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| 1 | A comprehensive review of Energy Internet: basic concept,operation and planning methods, and research prospects显示文摘With the intensifying energy crisis and environmental pollution, the Energy Internet and corresponding patterns of energy use have been attracting more and more attention. In this paper, the basic concept and characteristics of the Energy Internet are summarized, and its basic structural framework is analyzed in detail. On this basis,couplings between the electric power system and other systems such as the cooling and heating system, the natural gas system, and the traffic system are analyzed, and the operation and planning of integrated energy systems in both deterministic and uncertain environments are comprehensively reviewed. Finally, the research prospects and main technical challenges of the Energy Internet are discussed. | Yijia CAO Qiang LI Yi TAN Yong LI Yuanyang CHEN Xia SHAO Yao ZOU | 2018 | Journal of Modern Power Systems and Clean Energy2018,6,3: | 25 |
| 2 | Optimal allocation of multi-type FACTS devices in power systems based on power flow entropy显示文摘Flexible AC transmission systems(FACTS)devices can effectively optimize the distribution of power flow.Power flow entropy can be applied as a measure of load distribution.In this paper,a method is proposed to optimize the distribution of power flow with the coordination of multi-type FACTS devices and establishes the corresponding mathematical models.The modified group searcher optimization(GSO)algorithm is proposed,in which the angle search is combined with chaotic search model to avoid jumping into local optimization.Compared with the different optimal allocation of multi-FACTS devices,the optimal allocation of multi-FACTS devices is achieved under the economic constraints.The locations obtained by this method can achieve the purpose of balancing power flow and enhancing the system performances.The simulations are demonstrated in an IEEE 118-bus power system with two classical types of FACTS,namely static var compensator(SVC)and thyristor controlled series Compensator(TCSC).The simulation results show that the proposed method is feasible and effective. | Canbing LI Liwu XIAO Yijia CAO Qianlong ZHU Baling FANG Yi TAN Long ZENG | 2014 | Journal of Modern Power Systems and Clean Energy2014,2,2: | 23 |
| 3 | Graphene oxide as a water transporter promoting germination of plants in soil显示文摘Graphene 氧化物(去) 是生纳入基础飞机并且到 graphene 格子的边的各种各样的包含氧的功能的组的 graphene 衍生物,因此,众多的恐水病的 sp 2 在聚类的唯一的结构在吸水的 sp 3 公司矩阵以内被孤立。在这研究,吸水的性质和搬运水的性质去被利用支持工厂的萌芽和生长。它被发现那低剂量变显著地在土壤支持了菠菜和细香葱的萌芽。包含氧的功能的组变镇定水,和搬运的恐水病的 sp 2 领域流水到种子加速植物的萌芽。在之间的强壮的相互作用去,稳定的土壤谷物的表面在土壤和阻止的驱散去去。另外,不去在表面上或在工厂的房间内被检测;这发现证实了那去不是 phytotoxic。因此,去可以用作有希望的无毒的添加剂增加工厂收益。 | Yijia He Ruirui Hu Yujia Zhong Xuanliang Zhao Qiao Chen Hongwei Zhu | 2018 | Nano Research2018,11,4: | 20 |
| 4 | Risk factors of haemorrhagic transformation for acute ischaemic stroke in Chinese patients receiving intravenous recombinant tissue plasminogen activator:a systematic review and meta-analysis显示文摘Objective To identify risk factors for haemorrhagic transformation in Chinese patients with acute ischaemic stroke treated with recombinant tissue plasminogen activator.Methods We searched electronic databases including PubMed,EMBASE,CNKI and WanFang Data for studies reporting risk factors of haemorrhagic transformation after intravenous thrombolysis.Pooled OR,weighted mean difference(WMD)and 95%CI were estimated.Meta-analysis was performed by using Stata V.14.0 software.results A total of 14 studies were included.The results indicated that older age(WMD=3.46,95%CI 2.26 to 4.66,I^(2)=47),atrial fibrillation(OR 2.66,95%CI 1.85 to 3.81,I^(2)=28),previous stroke(OR 1.68,95%CI 1.08 to 2.60,I^(2)=14),previous antiplatelet treatment(OR 1.67,95%CI 1.17 to 2.38,I^(2)=0),higher National Institute of Health stroke scale scores(OR 1.10,95%CI 1.05 to 1.15,I^(2)=36),systolic(WMD=4.75,95%CI 2.50 to 7.00,I^(2)=42)or diastolic(WMD=2.67,95%CI 1.08 to 4.26,I^(2)=35)pressure,and serum glucose level(WMD=1.44,95%CI 0.62 to 2.26,I^(2)=66)were associated with increased risk of post-thrombolysis haemorrhagic transformation.Conclusion The current meta-analysis identified eight risk factors for post-thrombolysis haemorrhagic transformation in Chinese patients with acute ischaemic stroke.Given the risk of bias,these results should be explained with caution and do not justify withholding intravenous thrombolysis. | Yijia Guo Yaqiong Yang Muke Zhou Li He | 2018 | Stroke & Vascular Neurology2018,3,4: | 18 |
| 5 | Numerical study of the effects of local atmospheric circulations on a pollution event over Beijing–Tianjin–Hebei, China显示文摘Currently, the Chinese central government is considering plans to build a trilateral economic sphere in the Bohai Bay area, including Beijing, Tianjin and Hebei(BTH), where haze pollution frequently occurs. To achieve sustainable development, it is necessary to understand the physical mechanism of the haze pollution there. Therefore, the pollutant transport mechanisms of a haze event over the BTH region from 23 to 24 September 2011 were studied using the Weather Research and Forecasting model and the FLEXible-PARTicle dispersion model to understand the effects of the local atmospheric circulations and atmospheric boundary layer structure. Results suggested that the penetration by sea-breeze could strengthen the vertical dispersion by lifting up the planetary boundary layer height(PBLH) and carry the local pollutants to the downstream areas; in the early night, two elevated pollution layers(EPLs) may be generated over the mountain areas: the pollutants in the upper EPL at the altitude of 2–2.5 km were favored to disperse by long-range transport, while the lower EPL at the altitude of 1 km may serve as a reservoir, and the pollutants there could be transported downward and contribute to the surface air pollution.The intensity of the sea–land and mountain–valley breeze circulations played an important role in the vertical transport and distribution of pollutants. It was also found that the diurnal evolution of the PBLH is important for the vertical dispersion of the pollutants,which is strongly affected by the local atmospheric circulations and the distribution of urban areas. | Yucong Miao Shuhua Liu Yijia Zheng Shu Wang Bicheng Chen Hui Zheng Jingchuan Zhao | 2015 | Journal of Environmental Sciences2015,27,4: | 14 |
| 6 | Estimating regional coal resource efficiency in China using three-stage DEA and bootstrap DEA models显示文摘Based on three-stage data envelopment analysis(DEA) model estimates of resource utilization efficiency of coal,we selected 29 provinces from China's 2012 input-output data and used the bootstrap DEA model to correct the bias.The results show that the mean overall technical efficiency,pure technical efficiency,and scale efficiency was 0.833,0.998,and 0.711 in 2012,respectively.Moreover,the comprehensive technical efficiency score indicates that the scale is invalid.Area utilization efficiencies for the eastern,central,and western regions were 0.917,0.731,and 0.629,respectively.The results prove that there are significant differences in the distribution of coal resources utilization efficiency across regions. | Cui Yijia Huang Guoliang Yin Ziyong | 2015 | International Journal of Mining Science and Technology2015,25,5: | 10 |
| 7 | Cyber-Physical Electrical Energy Systems:Challenges and Issues显示文摘Cyber-physical electrical energy systems(CPEES)combine computation,communication and control technologies with physical power system,and realize the efficient fusion of power,information and control.This paper summarizes and analyzes related critical scientific problems and technologies,which are needed to be addressed with the development of CPEES.Firstly,since the co-simulation is an effective method to investigate infrastructure interdependencies,the co-simulation platform establishment of CPEES and its evaluation is overviewed.Then,a critical problem of CPEES is the interaction between energy and information flow,especially the influence of failures happening in information communication technology(ICT)on power system.In order to figure it out,the interaction is analyzed and the current analysis methods are summarized.For the solution of power system control and protection in information network environment,this paper outlines different control principles and illustrates the concept of distributed coordination control.Moreover,mass data processing and cluster analysis,architecture of communication network,information transmission technology and security of CPEES are summarized and analyzed.By solving the above problems and technologies,the development of CPEES will be significantly promoted. | Xingyu Shi Yong Li Yijia Cao Yi Tan | 2015 | CSEE Journal of Power and Energy Systems2015,1,2: | 8 |
| 8 | 中国脑梗死患者静脉溶栓后出血转化危险因素的系统评价及Meta分析显示文摘Stroke&Vascular Neurology(SVN)新近上线的文章“Risk factors of haemorrhagic transformation for acute ischemic stroke in Chinese patients receiving intravenous recombinant tissue plasminogen activator:a systematic review and meta-analysis”,由四川大学华西医院神经内科何俐教授团队共同完成。 | YIJIA GUO YAQIONG YANG MUKE ZHOU 何俐 | 2018 | 中国卒中杂志2018,13,11: | 8 |
| 9 | Why super sandstorm 2021 in North China?显示文摘Severe sandstorms reoccurred in the spring of 2021 after an absence for more than 10 years in North China.The dust source area,located in Mongolia,suffered destructive cooling and warming in early and late winter,which loosened the land.A lack of precipitation,excessive snow melt and strong evaporation resulted in dry soil and exiguous spring vegetation.A super-strong Mongolian cyclone developed on the bare and loose ground,and easily blew and transported large amounts of sand particles into North China.Furthermore,top-ranking anomalies(sea ice shift in the Barents and Kara Sea,and sea surface temperatures in the east Pacific and northwest Atlantic) were found to induce the aforementioned tremendous climate anomalies in the dust source area.Analys es,based on large-ensemble Coupled Model Intercomparison Project Phase 6,yield results identical to the reanalysis data.Thus,the climate variabilities at different latitudes and synoptic disturbances jointly facilitated the strongest spring sandstorm over the last decade. | Zhicong Yin Yu Wan Yijia Zhang Huijun Wang | 2022 | National Science Review2022,9,3: | 7 |
| 10 | A comprehensive update:gastrointestinal microflora,gastric cancer and gastric premalignant condition,and intervention by traditional Chinese medicine显示文摘With the recent upsurge of studies in the field of microbiology,we have learned more about the complexity of the gastrointestinal microecosystem.More than 30 genera and 1000 species of gastrointestinal microflora have been found.The structure of the normal microflora is relatively stable,and is in an interdependent and restricted dynamic equilibrium with the body.In recent years,studies have shown that there is a potential relationship between gastrointestinal microflora imbalance and gastric cancer(GC)and precancerous lesions.So,restoring the balance of gastrointestinal microflora is of great significance.Moreover,intervention in gastric premalignant condition(GPC),also known as precancerous lesion of gastric cancer(PLGC),has been the focus of current clinical studies.The holistic view of traditional Chinese medicine(TCM)is consistent with the microecology concept,and oral TCM can play a two-way regulatory role directly with the microflora in the digestive tract,restoring the homeostasis of gastrointestinal microflora to prevent canceration.However,large gaps in knowledge remain to be addressed.This review aims to provide new ideas and a reference for clinical practice. | Yuting LU Huayi LIU Kuo YANG Yijia MAO Lingkai MENG Liu YANG Guangze OUYANG Wenjie LIU | 2022 | Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)2022,23,1: | 6 |
| 11 | Analysis and external validation of a nomogram to predict peritoneal dissemination in gastric cancer显示文摘Objective:Peritoneal dissemination is difficult to diagnose by conventional imaging technologies.We aimed to construct a nomogram to predict peritoneal dissemination in gastric cancer(GC)patients.Methods:We retrospectively analyzed 1,112 GC patients in Sun Yat-sen University Cancer Center between2001 and 2010 as the development set and 474 patients from The Sixth Affiliated Hospital,Sun Yat-sen University between 2010 and 2016 as the validation set.The clinicopathological variables associated with gastric cancer with peritoneal dissemination(GCPD)were analyzed.We used logistic regression analysis to identify independent risk factors for peritoneal dissemination.Then,we constructed a nomogram for the prediction of GCPD and defined its predictive value with a receiver operating characteristic(ROC)curve.External validation was performed to validate the applicability of the nomogram.Results:In total,250 patients were histologically identified as having peritoneal dissemination.Logistic regression analysis demonstrated that age,sex,tumor location,tumor size,signet-ring cell carcinoma(SRCC),T stage,N stage and Borrmann classification IV(Borrmann IV)were independent risk factors for peritoneal dissemination.We constructed a nomogram consisting of these eight factors to predict GCPD and found an optimistic predictive capability,with a C-index of 0.791,an area under the curve(AUC)of 0.791,and a 95%confidence interval(95%CI)of 0.762-0.820.The results found in the external validation set were also promising.Conclusions:We constructed a highly sensitive nomogram that can assist clinicians in the early diagnosis of GCPD and serve as a reference for optimizing clinical management strategies. | Xijie Chen Shi Chen Xinyou Wang Runcong Nie Dongwen Chen Jun Xiang Yijia Lin Yingbo Chen Junsheng Peng | 2020 | Chinese Journal of Cancer Research2020,32,2: | 6 |
| 12 | An antiretroviral regimen containing 6 months of stavudine followed by long-term zidovudine for first-fine HIV therapy is optimal in resource-limited settings: a prospective, multicenter study in China显示文摘 | Li Taisheng Guo Fuping Li Yijia Zhang Chengda Han Yang Lye Wei He Yun Lu Hongzhou Xie Jing Huang Aiqiong Li Yanling Tang Xiaoping Wang Hui Zhang Tong Gao Guiju Lei Junkang Zhang Xiaoying Wu Xinhua Sun Yongtao Bai Jinsong Luo Ling Wang Huanlmg | 2014 | Chinese Medical Journal2014,,1: | 6 |
| 13 | Graphene oxide as an antimicrobial agent can extenCthe vase life of cut flowers显示文摘"PlantNanOmics" is an emerging topic in agricultural research that explores thepotential effect of application of nanomaterials on plant growth. Graphene oxide(GO) has excellent properties due to its basal carbon plane and oxygen-containingfunctional groups. In the present work, the antimicrobial activity of GO wasexploited to extend the vase life and improve the quality of cut roses (cv. Carola).The results revealed that the cut roses cultivated in low doses of GO (0.1 mg/L)had longer vase life, larger diameter, and better water relations. Microbialcontaminations at the basal stem end is the most common reason for stemblockage that causes water stress and early wilting of cut flowers. GO wasfound to act as a germicide, effectively inhibiting the microbial growth atthe cut stem end and improving water uptake and water balance of cut roses.Therefore, GO can serve as a promising preservative to increase the ornamentalvalue of cut flowers. | Yijia He Lichao Qian Xu Liu Ruirui Hu Meirong Huang Yule Liu Guoqiang Chen Dusan Losic Hongwei Zhu | 2018 | Nano Research2018,11,11: | 6 |
| 14 | Aquaporin-4 is a potential drug target for traumatic brain injury via aggravating the severity of brain edema显示文摘Background:Traumatic brain edema(TBE)is caused by a specific water channel mediated by membrane aquaporins.Aquaporin-4(AQP4)plays an especially important role in this process,but the relationship between AQP4 and TBE remains unclear.The purpose of this study was to explore expression of AQP4 in the hippocampus after traumatic brain injury(TBI),as well as the effect of brain edema on skeletal protein and its function in hippocampal neurons.Methods:The adult male Wistar rats we divided into a sham group and a TBI group,the latter of which was further divided into 1,3,6,12,24 and 72 hours(h)and 15 days(d)post injury subgroups.A proper TBI model was established,and brain edema was assessed in each group by water content.We measured the abundance of various proteins,including hypoxia inducible factor-1α(HIF-1α),AQP4,microtubule-associated protein 2(MAP2),tau-5 protein,phosphorylated level of TAU,synaptophysin,cyclic adenosine monophosphate response element binding protein(CREB),phosphorylated CREB and general control nonrepressed 2,in each group.Hippocampal neurons and spatial memory test were analyzed in different time points.Results:Compared with that in the sham group,the level of AQP4 in hippocampal neurons began to significantly increase at 1 h post TBI and then decreased at 15 d post TBI.During this time frame,AQP4 level peaked at 12 and 72 h,and these peaks were closely correlated with high brain water content.HIF-1αdisplayed a similar trend.Conversely,levels of MAP2 began to decrease at 1 h post TBI and then increase at 15 d post TBI.In addition,the most severe brain edema in rats was found at 24 h post TBI,with neuronal loss and hippocampal dendritic spine injury.Compared to those in the sham group,rats in the TBI groups had significantly prolonged latency and significantly shortened exploration time.Conclusions:AQP4 level was closely correlated with severity of brain edema,and abnormal levels thereof aggravated such severity after TBI. | Ao Xiong Renping Xiong Jing Yu Yijia Liu Ke Liu Ge Jin Jianzhong Xu Jun Yan | 2021 | Burns & Trauma2021,9,1: | 5 |
| 15 | Effect of Nanocomposites Coatings on Exterior Performance of Bamboo during Aging显示文摘Bamboo deterioration caused by light becomes a significant problem as application of bamboo extends from indoor to outdoor.The color and roughness of bamboo are two important exterior performances.This study focused on UV resistant nano composites coatings for exterior use and what aimed to find a formulation which could enhance the durability of bamboo.Four kinds of film-forming materials and four kinds of nano particles were used to improve bamboo exterior performance.The color and roughness of nano composites coatings were measured during accelerated weathering.Artificial aging time was 174 h at the temperature of 50 ℃.The experiment showed nanocomposites coatings had significant improvement in UV-shielding and nearly all the samples presented a darkening tendency in ΔL* and increasing tendency in Δa*,ΔE* and ΔRa.The orthogonal experiment obtained the least change in color and Ra which could be achieved with nano composites coating made by melamine resin and TiO2 when a* was considered as an important index.Film-forming material was the only factor which had significant influence on color and roughness when a* was not considered as important index,then melamine resin was the best choice. | LI Neng CHEN Yuhe BAO Yongjie ZOU Yijia CAI Hanjiang | 2012 | Chinese Forestry Science and Technology2012,11,Z1: | 4 |
| 16 | Hypoxia-mimicking 3D bioglass-nanoclay scaffolds promote endogenous bone regeneration显示文摘Large bone defect repair requires biomaterials that promote angiogenesis and osteogenesis.In present work,a nanoclay(Laponite,XLS)-functionalized 3D bioglass(BG)scaffold with hypoxia mimicking property was prepared by foam replication coupled with UV photopolymerization methods.Our data revealed that the incorporation of XLS can significantly promote the mechanical property of the scaffold and the osteogenic differentiation of human adipose mesenchymal stem cells(ADSCs)compared to the properties of the neat BG scaffold.Desferoxamine,a hypoxia mimicking agent,encourages bone regeneration via activating hypoxia-inducible factor-1 alpha(HIF-1α)-mediated angiogenesis.GelMA-DFO immobilization onto BG-XLS scaffold achieved sustained DFO release and inhibited DFO degradation.Furthermore,in vitro data demonstrated increased HIF-1αand vascular endothelial growth factor(VEGF)expressions on human adipose mesenchymal stem cells(ADSCs).Moreover,BG-XLS/GelMA-DFO scaffolds also significantly promoted the osteogenic differentiation of ADSCs.Most importantly,our in vivo data indicated BG-XLS/GelMA-DFO scaffolds strongly increased bone healing in a critical-sized mouse cranial bone defect model.Therefore,we developed a novel BG-XLS/GelMA-DFO scaffold which can not only induce the expression of VEGF,but also promote osteogenic differentiation of ADSCs to promote endogenous bone regeneration. | Xiao Zheng Xiaorong Zhang Yingting Wang Yangxi Liu Yining Pan Yijia Li Man Ji Xueqin Zhao Shengbin Huang Qingqing Yao | 2021 | Bioactive Materials2021,6,10: | 4 |
| 17 | PSO-based Optimization for Constant-current Charging Pattern for Li-ion Battery显示文摘A particle swarm optimization algorithm to search for an optimal five-stage constant-current charge pattern is proposed.The goal is to maximize the objective function for the proposed charge pattern based on the charging capacity,time,and energy efficiency,which all share the same weight.Firstly,an equivalent circuit model is built and battery parameters are identified.Then the optimal five-stage constant-current charge pattern is searched using a particle swarm optimization algorithm.At last,comparative experiments using the constant current-constant voltage(CC-CV)method are performed.Although the charging SOC of the proposed charging pattern was 2.5%lower than that of the CC-CV strategy,the charging time and charging energy efficiency are improved by 15.6%and 0.47%respectively.In particular,the maximum temperature increase of the battery is approximately 0.8℃lower than that of the CC-CV method,which indicates that the proposed charging pattern is more secure. | Yixiao Wang Yong Li Li Jiang Yuduo Huang Yijia Cao | 2019 | Chinese Journal of Electrical Engineering2019,5,2: | 4 |
| 18 | A Multi-Scale Urban Atmospheric Dispersion Model for Emergency Management显示文摘To assist emergency management planning and prevention in case of hazardous chemical release into the atmosphere, especially in densely built-up regions with large populations, a multi-scale urban atmospheric dispersion model was established.Three numerical dispersion experiments, at horizontal resolutions of 10 m, 50 m and 3000 m, were performed to estimate the adverse effects of toxic chemical release in densely built-up areas. The multi-scale atmospheric dispersion model is composed of the Weather Forecasting and Research(WRF) model, the Open Source Field Operation and Manipulation software package, and a Lagrangian dispersion model. Quantification of the adverse health effects of these chemical release events are given by referring to the U.S. Environmental Protection Agency's Acute Exposure Guideline Levels. The wind fields of the urban-scale case, with 3 km horizontal resolution, were simulated by the Beijing Rapid Update Cycle system, which were utilized by the WRF model. The sub-domain-scale cases took advantage of the computational fluid dynamics method to explicitly consider the effects of buildings. It was found that the multi-scale atmospheric dispersion model is capable of simulating the flow pattern and concentration distribution on different scales, ranging from several meters to kilometers, and can therefore be used to improve the planning of prevention and response programs. | MIAO Yucong LIU Shuhua ZHENG Hui ZHENG Yijia CHEN Bicheng WANG Shu | 2014 | Advances in Atmospheric Sciences2014,31,6: | 4 |
| 19 | Opposite effects of miR-155 in the initial and later stages of lipopolysaccharide(LPS)-induced inflammatory response显示文摘Although microRNA-155(miR-155)is considered a pro-inflammatory mediator,cumulative evidence indicates that it also has anti-inflammatory effects in macrophages and dendritic cells.In this study,we identified the dramatic expression changes of more than half of potential miR-155-targeted genes upon lipopolysaccharide(LPS)stimulation;223 genes were down-regulated and 85 genes were up-regulated,including suppressor of cytokine signaling 1(SOCS1)and transforming growth factor-β-activated kinase 1-binding protein 2(TAB2),two well-known genes involved in miR-155-mediated regulation of the Toll-like receptor 4(TLR4)signaling pathway.We also found that miR-155 acted as an anti-inflammatory mediator in the initial stage of LPS-induced inflammatory response mainly through repressing TAB2 protein translation,and as a proinflammatory mediator by down-regulating SOCS1 in the later stage.Meanwhile,overexpression of TAB23'untranslated region(UTR)in macrophages promoted the development of endotoxin tolerance by competing for binding with miR-155,which resulted in an elevated expression level of SOCS1 protein.These findings provide new insights for understanding the regulatory mechanisms in fine-tuning of LPS-induced innate immune response. | Yuhua LIU Xiaopeng WAN Yuan YUAN Jingjing HUANG Yijia JIANG Kaiyue ZHAO Yan WANG Yang LIU Qingqing WANG Hongchuan JIN | 2021 | Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)2021,22,7: | 4 |
| 20 | lonization and dissociation of acetonitrile by intense femtosecond laser pulse显示文摘Photoionization and photodissociation of CH3CN were studied by a linear time of flight mass spectrometer coupled with 800 nm, 50 fs laser pulses at intensities of 6.3×1013-1.2×1014 W/cm2. The laser power dependences for principal ions CH3CN+, CH2CN+, CHCN+ and CCN+ were measured, which are consistent with the numbers of photons required to produce the ions via multiphoton ionization and dissociation. The results show that eight-photon non-resonant multiphoton ionization is the main photoionization mechanism of the parent ion CH3CN+, while the fragment ions were produced through the dissociation of the molecules in the super-excited states. | WU Chengyin, XIONG Yijia, GAO Zhen, KONG Fan’ao, LU Haihe, YANG Xiaodong & XU ZhizhanInstitute of Chemistry, Chinese Academy of Sciences, Beijing 100080, China Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China Correspondence should be addressed to Kong Fan’ao | 2000 | Chinese Science Bulletin2000,45,21: | 3 |