首页 | 官方网站   微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 125 毫秒
1.
《中华手工》2005,(4):14-19
清乾隆年间(公元一七四四年),在洛阳老城密密麻麻的青砖青瓦民房中,出现了一组规模宏伟的建筑群,它占地一万五千多平方米,面对洛河,气势非凡。该建筑群挺过了改朝换代的天翻地覆,经历了解放战争的枪林弹雨,闯过了九死一生的“文革”焚火,挣扎着苟活到了今天,成了洛阳屈指可数的还有几许原汁原味的建筑群。正国为如此,它成了洛阳市内“全国重点保护单位”。如今,该古建筑群被作为洛阳民俗博物馆,向世人展示中原大地清代古建筑的特色,也展示河洛地区多姿多彩的民俗文化。  相似文献   

2.
鉴于新型锌合金的硅含量,可高于常见锌合金的10倍,在用光度法测硅前,对单硅酸的聚合性问题,进行了理论分析,并作了试验验证。结果表明,新型锌合金在测定条件下,单硅酸不聚合,所配制的一系列测硅检量液可隔夜使用,这既保证了测硅的准确度,又简化了操作,提高了分析速度,节约了药品。  相似文献   

3.
氨液浸出催化氧化制备硫酸铜晶体的方法探讨   总被引:1,自引:1,他引:1  
探讨了氨液浸出催化氧化制备硫酸铜的方法,并从热力学,动力学等角度进行了分析,对其反应可能性进行了论证,从多方面对反应机理进行了探讨。同时,将氨液浸出法与高温焙烧法作了对比,对其工业生产可能性作了分析,在多次实验的基础上,得出了较为合理的工艺条件。  相似文献   

4.
邢爱伟 《陶瓷》2011,(18):41-41
2008年,即便国际金融危机席卷全球,中国经济依然快速发展,高歌猛进。但在经济快速发展的背后,却萌生了一系列问题:喝杯牛奶中毒了,睡个午觉楼倒了,坐趟高铁追尾了,买个家具甲醛超标了……一系列的安全事故,加深了人们对生活环境的担忧。  相似文献   

5.
《粘接》2013,(4):15-15
曾听过这样一则故事,一位服装店老板收了两个徒弟。大徒弟聪明能干,师傅教的一点就通、一看就会,很快掌握了裁剪、缝纫等全套技术;小徒弟心灵手巧,但有点不安分,常常对服装设计提出一些奇思异想,弄得师傅哭笑不得。几年后两个徒弟都出师了,大徒弟自己开了个服装店,小徒弟则去了大城市打工,一直没有音讯。又过了若干年,大徒弟的手艺超过了师傅,成了小有名气的服装师傅,服装店生意也比较稳定。  相似文献   

6.
NONA的合成研究   总被引:1,自引:0,他引:1  
丁邦伟  吴书爱 《火炸药》1995,(3):17-18,29
完成了2,2',2″,4,4',4″,6,6',6″-九硝基三联苯的合成,并改进了其分离方法,使其纯度高于文献所报道,安定性更好。同时对合成的工艺条件进行了探索,部分地完成了实验室合成的工艺条件。  相似文献   

7.
狗年说狗     
春华 《火柴工业》2006,(1):29-31
我翻阅火花册,动物火花五彩纷呈,鸟类为题材的火花犹多,鸟常和花卉配在一起,真是鸟语花香。生肖中的各个动物,无一例外地进入了火花,且为数不少。年复一年,如到了龙年,许多厂家推出龙的火花。这时总有不少文章畅谈与火花的情缘,祝福龙年吉祥:龙凤呈样、龙腾虎跃、龙的传人……到了马年,说的是人欢马叫、万马奔腾。前年羊年,《羊年说羊》说了那么多美丽的神话和动人的传说。每年生肖火花总折射了国家昌盛,民族团结,人民幸福的升平景象,令火花收藏人增长了不少学问,增添了无限乐趣。  相似文献   

8.
尹大志  刘秀枝 《当代化工》2003,32(2):127-129
介绍了机械密封技术的基本原理,概述了机械密封技术的特色和优点,同时指出了其存在的一些不足。该技术在生产装置上应用后,避免了有毒、有害、高温易燃等介质外漏,减少或消除了安全隐患,降低了故障率,证明该技术成熟可行,能带来可观的经济效益,值得推广。  相似文献   

9.
针对纯碱包装过程中,碱尘颗粒小,易飞扬,易吸潮,结疤等特点。布袋除尘器运行周期短,故障率高,包装环境恶劣的实际情况,本文提出了一些改造办法,稳定了除尘器的运行,改善了工作环境。  相似文献   

10.
为了满足日益严格的安全环保要求,寻求更加经济高效的脱硫工艺,在塔河油田四号联合站设计时,进一步优化了稠油脱硫工艺。结合油田特性,反复论证,创新应用了“双塔合一”负压气提稳定脱硫工艺,经过近一年生产运行,效果显著,脱硫率>85%。该工艺进一步提高了H2S的脱除率,减少了气提气用量,同时降低了原油饱和蒸汽压,增加了轻烃产量,更能适应稠油处理、储运外销的需要,填补了国内稠油负压气提稳定脱硫技术应用的空缺。  相似文献   

11.
水泥水化热是中、低热水泥和核电工程用水泥的一项关键的技术指标。全球范围内测定水泥水化热的方法有溶解法、直接法/半绝热法、等温传导量热法三种。本文总结了中、美、欧相关方法标准,对其测试原理、仪器设备、试验过程等方面进行了比对,并对其在领域的应用做了简单的概括。  相似文献   

12.
Conclusions Studies of starting solutions of PPTA in sulfuric acid and of granules obtained under pressrue at low temperature, and of granules stored in a hermetic package, have been carried out by the methods of differential thermal analysis, turbidity spectrum and viscometry.On granulation of a solidified PPTA solution, short-term storage of the granules in a hermetic package, or short contanct of the granulated mass with air, no appreciable change in melting point or of the intrinsic viscosity of the system takes place.Long storage of a granulated solution, even in hermetic packages, can lead to a considerable decrease in the melting point of the crystal solvates, caused by an increase in defectiveness of crystal structure under the effect of moisture.Translated from Khimicheskie Volokna, No. 3, pp. 25–26, May–June, 1986.  相似文献   

13.
周辉  李灵  娄伦武 《化肥工业》2013,40(4):36-38
气化给煤装置自投运以来,出现了气化煤仓堵煤、称重给煤机输送皮带因跑偏而损伤以及清扫装置故障频繁等问题,多次造成气化系统减负荷运行。通过对出现的各种问题进行分析,找到了产生这些问题的原因,并有针对性地采用配煤和改进清扫链等措施,使出现的问题得到了极大的改善。  相似文献   

14.
A semi-empirical equation of state for metals is described. Its capabilities are demonstrated by the example of the equation of state for aluminum. New experimental data are presented on the location of the isentrope of aluminum for unloading from the state at p = 229.71 GPa on the shock adiabat to an aerogel (SiO2) of density 0.08 g/cm3. __________ Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 2, pp. 61–75, March–April, 2008.  相似文献   

15.
A thermochemical rather simple experimental technique is applied to determine the enthalpy of formation of Diperoxide of ciclohexanone. The study is complemented with suitable theoretical calculations at the semiempirical and ab initio levels. A particular satisfactory agreement between both ways is found for the ab initio calculation at the 6–311G basis This set level. Some possible extensions of the present procedure are pointed out.  相似文献   

16.
Based on the filtration equations with account of heat transfer in the heating region, the problem of instability of small perturbations of the wave front of filtration combustion of a gas is solved. Expressions for the growth decrement and critical transverse size of a perturbation are obtained. The problem of the wave-front stability is solved with account of the macroscopic redistribution of filtration in the system. The solution includes macroscopic characteristics such as the transverse size, the width of the high-temperature zone, etc. A method is proposed for taking into account the influence of the characteristics of the system on the evolution of perturbations. It is shown that small deformation perturbations of the front always increase to a certain amplitude; their subsequent development— continuation of their growth or stabilization—is determined by the characteristics of the system. Translated fromFizika Goreniya i Vzryva, Vol. 35, No. 5, pp. 3–5, September–October 1999.  相似文献   

17.
陈建文 《广东化工》2006,33(6):79-81
乙烯酮(双乙烯酮)是十分重要的化工中间体,其下游产品较多。江苏某化工厂开发生产乙烯酮(双乙烯酮)下游产品三十多个,年生产规模三万多吨,是国内以乙烯酮(双乙烯酮)为中间体生产精细化学品的综合骨干企业。针对乙烯酮(双乙烯酮)下游产品废水特点,该厂结合企业实际,开展了产品优化,结构调整,清洁生产,资源循环利用,节水降耗等工作,从源头削减了污染物的生产。同时投资二千多万元新建预处理装置三套,6000m3/d废水生化处理装置一套,使全厂乙烯酮(双乙烯酮)下游产品的废水得到了有效的治理。  相似文献   

18.
Process schemes for implementation of the optimum conditions of the final stage of orientational drawing of PP fibre are proposed based on the results of mathematical modeling. The existence of successive stages of transformation of the structure of PP fibre in the second stage of orientational drawing was experimentally confirmed with indirect indexes. The necessity of selecting the draw ratio that ensures completeness of the given stage of structural transformation is demonstrated. Structural schemes are proposed for automated control systems for selecting the optimum draw ratio in the first and final stages of orientational drawing and control of the structure of the spun polymer with indirect parameters.  相似文献   

19.
The objective of the study was to explore the effect of the degree of deacetylation (DD) of the chitosan used on the degradation rate and rate constant during ultrasonic degradation. Chitin was extracted from red shrimp process waste. Four different DD chitosans were prepared from chitin by alkali deacetylation. Those chitosans were degraded by ultrasonic radiation to different molecular weights. Changes of the molecular weight were determined by light scattering, and data of molecular weight changes were used to calculate the degradation rate and rate constant. The results were as follows: The molecular weight of chitosans decreased with an increasing ultrasonication time. The curves of the molecular weight versus the ultrasonication time were broken at 1‐h treatment. The degradation rate and rate constant of sonolysis decreased with an increasing ultrasonication time. This may be because the chances of being attacked by the cavitation energy increased with an increasing molecular weight species and may be because smaller molecular weight species have shorter relaxation times and, thus, can alleviate the sonication stress easier. However, the degradation rate and rate constant of sonolysis increased with an increasing DD of the chitosan used. This may be because the flexibilitier molecules of higher DD chitosans are more susceptible to the shear force of elongation flow generated by the cavitation field or due to the bond energy difference of acetamido and β‐1,4‐glucoside linkage or hydrogen bonds. Breakage of the β‐1,4‐glucoside linkage will result in lower molecular weight and an increasing reaction rate and rate constant. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 3526–3531, 2003  相似文献   

20.
The miscibility of various amorphous polybutadienes with mixed microstructures of 1,4 addition units (cis, 1,4 and trans 1,4) and 1,2 addition units have been investigated. The studies here involved optical transparency, differential scanning calorimetry, and small angle light scattering. It was found that a 90 percent (cis) 1, 4 addition polybutadiene was immiscible with high (91 percent) 1,2 addition polybutadiene. Reduction of the 1,2 content to 71 percent induced an upper critical solution temperature (UCST) with the cis 1,4 polymer. Polybutadienes with 50 percent and 10 percent 1,2 contents were miscible above the crystalline melting temperature of the cis 1,4 polybutadiene. Immiscibility of the 91 percent 1,2 addition polymer was also found with a 10 percent 1,2 polybutadiene. The latter polymer also exhibits an UCST with the 71 percent 1,2 polymer. The results are used to interpret the characteristics of blends of polybutadienes of varying microstructure.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司    京ICP备09084417号-23

京公网安备 11010802026262号