检索结果-南通市图书馆

一类含瞬时和非瞬时脉冲的三点边值问题解的存在性和多重性

在线全文

学校读者我要写书评

暂无评论

应用数学 2024年第3期37卷 728-738页

作者：张慧萍姚旺进福建师范大学数学与统计学院福建福州350007 莆田学院福建省金融信息处理重点实验室福建莆田351100

本文研究一类含有瞬时和非瞬时脉冲的二阶p-Laplacian微分方程的三点边值问题.利用变分方法和三临界点定理获得至少一个古典解和至少三个古典解的存在性.

关键词：三点边值问题变分方法三临界点定理

Mesoporous Silica MCM-48 Membrane Synthesized on a Coarse-pore α-Al_2O_3 Ceramic Tube

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2005年第2期21卷 131-133页

作者： LIUChun-yan wangjin-qu InstituteofAdsorptionandinorganicMembrane DalianUniversityofTechnologyDalian116012P.R.Chinas／／FacultyofChemistryandChemicalEngineeringLiaoningNormalUniversityDalian116029P.R.China InstituteofAdsorptionandinorganicMembrane DalianUniversityofTechnologyDalian116012P.R.Chinas

A mesoporous MCM-48 membrane was synthesized on a coarse-pore α-alumina ceramic tube by hydrothermal treatment by using a cationic surfactant as the structure-directing agent under basic conditions. The products were characterized by small-angle X-ray diffraction, SEM measurements and N_2 adsorption experiments. The X-ray diffraction(XRD) results show that the membrane possesses a periodic mesostructure, which is typical for an MCM-48 material. The results of the SEM measurements indicate that MCM-48 grew in the pores of the support and formed a continuous membrane. The N_2 adsorption and desorption isotherms also show that the membrane is a typical mesoporous material with pore channel size of about 2.74 nm.

关键词： Mesoporous membrane MCM-48 Synthesis Alumina support

Synthesis and Crystal Structure of 1-(Trifluoromethyl)-1-(propioloyl)-(E)-3-oxo-(2-thienyl)-(2-naphthylamine)

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2004年第1期23卷 41-43页

作者： wangjin-Ling diNGFeng YUMing MIAOFang-Ming CollegeofChemicalandLifeScience TianjinNormalUniversityTianjin300074ChinaE-mail：wangjinling43@*** CollegeofChemicalandLifeScience TianjinNormalUniversityTianjin300074ChinaDepartmentofEnvironmentandSafetyEngineeringTianjinUniversityofTechnologyTianjin300141China UniversityofTianjinScientificTechnology Tianfin300122China CollegeofChemicalandLifeScience TianjinNormalUniversityTianjin300074China

The title compound has synthesized and its crystal structure was determined by X-ray analysis. The crystal belongs to monoclinic, space group C2/c with a = 10.413(3), b = 16.080(5), c = 19.188(6) ? b = 94.023(7), V = 3205(2) 3, Z = 8, Dc =1.440 g/cm3, F(000) = 1424, m(MoKa) = 0.238 mm-1, S = 0.896, R = 0.0454 and wR = 0.0998 for 1914 observed reflections with I ≥ 2s(I). In the title compound (C18H12F3NOS), the side-chain carbonyl group, the adjacent double bond and the amine N from 2-naphthylamine are essentially coplanar with the largest deviation from this plane being 0.018(2) ?for atom C(3). The dihedral angle between the mean plane and the thienyl ring is 4.24(3)? A strong intramolecular NH…O hydrogen bond (N…O 2.666(3) ?and NH…O 142(3)) was observed, which leads to an enamine tautomer in the crystal.

关键词： TTA 2-naphthylamine synthesis structure

FORCES ON A NEAR-WALL CIRCULAR CYLINDER

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2004年第6期16卷 658-664页

作者： ZHANJing-xia wangjin-jun ZHANGPang-feng FluidMechanicsInstitute BeijingUniversityofAeronauticsandAstronauticsBeijing100083China

The pressure distribution around a near-wall smooth circular cylinder incross-flow was mainly investigated. The experiment was conducted at the sub-critical Reynolds numberranging from 2. 24 · 10~4 to 8. 94 · 10~4, at which the regular vortex separation exists on anisolated circular cylinder. The experimental results indicate that the forces on a circular cylindernear a plane wall are different from those on an isolated circular cylinder. Drag and liftcoefficients of a near-wall circular cylinder strongly depend on gap ratio. The increase of gapratio results in the increase of drag coefficient and the declination of lift coefficient, dragcoefficient ranges from 0. 5 to 1. 0, and lift coefficient from 0. 25 to 0 when gap ratio graduallyincreases from 0 to 1. 0, and then the forces tend to be nearly constant with the increase of gapratio. The attraction between a cylinder and a plane wall, i. e. , downward force, occurs when gapratio lies in certain range. The existence of cylinder changes the pressure gradient on the planewall, and the influence extends to the location where x/D 5. 0 .

关键词： gap ratio static pressure coefficient distribu-tiontlift coefficient dragcoefficient

Microstructure of Ni-Based Self-Fluxing Alloy Sprayed Coating

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2005年第2期12卷 56-59页

作者： wangjin-hua MilanFriesel MagnusWillander RichardWarren ChalmersUniversityofTechnology GoteborgS-41296Sweden PowderMetallurgyAssociationofChinaSteelConstructionSociety Beijing100081China MalmoUniversity MalmoS-20506Sweden

The microstructure of a Ni-based self-fluxing alloy coating produced by an oxygen-acetylene flame spraying Ni-16.5Cr-3.3B-4.7Si-4.4Fe-0.8C system alloy powder onto a common steel substrate was investigated by microanalysis *** phases in the coating were observed by SEM and determined by XEDS X-Ray energy spectrum and X-Ray diffraction ***,some molecular formulas were calculated.

关键词： microstructure sprayed coating self-fluxing alloy superlattice

Dynamic Analysis for Bose-Einstein Condensation in Quantum Cavity

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2005年第5期43卷 900-904页

作者： ZHANGLi WANGCheng LIYan-Min wangjin-Fang SchoolofPhysics NortheastNormalUniversityChangchun130024China／／ChangchunInstituteofOpticsFineMechanicsandPhysicstheChineseAcademyofSciencesChangchun130022China ChangchunInstituteofOptics FineMechanicsandPhysicstheChineseAcademyofSciencesChangchun130022China DepartmentofAppliedMathematics ChangchunTaxationCollegeChangchun130021China SchoolofPhysics NortheastNormalUniversityChangchun130024China

For the two-level atoms system interacting with single-mode active field in a quantum cavity, the dynamics of the Bose-Einstein Condensation (BEC) is analyzed using an ordinary method suggested by authors to solve the system of Schrodinger representation in the Heisenberg representation. The wave function of the atoms is given. The stability factor determining the BEC and the selection rules of the quantum transition are solved.

关键词： Bose-Einstein condensation quantum cavity representation laser cooling

温度对金属微互连结构界面微裂纹扩展连通过程的影响

在线全文

学校读者我要写书评

暂无评论

热加工工艺 2024年第14期53卷 122-126,129页

作者：马文婧王进郭慧吕美妮张宏泽宋宝林广西机器视觉与智能控制重点实验室广西梧州543002 梧州学院电子与信息工程学院广西梧州543002

采用晶体相场方法在纳米尺度下对金属微互连结构界面微裂纹扩展连通过程进行了研究。结果表明:随着温度的升高和演化时间的增加,微裂纹扩展过程中主裂纹长度增大,二次微裂纹数量增多,微裂纹呈“一字形”和“树枝状”生长,微裂纹扩展过... 详细信息

采用晶体相场方法在纳米尺度下对金属微互连结构界面微裂纹扩展连通过程进行了研究。结果表明:随着温度的升高和演化时间的增加,微裂纹扩展过程中主裂纹长度增大,二次微裂纹数量增多,微裂纹呈“一字形”和“树枝状”生长,微裂纹扩展过程中的连通行为逐渐增多。初始缺口形貌为圆形的微裂纹在扩展过程中主裂纹长度和二次微裂纹出现的时间均比初始缺口形貌为矩形的慢。微裂纹扩展长度随着演化时间和温度的增加逐渐增大;微裂纹扩展速率随着温度的增加而增大,但随着演化时间的增加,呈先增加后减小趋势。温度并不改变原子波动周期,不同温度下微裂纹的扩展只取决于原子扩散速率,与原子间距无关。

关键词：微裂纹扩展连通晶体相场方法微观组织演化

RAdiCAL FLOW IN POROUS MEdiA WITH diSPERSION AND ADSORPTION

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2004年第2期16卷 216-219页

作者： LIUCi-qun GUOBai-qi SONGFu-quan wangjin-ying InstituteofPorousFlowMechanics ChineseAcademyofSciencesLangFang065007Chinae-mail：fqsong@sinacom ThecomputationCenterofLanzhou Lanzhou730001China ShanghaiInstituteofAppliedMathematicsandMechanics ShanghaiUniversityShanghai200072China No.1ProductionCompanyofDaQingOilFieldLtd.Co. Daqing163001China

The radical transport of chemical concentration in porous media withdispersion and adsorption was studied in this paper. Using Langmuir''s adsorption model, thenumerical equation of concentration transport was derived. The flows with and without adsorptionwere simulated and analyzed. Comparison of the obtained solution with the known analytical solutionfor flow without adsorption shows the presented numerical method is correct and effective, which canbe used in reservoir engineering.

关键词： flow in porous media simulation dispersion adsorption

Significant influences of TiO_(2)crystal structures on NO_(2)and HONO emissions from the nitrates photolysis

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2021年第4期33卷 198-206页

作者： Wenwen Xu wangjin Yang Chong Han He Yang Xiangxin Xue School of Metallurgy Northeastern UniversityShenyang 110819China

The emissions of NO_(2)and HONO from the KNO_(3)photolysis in the presence of TiO_(2)were measured using a round-shape reactor coupled to a NO_(x)***_(2)played important roles in the emission flux density of NO_(2)(R_(NO_(2)))and HONO(R HONO),depending on crystal structures and mass ratios of TiO_(2).R NO_(2)and R HONO significantly decreased with increasing the rutile and anatase mass ratios from 0 to 8 and 0.5 wt.%,***,with further increasing the anatase mass ratio to 8 wt.%,there was an increase in R_(NO_(2))and R HONO.R NO_(2)on KNO_(3)/TiO_(2)/SiO_(2)had positive correlation with the KNO_(3)mass(1–20 wt.%),irradiation intensity(80–400 W/m^(2))and temperature(278–308 K),while it had the maximum value at the relative humidity(RH)of 55%.R HONO on KNO_(3)/TiO_(2)/SiO_(2)slightly varied with the KNO_(3)mass and temperature,whereas it increased with the irradiation intensity and *** addition,the mechanism for NO_(2)and HONO emissions from the nitrates photolysis and atmospheric implications were discussed.

关键词： TiO_(2) Nitrates Photolysis NO_(2)