二环[3.2.1]-C8-羰基加成甲基所遇到的C9-呋喃环差向异构化和C3与C8两个羰基之间化学选择性的问题：通过引入不同金属降低甲基试剂的碱性并没有取得甲基化的成功；通过不同的方法将C3-羰基掩蔽，但是C8-羰基的烯醇化依然无法抑制；虽然通过将呋喃环转化为α，β-不饱和-γ-丁内酯可以抑制烯醇化，但内酯环上的双键迁移又成了新的竞争反应。

A novel furan resin was synthesized by polycondensation between furfuralcohol and furfural.

用糠醇和糠醛缩聚制备了新型呋喃树脂。

Good thermal stability and self-extinguishing behavior was observed with the cured polybenzoxazine resins. Second, furan-containing benzoxazine monomers, P-FBz, BPA-FBz, and 4FP-FBz were prepared using furfurylamine as a raw material. Formation of furfurylamine Mannich bridge networks in the polymerizations of P-FBz and BPA-FBz increased the cross-linking densities and thermal stability of the resulting polybenzoxazines. P-FBz and BPA-FBz- based polymers also exhibited high glass transition temperatures above 300℃, high char yields, and low flammability with a limited oxygen index value of 31. The dielectric (Dk3.21–3.39) and mechanical properties (high storage modulus of 3.0–3.9 GPa and low coefficient of thermal expansion of 37.7– 45.4 ppm) of the P-FBz and BPA-FBz-based polymers were superior or comparable to other polybenzoxazines. 4FP-FBz used for polybenzo- xazine modification by means of formation of benzoxazine hybridation with P-FBz.

第二部份以2-呋喃甲胺为起始物，制备了P-FBz、4FP-FBz与BPA-FBz 三个含呋喃官能基之氧代氮代苯并环己烷的单体；BPA-FBz与P-FBz於开环聚合中形成之Mannich bridge网状结构有效地提升聚氧代氮代苯并环己烷聚合物之交联密度与热安定性；Poly与Poly具有大於300℃之玻璃转移温度、高的焦炭生成率与具有31之极限氧指数(Limited oxygen index， LOI)的难燃性特质，Poly与Poly之介电常数(Dk=3.21~3.39)与机械性质[3.0~3.9 GPa的储存模数与37.7~45.4ppm之低热膨胀系数( Low coefficient of thermal expansion， Low CTE)]均较其他聚氧代氮代苯并环己烷为优；4FP-FBz具有低之介电常数(Dk=2.7)，以其作为降低介电常数之反应型改质剂，与P-FBz混成，证实可有效地降低Poly的介电常数。

Business company dispatch home was mixed first sets with suitable anhydride on July 8 hydric produce for raw material 1, 4- Ding Erchun (4 hydrogen of BDO)/ furan introduce device to finish function to assess, the mark is worn this technology realized success application in our country.

生意社7月8日讯国内首套以偏苯三酸酐和氢气为原料生产1，4-丁二醇/四氢呋喃的引进装置完成性能考核，标志着该技术在我国实现了成功应用。

The first court regarded, 2009 ,June 6 morning, the indictee zhuhua had conflict to tora shun's idea with reins.He passing by leiping city to buy two furan pesticide.

一审法院经审理查明，2009年6月6日上午，被告人祝华因与女友孙某感情上产生矛盾便产生教训孙某的念头，在经过乐平市镇桥时买了2包农药&呋喃丹&。

Seauckthorn juice can be appropriate drinks afer the diluting, which could block the N-nitroso Synthesis and also can block N-dimethylnitrosaminewhich can lead to cancer.The flavone of Seabuckthorn contains coumarin, isocoumarin, furan coumarins, lignin, as well as bitter polyphenols, 5 - serotonin, which are benefited for anti-cancer.

沙棘汁经稀释成宜引用的浓度后，能阻断N-亚硝酸的合成，另外沙棘汁对致癌物N二甲基亚硝胺也有阻断与防护的作用；沙棘黄酮中含有香豆素，异香豆素，呋喃香豆素，苦木素以及多酚类，5-色胺等具有综合抗癌作用的成分。

The reaction with propargyl sulfide gave a mixture of allenic sulfide and furan.The former is the [2,3]-sigmatropic rearrangement product,while the latter is derived from the furt...

同样条件下与炔丙基硫醚的反应则生成[2，3]-σ重排产物联烯和呋喃衍生物，后者是联烯进一步在Ru作用下重排的产物。

A range of oligoaryls having alternating para- or meta-benzene-furan rings is synthesized by rapid convergent/divergent method from the annlation of a propargylic dithioacetal and an aldehyde having a propargylic dithioacetal moiety as the substituent.

中文摘要结合分流法/汇集法，利用炔丙基硫缩酮单体和另一具有醛基的单体进行环化反应，可以迅速合成对位及间位取代苯环呋喃交错寡聚物。

Results: Nine compounds were obtained from the ethyl acetate fraction of C. speciosa and were identified as methyl chlorogenate, 5-O-cafeoyl quinic acid butyl ester, quinic acid butyl ester, 5-hydroxymethyl-furan-2-carbaldehyde, triacontanoic acid,-epicatichin, 7,8-dihydroxy-coumanrin, protocatechuic acid ethyl ester, and protocatechuic acid.

结果：从皱皮木瓜的乙酸乙酯萃取部位分离鉴定了9种化合物，分别为绿原酸甲酯，5-O-咖啡酰基－奎宁酸丁酯，奎宁酸丁酯，5-羟甲基－2-糠醛，三十烷酸，-表儿茶素，7，8-二羟基香豆素，3，4-二羟基苯甲酸乙酯，原儿茶酸。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。