检索结果-南通市图书馆

Additive Schwarz Preconditioners with Minimal Overlap for Triangular Spectral Elements

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2013年第2期13卷 411-427页

作者： yuen-yick Kwan Center for Computational Science Tulane UniversityNewOrleansLA 70118USA

The additive Schwarz preconditioner with minimal overlap is extended to triangular spectral elements(TSEM).Themethod is a generalization of the corresponding method in tensorial quadrilateral spectral elements(QSEM).The proposed preconditioners are based on partitioning the domain into overlapping subdomains,solving local problems on these subdomains and solving an additional coarse problem associated with the subdomain *** results of numerical experiments show that the proposed preconditioner are robust with respect to the number of elements and are more efficient than the preconditioners with generous overlaps.

关键词： Spectral elements additive Schwarz

frequency dependence in the emission from subpulse drifting pulsars

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2021年第9期21卷 153-162页

作者： Xiao-Hong Han Rai yuen Xinjiang Astronomical Observatory Chinese Academy of SciencesUrumqi 830011China Key Laboratory of Radio Astronomy Chinese Academy of SciencesUrumqi 830011China SIfA School of PhysicsUniversity of SydneySydneyNSW 2006Australia

We investigate relations in the emission properties as revealed by drifting subpulses detected at different observing frequencies based on the method that incorporates the rotating carousels in pulsar magnetospheres of multiple emission *** emission state is associated with particular emission properties as determined by the drifting subpulses at a particular frequency,and different emission states obtained at different frequencies reveal the variation of emission properties across the emission *** method allows the determination of the essential radio emission properties such as the relative emission height,subpulse number,charge density and the plasma flow relative to corotation in an emission region for a particular *** apply the method to seven pulsars that exhibit subpulse drifting along single drift-band at 326 MHz and 1429 *** results show that drifting subpulses observed at different frequencies correspond to particular emission states suggesting that the pulsar emission properties are frequency *** show that emission follows the frequency-to-radius mapping for pulsars with obliquity angle?30°regardless of the sign and magnitude of the *** pulsars with long rotation periods in our sample,the circulation time for the plasma to revolve once around the magnetosphere relative to corotation increases as the rotation period increases at both frequencies,but exhibits irregularity for pulsars with short rotation *** results suggest that evolution of the obliquity angles in subpulse drifting pulsars is from large to small,and the emission region tends to be’thicker’in younger pulsars.

关键词： radiation mechanisms:non-thermal pulsar:general

q-Besselian frames in Banach Spaces

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2007年第9期23卷 1707-1718页

作者： yu can ZHU Department of Mathematics Fuzhou University Fuzhou 350002 P. R. China

In this paper, we introduce the concepts of q-Besselian frame and （p, σ）-near Riesz basis in a Banach space, where a is a finite subset of positive integers and 1/p＋1/q = 1 with p 〉 1, q 〉 1, and determine the relations among q-frame, p-Riesz basis, q-Besselian frame and （p, σ）-near Riesz basis in a Banach space. We also give some sufficient and necessary conditions on a q-Besselian frame for a Banach space. In particular, we prove reconstruction formulas for Banach spaces X and X^＊ that if {xn}n=1^∞ C X is a q-Besselian frame for X, then there exists a p-Besselian frame {y＆＊}n=1^∞ belong to X^＊ for X^＊ such that x = ∑n=1^∞ yn^＊（x）xn for all x ∈ X, and x^＊ =∑n=1^∞ x^＊（xn）yn^＊ for all x^＊ ∈ X^＊. Lastly, we consider the stability of a q-Besselian frame for the Banach space X under perturbation. Some results of J. R. Holub, P. G. Casazza, O. Christensen and others in Hilbert spaces are extended to Banach spaces.

关键词： q-frame p-Riesz basis q-Besselian frame (p σ)-near Riesz basis

Mechanical stretching of 3D hydrogels for neural stem cell differentiation

在线全文

学校读者我要写书评

暂无评论

Bio-Design and Manufacturing 2022年第4期5卷 714-728页

作者： Quanjing Mei Ho-yin yuen Xin Zhao Department of Biomedical Engineering The Hong Kong Polytechnic UniversityHung HomHong KongChina

While it is known that mechanical dynamics are influential in neural differentiation for critical processes like neurogenesis or neurodegeneration, studies on neural stem cell therapies usually focus on biochemical interactions rather than mechanical aspects, frequently resulting in low efficacy and unfulfilled potential. Therefore, current studies are attempting to elucidate the effect of mechanical stimulus on neural performance using conventional two-dimensional(2D) planar substrates. yet, these2D substrates fail to capture the defining three-dimensional(3D) characteristics of the in vivo neural stem cell *** complete this research gap, we synthesized a series of soft and elastic 3D hydrogels to mimic the neural tissue mechanical environment for 3D cell culture, using long-chain polyethylene glycol diacrylate(PEGDA) and gelatin-methacryloyl(Gel MA).By varying the concentration of the polymer, we obtained biomimicking hydrogels with a tensile modulus as low as 10 k Pa and a compressive modulus as low as 0.8 k Pa. The in vitro results demonstrated that Gel MA-PEGDA hydrogels have the high biocompatibility required to support neural cell growth, proliferation, and differentiation, as well as neurite outgrowth. We then studied the effect of mechanical stretching on the behaviors of neural cells and observed that mechanical stretching could significantly enhance neurite extension and axon elongation. In addition, the neurites were more directionally oriented to the stretching direction. Immunocytochemistry and relative gene expression data also suggested that mechanical tension could upregulate the expression of neural differentiation protein and genes, including GfAP and βIII-Tubulin. Overall, this study shows that in addition to the specific mechanical properties of Gel MA-PEGDA that improve neural differentiation towards specific lineages, hydrogel stretching is also a potentially attractive strategy to improve the therapeutic outcomes of neural stem cel

关键词： Mechanical property Tensile stretching Hydrogels Neural differentiation 3D cell culture

‘Radicalize’the Performance of Perovskite Solar Cells with Radical Compounds

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2023年第2期39卷 176-186页

作者： WANG can GAO Peng State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou350002P.R.China Laboratory for Advanced functional Materials Xiamen Institute of Rare Earth MaterialsHaixi InstituteChinese Academy of SciencesXiamen361021P.R.China Xiamen Key Laboratory of Rare Earth Photoelectric functional Materials Xiamen Institute of Rare Earth MaterialsChinese Academy of SciencesXiamen361021P.R.China University of Chinese Academy of Sciences Beijing100049P.R.China

Perovskite solar cells(PSCs)have attracted tremendous attention due to their outstanding performance within a short *** molecules with unpaired single electrons have been widely used in energy-related fields,such as organic light-emitting diodes(OLEDs),organic field-effect transistors(OfETs),organic and dye-sensitized solar cells,batteries,thermoelectric conversion devices,***,as far as we know,there has never been a systemic collection and analysis of the application of radical molecules in ***,we summarized the role of the radical molecule on perovskite(passivate trap defects,enhance oxygen stability and make perovskite band-bending)and charge transport layer(improve conductivity and mobility,enhance oxygen stability,modulate work function and decrease by-product generating).Meanwhile,future directions of making full use of radical molecules in improving the performances of PSCs were envisioned.

关键词： Radical molecule Perovskite solar cell Unpaired single electron Modulate W_(f)

Vibrational Resonance in an Overdamped System with a Sextic Double-Well Potential

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics Letters 2011年第9期28卷 50-53页

作者： WANG can-Jun Nonlinear Research Institute Baoji University of Arts and SciencesBaoji 721007

The phenomenon of vibrational resonance(VR)in an overdamped system with a sextic double-well potential under the excitation of two different periodic signals is *** approximate analytical expression of the resonance amplitude Q at the low−frequencyωis *** VR is observed,and the values of B(the amplitude of the high−frequency signal)andΩ(the frequency of the high−frequency signal)at which VR occurs are ***,the relationship between B andΩis *** theoretical predictions are found to be in good agreement with the numerical results.

关键词： damped vibrational excitation

Highly Improved Creep Resistance in Polypropylene Through Thermally Reduced Graphene Oxide and Its Creep Lifetime Prediction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2024年第2期42卷 256-266,I0010页

作者： can-can Zhang Jun-Long yang ya-Jiang Huang Guang-Xian Li College of Polymer Science and Engineering State Key Laboratory of Polymer Materials Engineering of ChinaSichuan UniversityChengdu610065China

Polypropylene(PP) exhibits suboptimal creep resistance due to the presence of methyl groups on its main chain, leading to irregular chain segment distribution, diminished inter-chain interaction, and crystallinity. This structural feature causes chain slippage in PP under stress,significantly constraining its service lifetime. In this study, thermally reduced graphene oxide(TrGO) nanosheets were incorporated into the PP matrix, yielding a nanocomposite with exceptional creep resistance performance. Results demonstrated that at a stress of 25 MPa, a 2.0 wt% TrGO content could enhance the creep failure lifetime of PP by 21.5 times compared to neat PP. Rheology, transmission electron microscopy(TEM),and scanning electron microscopy(SEM) characterization techniques were employed to analyze the mechanism of TrGO's influence on PP's creep behavior. It was observed that when TrGO content exceeded 1.0 wt%, an effective particle network structure formed within the PP matrix. This homogeneously dispersed TrGO-formed particle network structure restricted the migration and rearrangement of PP molecular chains, enabling prolonged stress resistance without structural failure. By combining the time-strain superposition method with the critical failure strain as a criterion, generalized creep compliance curves for PP and its composites were established, facilitating the prediction of material creep failure lifetimes, with a strong agreement between experimental and predicted lifetime values. This research proposes a novel strategy aimed at developing polypropylene materials and products with enhanced long-term stability and durability, thus extending service life, reducing failure risk, and broadening their potential across various application domains.

关键词： Thermally reduced graphene oxide Polypropylene Creep failure and lifetime prediction

Performance of the combination of decarbonisation policy instruments and implications for carbon neutrality in China

在线全文

学校读者我要写书评

暂无评论

Advances in Climate Change Research 2022年第6期13卷 923-937页

作者： Lin fU can WANG School of Environment Tsinghua UniversityBeijing 100084China National Center for Climate Change Strategy and International Cooperation Beijing 100035China

Decarbonisation is a complex systemic issue that involves multiple market ***,the integrated application of multiple policy instruments is *** study used the fuzzy-set qualitative comparative analysis(fsQCA)method to explore the causality relationship between decarbonisation policies with reference to the Intergovernmental Panel on Climate Change(IPCC)and the decoupling elasticity of Tapio from a configuration *** found that taxation and regulation are the critical drivers of decoupling,while information and public goods and services are *** decoupled policy mixes were tabled,each focusing on a)taxation,b)taxation and economic instruments,and c)trading system and *** contrast,the execution of information and voluntary instruments,as well as the non-implementation of the tax,are essential to *** combinations that are negative for decoupling were also introduced:a)trade and economic incentives,b)trade,information and voluntary instruments,and c)information,public goods and services,and voluntary *** most valuable policy mix for China is the implementation of taxes,trade,economic and regulations with the provision of auxiliary decarbonised information and public goods and *** following processes are involved:a)integrate regulations with economic policies for more flexibility;b)introduce the carbon tax and a tax rebate policy to complement the carbon market policy based on research into the feasibility and cost-effectiveness;c)provide information and public services mainly on the consumption side;and d)recommend voluntary policies for innovative *** the basis of more cases and a configuration perspective,this study offers various policy mixes that are conducive or not to decoupling and suggestions for optimising China’s decarbonisation *** also offered a way to measure the intensity of the decarbonisation policy with respect to the carbon emission structure of sect

关键词： Policy instrument Qualitative comparative analysis Configuration Tapio decoupling

Contralateral hemopneumothorax after penetrating thoracic trauma:A case report

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2021年第15期9卷 3773-3778页

作者： Mehlikaİşcan Thoracic Surgery Department Gebze Fatih State HospitalKocaeli 41400GebzeTurkey

BACKGROUND Trauma is the leading cause of death in young adults up to the age of 45 *** is a frequent consequence of penetrating thoracic trauma,and is usually associated with pneumothorax and *** arterial bleeding or intrathoracic hemorrhage occurs after penetrating thoracic trauma,and uncontrolled bleeding is the main cause of *** SUMMARy In this case report,a patient who developed a right hemopneumothorax after penetrating thoracic trauma was examined.A 19-year-old male patient,who was brought to the emergency room with a penetrating stab injury to the posterior of the left hemithorax,was diagnosed with a right hemopneumothorax after physical examination and thoracic *** tube thoracostomy was performed as the initial *** control was achieved with right posterolateral thoracotomy in the patient,who developed massive hemorrhage after 1 h and hemodynamic *** patient recovered and was discharged on the fourth postoperative *** Contralateral hemopneumothorax that accounts for 30%of thoracic traumas and can be encountered in penetrating thoracic traumas requiring major surgery in 15-30%of cases was emphasized and the contralateral development mechanism was addressed.

关键词： Chest tube Contralateral hemopneumothorax Penetrating thoracic trauma Thoracotomy Thoracic surgery Tube thoracostomy Case report