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Green Energy & Environment 2023年第1期8卷 331-337页

作者： Zhanchao Li Yizhuo Wang Qing Li liqing xu Hong Wang Frontier Institute of Science and Technology Xi'an Jiaotong UniversityXi'an710054China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an710054China

Synthesizing ring structure aviation fuels from biomass-derived platform molecules is challenging,especially for bridged ring structure aviation fuels which are typically achieved from fossil-derived chemicals.Herein,we report the synthesis of a series of ring structure biofuels in two steps by a combination of a solvent-free Michael-cyclization reaction and a hydrodeoxygenation(HDO)reaction from lignocellulosederived 5,5-dimethyl-1,3-cyclohexanedione.These biofuels are obtained with high overall yields up to 90%,which exhibit high densities of 0.81 g cm^(-3)-0.88 g cm^(-3)and high volumetric neat heat of combustion(VNHOC)values of 36.0 MJ L^(-1)-38.6 MJ L^(-1).More importantly,bridged-ring structure hydrocarbons can also be achieved in two steps by a combination of a Robinson annulation reaction and an HDO reaction to afford the final products at high overall yields up to 90%.The bridged-ring structure products have comparable high densities and high VNHOC values to the best artificial fuel JP-10(0.94 g cm^(-3)and 39.6 MJ L^(-1)).The results demonstrate a promising way for the synthesis of high-density aviation fuels with different fuel properties at high yields.

关键词： Biofuels 5,5-Dimethyl-1,3-cyclohexanedione Solvent-free Michael-cyclization Robinson annulation Green reaction

Effects of natural forest conversion and plantation tree species composition on soil macrofauna communities in Northeast China mountains

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林业研究:英文版 2023年第5期34卷 1475-1489页

作者： Shuangjiao Ma Qingcheng Wang Yong Zhang Limei Yan Donghai Cui liqing xu Key Laboratory for Sustainable Forest Ecosystem Management−Ministry of Education School of ForestryNortheast Forestry UniversityHarbin 150040People’s Republic of China

As primary and secondary forests are being replaced by plantations across the globe,the soil macrofauna community structure is also affected,but little is known about the impact of mixed culture plantations compared with monocultures on the soil macrofauna.To determine the impact of forest conversion on soil macrofauna,we surveyed the soil macrofauna in two broad-leaved and three coniferous monoculture stands and four coniferous-broadleaved mixed stands,and in adjacent reserved secondary stands as a reference.Soil macro fauna community composition was significant affected by forest type,season and their interaction(P<0.05).The abundance,taxa richness and diversity of soil macro fauna changed to different degrees depending on the plantation type.Broadleaved monoculture stands and secondary stands had similar macrofauna abundance and taxa richness,but values were lower in coniferous stands than in secondary stands.The Shannon index for macrofauna in coniferous stands was also the lowest,but the Pielou index did not differ between forest types.The negative effects of the conifer monoculture on soil macro fauna were not present in the mixed stands with broad-leaved trees.Forest conversion impacted soil properties;soil moisture,NO_(3)^(-),and pH were significant drivers of soil macrofauna community structure.The impact of forest conversion on soil macrofauna was closely dependent on tree species composition and diversity.The macro fauna community structure in the broadleaved and the mixed stands were relatively similar to that in the natural forest,and thus recommended for forest conversion in the study area.

关键词： Forest conversion Plantation forest Tree species composition Soil macrofauna Diversity Functional group

Preferential transport activity of Dk DTX5/MATE5 affects the formation of different astringency in persimmon

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Journal of Integrative Plant Biology 2023年第10期65卷 2304-2319页

作者： Ying Liu Xin Wu Chenfeng Sun Wenxing Chen Meng Zhang Niannian Liu Qinglin Zhang liqing xu Zhengrong Luo National Key Laboratory for Germplasm Innovation&Utilization of Horticultural Crops Huazhong Agricultural UniversityWuhan 430070China

Proanthocyanidins(PAs) are specialized metabolites that infuence persimmon fruit quality.Normal astringent(A)-type and non-astringent(NA)-type mutants show significant variation in PA accumulation, but the infuencing mechanism remains unclear. In this study, among the six identified DTXs/MATEs proteins associated with PA accumulation, we observed that allelic variation and preferential transport by Dk DTX5/MATE5 induced variation in PA accumulation for A-type and NA-type fruit. The expression pattern of Dk DTX5/MATE5 was correlated with PA accumulation in NA-type fruit. Upregulation and downregulation of Dk DTX5/MATE5 promoted and inhibited PA accumulation, respectively, in the NA-type fruit. Interestingly, transporter assays of Xenopus laevis oocytes indicated that Dk DTX5/MATE5 preferentially transported the PA precursors catechin, epicatechin, and epicatechin gallate, resulting in their increased ratios relative to the total PAs, which was the main source of variation in PA accumulation between the A-type and NA-type. The allele lacking Ser-84 in Dk DTX5/MATE5 was identified as a dominantly expressed gene in the A-type and lost its transport function. Site-directed mutagenesis revealed that Dk DTX5/MATE5 binds to PA precursors via Ser-84. These findings clarify the association between the transporter function of Dk DTX5/MATE5 and PA variation, and can contribute to the breeding of new cultivars with improved fruit quality.

关键词： astringency DTX/MATE persimmon(Diospyros kaki Thunb.) proanthocyanidins(PAs) tonoplast transmembrane

Lattice expansion enables interstitial doping to achieve a high average ZT in n-type PbS

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Interdisciplinary Materials 2023年第1期2卷 161-170页

作者： Zhengtao Liu Tao Hong liqing xu Sining Wang Xiang Gao Cheng Chang Xiangdong Ding Yu Xiao Li-Dong Zhao State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong UniversityXi'anChina School of Materials Science and Engineering Beihang UniversityBeijingChina Center for High Pressure Science and Technology Advanced Research(HPSTAR) BeijingChina Institute of Science and Technology Austria KlosterneuburgAustria

Lead sulfide(PbS)presents large potential in thermoelectric application due to its earth-abundant S element.However,its inferior average ZT(ZTave)value makes PbS less competitive with its analogs PbTe and PbSe.To promote its thermoelectric performance,this study implements strategies of continuous Se alloying and Cu interstitial doping to synergistically tune thermal and electrical transport properties in n-type PbS.First,the lattice parameter of 5.93Åin PbS is linearly expanded to 6.03Åin PbS_(0.5)Se_(0.5)with increasing Se alloying content.This expanded lattice in Se-alloyed PbS not only intensifies phonon scattering but also facilitates the formation of Cu interstitials.Based on the PbS_(0.6)Se_(0.4)content with the minimal lattice thermal conductivity,Cu interstitials are introduced to improve the electron density,thus boosting the peak power factor,from 3.88μW cm^(−1)K^(−2)in PbS_(0.6)Se_(0.4)to 20.58μW cm^(−1)K^(−2)in PbS0.6Se0.4−1%Cu.Meanwhile,the lattice thermal conductivity in PbS_(0.6)Se_(0.4)−x%Cu(x=0-2)is further suppressed due to the strong strain field caused by Cu interstitials.Finally,with the lowered thermal conductivity and high electrical transport properties,a peak ZT~1.1 and ZTave~0.82 can be achieved in PbS_(0.6)Se_(0.4)−1%Cu at 300–773K,which outperforms previously reported n-type PbS.

关键词： electrical transport properties interstitial doping PbS thermal conductivity ZT_(ave)

Vulnerable Public Keys in NTRU Cryptosystem

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Chinese Annals of Mathematics,Series B 2020年第5期41卷 657-664页

作者： liqing xu Hao CHEN Chao LI Longjiang QU The College of Information Science and Technology/College of Cyber Security Jinan UniversityGuangzhou 510632China The College of Liberal Arts and Science National University of Defence TechnologyChangsha 410073China

In this paper the authors give an efficient bounded distance decoding(BDD for short)algorithm for NTRU lattices under some conditions about the modulus number q and the public key h.They then use this algorithm to give plain-text recovery attack to NTRUEncrypt and forgery attack on NTRUSign.In particular the authors figure out a weak domain of public keys such that the recent transcript secure version of NTRU signature scheme NTRUMLS with public keys in this domain can be forged.

关键词： Lattice CVP NTRU Lattice

混合双馈入直流输电系统的高频振荡特征及机理研究

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中国电机工程学报 2024年第8期44卷 3059-3071,I0010页

作者：杨硕郭春义杜东冶徐李清张加卿新能源电力系统国家重点实验室(华北电力大学) 北京市昌平区102206

在混合双馈入直流输电系统中,由于电网换相换流器型高压直流输电(line commutated converter based high voltage direct current,LCC-HVDC)的存在,系统在不同的联络线长度下呈现出不同的高频振荡特征。为研究混合双馈入直流输电系统的... 详细信息

在混合双馈入直流输电系统中,由于电网换相换流器型高压直流输电(line commutated converter based high voltage direct current,LCC-HVDC)的存在,系统在不同的联络线长度下呈现出不同的高频振荡特征。为研究混合双馈入直流输电系统的高频振荡特征及机理,首先建立系统的状态空间模型,基于此研究系统的高频振荡特征,结果表明,由于LCC子系统的存在,在不同的联络线长度下混合双馈入直流输电系统呈现出不同的高频振荡特征。然后,建立混合双馈入直流系统的高频阻抗模型,研究LCC子系统、联络线长度、模块化多电平换流器(modular multilevel converter,MMC)控制链路延时、交流线路长度等对系统高频阻抗的影响。结果表明,对于无电气距离的混合双馈入系统,LCC滤波器的存在使其无高频振荡风险;对于有电气距离的混合双馈入系统,当LCC和MMC子系统之间的电气距离较近时,LCC交流滤波器对系统高频振荡的抑制效果随着联络线长度的增大而减弱。最后,提出混合双馈入系统无高频振荡风险的联络线临界长度确定方法,并通过理论分析和电磁暂态仿真进行有效性验证。

关键词：混合双馈入直流输电系统高频振荡交流滤波器联络线长度

Number of Species and Geographical Distribution of Diospyros L.(Ebenaceae) in China

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Horticultural Plant Journal 2019年第2期5卷 59-69页

作者： Donglan Tang Qinglin Zhang liqing xu Dayong Guo Zhengrong Luo Key Laboratory of Horticultural Plant Biology Huazhong Agricultural University Nanjing Agricultural Institute of Jiangsu Hilly Region Hubei Collaborative Innovation Center for the Characteristic Resources Exploitation of Dabie Mountains/Hubei Key Laboratory of Economic Forest Germplasm Improvement and Resources Comprehensive Utilization Huanggang Normal University

Diospyros L. is the largest, most widely distributed, and economically important genus of the family Ebenaceae. However, various researchers disagree on the number of species and geographical distribution of Diospyros in China. For the purpose of providing a scientific basis for the effective protection and rational use of Diospyros, the present study involved a comprehensive review of the literature, electronic databases, and herbaria as well as field investigations. The results showed as the following.(1) While 174 scientific names have been published for various taxa of Diospyros in China, by screening and excluding synonyms, 65 species names were considered acceptable; these account for about 12%of the total species of Diospyros globally.(2) A review of herbarium specimens documented that Diospyros occurs in 28 administrative regions of China, more than the literature records. Species richness decreases from south to north in China while Guangxi, Yunnan, Guangdong, and Hainan have the greatest number of species.(3) Among the 65 relatively reliable Diospyros species, 45 species are endemic to China and 18 species are stenochoric. Some species may have become extinct as a result of environmental degradation and the status of some germplasm remain unresolved. In brief, Chinese Diospyros includes abundant, China-specific, and widely distributed features. Nevertheless, comprehensive species delimitation and the analysis of phylogenetic relationships will still require further study.

关键词： Diospyros L. Ebenaceae species number geographic distribution

基于桥臂调制波调整的多端柔直系统直流过电压抑制策略

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中国电力 2024年第4期57卷 171-181页

作者：彭茂兰冯雷王宇徐李清赵薇郭春义南方电网公司直流输电装备与海底电缆安全运行联合实验室(超高压输电公司电力科研院) 广东广州510663 新能源电力系统全国重点实验室(华北电力大学) 北京102206

基于模块化多电平换流器(modular multilevel converter,MMC)的多端柔性直流输电系统能够实现多电源供电和多落点受电,运行方式灵活,是解决清洁能源并网和消纳问题的有效技术手段。然而当系统受端交流侧发生故障时将出现盈余功率,导致... 详细信息

基于模块化多电平换流器(modular multilevel converter,MMC)的多端柔性直流输电系统能够实现多电源供电和多落点受电,运行方式灵活,是解决清洁能源并网和消纳问题的有效技术手段。然而当系统受端交流侧发生故障时将出现盈余功率,导致直流过电压问题。对此,提出一种基于桥臂调制波动态调整的多端柔直系统直流过电压抑制策略。所提策略通过在换流阀桥臂调制波中引入直流电压偏差控制,动态调整暂态期间桥臂调制波的直流电压参考值,从而减少桥臂投入的子模块数量,最终达到抑制直流过电压的目的。为验证所提控制策略的有效性,在PSCAD/EMTDC中搭建了送端光水打捆经四端柔性直流输电的外送系统,给出了所提控制策略的参数设计方法。通过设置受端交流系统不同工况,对比研究了所提控制策略投入后的系统直流过电压特性,结果表明所提控制策略可以有效抑制因受端交流侧故障引起的多端柔性直流输电系统的直流过电压。

关键词：多端柔性直流输电系统盈余功率直流过电压桥臂调制波动态调整直流电压偏差控制

Study on Characteristics and Reduction Countermeasures of the Agricultural Carbon Emission in China

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Meteorological and Environmental Research 2013年第11期4卷 58-62页

作者： liqing xu Jianjun Bai School of Business Jiangnan University

Based on seven carbon sources including chemical fertilizer, pesticide, agricultural film, nitrogen fertilization, agricultural machinery, irri- gation and straw burning, the carbon emissions in agricultural production of China during 1995-2011 was calculated. The results showed that both total agricultural carbon emission and per capita agricultural carbon emission overall presented growth trends, and the growth rate began to slow in recent years. The agricultural carbon emission intensity decreased year by year. Straw burning was the primary carbon source in China＇s agricul- ture, followed by chemical fertilizer. Total agricultural carbon emission in China in 17 years experienced three stages of ＂fluctuated growth -slow drop-new growth＂. Finally, suggestions and countermeasures of the low-carbon agriculture development in China from three aspects were proposed.

关键词： Agricultural carbon emission General characteristics Carbon emission reduction Countermeasures China

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中国东北东部山区19年生脂松的引种效果

东北林业大学学报 2024年第1期52卷 1-5页

作者：武慧蓉王庆成张勇徐立清于均屹东北林业大学哈尔滨150040

为评价我国东北东部山区脂松(Pinus resinosa)的引种效果,探究脂松在各引种栽培区的生长适应性,以3个不同试验区(帽儿山、露水河、湾甸子)19年生的脂松人工林为研究对象,通过外业调查和树干解析获取生长数据,分析树高、胸径和材积生长... 详细信息

为评价我国东北东部山区脂松(Pinus resinosa)的引种效果,探究脂松在各引种栽培区的生长适应性,以3个不同试验区(帽儿山、露水河、湾甸子)19年生的脂松人工林为研究对象,通过外业调查和树干解析获取生长数据,分析树高、胸径和材积生长过程。结果表明:引种到东北东部山区3个试验区的脂松均能正常生长,而且生长规律基本一致;胸径随着年龄的增大呈S型曲线增长,树高和材积生长整体呈J型曲线增长;5年生脂松树高生长速率为0.17~0.20 m/a,树高从生长第6年开始进入速生期,6~19年生脂松的树高生长速率达0.53~0.66 m/a;脂松胸径起始连年生长量小,之后随着林龄的增加胸径快速增大,林龄达到17 a时,脂松胸径生长开始缓慢下降;林龄1~6 a的脂松材积增长缓慢,且各试验区相差不大,随着林龄的增加迅速增长,露水河脂松材积生长优势逐渐明显。露水河试验区19年生脂松平均树高、胸径和材积表现最好。因此,引种至我国东北东部山区的脂松生长适应性良好,连年生长量大,生长速率快,可以作为优良常绿针叶树种栽培。

关键词：东北东部山区脂松引种树干解析生长规律