检索结果-南通市图书馆

国际医学放射学杂志 2021年第3期44卷 365-366页

作者： J.S.Yun m.h.Lee S.m.Lee J.S.Lee h.J.Kim S.J.Lee 赵大伟

摘要目的评价常规mRI及扩散加权成像(DWI)鉴别良恶性外周神经鞘瘤(PNST)的价值。方法 2014年9月—2017年12月收集83例经病理证实的、躯干或四肢良恶性

关键词：

Radiation Shielding Analysis and Design of tof PET-CT Facility at Institute of Nuclear medical Physics under Bangladesh Atomic Energy Commission, Bangladesh

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of medical Physics, Clinical Engineering and Radiation Oncology 2019年第1期8卷 1-8页

作者： m. F. Uddin R. Khatun S. Akter h. m. Jamil A. N. monika m. A. Rahaman R. P. Das R. A. Sharmin m. m. Rahman m. m. Ahasan Institute of Nuclear medical Physics AERE Savar Dhaka Bangladesh Atomic Energy Centre Dhaka Bangladesh

high resolution (4 mm) tof PET-CT (positron emission tomography-computed tomography) from Philips of model Ingenuity TF is newly installed at Institute of Nuclear medical Physics (INmP). 128 slice CT component incorporated with PET provides comparatively lower dose than the 511 keV annihilation photons associated with positron decay from PET scan. So, for designing shielding in our PET-CT facility, only 511 keV annihilation photons energy has been considered. The main objective of this paper is to show what measures have been taken to protect patients, occupational workers as well as environment from PET-CT radiation hazard through a cost effective design that satisfy the national regulatory demand. In this paper, AAPm (American Associations of Physicists in medicine) Task group 108 analysis for PET and PET-CT shielding requirements is followed for our PET-CT facility shielding design. From theoretical calculation as shielding requirement, 1.1 cm Pb thickness or, 13 cm concrete thicknesses are found. Practically, all walls and ceiling are of 30.48 cm (1 foot) thick made of concrete with density 2.35 gcm-3 for more safety. As x-ray from CT is not taken into account for shielding analysis, Bangladesh Atomic Energy Commission (BAEC) conducted an extensive radiation survey at controlled, supervised and public area for CT. The report that is found meets the national regulatory requirements.

关键词： Radiation Protection PET-CT Shielding FDG

Influence of ph on Formation of Taranakites

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 1999年第1期9卷 35-44页

作者： ZhOUJIANmIN P.m.hUANG InstituteofSoilScience theChineseAcademyofSciencesP.O.BOx821Nanjing210008China DepartmentofSoilSci

monoammonium phosphate (1 mol L-1), monopotassium phosphate (1 mol L-1) and aluminum ohloride (5×10-3 mol L-1) were used to investigate the influence of ph on the formation of Nh4-taranakite and K-taranakite in systems with a high Nh4h2PO4 or Kh2PO4 concentration. The experimental data indicated that the reaction products of aluminum with Nh4h2PO4 or Kh2PO4 changed with the ph in the systems. In a ph range of 2.5 to 10.0, as the ph increased, the products in either ammonium or potassium system followed the sequence: taranakite, amorphous (Nh4, K)2Alh(PO4)2 .4h2O, and then crystalline (Nh4, K)AlPO4Oh.2h2O. however, the ph ranges of the formation of these products in ammonium system were different from potassium system. Nh4-taranakite formed from ph 2.75 to Ph 5.75, whereas K-taranakite formed in the ph range of 3.00 to 5.00. From the theoretical calculation by a computer program (GEOChEm version 2.0), Nh4-taranakite and K-taranakite could form at the ph from 1.50 to 8.30 and from 1.25 to 8.45,respectively. These ph ranges were much wider than the experimental results. The difference between the experimental data and theoretical data was attributed to the lack of kinetic data and/or the incompleteness and inaccuracy of the thermodynamic data in the data base of the program. The Ph ranges of the formation of the taranakites indicated that the taranakites could exist in the immediate vicinity of phosphate fertilizer zone as reaction products of phosphate fertilizers with soils, especially acidic soils, resulting in the fixation of not only phosphate but also nitrogen and/or potassium in soils.

关键词： ammonium ph phosphate fertilizer potassium taranakite

Velocity and thermal slip effects on mhD convective radiative two-phase flows in an asymmetric non-uniform channel

在线全文

学校读者我要写书评

暂无评论

Propulsion and Power Research 2021年第2期10卷 169-179页

作者： B.mallikarjuna S.h.C.V.Subba Bhatta S.Ramprasad Department of mathematics B.M.S.College of EngineeringBangaloreAffiliated to VTUBelgaumKarnatakaIndia Department of mathematics M.S.Ramaiah Institute of TechnologyBangaloreAffiliated to VTUBelgaumKarnatakaIndia

This paper aims to examine the influence of thermal radiation on magnetohydrodynamics(mhD)convective two-phase flows through the asymmetric divergent channel under first-order velocity and thermal slip *** transformations are used to nondimensionalize the governed partial differential equations and then solved them numerically.A grid-independent test is done to check the consistency of the numerical method and then validated with existing published results in a limiting *** graphical illustrations are provided to explain the impacts of various emerging parameters on flow *** enhancement in particle velocity is observed with an increment in the velocity slip *** the temperature slip parameter improves a decrement in the fluid as well as particle temperature is *** increment in radiation parameter augments fluid *** type of flow has multifarious range applications like fluidized beds,gas cooling systems,polishing heart valves and internal cavities,etc.

关键词： Particulate suspension Two phase flows heat transfer Thermal radiation Divergent channel

Preparation of crystalline mg(Oh)2 nanopowder from serpentinite mineral

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of mining Science and Technology 2018年第3期28卷 499-503页

作者： V. Sirota V. Selemenev m. Kovaleva I. Pavlenko K. mamunin V. Dokalov m. Yapryntsev Belgorod State National Research University Belgorod 308015 Russia Voronezh State University Voronezh 394006 Russia Belgorod State Technological University named after V.G. Shoukhov Russia

In this paper we describe a route to produce crystalline mg（Oh）2 nanopowders from serpentinite ore distributed in the halilovskiy array （Russia, Orenburg region）. An efficient extraction route consisting of treatment on serpentinite in 40% hNO3 at 80 ℃followed by Nh4Oh titration for mg（Oh）2 precipitation was demonstrated. In this study, crystalline mg（Oh）2 nanopowders have been synthesized by solvothermal reaction method using （mg（NO3）2·6h2O） which were obtained from serpentinite, Nh4Oh as a precipitator, and hydroxyethylated nonylphenol as surface-active substance. microstructure and phase composition of samples were investigated employing scanning electron microscopy （SEm） and transmission electron microscopy （TEm）, X-ray phase analysis （XRD）, and inductively coupled plasma optical emission spectroscopy （ICP-OES）. XRD reveals that mg（Oh）2 nanopowder with high purity has the brucite structure. It was found that crystalline mg（Oh）2 nanopowders exclusively consist of lamellar-like structures and the sizes of mg（Oh）2 are 30-265 nm length or width.

关键词： Serpentinite Nitric acid leaching magnesium hydroxide Solvothermal reaction method Crystalline mg(Oh)2 nanopowder

Physico-mechanical Properties of Composite Briquettes from Corncob and Rice husk

在线全文

学校读者我要写书评

暂无评论

Journal of Bioresources and Bioproducts 2019年第3期4卷 25-31页

作者： h A AJImOTOKAN S E IBITOYE J K ODUSOTE O A ADESOYE P O OmONIYI Department of mechanical Engineering University of IlorinIlorinNigeria Department of materials and metallurgical Engineering University of IlorinIlorinNigeria

Densification of agricultural residues into briquettes as the alternative renewable feedstock can improve their physico-mechanical and storage properties as solid *** paper presents the physico-mechanical properties of the composite briquettes made from corncob and rice *** samples of corncob and rice husk were collected,sorted and pulverised into fines of 0.25,1.00 and 1.75 mm particle *** fines were blended at mixing ratios of 80꞉20,70꞉30,60꞉40,and 50꞉50,bonded with 5%starch on weight percentage basis and compressed at compaction pressures of 25,50,and 65 kPa to produce the briquette *** briquette made from 80:20 ratio of corncob to rice husk,0.25 mm particle size and 65 kPa pressure exhibited the highest compressive strength of 111 kN/m2 and the least of 39 kN/m^(2) from briquette with 50꞉50 ratio of corncob to rice husk,1.75 mm particle size and 25 kPa *** briquette made from 50꞉50 ratio of corncob to rice husk,0.25 mm particle size and 65 kPa pressure had the highest water resistance capacity,and the least from briquette of 80꞉20 ratio of corncob to rice husk,1.75 mm particle size and 25 kPa *** resulting physico-mechanical qualities of the produced corncob and rice husk briquettes suggested that they could be used as the solid fuels for domestic and industrial applications.

关键词： composite briquette compressive strength relaxation ratio durability corncob rice husk

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

金属毒性研究(Ⅰ)

中国有色金属学报 2001年第6期11卷 960-965页

作者：阮建明 m.h.Grant 黄伯云中南大学粉末冶金国家重点实验室长沙410083 Bioengineering Unit Strathclyde University In Glasgow

采用体外细胞培养模式 ,通过测定细胞碱式磷酸酶 (ALP)活性及细胞四甲基偶氮砜 (mTT)还原能力 ,对构成金属和合金生物材料的金属离子 (Al,Ni,Cr ,V ,Ag)的毒性进行了定量评估 ,探讨了金属离子或原子对人体组织的毒害和腐蚀作用。结果表... 详细信息

采用体外细胞培养模式 ,通过测定细胞碱式磷酸酶 (ALP)活性及细胞四甲基偶氮砜 (mTT)还原能力 ,对构成金属和合金生物材料的金属离子 (Al,Ni,Cr ,V ,Ag)的毒性进行了定量评估 ,探讨了金属离子或原子对人体组织的毒害和腐蚀作用。结果表明微量六价铬离子表现出强烈的细胞毒性。当溶液离子度高于 10 0 μmol/L时 ,钒和镍亦表现强烈毒性。银离子和三价铬离子浓度高于 5 0 0 μmol/L后表现毒性。构成老年痴呆病成因的金属铝离子的毒性具有双向性。

关键词：生物材料金属毒性细胞分子生物学

Comment on ＇Electronic Properties of Red P-Type T12S5 Single Crystals＇

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2007年第6期24卷 1786-1786页

作者： m. Cankurtaran h.Celik Department of Physics Faculty of Engineering Hacettepe University Beytepe 06800 Ankara ~1~rkey

Recently, Gamal et al. [Chin. Phys. Left. 22 （2005） 1530] reported the results of electrical conductivity, hall effect and thermoelectric measurements on p-type T12S5 single crystals. From the experimental data for the temperature dependence of differential thermoelectric power, G amal et al. determined the values of 2.66 × 10^-41 kg and 2.50 × 10^-41 kg, respectively, for the effective masses of electrons and holes in p-type T12S5, which are about ten orders of magnitude smaller than the free electron mass （9.11 × 10^-31 kg）. We argue that the anomalously small values obtained for the effective mass of charge carriers in T12S5 have no physical significance.

关键词：

migration of Cations and Anions in Amorphous Polymer Electrolytes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

复旦学报（自然科学版） 2007年第5期46卷 669-页

作者： N.A.Stolwijk S.h.Obeidi m.Wiencierz Institute of materials Physics University of Muenster

1 Results Polymer electrolytes are used as ion conductors in batteries and fuel *** systems consist of a polymer matrix complexing an inorganic salt and are fully amorphous at the temperatures of *** cations and anions are mobile and contribute to charge *** studies on polymer electrolytes use the electrical conductivity to characterize the ion ***,conductivity measurements cannot discriminate between cations and *** paper reports some recent results fr...

关键词： polyether NaI tracer diffusion conductivity single ions ion pairs

Beamforming and Angle-of-Arrival Estimation of Square Planar Antenna Array

在线全文

学校读者我要写书评

暂无评论

Open Journal of Antennas and Propagation 2016年第2期4卷 13-23页

作者： R. Elsamnty A. m. Attiya E. A. F. Abdallah A. h. Ammar Electrical Engineering Department Al-Azhar University Cairo Egypt microwave Engineering Department Electronics Research Institute Giza Egypt microstrip Engineering Department Electronics Research Institute Giza Egypt

This paper presents a dual-band planar antenna array for ISm band applications (2.4 Ghz and 2.45 Ghz). This antenna is proposed for indoor applications and enables adaptive beamforming and angle of arrival (AOA) estimation. An adaptive beamforming algorithm is applied for a planar antenna array, which is able to steer its main beam and nulls in azimuth and elevation planes over a wide frequency band. Planar antenna array operates as a spatial filter in 3D space, processing the received signals with weighting schemes. A planar antenna array is designed for AOA estimation in azimuth and elevation planes by using mUltiple SIgnal Classification (mUSIC) based on subspace algorithm. The Base Station (BS) equipped with this planar antenna is preferred to be at the center position on the room ceiling to cover all sectors of the room. It is designed to use four directional triangular elements arranged to form a square planar antenna array. Planar antenna with four elliptical slotted triangular elements (PAFESTE) is used to obtain optimal directivity in four directions in azimuth plane with specific orientation of 30? in elevation plane. It is characterized by half power beamwidth in elevation plane of about 60? and half power beamwidth in azimuth plane of about 90?.

关键词： Indoor Communications Antenna Array Directional Planar Antenna Angle of Arrival Estimation Adaptive Beamforming