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有氧条件下聚(氯乙烯)负载Pd(Ⅱ)配合物高效催化Heck和无铜Sonogashira反应(英文)

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催化学报 2014年第3期35卷 324-328页

作者： Mohammad Bakherad Ali Keivanloo shahrzad Samangooei School of Chemistry Shahrood University of Technology

A novel poly(vinyl chloride)-supported Pd complex was found to be a highly active catalyst for the Heck and Sonogashira reactions of aryl halides under aerobic *** complex is thermally stable,and can be easily recovered and *** catalyst was recycled for the Heck and Sonogashira reactions for five runs without appreciable loss of its catalytic activity,and with negligible metal leaching.

关键词： Heck 催化剂氯乙烯反应好氧条件 Pd 载体配合物

Comparison of bacterial community structures in two systems of a sewage treatment plant using PCR-DGGE analysis

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Journal of Environmental Sciences 2011年第12期23卷 2049-2054页

作者： abd El-Latif Hesham Rong Qi Min Yang State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Genetics Department Faculty of Agriculture Assiut University Assiut Egypt

The combination of PCR amplification of 16S rRNA genes with denaturing gradient gel electrophoresis （DGGE） analysis was used to reveal the compositions and dynamics of bacterial communities in a sewage treatment plant with two systems, i.e., an anoxic- anaerobic-aerobic system （inverted A2O） and an anaerobic-anoxic-aerobic one （conventional A2O） over a period from February to July 2009, during which both systems experienced serious sludge bulking problems. The DGGE patterns showed that there were many common bands in both systems, suggesting the high similarity of bacterial communities of the two systems. Meanwhile, the moving window correlation analysis showed that the two systems experienced different microbial community structure changes during the period, which might be related with the different situations of the occurrence and disappearance of sludge bulking, as being reflected by sludge volume index （SVI） values. Major bands of DGGE patterns of sludge samples were further sequenced. Phylogenetic affiliation indicated that the majority of the sequences obtained were affiliated with Actinobacteria, Firmicutes, Bacteroidetes/Chlorobi group and α- and β-Proteobacteria. Two sequences showed high similarities to typical filamentous bacteria Microthrix parvicella and Nostocoida limicola I, indicating that these bacterial species have been involved in the sludge bulking problems.

关键词： PCR-DGGE bacterial community activated sludge sludge bulking sewage treatment plant

Congenital sternal foramen in a stillborn Holstein calf

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Asian Pacific Journal of Tropical Biomedicine 2012年第1期2卷 83-84页

作者： shahrzad Azizi Mohsen Khosravi Bakhtiary Mehdi Goodarzi Department of Pathology School of Veterinary MedicineIslamic Azad University Graduated of Veterinary Medicine School Islamic Azad University Department of Clinical Sciences School of Veterinary MedicineIslamic Azad University

Congenital sternal foramen is an anomaly whose occurrence is rare in human but is especially unusual in *** defect was formed when fusion of multiple ossification centers was *** may be associated with other lesions in body organs especially cardiac *** the present study,we report a very rare case of congenital sternal foramen in a Holstein *** oval defect was like a gunshot wound and located at the lower third of the ***,the rest of skeleton system seems *** awareness of the anomaly is important for better diagnosis and treatment of diseases.

关键词： Sternal foramen Congenital anomalies Calf Congenital Sternum Human

Effect of Conductive Fillers on the Cyclic Stress-Strain and Nano-Scale Free Volume Properties of Silicone Rubber

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Chinese Journal of Polymer Science 2014年第5期32卷 558-567页

作者： M.H.abd-El Salam S.El-Gamal M.Mohsen D.M.abd El-Maqsoud Physics Department Faculty of Education Ain Shams University Physics Department Faculty of Science Ain Shams University

The effect of carbon black （CB） and graphite （G） powders on the macroscopic and nano-scale free volume properties of silicone rubber based on poly（di-methylsiloxane）（PDMS） was studied through thermal and cyclic mechanical measurements, as well as with positron annihilation lifetime spectroscopy （PALS）. The melting temperature of the composites （Tm） and the endothermic enthalpy of melting （ΔHm） were estimated by differential scanning calorimetry （DSC）. Tm and the degree of crystallinity （χc） of PDMS composites were found to decrease with increasing the CB content. This can be explained due to the increase in physical cross-linking which results in a decrease in the crystallite thickness. Besides, χc was found to be dependent on the filler type. Cyclic stress-strain behavior of PDMS loaded with different contents of filler has been studied. Mullins ratio （RM） was found to be dependent on the filler type and content. It was found that, RM increases with increasing the filler content due to the increase in physical cross-linking which results in a decrease in the size of free volume, as observed through a decrease of the o-Ps lifetime τ3 measured by PALS. Moreover, the hysteresis in PDMS-CB composites was more pronounced than in PDMS-G composites. Furthermore, a correlation was established between the free volume Vf and the mechanical properties of PDMS composites containing different fillers. A negative correlation was observed between Vf and RM.

关键词： Positron annihilation Positronium Free volume Si-rubber Composite Cyclic mechanical properties.

Measurements of natural radionuclides in soil samples from Upper Egypt

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Nuclear Science and Techniques 2008年第5期19卷 302-307页

作者： Shaban Ramadan Mohamed HARB Khaled SALAHEL DIN abd Elbaset ABBADY Mohamed abd Elleh ALI Rolf MICHEL Physics Department Faculty of ScienceSouth Valley University Center for Radiation Protection and Radioecology Hanover University (ZSR)

This paper presents the results of natural radioactivity measured for the soil of Qena using gamma-ray spectrometry at ZSR,Hanover University,*** samples of radioactive concentrations of ^(238)U-series (^(234)Th, ^(214)pb,and^(214)Bi),^(232)Th-series (^(228)Ac,^(212)pb,and ^(208)T1) and ^(40)K were *** objectives were set:(1) activity levels by surface soil sampling at 0～30 cm depth,(2) dose rates of gamma radiation,radium equivalent,index hazard, and effective dose,and (3) ambient dose rates.

关键词：土壤环境放射能 γ光谱测定法辐射暴露环境剂量

Optimized Numerical Model Based Assessment of Wave Power Potential of Marmara Sea

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Journal of Ocean University of China 2019年第2期18卷 293-304页

作者： abdOLLAHZADEHMORADI Yasin OZGER Mehmet ALTUNKAYNAK abdüsselam Hydraulics Division Department of Civil EngineeringIstanbul Technical University

Marmara Sea, located between Black Sea and Aegean Sea, is an important sea for ocean engineering activities. In this study, wave power potential of Marmara Sea was investigated using the third generation spectral wind-wave model MIKE 21 SW with unstructured mesh. Wind data was obtained from ECMWF ERA-Interim re-analyses wind dataset at 10 m with a spatial resolution of 0.1? for the period of 1994 to 2014. The numerical model was calibrated with measured wave data from a buoy station located in Marmara Sea. Mesh optimization was also performed to obtain the most suitable mesh structure for the study area. This study is the first that dealt with the determination of wave energy potential of Marmara Sea. The numerical model results are presented in terms of monthly, seasonal and annual average of wave power flux(k W m^(-1)). The maximum wave power flux is 1.13 kW m^(-1) and occurs in November. The overall annual mean wave power flux during 1994–2014 is found to be 0.27 kW m^(-1) in the offshore regions.

关键词： Marmara Sea MIKE 21 SW wave power potential ECMWF buoy wave data

Fair subcarrier-power allocation scheme for multiuser multicarrier systems

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Journal of Central South University 2015年第8期22卷 3033-3041页

作者： Mohammed abd-Elnaby Germien G.Sedhom Nagy W.Messiha Xu Zhu Fathi E.abd El-Samie Faculty of Electronic Engineering Menoufia University Deptartment of Electrical Engineering and Electronics University of Liverpool

The main objective of multiuser orthogonal frequency division multiple access(MU-OFDM) is to maximize the total system capacity in wireless communication systems. Thus, the problem in MU-OFDM system is the adaptive allocation of the resources(subcarriers, bits and power) to different users subject to several restrictions to maximize the total system capacity. In this work, a proposed subcarrier allocation algorithm was presented to assign the subcarriers with highest channel gain to the users. After the subcarrier allocation, subcarrier gain-based power allocation(SGPA) was employed for power and bit loading. The simulation results show that the proposed subcarrier-power allocation scheme can achieve high total system capacity and good fairness in allocating the resources to the users with slightly high computational complexity compared to the existing subcarrier allocation algorithms.

关键词： multiuser orthogonal frequency division multiple access (MU-OFDM) subcarrier-allocation power allocation fairness capacity

MHD Boundary Layer Flow of a Power-Law Nanofluid Containing Gyrotactic Microorganisms Over an Exponentially Stretching Surface

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Computers, Materials & Continua 2020年第2期62卷 525-549页

作者： Mohamed abd El-Aziz A.M.Aly Department of Mathematics Faculty of ScienceKing Khalid UniversityAbha61411Saudi Arabia Department of Mathematics Faculty of ScienceHelwan UniversityHelwan-Cairo11795Egypt Department of Mathematics Faculty of ScienceSouth Valley UniversityQena83523Egypt

This study focusses on the numerical investigations of boundary layer flow for magnetohydrodynamic(MHD)and a power-law nanofluid containing gyrotactic microorganisms on an exponentially stretching surface with zero nanoparticle mass flux and convective *** nonlinear system of the governing equations is transformed and solved by Runge-Kutta-Fehlberg *** impacts of the transverse magnetic field,bioconvection parameters,Lewis number,nanofluid parameters,Prandtl number and power-law index on the velocity,temperature,nanoparticle volume fraction,density of motile microorganism profiles is *** addition,the impacts of these parameters on local skin-friction coefficient,local Nusselt,local Sherwood numbers and local density number of the motile microorganisms are *** results reveal that the power law index is considered an important factor in this *** to neglecting the buoyancy force term,the bioconvection and nanofluid parameters have slight effects on the velocity *** resultant Lorentz force,from increasing the magnetic field parameter,try to decrease the velocity profiles and increase the rescaled density of motile microorganisms,temperature and nanoparticle volume fraction ***,an augmentation of power-law index drops the reduced local skin-friction and reduced Sherwood number,while it increases reduced Nusselt number and reduced local density number of motile microorganisms.

关键词： Bioconvection gyrotactic microorganisms magnetohydrodynamic nanofluid boundary layer power-law

Spatio-temporal variation of zooplankton community structure in tropical urban waterbodies along trophic and urban gradients

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Ecological Processes 2019年第1期8卷 539-550页

作者： Siti Balqis abd.Razak Zati Sharip Lake Research Unit Water Quality and Environment Research CentreNational Hydraulic Research Institute of MalaysiaMinistry of WaterLand and Natural ResourcesLot 5377Jalan Putra Permai43300 Seri KembanganSelangorMalaysia

The ecological impacts of urbanization and eutrophication on zooplankton communities in urban waterbodies have recently gained wide *** findings vary across species and urban *** the development of such changes affects the variation of biotic assemblages has only been explored to a limited extent in tropical urban *** and temporal variations of zooplankton community structure in 11 urban waterbodies in the Klang Valley,Malaysia were investigated along trophic and urbanization *** and water quality samples were collected three times,between May and November 2017,from two different locations in each *** three main zooplankton groups(rotifera,copepoda,and cladocera)were recorded from the study areas throughout the sampling *** zooplankton community structure,particularly with regard to rotifers and cladocerans,varied between lakes and *** diversity does not vary with lake size or distance from the city center but does vary with shoreline development index and urbanization *** zooplankton populations were dominated by rotifers,mainly Brachionus angularis at all study sites during the study period followed by copepods and *** total density of zooplankton was significantly highest(p<0.05)in the hypereutrophic lakes and during the dry *** diversity and rotifer species richness were negatively correlated with total phosphorus(TP).Diversity increased with urbanization and shoreline development,with rotifers as a potential bioindicator of trophic state in urban tropical lakes,due to their close relationship with TP.

关键词： Eutrophication Rotifer Tropical ponds Urban waterbodies Zooplankton diversity