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Structural analysis of tumor-relatedsingle amino acid mutations in human MxA protein 被引量:3
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作者 Jia-Li Hu Yi-Jun Hua +2 位作者 Yang Chen Bing Yu Song Gao 《Chinese Journal of Cancer》 SCIE CAS CSCD 2015年第12期583-593,共11页
Background:Human myxovirus resistant protein A(MxA),encoded by the myxovirus resistance 1(Mx1) gene,is an interferon(IFN)-triggered dynamin-like multi-domain GTPase involved in innate immune responses against viral in... Background:Human myxovirus resistant protein A(MxA),encoded by the myxovirus resistance 1(Mx1) gene,is an interferon(IFN)-triggered dynamin-like multi-domain GTPase involved in innate immune responses against viral infections.Recent studies suggest that MxA is associated with several human cancers and may be a tumor suppressor and a promising biomarker for IFN therapy.Mxl gene mutations in the coding region for MxA have been discovered in many types of cancer,suggesting potential biological associations between mutations in MxA protein and corresponding cancers.In this study,we performed a systematic analysis based on the crystal structures of MxA and elucidated how these mutations specifically affect the structure and therefore the function of MxA protein.Methods:Cancer-associated Mxl mutations were collected and screened from the COSMIC database.Twenty-two unique mutations that cause single amino acid alterations in the MxA protein were chosen for the analysis.Amino acid sequence alignment was performed using Clustal W to check the conservation level of mutation sites in Mx proteins and dynamins.Structural analysis of the mutants was carried out with Coot.Structural models of selected mutants were generated by the SWISS-MODEL server for comparison with the corresponding non-mutated structures.All structural figures were generated using PyMOL.Results:We analyzed the conservation level of the single-point mutation sites and mapped them on different domains of MxA.Through individual structural analysis,we found that some mutations severely affect the stability and function of MxA either by disrupting the intraVinter-molecular interactions supported by the original residues or by incurring unfavorable configuration alterations,whereas other mutations lead to gentle or no interference to the protein stability and function because of positions or polarity features.The potential clinical value of the mutations that lead to drastic influence on MxA protein is also assessed.Conclusions:Among all of the reported tumor-associated single-point mutations,seven of them notably affect the structure and function of MxA and therefore deserve more attention with respect to potential clinical applications.Our research provides an example for systematic analysis and consequence evaluation of single-point mutations on a given cancer-related protein. 展开更多
关键词 HUMAN cancer MXA protein single-point mutation Crystal structure Domain distribution Proteinstability PROTEIN folding RESIDUE interaction Stereochemistry Polarity
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A Hybrid Optimization Approach of Single Point Incremental Sheet Forming of AISI 316L Stainless Steel Using Grey Relation Analysis Coupled with Principal Component Analysiss
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作者 A Visagan P Ganesh 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS CSCD 2024年第1期160-166,共7页
We investigated the parametric optimization on incremental sheet forming of stainless steel using Grey Relational Analysis(GRA) coupled with Principal Component Analysis(PCA). AISI 316L stainless steel sheets were use... We investigated the parametric optimization on incremental sheet forming of stainless steel using Grey Relational Analysis(GRA) coupled with Principal Component Analysis(PCA). AISI 316L stainless steel sheets were used to develop double wall angle pyramid with aid of tungsten carbide tool. GRA coupled with PCA was used to plan the experiment conditions. Control factors such as Tool Diameter(TD), Step Depth(SD), Bottom Wall Angle(BWA), Feed Rate(FR) and Spindle Speed(SS) on Top Wall Angle(TWA) and Top Wall Angle Surface Roughness(TWASR) have been studied. Wall angle increases with increasing tool diameter due to large contact area between tool and workpiece. As the step depth, feed rate and spindle speed increase,TWASR decreases with increasing tool diameter. As the step depth increasing, the hydrostatic stress is raised causing severe cracks in the deformed surface. Hence it was concluded that the proposed hybrid method was suitable for optimizing the factors and response. 展开更多
关键词 single point incremental forming AISI 316L taguchi grey relation analysis principal component analysis surface roughness scanning electron microscopy
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Efficacy comparison of multipoint and single point scanning panretinal laser photocoagulation in non-proliferative diabetic retinopathy treatment
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作者 Yang-Zhou Zhang Hua Gong +2 位作者 Juan Yang Ji-Pu Bu Hui-Ling Yang 《World Journal of Diabetes》 SCIE 2024年第8期1734-1741,共8页
BACKGROUND Non-proliferative diabetic retinopathy(NPDR)poses a significant challenge in diabetes management due to its microvascular changes in the retina.Laser photocoagulation,a conventional therapy,aims to mitigate... BACKGROUND Non-proliferative diabetic retinopathy(NPDR)poses a significant challenge in diabetes management due to its microvascular changes in the retina.Laser photocoagulation,a conventional therapy,aims to mitigate the risk of progressing to proliferative diabetic retinopathy(PDR).AIM To compare the efficacy and safety of multi-spot vs single-spot scanning panretinal laser photocoagulation in NPDR patients.METHODS Forty-nine NPDR patients(86 eyes)treated between September 2020 and July 2022 were included.They were randomly allocated into single-spot(n=23,40 eyes)and multi-spot(n=26,46 eyes)groups.Treatment outcomes,including bestcorrected visual acuity(BCVA),central macular thickness(CMT),and mean threshold sensitivity,were assessed at predetermined intervals over 12 months.Adverse reactions were also recorded.RESULTS Energy levels did not significantly differ between groups(P>0.05),but the multi-spot group exhibited lower energy density(P<0.05).BCVA and CMT improvements were noted in the multi-spot group at one-month posttreatment(P<0.05).Adverse reaction incidence was similar between groups(P>0.05).CONCLUSION While energy intensity and safety were comparable between modalities,multi-spot scanning demonstrated lower energy density and showed superior short-term improvements in BCVA and CMT for NPDR patients,with reduced laser-induced damage. 展开更多
关键词 Panretinal laser photocoagulation Non-proliferative diabetic retinopathy Efficacy comparison Multipoint single point Treatment assessment
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Common Fixed Point Result of Multivalued and Singlevalued Mappings in Partially Ordered Metric Space 被引量:1
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作者 Rajesh Kumar Saini Archana Sharma 《Advances in Pure Mathematics》 2013年第1期142-148,共7页
In recent times the fixed point results in partially ordered metric spaces has greatly developed. In this paper we prove common fixed point results for multivalued and singlevalued mappings in partially ordered metric... In recent times the fixed point results in partially ordered metric spaces has greatly developed. In this paper we prove common fixed point results for multivalued and singlevalued mappings in partially ordered metric space. Our theorems generalized the theorem in [1] and extends the many more recent results in such spaces. 展开更多
关键词 MULTI-VALUED MAPPING single-Valued MAPPING Partial ORDERING Control Function Fixed point Theorem
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Enhancement of surface wettability via micro-and nanostructures by single point diamond turning 被引量:2
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作者 Nicolás Cabezudo Jining Sun +5 位作者 Behnam Andi Fei Ding Ding Wang Wenlong Chang Xichun Luo Ben B.Xu 《Nanotechnology and Precision Engineering》 EI CAS CSCD 2019年第1期8-14,共7页
Studies on surface wettability have received tremendous interest due to their potential applications in research and industrial processes. One of the strategies to tune surface wettability is modifying surface topogra... Studies on surface wettability have received tremendous interest due to their potential applications in research and industrial processes. One of the strategies to tune surface wettability is modifying surface topography at micro-and nanoscales. In this research, periodic micro-and nanostructures were patterned on several polymer surfaces by ultra-precision single point diamond turning to investigate the relationships between surface topographies at the micro-and nanoscales and their surface wettability. This research revealed that single-point diamond turning could be used to enhance the wettability of a variety of polymers, including polyvinyl chloride(PVC), polyethylene 1000(PE1000), polypropylene copolymer(PP) and polytetrafluoroethylene(PFTE), which cannot be processed by conventional semiconductor-based manufacturing processes. Materials exhibiting common wettability properties(θ≈ 90°) changed to exhibit "superhydrophobic" behavior(θ > 150°). Compared with the size of the structures, the aspect ratio of the void space between micro-and nanostructures has a strong impact on surface wettability. 展开更多
关键词 Contact angle WETTABILITY single-point DIAMOND TURNING STRUCTURED surface HYDROPHOBICITY
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A Guide to Cheek Augmentation: Single-Point Deep Injection of Hyaluronic Acid Filler at Midface in Close Proximity to Medial Suborbicularis Oculi Fat (SOOF) Area 被引量:1
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作者 Chung-Pin Liang Haw-Yueh Thong 《Journal of Cosmetics, Dermatological Sciences and Applications》 2016年第1期1-8,共8页
Loss of volume in midface can result in an aged, wasted appearance. Osseous and fat atrophy with aging may further contribute to the loss of soft tissue support and midface ptosis. In the aging of periorbital area and... Loss of volume in midface can result in an aged, wasted appearance. Osseous and fat atrophy with aging may further contribute to the loss of soft tissue support and midface ptosis. In the aging of periorbital area and midface, fat atrophy occurs mostly in the suborbicularis oculi fat (SOOF) area. The authors proposed that injection of hyaluronic acid (HA) filler to support the SOOF area could counteract the aging sign due to fat atrophy, restore volume loss and achieve a more youthful appearance. The authors described the treatment of 10 female patients who received CHAP<sup></sup><sup>&reg</sup>-particle hyaluronic acid (CHAP<sup>&reg</sup>-HA) injections for cheek augmentation, using single-point deep injection technique at midface in close proximity to SOOF area. Such approach provides satisfactory cheek augmentation results without significant complications. The authors discussed a rationale for their choice of dermal filler and provided an injection technique for restoring volume in the midface region with CHAP<sup>&reg</sup>-HA. Such technique is relatively quick to perform, have little down time, and result in a high rate of patient satisfaction. 展开更多
关键词 Midface Lift Cheek Augmentation Fat Compartment Suborbicularis Oculi Fat (SOOF) single-point Deep Injection Hyaluronic Acid (HA) Filler CHAP<sup>&reg</sup>-Hyaluronic Acid (Crosslinked Hyaluronic Acid Platform CHAP<sup>&reg</sup>-HA) Hyadermis<sup>&reg</sup>
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Parasitic Effects on the Performance of DC-DC SEPIC in Photovoltaic Maximum Power Point Tracking Applications
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作者 Nur Mohammad Muhammad Quamruzzaman +1 位作者 Mohammad Rubaiyat Tanvir Hossain Mohammad Rafiqul Alam 《Smart Grid and Renewable Energy》 2013年第1期113-121,共9页
This paper presents an analysis of the effect of parasitic resistances on the performance of DC-DC Single Ended Pri- mary Inductor Converter (SEPIC) in photovoltaic maximum power point tracking (MPPT) applications. Th... This paper presents an analysis of the effect of parasitic resistances on the performance of DC-DC Single Ended Pri- mary Inductor Converter (SEPIC) in photovoltaic maximum power point tracking (MPPT) applications. The energy storage elements incorporated in the SEPIC converter possess parasitic resistances. Although ideal components significantly simplifies model development, but neglecting the parasitic effects in models may sometimes lead to failure in predicting first scale stability and actual performance. Therefore, the effects of parasitics have been taken into consideration for improving the model accuracy, stability, robustness and dynamic performance analysis of the converter. Detail mathematical model of SEPIC converter including inductive parasitic has been developed. The performance of the converter in tracking MPP at different irradiance levels has been analyzed for variation in parasitic resistance. The converter efficiency has been found above 83% for insolation level of 600 W/m2 when the parasitic resistance in the energy storage element has been ignored. However, as the parasitic resistance of both of the inductor has increased to 1 ohm, a fraction of the power managed by the converter has dissipated;as a result the efficiency of the converter has reduced to 78% for the same insolation profile. Although the increasing value of the parasitic has assisted the converter to converge quickly to reach the maximum power point. Furthermore it has also been observed that the peak to peak load current ripple is reduced. The obtained simulation results have validated the competent of the MPPT converter model. 展开更多
关键词 PHOTOVOLTAIC (PV) Renewable Energy Systems DC-DC CONVERTER PARASITIC Resistance Maximum Power point Tracking (MPPT) single Ended Primary INDUCTANCE CONVERTER (SEPIC)
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Single Point Positioning Using GPS, GLONASS and BeiDou Satellites 被引量:4
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作者 Rock Santerre Lin Pan +1 位作者 Changsheng Cai Jianjun Zhu 《Positioning》 2014年第4期107-114,共8页
This paper introduces the Chinese BeiDou satellite system and its comparison with the actual completed American GPS and the Russian GLONASS systems. The actual BeiDou system consists of 14 satellites covering totally ... This paper introduces the Chinese BeiDou satellite system and its comparison with the actual completed American GPS and the Russian GLONASS systems. The actual BeiDou system consists of 14 satellites covering totally the Asia-Pacific area. A Single Point Positioning (SPP) test has been realised in Changsha, Hunan province, China, to show the advantage of using combined pseudorange solutions from these 3 satellite navigation systems especially in obstructed sites. The test shows that, with an elevation mask angle of 10&#176;, the accuracy is improved by about 20% in horizontal coordinates and nearly 50% in the vertical component using the simultaneous observations of the 3 systems compared to the GPS/GLONASS solution. For the processing with an elevation mask angle of 30°, most of the time less than 4 GPS satellites were available for the GPS-only case and no solution was possible. However, in this difficult situation, the combined GPS/GLONASS/ BeiDou solutions provided an accuracy (rms values) of about 5 m. 展开更多
关键词 BEIDOU GPS GLONASS single point POSITIONING
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A Pulse Width Modulation Scheme With Zero-sequence Voltage Injection for Single Phase Three-level NPC Rectifiers 被引量:9
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作者 宋文胜 冯晓云 《中国电机工程学报》 EI CSCD 北大核心 2011年第36期I0003-I0003,共1页
直流侧中点电位电压偏移是多电平中性点钳位型变流器的主要缺点。以单相三电平NPC整流器为研究对象,以实现直流侧中点电位无漂移为控制目标,以传统的单相三电平单极性载波脉宽调制方法为基础,首先提出一种基于零序电压分量注入的载... 直流侧中点电位电压偏移是多电平中性点钳位型变流器的主要缺点。以单相三电平NPC整流器为研究对象,以实现直流侧中点电位无漂移为控制目标,以传统的单相三电平单极性载波脉宽调制方法为基础,首先提出一种基于零序电压分量注入的载波脉宽调制算法;然后在此基础上给出基于零序电压分量极限值注入的载波脉宽调制算法;并给出这2种方法的零序电压分量的设计方案;最后,对这2种方法进行了详细的理论分析、计算机仿真和1kW样机实验对比验证。研究结果表明:所提出的2种算法都能有效实现直流侧中点电位平衡控制,其中基于零序电压分量极限值注入的载波调制算法的中点电位控制具有更快动态响应速度,且其网侧电流的高次谐波主要分布在开关频率附近;而基于零序电压分量注入的载波调制算法的网侧电流高次谐波主要分布在2倍开关频率附近。但是在一个调制信号周期内,基于零序电压分量极限值注入的载波调制算法的开关切换次数比基于零序电压分量注入的载波调制算法低25%左右。 展开更多
关键词 线
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Cerebral functional imaging of Waiguan (SJ 5) acupoint specificity using single-photon emission computed tomography 被引量:2
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作者 Yong Huang Yangjia Lu +5 位作者 Ganlong Li Xinsheng Lai Hong Zhang Chunzhi Tang JunjunYang Gustav Wik 《Neural Regeneration Research》 SCIE CAS CSCD 2011年第6期428-434,共7页
The action of needling in acupoint therapy has to first be regulated and integrated by the brain, and then it affects the target organ and manifests its therapeutic effects, which is dependent on the specificity of th... The action of needling in acupoint therapy has to first be regulated and integrated by the brain, and then it affects the target organ and manifests its therapeutic effects, which is dependent on the specificity of the acupoints. The authors put forward the hypothesis of the "acupoint-related brain". Single-photon emission computed tomography was used to explore the activation of brain regions following true needling in true acupoint Waiguan (SJ 5), sham needling in true acupoint Waiguan, true needling in a sham point, and sham needling in a sham point. The relative specificity of Waiguan in normal persons was analyzed by observing changes in regional cerebral blood flow. Compared with the sham needling in true acupoint group and sham needling in the sham point group, acupuncture at Waiguan can activate brain regions controlling movement. Compared with true needling in the sham point group, acupuncture at Waiguan can also activate brain regions controlling movement. The results suggest that the specificity of needling at an acupoint is related to certain activated cerebral functional regions, which are associated with the clinical application of the acupoint. 展开更多
关键词 acupoint specificity Waiguan SJ 5 NEEDLING sham needling sham point single-photon emission computed tomography
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Single Point Positioning with Sequential Least-Squares Filter and Estimated Real-Time Stochastic Model 被引量:7
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作者 WU Yun GUO Jiming 《Geo-Spatial Information Science》 2008年第1期13-16,共4页
To obtain higher accurate position estimates, the stochastic model is estimated by using residual of observations, hence, the stochastic model describes the noise and bias in measurements more realistically. By using ... To obtain higher accurate position estimates, the stochastic model is estimated by using residual of observations, hence, the stochastic model describes the noise and bias in measurements more realistically. By using GPS data and broadcast ephemeris, the numerical results indicating the accurate position estimates at sub-meter level are obtainable. 展开更多
关键词 GPS single point positioning functional model stochastic model sequential least-square filter
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Nonlinear Coupled Analysis of a Single Point Mooring System 被引量:2
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作者 WANG Junrong LI Huajun LI Ping ZHOU Kai 《Journal of Ocean University of China》 SCIE CAS 2007年第3期310-314,共5页
Coupled effects on a single point mooring(SPM) system subjected to the combined action of wind,waves and current are studied in this paper. Due to the complicatedness of the sea state and the huge size of the vessel,p... Coupled effects on a single point mooring(SPM) system subjected to the combined action of wind,waves and current are studied in this paper. Due to the complicatedness of the sea state and the huge size of the vessel,physical experimental study is both time consuming and uneconomical,whereas the numerical study is cost-effective and DNV software provides powerful SESAM software in solving the issues. This paper focuses on the modeling process of the SPM system,catenary equilibrium calculation,static analysis of the vessel in three different scenarios,and dynamic response simulation of the SPM system under environmental excitations. The three scenarios in study are as follows:the SPM is under the combined function of(a) wind,waves and current,(b) wind and waves,(c) current and waves. They are so set that one can compare the contributions of different types of loads in both static and dynamic studies. Numerical study shows that wind and current are the two major factors contributing to the mooring line tension,and surge and sway are the two dominant motions of the moored vessel subjected to environmental excitations. 展开更多
关键词 single point mooring system response amplitude operator catenary equilibrium static analysis dynamic response
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Zero-sequence Current Suppressing Strategy for Dual Three-phase Permanent Magnet Synchronous Machines Connected with Single Neutral Point 被引量:3
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作者 Zongwang Li Yuxuan Du +2 位作者 Jinghua Ji Tao Tao Wenxiang Zhao 《CES Transactions on Electrical Machines and Systems》 CSCD 2022年第4期465-472,共8页
Dual three-phase permanent-magnet synchronous machines(DTP-PMSM)connected with a single neutral point provide a loop for zero-sequence current(ZSC).This paper proposes a novel space vector pulse width modulation(SVPWM... Dual three-phase permanent-magnet synchronous machines(DTP-PMSM)connected with a single neutral point provide a loop for zero-sequence current(ZSC).This paper proposes a novel space vector pulse width modulation(SVPWM)strategy to suppress the ZSC.Five vectors are selected as basic voltage vectors in one switching period.The fundamental and harmonic planes and the zero-sequence plane are taken into consideration to synthesis the reference voltage vector.To suppress the ZSC,a non-zero zero-sequence voltage(ZSV)is generated to compensate the third harmonic back-EMF.Rather than triangular carrier modulation,the sawtooth carrier modulation strategy is used to generate asymmetric PWM signals.The modulation range is investigated to explore the variation of modulation range caused by considering the zero-sequence plane.With the proposed method,the ZSC can be considerably reduced.The simulated and experimental results are presented to validate the effectiveness of the proposed modulation strategy. 展开更多
关键词 Zero-sequence current a single neutral point dual three-phase permanent-magnet synchronous machine third harmonic back-EMF
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FIELD STUDIES OF SINGLE POINT IMPACT ON LIQUEFIABLE SOIL FOUNDATION OF HIGHWAY
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作者 沈正 刘志彬 +1 位作者 方磊 李汉光 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2013年第4期404-412,共9页
A highway in the floodplain of the Abandoned Yellow River in the north of Jiangsu Province is recently remediated to reduce liquefaction potential using the dynamic compaction(DC)method of densification of in-place so... A highway in the floodplain of the Abandoned Yellow River in the north of Jiangsu Province is recently remediated to reduce liquefaction potential using the dynamic compaction(DC)method of densification of in-place soils.Firstly,the liquefaction potential of the soil at the project site is analysed according to the code of seismic design.Then the in-situ single point impact tests are performed on the liquefiable soil.Settlement of crater,excess pore pressure,ground heave and lateral deformation under DC impact are measured and analyzed.Subsequently, the standard penetration test(SPT)and cone penetration test(CPT)are used for investigating the compaction effectiveness.At last,the improvement effect of DC is discussed according to the technical specification of dynamic consolidation to ground treatment.The investigation results indicate that the DC technique is an effective way for remediating liquefiable soil in highway engineering practice. 展开更多
关键词 dynamic compaction single point impact LIQUEFACTION standard penetration test SPT improvementdepth
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On ionosphere-delay processing methods for single-frequency precise-point positioning 被引量:1
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作者 Tu Rui Zhang Qin Huang Guanwen Zhao Hong 《Geodesy and Geodynamics》 2011年第1期71-76,共6页
In single-frequency precise-point positioning of a satellite,ionosphere delay is one of the most important factors impacting the accuracy. Because of the instability of the ionosphere and uncertainty of its physical p... In single-frequency precise-point positioning of a satellite,ionosphere delay is one of the most important factors impacting the accuracy. Because of the instability of the ionosphere and uncertainty of its physical properties, the positioning accuracy is seriously limited when using a precision-limited model for correction. In order to reduce the error, we propose to introduce some ionosphere parameter for real-time ionosphere-delay estimation by applying various mapping functions. Through calculation with data from the IGS( International GPS Service) tracking station and comparison among results of using several different models and mapping functions, the feasibility and effectiveness of the new method are verified. 展开更多
关键词 single-frequency precise-point positioning ionosphere delay model correction mapping function parameter estimation
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Numerical Simulation of Azimuthal Uniformity of Injection Currents in Single-Point-Feed Induction Voltage Adders 被引量:1
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作者 魏浩 孙凤举 +4 位作者 尹佳辉 呼义翔 梁天学 丛培天 邱爱慈 《Plasma Science and Technology》 SCIE EI CAS CSCD 2015年第3期235-240,共6页
In order to investigate the injection current uniformity around the induction cell bores, two fully electromagnetic (EM) models are respectively established for a single-stage induction cell and an induction voltage... In order to investigate the injection current uniformity around the induction cell bores, two fully electromagnetic (EM) models are respectively established for a single-stage induction cell and an induction voltage adder (IVA) with three cells stacked in series, without considering electron emission. By means of these two models, some factors affecting the injection current uni- formity are simulated and analyzed, such as the impedances of adders and loads, cell locations, and feed timing of parallel driving pulses. Simulation results indicate that higher impedances of adder and loads are slightly beneficial to improve injection current uniformity. As the impedances of adder and loads increase from 5 Ω to 30Ω, the asymmetric coefficient of feed currents decreases from 10.3% to 6.6%. The current non-uniformity within the first cell is a little worse than that in other downstream cells. Simulation results also show that the feed timing would greatly affect current waveforms, and consequently cause some distortion in pulse fronts of cell output voltages. For a given driving pulse with duration time of 70-80 ns, the feed timing with a time deviation of less than 20 ns is acceptable for the three-cell IVAs, just causing the rise time of output voltages to increase about 5 ns at most and making the peak voltage decrease by 3.5%. 展开更多
关键词 induction voltage adders IVA induction cell single-point feed current uni- formity electromagnetic model
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PET image reconstruction with a system matrix containing point spread function derived from single photon incidence response 被引量:1
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作者 樊馨 王海鹏 +8 位作者 贠明凯 孙校丽 曹学香 刘双全 柴培 李道武 刘宝东 王璐 魏龙 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第1期542-550,共9页
A point spread function(PSF) for the blurring component in positron emission tomography(PET) is studied. The PSF matrix is derived from the single photon incidence response function. A statistical iterative recons... A point spread function(PSF) for the blurring component in positron emission tomography(PET) is studied. The PSF matrix is derived from the single photon incidence response function. A statistical iterative reconstruction(IR) method based on the system matrix containing the PSF is developed. More specifically, the gamma photon incidence upon a crystal array is simulated by Monte Carlo(MC) simulation, and then the single photon incidence response functions are calculated. Subsequently, the single photon incidence response functions are used to compute the coincidence blurring factor according to the physical process of PET coincidence detection. Through weighting the ordinary system matrix response by the coincidence blurring factors, the IR system matrix containing the PSF is finally established. By using this system matrix, the image is reconstructed by an ordered subset expectation maximization(OSEM) algorithm. The experimental results show that the proposed system matrix can substantially improve the image radial resolution, contrast,and noise property. Furthermore, the simulated single gamma-ray incidence response function depends only on the crystal configuration, so the method could be extended to any PET scanner with the same detector crystal configuration. 展开更多
关键词 point spread function single photon incidence system matrix positron emission tomography
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Investigation of Surface Micro Waviness in Single Point Diamond Fly Cutting 被引量:1
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作者 Sheng-Fei Wang Peng-Qiang Fu +2 位作者 Fei-Hu Zhang Chen-Hui An Yong Zhang 《Journal of Harbin Institute of Technology(New Series)》 EI CAS 2014年第5期119-123,共5页
Single point diamond fly cutting is widely used in the manufacture of large-aperture ultra-precision optical elements. However,some micro waviness( amplitude about 30 nm,wavelength about 15 mm) along the cutting direc... Single point diamond fly cutting is widely used in the manufacture of large-aperture ultra-precision optical elements. However,some micro waviness( amplitude about 30 nm,wavelength about 15 mm) along the cutting direction which will decrease the quality of the optical elements can always be found in the processed surface,and the axial vibration of the spindle caused by the cut-in process is speculated as the immediate cause of this waviness. In this paper,the analytical method of dynamic mesh is applied for simulating the dynamic behavior of the vertical spindle. The consequence is then exerted to the fly cutter and the processed surface profile is simulated. The wavelength of the simulation result coincides well with the experimental result which proves the importance of the cut-in process during the single point diamond fly cutting. 展开更多
关键词 surface waviness surface profile spindle dynamic behavior single point diamond fly cutting
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Simple and Efficient Cultivation Technology for the Peanut under the Standardization Mode of Single-seed Sowing 被引量:1
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作者 Hao FENG Zhengfeng WU +6 位作者 Jiancai LIN Tianyi YU Yongmei ZHENG Xuewu SUN Pu SHEN Chengren SHI Caibin WANG 《Asian Agricultural Research》 2016年第6期61-64,共4页
Single-seed sowing is a new,simple and efficient cultivation mode for peanut that realized from cultivation of healthy individual and construction of high-yielding population. The cultivation mode has the obvious adva... Single-seed sowing is a new,simple and efficient cultivation mode for peanut that realized from cultivation of healthy individual and construction of high-yielding population. The cultivation mode has the obvious advantages in uniform seedling,strong sprouting,seed saving and cost saving,thus it is considered as one of the effective ways for high-yield and high-efficient peanut cultivation in China in the future.Through integrating with other high-efficiency and simple cultivation measures,the single-seed sowing technology system has made conforming to China's national standardization cultivations of peanut and the technology was already applied in the main producing areas of peanut and gained the significant efficiency and abroad application prospects. Based on many years of researches in single-seed sowing technology,high-efficiency fertilization and scientific chemical control in the research team,by combining with the latest research results in plant protection and machinery,this paper described the key points and matters needing attentions from variety selection,planting mode,rational fertilization,planting specifications and field management. 展开更多
关键词 PEANUT single-seed SOWING High efficient CULTIVATION Technical pointS
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The Structure of Background-error Covariance in a Four-dimensional Variational Data Assimilation System:Single-point Experiment 被引量:2
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作者 刘娟娟 王斌 王曙东 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2010年第6期1303-1310,共8页
A four dimensional variational data assimilation (4DVar) based on a dimension-reduced projection (DRP-4DVar) has been developed as a hybrid of the 4DVar and Ensemble Kalman filter (EnKF) concepts. Its good flow-... A four dimensional variational data assimilation (4DVar) based on a dimension-reduced projection (DRP-4DVar) has been developed as a hybrid of the 4DVar and Ensemble Kalman filter (EnKF) concepts. Its good flow-dependent features are demonstrated in single-point experiments through comparisons with adjointbased 4DVar and three-dimensional variational data (3DVar) assimilations using the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5). The results reveal that DRP-4DVar can reasonably generate a background error covariance matrix (simply B-matrix) during the assimilation window from an initial estimation using a number of initial condition dependent historical forecast samples. In contrast, flow-dependence in the B-matrix of MM5 4DVar is barely detectable. It is argued that use of diagonal estimation in the B-matrix of the MM5 4DVar method at the initial time leads to this failure. The experiments also show that the increments produced by DRP-4DVar are anisotropic and no longer symmetric with respect to observation location due to the effects of the weather trends captured in its B-matrix. This differs from the MM5 3DVar which does not consider the influence of heterogeneous forcing on the correlation structure of the B-matrix, a condition that is realistic for many situations. Thus, the MM5 3DVar assimilation could only present an isotropic and homogeneous structure in its increments. 展开更多
关键词 DRP-4DVar data assimilation flow dependence single-point experiment
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