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Dy_(2-x)Y_xTi_2O_7: phonon vibration and magnetization with dilution

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Rare Metals 2015年第2期34卷 81-88页

作者： Hui Liu You-Ming Zou Shi-Le Zhang ran-ran Zhang Chang-jin Zhang Yu-Heng Zhang High Magnetic Field Laboratory Chinese Academy of Sciences and University of Science and Technology of China

In this paper, the dilution effects of non-magnetic Y ions on spin-ice compound Dy_2Ti_2O_7 by infrared and Raman spectra and magnetization measurements were investigated. An anomalous phonon softening with temperature decreasing is found in both the parent and diluted compounds, and Y doping can relax the softening of phonons except that of the IR mode near 233 cm^-1, indicating a strong phonon–phonon coupling in the spin-ice *** magnetization measurements reveal that the nonmagnetic impurities do not severely influence the spin-ice rules in the ground state when the level of dilution is not very high. However, a large amount of dilution enhance the disorder and break the spin-ice state because the collective spin-flip clusters are no longer available.

关键词： Dilution effect Spin ice Pyrochlore Frustration

The breeding of japonica rice in northern China: An 11-year study(2006–2016)

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Journal of Integrative Agriculture 2020年第8期19卷 1941-1946页

作者： CUI Yue ZHU meng-meng XU Zheng-jin CHEN Wen-fu Rice Research Institute of Shenyang Agricultural University Shenyang 110866P.R.China

The world’s population is facing food shortages due to climate change and the competition for arable land between food and energy *** national and international projects to develop"super rice"cultivars were established in recent decades to attain a‘third leap forward’in rice *** order to evaluate the breeding process in northern China,an 11-year tracking survey of japonica rice breeding,which involved a total of 520 rice accessions and 67 test plots,was completed in this *** results showed that the yields of these accessions had increased stably,which was similar to control check varieties(CKs).The breeding strategy reduced the panicle number and increased the grain number per panicle through an increase of spikelet density(number of grains per centimeter on the panicle).This high spikelet density benefits not only the yield but also the blast resistance and amylose *** higher latitudes,the preferred rice accessions had slim grain shape and extended growth *** the middle latitudes among the test plots,the breeders focused on reducing the amylose content to improve the cooking quality of the rice *** and blast resistance were the two highest priorities during the breeding selection *** present study evaluated the breeding process in northern China during the last decade,which may lead to new insights into the future of rice breeding.

关键词： rice japonica breeding decade test northern China

Trends of sea surface temperature and sea surface temperature fronts in the South China Sea during 2003–2017

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Acta Oceanologica Sinica 2019年第4期38卷 106-115页

作者： Yi Yu Hao-ran Zhang Jiangbo jin Yuntao Wang State Key Laboratory of Satellite Ocean Environment Dynamics Second Institute of OceanographyMinistry of Natural Resources College of Oceanography Hohai University International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of Sciences State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences

The trends of the sea surface temperature(SST) and SST fronts in the South China Sea(SCS) are analyzed during2003–2017 using high-resolution satellite data. The linear trend of the basin averaged SST is 0.31°C per decade,with the strongest warming identified in southeastern Vietnam. Although the rate of warming is comparable in summer and winter for the entire basin, the corresponding spatial patterns of the linear trend are substantially different between them. The SST trend to the west of the Luzon Strait is characterized by rapid warming in summer, exceeding approximately 0.6°C per decade, but the trend is insignificant in winter. The strongest warming trend occurs in the southeast of Vietnam in winter, with much less pronounced warming in summer. A positive trend of SST fronts is identified for the coast of China and is associated with increasing wind stress. The increasing trend of SST fronts is also found in the east of Vietnam. Large-scale circulation, such as El Ni?o, can influence the trends of the SST and SST fronts. A significant correlation is found between the SST anomaly and Ni?o3.4 index, and the ENSO signal leads by eight months. The basin averaged SST linear trends increase after the El Ni?o event(2009–2010), which is, at least, due to the rapid warming rate causing by the enhanced northeasterly wind. Peaks of positive anomalous SST and negatively anomalous SST fronts are found to co-occur with the strong El Ni?o events.

关键词： South China Sea sea surface temperature sea surface temperature fronts warming trend wind stress

Paleogene integrative stratigraphy and timescale of China

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Science China Earth Sciences 2019年第1期62卷 287-309页

作者： Yuanqing WANG Qian LI Bin BAI Xun jin Fangyuan MAO jin meng Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences Institute of Vertebrate Paleontology and Paleoanthropology Chinese Academy of Sciences CAS Center for Excellence in Life and Paleoenvironment College of Earth Sciences University of Chinese Academy of Sciences American Museum of Natural History

The Paleogene is the first period after the Mesozoic Mass Extinction. Mammals become the dominant group in the terrestrial ecosystem with a rapid radiation, and Asia has been considered to be the origin place of several mammalian *** Paleogene System consists mostly of terrestrial deposits in Asia, especially in East Asia. A well-established regional chronostratigraphic framework is the foundation for understanding both the Paleogene geologic history and evolutionary history of Asia and their relationships. The Paleogene is subdivided into the Paleocene, Eocene and Oligocene in the International Chronostratigraphic Chart. Based on the land mammal ages, the Chinese terrestrial Paleogene can be subdivided into 11 stages:the Shanghuan, Nongshanian and Bayanulanian stages of the Paleocene, the Lingchan, Arshantan, Irdinmanhan, Sharamurunian,Ulangochuian and Baiyinian stages of the Eocene, and the Ulantatalian and Tabenbulukian stages of the Oligocene. These stages have distinctive paleontological characters, with special significance of fossil mammals, which provide a reliable practical *** bases of the Shanghuan, Lingchan, and Ulantatalian stages are coincident respectively with those of the Paleocene, Eocene and Oligocene. The ages for their bases are determined as 66.0, 56.0 and 33.9 Ma, respectively, following that for the corresponding series in the International Chronostratigraphic Chart. For other stages, estimated ages are provided based on available paleomagnetic results.

关键词： Paleogene Correlation Biostratigraphy Magnetostratigraphy Chronostratigraphy

Genetic variation and population structure of the mushroom Pleurotus ferulae in China inferred from nuclear DNA analysis

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Journal of Integrative Agriculture 2016年第10期15卷 2237-2246页

作者： ZHAO meng-ran HUANG Chen-yang WU Xiang-li CHEN Qiang QU Ji-bin LI Yan-chun GAO Wei ZHANG jin-xia Institute of Agricultural Resources and Regional Planning Chinese Academy of Agricultural Sciences/Key Laboratory of Microbial Resources Ministry of Agriculture Key Laboratory of Plant Diversity and Biogeography of East Asia Institute of Botany Chinese Academy of Sciences

To investigate the genetic diversity of an edible fungus Pleurotus ferulae, a total of 89 wild samples collected from six geographical locations in the Xinjiang Uygur Autonomous Region of China and two geographical locations in Italy, were analyzed using three DNA fragments including the translation elongation factor（EF1α）, the second largest subunit of t he RNA polymerase II（RPB2） and the largest subunit of the RNA polymerase II（RPB1）. The results indicated relatively abundant genetic variability in the wild resources of P. ferulae. The analysis of molecular variance（AMOVA） showed that the vast majority of the genetic variation was found within geographical populations. Both the Chinese populations and the Italian populations of P. ferulae displayed a limited genetic differentiation. The degree of differentiation between the Chinese populations and the Italian populations was obviously higher than that between the populations from the same region, and moreover the genetic differentiation among all the tested populations was correlated to the geographical distance. T he phylogeny analyses confirmed that samples from China and Italy belonged to another genetic group separated from Pleurotus eryngii. They were closely related to each other but were clustered according to their geographical origins, which implied the Chinese populations were highly differentiated from the Italian populations because of distance isolation, and the two populations from different regions might be still in the process of allopatric divergence.

关键词： genetic variation population structure genetic differentiation

Cerium(Ⅳ)ammonium nitrate(CAN)-mediated regioselective synthesis and anticancer activity of 6-substituted 5,8-dimethoxy-1,4-naphthoquinone

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Chinese Chemical Letters 2017年第7期28卷 1553-1558页

作者： Guang Huang Hui-ran Zhao Qing-Qing meng Wen Zhou Qi-jing Zhang jin-Yun Dong Jia-Hua Cui Shao-Shun Li School of Pharmacy Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Institute of Pharmaceutical Industry Shanghai 201203China School of Pharmaceutical Sciences and Chemistry Dali UniversityDali 671000China

6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones（6-DMNQ）,the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H2O in comparatively high *** interesting finding was that apart from the reported electron-withdrawing effects of substituents on position 2 of naphthalene ring,regioselective synthesis of 6-DMNQ was largely dependent on the steric effects in CAN-mediated *** selective cytotoxicities of 6-DMNQ from the in vitro cell-based assays were exhibited between the cancer cells and normal ***,most of sulfur-containing 6-DMNQ derivatives displayed better anticancer activities than the corresponding oxygen-containing ones,which could provide an available strategy for the design of 6-DMNQ derivatives as potential anticancer agents.

关键词： 6-Substituted 5 8-O-dimethyl-1 4- naphthoquinone Cerium(Ⅳ) ammonium nitrate Regioselective oxidation Steric effects Antitumor activity Sulfur-containing

Mechanisms of inclusion-induced pitting of stainless steels:A review

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Journal of Materials Science & Technology 2024年第1期168卷 143-156页

作者： Yangting Sun Xin Tan Rulei Lan Guoyong ran jin Li Yiming Jiang Department of Materials Science State Key Laboratory of Molecular Engineering of PolymersFudan UniversityShanghai 200438China

Pitting is a common type of localized corrosion in passive alloys that can cause rapid failure of material or *** the case of stainless steels,non-metallic inclusions have been identified as the most susceptible sites for pitting,and have therefore garnered significant *** review critically ex-amines the issue of how inclusions induce pitting,with a particular focus on three mechanisms:sponta-neous dissolution of inclusions,active dissolution of Cr-depleted regions,and propagation of microcracks at the inclusion-matrix *** researchers have made significant strides in understanding these mechanisms over the past few decades,many gaps and controversies *** such as the ini-tial driving force of inclusion dissolution and factors affecting Cr-depleted regions require further ***,some old concepts and methods need to be revised to arrive at more credible *** review aims to delve deeply into these important issues and provide inspiration for future research.

关键词： Pitting Inclusion Stainless steel Localized corrosion MnS

Unveiling the size effect of nitrogen-doped carbon-supported copper-based catalysts on nitrate-to-ammonia electroreduction

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Nano Research 2024年第4期17卷 2438-2443页

作者： ran Li Taotao Gao Wenxi Qiu Minghao Xie Zhaoyu jin Panpan Li College of Materials Science and Engineering Sichuan UniversityChengdu 610065China Institute for Advanced Study Chengdu UniversityChengdu 610106China Materials Science and Engineering Program and Walker Department of Mechanical Engineering The University of Texas at AustinAustinTexas 78712USA Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054China

The electrocatalytic nitrate reduction reaction(NitRR)represents a promising approach toward achieving economically and environmentally sustainable ***,it remains a challenge to regulate the size effect of electrocatalysts to optimize the catalytic activity and ammonia ***,the Cu-based catalysts were tailored at the atomic level to exhibit a size gradient ranging from single-atom catalysts(SACs,0.15–0.35 nm)to single-cluster catalysts(SCCs,1.0–2.8 nm)and nanoparticles(NPs,20–30 nm),with the aim of studying the size effect for the NO_(3)^(-)-to-NH_(3) reduction ***,the Cu SCCs exhibit enhanced metal–substrate and metal–metal interactions by taking advantageous features of Cu SACs and Cu ***,Cu SCCs achieve exceptional electrocatalytic performance for the NitRR with a maximum Faradaic efficiency of ca.96%NH_(3)and the largest yield rate of ca.1.99 mg·h^(-1)·cm^(-2) at-0.5 V *** hydrogen electrode(RHE).The theoretical calculation further reveals the size effect and coordination environment on the high catalytic activity and selectivity for the *** work provides a promising various size-controlled design strategy for aerogel-based catalysts effectively applied in various electrocatalytic reactions.

关键词： nitrate electroreduction ammonia electrosynthesis size effect single-cluster catalyst

航天印制电路板汽相回流焊工艺的传热机理与等效建模仿真研究

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北京理工大学学报 2025年第1期45卷 60-66页

作者：苏煜许庆金梓谦孟瑛泽亓婷张朋北京理工大学宇航学院北京航天自动控制研究所

针对航天领域中电子器件与电路板集成使用的汽相回流焊工艺进行数值模拟研究，对揭示汽相回流炉内的流体状态、明确传热机理、优化焊接参数以及揭示焊接电路板的温度分布具有极其重要的意义.提出一种针对汽相回流焊工艺过程仿真的数值... 详细信息

针对航天领域中电子器件与电路板集成使用的汽相回流焊工艺进行数值模拟研究，对揭示汽相回流炉内的流体状态、明确传热机理、优化焊接参数以及揭示焊接电路板的温度分布具有极其重要的意义.提出一种针对汽相回流焊工艺过程仿真的数值模拟方法，建立汽相回流炉的整体模型，分析了回流炉中流体的运动状态以及与电路板之间的传热机理.随后建立单层蒸汽层的等效仿真模型，将温度计算结果作为其边界条件，通过设置压强差控制温升速率，对带有电路板的等效模型进行计算，预测焊接电路板的温度变化.将设计试验与仿真进行对比，结果表明，等效模型对电路板的温度分布模拟是准确的，对优化参数具有重要意义.

关键词：汽相回流焊数值模拟传热机理等效模型温度分布