检索结果-南通市图书馆

Journal of Wuhan University of Technology(Materials Science) 2015年第1期30卷 47-50页

作者：翁凌 YAN Liwen LI Hongxia xia qianshan LIU Lizhu Key Laboratory of Engineering Dielectrics and Its Application Ministry of Education Harbin University of Science and Technology School of Materials Science and Engineering Harbin University of Science and Technology

A novel core-shell structure Ag@Al2O3 nano-particles were synthesized and doped into polyimide as conductive fillers to prepare the composite films with high dielectric properties and low dielectric loss. The morphology and structures of the Ag@Al2O3 nano-particles were characterized by transmission electron microscopy （TEM）, X-ray diffraction （XRD）, and UV-visible spectroscopy. All the results proved that the Ag@Al2O3 nano-parficles had a typical core-shell structure, for the Ag particles were coated by Al2O3 shell and the average sizes ofAg@Al2O3 particles were between 30 to 150 nm. The as-prepared Ag@Al2O3 nanoparticles were doped into the polyimide with different mass fractions to fabricate the Ag@Al2O3/PI composite films via in-situ polymerization process. SEM analysis of composite films showed that the Ag@Al2O3 nano- particles homogeneously dispersed in polyimide matrix with nanoseale. As dielectric materials for electronic packaging systems, the Ag@Al2O3/PI composites exhibited appropriate mechanical properties and erthaneed dielectric properties, including greatly enhanced dielectric constant and just a slight increase in dielectric loss. These improvements were attributed to the core-shell structure of fillers and their fine dispersion in the PI matrix.

关键词： core-shell structure polyimide nanocomposites dielectrics

Analytical Solutions for an Isotropic Elastic Half-Plane with Complete Surface Effects Subjected to a Concentrated/Uniform Surface Load

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2024年第3期37卷 371-384页

作者： xia-Hui Pan School of Civil Engineering Henan Polytechnic UniversityJiaozuo454003China

Within the context of Gurtin-Murdoch surface elasticity theory,closed-form analytical solutions are derived for an isotropic elastic half-plane subjected to a concentrated/uniform surface *** the effects of residual surface stress and surface elasticity are *** stress function method and Fourier integral transform technique are *** solutions are provided in a compact manner that can easily reduce to special situations that take into account either one surface effect or none at *** results indicate that surface effects generally lower the stress levels and smooth the deformation profiles in the *** elasticity plays a dominant role in the in-plane elastic fields for a tangentially loaded half-plane,while the effect of residual surface stress is fundamentally crucial for the out-of-plane stress and displacement when the half-plane is normally *** the remaining situations,combined effects of surface elasticity and residual surface stress should be *** results for a concentrated surface force serve essentially as fundamental solutions of the Flamant and the half-plane Cerruti problems with surface *** solutions presented in this work may be helpful for understanding the contact behaviors between solids at the nanoscale.

关键词： Surface effects Residual surface stress Surface elasticity Half-plane Analytical solutions

Computational modelling of gas–liquid–solid multiphase free surface flow with and without evaporation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第7期90卷 218-235页

作者： Huihuang xia Marc Kamlah Institute for Applied Materials(IAM) Karlsruhe Institute of Technology(KIT)Hermann-von Helmholtz-Platz 176344 Eggenstein-LeopoldshafenGermany

Gas–liquid–solid multiphase systems are ubiquitous in engineering applications,*** printing,spray drying and *** a numerical framework for modelling these multiphase systems is of great *** improved,resolved computational fluid dynamics-discrete element method(CFD-DEM)framework is developed to model the multiphase free surface flow with and without *** improved capillary force model is developed to compute the capillary interactions for partially floating particles at a free *** well-known benchmark cases,namely drag coefficient calculation,the single sphere settling,and drafting-kissing-tumbling of two particles are conducted to validate the resolved CFD-DEM *** turns out that the resolved CFD-DEM model developed in this paper can accurately calculate the fluid–solid interactions and predict the trajectory of solid particles interacting with the liquid *** demonstrations,namely two particles moving along a free surface when the liquid phase evaporates,and particle transport and accumulations inside an evaporating sessile droplet show the performance of the resolved model.

关键词： Capillary force Discrete element method Liquid bridge Particle transport Resolved CFD-DEM Volume of fluid

Seasonal thermal energy storage using natural structures:GIS-based potential assessment for northern China

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Building Simulation 2024年第4期17卷 561-574页

作者： Yichi Zhang Jianjun xia Midea HVAC Heating&Ventilation Equipment Co. LtdFoshan528311China Building Energy Research Center Tsinghua UniversityBeijing100084China

Seasonal thermal energy storage(STES)allows storing heat for long-term and thus promotes the shifting of waste heat resources from summer to winter to decarbonize the district heating(DH)*** being a promising solution for sustainable energy system,large-scale STES for urban regions is lacking due to the relatively high initial investment and extensive land *** close the gap,this study assesses the potentials of using two naturally available structures for STES,namely valley and ground pit *** on geographical information system(GIS)methods,the available locations are searched from digital elevation model and selected considering several criteria from land uses and construction *** costs of dams to impound the reservoir and the yielded storage capacities are then quantified to guide the choice of suitable *** assessment is conducted for the northern China where DH systems and significant seasonal differences of energy demand *** total,2,273 valley sites and 75 ground pit sites are finally identified with the energy storage capacity of 15.2 billion GJ,which is much larger than the existing DH demand in northern *** results also prove that 682 valley sites can be achieved with a dam cost lower than 20 CNY/m^(3).By conducting sensitivity analysis on the design dam wall height and elevations,the choices of available natural structures are expanded but practical issues about water pressures and constructions are also ***,the identified sites are geographically mapped with nearest urban regions to reveal their roles in the DH *** general,560 urban regions are found with potential STES units and most of them have STES storage capacities larger than their own DH *** novel planning methodology of this study and publicly available datasets create possibilities for the implementations of large-scale STES in urban DH systems.

关键词： seasonal thermal energy storage geographical information system district heating water reservoir

Minimum mass-entransy dissipation profile for one-way isothermal diffusive mass-transfer process with mass-resistance and massleakage

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第8期67卷 2427-2435页

作者： CHEN LinGen xia ShaoJun Institute of Thermal Science and Power Engineering Wuhan Institute of TechnologyWuhan 430205China School of Mechanical Electrical EngineeringWuhan Institute of TechnologyWuhan 430205China School of Power Engineering Naval University of EngineeringWuhan 430033China

As a new concept,mass-entransy is one of the twins in the core of entransy *** can describe mass-transfer ability for masstransfer processes(MTPes),just as thermal-entransy for describing heat-transfer ***,mass-entransy dissipation can be utilized to evaluate the loss of mass-transfer *** mass-entransy dissipation(MMED) is utilized to optimize one-way isothermal diffusive MTPes with mass-leakage and mass-transfer law(g ∝ Δ(c),where c means concentration).For a given net amount of mass-transferred key components at the low-concentration side,optimality-condition for the MMED of isothermal diffusive MTPes is obtained by using the *** of the amount of mass-transferred and mass-leakage on optimal results are analyzed,and the obtained optimization profiles are compared with those for MTP profiles of constant-concentration-difference(c_1-c_2=const) and constant-concentration-ratio(c_1/c_2=const).The product of square of key-component-concentration(KCC) difference between high-and low-concentration sides and inert component concentration at high-concentration side for the MMED of the MTP with no mass-leakage is a constant,and the optimal relationship of the KCCs between high-and low-concentration sides with mass-leakage is significantly different from the *** mass-leakage is relatively small,the MTP with c_1-c_2=const strategy is superior to that with c_1/c_2=const strategy,and the latter is superior to the former with an increase in mass-leakage.A combination of mass-entransy concept,finite-time thermodynamics,and averaged-optimization-method is a meaningful tool for optimizing MTPes.

关键词： diffusive mass-transfer-law mass-leakage one-way isothermal mass-transfer minimum mass-entransy dissipation finite-time thermodynamics averaged-optimization-method

Regional features of pollen R-values in China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2024年第1期67卷 295-308页

作者： Jie xia Jian NI College of Life Sciences Zhejiang Normal UniversityJinhua 321004China Jinhua Mountain Observation and Research Station for Subtropical Forest Ecosystems Jinhua 321004China

Establishing a quantitative relationship between modern pollen and vegetation remains a pivotal but intricate pursuit within the field of Quaternary *** R-value,a well-established and traditional metric characterized by its simplicity and direct applicability,serves to calibrate the nonlinear disparities between surface pollen and modern *** study entails the construction of a comprehensive pollen R-value dataset for China derived from R-values published between 1987 and *** dataset,compiled after rigorous screening,calibration,and standardization processes,encompasses 898 modern pollen sampling sites and 2115 pollen R-value data entries,encapsulating 152 pollen taxa spanning 65 families and 113 *** the extracted R-values yielded the following insights:(1)A macrospatial analysis validates previously established knowledge at a site-specific ***,pollen R-value variations across China are statistically *** two-thirds of pollen taxa exhibit underrepresentation(e.g.,Taxodiaceae,Corylus,Nitraria,Tamarix,Cyperaceae,Poaceae,and Fabaceae),while the remaining one-third display overrepresentation(e.g.,Pinus,Picea,Betula,Ephedra,Chenopodiaceae,and Artemisia).The degree of underrepresentation surpasses that of overrepresentation,and the representation patterns of Castanea,Quercus,Polygonaceae,and Asteraceae are contingent upon vegetation types.(2)Pollen R-values follow distinct spatial distribution patterns within *** the woody vegetation region of eastern China,R-values progressively decline from north to south,correlating with rising temperatures and ***,in herbaceous vegetation regions of northern and western China,R-values decrease from east to west and from northeast to southwest,corresponding to increased ***,pollen R-values manifest variation contingent on pollen taxa,vegetation types,and climatic regions,even differing for the same taxa across varying

关键词： Pollen R-value Modern pollen-vegetation relationship Regional pattern Variability Paleovegetation reconstruction

Cloud-based control systems: towards the control architecture in cloud computing era

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2024年第10期67卷 386-388页

作者： Yuanqing xia School of Automation Beijing Institute of Technology Zhongyuan University of Technology

Era of cloud computing. After Google introduced the concept of “cloud computing”, this paradigm experienced rapid growth and found widespread applications across various industries, establishing itself as one of the... 详细信息

关键词： Cloud computing architecture

“Buckets effect”in the kinetics of electrocatalytic reactions

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第2期89卷 388-396,I0010页

作者： Haowen Cui Yan-xia Chen Hefei National Laboratory for Physical Sciences at Microscale Department of Chemical PhysicsUniversity of Science and Technology of ChinaHefei 230026AnhuiChina

In this study,we systematically investigated the effect of proton concentration on the kinetics of the oxygen reduction reaction(ORR)on Pt(111)in acidic *** results demonstrate a rectangular hyperbolic relationship,i.e.,the ORR current excluding the effect of other variables increases with proton concentration and then tends to a constant *** consider that this is caused by the limitation of ORR kinetics by the trace oxygen concentration in the solution,which determines the upper limit of ORR kinetics.A model of effective concentration is further proposed for rectangular hyperbolic relationships:when the reactant concentration is high enough to reach a critical saturation concentration,the effective reactant concentration will become a constant *** could be due to the limited concentration of a certain reactant for reactions involving more than one reactant or the limited number of active sites available on the *** study provides new insights into the kinetics of electrocatalytic reactions,and it is important for the proper evaluation of catalyst activity and the study of structureperformance relationships.

关键词： Oxygen reduction reaction Kinetics Zero order Rectangular hyperbolic relationship pH effect

Asperuloside Promotes Apoptosis of Cervical Cancer Cells through Endoplasmic Reticulum Stress-Mitochondrial Pathway

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Integrative Medicine 2024年第1期30卷 34-41页

作者： QI Zhi-min WANG xia LIU xia ZHAO Juan Medical Examination Center Hebei Province Hospital of Chinese MedicineShijiazhuang(050011)China Department of Gynaecology and Obstetrics Hebei Province Hospital of Chinese MedicineShijiazhuang(050011)China Experimental Center for Teaching Hebei Medical UniversityShijiazhuang(050017)China

Objective: To investigate the effects of asperuloside on cervical cancer based on endoplasmic reticulum(ER) stress and mitochondrial pathway. Methods: Different doses(12.5–800 μg/mL) of asperuloside were used to treat cervical cancer cell lines Hela and CaSki to calculate the half maximal inhibitory concentration(IC_(50)) of asperuloside. The cell proliferation was analyzed by clone formation assay. Cell apoptosis, intracellular reactive oxygen species(ROS) and mitochondrial membrane potential were determined by flow cytometry. The protein expressions of cleaved-caspase-3, Bcl-2, Bax, Cyt-c, cleaved-caspase-4 and glucose-regulated protein 78(GRP78) were analyzed by Western blot. And the inhibitor of ER stress, 4-phenyl butyric acid(4-PBA) was used to treat cervical cancer cells to further verify the role of ER stress in the apoptosis of cervical cancer cells induced by asperuloside. Results: Asperuloside of 325, 650, and 1300 μg/mL significantly inhibited the proliferation and promoted apoptosis of Hela and CaSki cells(P<0.01). All doses of asperuloside significantly increased intracellular ROS levels, reduced mitochondrial membrane potential, significantly reduced Bcl-2 protein expression level, and increased Bax, Cyt-c, GRP78 and cleaved-caspase-4 expressions(P<0.01). In addition, 10 mmol/L 4-PBA treatment significantly promoted cell proliferation and reduced apoptosis(P<0.05), and 650 μg/mL asperuloside could reverse 4-PBA-induced increased cell proliferation, decreased apoptosis and cleaved-caspase-3,-4 and GRP78 protein expressions(P<0.05). Conclusion: Our study revealed the role of asperuloside in cervical cancer, suggesting that asperuloside promotes apoptosis of cervical cancer cells through ER stress-mitochondrial pathway.

关键词： asperuloside Chinese medicine cervical cancer endoplasmic reticulum stress mitochondrial damage apoptosis

A regularization algorithm of dynamic light scattering for estimating the particle size distribution of dual-substance mixture in water

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第6期89卷 246-257页

作者： Yanghong Wang Ziqiang Meng Zipei Zhang Min xia Li xia Wei Li School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China

Dynamic light scattering(DLS)is a nondestructive,well-established technique for the size characterization of proteins,nanoparticles,polymers,and colloidal ***,current DLS techniques are only applied to particle groups of single composition due to the limitation of their inversion *** this study,we propose a particle size distribution inversion algorithm based on the Tikhnonov regularization method that can be applied to the dual-substance particle *** algorithm retrieves the particle size distributions of two substances,respectively,by taking advantage of their refractive index *** simulation results reveal that the algorithm has excellent accuracy and stability when the scattering angle is 30°.Instead of the original identity matrix,the first-order difference matrix and second-order difference matrix are used as the regular matrix when utilizing the Tikhnonov algorithm,which obviously improves the anti-interference,accuracy,and stability of the ***,the inversion of particle size distribution is carried out at a 0.01%–1%noise level,which shows that the algorithm has an available antinoise ***,experimental particle size measurements for a mixture of polystyrene beads and toner particles demonstrate that the proposed algorithm is superior to the traditional Tikhnonov algorithm in applicability and accuracy.

关键词： Dynamic light scattering Dual-substance mixture Particle sized istribution Tikhnonov regularization