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Comparison between hydrogen-transfer and fluoro-transfer reactions on the microcanonical unimolecular rate constants

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Chinese Journal of Chemistry 1995年第5期13卷 391-395页

作者： Feng, WL zh.ng, SW Wang, Y Wu, JN Li, zh BEIJIng NORMAL UNIV DEPT CHEMBEIJING 100875PEOPLES R CHINA

The microcanonical rate constants for the hydrogen-transfer process of HCCF (reaction 7) and the fluoro-transfer process of FCCF (reaction 8) are carried out with tunneling correction and curvature correction. The results show that the tunneling effects and curvature effects on the rate constant of reaction 7 is quite different from that of reaction 8. The rate constants for different rotational states are also studied for these reactions.

关键词： microcanonical rate constant tunneling effect curvature correction

Growth performance and scale insect infestation of Shorea leprosula in a common garden experimental plot

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Journal of Forestry Research 2023年第3期34卷 781-792页

作者： Chin Hong ng Kevin Kit Siong ng Soon Leong Lee Rempei Suwa Chai Ting Lee Lee Hong Tnah Forest Research Institute Malaysia 52109 KepongSelangorMalaysia Forestry Division Japan International Research Center for Agricultural SciencesTsukubaIbaraki 305‑8686Japan

Many tree planting programmes have long been initiated to increase forest cover to mitigate the effects of global climate *** planting requires careful planning at the project level,including using suitable species with favourable ***,there is a paucity of improvement data for tropical tree *** experimental common garden of Shorea leprosula was established to study traits related to growth performance which are key factors in planting *** of *** were collected from nine geographical forest *** study the effects of genetic variation,seedlings were planted in a common environment following a randomized complete block *** performance data collected 2017‒2019,one population showed the highest coefficient for relative height growth,significantly higher than most of the other ***,this population from Beserah also exhibited the lowest coefficient for scale insect *** study provides preliminary results on growth performance and susceptibility to scale insect infestation in *** and the first common garden experiment site conducted on dipterocarp *** lays a foundation for future genome-wide studies.

关键词： Root collar diameter Height Scale insect Relative growth rate Dipterocarp

Second-order optimality conditions f or minimizing a maxfunction

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Science China Mathematics 2000年第7期43卷 722-733页

作者：黄力人 K.F.ng Department of Mathematics South China Normal University Guangzhou 510631 China Department of Mathematics The Chinese University of Hong KongHong KongChina Correspondence should be addressed to K.F.Ng

We study Chaney's and Ben-Tal-Zowe's second-order directional derivatives with applications in minimization problem for max-functions of the formh(x): = max {f(x, τ); τ ∈T},where T is a compact metricspace. We impr... 详细信息

关键词： max-f unction sup-type function second-order optimality condition nonsmooth optimization.

Solving sparse non-negative tensor equations： algorithms and applications

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Frontiers of Mathematics in China 2015年第3期10卷 649-680页

作者： Xutao LI Michael K. ng School of Computer Engineering Nanyang Technological University Singapore 639798 Singapore Centre for Mathematical Imaging and Vision and Department of MathematicsHong Kong Baptist University Hong Kong China

We study iterative methods for solving a set of sparse non-negative tensor equations （multivariate polynomial systems） arising from data mining applications such as information retrieval by query search and community discovery in multi-dimensional networks. By making use of sparse and non-negative tensor structure, we develop Jacobi and Gauss-Seidel methods for solving tensor equations. The multiplication of tensors with vectors are required at each iteration of these iterative methods, the cost per iteration depends on the number of non-zeros in the sparse tensors. We show linear convergence of the Jacobi and Gauss-Seidel methods under suitable conditions, and therefore, the set of sparse non-negative tensor equations can be solved very efficiently. Experimental results on information retrieval by query search and community discovery in multi-dimensional networks are presented to illustrate the application of tensor equations and the effectiveness of the proposed methods.

关键词： Nonnegative tensor multi-dimensional network information retrieval community iterative method multivariate polynomial equation

Magnetic properties and microstructures of SnO_2 doped Mn-Zn ferrites

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Rare Metals 2006年第z1期25卷 445-449页

作者： ng Foong-Kee SALE Frank R. School of Technology Tunku Abdul Rahman College PO Box 10979 50932 Kuala Lumpur West Malaysia School of Materials The University of Manchester Grosvenor Street Manchester M17HS United Kingdom

The effects of additive SnO2 (0.4wt.%), with and without SiO2 (0.02wt.%) and/or CaO (0.04wt.%), on the microstructure and magnetic properties of Mn-Zn ferrites were reported. The results reveal that SnO2 on its own increases the initial permeability (μi) slightly, but SnO2 with SiO2 and/or CaO decreases the values of μi. However, ferrites with SnO2 additions have reduced power losses. The separate contributions of hysteresis loss and eddy current loss to the total power loss show that SnO2 (with or without SiO2 and/or CaO) doping increases the hysteresis loss slightly, but SnO2 doping alone reduces the eddy current loss significantly (～14%). The additions of SiO2 or CaO further decrease the eddy current loss, and by interaction of SnO2-CaO-SiO2, the eddy current loss is reduced by more than 20%. These magnetic and microstructural effects were discussed in terms of the additive-impurity interaction, the existence of grain boundary phases, and the effective bulk and grain boundary resistivities of the ferrites.

关键词： Mn-Zn ferrites SnO2 doping magnetic properties microstructure

ELECTROHYDRODYNAMIC DISPERSION OF DEFORMABLE AEROSOLS IN THE PRESENCE OF AN ELECTRIC FIELD AND CHEMICAL REACTION USIng TAYLOR DISPERSION MODEL

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Journal of Hydrodynamics 2011年第2期23卷 247-257页

作者： RUDRAIAH N. DEVARAJU N. ng Chiu-On UGC-CAS in Fluid Mechanics Department of Mathematics Bangalore University Bangalore-560 001 India National Research Institute for Applied Mathematics (NRIAM) Bangalore-560 070 India Department of Mechanical Engineering The University of Hong Kong

Under the effects of electric field and chemical reaction, the problem of dispersion of aerosols in a poorly conducting fluid in a channel is solved analytically using the mixture theory together with a regular perturbation technique. It is shown that the aerosols are dispersed relative to a plane moving with the mean speed of atmospheric fluid as well as the mean speed of agglomeration of aerosol with a relative diffusion coefficient, called the Taylor dispersion coefficient. This coefficient is numerically computed and the results reveal that it increases with an increase in the electric number, but decreases with increasing porous parameter. The physical explanations for the phenomena are given in this article.

关键词： dispersion aerosols electrohydrodynamics mixture theory

Evaluation of solubility of polycyclic aromatic hydrocarbons in ethyl lactate/water versus ethanol/water mixtures for contaminated soil remediation applications

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Journal of Environmental Sciences 2012年第6期24卷 1064-1075页

作者： Chiew Lin Yap Suyin Gan Hoon Kiat ng Department of Chemical and Environmental Engineering The University of Nottingham Malaysia CampusJalan Broga43500 SemenyihSelangor Darul EhsanMalaysia Department of Mechanical Materials and Manufacturing Engineering The University of Nottingham l~lalaysia Campus Jalan Broga 43500 Semenyih Selangor Darul Ehsan Malaysia

Solubility data of recalcitrant contaminants in cosolvents is essential to determine their potential applications in enhanced soil *** solubilities of phenanthrene,anthracene,fluoranthene and benzo[a]pyrene in ethyl lactate/water and ethanol/water mixtures were measured using equilibrium *** cosolvency powers derived from solubility data were then applied to the model developed from the solvophobic approach to predict the capability of ethyl lactate and ethanol in enhancing the desorption of contaminants from *** ethyl lactate and ethanol cosolvents were shown to be able to enhance the solubilisation of the tested four polycyclic aromatic hydrocarbons by 〉 4 orders of magnitude above the levels obtained with water ***,ethyl lactate demonstrated a greater capacity to enhance PAH solubility than *** cosolvency powers of ethyl lactate/water system obtained from the end-to-end slope （σ） and the end-to-half slope （σ 0.5） of the solubilisation curve were 1.0-1.5 and 2.0-2.9 higher than ethanol/water system *** line with this,ethyl lactate/water was demonstrated to enhance the desorption of contaminants from soil by 20%-37% and 18%-61% higher compared to ethanol/water system in low organic content and high organic content soils respectively,with a 2：1 （V/W） ratio of solution：soil and with cosolvent fraction as low as *** the exception of benzo[a]pyrene,the experimental desorption results agreed fairly with the predicted values,under an applied solution：soil ratio that was enough to hold the capacity of released contaminants.

关键词： polycyclic aromatic hydrocarbon solubility desorption ethyl lactate ethanol

Risk of ischaemic and haemorrhagic stroke in Chinese undergoing percutaneous coronary intervention treated with potent P2Y12 inhibitor versus clopidogrel

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Stroke & Vascular Neurology 2022年第4期7卷 310-318,I0015-I0019页

作者： Andrew Kei-Yan ng Pauline Yeung ng April Ip Kui Kai Lau Chung-Wah Siu Cardiac Medical Unit Grantham HospitalHong KongHong Kong Department of Adult Intensive Care Queen Mary HospitalHong KongHong Kong Department of Medicine The University of Hong KongHong KongHong Kong The State Key Laboratory of Brain and Cognitive Sciences The University of Hong KongHong KongHong Kong

Background Stroke after acute coronary syndrome(ACS)can be *** is uncertain whether the risks of ischaemic stroke or intracranial haemorrhage(ICH)are associated with different choices of P2Y12 inhibitors(potent P2Y12 inhibitors such as ticagrelor and prasugrel vs clopidogrel).Even though East Asians are known to have different thrombotic and haemorrhagic profiles from Caucasians,data on Chinese patients are *** This was a retrospective cohort study conducting in Chinese patients with ACS who underwent first-ever percutaneous coronary intervention from 14 hospitals in Hong Kong between 2010 and *** primary efficacy endpoint was ischaemic *** secondary efficacy endpoint was a composite outcome of thrombotic events including all-cause mortality,non-fatal myocardial infarction and ischaemic *** primary safety endpoint was *** secondary safety endpoint was a composite of major bleeding *** After adjustment of baseline characteristics by 1:1 propensity score matching,a total of 6220 patients(3110 on each group)were *** with clopidogrel,potent P2Y12 inhibitors were associated with a lower risk of ischaemic stroke(HR 0.57;95%CI 0.37 to 0.87;p=0.008)and a lower risk of thrombotic events(HR 0.77;95%CI 0.66 to 0.90;p=0.001).Potent P2Y12 inhibitor was associated with similar risk of ICH(HR 0.65;95%CI 0.34 to 1.25,p=0.20)and major bleeding(HR 0.83;95%CI 0.68 to 1.01,p=0.069).Conclusions Potent P2Y12 inhibitors were associated with a lower adjusted risk of ischaemic stroke and thrombotic events,compared with *** risks of ICH and major bleeding were similar.

关键词： P2Y12 coronary haemorrhagic

Experimental investigation of the effect of flow turbulence and sediment transport patterns on the adsorption of cadmium ions onto sediment particles

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Journal of Environmental Sciences 2007年第6期19卷 696-703页

作者： HUAng Sui-liang ng Chiu-on GUO Qi-zh.ng Numerical Simulation Group for Water Environment College of Environmental Science and Engineering Nankai University Tianjin 300071 China Deptartment of Mechanical Engineering The University of Hong Kong Pokfulam Road Hong Kong Department of Civil and Environmental Engineering Rutgers State University of New Jersey 623 Bowser Road Piscataway NJ 08854 USA

The mechanism of flow turbulence, sediment supply conditions, and sediment transport patterns that affect the adsorption of cadmium ions onto sediment particles in natural waters are experimentally simulated and studied both in batch reactors and in a turbulence simulation tank. By changing the agitation conditions, the sediment transport in batch reactors can be categorized into bottom sediment-dominated sediment and suspended sediment-dominated sediment. It is found that the adsorption rate of bottom sediment is much less than that of suspended sediment, but the sediment transport pattern does not affect the final （equilibrium） concentration of dissolved cadmium. This result indicates that the parameters of an adsorption isotherm are the same regardless of the sediment transport pattern. In the turbulence simulation tank, the turbulence is generated by harmonic grid-stirred motions, and the turbulence intensity is quantified in terms of eddy diffusivity, which is equal to 9.84F （F is the harmonic vibration frequency） and is comparable to natural surface water conditions. When the turbulence intensity of flow is low and sediment particles stay as bottom sediment, the adsorption rate is significantly low, and the adsorption quantity compared with that of suspended sediment is negligible in the 6 h duration of the experiment. This result greatly favors the simplification of the numerical modeling of heavy metal pollutant transformation in natural rivers. When the turbulence intensity is high but bottom sediment persists, the rate and extent of descent of the dissolved cadmium concentration in the tank noticeably increase, and the time that is required to reach adsorption equilibrium also increases considerably due to the continuous exchange that occurs between the suspended sediment and the bottom sediment. A comparison of the results of the experiments in the batch reactor and those in the turbulence simulation tank reveals that the adsorption ability of the sedimen

关键词： water flow sediment transport pollutant interactions turbulence, adsorption