|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | The novel quantitative trait locus GL3.1 controls rice grain size and yield by regulating Cyclin-T1;3显示文摘增加的庄稼收益被要求支持世界范围的快速的人口生长。谷物重量是米饭产量的一个关键部件,但是控制它的内在的分子的机制留下逃犯。这里,我们报导为米饭谷物长度,重量和产量的控制克隆和一个新量的特点地点(QTL ) 的描述。这个地点, GL3.1,编码蛋白质磷酸酶 kelch (PPKL ) 家庭 —Ser/Thr 磷酸酶。GL3.1 是大谷物 WY3 变化的一个成员,它比小谷物 FAZ1 变化与更弱的 dephosphorylation 活动被联系。GL3.1-WY3 在小穗状花小穗影响蛋白质 phosphorylation 加速房间分割,从而导致更长的谷物和更高的收益。进一步的研究直接显示出那 GL3.1 dephosphorylates 它的底层, Cyclin-T1; 3,它很少仅仅在植物被学习了。Cyclin-T1 的 downregulation; 3 在更短的谷物导致了米饭,它在房间周期规定为 Cyclin-T 显示新奇功能。我们的调查结果为通过影响 Cyclin-T1 的 phosphorylation 的新奇调停磷酸酶的进程被驾驶的谷物尺寸和产量的规定建议新机制; 3 在房间周期前进期间,并且这样提供新卓见进位于庄稼种子开发下面的机制。我们引起了包含表明了增加的谷物产量的自然 GL3.1 等位基因的一个新变化,它显示 GL3.1 是为引起产量很高的庄稼的一个强大的工具。 | Peng Qi You-Shun Lin Xian-Jun Song Jin-Bo Shen Wei Huang Jun-Xiang Shan Mei-Zhen Zhu Liwen Jiang Ji-Ping Gao Hong-Xuan Lin | 2012 | Cell Research2012，22，12： | 132 |
| 2 | Structure and function of aggrecan显示文摘Aggrecan is the major proteoglycan in the articular cartilage. This molecule is important in the proper functioning of articular cartilage because it provides a hydrated gel structure (via its interaction with hyaluronan and link protein) that endows the cartilage with load-bearing properties. It is also crucial in chondroskeletal morphogenesis during development. Aggrecan is a multimodular molecule expressed by chondrocytes. Its core protein is composed of three globular domains (G1, G2, and G3) and a large extended region (CS) between G2 and G3 for glycosaminoglycan chain attachment. G1 comprises the amino terminus of the core protein. This domain has the same structural motif as link protein. Functionally, the G1 domain interacts with hyaluronan acid and link protein, forming stable ternary complexes in the extracellular matrix. G2 is homologous to the tandem repeats of G1 and of link protein and is involved in product processing. G3 makes up the carboxyl terminus of the core protein. It enhances glycosaminoglycan modification and product secretion. Aggrecan plays an important role in mediating chondrocyte-chondrocyte and chondrocyte-matrix interactions through its ability to bind hyaluronan. | CHRIS KIANI, LIWEN CHEN, YAO JIONG WU, ALBERT J YEE, BURTON B YANG, Sunnybrook and Women’s College Health Sciences Centre and Department of Laboratory Medicine and Patobiology, 2 Department of Surgeny, Faculty of Medicine, University of Toronto, Canada | 2002 | Cell Research2002，12，1： | 27 |
| 3 | Diagnostic performance of contrast-enhanced ultrasound and enhanced magnetic resonance for breast nodules显示文摘In the current study, we sought to evaluate the diagnostic efficacies of conventional ultrasound(US), contrastenhanced US(CEUS), combined US and CEUS and magnetic resonance imaging(MRI) in detecting focal solid breast lesions. Totally 117 patients with 120 BI-RADS category 4A-5 breast lesions were evaluated by conventional US and CEUS, and MRI, respectively. SonoVue was used as contrast agent in CEUS and injected as an intravenous bolus; nodule scan was performed 4 minutes after bolus injection. A specific sonographic quantification software was used to obtain color-coded maps of perfusion parameters for the investigated lesion, namely the time-intensity curve.The pattern of contrast enhancement and related indexes regarding the time-intensity curve were used to describe the lesions, comparatively with pathological results. Histopathologic examination revealed 46 benign and 74 malignant lesions. Sensitivity, specificity, and accuracy of US in detecting malignant breast lesions were 90.14%, 95.92%, and 92.52%, respectively. Meanwhile, CE-MRI showed sensitivity, specificity, and accuracy of 88.73%, 95.92%, and91.67%, respectively. The area under the ROC curve for combined US and CEUS in discriminating benign from malignant breast lesions was 0.936, while that of MRI was 0.923, with no significant difference between them, as well as among groups. The time-intensity curve of malignant hypervascular fibroadenoma and papillary lesions mostly showed a fast-in/fast-out pattern, with no good correlation between them(kappa <0.20). In conclusion, the combined use of conventional US and CEUS displays good agreement with MRI in differentiating benign from malignant breast lesions. | Cuiying Li Haiyan Gong Lijun Ling Liwen Du Tong Su Shui Wang Jie Wang | 2018 | The Journal of Biomedical Research2018，32，3： | 27 |
| 4 | Features of Sandy Debris Flows of the Yanchang Formation in the Ordos Basin and Its Oil and Gas Exploration Significance显示文摘Sandy debris flow is a new genetic type of sand bodies,which has gained much attention in recent years and its corresponding theory is proved to be a significant improvement and even partial denial to the 'Bouma Sequence' and 'turbidite fan' deep-water sedimentary theories to some point. Oil exploration researchers are highly concerned with sandy debris flows for its key role in controlling oil and gas accumulation processes.In this article,by applying sandy debris flows theory and combining a lot work o... | LI Xiangbo CHEN Qilin LIU Huaqing WAN Yanrong WEI Lihua LIAO Jianbo LONG Liwen | 2011 | Acta Geologica Sinica(English Edition)2011，85，5： | 24 |
| 5 | Efficacy and safety evaluation of icotinib in patients with advanced non-small cell lung cancer显示文摘Objective: To evaluate the efficacy and safety of icotinib hydrochloride in patients with advanced non-small cell lung cancer (NSCLC). Methods: A total of 89 patients with stage ⅢB or IV NSCLC received icotinib at a dose of 125 mg administered 3 times a day. Icotinib treatment was continued until disease progression or development of unacceptable toxicity. Results: A total of 89 patients were assessable. In patients treated with icotinib, the overall response rate (RR) was 36.0% (32/89), and the disease control rate (DCR) was 69.7% (62/89). RR and DCR were significantly improved in patients with adenocarcinoma versus non-adenocarcinoma (P<0.05). The symptom improvement rate was 57.3% (51/89), and the main symptoms improved were cough, pain, chest distress, dyspnea, and Eastern Cooperative Oncology Group performance status. The main toxic effects were rash [30/89 (33.7%)] and diarrhea [15/89 (16.9%)]. The level of toxicity was typically low. Conclusions: The use of icotinib hydrochloride in the treatment of advanced NSCLC is efficacious and safe, and its toxic effects are tolerable. | Aiqin Gu Chunlei Shi Liwen Xiong Tianqing Chu Jun Pei Baohui Han | 2013 | Chinese Journal of Cancer Research2013，25，1： | 22 |
| 6 | Evapotranspiration of an oasis-desert transition zone in the middle stream of Heihe River, Northwest China显示文摘As a main component in water balance, evapotranspiration is of great importance for water saving and irrigation-measure making, especially in arid or semiarid regions. Although studies of evapotranspiration have been conducted for a long time, studies concentrated on oasis-desert transition zone are very limited. On the basis of the meteorological data and other parameters(e.g. leaf area index(LAI)) of an oasis-desert transition zone in the middle stream of Heihe River from 2005 to 2011, this paper calculated both reference(ET0) and actual evapotranspiration(ETc) using FAO56 Penman-Monteith and Penman-Monteith models, respectively. In combination with pan evaporation(Ep) measured by E601 pan evaporator, four aspects were analyzed:(1) ET0 was firstly verified by Ep;(2) Characteristics of ET0 and ETc were compared, while the influencing factors were also analyzed;(3) Since meteorological data are often unavailable for estimating ET0 through FAO56 Penman-Monteith model in this region, pan evaporation coefficient(Kp) is very important when using observed Ep to predict ET0. Under this circumstance, an empirical formula of Kp was put forward for this region;(4) Crop coefficient(Kc), an important index to reflect evapotranspiration, was also analyzed. Results show that mean annual values of ET0 and ETc were 840 and 221 mm, respectively. On the daily bases, ET0 and ETc were 2.3 and 0.6 mm/d, respectively. The annual tendency of ET0 and ETc was very similar, but their amplitude was obviously different. The differences among ET0 and ETc were mainly attributed to the different meteorological variables and leaf area index. The calculated Kc was about 0.25 and showed little variation during the growing season, indicating that available water(e.g. precipitation and irrigation) of about 221 mm/a was required to keep the water balance in this region. The results provide an comprehensive analysis of evapotranspiration for an oasis-desert transition zone in the middle stream of Heihe River, which was seldom reported before. | LiWen ZHAO WenZhi ZHAO | 2014 | Journal of Arid Land2014，6，5： | 16 |
| 7 | Impact of 1.5°C and 2.0°C global warming on aircraft takeoff performance in China显示文摘Associated with global warming, climate extremes such as extreme temperature will significantly increase. Understanding how climate change will impact the airflights is important to the planning of future flight operations. In this study, the impacts of 1.5 and 2 degree's global warming on the aircraft takeoff performance in China are investigated using a unique climate projection data from an international collaboration project named HAPPI. It is found that the mean summer daily maximum temperature, which is a major factor that affects the flight through changing the aircraft's takeoff weight, will increase significantly with magnitude less than 1.5℃ over most parts of China except for the Tibetan Plateau. The half a degree additional global warming will lead to higher extreme temperature in the arid and semi-arid western China, the Tibetan Plateau and the northeastern China, while the change in eastern China is weak. Five airports including Beijing, Shanghai, Kunming, Lasa and Urumqi will see ~1.0°-2.0℃(1.4°-3.0℃) higher daily maximum temperature under 1.5℃(2.0℃) scenario. The half-degree additional warming will lead to a shift toward higher extreme temperature in these five sites. For both1.5° and 2.0℃ scenarios, the number of weight-restriction days will increase significantly at 3 airports including Beijing, Shanghai, and Lasa. Urumqi will witness an increase of weight-restriction days only in 2.0℃ future. | Tianjun Zhou Liwen Ren Haiwen Liu Jingwen Lu | 2018 | Science Bulletin2018，63，11： | 16 |
| 8 | Sinomenine ester derivative inhibits glioblastoma by inducing mitochondria-dependent apoptosis and autophagy by PI3K/AKT/mTOR and AMPK/mTOR pathway显示文摘Glioblastoma multiforme(GBM)in the central nervous system is the most lethal advanced glioma and currently there is no effective treatment for it.Studies of sinomenine,an alkaloid from the Chinese medicinal plant,Sinomenium acutum,showed that it had inhibitory effects on several kinds of cancer.Here,we synthesized a sinomenine derivative,sino-wcj-33(SW33),tested it for antitumor activity on GBM and explored the underlying mechanism.SW33 significantly inhibited proliferation and colony formation of GBM and reduced migration and invasion of U87 and U251 cells.It also arrested the cell cycle at G2/M phase and induced mitochondria-dependent apoptosis.Differential gene enrichment analysis and pathway validation showed that SW33 exerted anti-GBM effects by regulating PI3 K/AKT and AMPK signaling pathways and significantly suppressed tumorigenicity with no obvious adverse effects on the body.SW33 also induced autophagy through the PI3 K/AKT/mTOR and AMPK/mTOR pathways.Thus,SW33 appears to be a promising drug for treating GBM effectively and safely. | Xiangjin Zheng Wan Li Huanli Xu Jinyi Liu Liwen Ren Yihui Yang Sha Li Jinhua Wang Tengfei Ji Guanhua Du | 2021 | Acta Pharmaceutica Sinica B2021，11，11： | 15 |
| 9 | Photochemical pollution in Lanzhou, China - A case study显示文摘The photochemical air pollution in Xigu district of Lanshou city, Gansu Province was studied during a period of 1981-1984. The extremely high NMHC/NOx ratio and ozone level elevation after rain have been noticed. A series of outdoor and indoor reaction chamber simulation experiments conducted in order to understand the specific conditions. The ozone formation under NMHC/NOx condition and the possible reason for high ozone concentration after rain are discussed. | Tang Xiaoyan , Li Jinglong, Dong ZhenXing, Wang Yuying,Wang Wenxing , Qi Liwen, Liu Xiling, Zhang Yutian, Zhang Xuejin,Tian Bingshen, Jin Suwen , Yang Lingqing and Zhang Yixin Department of Technical Physics,Peking University, Beijing, China. Chinese Reaearch Academy of Eavironmental Sciences, Beijing,China. Gansu Provincial Environmental Research Institute, Lanshou, China. Lanshou Petrochemical Engineering Institute, Lanshou, China. | 1989 | Journal of Environmental Sciences1989，1，1： | 15 |
| 10 | Organelle pH in the Arabidopsis Endomembrane System显示文摘细胞内部的分隔空间的 pH 为房间的生存能力是必要的。尽管有它的关联,很少对这些分隔空间的 pH 被知道。到在 vivo 的措施 pH,我们首先由联合修改溶解度的绿色的改进溶解度的特征产生了二个 pH 传感器荧光灯有 pHluorins 和 codon 的察觉到 pH 能力的蛋白质(GFP )(smGFP ) 在 Arabidopsis 为表示优化了。当 pH 与荧光消失在 pH 被降低, PEpHluorin (plant-solubility-modified 黄道 pHluorin ) 逐渐地失去荧光 6.2 并且 PRpHluorin (plant-solubility-modified ratiomatric pHluorin ) ,一个双刺激的传感器,允许精确大小。分隔空间特定的传感器被进一步熔化特定的排序的信号到 PEpHluorin 和 PRpHluorin 产生。我们的结果证明 cytosol 和原子核的 pH 是类似的(pH 7.3 和 7.2 ) 当 peroxisomes, mitochondrial 矩阵,和 plastidial 基质有碱的 pH 时。能分泌的小径的分隔空间揭示渐渐的使发酸,从 pH 跨越 7.1 在 endoplasmic 蜂窝胃(嗯) 到 pH 5.2 在液泡。令人惊讶地,在 trans-Golgi 网络(TGN ) 的 pH 和 multivesicular 身体(MVB ) 是,与 pH 6.3 和 6.2,相当类似。有 concanamycin A (ConcA ) 的 vacuolar 类型 H+-ATPase (V-ATPase ) 的抑制在 TGN 和液泡在 pH 引起了激烈的增加。总的来说, PEpHluorin 和 PRpHluorin 分别地是为在 vivo 的 pH 的可视化和 quantification 的优秀 pH 传感器。 | Jinbo Shen Yonglun Zeng Xiaohong Zhuang Lei Sun Xiaoqiang Yao Peter Pimpl Liwen Jiang | 2013 | Molecular Plant2013，6，5： | 14 |
| 11 | Genetic Analysis and Fine Mapping of Two Genes for Grain Shape and Weight in Rice显示文摘To identify genetic loci controlling grain weight,an elite indica rice variety,Baodali,with large grains was identified and used in this study.Its derived F2,F3 and BC2F2 with another japonica rice variety Zhonghua 11 were used as mapping populations.Linkage analyses demonstrated that two genes controlling grain weight,designated as GW3 and GW6,were mapped to chromosome 3 and chromosome 6,respectively.Fine mapping delimited GW3 to a 122 kb physical distance between two sequence tagged site markers(WGW16 and WGW19) containing 16 open reading frames annotated by The Institute for Genomic Research(http://www.tigr.org).GW6 was further mapped between two simple sequence repeat markers(RM7179 and RM3187).These results are useful for both marker assisted selection of grain weight,and for further cloning of GW genes,which will contribute to the dissection of the molecular mechanism underlying grain weight in rice. | Longbiao Guo Lilian Ma Hua Jiang Dali Zeng Jiang Hu Liwen Wu Zhenyu Gao Guangheng Zhang Qian Qian | 2009 | Journal of Integrative Plant Biology2009，51，1： | 13 |
| 12 | The Genesis Mechanism of the Mantle Fluid Action and Evolution in the Ore-Forming Process: A Case Study of the Laowangzhai Gold Deposit in Yunnan, China显示文摘Based on petrological studies of the wall rocks, mineralizing rocks, ores and veins from the Laowangzhai gold deposit, it is discovered that along with the development of silication, carbonation and sulfidation, a kind of black opaque ultra-microlite material runs through the spaces between grains, fissures and cleavages. Under observations of the electron microprobe, scanning electronic microscopy and energy spectrum, this kind of ultra-microlite material is confirmed to consist of ultra microcrystalline quartz, silicate, sulfides and carbonates, as well as rutile, scheelite and specularite (magnetite), showing characters of liquation by the analyses of SEM and energy spectrum. The coexistence of immiscibility and precipitating co-crystallization strongly suggests that the mineralizing fluid changed from the melt to the hydrothermal fluid. Combined with the element geochemical researches, it is realized that the ultra-microlite aggregate is the direct relics of the mantle fluid behaving like a melt and supercritical fluid, which goes along with the mantle-derived magma and will escape from the magma body at a proper time. During the alteration process, the nature of the mantle fluid changed and it is mixed with the crustal fluid, which are favorable for mineralization in the Loawangzhai gold deposit. | LIU Xianfan LI Chunhui LU Qiuxia DENG Biping SONG Xiangfeng ZHAO Fufeng CHU Yating XIAO Jixiong YI Liwen HUANG Yupeng | 2012 | Acta Geologica Sinica(English Edition)2012，86，3： | 13 |
| 13 | The role of light in regulating seed dormancy and germination^FA显示文摘Seed dormancy is an adaptive trait in plants. Breaking seed dormancy determines the timing of ger-mination and is, thereby essential for ensuring plant sur-vival and agricultural production. Seed dormancy and the subsequent germination are controlled by both internal cues (mainly hormones) and environmental signals. In the past few years, the roles of plant hormones in regulating seed dormancy and germination have been uncovered. However, we are only beginning to understand how light signaling pathways modulate seed dormancy and inter-action with endogenous hormones. In this review, we summarize current views of the molecular mechanisms by which light controls the induction, maintenance and re-lease of seed dormancy, as well as seed germination, by regulating hormone metabolism and signaling pathways. | Liwen Yang Shuangrong Liu Rongcheng Lin | 2020 | Journal of Integrative Plant Biology2020，62，9： | 11 |
| 14 | Liquid propellant analogy technique in dynamic modeling of launch vehicle显示文摘The coupling effects among lateral mode,longitudinal mode and torsional mode of a launch vehicle cannot be taken into account in traditional dynamic analysis using lateral beam model and longitudinal spring-mass model individually.To deal with the problem,propellant analogy methods based on beam model are proposed and coupled mass-matrix of liquid propellant is constructed through additional mass in the present study.Then an integrated model of launch vehicle for free vibration analysis is established,by which research on the interactions between longitudinal and lateral modes,longitudinal and torsional modes of the launch vehicle can be implemented.Numerical examples for tandem tanks validate the present method and its necessity. | PAN ZhongWen 1,2 ,XING YuFeng 1 ,ZHU LiWen 2 ,DONG Kai 2 &SUN Mu 2 1Solid Mechanics Research Center,Beijing University of Aeronautics and Astronautics,Beijing 100191,China 2 Beijing Astronautics Systems Engineering Institute,Beijing 100076,China | 2010 | Science China(Technological Sciences)2010，53，8： | 11 |
| 15 | Dynamic Feedforward Control of a Novel 3-PSP 3-DOF Parallel Manipulator显示文摘Parallel manipulators with less than six degrees of freedom (DOF) have been increasingly used in high-speed hybrid machine tools. The structural features of parallel manipulators are dynamic, a characteristic that is particularly significant when these manipulators are used in high-speed machine tools. However, normal kinematic control method cannot satisfy the requirements of the control system. Many researchers use model-based dynamic control methods, such as the dynamic feedforward control method. However, these methods are rarely used in hybrid machine tools because of the complex dynamic model of the parallel manipulator. In order to study the dynamic control method of parallel manipulators, the dynamic feedforward control method is used in the dynamic control system of a 3-PSP (prismatic-spherical-prismatic) 3-DOF spatial parallel manipulator used as a spindle head in a high-speed hybrid machine tool. Using kinematic analysis as basis and the Newton-Euler method, we derive the dynamic model of the parallel manipulator. Furthermore, a model-based dynamic feedforward control system consisting of both kinematic control and dynamic control subsystems is established. The dynamic control subsystem consists of two modules. One is used to eliminate the influence of the dynamic characteristics of high-speed movement, and the other is used to eliminate the dynamic disturbances in the milling process. Finally, the simulation model of the dynamic feedforward control system of the 3-PSP parallel manipulator is constructed in Matlab/Simulink. The simulations of the control system eliminating the influence of the dynamic characteristics and dynamic disturbances are conducted. A comparative study between the simulations and the normal kinematic control method is also presented.The simulations prove that the dynamic feedforward control method effectively eliminates the influence of the dynamic disturbances and dynamic characteristics of the parallel manipulator on high-speed machine tools, and significantly improves the trajectory accuracy. This is the first attempt to introduce the dynamic feedfordward control method into the 3-PSP spatial parallel manipulator whose dynamic model is complex and provides a study basis for the real-time dynamic control of the high-speed hybrid machine tools. | HAO Qi GUAN Liwen WANG Jinsong WANG Liping | 2011 | Chinese Journal of Mechanical Engineering2011，24，4： | 10 |
| 16 | Redox-sensitive prodrug nanoassemblies based on linoleic acid-modified docetaxel to resist breast cancers显示文摘Prodrug nanoassemblies, which can refrain from large excipients, achieve higher drug loading and control drug release, have been placed as the priority in drug delivery system. Reasoning that glutathione(GSH) and reactive oxygen species(ROS) are highly upgraded in tumor tissues which makes them attractive targets for drug delivery system, we designed and synthetized a novel prodrug which utilized mono thioether bond as a linker to bridge linoleic acid(LA) and docetaxel(DTX). This mono thioether-linked conjugates(DTX-S-LA) could self-assemble into nanoparticles without the aid of much excipients. The mono thioether endowed the nanoparticles redox sensitivity resulting in specific release at the tumor tissue. Our studies demonstrated that the nanoassemblies had uniform particle size, high stability and fast release behavior. DTX-S-LA nanoassemblies outperformed DTX solution in pharmacokinetic profiles for it had longer circulation time and higher area under curve(AUC). Compared with DTX solution, the redox dual-responsive nanoassemblies had comparable cytotoxic activity. Besides, the antitumor efficacy was evaluated in mice bearing 4 T1 xenograft. It turned out this nanoassemblies couldenhance anticancer efficacy by increasing the dose because of higher tolerance. Overall, these results indicated that the redox sensitivity nanoassemblies may have a great potential to cancer therapy. | Meng Li Liwen Zhao Tao Zhang Yue Shu Zhonggui He Yan Ma Dan Liu Yongjun Wang | 2019 | Acta Pharmaceutica Sinica B2019，9，2： | 10 |
| 17 | High temperature tensile properties of directionally solidified Ni-43Ti-4Al-2Nb-2Hf alloy显示文摘By liquid metal cooling(LMC) process,the Ni-43Ti-4Al-2Nb-2Hf(%,atomic fraction) alloy was directionally solidified(DS).The microstructure and tensile properties at room and elevated temperature were investigated.It was found that the DS process significantly improves the room temperature tensile strength,increasing by 70% compared with the as-cast alloy.After appropriate heat treatment(HT),the average tensile strength reaches above 1900 MPa,nearly twice of the as-cast one.At 800 and 900 ℃,the tensile strengths are about 308 and 169 MPa,respectively. | Jiang, Dongwen Zheng, Lijing Zhou, Lei Pan, Liwen Tang, Xiaoxia Zhang, Hu | 2012 | Rare Metals2012，31，4： | 9 |
| 18 | Advances in BeiDou Navigation Satellite System(BDS)and satellite navigation augmentation technologies显示文摘Several noteworthy breakthroughs have been made with the BeiDou Navigation Satellite System(BDS)and other global navigation satellite systems as well as the associated augmentation systems,such as the commissioning of the BDS-3 preliminary system and the successful launch of the first BDS-3 GEO satellite which carries the satellite-based augmentation payload.Presently,BDS can provide basic services globally,and its augmentation system is also being tested.This paper gives an overview of BDS and satellite navigation augmentation technologies.This overview is divided into four parts,which include the system segment technologies,satellite segment technologies,propagation segment technologies,and user segment technologies.In each part,these technologies are described from the perspectives of preliminary information,research progress,and summary.Moreover,the significance and progress of the BeiDou Satellite-based Augmentation System(BDSBAS),low earth orbit augmentation,and the national BeiDou ground-based augmentation system are presented,along with the airborne-based augmentation system.Furthermore,the conclusions and discussions covering popular topics for research,frontiers in research and development,achievements,and suggestions are listed for future research. | Rui Li Shuaiyong Zheng Ershen Wang Jinping Chen Shaojun Feng Dun Wang Liwen Dai | 2020 | Satellite Navigation2020，1，1： | 9 |
| 19 | Spatial and temporal variations of vegetation in Qinghai Province based on satellite data显示文摘这篇论文使用了五年(2001 ¨ C 2006 ) 有 1-km 的 MODIS NDVI 图象的时间系列在中国生产 Qinghai 省的一张陆地盖子地图的空间分辨率。为有植被上的特殊强调的不同陆地盖子类型的一条分类途径, | WANG Liwen WEI Yaxing NIU Zheng | 2008 | Journal of Geographical Sciences2008，18，1： | 9 |
| 20 | Step kinematic calibration of a 3-DOF planar parallel kinematic machine tool显示文摘This paper presents a novel step kinematic calibration method for a 3 degree-of-freedom(DOF) planar parallel kinematic machine tool,based on the minimal linear combinations(MLCs) of error parameters.The method using mapping of linear combinations of parameters in error transfer multi-parameters coupling system changes the modeling,identification and error compensation of geometric parameters in the general kinematic calibration into those of linear combinations of parameters.By using the four theorems of the MLCs,the sets of the MLCs that are respectively related to the relative precision and absolute precision are determined.All simple and feasible measurement methods in practice are given,and identification analysis of the set of the MLCs for each measurement is carried out.According to the identification analysis results,a step calibration including step measurement,step identification and step error compensation is determined by taking into account both measurement costs and observability.The experiment shows that the proposed method has the following merits:(1) the parameter errors that cannot influence precision are completely avoided;(2) it reflects the mapping of linear combinations of parameters more accurately and enhances the precision of identification;and(3) the method is robust,efficient and effective,so that the errors in position and orientation are kept at the same order of the measurement noise.Due to these merits,the present method is attractive for the 3-DOF planar parallel kinematic machine tool and can be also applied to other parallel kinematic machine tools with weakly nonlinear kinematics. | CHANG Peng,WANG JinSong,LI TieMin,LIU XinJun & GUAN LiWen Department of Precision Instruments and Mechanology,Tsinghua University,Beijing 100084,China | 2008 | Science China(Technological Sciences)2008，51，12： | 9 |
您所在的机构暂未开通此部分的功能，请联系管理员