检索结果-南通市图书馆

Origin of major ions in monthly rainfall events at the Bamenda Highlands, north West Cameroon

Journal of Environmental Sciences 2014年第4期26卷 801-809页

作者： Mengnjo J. Wirmvem Takeshi Ohba Wilson y. Fantong Samuel n. Ay.nghe Jonathan n. Hogarh Justice y. Suila Asobo nkengmatia E. Asaah Seigo Ooki Gregory Tanyileke Joseph V. Hell Department of Chemistry School of Science Tokai University Hiratsuka 259-1211 Japan Institute of Geological and Mining Research Yaounde Cameroon Department of Environmental Science Faculty of Science University of Buea Buea Cameroon Department of Environmental Science Kwame Nkrumah University of Science & Technology Kumasi Ghana G.B.H.S. Atiela Nkwen Bamenda Cameroon Department of Earth and Planetary Sciences Tokyo Institute of Technology Tokyo 152-8551 Japan

Rainwater characteristics can reveal emissions from various anthropogenic and natural sources into the atmosphere. The physico-chemical characteristics of 44 monthly rainfall events （collected between January and December 2012） from 4 weather stations （Bamenda, ndop plain, ndawara and Kumbo） in the Bamenda Highlands （BH） were investigated. The purpose was to determine the sources of chemical species, their seasonal inputs and suitability of the rainwater for drinking. The mean pH of 5 indicated the slightly acidic nature of the rainwater. Average total dissolved solids （TDS） were low （6.7 mg/L）, characteristic of unpolluted atmospheric moisture/air. Major ion concentrations （mg/L） were low and in the order K＋〉 Ca2＋〉 Mg2~ 〉 na＋ for cations and nO3 〉〉 HCO3 〉 SO] 〉 CI- 〉 PO3- 〉 F- for anions. The average rainwater in the area was mixed Ca-Mg-SO4-CI water type. The CI-/na＋ ratio （1.04） was comparable to that of seawater （1.16）, an indication that n a＋ and CI originated mainly from marine （Atlantic Ocean） aerosols. High enrichments of Ca2＋, Mg2＋ and SO2- to na＋ ratios relative to seawater ratios （constituting 44% of the total ions） demonstrated their terrigenous origin, mainly from Saharan and Sahelian arid dusts. The K＋/na＋ ratio （2.24）, which was similar to tropical vegetation ash （2.38）, and nO3 was essentially from biomass burning. Light （〈 100 mm） pre-monsoon and post-monsoon convective rains were enriched in major ions than the heavy （〉 100 mm） monsoon rains, indicating a high contribution of major ions during the low convective showers. Despite the acidic nature, the TDS and major ion concentrations classified the rainwater as potable based on the WHO guidelines.

关键词： rainwater chemistry tropical atmosphere drinking-water Bamenda Highlands Cameroon

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Approximate solutions of Klein-Gordon equation with improved Manning-Rosen potential in D-dimensions using SUSyQM

引用

Chinese Physics B 2014年第12期23卷 38-43页

作者： A.n.Ikot H.Hassanabadi H.P.Obong y.E.Chad Umoren C.n.Isonguyo B.H.yazarloo Department of Physics University of Port HarcourtChoba P M B5323 Port Harcourt Nigeria Department of Basic Sciences Shahrood Branch Islamic Azad UniversityShahrood Iran Theoretical Physics Group Department of Physics University of Uyo-NigeriaNigeria

In this paper, we present solutions of the Klein–Gordon equation for the improved Manning–Rosen potential for arbitrary l state in d-dimensions using the supersymmetric shape invariance method. We obtained the energy levels and the corresponding wave functions expressed in terms of Jacobi polynomial in a closed form for arbitrary l state. We also calculate the oscillator strength for the potential.

关键词： Klein–Gordon equation improved Manning–Rosen potential supersymmetric quantum mechanics(SUSyQM)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

PHySICAL SIMULATIOn BASED InTELLIGEnT SySTEM FOR THE PREDICTIOn OF SHEET METAL DRAWInG CAPABILITy

引用

Acta Metallurgica Sinica(English Letters) 2000年第2期13卷 451-458页

作者： D.Lv D.n.He X.J.Bao y.Q.Zhang X.y.Ruan J.L.Cheng J.y.Jiang national Die&Mold CAD Engineering Research Center Shanghai Jiaotong UniversityShanghai 200030China Shanghai Volkswagen Automotive Company Limited Shanghai 201805China

With the combination of a new theoretical formula, physical simulation experiments, the technology of artificial neural network and database, an intelligent system for the prediction of sheet metal drawing capability is constructed for the first time. A modified criterion for sheet metal drawing capability is proposed in this paper, namely, the Technological Limiting Drawing Ratio, TLDR = f(R, n, s, t, F, μ,r_d,r_p…). Based on the studies of other scholars, a new formula is derived to predict the TLDR in this paper. Then a series of orthogonal physical simulation experiments are designed to investigate the effect of technological parameters on the TLDR, and the results are analyzed in the paper. Then the predicting system is constructed with the combination of the theoretical formula, orthogonal experiments, the technology of artifocial neural network and database. The predicted results show good agreements with experimental data, so it can be used to avoid the blindness in the selection of sheet metal before stamping. The system operates under the Windows operating system, and it supports the mechanism of Client/Server as well as Intranet, so the system has high engineering value.

关键词： TLDR theoretical analysis physical simulation orthogonal experiments neural network database predicting system

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of microstructures on superplasticity of Al-11%Si alloy

引用

中国有色金属学会会刊：英文版 2007年第3期17卷 509-513页

作者：江静华马爱斌 n. SAITO A. WATAZU 林萍华 y. nISHIDA Department of Materials Science and Engineering Hohai University national Institute of Advanced Industrial Science and Technology 2266-98 Anagahora Shimoshidami Moriyama-ku Nago ya 463-8560 Japan

Three kinds of Al-11%Si (mass fraction) alloy samples with different processes were produced to investigate the effect of microstructures on its superplasticity. Among them, the as-ECAP sample pressed 16 passes has ultrafine grains (300 nm) and the finest secondary particles. The ECAP-T6 sample, with ECAP 16 passes followed by T6 treatment, has fine secondary particles (3 μm) but the largest grains (8 μm). Contrarily, the T6-ECAP sample, with T6 treatment followed by ECAP 16 passes, has ultrafine grains and the large secondary particles (7 μm). The tensile testing results show that the as-ECAP sample exhibits superplasticity at high strain rate of 5.75×10-1 s-1 due to its fine secondary particles and ultrafine grains. The ECAP-T6 sample, however, does not exhibit superplasticity at the same high strain rate of 5.75×10-1 s-1 because it has relatively large secondary particles and large grains. Remarkably, the T6-ECAP sample does not have superplasticity even at the lower strain rate of 1.15×10-1 s-1, attributing to its comparatively large secondary particles. When most secondary particles are larger than 7 μm, the high strain rate superplasticity could not be obtained even if this sample has ultrafine grains.

关键词：硅铝合金微结构粒子超塑性能

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Graphene Oxide-Based Q-Switched Erbium-Doped Fiber Laser

引用

Chinese Physics Letters 2013年第2期30卷 124-127页

作者： y.K.yap n.M.Huang S.W.Harun H.Ahmad Photonics Research Centre Department of PhysicsFaculty of ScienceUniversity of Malaya50603 Kuala LumpurMalaysia Low Dimensional Materials Research Centre Department of PhysicsFaculty of ScienceUniversity of Malaya50603 Kuala LumpurMalaysia Department of Electrical Engineering Faculty of EngineeringUniversity of Malaya50603 Kuala LumpurMalaysia nanotechnology Research Alliance Universiti Teknologi Malaysia81310 UTMJohore BahruJohor Darul TakzimMalaysia

We demonstrate a pulsed ring erbium-doped fiber laser based on graphene oxide(GO),employ.ng a simplified Hummer's method to synthesize the GO via chemical oxidation of graphite flakes at room *** dipping a fiber ferrule end face onto the GO suspension,GO is successfully coated onto the end face,making it a simple saturable absorption device.A stable Q-switched pulsed fiber laser is achieved with a low pump threshold of 9.5 mW at 980 *** pulse repetition rate ranges from 16.0 to 57.0 *** pulse width and the pulse energy are studied and discussed.

关键词： temperature. fiber pulse

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of Reactivity of Quick Lime on the Properties of Hydrated Lime Sorbent for SO_2 Removal

引用

Journal of Materials Science & Technology 2009年第3期25卷 329-332页

作者： H.G. Shin H. Kim y.n. Kim H.S. Lee Department of Materials Science and Engineering Seoul National University Material Analysis Team Korea Testing Laboratory School of Materials Science and Engineering Pusan National University

The hydration of quick lime and the sulfation of hydrated lime were carried out for verification of relationship between the reactivity of quick lime and the properties of hydrated lime as a sorbent. The effect of reactivity of quick lime was investigated with the change of calcination temperature and time. Results obtained showed that the temperature rise during the hydration of quick limes varied from 31 to 69℃ with the variation of calcination temperature and time. The specific surface area and the sulfation ability of hydrated lime prepared by hydration of quick lime showed a proportional relationship with the reactivity of quick lime. The hydrated lime which was prepared by hydration of quick lime calcined at 1100℃ had the highest reactivity and showed 41.53 m^2/g of the specific surface area, 0.16 cm^3/g of the pore volume and 87% of the removal efficiency for SO2 removal,

关键词： Reactivity Quick lime Hydrated lime Calcination Hydration Sorbent

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Electron Spin Resonance Studies of Mn^2＋ in Freshwater Snail Shells： Pomacea Canaliculata Lamarck and Fossilized Snail Shell

引用

Chinese Physics Letters 2005年第7期22卷 1780-1783页

作者： n.Udomkan S.Meejoo P.Limsuwan P.Winotai y.Chaimanee DepartmentofChemistry FacultyofScienceMahidolUniversityRamaVIRoadBangkok10400_Thailand DepartmentofPhysics FacultyofScienceKingMongkut'sUniversityofTechnologyThonburiPrachautidRoadBangkok10140Thailand paleontologySection GeologicalSurveyDivisionDepartmentofMineralResourcesRamaVIRoadBangkok10400Thailand DepartmentofPhysics FacultyofScienceKingMongkut'sUniversityofTechnologyThonburiPrachautidRoadBangkok10140Thailand//846/227BangmodPrachautid44ThungkruBangkok10140Thailand

We study paramagnetic Mn2+ ions present in the nowadays shells of univalve freshwater snails of Pomacea canaliculata lamarck (PCL) and the fossilized freshwater snail (FFS), Viviparus. All these shells are abundant in Thailand. The PCL shells were ground into fine powder. A set of seven samples were then separately annealed for 2h in air atmosphere at different annealing temperatures while the FFS powder was characterized as-received. The PCL shells mainly consist of aragonite and a fraction of calcite. The heat treatments of the PCL powder samples at temperature higher than 450 degrees C resulted in an irreversible phase transformation from aragonite to calcite. However, it is found that the FFS shell is mainly made of calcite, with a minor fraction of aragonite. The crystal structure of the high-temperature-annealed PCL samples are quite similar to that of FFS, which indicates that the metamorphosis (aragonite → calcite) in the FFS shell had occurred but was not yet completed, although it had remained under the pressure and temperature of the Earth's crusts over millions of years. Our detailed ESR spectral analyses of PCL and FFS show that Mn2+ ions enter the Ca2+ sites during a biomineralization process. Simulated ESR parameters of PCL-500 of Mn2+ at a uniaxial site of calcite are reported. It is surprising to find that the ratio of Mn2+ concentration present in FFS to those in PCL shells evaluated from ESR spectra is as much as 10:1.

关键词： EGAT PCL ESR

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

On the Plasma (ion) Carburized Layer of High nitrogen Austenitic Stainless Steel

引用

材料热处理学报 2004年第5期25卷 375-377页

作者： y. Ueda n. Kanayama K. Ichii T. Oishi H. Miyake Shimane Institute for Industrial Technology 1 Hokuryo-cho Matsue Shimane 690-0816 JapanShimane Institute for Industrial Technology 1 Hokuryo-cho Matsue Shimane 690-0816 JapanFaculty of Engineering Kansai University 3-3-35 Yamate-cho Suita Osaka 564-8680 JapanFaculty of Engineering Kansai University 3-3-35 Yamate-cho Suita Osaka 564-8680 JapanFaculty of Engineering Kansai University 3-3-35 Yamate-cho Suita Osaka 564-8680 Japan

The manganese concentration of austenitic stainless steel decreases from the inner layer towards the surface of the plasma (ion) carburized layer due to the evaporation of manganese from the specimen surface. The carbon concentration in the carburized layer is influenced by alloyed elements such as Cr, ni, Si, and Mo, as well as nitrogen. This study examined the effects of nitrogen on the properties of the carburized layer of high nitrogen stainless steel. Plasma (ion) carburizing was carried out for 14.4 ks at 1303 K in an atmosphere of CH4+H2 gas mixtures under a pressure of 350 Pa. The plasma carburized layer of the high nitrogen stainless steel was thinner than that of an austentric stainless steel containing no nitrogen. This suggested that the nitrogen raised the activity of carbon in the plasma carburized layer, GDOES measurement indicated that the nitrogen level in the layer did not vary after plasma (ion) carburizing.

关键词：等离子渗碳高氮不锈钢奥氏体 GDOES

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Superb Strengthening Effect of net-Like Distributed Amorphous Al_(2)O_(3)on Creep Resistance of(B_(4)C+Al_(2)O_(3))/Al neutron-Absorbing Materials

引用

Acta Metallurgica Sinica(English Letters) 2022年第12期35卷 2007-2013页

作者： y.n.Zan X.Lei J.F.Zhang D.Wang Q.Z.Wang B.L.Xiao Z.y.Ma Key Laboratory of nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China nuclear Equipment Division Beijing Institute of Nuclear EngineeringChina Nuclear Power Engineering Co.LtdBejing 100840China

B4C reinforced Al composites are widely used as neutron absorbing materials(nAMs)due to excellent neutron absorbing efficiency,however,such nAMs exhibit poor high-temperature *** meet the requirement for structure-function integration,nAMs with enhanced high-temperature mechanical properties are *** this work,a novel(B4 C+Al_(2)O_(3))/Al nAM with netlike distribution of Al_(2)O_(3)was fabricated by powder metallurgy method and subjected to high-temperature tensile creep *** was shown that the creep resistance was enhanced by several orders of magnitude via the addition of only2.1 vol.%netlike-distributed Al_(2)O_(3).(B_(4)C+Al_(2)O_(3))/Al exhibited high apparent stress exponents ranging from 16 to 25 and high apparent activation energy of 364 kJ/*** creep behaviour could be rationalized using the substructure-invariant model and its rupture behaviour could be described by the Dobes-Milicka equation.

关键词： neutron absorber material Al matrix composite Tensile creep B_(4)C/Al

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Isovector pairing and particle-number fluctuation effects on the spectroscopic factors of one-proton stripping and one-neutron pick-up reactions in proton-rich nuclei

引用

Chinese Physics C 2018年第8期42卷 137-158页

作者： y.Benbouzid n.H.Allal M.Fellah M.R.Oudih Laboratoire de Physique Theorique-Facultéde Physique-USTHB BP32 El-Alia16111 Bab-Ezzouar-Alger-Algeria

Expressions of the spectroscopic factors（SFs） corresponding to one-particle transfer reactions have been established using a schematic *** expressions have been derived by taking into account the isovector neutron-proton（np） pairing correlations and a particle-number projection in the framework of the generalized SharpBCS（SBCS） *** proposed expressions of the projected wave-functions of odd-mass nuclei have been used for this *** formalism has first been tested using the single-particle energies of the schematic picketfence *** is shown that the np pairing and particle-number fluctuation effects are far from negligible and they depend on the pairing gap parameter *** behavior is not the same when the parent nuclei are even-even or *** dealing with the SFs corresponding to one-proton stripping and one-neutron pick-up reactions in proton-rich nuclei have then been established within the framework of the realistic Woods-Saxon *** is shown that the np pairing effect as well as the particle-number projection effect are important and thus have to be included in future calculations of the SF corresponding to these kinds of reactions.

关键词： neutron-proton pairing particle-number projection spectroscopic factor

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：