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Coverage analysis of cache-enabled small cell networks with stochastic geometry methods

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The Journal of China Universities of Posts and Telecommunications 2016年第6期23卷 41-46页

作者： Zhang qi Teng Yinglei Liu Mengting Song mei School of Electronic Engineering Beijing University of Posts and Telecommunications

Caching popular content in the storage of small cells is deemed as an efficient way to decrease latency, offload backhaul and satisfy user＇s demands. In order to investigate the performance of cache-enabled small cell networks, coverage probability is studied in both single-point transmission and cooperative multipoint（Co MP） transmission scenarios. Meanwhile, the caching distribution modeled as Zipf and uniform distribution are both considered. Assuming that small base stations（SBSs） are distributed as a homogeneous Poisson point process（HPPP）, the closed-form expressions of coverage probability are derived in different transmission cases. Simulation results show that Co MP transmission achieves a higher coverage probability than that of single-point transmission. Furthermore, Zipf distribution-based caching is more preferable than uniform distribution-based caching in terms of coverage probability.

关键词： caching coverage probability single-point transmission Co MP transmission stochastic geometry

Improved taylor-series location algorithm for cooperation networks

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The Journal of China Universities of Posts and Telecommunications 2007年第2期14卷 38-44页

作者： LIU Jun CUI qi-mei TAO Xiao-feng Key Laboratory of Ubiquitous Wireless Communication Beijing University of Posts and Telecommunications Beijing 100876 China

This article presents an iterative algorithm for estimating the location of the destination mobile station （DS） when some extra mobile stations around the DS are involved in and assist the base stations to complete the localization process. The proposed method is based on the taylor-series （TS） method and jointly estimates both the DS and the extra mobile stations, named reference mobile station （RS） in this article, positions simultaneously. Moreover, the time-differential-of-arrival （TDOA） measurements between DS and pairs of RSs are obtained by ultra-wide-band （UWB） signal, which is adept in accurate ranging application. According to the theoretic analysis, the Cramer-Rao lower bound （CRLB） of the modified TS algorithm reduces significantly. The actual performance, under a given simulation scenario, is enhanced by 25% at best.

关键词： UWB CRLB TS TDOA least-square (LS)

Feature Designed Growth of 3D Flower-like SiO2 Growing on Polyethyleneimine Modified CaCO3 Microparticles

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Chinese Journal of Chemical Physics 2012年第6期25卷 687-690,I0004页

作者： Xin-mei Zheng Yan-xing qi Gong-xuan Lu Lanzhou Institute of Chemical Physics Chinese Academy of Science Lanzhou 730000 China

We report on the ability to create complex 3D flower-like SiO2 in vitro via CaCO3 micropar- icles supported by polyethyleneimine mediated biosilicification under experimentally altered chemical influences. The morphology, structure, composition of the product have been inves- tigated with the X-ray photoelectron spectrum, scanning electron microscope, transmission electron microscope, and energy-dispersive spectroscopy. Tile overall morphologies could be controlled to shift from a characteristic network of flower-like silica sphere to a sheet-like structure by adjusting physical adsorption of different amount of polyethyleneimine onto the surface of the CaCO3 microparticles.

关键词： 3D flower-like SiO2 Polyethyleneimine CaCO3 Biomimetic pattern

Fast generation of W state via superadiabatic-based shortcut in circuit quantum electrodynamics

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Chinese Physics B 2021年第3期30卷 61-67页

作者： Xue-mei Wang An-qi Zhang Peng Xu Sheng-mei Zhao Institute of Signal Processing and Transmission Nanjing University of Posts and TelecommunicationsNanjing 210003China

We propose a scheme to fast prepare the three-qubit W state via superadiabatic-based shortcuts in a circuit quantumelectrodynamics (circuit QED) system. We derive the effective Hamiltonian to suppress the unwanted transitions betweendifferent eigenstates by counterdiabatic driving, and obtain the W state with high-fidelity based on the superadiabaticpassage. The numerical simulation results demonstrate that the proposed scheme can accelerate the evolution, and is moreefficient than that with the adiabatic passage. In addition, the proposed scheme is robust to the decoherence caused by theresonator decay and qubit relaxation, and does not need additional parameters, which could be feasible in experiment.

关键词： W state superadiabatic-based shortcut circuit quantum electrodynamics

Recent Advances in Organic Electrochemical C-H Functionalization

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Chinese Journal of Chemistry 2018年第4期36卷 338-352页

作者： qi-Liang Yang Ping Fan Tian-Sheng mei State Key Laboratory of Organometallic Chemistry Center for Excellence in Molecular Synthesis Shanghai Institute of Organic Chemistry Chinese Academy of Sciences 345 Lingling Lu Shanghai 200032 China Key Laboratory for Advanced Materials and Institute of Fine Chemicals School of Chemistry & Molecular Engineering East China University of Science and Technology 130 Meilong Road Shanghai 200237 China

Organic electrochemistry has a rich history in organic synthesis and has been considered as a promising alternative to traditional chemical oxidants and reductants because it obviates the use of stoichiometric amount of dangerous and toxic reagents. In particular, the electrochemical C-H bonds functionalization is one of the most desirable approaches for the construction of carbon-carbon （C-C） and carbon-heteroatom （C-X） bonds. This review summarizes the substantial progress made in the last few years in C-H functionalization via organic electrochemistry. It is divided into sections on C-C, C-N, C-O, C-S, C-Halogen and C-P bond formation.

关键词： organic electrochemistry C-H functionalization carbon-carbon bond formation carbon-heteroatom bond formation

Rapid Hydrothermal Synthesis of Submillimeter Ultralong Flexible Hydroxyapatite Fiber Using Different pH Regulators

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Acta Metallurgica Sinica(English Letters) 2016年第7期29卷 609-613页

作者： mei-li qi Gui-yong Xiao Yu-peng Lu Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationShandong University School of Materials Science and Engineering Shandong University

Hydroxyapatite fiber （HAF） was fabricated via a one-step hydrothermal route by using urea （CA）, acetamide （AA） and propanamide （PA） as pH regulators, respectively, and the reaction time was only 0.5 h. The HAF synthesized by CA as the pH regulator was agglomerated with irregular morphology, while using AA or PA as the pH regulator, the HAF was composed of well-dispersed fibers with lengths larger than 200 pm. Two different morphologies form mainly due to the different hydrolysis rates of the pH regulators. Most of the fibers synthesized by the three pH regulators showed curving appearance, implying their outstanding flexibility. The technique in this paper allows the rapid formation of flexible HAF and may have wider applications in the restorations and reinforcement composites.

关键词： Hydroxyapatite Fiber Hydrothermal PH regulators

Characterization and analysis of DLC films with different thickness deposited by RF magnetron PECVD

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Rare Metals 2012年第2期31卷 198-203页

作者： Huang, Yujie Wang, qi Wang, mei Fei, Zhenyi Li, Musen

Diamond-like carbon (DLC) films have excellent mechanical and chemical properties similar to those of crystalline diamond giving them wide applications as protective coatings. So far, a variety of methods are employed to deposit DLC films. In this study, DLC films with different thicknesses were deposited on Si and glass substrates using RF magnetron PECVD method with C 4 H 10 as carbon source. The bonding microstructure, surface morphology and tribological properties at different growing stages of the DLC films were tested. Raman spectra were deconvoluted into D peak at about 1370 cm 1 and G peak around 1590 cm 1 , indicating typical features of the DLC films. A linear relationship between the film thickness and the deposition time was found, revealing that the required film thickness may be obtained by the appropriate tune of the deposition time. The concentration of sp 3 and sp 2 carbon atoms in the DLC films was measured by XPS spectra. As the films grew, the sp 3 carbon atoms decreased while sp 2 atoms increased. Surface morphology of the DLC films clearly showed that the films were composed of spherical carbon clusters, which tended to congregate as the deposition time increased. The friction coefficient of the films was very low and an increase was also found with the increase of film thickness corresponding to the results of XPS spectra. The scratch test proved that there was good bonding between the DLC films and the substrates.

关键词： DLC films radio frequency magnetron PECVD characterization thickness

Pulmonary sarcoidosis:A novel sequelae of drug reaction with eosinophilia and systemic symptoms:A case report

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World Journal of Clinical Cases 2022年第35期10卷 13074-13080页

作者： Yu-qi Hu Chen-Yang lv Ai Cui Department of Pulmonary and Critical Care Medicine Beijing Chao-Yang HospitalCapital Medical UniversityBeijing 100020China Department of Pulmonary and Critical Care Medicine The First Hospital of Fangshan DistrictBeijing 102499China

BACKGROUND Drug reaction with eosinophilia and systemic symptoms(DRESS)syndrome is an uncommon yet serious adverse drug hypersensitivity reaction with the presentations including rash,fever,lymphadenopathy,and internal organ *** is a systematic granulomatous disease with unknown *** herein report a case of pulmonary sarcoidosis secondary to allopurinol-induced *** SUMMARY A 37-year-old man with a history of hyperuricemia was treated with allopurinol for three weeks at a total dose of 7000 milligrams before developing symptoms including anorexia,fever,erythematous rash,and elevated *** patient was diagnosed with DRESS and was treated with prednisone for 6 mo until all the symptoms completely *** months later,the patient presented again because of a progressively worsening dry *** chest computed tomography images showed bilateral lung parenchyma involvement with lymph node enlargement,which was confirmed to be nonnecrotizing granuloma by pathological *** on radiologic and pathological findings,he was diagnosed with sarcoidosis and was restarted on treatment with prednisone,which was continued for another 6 *** of chest imaging revealed complete resolution of parenchymal lung lesions and a significant reduction in the size of the mediastinal and hilar lymph *** a 6-month follow-up of completion of treatment,the patient's clinical condition remained stable with no clinical evidence of *** This is the first case in which pulmonary sarcoidosis developed as a late complication of allopurinol-induced *** case indicated that the autoimmune reaction of DRESS may play an important role in the pathogenesis of sarcoidosis.

关键词： Pulmonary sarcoidosis Drug reaction with eosinophilia and systemic symptoms Autoimmune sequelae Allopurinol Case report

Endoscopic magnetic compression stricturoplasty for congenital esophageal stenosis:A case report

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World Journal of Clinical Cases 2022年第33期10卷 12313-12318页

作者： Shi-qi Liu Yi lv Rui-Xue Luo Department of Nursing The Medical CollegeXijing UniversityXi’an 710123Shaanxi ProvinceChina Department of Hepatobiliary Surgery The First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061Shaanxi ProvinceChina The Corrosion&Protection Research Lab Northwest Institute for Nonferrous Metal ResearchXi’an 710016Shaanxi ProvinceChina

BACKGROUND Congenital esophageal stenosis(CES)is a rare malformation of the digestive *** dilation and thoracotomy have been the main treatments for ***,there is no well-defined management *** compression stricturoplasty(MCS)has been used in refractory esophageal stricture in children after esophageal *** SUMMARY We describe the first case of MCS for CES in one female child *** child(aged 3 years and 1 mo)was admitted due to frequent vomiting and choking after eating complementary food since 7 mo *** and gastroendoscopy showed that there was stenosis in the lower esophagus,suggesting a diagnosis of *** patient did not receive any treatment for esophageal stricture including surgery or endoscopic dilation procedures before *** procedure was smoothly conducted without *** 24 mo after MCS,durable esophageal patency without dysphagia was *** MCS may serve as an alternative and efficient method for patients with CES.

关键词： Congenital esophageal stenosis Magnetic compression stricturoplasty Endoscopy Case report