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    题名 作者 年代 出处 被引量
1Internet-based virtual computing environment(iVCE):Concepts and architecture显示文摘Resources over Internet have such intrinsic characteristics as growth, autonomy and diversity, which have brought many challenges to the efficient sharing and comprehensive utilization of these resources. This paper presents a novel approach for the construction of the Internet-based Virtual Computing Environment (iVCE), whose sig- nificant mechanisms are on-demand aggregation and autonomic collaboration. The iVCE is built on the open infrastructure of the Internet and provides harmonious, transparent and integrated services for end-users and applications. The concept of iVCE is presented and its architectural framework is described by introducing three core concepts, i.e., autonomic element, virtual commonwealth and virtual executor. Then the connotations, functions and related key technologies of each components of the architecture are deeply analyzed with a case study, iVCE for Memory.LU Xicheng WANG Huaimin WANG Ji 2006Science in China(Series F)2006,49,6:33
2Spatio-temporal patterns of satellite-derived grassland vegetation phenology from 1998 to 2012 in Inner Mongolia, China显示文摘Spatio-temporal variations of vegetation phenology, e.g. start of green-up season(SOS) and end of vegetation season(EOS), serve as important indicators of ecosystems. Routinely processed products from remotely sensed imagery, such as the normalized difference vegetation index(NDVI), can be used to map such variations. A remote sensing approach to tracing vegetation phenology was demonstrated here in application to the Inner Mongolia grassland, China. SOS and EOS mapping at regional and vegetation type(meadow steppe, typical steppe, desert steppe and steppe desert) levels using SPOT-VGT NDVI series allows new insights into the grassland ecosystem. The spatial and temporal variability of SOS and EOS during 1998–2012 was highlighted and presented, as were SOS and EOS responses to the monthly climatic fluctuations. Results indicated that SOS and EOS did not exhibit consistent shifts at either regional or vegetation type level; the one exception was the steppe desert, the least productive vegetation cover, which exhibited a progressive earlier SOS and later EOS. Monthly average temperature and precipitation in preseason(February, March and April) imposed most remarkable and negative effects on SOS(except for the non-significant impact of precipitation on that of the meadow steppe), while the climate impact on EOS was found to vary considerably between the vegetation types. Results showed that the spatio-temporal variability of the vegetation phenology of the meadow steppe, typical steppe and desert steppe could be reflected by the monthly thermal and hydrological factors but the progressive earlier SOS and later EOS of the highly degraded steppe desert might be accounted for by non-climate factors only, suggesting that the vegetation growing period in the highly degraded areas of the grassland could be extended possibly by human interventions.SHA Zongyao ZHONG Jialin BAI Yongfei TAN Xicheng Jonathan LI 2016Journal of Arid Land2016,8,3:13
3Recent progress in terahertz science and technology显示文摘The relatively new technique of coherent electromagnetic radiation, in the region of 1012 Hz, has potential to detect the nature of low energy processes in physics, chemistry and biomedicine. In this review article, an overview of recent progress of terahertz (THz) science and technology is presented. The development of the THz generation and detection system, the THz radiation applications which include THz time-domain spectroscopy and T-ray imaging, and the future potential of THz wave research are discussed.XU Jingzhou, ZHANG Cunlin and ZHANG Xicheng(1. Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA 2. Department of Physics, Capital Normal University, Beijing 100037, China) 2002Progress in Natural Science:Materials International2002,12,10:13
4effective treatment of post-intubation subglottic stenosis in children with holmium laser therapy and cryotherapy via flexible bronchoscopy显示文摘Importance:Post-intubation subglottic stenosis(SGS)in children can be life threatening.Definitive treatment varies and lacks a universally accepted approach.Objective:We performed a prospective study to assess the safety and feasibility of holmium laser combined with cryotherapy delivered via flexible bronchoscopy for the treatment of post-intubation SGS in children.Methods:This study involved all patients with post-intubation SGS seen at the Interventional Pulmonology Department of Beijing Children's Hospital between July 2014 and December 2016.Holmium laser treatment and cryotherapy was then performed under flexible bronchoscopy,whose parents refused to accept the alternative standard treatment of tracheotomy and balloon dilation under direct laryngoscopy.results:Sixteen patients with post-intubation SGS were included in this study.Ages ranged from 2 months to 12.25 years old.According to the Cotton-Myer grading system,three cases were Grade II,12 cases were Grade III,and one case was Grade IV.According to the McCaffrey system,eight cases were Stage 1,two cases were Stage 2,and six cases were Stage 3.The average number of procedures was 4.88.Fifteen of the 16 patients achieved clinical cure.One patient achieved clinical improvement.The average treatment course duration was 55.31 days.No severe complications were seen.Post-treatment clinical symptoms,endoscopic findings and quality of life showed marked improvement.Interpretation:Our study supports the conclusion that holmium laser treatment combined with cryotherapy via flexible bronchoscopy appears to be a safe and feasible treatment for post-intubation SGS in children.Anxia Jiao Fang Liu Andrew D.Lerner Xiaochun Rao Yan Guo Chenfang Meng Yuena Pan Gan Li Zheng Li Fang Wang Jing Zhao Yuyan Ma Xicheng Liu Xin Ni Kunling Shen 2019Pediatric Investigation2019,3,1:10
5Spectroscopic evidence for triplet excitation energy transfer among carotenoids in the LH2 complex from photosynthetic bacterium Rhodopseudomonas palustris显示文摘The LH2 complex from Rhodopsudomonas (Rps.) palustris is unique in the heterogeneous carotenoid compositions. The dynamics of triplet excited state Carotenoids (3Car*) has been investigated by means of sub-microsecond time-resolved absorption spectroscopy both at physiological temperature (295 K) and at cryogenic temperature (77 K). Broad and asymmetric Tn←T1 transient absorption was observed at room temperature following the photo-excitation of Car at 532 nm, which suggests the contribution from various carotenoid compositions having different numbers of conjugated C=C double bonds (NC=C). The triplet absorption bands of different carotenoids, which superimposed at room temperature, could be clearly distinguished upon decreasing the temperature down to 77 K. At room temperature the shorter-wavelength side of the main Tn←T1 absorption band decayed rapidly to reach a spectral equilibration with a characteristic time constant of~1 μs, the same spectral dynamics, however, was not observed at 77 K. The aforementioned spectral dynamics can be explained in terms of the triplet-excitation transfer among heterogeneous carotenoid compositions. Global spectral analysis was applied to the time-resolved spectra at room temperature, which revealed two spectral components peaked at 545 and 565 nm, and assignable to the Tn←T1 absorption of Cars with NC=C=11 and NC=C=13, respectively. Surprisingly, the decay time constant of a shorter-con- jugated Car, I.e. 0.72 μs (aerobic) and 1.36 μs (anaerobic), is smaller than that of a longer-con- jugated Car, I.e. 2.12 μs (aerobic) and 3.75 μs (anaerobic), which is contradictory to the general rule of carotenoids and relative polyenes. The results are explained in terms of triplet-excitation transfer among different types of Cars. It is postulated that two Cars with different conjugation lengths coexist in an α,β-subunit in the LH2 complex.FENG Juan, WANG Qian, ZHANG Xujia, HUANG Youguo, Al Xicheng, ZHANG Xingkang & ZHANG JianpingState Key Laboratory for Structural Chemistry of Unstable and Stable Species, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China 2004Science China Chemistry2004,47,1:8
6Assessing the impacts of human activities and climate variations on grassland productivity by partial least squares structural equation modeling(PLS-SEM)显示文摘The cause-effect associations between geographical phenomena are an important focus in ecological research. Recent studies in structural equation modeling(SEM) demonstrated the potential for analyzing such associations. We applied the variance-based partial least squares SEM(PLS-SEM) and geographically-weighted regression(GWR) modeling to assess the human-climate impact on grassland productivity represented by above-ground biomass(AGB). The human and climate factors and their interaction were taken to explain the AGB variance by a PLS-SEM developed for the grassland ecosystem in Inner Mongolia, China. Results indicated that 65.5% of the AGB variance could be explained by the human and climate factors and their interaction. The case study showed that the human and climate factors imposed a significant and negative impact on the AGB and that their interaction alleviated to some extent the threat from the intensified human-climate pressure. The alleviation may be attributable to vegetation adaptation to high human-climate stresses, to human adaptation to climate conditions or/and to recent vegetation restoration programs in the highly degraded areas. Furthermore, the AGB response to the human and climate factors modeled by GWR exhibited significant spatial variations. This study demonstrated that the combination of PLS-SEM and GWR model is feasible to investigate the cause-effect relation in socio-ecological systems.SHA Zongyao XIE Yichun TAN Xicheng BAI Yongfei LI Jonathan LIU Xuefeng 2017Journal of Arid Land2017,9,4:8
7Changes in the Thermal and Hydraulic Regime within the Active Layer in the Qinghai-Tibet Plateau显示文摘The change trends of air temperature,precipitation and evaporation from 1999 to 2008 shows that the climate in the Qinghai-Tibet Plateau permafrost region had become warmer.The analysis of the systematic active-layer data monitoring network along the Qinghai-Tibet Highway indicated that the active-layer thickness had been increasing and the soil temperature was rising.The soil temperature was rising in winter but not at the end of spring or during the entire summer.With thickening and warming of the active layer,the liquid water content of the active layer had an obvious downward migration and liquid water content in the top horizons decreased,but in the deeper horizons it increased.XIE Changwei ZHAO Lin WU Tonghua DONG Xicheng 2012Journal of Mountain Science2012,9,4:7
8Clinicopathologic features and treatment efficacy of Chinese patients with BRAF-mutated metastatic colorectal cancer: a retrospective observational study显示文摘Background: The prognostic role of the V600 E mutation of v-raf murine sarcoma viral oncogene homolog B1(BRAF)in metastatic colorectal cancer(mCRC) is well established, but the therapeutic regimen targeting this disease is lacking. This study aimed to analyze the clinicopathologic features of and treatment efficacy of commonly used regimens on BRAF-mutated mCRCs.Methods: We collected and reviewed the medical records of mCRC patients treated at Peking University Cancer Hospital & Institute(Beijing, China) between July 2011 and July 2016. Kirsten rat sarcoma viral oncogene homolog(KRAS),neuroblastoma RAS viral oncogene homolog(NRAS), and BRAF mutational status was assayed using direct sequencing. The details of clinicopathologic characteristics of patients and their responses to FOLFOXIRI regimen or standard therapy were obtained by reviewing the medical records. The progression-free survival(PFS) and overall survival(OS)were assessed using Kaplan-Meier analysis and compared using the log-rank test.Results: Of 1694 patients studied, 75 had BRAF exon 15 mutations. Of these 75 patients, 71 had V600 E mutation, 1 had D594 G mutation, 2 had K601 E mutation, and 1 had a novel T599_V600 insAGA alteration. No patients had KRAS or NRAS mutations. Of 63 patients with BRAFV600 E-mutated mCRC and sufficient clinical data, 27(42.9%) had right-sided colon tumors, 19(30.2%) had left-sided colon tumors, and 17(26.9%) had rectal tumors; 26(41.3%) had peritoneal metastases, and 50(79.4%) had distant lymph node metastases.The patients with BRAF K601 E-and T599_V600 insAGA-mutated tumors had similar clinicopathologic features to those with BRAFV600 E-mutated tumors. Patients with the BRAFV600 E mutation benefited more from FOLFOXIRI regimen compared with patients who underwent standard therapy(overall response rate 83.3% vs. 14.0%; median PFS 6.4 months vs. 2.8 months, P = 0.220; median OS11.0 months vs. 6.9 months, P = 0.048).Conclusions: BRAFV600 E mutations were commonly identified in right-sided tumors and showed a high incidence of peritoneal and distant lymph nodes metastases.This subtype of mCRC was characterized by short OS and unique patterns of metastasis. Compared with standard treatment regimens, the FOLFOXIRI regimen had acceptable and manageable toxicities and favorable efficacy on patients with BRAF-mutated mCRC.Xicheng Wang Qing Wei Jing Gao Jian Li Jie Li Jifang Gong Yanyan Li Lin Shen 2017Chinese Journal of Cancer2017,36,11:6
9Mapping stripe rust resistance genes by BSR-Seq:YrMM58 and YrHY1 on chromosome 2AS in Chinese wheat lines Mengmai 58 and Huaiyang 1 are Yr17显示文摘Stripe rust(yellow rust), caused by Puccinia striiformis f. sp. tritici(PST),is one of the most devastating fungal diseases in common wheat(Triticum aestivum L.) in China and worldwide. Resistance breeding is the most effective strategy to control diseases in crop plants. Chinese wheat lines Mengmai 58 and Huaiyang 1 are highly resistant to PST race CYR34(V26) at the adult plant stage. To genetically map the underlying resistance genes we developed segregating populations by crossing Mengmai 58 and Huaiyang 1 with the susceptible cultivar Nongda 399. The stripe rust resistances in Mengmai 58 and Huaiyang 1 were both controlled by single dominant genes, provisionally designated YrMM58 and YrHY1, respectively. Bulked segregant RNA-Seq(BSR-Seq) analysis showed that YrMM58 and YrHY1 were located in the same distal ~16 Mb region on chromosome 2 AS.Comparative genomics analysis with the physical map of Aegilops tauschii proved useful for developing additional markers to saturate the genetic linkage map. YrMM58 and YrHY1 were mapped to the distal end of chromosome arm 2 AS, with the closest marker WGGB148 being 7.7 cM and 3.8 cM from the resistance gene, which was considered to be Yr17. These markers can be used in marker-assisted selection.Yong Wang Huaizhi Zhang Jingzhong Xie Bingmin Guo Yongxing Chen Huaiyu Zhang Ping Lu Qiuhong Wu Miaomiao Li Deyun Zhang Guanghao Guo Jian Yang Panpan Zhang Yan Zhang Xicheng Wang Hong Zhao Tingjie Cao Zhiyong Liu 2018The Crop Journal2018,6,1:5
10Adaptive Linearized Alternating Direction Method of Multipliers for Non-Convex Compositely Regularized Optimization Problems显示文摘We consider a wide range of non-convex regularized minimization problems, where the non-convex regularization term is composite with a linear function engaged in sparse learning. Recent theoretical investigations have demonstrated their superiority over their convex counterparts. The computational challenge lies in the fact that the proximal mapping associated with non-convex regularization is not easily obtained due to the imposed linear composition. Fortunately, the problem structure allows one to introduce an auxiliary variable and reformulate it as an optimization problem with linear constraints, which can be solved using the Linearized Alternating Direction Method of Multipliers(LADMM). Despite the success of LADMM in practice, it remains unknown whether LADMM is convergent in solving such non-convex compositely regularized optimizations. In this research, we first present a detailed convergence analysis of the LADMM algorithm for solving a non-convex compositely regularized optimization problem with a large class of non-convex penalties. Furthermore, we propose an Adaptive LADMM(Ada LADMM) algorithm with a line-search criterion. Experimental results on different genres of datasets validate the efficacy of the proposed algorithm.Linbo Qiao Bofeng Zhang Xicheng Lu Jinshu Su 2017Tsinghua Science and Technology2017,22,3:5
11国家电网风电场接入电网技术规定(试行)显示文摘State Grid Companies of China(West Chang’an Street 86,Xicheng District,Beijing 100031,China) 2009山西能源与节能2009,,5:5
12Bevacizumab biosimilar LY01008 compared with bevacizumab(Avastin)as first-line treatment for Chinese patients with unresectable,metastatic,or recurrent non-squamous non-small-cell lung cancer:A multicenter,randomized,double-blinded,phase Ⅲ trial显示文摘Background:Previous studies have demonstrated the preclinical pharmacological and toxicological consistency,and clinical pharmacokinetic equivalence of bevacizumab biosimilar LY01008 with reference bevacizumab(Avastin).This randomized controlled trial aimed to compare the efficacy and safety of LY01008 with Avastin in first-line treatment of Chinese patients with advanced or recurrent non-squamous non-small cell lung cancer(NSCLC).Methods:StageⅢB-ⅣNSCLC patients with evaluable lesions,good physical status,and adequate organ functions from 67 centers across China were randomized in a ratio of 1:1 to receive LY01008 or Avastin 15 mg/kg intravenously in combination with paclitaxel/carboplatin(combined treatment)for 4-6 cycles,followed by maintenance monotherapy with LY01008 until disease progression,intolerable toxicity,or death.The primary endpoint was objective response rate(ORR)in accordance with Response Evaluation Criteria in Solid Tumors(RECIST)version 1.1 confirmed by independent radiological review committees(IRRC).Secondary endpoints included disease control rate(DCR),duration of response(DoR),progression-free survival(PFS),overall survival(OS),and safety.This study was registered in Clinical Trials.gov(NCT03533127).Results:Between December 15^(th),2017,and May 15^(th),2019,a total of 649 patients were randomized to the LY01008(n=324)or Avastin(n=325)group.As of September 25th,2019 for primary endpoint analysis,589 patients received ORR evaluation,with a median number of combined treatment cycles of 5(range 1-6)andmedian duration of treatment of 3.0(range 0.0-5.1)months.ORRof responseevaluable patients in the LY01008 and Avastin groups were 48.5% and 53.0%,respectively.The stratified ORR ratio was 0.91(90%CI 0.80-1.04,within the prespecified equivalence margin of 0.75-1.33).Up to May 15^(th),2020,with a median follow-up of 13.6(range 0.8-28.4)months,no notable differences in DCR,median DoR,median PFS,median OS,and 1-year OS rate were observed between the LY01008 and Avastin groups.There were no clinically meaningful differences in safety and immunogenicity across treatment groups.Conclusions:LY01008 demonstrated similarity to Avastin in terms of efficacy and safety in Chinese patients with advanced or recurrent non-squamous NSCLC.LY01008 combined with paclitaxel/carboplatin is expected to become a new treatment option for unresectable,metastatic,LY01008 and Avastin groups.There were no clinically meaningful differences in safety and immunogenicity across treatment groups.Conclusions:LY01008 demonstrated similarity to Avastin in terms of efficacy and safety in Chinese patients with advanced or recurrent non-squamous NSCLC.LY01008 combined with paclitaxel/carboplatin is expected to become a new treatment option for unresectable,metastatic,or recurrent non-squamous NSCLC patients in the first-line setting.Yuankai Shi Kaijian Lei Yuming Jia Bingqiang Ni Zhiyong He Minghong Bi Xicheng Wang Jianhua Shi Ming Zhou Qian Sun Guolei Wang Dongji Chen Yongqian Shu Lianke Liu Zhongliang Guo Yong Liu Junquan Yang Ke Wang Ke Xiao LinWu Tienan Yi Debin Sun Mafei Kang Tianjiang Ma Yimin Mao Jinsheng Shi Tiegang Tang Yan Wang Puyuan Xing Dongqing Lv Wangjun Liao Zhiguo Luo Bin Wang Xiaohong Wu Xiaoli Zhu Shuhua Han Qisen Guo Rongyu Liu Zhiwei Lu Jianyong Zhang Jian Fang Changlu Hu Yinghua Ji Guolong Liu Hong Lu Dedong Wu Junhong Zhang Shuyang Zhu Zheng Liu Wensheng Qiu Feng Ye Yan Yu Yanqiu Zhao Qinhong Zheng Jun Chen Zhanyu Pan Yiping Zhang Wenjuan Lian Bo Jiang Bo Qiu Guojun Zhang Hua Zhang Yanju Chen Yuan Chen Hongbing Duan Manxiang Li Shengming Liu Lijun Ma Hongming Pan Xia Yuan Xueli Yuan Yulong Zheng Emei Gao Li Zhao Shumin Wang Can Wu 2021Cancer Communications2021,41,9:5
13Self-evident Automated Proving Based on Point Geometry from the Perspective of Wu's Method Identity显示文摘The algebraic methods represented by Wu's method have made signi?cant breakthroughs in the ?eld of geometric theorem proving. Algebraic proofs usually involve large amounts of calculations, thus making it diffcult to understand intuitively. However, if the authors look at Wu's method from the perspective of identity, Wu's method can be understood easily and can be used to generate new geometric propositions. To make geometric reasoning simpler, more expressive, and richer in geometric meaning, the authors establish a geometric algebraic system(point geometry built on nearly 20 basic properties/formulas about operations on points) while maintaining the advantages of the coordinate method, vector method, and particle geometry method and avoiding their disadvantages. Geometric relations in the propositions and conclusions of a geometric problem are expressed as identical equations of vector polynomials according to point geometry. Thereafter, a proof method that maintains the essence of Wu's method is introduced to ?nd the relationships between these equations. A test on more than 400 geometry statements shows that the proposed proof method, which is based on identical equations of vector polynomials, is simple and e?ective. Furthermore, when solving the original problem, this proof method can also help the authors recognize the relationship between the propositions of the problem and help the authors generate new geometric propositions.ZHANG Jingzhong PENG Xicheng CHEN Mao 2019Journal of Systems Science & Complexity2019,32,1:4
14Updates in version 2020 of CSCO guidelines for colorectal cancer from version 2019显示文摘According to the latest data released by the National Cancer Center,colorectal cancer(CRC)had the third highest incidence and the fifth highest mortality of all malignancies,with 388,000 new cases and 187,000 cancer deaths in China(1).The Chinese Society of Clinical Oncology(CSCO)originally published the English version of 2018 guideline concerning CRC and updated them in2019(2,3).According to the latest progress,clinical guidelines have been updated.Here,we present the main updates of the 2020 version compared to 2019 version.Shanshan Weng Ying Yuan Xicheng Wang Gong Chen Yi Wang Weiqi Sheng Xinxiang Li Aiping Zhou Zhen Zhang Guichao Li Sanjun Cai Ruihua Xu Jin Li Suzhan Zhang 2020Chinese Journal of Cancer Research2020,32,3:4
15Bake hardening behavior of TRIP and DP steels显示文摘The bake hardening (BH) behavior of transformation-induced plasticity (TRIP) and dual-phase (DP) steels after different prestrains was studied. The experimental results indicate that TRIP steel exhibits good BH ability while DP steel does not, and pre-strain displays a strong effect on the BH values of both steels. The comparison of microstructures of the two steels showed that the hard second phase in the matrix might be harmful to the BH ability. For deformed specimens, baking resulted in a loss of uniform elongation, but there was no obvious decrease in uniform elongation for unprestrained specimens.Jicheng Zhang Renyu Fu Mei Zhang Rendong Liu Xicheng Wei Lin Li 2008Journal of University of Science and Technology Beijing2008,15,2:4
16Updates in version 2019 of CSCO guidelines for colorectal cancer from version 2018显示文摘According to the latest data from cancer registration center, there are estimated to be 3,929,000 individuals newly diagnosed with cancer and 2,338,000 deaths from this disease in China in 2015 (1). Among them, colorectal cancer (CRC) with 388,000 newly diagnosed cases and 187,000 deaths, stands the third place in incidence and the fifth place in mortality. The Chinese Society of Clinical Oncology (CSCO) has organized an expert committee to write and publish the Guideline for Colorectal Cancer in 2017. And its English version has already been published in March 2019 (2). According to the latest progress, the expert committee updated the guideline to the 2019 version in this April, and the summary of the main updates are as following.Ying Yuan Xicheng Wang Gong Chen Yi Wang Weiqi Sheng Xinxiang Li Aiping Zhou Zhen Zhang Guichao Li Sanjun Cai Ruihua Xu Jin Li Suzhan Zhang 2019Chinese Journal of Cancer Research2019,31,3:4
17SKY:Efficient peer-to-peer networks based on distributed Kautz graphs显示文摘Many proposed P2P networks are based on traditional interconnection topologies. Given a static topology,the maintenance mechanism for node join/departure is critical to designing an efficient P2P network. Kautz graphs have many good properties such as constant degree,low congestion and optimal diameter. Due to the complexity in topology maintenance,however,to date there have been no effective P2P networks that are proposed based on Kautz graphs with base > 2. To address this problem,this paper presents the 'distributed Kautz (D-Kautz) graphs' ,which adapt Kautz graphs to the characteristics of P2P networks. Using the D-Kautz graphs we further propose SKY,the first effective P2P network based on Kautz graphs with arbitrary base. The effectiveness of SKY is demonstrated through analysis and simulations.ZHANG YiMing LU XiCheng LI DongSheng 2009Science in China(Series F)2009,52,4:4
18Temperature modulation of concentration quenching in lanthanide-doped nanoparticles for enhanced upconversion luminescence显示文摘lanthanide 离子的做的集中为操作 upconversion nanoparticles (UCNP ) 的光性质是重要的。然而,在高度做的 UCNP 熄灭的严肃的集中为进一步提高的 upconversion 光(UCL ) 仍然是重要限制。此处,我们在熄灭的集中上检验了温度的效果稀土元素的 UCNP,被俯看的一个问题,和我们证明它为 UCNP 的生物医学或光的应用是重要的。在这个工作,我们由做准备了一系列 UCNP 嗯 3+ 在在一个 NaLuF 4:Yb3+ 矩阵的不同集中的光中心。在房间温度(298 K ) ,不变的光致发光(PL ) 光谱学显示出与增加做集中 Er 3+ 排放熄灭的实质的集中。然而,熄灭效果的集中在更低的温度不再是有效的。进一步从解决时间的 PL 光谱学获得的运动曲线证明熄灭动力学的集中极其在低温实验法的温度区域被改变,即,在 160 K 下面。我们熄灭机制的温度可切换的集中上的工作可以使改善 UCL 性质清楚些,支持他们的实际应用。Luoyuan Li Ningjiu Zhao Limin Fu Jing Zhou Xicheng Ai Jianping Zhang 2018Nano Research2018,11,4:3
19Mechanism of intram olecular charge transfer in DNA helix as probed by the use of the fluorescent 2-aminopurine显示文摘As a structural analogue of adenine, 2-aminopurine (2Ap) is often used as a fluorescent probe to study the intramolecular charge transfer reaction in DNA. We have designed and synthesized a series of model DNA helix with the variation in the distance between the 2Ap probe and the GGG sequence, and have investigated, by means of picosecond time-resolved fluorescence spectroscopy, the effect of the length of the bridge (consisting of a number of inosines, I) separating the electron donor (???GGG???) and the acceptor (2Ap) on the charge transfer dynamics. The fluorescence dynamics of 2Ap exhibited three exponential decay components, the one with a time constant of a few hundred picoseconds is assigned to the intramolecular charge transfer from GGG to 2Ap. Within 2.4 nm of the donor-acceptor separation, the rate of charge transfer decreased exponentially upon increasing the separation, from which the decay factor β is determined to be 1.3 nrrf-1. Beyond 2.4 nm, however, the rate started toincrease, this abnormal behavior of charge transfer is interpreted in terms of the match of elec- tronic energies between the l-bridge and the donor/acceptor couple.ZHANG Huijuan WANG Peng WANG Xuefei FENG Juan XU Sichuan AI Xicheng ZHANG Xingkang ZHANG Jianping 2004Science China Chemistry2004,47,5:3
20Embedded DHT overlays in virtual computing environments显示文摘With the rapid development of computing and networking technologies, people propose to build harmonious, trusted and transparent Internet-based virtual computing environments (iVCE). The overlay-based organization of dynamic Internet resources is an important approach for iVCE to realizing efficient resource sharing. DHT-based overlays are scalable, low-latency and highly available; however, the current DHT overlay (SKY) in iVCE cannot satisfy the 'trust' requirements of Internet applications. To address this problem, in this paper we modify SKY and propose TrustedSKY, an embedded DHT overlay technique in iVCE which supports applications to select trusted nodes to form a 'trusted subgroup' in the base overlay and realize secure and trusted DHT routing.ZHANG YiMing, LU XiCheng & LI DongSheng 1National Laboratory for Parallel and Distributed Processing (PDL), Changsha 410073, China 2School of Computer, National University of Defense Technology, Changsha 410073, China 2010Science China(Information Sciences)2010,53,3:2
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