|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | From octahedral structure motif to sub-nanosecond phase transitions in phase change materials for data storage显示文摘Phase change random access memory(PCRAM) has been successfully applied in the computer storage architecture, as storage class memory, to bridge the performance gap between DRAM and Flashbased solid-state drive due to its good scalability, 3 D-integration ability, fast operation speed and compatible with CMOS technology. Focusing on phase change materials and PCRAM for decades, we have successfully developed 128 Mb embedded PCRAM chips, which can meet the requirements of most embedded systems.3 D Xpoint(3 D PCRAM), invented by Intel and Micron, has been regarded as a new breakthrough in the last 25 years since the application of NAND in 1989, which represents state-of-the-art memory technology.This technology has some remarkable features, such as the confined device structure with 20 nm size, the metal crossbar electrodes to reduce the resistance variations in PCRAM arrays, and the ovonic threshold switching selector that can provide a high drive current and a low leakage current. A good understanding of phase change mechanism is of great help to design new phase change materials with fast operation speed,low power consumption and long-lifetime. In this paper, we firstly review the development of PCRAM and different understandings on phase change mechanisms in recent years, and then propose a new view on the mechanism, which is based on the octahedral structure motifs and vacancies. Octahedral structure motifs are generally found in both amorphous and crystalline phase change materials. They are considered to be the basic units during phase transition, which are severely defective in the amorphous phase. These configurations turn into more ordered ones after minor local rearrangements, the growth of which results in the crystallization of rocksalt(RS) phase with a large amount of vacancies in the cation sites. Further driven by thermodynamic driving force, these vacancies move and layer along certain directions; consequently, the metastable RS structure transforms into the stable hexagonal(HEX) structure. Based on our results, we find that reversible phase transition between amorphous phase and RS phase, without further changing into HEX phase, would greatly decrease the required power consumption. Robust octahedra and plenty of vacancies in both amorphous and RS phase, respectively avoiding large atomic rearrangement and providing necessary space, are crucial to achieve the nanosecond or even sub-nanosecond operation of PCRAM. | Zhitang SONG Sannian SONG Min ZHU Liangcai WU Kun REN Wenxiong SONG Songling FENG | 2018 | Science China(Information Sciences)2018，61，8： | 3 |
| 2 | NDVI changes in China between 1989 and 1999 using change vector analysis based on time series data显示文摘Change vector analysis (CVA) and principal component analysis in NDVI time-trajectories space are powerful tools to analyze land-cover change. The magnitude of the change vector indicates amplitude of the change, while its direction indicates the nature of the change. CVA is applied to two remotely sensed indicators of land surface conditions, NDVI and spatial structure, in order to improve the capability to detect and categorize land-cover change. The magnitude and type of changes are calculated in China from 1989 to 1999. Through the research, the main conclusions are drawn as follows: 1) The changes of NDVI are quite different between eastern China and western China, and the change range in the east is bigger than that in the west. The trend in NDVI time series is smoothly increasing, the increases happen mostly in Taiwan, Fujian, Sichuan and Henan provinces and the decreases occur in Yunnan and Xinjiang. 2) The spatial structure index can indicate changes in the seasonal ecosystem dynamics for spatially heterogeneous landscapes. Most of spatial structure changes, which occurred in southern China, correlated with vegetation growth processes and strike of mountains. | Chen Yun-hao Li Xiao-bing Xie Feng | 2001 | Journal of Geographical Sciences2001，11，4： | 3 |
| 3 | The structure and ability of the China Seismological Gravity Monitoring System显示文摘This paper assesses the structure and ability of Local Seismological Gravity Monitoring Network (LSGMN) in China main tectonic zone and China Seismological Gravity Monitoring System (CSGMS) which formed after the project of 'China Crustal Movement Observation Network (CCMON)' has been performed. The main conclusions drawn are as follows: ①LSGMN has good monitoring and prediction ability for the earthquake of M_s about 5. But it lacks ability to monitor and predict the strong earthquake of M_s>6 because of the little range of the observation network;②CSGMS has good ability to monitor and predict the earthquake of M_s>7, but the resolving power is not enough for the earthquake magnitude from M_s=6 to M_s=7 because the observation stations are too sparse. | 贾民育 詹洁晖 | 2000 | Acta Seismologica Sinica(English Edition)2000，13，4： | 3 |
| 4 | Genetic diversity and temporal changes of an endemic cyprinid fish species, Ancherythroculter nigrocauda,from the upper reaches of Yangtze River显示文摘Small populations with low genetic diversity are prone to extinction. Knowledge on the genetic diversity and structure of small populations and their genetic response to anthropogenic effects are of critical importance for conservation management. In this study, samples of Ancherythroculter nigrocauda, an endemic cyprinid fish from the upper reaches of Yangtze River, were collected from five sites to analyze their genetic diversity and population structure using mitochondrial cytochrome b gene and 14 microsatellite loci. Haplotype diversity, nucleotide diversity, and expected heterozygosity indicated that the A. nigrocauda populations had low genetic diversity, and decreased heavily from 2001 to 2016. Significant genetic differentiation was found among different populations in the cyt b gene and SSR markers based on the genetic differentiation index (F ST), whereas no differentiation was found in 2001. Haplotype genealogy showed that eight out of 15 haplotypes were private to one population. The SSR STRUCTURE analysis showed that there were four genetic clusters in the A. nigrocauda samples, with each population forming a single cluster, except for the Chishui River (CSR) and Mudong River (MDR) populations, which formed a common cluster. Therefore, loss of genetic diversity and increased genetic differentiation were found in the A. nigrocauda populations, which could be attributed to dam construction, overfishing, and water pollution in the upper Yangtze River. It is therefore recommended that the government should ban fishing, control water pollution, increase river connectivity, and establish artificial breeding and stocking. | Dong-Dong Zhai Wen-Jing Li Huan-Zhang Liu Wen-Xuan Cao Xin Gao | 2019 | Zoological Research2019，40，5： | 2 |
| 5 | Spectroscopic study of conformation changes of bovine serum albumin in aqueous environment显示文摘The secondary structural changes of bovine serum albumin (BSA) aqueous solutions with and without calcium cations were investigated by attenuated total reflection-Fourier transform infrared (ATR-FTIR) technology. The spectra of BSA solution and BSA dry powder were mainly reflected the formation of hydrogen bonds between water and BSA. Further investigation indicated that the concentrations of calcium cations in BSA aqueous solution also affected the secondary structural change of the protein. Amide I band was red shifted and amide II band was blue shifted in aqueous environment compared with the dry BSA powder, and the addition of calcium cations further changed the amide bands position, which led to the change of the secondary structure. The result was coinciding with the Raman spectroscopy. | Chune Guo Xiaomi Guo Wubo Chu Nan Jiang He Li | 2019 | Chinese Chemical Letters2019，30，6： | 2 |
| 6 | Study on analysis of crystal structure in CeO_2 doped with Er_2O_3 or Gd_2O_3显示文摘To simulate the effects of burnable poison doping in nuclear fuel UO2,Er2O3(or Gd2O3)-doped CeO2 pellets were prepared. Changes in lattice constant and atomic disordering for CeO2 due to the Er2O3 and Gd2O3 doping were measured by means of XRD and XAFS. By the Er2O3 doping,the lattice constant decreased,and a disordering of lattice structure was induced in the samples. The doping with Er2O3 also induced the disordering of atomic arrangement around Er atoms,which was observed through the change in XAFS spectra. In contrast,the effect of Gd2O3 doping was smaller than that of Er2O3 doping. The result was discussed in terms of ionic size of dopants in CeO2 crystal. | Yuki Tahara Kazufumi Yasunaga Toshiyuki Matsui Fuminobu Hori Akihiro Iwase | 2010 | Journal of Rare Earths2010，28，S1： | 1 |
| 7 | Temperature-dependent structural changes of[Bmim]FeCl4 magnetic ionic liquid characterized by an in-situ X-ray absorption fine structure显示文摘The temperature-dependent structural changes in 1-butyl-3-methylimidazolium tetrafluoride([Bmim]FeCl4)magnetic ionic liquid(MIL)were investigated by using in-situ X-ray absorption fine structure(XAFS)combined with Raman spectroscopy and DFT calculations.XAFS re sults revealed that the coordination number and bond length of Fe-Cl in the anion of[Bmim]FeCl4 MIL decreased with increments in temperature.These results directly reflected the dissociation of tetrahedral structure[FeCl4]^-,and the formation of bridge-chain[Fe2 Cl5]^+,and[FeCl2]^+species in the anion of[Bmim]FeCl4 MIL.These behaviors indicated that[FeCl4]^-dissociation was endothermic,and was promoted by increased temperature.The results obtained through XAFS were in agreement with those obtained through Raman spectroscopy and DFT calculations. | Fangling Jiang Hao Peng Cheng Li Haiying Fu Guozhong Wu | 2020 | Chinese Chemical Letters2020，31，3： | 1 |
| 8 | On the agricultural growth and structural changes in Suzhou Wuxi Changzhou region显示文摘s—Suzhou Wuxi Changzhou Region (Su Xi Chang) is a famous prosperous agricultural region in China. Since the early 1980s agriculture in Su Xi Chang has got constant developed, but its growth rate is lower than the provincial average level of Jiangsu, and its structure has not changed much. Therefore it lost many in the position of agricultural areal division of labour within Jiangsu Province. The authors of this paper suggest that Su Xi Chang agriculture should perform multiple social, economic and ecological functions with the suburban and export oriented farming as the main development direction. It is also necessary to improve management and organization structure for enhancing Su Xi Chang agricultural vitality. | XIE Jie ZENG Zungu Department of Urban and Resources Studies, Nanjing University, Nanjing 210093, CHINA XIONG Ning Department of Geography, Jiangsu Normal College, Nanjing 210013, CHINA | 1998 | Journal of Geographical Sciences1998，8，4： | 0 |
| 9 | Structure and Tone Change of the Press in View of the Reports of the Public Mood in the Era of Change of Regime(October 1988-January 1989)显示文摘1988 and 1989 was the dawn of Hungarian change of regime.The impact of the upcoming change is also well-documented in informers'reports of the public mood.The lecture examines the structure and tone of the press from this particular aspect from October 1988 to January 1989.How the reports of the public mood were reflected on the free press?Membership of a state party is accustomed to the fact that the caring state determines what needs to be done.Fresh media products and their multi-faceted vision caused them serious confusion.For reports of the public mood,it is not to be overlooked that their creators have been working on orders.Some of informers recorded what readers of the reports of the public mood expected.Others wrote what they really heard.Many people were shocked to see more newspapers,magazines,and TV channels.Others demanded their banning immediately.The media activity was considered by many sources as self-directed and provocative.Some reported that many people agreed with the change.But most people wrote that conflicting news is causing serious confusion.The sudden freedom came to surprise most of the people.The following quotation summarizes this:'The majority did not know what was right,what could be done,and what could not be done.The variety of newspapers does not help clarity of vision but the difficulty of orientation'. | Csaba Katona | 2018 | Cultural and Religious Studies2018，6，8： | 0 |
| 10 | Effect of B alloying on magnetocaloric effect of Gd_(5.1)Si_2Ge_2 alloy in low magnetic field | Xue-ling HOU~(1,2),Xiang JIE~1,Jian HUANG~1,Zhi ZENG~1,Hui-min HU~1,Guan-chang ZHANG~1,Hui XU~(1,2) 1.Institute of Materials Science,Shanghai University,Shanghai 200072,China 2.Laboratory for Microstructures,Shanghai University,Shanghai 200072,China | 2011 | Progress in Natural Science:Materials International2011，21，5： | 0 |
| 11 | Structure change of ^(156)Yb at high-spin states显示文摘High-spin states of 156Yb have been studied via the 144Sm(16O,4n)156Yb fusion-evaporation reaction at beam energy 102 MeV. The positive-parity yrast band and negative-parity cascade have been extended up to higher-spin states, respectively. The characteristics of the negative-parity sequence above the 25-state may related to the excitation from the nucleon in the Z =64, N =82 core. The E-GOS curve for the positiveparity yrast sequence in 156Yb indicate that this nucleus may undergo an evolution from quasivibrational to quasirotational structure with increasing angular momentum. The Cranked Woods-Saxon-Strutinsky calculations by means of Total-Routhian-Surface (TRS) methods has been made to understand this structure change. | 华辉 李忠宇 王守宇 孟杰 李智焕 李湘庆 许甫荣 刘红亮 张双全 周善贵 叶沿林 江栋兴 郑涛 竺礼华 吴晓光 李广生 贺创业 马立英 卢飞 范凤英 韩丽英 王赫 肖军 李雪琴 陈东 方晓 楼建玲 刘颖 郝昕 潘波 李立华 | 2009 | Chinese Physics C2009，33，S1： | 0 |
| 12 | Spike-Grain Structure of Winter Wheat and Its Climate Change Tendency in Jiangsu显示文摘To scientifically respond to the impact of climate change on winter wheat production,spike-grain structure data of winter wheat at Jiangsu Phenometeorological Observatory were taken as the sample. Based on agrometeorology,statistics and GIS analytical technique,status quo of spike-grain structure of winter wheat in Jiangsu and its climate change tendency were analyzed systemically. The results showed that climate change rate( CTR) of mature spike number( NS) was between-53. 37 and 256. 51 spikes/( m^2·10 a),and mean of whole province was 21.45 spikes/( m^2·10 a). CTR of number of grains per panicle( GNPS) was between-0. 58 and 12. 52 grains/( spike·10 a),and mean of whole province was 2. 39 grains/( spike·10 a). CTR of thousand-grain weight( TSW) was between-1. 65 and 16. 39 g/( 1 000 grains·10 a),and mean of whole province was 2. 86 g/( 1 000 grains·10 a). For the means of NS,GNPS,and TSW in whole province,they all showed the increasing trend with climate change,and they were just unbalanced among regions. Climate change induced the variation of meteorological conditions during growth period of winter wheat in Jiangsu. The variation of unity yield( UY) caused by this kind of change trend only accounted for-4. 32%-17. 23% of that in normal climate years,and mean of whole province was 6. 4%. That is to say,comprehensive impact of meteorological condition was favorable for improving the yield of winter wheat with climate change. Therefore,coordination level of winter wheat growth and real-time meteorological conditions could be regulated by breeding the varieties with wide climate suitability,regulating sowing date and density according to local production and management level,rational fertilization and applying growth regulator,to mitigate the adverse effects of climate change on winter wheat production,and reach high yield and quality. | Shang Shun Zhang Xuhui Shang Zhaotang | 2019 | Meteorological and Environmental Research2019，10，1： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员