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1.
The effects of lanthanides at various concentrations on CaCO3 crystal growth were studied by X-ray diffraction (XRD), infrared spectra (IR), X-ray photoelectric energy spectra (XPS) and inductively coupled plasma mtms spectrometry (ICP-MS). It was found that the calcite, a stable form of CaCO3 in thermodynamics, is the predominant species. The research indicates that lanthanide ions (Ln3 ) can partly substitute the Ca2 in the lattice of CaCO3 crystals, and change the crystal characterization and direct the ordinal growth of CaCO3 crystals.  相似文献   

2.
Basic principles are offered to support the suggestion that use of special care space must be made with a mind toward prevention of obsolescence. Certain conventional design features should be examined critically and decisions made as to their applicability to the needs of a particular program.  相似文献   

3.
Dy3 isanimportantactivator .Ithasbeenexten sivelyappliedinmanyluminescentmaterials .Inre centyears ,someresearchershavestudiedthespec trumcharacteristicsofluminescentmaterialsdopedDy3 [1~ 6 ] andhaveobtainedsomemeaningfulre sults .InordertodevelopnewfluorescentmaterialsanddiscussthephotoluminescentruleofDy3 inthecomplexborate ,thispaperstudiesthephotolumines centcharacteristicsofDy3 inBa3La(BO3) 3host ,anddiscussestheinfluenceofthecharge to radiusratio(z/r)ofrareearthionRE3 andthecon…  相似文献   

4.
Ca3La(BO3)3中Dy3+的光致发光   总被引:2,自引:0,他引:2  
研究了Ca3La(BO3)3基质中Dy^3 的发射光谱和激发光谱。结果表明,强的激发峰值为351nm、367nm和386nm;Dy^3 的488nm和578nm发射的最佳浓度均为xDy=0.03;Dy^3 发射的黄光和蓝光强度比(用Y/B表示)随Dy^3 浓度的增加而逐渐增大;Dy^3 的^4F9/2→^6H15/2、^6H13/2跃迁发射的浓度猝灭机理均为电偶极-电偶极相互作用;同时还探讨了Ce^3 对Dy^3 发光的敏化作用。  相似文献   

5.
Dy^3+在(LaO)3BO3和(GdO)3BO3中的光致发光   总被引:1,自引:1,他引:0  
研究了Dy^3+在(LaO)3BO3和(GdO)3BO3中的光致发光;探讨了基质晶体结构、稀土离子RE^3+的电荷半径比(Z/r)和Dy^3+含量对(Dy^3+)发光强度及发光颜色的影响;分析了(GdO)3BO3中Bi^3+对Dy^3+发光的敏化作用及Dy^3+4F9/2→^6H13/2超灵敏跃迁发射的自身浓度猝灭机理。  相似文献   

6.
InfluenceofGa3+onPhotoluminescenceofCe3+XuChunxiang(徐春祥),LouZhidong(娄志东)(InstituteofMaterialPhysics,TianjinInstituteofTechno...  相似文献   

7.
边朝峰 《天津冶金》2007,(Z1):19-21
论述了3 200 m3高炉工程的施工原则、施工管理、施工机械管理的具体内容.通过严格的管理,保证施工进度、工程质量和安全文明施工.  相似文献   

8.
论述了大型综合项目安全管理内容、要求和办法.运用统计分析的方法,找出安全隐患控制重点,进行检查、控制,消除安全隐患,防止安全事故发生,为施工创造良好的安全环境.  相似文献   

9.
宋春林 《天津冶金》2007,(Z1):30-32
经营管理是企业管理重要工作之一,经营管理水平的高低,直接影响企业和工程项目的经济效益.在3 200 m3高炉工程建设中围绕工程合同,搞好经营计划、预算的审查,避免工程项目款项超拨失控现象.  相似文献   

10.
Regulation of the sterol-synthesizing mevalonate pathway occurs in part through feedback-regulated endoplasmic reticulum degradation of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-R). In yeast, the Hmg2p isozyme of HMG-R is regulated in this manner. We have tested the involvement of ubiquitination in the regulated degradation of Hmg2p, by using both genetic and direct biochemical approaches. Hmg2p degradation required the UBC7 gene, and Hmg2p protein was directly ubiquitinated. Hmg2p ubiquitination was dependent on UBC7 and was specific for the degraded yeast Hmg2p isozyme. Furthermore, Hmg2p ubiquitination was regulated by the mevalonate pathway in a manner consistent with regulation of Hmg2p stability. Thus, regulated ubiquitination appeared to be the mechanism by which Hmg2p stability is controlled in yeast. Finally, our data indicated that the feedback signal controlling Hmg2p ubiquitination and degradation was derived from farnesyl diphosphate, and thus implied conservation of an HMG-R degradation signal between yeast and mammals.  相似文献   

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13.
3-Oxobutylsulfoxyl-CoA has been produced by oxidation of S-3-oxobutyl-CoA, the thioether analog of acetoacetyl-CoA. Avian hydroxymethylglutaryl-CoA (HMG-CoA) synthase is inactivated by oxobutylsulfoxyl-CoA in a time-dependent fashion. Protection against inactivation is afforded by the substrate, acetyl-CoA, suggesting that inactivation involves modification of the enzyme's active site. Pretreatment of HMG-CoA synthase with the inactivator blocks the enzyme's ability to form Michaelis and acetyl-S-enzyme intermediates, supporting the hypothesis that modification is active-site directed. Incubation of enzyme with oxobutylsulfoxyl-[32P]CoA followed by precipitation with trichloroacetic acid indicates that inactivation correlates with stoichiometric formation of a covalent adduct between enzyme and a portion of the inactivator that includes the CoA nucleotide. The observation of reagent partitioning suggests that HMG-CoA synthase catalyzes conversion of oxobutylsulfoxyl-CoA into a reactive species that modifies the protein. Treatment of inactivated enzyme with DTT or other mercaptans restores enzyme activity and reverses the covalent modification with release of CoASH. Oxobutylsulfoxyl-CoA inactivates beta-ketothiolase and HMG-CoA lyase in a process that is also reversed by DTT. These three enzymes all contain active site cysteines, suggesting that inactivation results from disulfide formation between a cysteine and the CoA moiety of the inhibitor. The data are consistent with the hypothesis that enzymatic cleavage of oxobutylsulfoxyl-CoA results in the transient formation of a sulfenic acid derivative of CoA which subsequently reacts to form a stable disulfide linkage to protein.  相似文献   

14.
采用流体静力称重法研究了K<,3>AlF<,6>-Na<,3>AlF<,6>-AlF<,3>铝电解质体系的密度.探讨了K<,3>AlF<,6>,AlF<,3>含量和温度与K<,3>AlF<,6>-Na<,3>AlF<,6>-AlF<,3>体系密度的关系.实验结果表明:K<,3>AlF<,6>-Na<,3>AlF<,6>-AlF<,3>体系密度与温度成较好的线性关系,温度升高,密度降低;随着AlF<,3>含量的降低,体系的密度对温度的变化更加敏感.相同过热度下,固定KR(钾冰晶石含量),随着AlF3含量的增加,体系的密度呈现出不同的变化规律,相同过热度条件下,对于较低的KR=0.1值,随着AlF<,3>含量的增加,体系的密度逐渐下降,对于较高的KR=0.5值,随着AlF<,3>含量的增加,体系密度先降低后增加,存在最低点.相同过热度下,固定AlF<,3>含量,随着KR增加,体系密度也呈现出不同的变化规律,当AlF<,3>为22%,随着KR增大,体系密度变化不大;当AlF<,3>为26%,30%,随着KR增大,体系密度先降低后增加.  相似文献   

15.
本文对Bi_3PbSr_3Ca_3Cu_4O_y超导体进行了超导电性、磁阻、输运特性等的测量。并利用结构分析等方法,对超导体的颗粒超导性进行了研究。试验观察到了负磁阻效应、回滞和热激活行为,以及颗粒间晶界对输运特性的影响。并对以上结果进行了较详细的分析。  相似文献   

16.
以碳酸盐为沉淀剂,采用共沉淀法合成Ni1/3Co1/3Mn1/3CO3前驱体,再按照一定的锂配比将其烧结合成层状Li(Ni1/3Co1/3Mn1/3)O2。通过SEM及电性能测试仪等方法,研究了碳酸盐前驱体的合成条件,考察了碳酸盐前驱体的振实密度与合成时pH值、溶液浓度以及反应时间的关系。经过实验分析,在pH=8、溶液浓度C=2mol.L^-1、反应时间t=12-13h时,合成的碳酸盐前驱体Ni1/3Co1/3Mn1/3CO3振实密度达到最高值0.98g.cm^-3。  相似文献   

17.
论述了3 200 m3高炉工程从施工组织设计编制、方案确定、图纸审核至交(竣)工资料整理等各环节的施工技术管理办法及实施情况.总结了成绩,提出了应注意的问题.  相似文献   

18.
张俊卿  李玉生  周洋 《稀土》2007,28(4):87-89
利用DTA研究了EuCl3-NdCl3二元系相图,该体系有一个同分熔化化合物2EuCl3·3NdCl3,该化合物在635℃熔化,其成分为NdCl3,含量为60.0%(摩尔分数,下同),体系的2个低共熔点分别为462℃(NdCl3含量为33.2%)和582℃(NdCl3含量为71.4%).  相似文献   

19.
Graphiteintercalationcompounds(GlC)areaclassofnewtypefunctionalmaterials,whichwillpossiblybewidelyusedinthefuture.Manyscientistspayattentiont0thembecauseoftheirexcellentphysicalandchemica1properties,suchashighelectricalconductivity,highmagneticconductivityandhighcatalyticactivity["'j.Var-iousworkhasbeendoneinmanyc0untriesformanyyearsandgreatprogressinstructureandpropertydevelopmenthasbeen..hi...d[3~7].However,onlyafewinvestigationshavebeenmadeonrareearthchloridesgraphiteintercala-.tionc0mpoun…  相似文献   

20.
赵友  田绍文 《天津冶金》2007,(Z1):162-163
介绍了高炉炼铁工艺的几大组成系统中采用的先进控制技术,各个系统通过西门子DCS控制装置紧密结合,满足了高效率,低能耗的生产要求,达到了预期效果.  相似文献   

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