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1.
Yusof Enis Nadia Md. Ishak Nurul N. M. Latif Muhammad A. M. Tahir Mohamed I. M. Sakoff Jennette A. Page Alister J. Tiekink Edward R. T. Ravoof Thahira B. S. A. 《Research on Chemical Intermediates》2020,46(4):2351-2379
Research on Chemical Intermediates - A series of tridentate ONS Schiff bases were synthesised via condensation by reacting 2,3-dihydroxybenzaldehyde with S-2-methylbenzyldithiocarbazate (S2MBDTC)... 相似文献
2.
Shaul K. Bar-Lev Daoud Bshouty Peter Enis Gérard Letac I-Li Lu Donald Richards 《Journal of Theoretical Probability》1994,7(4):883-929
A natural exponential family (NEF)F in ? n ,n>1, is said to be diagonal if there existn functions,a 1,...,a n , on some intervals of ?, such that the covariance matrixV F (m) ofF has diagonal (a 1(m 1),...,a n (m n )), for allm=(m 1,...,m n ) in the mean domain ofF. The familyF is also said to be irreducible if it is not the product of two independent NEFs in ? k and ? n-k , for somek=1,...,n?1. This paper shows that there are only six types of irreducible diagonal NEFs in ? n , that we call normal, Poisson, multinomial, negative multinomial, gamma, and hybrid. These types, with the exception of the latter two, correspond to distributions well established in the literature. This study is motivated by the following question: IfF is an NEF in ? n , under what conditions is its projectionp(F) in ? k , underp(x 1,...,x n )∶=(x 1,...,x k ),k=1,...,n?1, still an NEF in ? k ? The answer turns out to be rather predictable. It is the case if, and only if, the principalk×k submatrix ofV F (m 1,...,m n ) does not depend on (m k+1,...,m n ). 相似文献
3.
采用共沉淀法成功地合成了不同Mg掺杂量的Ce1-xMgxO2(x=0.05、0.10、0.15、0.20)固溶体催化材料,并运用透射电子显微镜(TEM)、X射线衍射(XRD)、氮气吸附-脱附测试、拉曼光谱、X射线光电子能谱(XPS)、CO2程序升温脱附(CO2-TPD)等技术对这些材料进行了表征。结果发现,通过调控CeO2晶格中Mg的含量,可以调控所制备的Ce1-xMgxO2催化材料的粒径、比表面积、表面缺陷等。其中Ce0.90Mg0.10O2展现了最佳的表面性质,具有最小的平均粒径(约5.8 nm),最大的比表面积(约136 m2·g-1)以及最高的表面氧含量(31.98%)。将Ce1-xMgxO2催化材料涂覆在堇青石蜂窝陶瓷上制成整体催化剂,考察其对CO2和CH3OH直接合成碳酸二甲酯的催化性能。在140℃、2.4 MPa、反应2 h的条件下,Ce0.90Mg0.10O2整体催化剂上碳酸二甲酯的收率高达20.21%,催化效果明显优于CeO2和其余的Ce1-xMgxO2(x=0.05、0.15、0.20)催化材料。 相似文献
4.
以CoCeOx复合氧化物为载体,采用沉积沉淀法制备了负载型的金催化剂,并通过不同温度的预处理控制Au的化学状态. 使用粉末X射线衍射、高分辨透射电子显微镜、程序升温还原和X射线光电子能谱对催化剂进行了表征,考察了在室温条件下该系列催化剂的一氧化碳氧化性能. 结果表明, Au/CoCeOx催化剂的CO氧化性能与催化剂表面Au 的含量成正比, Au 可能是反应的主要活性物种. 添加水汽对反应有一定的促进作用,但由于Au 不能稳定存在,特别是当催化剂表面Au 的含量过高时,在水汽的作用下Au 迅速发生歧化反应,使得催化剂的性能下降. 相似文献
5.
以4-氯-7-硝基苯并-2-氧杂-1,3-二唑、乙二胺和溴乙酸乙酯等为原料,合成4-氨基-7-硝基苯并-2-氧杂-1,3-二唑类衍生物(NBD-OEt),通过IR、NMR和MS对其进行结构表征。研究NBD-OEt的吸收光谱和荧光光谱性质,探讨其在H2O/EtOH(60/40, V/V) pH 7.40的HEPES缓冲体系中对Hg2 的响应,以及NBD-OEt与Hg2 的结合模式。结果表明, 随Hg2 的不断加入可诱使NBD-OEt在476nm的吸收峰红移至514nm,并有两个等吸收点(347nm、482nm);其荧光发射峰由536nm红移至559nm,且在525nm出现等发射点;通过Job plot法测定NBD-OEt与Hg2 以1:1的计量比结合。 相似文献
6.
Kapdan E Altinsoy N Karahan G Taskin H 《Isotopes in environmental and health studies》2011,47(1):93-100
Human body is exposed to ionising radiations both internally and externally by mainly high-energy cosmic ray particles incident on the earth's atmosphere and radioactive nuclides that originated in the earth's crust. The main objective of this study is to assess the health hazards due to environmental radiation sources in the city of Adapazari, one of the most important industrial cities of the country, Northwestern Turkey. For this purpose, natural radiation sources, external terrestrial radiations, cosmic radiations, and inhalation exposures have been investigated. The annual average external terrestrial radiation doses were determined as 0.08 and 0.35 mSv at outdoor and indoor atmospheres, respectively. The annual average cosmic radiation doses were found to be 0.08 and 0.05 mSv for directly ionising photon components and neutron components, respectively. The annual average inhalation exposure doses due to radon and thoron were obtained as 1.42 and 0.19 mSv, respectively, in the region. The annual average effective dose due to natural radiation sources was determined as a total of 2.35 mSv with the predetermined ingestion radiation dose. The lifetime cancer risk due to the background ionising radiations has been determined as 0.9×10(-2) for the residents of the Adapazari city, with the average lifespan of 70 years. The results of the effective doses due to background radiation sources in the region and the worldwide averages were discussed. 相似文献
7.
The ultrasonic signals in long bones contain multiple guided modes which are mutual superposed.The velocities of guided waves in long bones are very sensitive to cortical thickness (CTh).In this paper,Hilbert-Huang transform(HHT) was proposed to analyze multi-mode guided waves,which can decompose superposed waves into many independent modes.Then the group velocity of each mode was obtained at corresponding frequency,which was compared with the results of short time Fourier transform(STFT).The CTh was also obtained by comparing with the theoretical calculation.The results showed that the experimental determined thickness was in agreement with the actual CTh,indicating that measuring the velocity of the guided mode can be used to estimate the CTh.The HHT is an effective method to identify multimode guided waves. 相似文献
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10.
基于时频分布的盲信号分离方法研究长骨中的多模式导波信号 总被引:2,自引:0,他引:2
由于超声导波对长骨皮质骨的材料特性及厚度变化非常敏感,因此用导波评价长骨状况的研究已成为近年来的一个研究热点。在接收到的导波中,往往多种模式混叠在一起,使得进一步求取每种导波模式的群速度等与骨质状况密切相关的参数时遇到困难。本文采用基于时频分布的盲信号分离(TFBSS)方法对长骨中混叠的多模式进行分离,然后对分离后的单一导波模式求取群速度。研究结果表明TFBSS方法能够准确的分离出混叠的多模式导波,且实验测量的群速度与其理论值吻合。利用导波的群速度就可以得到长骨皮质骨的厚度,这对诊断其骨质状况具有重要意义。 相似文献