检索结果-南通市图书馆

Solution of time-domain Maxwell equation with PML by using modified Laguerre polynomials

在线全文

学校读者我要写书评

暂无评论

Science in China(Series F) 2008年第5期51卷 550-559页

作者： li lianlin li fang Institute of Electronics Chinese Academy of Sciences Beijing 100080 China

In this work, a stable numerical algorithm proposed by Chung et al. for the time-domain Maxwell equations is generalized. The time-domain Maxwell equations are solved by expressing the transient behaviors in terms of the modified Laguerre polynomials, and then the original equations of the initial value and boundary value can be transformed into a series of problems independent of the time variable. In this case the method of finite difference （FD）, the finite element method （FEM）, the method of moment （MoM）, etc. or the combination of these methods can be used to solve the problems. Finally, a numerical model is provided for the scattering problem with perfect matched layer （PML） by using FD. The comparison between the results of the proposed method and FDTD is presented to verify the proposed new method.

关键词： time-domain Maxwell equations modified Laguerre polynomials boundary value problems

A photometric study of the high-mass-ratio contact binary AV Puppis

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2019年第12期19卷 217-222页

作者： Quan-Wang Han li-fang li Deng-Kai Jiang Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory of the Structure and Evolution of Celestial Objects Chinese Academy of Sciences.Kunming 650216China University of Chinese Academy of Sciences Beijing 100049China

The multi-color photometric light curves for contact binary AV Puppis(AV Pup) in VRcIc bandpasses are presented and analyzed by using the 2013 version of the Wilson-Devinney(W-D) *** solutions suggest that AV Pup is a peculiar A-subtype W UMa contact binary with a high mass ratio(q = m2/m1 = 0.896) and a low fill-out factor(f = 10%). Combining our newly determined times of minimum with those collected from literatures, the orbital period changes of this system are investigated. The O-C analysis indicates that the orbital period of AV Pup is increasing at a rate of d P/dt = 4.83 × 10-7 days yr-1, which can be explained by mass transfer from the less massive component to the more massive one.

关键词： techniques:photometric stars:magnetic field stars:individual:AV Pupis

Absolute physical parameters of three poorly studied detached eclipsing binaries

在线全文

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2021年第1期21卷 220-228页

作者： Dao-Ye Yang li-fang li Quan-Wang Han Yunnan Observatories Chinese Academy of SciencesKunming 650216China Key Laboratory for the Structure and Evolution of Celestial Objects Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Center for Astronomical Mega-Science Chinese Academy of SciencesBeijing 100012China Key Lab of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 10101China School of Physics and Electronics Qiannan Normal University for NationalitiesDuyun 558000China

The photometric and spectroscopic data for three double-lined detached eclipsing binaries were collected from the photometric and spectral *** light and radial velocity curves of each binary system were simultaneously analyzed using Wilson-Devinney(WD)code,and the absolute physical and orbital parameters of these binaries were *** masses of both components of ASASSN-V J063123.82+192341.9 were found to be M1=1.088±0.016 and M20.883±0.016 M⊙;those of ASAS J011416+0426.4 were determined to be M1=0.934±0.046 and M2=0.754±0.043 M⊙;and those of MW Aur were derived to be M1=2.052±0.196 and M21.939±0.193 M⊙.Finally,the evolutionary status of these detached binaries was discussed based on their absolute parameters and the theoretical stellar models.

关键词： stars:binaries:eclipsing stars:fundamental parameters stars:evolution stars:individual:ASASSN-V J063123.82+192341.9,ASAS J011416+0426.4 and MW Aur

The Effect of Method of Constructing the Mass Distribution on Single Stellar Populations

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2005年第4期5卷 371-378页

作者： Feng-Hui Zhang li-fang li Zhan-Wen Han National Astronomical Observatories Yunnan Observatory Chinese Academy of SciencesKunming 650011

We use two methods of constructing the initial mass distribution, the traditional way and Monte Carlo simulation, to obtain integrated U - B, B - V,V-R and V-I colours and absorption-line indices defined by the lick Observatory image dissector scanner （referred to as lick/IDS）, for instantaneous burst solarmetallicity single stellar populations with ages in the range 1-15Gyr. We find that the evolutionary curves of all colours obtained by the traditional method are smoother than those by Monte Carlo simulation, that the U- B and B- V colours obtained by the two methods agree with one another, while the V - R and V - I colours by the traditional method are bluer than those by Monte Carlo simulation.A comparison of the lick/IDS absorption-line indices shows that the variations in all the indices by the traditional method are smoother than that for the Monte Carlo simulation, and that all the indices except for TiO1 and TiO2 are consistent with those for the Monte Carlo simulation.

关键词： star: evolution - galaxies: star clusters- galaxies: stellar content

Coded overlapped code division multiplexing system with Turbo product structure

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2010年第2期17卷 25-29页

作者： ZHOU Su-hua fang li li Dao-ben School of Information and Telecommunication Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

Coded overlapped code division multiplexing system with Turbo product structure （TPC-OVCDM） is introduced, and trellis coded modulation （TCM） code is employed as error correcting code for uncoded overlapped code division multiplexing （OVCDM） system. In such a scheme, row code and column code are TCM and OVCDM spreading code, respectively. Data bits are only encoded directly by TCM and transformed into a matrix. Each column of this matrix is then permuted by symbol interleaver before being encoded by OVCDM spreading code. During iterative decoding process in the receiver, two constituent decoders use symbol by symbol BCJR algorithm in the log domain. The order of decoding two sub-codes is determined by the encoding order. The proportion of TCM coding and OVCDM coding affects system performance. For fixed coding structure and symbol interleaver, the performance of TPC-OVCDM systems of different proportions of additive white Gaussian noise （AWGN） channel have been simulated. The results show that TPC-OVCDM system of reasonable proportion can achieve significant coding gain, compared with uncoded OVCDM system under the condition of same spectral efficiency at bit error rate （BER） level of 10^-5.

关键词： overlapped code division multiplexing trellis coded modulation TPC-OVCDM iterative decoding

liNK BETWEEN OXIDATIVE STRESS AND INSUliN RESISTANCE

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Sciences Journal 2007年第4期22卷 254-259页

作者： Lan-fang li Jian li Key Laboratory of Geriatrics of Ministry of Health Beijing Institute of Geriatrics Beijing Hospital Ministry of Health Beijing 100730

Many studies on oxidative stress,insulin resistance,and antioxidant treatment have shown that increased oxidative stress may accelerate the development of diabetic complications through the excessive glucose and free fatty acids metabolism in diabetic and insulin-resistant *** pathogenic mechanisms such as insulin receptor substrate phosphorylation are involved in insulin resistance induced by oxidative *** antioxidant treatments can show benefits in animal models of diabetes mellitus and insulin ***,negative evidence from large clinical trials suggests that new and more powerful antioxidants need to be studied to demonstrate whether antioxidants can be effective in treating diabetic ***,it appears that oxidative stress is only one of the factors contributing to diabetic ***,antioxidant treatment would most likely be more effective if it were coupled with other treatments for diabetic complications.

关键词： insulin resistance oxidative stress diabetes mellitus

Perioperative anesthesia management in pediatric liver transplant recipient with atrial septal defect:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2022年第29期10卷 10638-10646页

作者： Lan liu Pei Chen li-li fang li-Na Yu Department of Anesthesiology The Second Affiliated Hospital of Zhejiang University School of MedicineHangzhou 310009Zhejiang ProvinceChina Department of Anesthesiology Hangzhou Women's HospitalHangzhou 310008Zhejiang ProvinceChina

BACKGROUND Preoperative conditions in pediatric liver transplant recipients are understandably *** with adults,children have lesser compensatory abilities and demand greater precision during procedural *** the setting of endstage liver disease,the heightened perioperative risk of coexistent cardiovascular pathology may impact graft survival as *** for anesthesia and perioperative management are thus more rigorous,calling for individualized treatments that reflect specific cardiovascular constraints and proposed surgical *** SUMMARY Reports of perioperative anesthesia management and liver transplant prognostication in pediatric patients with concurrent atrial septal defects are ***,we detail the course of liver transplantation in a child with dual afflictions,focusing on perioperative anesthesia management and the important contributions of the anesthesiologist(pre-and perioperatively) to a positive therapeutic outcome,despite the clinical hurdles *** Children with atrial septal defects bear substantially more than customary perioperative risk during orthotopic liver transplants,given their compromised cardiopulmonary reserves and functional *** preoperative cardiovascular assessments,including use of agitated-saline contrast echocardiography(to characterize intracardiac shunting) and multidisciplinary deliberation,may offer insights into structural cardiac pathophysiologic effects and transplantrelated hemodynamic changes that impact new *** the same time,active and effective monitoring and other measures should be taken to maintain hemodynamic stability in the perioperative period,avoid entry of bubbles into the circulation,and ease congestion in newly grafted *** efforts are crucial for transplantation success and graft survival.

关键词： Pediatric liver transplant Atrial septal defect Anesthesia Case report

Design, Syntheses and Biological Activities of Novel Anthranilic Diamide Insecticides Containing N-Pyridylpyrazole

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

Chemical Research in Chinese Universities 2013年第1期29卷 51-56页

作者： ZHAO Yu li Yong-qiang XIONG li-xia XU li-ping PENG li-na li fang li Zheng-ming National Pesticidal Engineering Centre(Tianjin) State Key Laboratory of Elemento-organic Chemistry Nankai University Tianjin 300071 P. R. China

In search of environmentally benign insecticides with high activity, low toxicity and low residue, a series of novel anthranilic diamide derivatives containing N-pyridylpyrazole was designed and synthesized. All the compounds were characterized by H NMR spectroscopy and elemental analysis. The single crystal structure of com pound 8j was determined by X-ray diffraction. The insecticidal activities of the new compounds were evaluated. The results show that some compounds exhibited moderate insecticidal activities against Lepidoptera pests. Among this series of compounds, compounds 80 and 8p showed 100% larvicidal activity against Mythimna separate Walker, Plutella xylostella linnaeus and Laphygma exigua Hubner at a test concentration of 200 mg/kg, which is equal to the commercial chlorantraniliprole.

关键词： Anthranilic diamide Ryanodine receptor Insecticidal activity

Newtonian limit of Einstein equation with a cosmological constant

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

Chinese Physics C 2024年第10期48卷 264-274页

作者： li-fang li Zhoujian Cao Xiaokai He Institute of Mechanics Chinese Academy of SciencesBeijing 100190China Institute of Applied Mathematics Academy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUCASHangzhou 310024China School of Mathematics and Statistics Hunan First Normal UniversityChangsha 410205China

Traditionally,the cosmological constant has been viewed as dark energy that mimics matter with negative *** that matter with negative energy provides a repulsive force,which fundamentally differs from typical gravitational forces,it has been believed that the cosmological constant effectively contributes a repulsive ***,it is important to note that the concept of gravitational force is valid only within the framework of Newtonian *** this study,we demonstrate that the traditional understanding of the gravitational force contributed by the cosmological constant is not entirely *** approach involves investigating the Newtonian limit of the Einstein equation with a cosmological *** subtleties involved in this analysis are discussed in ***,we find that the effect of the cosmological constant on Newtonian gravity is an attractive force rather than a repulsive one for ordinary *** expected,this corrective force is negligibly ***,our findings may offer a way to distinguish between dark energy and the cosmological constant,as one contributes a repulsive force while the other contributes an attractive force.

关键词： cosmological constant dark matter Einstein equation Newtonian limit dark energy