查询词典 condensation

Numerical simulation of dropwise condensation heat transfer of steam on copper, stainless steel, zinc, carbon steel surfaces were performed using the model of dropwise condensation heat transfer.

同时编制了珠状凝结换热的数值计算程序，并对不同压力下铜表面以水为介质的珠状凝结换热进行了数值模拟。

It was found that the dropwise and the film are coexisted in the condensation process, but only film condensation can be observed on the carbon steel surface.

进一步的凝结传热实验结果表明，高磷非晶镀层表面具有明显促进珠状凝结的效果，在凝结过程中表现为珠膜共存状态，而碳钢管表面仅出现膜状冷凝。

Their catalytic activities in the condensation reaction of cyclohexanone with ethanediol were studied.The results showed that the catalytic activity of SO_4~(2-)/ZrO_2-Ce_2O_3 in the condensation reaction ...

实验表明：(1)SO42-/ZrO2-Ce2O3在缩合反应中的催化活性比SO42-/ZrO2和SO42-/ZrO2要强；(2)引入适当数量的Ce2O3使得固体超强酸的酸强度增大；(3)当固体超强酸SO42-/ZrO2-Ce2O3的制备条件为焙烧温度550℃、焙烧时间4h、Ce2O3质量与ZrO2质量比2%时，酸对缩合反应的催化活性最高。

Ib was synthesized by condensation of phthalic anhydride with 2-methylresorcinol in fused AlCl〓/NaCl (5∶1), followed by selective acetylation, methylation, NBS bromination and condensation with sodium ethoxide.

邻苯二甲酸酐在熔融的三氯化铝-氯化钠(5：1)中和-2，6-二羟基甲苯环合得1，3-二羟基-2-甲基蒽醌〓后经选择性乙酰化、甲基化、NBS溴化、乙醇钠缩合得1-甲氧基-2-乙氧甲基-3-羟基蒽醌。

This paperindicated that it was good for condensation reaction when benzene-ring bearingelectron-attaching groups. It also showed that and the 6-hydroxyl group could bereacted with acyl halide, haloid ether and halo alkene, but not with halo alkane. It wasnot only the first time to find that the reaction product of D-mannitol and aromaticaldehyde is tri-condensation derivatives, but also the first time to obtain thep-phthaldehyde-sorbitol derivatives containing eight hydroxyl groups.

研究发现：苯环上有吸电子基团时对缩合反应有利；多元醇缩醛衍生物6-羟基除与酰氯反应外，也能和卤代酸酯、溴代烯反应，但不与卤代烷反应；首次发现D-甘露醇与醛反应主要得到三缩合物；首次合成了含有8个羟基的对苯二甲醛和山梨醇的缩合物。

In the second section, with ketone and hydroxylamine hydrochloride as the starting materials, 3-aminopropanol is prepared via three steps including reaction of ketone and hydroxylamine hydrochloride , condensation of ketoxime and acrylonitrile, and hydrogenation cracking of condensation product.

第二是3-氨基丙醇的制备，由酮肟丙烯睛缩合物催化氢化裂解制得：即先以酮、盐酸羟胺为起始原料在碱性条件下合成酮肟，再与丙烯腈反应生成酮肟丙烯腈缩合物后经催化氢化裂解制得3-氨基丙醇。

The first synthetic route uses 1,2,4-trimethoxybenzene and chloroacetonitrile in forming 2,4,5-trimethoxy-a-chlor-acetophenone under the anhydrous condition, then the intermediate condensates with papaverine forming the core pyrro[2,l-a]isoquinoline, followed by formation and lactonization to form the lactone ring. The second synthetic route uses prepared aldehyde with prepared ethyl nitroacetate by Knoevenagel condensation to obtain 2-Nitro-3-(2,4,5-tris-methoxy-phenyl)-acrylic acid ethyl ester and 2-Nitro-3-(2,4,5-tris-benzyloxy -phenyl)-acrylic acid ethyl ester etal intermediates. The lamellarin skeleton could arise from condensation of the papaverine and these intermediates by Michael reaction, the ester group is provided for subsequent lactonization. The third synthetic route uses coumarin or indan-l,3-dione derivatives and papaverine to form lamellarin under basic conditions.

第一条路线首先从1，2，4-三甲氧基苯出发与卤乙腈作用合成卤代芳酮中间体，然后与罂粟碱反应合成开链片螺素，最后经乙酰化、去保护、成内酯环得到片螺素；第二条路线由制备的芳醛和制备的硝基乙酸乙酯经缩合得到2-硝基-3-芳基丙烯酸乙酯，然后由该中间体与罂粟碱反应，在完成关环的同时也引入酯基，最后去保护、成内酯环得到片螺素；第三条路线是由香豆素或茚二酮出发，经溴代后的中间体与罂粟碱反应，得到片螺素的基本框架。

Firstly, the condensation heat transfer of steam-air mixture on the outside of a horizontal smooth tube and four square thread tubes is studied experimentally, and then, the condensation heat transfer on axisymmetrical surfaces as well as vertical plates of any kind of vapors containing noncondensable gases is analyzed theoretically.

本文作者先实验研究含空气的水蒸汽管外冷凝时水平光滑圆管和强化换热圆管的传热特性，实验时控制主流混合气体的压力和空气的质量成分，并探讨建立实验关联式的方法；然后对含不凝气体的蒸气在竖直平板和轴对称壁面上冷凝换热进行理论分析。

Aimed at the over proof problem of dissolved oxygen in condensation water for 300 MW units, a great deal of tests have been made, this paper deals with the effects of feed water pump sealing water, seal steam heater drain water, overcool degree of condensation water , and condenser makeup water, and puts forward some effective improving measures.

针对某电厂300MW机组凝结水溶氧超标的问题，进行了大量的试验研究，提出了给水泵密封水、轴加疏水、凝结水过冷度以及凝汽器补水等对凝结水溶氧量的影响，并对此提出了一些行之有效的改进措施。

Condensation water plays an important role in sustaining the vegetation and eco-environment in the desertification areas. The development of condensation water may be influenced by day and night trends of temperature and moisture in the vadose zone.

凝结水对维持荒漠地区的植被生态环境起到至关重要的作用，而凝结水的形成机制又反映在包气带地温与含水量的昼夜动态过程中。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。