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921.
猝冷骨架Ni催化剂的表征及不饱和有机官能团加氢行为研究 总被引:1,自引:1,他引:1
研究了采用猝冷法制备的Ni50Al50合金经碱溶液抽提铝后形成和多孔滑架Ni催化剂和催化行为,并与工业上广泛应用的Raney Ni催化剂进行了对比,用电感耦合等离子光谱(ICP)、X-射线衍射(XRD)、扫描电子显微镜(SEM)、比表面测定(BET)、X-射线光电子能谱(XPS)及氢吸附对催化剂进行了表征,活笥测试结果表明,猝冷合金催化剂(RQ Ni)对包括碳碳双键、硝基、羰基和腈青在内的不饱和有机官能团有较Raney Ni为高的加氢活性,这可以部分归结RQ Ni催化剂更大的活性比表积及两者由于制备方法不同而导致的结构差异。 相似文献
922.
观赏凤梨组织培养不同外植体的比较试验 总被引:5,自引:0,他引:5
选用观赏凤梨不同品种的老叶鞘、嫩叶鞘、顶芽、侧芽、茎段、叶片等不同组织作外植体 ,接种在诱导培养基为改良 MS+ 2 .0 mg· L- 1的 BA+ 5 .0 mg· L- 1的 2 ,4- D+ 0 .2 mg· L- 1的 IBA,及分化培养基为改良 MS+ 4 .0 mg· L- 1的 BA+ 0 .2 mg·L- 1的 IBA,培养 60 d进行统计 ,老叶鞘的愈伤组织三个品种平均诱导率为 74.6% ,丛生芽的诱导率平均数达 1 7.1 % ,次之是侧芽、顶芽 ,嫩叶鞘、茎段、叶片 ,后者能诱导出愈伤组织 ,不能诱导出丛生芽 相似文献
923.
运用逐步回归法筛选BP人工神经网络的输入元素改进BP网络的结构,并用于疏水分配常数及氢键作用能预测反相液相色谱保留值,结果表明,逐步回归法与人工神经网络相结合,能优化网络,大大提高网络收敛速度在很大程度上克服了通常BP网络过所合的缺点,较通常BP神经网络及回归法在处理构效关系方面有更强的信息处理能力和预测能力。 相似文献
924.
The Louzidian normal fault occurs as the eastern detachment fault of the Kalaqin metamorphic core complex. Field observations
and microstructural analyses reveal that the Louzidian-Dachengzi ductile shear zone developed in its lower-plate was genetically
related to sinistral strike-slips and extensional faulting. Two samples from this ductile shear zone yield 40Ar-39Ar plateau ages of 133 Ma (Bi) and 126 Ma (Kp), which are concordant with their isochron ages. The plateau age of 133 Ma (Bi)
records the formation age of the ductile shear zone. The inconsistent relationship between the earlier strike-slip ductile
shear zone and the later normal fault makes the Kalaqin Quasi-metamorphic core complex distinctive from Cordilleran metamorphic
core complex. These ages provide important geochronological data for putting constraints on the formation age and genesis
of such ductile shear zones. 相似文献
925.
Correlation of coral fluorescence with nearshore rainfall and runoff in Hainan Island, South China Sea 总被引:4,自引:0,他引:4
Under UV-laser excitation, the Porites coral from Longwan bay waters. Hainan Island, could emit yellow-green fluorescence. After fitting the data of the fluorescent intensity (FI) of the coral with the rainfall (RF) in nearshore area of Qionghai. a good relationship between FI and RF was found with a linear formula of RF = 889 — 4.54 FI and a correlation coefficient of 0.78. Based on this formula, the rainfall sequence from 1982 to 1997 has been reconstructed. The peak annual rainfall is usually related to global El nino events. By fitting the data of the fluorescent intensity and the runoff (RO). a quadric formula was obtained as RO = — 0.0279FI —18.59 FI - 950.9 with a correlation coefficient of 0.74. The reconstructed runoff sequence from 1982 to 1997 coincided with the rainfall occurrence. The results indicate that flood and drought incidents in coastal areas of the south China are affected by global change to a great extent. 相似文献
926.
Generally, the non-equilibrium plasma is produced at low pressure by a glow discharge (1.33 Pa—1.33 kPa) including the radio frequency (13.56 MHz), microwave (2450 MHz), AC or DC high voltage discharges. As a method to directly apply energy to a reaction system, some successful applications have been obtained in the fields such as chemical synthesis and decomposition at plasma, sputtering and filming, deposition at the gas state, polymerization, modification on the material surface, etching, ashing at low temperature and so on. For example, in 1999, Zhang et al.[1] got a high conversion rate of 98.2% for CH4 synthesis by a glow discharge at the condition of 850℃ with the catalyst of Ni/a-Al2O3. In 1990, Matsumoto et al.[2] reduced the concentration of CO2 from 10% to 8% by DC corona torch discharge with Ar catalyst at 0.08 kPa. In 1988, Boenig et al.[3] synthesized rare N2H4 and H2O2 with a glow discharge, in which N2H4 is a kind of pureness fuel and propellant of rocket. Tanaka et al.[4] investigated the synthesis of ammonia from nitrogen-hydrogen plasmas in radiofrequency and microwave discharges with catalysts of iron and molybdenum wires of 100 pieces at 620 K and 650 Pa. After 2-h synthesis, the amounts of synthesized NH3 and N2H4 were only 1.5 mmol/g and 2.5 mol/g, respectively. Because it is only at low pressure that electrons can obtain enough energy to carry out chemical reaction, the vacuum system is necessary, which results in the complicated technology and low production efficiency....... 相似文献
927.
Nanomanipulation plays an important role in nanofabrication, it is also a technology necessary in exploring the secrets of nanoworld, and it thus beco mesa start point to research future nanomachine. In this study, manipulation and cutting of carbon nanotubes have been conducted in order to examine whether we can move a nanocomponent from one site to another by using the tip of atomic fo rce microscope (AFM). The technique may also be valuable for providing the const ructive materials of nanofabrication. While exploring the method for manipulatin g and cutting of nanotubes, some new phenomena have been observed during the process. Results show that carbon nanotubes present a feature of deformation combin ing bending and distortion when subjected to large mechanical forces exerted by the tip of AFM. In special cases, long carbon nanotubes can be cut into two part s, by which we can remove the part where crystal lattice is flawed, and therefor e a perfect nanocomponent can be obtained. 相似文献
928.
IntroductionThecardinalityofafuzzysetisoneoftheproblemsthathavebeeninterestedinfuzzystatisticsduetoitsvarietyofapplication .Forexampleininsuranceactuary ,thefuzzysetofpeopleinthethirdstateisrelatedtothecardinality[1] .Alsothecardinalityiscloselyrelatedto… 相似文献
929.
普通高校体育教育专业学生专业思想教育探析 总被引:1,自引:0,他引:1
张辉 《杭州师范学院学报(自然科学版)》2002,(5)
运用综合研究方法 ,在对浙江省体育教育专业学生的入学动机、学习积极性、对体育教师职业认知等方面进行调查的基础上 ,分析造成学生专业思想淡薄、对体育教师职业感到悲观的主要原因 ,并就巩固学生的专业思想 ,加强对普通高校体育教育专业学生的专业思想教育提出了看法 . 相似文献
930.
在25℃下测定了十二烷基硫酸钠(SDS)/正戊醇/水三元体系的相平衡,确定了液晶区域的边界范围,在液晶区域内选取一系列样品点,用差示扫描量热法(DSC)与液晶纹理对照,研究了该体系的液晶结构特点.结果表明,在恒定温度下,该体系存在着两个液晶区域,并且随含水量的增加,液晶结构发生不同的变化.当组成固定时,体系的液晶相结构随温度升高也发生变化. 相似文献