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Performance of degree distribution based HARQ scheme for LDPC-coded OFDM system

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The Journal of China Universities of Posts and Telecommunications 2009年第1期16卷 47-50页

作者： li Xue-hua CAO Yi-qing li zhen-song YANG Da-cheng Communication Engineering Department Beijing Information Science and Technology University Beijing 100101 China Wireless Theories and Technologies Lab (WT&T) Beijing University of Posts and Telecommunications Beijing 100876 China

This article studies the degree distribution property of low density parity check （LDPC） codes by Gaussian approximation （GA） and presents an efficient hybrid automatic repeat quest （HARQ） scheme for LDPC-coded orthogonal frequency division multiplexing （OFDM） system. In the scheme, the important bits with large degrees have high retransmission priorities and are mapped to the sub-carriers with better channel quality indicator （CQI） levels in the OFDM system. The new scheme provides more protection to the bits with large degrees and thus contributes more to the decoding process by offering more transmission power. In this way the system performance would be improved. The statistics and simulation results also prove the new scheme.

关键词： LDPC codes HARQ degree distribution GA OFDM

Precise immobilization of metal single atoms into a porphyrinic metal-organic framework for an efficient alkene hydrosilylation

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Nano Research 2024年第7期17卷 5914-5921页

作者： Chun-Ying Chen Qi-Jie Mo Fu-zhen li Hai-li song li Zhang MOE Laboratory of Bioinorganic and Synthetic Chemistry Lehn Institute of Functional MaterialsSchool of ChemistrySun Yat-Sen UniversityGuangzhou 510006China

Alkene hydrosilylation is one of the most concise and atom-economical methods to synthesize organosilicon ***,we reported the precise immobilization of metal single atoms(M-SAs;M=Ru,Rh,Ir,Pd,Pt,and Au)into a porphyrinic metalorganic framework(MOF)of PCN-222(PCN=porous coordination network),and then applied the resultant MOF composites of M-SAs@PCN-222 to alkene *** solvent-free conditions,Pt-SAs@PCN-222 displayed an especially high catalytic efficiency with the turnover frequency up to 119 s−1 and the maximum turnover number of 906,250 at room *** and theoretical studies revealed that there existed strong interactions between Pt-SAs@PCN-222 and the substrates,which helped to condense the substrates in the cavities of the porous *** density functional theory calculations and molecular dynamics simulations disclosed that PCN-222 could transfer electrons to Pt-SAs to enhance the silane oxidative addition and drive the reaction to proceed smoothly via Chalk–Harrod pathway.

关键词： alkene hydrosilylation single atom catalysts metal-organic frameworks precision chemistry synergistic catalysis

Anion competition for li^(+)solvated coordination environments in poly(1,3 dioxolane)electrolyte to enable high-voltage lithium metal solid-state batteries

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Journal of Energy Chemistry 2024年第9期96卷 633-641页

作者： Qiujun Wang Yanqiang Ma Xiaomeng Jia Di Zhang Zhaojin li Huilan Sun Qujiang Sun Bo Wang li-zhen Fan Hebei Key Laboratory of Flexible Functional Materials School of Materials Science and EngineeringHebei University of Science and TechnologyShijiazhuang 050000HebeiChina Beijing Advanced Innovation Center for Materials Genome Engineering Institute of Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China

Gel-based polymer electrolytes are limited by the polarity of the residual solvent,which restricts the coupling-breaking behaviour during li^(+)conduction,resulting in the li^(+)transport kinetics being greatly ***,we designed anion competitive gel polymer electrolyte(ACPE)by introducing lithium difluoro(oxalato)borate(liDFOB)anion into the 1,3-dioxolane(DOL)in situ polymerisation *** enhances the ionic dipole interaction between li^(+)and the solvent molecules and synergizes with li^(+)across the solvation site of the polymer ethylene oxide(EO)unit,combination that greatly improves the li^(+)transport *** a result,ACPE exhibits 1.12 mS cm^(−1)ionic conductivity and 0.75 li^(+)transfer number at room ***,this intra-polymer solvation sheath allows preferential desolvation of DFOB−,which contributes to the formation of kinetically stable anion-derived interphase and effectively mitigates side *** results demonstrate that the assembled li||NCM622 solid-state battery exhibits lifespan of over 300 cycles with average Coulombic efficiency of 98.8%and capacity retention of 80.3%.This study introduces a novel approach for ion migration and interface design,paving the way for high-safety and high-energy-density batteries.

关键词： li-metal batteries Poly(1,3-dioxolane) In situ polymerization Solid-state polymer electrolytes Anion competition

Designed imidazole-based supramolecular catalysts for accelerating oxidation/hydrolysis cascade reactions

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Nano Research 2024年第6期17卷 4916-4923页

作者： Yuanxi liu Wenjie Xu Shichao Xu Haifeng Wu Baoli Zhang li song zhen-Gang Wang State Key Laboratory of Organic-Inorganic Composites Key Lab of Biomedical Materials of Natural Macromolecules(Ministry of Education)Beijing Laboratory of Biomedical MaterialsCollege of Materials Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China National Synchrotron Radiation Laboratory CAS Center for Excellence in NanoscienceUniversity of Science and Technology of ChinaHefei 230029China

Reconstructing enzymatic active sites presents a significant challenge due to the intricacies involved in achieving enzyme-like scaffold folding and spatial arrangement of essential functional *** is also a growing interest in building biocatalytic networks,wherein multiple enzymatic active sites are localized within a single artificial system,allowing for cascaded *** this work,we report the self-assembly of imidazole or its derivatives with fluorenylmethyloxycarbonyl-modified histidine and Cu2+to fabricate a supramolecular catalyst,which possesses catechol oxidase-like dicopper center with multiple imidazole as the coordination *** electron microscopy,low-temperature X-band continuous-wave electron paramagnetic resonance,K-edge X-ray absorption spectra/the extended X-ray absorption fine structure analysis,and density functional theory modeling were used for the structural characterization of the *** phenol derivatives and the dissolved oxygen were used as the substrates,with the addition of 4-aminoantipyrine to generate a red adduct with a maximum absorbance at 510 nm,for obtaining time-dependent absorbance change curves and estimating the *** results reveal that the addition of imidazole synergistically accelerates the oxidative activity about 10-fold and the hydrolysis activity about 14-fold than fluorenylmethyloxycarbonyl modified-histidine/Cu2+.The supramolecular nanoassembly also exhibits the ability to catalyze oxidation/hydrolysis cascade reactions,converting 2′,7′-dichlorofluorescin diacetate into 2′,7′-*** process can be regulated through the methylation of the imidazole component at various *** work may contribute to the design of advanced biomimetic catalysts,and shed light on early structural models of the active sites of the primitive copper-dependent enzymes.

关键词： enzyme mimic self-assembly supramolecular catalyst cascade reactions

Large contributions of emission reductions and meteorological conditions to the abatement of PM_(2.5)in Beijing during the 24th Winter Olympic Games in 2022

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Journal of Environmental Sciences 2024年第2期136卷 172-188页

作者： Yaping Jiang Shaocai Yu Xue Chen Yibo Zhang Mengying li zhen li Zhe song Pengfei li Xiaoye Zhang Eric lichtfouse Daniel Rosenfeld Key Laboratory of Environmental Remediation and Ecological Health Ministry of EducationResearch Center for Air Pollution and HealthCollege of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058China College of Science and Technology Hebei Agricultural UniversityBaoding 071000China Chinese Academy of Meteorological Sciences China Meteorological AdministrationBeijing 100081China Aix-Marseille Univ CNRSColl FranceCNRSIRDINRAEEuropole Mediterraneen de l’ArboisAvenue Louis Philibert13100 Aix en ProvenceFrance Xi’an Jiaotong University State Key Laboratory of Multiphase Flow in Power EngineeringXi’an 710049China Institute of Earth Sciences The Hebrew University of JerusalemJerusalemIsrael

To guarantee the blue skies for the 2022 Winter Olympics held in Beijing and Zhangjiakou from February 4 to 20,Beijing and its surrounding areas adopted a series of emission control *** provides an opportunity to determine the impacts of large-scale temporary control measures on the air quality in Beijing during this special ***,we applied the WRF-CMAQ model to quantify the contributions of emission reduction measures and meteorological *** show that meteorological conditions in 2022 decreased PM_(2.5)in Beijing by 6.9 and 11.8μg/m^(3)relative to 2021 under the scenarios with and without emission reductions,*** emission reduction measures implemented in Beijing and seven neighboring provinces resulted in an average decrease of 13.0μg/m^(3)(-41.2%)in PM_(2.5)in *** the entire period,local emission reductions contributed more to good air quality in Beijing than nonlocal emission *** the emission reduction scenario,local,controlled regions,other regions,and boundary conditions contributed 47.7%,42.0%,5.3%,and 5.0%to the PM_(2.5)concentrations in Beijing,*** results indicate that during the cleaning period with the air masses from the northwest,the abatements of PM_(2.5)were mainly caused by local emission ***,during the potential pollution period with the air masses from the east-northeast and west-southwest,the abatements of PM_(2.5)were caused by both local and nonlocal emission reductions almost *** implies that regional coordinated prevention and control strategies need to be arranged scientifically and rationally when heavy pollution events are forecasted.

关键词： PM_(2.5) WRF-CMAQ Meteorological conditions Emission reductions Winter Olympic games

Whole-genome analysis reveals distinct adaptation signatures to diverse environments in Chinese domestic pigs

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Journal of Animal Science and Biotechnology 2024年第5期15卷 1866-1880页

作者： zhen Wang Bangmin song Jianyu Yao Xingzheng li Yan Zhang Zhonglin Tang Guoqiang Yi Shenzhen Branch Guangdong Laboratory of Lingnan Modern AgricultureKey Laboratory of Livestock and Poultry Multi‑Omics of MARAAgricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhen 518124China Kunpeng Institute of Modern Agriculture at Foshan Agricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesFoshan 528226China School of life Sciences Henan UniversityKaifeng 475004China Shenzhen Research Institute of Henan University Shenzhen 518000China State Key Laboratory of Pharmaceutical Biotechnology The University of Hong KongHong Kong SARChina Key Laboratory of Tropical Animal Breeding and Disease Research Institute of Animal Science and Veterinary MedicineHainan Academy of Agricultural SciencesHaikou 571100China Bama Yao Autonomous County Rural Revitalization Research Institute Bama 547500China

Background Long-term natural and artificial selection has resulted in many genetic footprints within the genomes of pig breeds across distinct agroecological ***,the mechanisms by which these signatures contribute to phenotypic diversity and facilitate environmental adaptation remain *** Here,we leveraged whole-genome sequencing data from 82 individuals from 6 domestic pig breeds originating in tropical,high-altitude,and frigid *** genetic analysis suggested that habitat isolation significantly shaped the genetic diversity and contributed to population stratification in local Chinese pig *** of selection signals revealed regions under selection for adaptation in tropical(55.5 Mb),high-altitude(43.6 Mb),and frigid(17.72 Mb)*** potential functions of the selective sweep regions were linked to certain complex traits that might play critical roles in different geographic environments,including fat coverage in frigid environments and blood indicators in tropical and high-altitude *** genes under selection were significantly enriched in biological pathways involved in environmental *** pathways included blood circulation,protein degradation,and inflammation for adaptation to tropical environments;heart and lung development,hypoxia response,and DNA damage repair for high-altitude adaptation;and thermogenesis,cold-induced vasodilation(CIVD),and the cell cycle for adaptation to frigid *** examining the chromatin state of the selection signatures,we identified the lung and ileum as two candidate functional tissues for environmental ***,we identified a mutation(chr1:G246,175,129A)in the cis-regulatory region of ABCA1 as a plausible promising variant for adaptation to tropical *** In this study,we conducted a genome-wide exploration of the genetic mechanisms underlying the adaptability of local Chinese pig breeds to tropical,high-altitude

关键词： Environmental adaptation Local Chinese breeds Pig Population genetics Selection signals Whole-genome resequencing

Configuring single-layer MXene nanosheet onto natural wood fiber via C-Ti-C covalent bonds for high-stability li-S batteries

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Journal of Energy Chemistry 2024年第8期95卷 701-711,I0016页

作者： Yangyang Chen Yu liao Ying Wu Lei li zhen Zhang Sha Luo Yiqiang Wu Yan Qing College of Materials Science and Technology Central South University of Forestry and TechnologyChangsha 410004HunanChina

lithium-sulfur batteries(LSBs)are considered promising candidates for next-generation battery technologies owing to their outstanding theoretical energy density and ***,the low conductivity and polysulfide shuttling effect of S cathodes severely hamper the practical performance of ***,in situ-generated single layer MXene nanosheet/hierarchical porous carbonized wood fiber(MX/PCWF)composites are prepared via a nonhazardous eutectic activation strategy coupled with pyrolysis-induced gas *** unique architecture,wherein single layer MXene nanosheets are constructed on carbonized wood fiber walls,ensures rapid polysulfide conversion and continuous electron transfer for redox *** C-Ti-C bonds formed between MXene and PCWF can considerably expedite the conversion of polysulfides,effectively suppressing the shuttle *** impressive capacity of 1301.1 m A h g^(-1)at 0.5 C accompanied by remarkable stability is attained with the MX/PCWF host,as evidenced by the capacity maintenance of 722.6 m A h g^(-1)after 500 ***,the MX/PCWF/S cathode can still deliver a high capacity of 886.8 m A h g^(-1)at a high S loading of 5.6 mg cm^(-2).The construction of two-dimensional MXenes on natural wood fiber walls offers a competitive edge over S-based cathode materials and demonstrates a novel strategy for developing high-performance batteries.

关键词： lithium-sulfur batteries S cathodes MXene nanosheets Wood fiber C-Ti-C bonds

Enhanced thermoelectric properties of Cu_(3)SbSe_(4)-based materials by synergistic modulation of carrier concentration and phonon scattering

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Journal of Materiomics 2024年第2期10卷 339-347页

作者： Sitong Wei zhen Ji Wenhao li Shuqi zheng Qing Wang Zhiliang li Lu Yu Sitong Luo Weiyu song College of New Energy and Materials China University of PetroleumBeijing102249China College of Science China University of PetroleumBeijing102249China Key Laboratory of High-precision Computation and Application of Quantum Field Theory of Hebei Province College of Physics Science and TechnologyHebei UniversityBaoding071002China

Cu_(3)SbSe_(4),a copper-based sulfide free of rare earth elements,has received extensive attention in ther-moelectric ***,its low carrier concentration restricts its widespread *** this study,a microwave-assisted solution synthesis method was used to produce samples of Cu_(3)SbSe_(4),which enabled the formation of CuSe in situ and increased the *** the use of first-principles cal-culations,structural analysis,and performance evaluation,it was found that CuSe can enhance the carrier concentration and that induced nano-defects have a positive effect on reducing the lattice thermal ***,doping with Sn decreases the band gap of the system and moves the Fermi level into the valence band,increasing the carrier concentration to 1.15×10^(-20)cm^(-3).Finally,the zT value of the Cu_(3)Sb_(0.98)Sn_(0.02)Se_(4)sample was achieved at 1.05 at 623 K when the theoretical yield of a single synthesis was 10 mmol.

关键词： Cu_(3)SbSe_(4) Carrier concentration Phonon scattering Synergistic modulation

Peripheral radial chop technique for phacoemulsification of hard cataracts

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Chinese Medical Journal 2007年第4期120卷 284-286页

作者： li Shao-wei XIE li-xin song zhen-hua MENG li JIANG Jian Shandong Eye Institute Qingdao 266071 China

Background Phacoemulsification yields successful outcomes in eyes with standard cataract. Though techniques have been improved, it is still challenging to perform phacoemulsification in cases of hard cataracts for difficulty in nuclear management and much more complications. This study aimed at describing and evaluating the efficacy and safety of a peripheral radial chop technique to remove hard cataracts. Methods In this prospective study conducted between January 2003 and January 2004, 107 consecutive eyes with hard cataract underwent modified phacoemulsification surgery with peripheral radial chop technique by the Bausch ＆ Lomb Millennium phacoemulsifler with preset parameters of power less than 30%; vaccum, 150 mmHg; and bottle height, 85 cm when a DP8145 phaco tip was used, and vaccum, 380 mmHg; bottle height, 95 cm when a DP8245 phaco tip was used. Results The mean ultrasonic power was 14.7% （range 9% to 19%）, ultrasonic time was 1.98 minutes （range 1.55 to 3.18 minutes）. At 1, 7 and 30 days postoperatively, the eyes with uncorrected visual acuity 0.5 or better accounted for 76.42%, 87.16% and 90.67% respectively. At 1 month, the endothelial cell loss rate was 9.74% （range 8% to 17%）. There were 6 cases of posterior capsule rupture in an early period of study. No serious intraoperaUve or postoperative complications were noted. Conclusions The peripheral radial chop technique was effective without serious complications in hands of an experienced surgeon.

关键词： phacoemulsification chop technique hard cataract