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Step kinematic calibration of a 3-DOF planar parallel kinematic machine tool

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Science china(Technological Sciences) 2008年第12期51卷 2155-2167页

作者： CHANG Peng,wang JinSong,LI TieMin,LIU XinJun & GUAN LiWen department of Precision {2. and Mechanology,tsinghua university,beijing 100084,china 1. department of Precision instruments and Mechanology Tsinghua University Beijing 100084 China

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 *** 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 *** using the four theorems of the MLCs,the sets of the MLCs that are respectively related to the relative precision and absolute precision are *** simple and feasible measurement methods in practice are given,and identification analysis of the set of the MLCs for each measurement is carried *** 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 *** 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 *** 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.

关键词： parallel kinematic machine tools kinematic calibration parameter identification minimal linear combinations

Holographic Storage Parametric Optimization of the Crystal LiNbO3∶Fe Based on One-center Model

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Chinese Journal of Lasers 2002年第1期11卷 28-34页

作者： wang Jiangang HE Qingsheng JIN Guofan WU Minxian (State Key Laboratory of Precision Measurement Technology and instruments, {2. of Precision instruments, tsinghua university, beijing 100084, china) department of Precision instruments Tsinghua University State Key Laboratory of Precision Measurement Technology and Instruments 北京 100084

Based on one-center model, the effects of the doping amount and the degrees of reduction and oxidation on the dynamic range M, the response time and the photorefractive sensitivity in the crystal LiNbO 3∶Fe are analyzed in detail. The principle of material optimization is discussed. The best crystal thickness (about 1.4～2.6 mm) for the maximum dynamic range M is calculated for the different doping amounts. The results show that the more the doping amount, the lighter the reduction of the crystal should be chosen, and that the heavier the reduction of the crystal, the less effect the doping amount has on the response time. The dynamic range M is in conflict with the response time. Due to the difficulty of processing crystals, the thickness is increased to 5 mm at the cost of decreasing the dynamic range M by 0.3～0.5.

关键词： holographic storage materials parametric optimization LiNbO 3∶Fe crystals

Advanced　Heterodyne　Interferometer　with　Common　Path　for　Roughness　Measurement

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Chinese Journal of Lasers 1995年第3期B4卷 257-261页

作者： LI Xiang wang Jia ZHAO Yang LI Dacheng CAO Mang(department of Precision {2., tsinghua university beijing 100084, china) tsinghua Univ Beijing China

ＡｄｖａｎｃｅｄＨｅｔｅｒｏｄｙｎｅＩｎｔｅｒｆｅｒｏｍｅｔｅｒｗｉｔｈＣｏｍｍｏｎＰａｔｈｆｏｒＲｏｕｇｈｎｅｓｓＭｅａｓｕｒｅｍｅｎｔ￥ＬＩＸｉａｎｇ；ＷＡＮＧＪｉａ；ＺＨＡＯＹａｎｇ；ＬＩＤａｃｈｅｎｇ；ＣＡＯ... 详细信息

ＡｄｖａｎｃｅｄＨｅｔｅｒｏｄｙｎｅＩｎｔｅｒｆｅｒｏｍｅｔｅｒｗｉｔｈＣｏｍｍｏｎＰａｔｈｆｏｒＲｏｕｇｈｎｅｓｓＭｅａｓｕｒｅｍｅｎｔ￥ＬＩＸｉａｎｇ；ＷＡＮＧＪｉａ；ＺＨＡＯＹａｎｇ；ＬＩＤａｃｈｅｎｇ；ＣＡＯＭａｎｇ（Ｄｅｐａｒｔｍｅｎｔｏｆ...

关键词： roughness measurement common path heterodyne interferometers

Laser Measuring System Used for Large Workpiece Diameter

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Chinese Journal of Lasers 1996年第1期B5卷 94-96页

作者： ZHANG Jianmin wang Jia LI Dacheng CAO Mang ZHAO Yang(department of Precision {2.,tsinghua university,beijing 100084, china) tsinghua Univ Beijing China

This paper reports a new kind of laser measuring instrument applied to detect large diameters of a workpiece on the production floor. The measuring principle of the instrument is specified in detail.

关键词： diameter measurement laser CCD

Study on simulation and experiment of array micro Faraday cup ion detector for FAIMS

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Science china(Technological Sciences) 2010年第12期53卷 3225-3231页

作者： TANG Fei, wang XiaoHao, ZHANG Liang & YAN ZiLin State Key Laboratory of Precision Measurement Technology and instruments, {2. of Precision instruments and Mechanology, tsinghua university, beijing 100084, china 1. State Key Laboratory of Precision Measurement Technology and instruments Department of Precision Instruments and Mechanology Tsinghua University Beijing 100084 China

An array micro Faraday cup ion detector for FAIMS (High-field Asymmetric Waveform Ion Mobility Spectrometry) was introduced, with which the size of the FAIMS system was reduced. With simple structure, good stability, low noise, large measurements range, this detector can work under the condition of atmospheric pressure. The array micro Faraday cup was composed of gate electrode, sensitive electrode and shielding electrode. The sensitive electrode was made of tens of crossing silicon columns with diameter of 2.0 μm. It was fabricated through typical MEMS technology, which was compatible completely with plane FAIMS. It was shown from FLUENT simulation result that the resistance to gas motion was low and the flow field distribution was helpful for full absorption of the ion in this array design. Through electricity simulation, the method to reduce interference on the detection signal of the micro Faraday cup was given out. Connecting with KEITHLEY 2.7 ampere meter, the noise level of the array micro Faraday cup was lower than 0.5 pA. The output signal of the acetone sample measured by experiment was about 2.0 pA. Through contrast experiment, the design parameter of the micro Faraday cup was obtained primarily. This array micro Faraday cup can meet the requirements of the FAIMS system.

关键词： FAIMS MEMS Faraday cup ion detector low current

Clinical significance,molecular characterization,and immune microenvironment analysis of coagulation-related genes in clear cell renal cell carcinoma

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Cancer Innovation 2024年第1期3卷 29-49页

作者： Weihao Chen Xupeng Zhao yongliang Lu Hanfeng wang Xiyou wang Yi wang Chen Liang Zhuomin Jia Wei Ma department of Urology The Third Medical Center of PLA General HospitalBeijingChina School of Medicine Nankai UniversityTianjinChina Medical Service department The PLA General HospitalBeijingChina Senior department of Otolaryngology-Head&Neck Surgery The Sixth Medical Center of PLA General HospitalBeijingChina

Background:Numerous studies have revealed a tight connection between tumor development and the coagulation ***,the effects of coagulation on the prognosis and tumor microenvironment(TME)of clear cell renal cell carcinoma(ccRCC)remain poorly ***:We employed the consensus clustering method to characterize distinct molecular subtypes associated with coagulation ***quently,we examined variations in the overall survival(OS),genomic profiles,and TME characteristics between these *** develop a prognostic coagulation-related risk score(CRRS)model,we utilized the least absolute shrinkage and selection operator Cox regression and stepwise multivariate Cox regression *** also created a nomogram to aid in the clinical application of the risk score,evaluating the relationships between the CRRS and the immune microenvironment,responsiveness to immunotherapy,and targeted *** clinical significance of PLAUR and its biological function in ccRCC were also further ***:There were significant differences in clinical features,prognostic stratification,genomic variation,and TME characteristics between the two coagulation-related *** established and validated a CRRS using six coagulation-related genes that can be employed as an effective indicator of risk stratification and prognosis estimation for ccRCC *** variations in survival outcomes were observed between the high-and low-risk *** nomogram was proficient in predicting the 1-,3-,and 5-year ***,the CRRS emerged as a novel tool for evaluating the clinical effectiveness of immunotherapy and targeted treatments in ***,we confirmed upregulated PLAUR expression in ccRCC samples that was significantly correlated with poor patient *** knockdown notably inhibited ccRCC cell proliferation and ***:Our data suggested that CRRS may be employed as a reliable predictive biomarker that can pro

关键词： clear cell renal cell carcinoma coagulation immunotherapy risk score tumor immune microenvironment

Effect of Fluid Electrical Property Changes on Surface Transverse Wave Sensors

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稀有金属材料与工程 2006年第S3期 514-518页

作者： Chao Zhang~1 Wenyan wang~2.Yonggui Dong~2.Yan Liu~1 Guanping Feng~1 (1.Research Institute of tsinghua university in Shenzhen,Shenzhen 518057,{2.) (2.department of Precision instruments and Mechanology,tsinghua university,beijing 100084,{2.)

A fluid sensor based on the surface transverse wave (STW) delay line on ST-cut quartz has been developed and tested in a large number of fluids with different viscosity and permittivity *** of fluid mechanical and electrical properties on the sensor's response has been determined and the sensor's performance has been compared with a bulk acoustic wave (BAW) viscosity *** result shows that the viscosity sensitivity of the developed STW sensor represented by the signal to noise ratio is lower than that of a 5 MHz BAW *** of the sensor in detecting the quality of industrial fluids are discussed.

关键词： surface transverse wave surface acoustic wave fluid sensor electrical property

A Novel CAPP System Based on SML for Variant Design of Process Planning

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武汉理工大学学报 2006年第S3期28卷 820-823页

作者： ZHAO Haibin~1 wang Junying~1 ZHANG Min~2.(1.department of Precision {2. & Mechanology,tsinghua university,beijing 100084,china, 2.department of Mechanical Equipment & Control Engineering,beijing university of Science and Technology,Bejing 100083,china) department of Precision instruments & Mechanology Tsinghua UniversityBeijing 100084China department of Mechanical Equipment & Control Engineering Beijing University of Science and TechnologyBejing 100083 China

The production model of“multi-specification and low-quantity”is becoming the main trend of manufacturing *** a key activity in the manufacturing chain,traditional computer aided process planning(CAPP)system fails to adapt to the production model of ***,a novel method for variant design of process planning was proposed to develop CAPP system based on Tabular Layouts of Article Characteristics(Sach-Merk Leisten in German and SML for short). With the support of standard database of master process planning documents which are developed by parameterization technique, and instance process planning for special product(instance product)can be generated automatically by the sub-system of variant de- sign of process ***,a CAPP system was developed for process design of rotor of steam turbine to validate the feasibil- ity and applicability of the method.

关键词： CAPP variant design SML master process planning documents(DocMPP) parameterization

Laparoscopic versus open surgery in treating patients with gallbladder cancer: a systematic review and meta-analysis

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Hepatobiliary Surgery and Nutrition 2024年第3期13卷 444-459,I0012-I0014页

作者： Duo Li Li Xu Xiangling Deng yongliang Sun Zihuan Zhang Tianxiao wang Ruili Wei Yingjixing Luo Wenquan Niu Zhiying Yang Graduate School Peking Union Medical College and Chinese Academy of Medical SciencesBeijingChina department of General Surgery China-Japan Friendship HospitalBeijingChina Graduate School Beijing University of Chinese MedicineBeijingChina department of Pediatrics China-Japan Friendship HospitalBeijingChina Graduate School Peking University Health Science CenterBeijingChina Graduate School Capital Medical UniversityBeijingChina Center for Evidence-Based Medicine Capital Institute of PediatricsBeijingChina

Background:Concerns over the security of laparoscopic radical operation for gallbladder cancer(GBC)*** systematic review and meta-analysis attempted to compare the safety and efficacy of laparoscopic surgery(LS)versus open surgery(OS)in the treatment of ***:The PubMed,EMBASE,and Web of Science were searched from inception to July 18,*** search,quality assessment,and data extraction were completed independently and in ***-size estimates expressed as weighted mean difference(WMD)or odds ratio(OR)with 95%confidence interval(CI)were derived under the random-effects ***:A total of 2. independent studies including 2.868 participants were *** was noted for intraoperative blood loss(WMD:−117.194,95%CI:−170.188 to 64.2.1,P2.,95%CI:−1.776 to−0.2.9,P=0.008),postoperative hospital stay(WMD:−3.555,95%CI:−4.509 to−2.601,P2.year(OR:1.52.,95%CI:1.143 to 2.031,P=0.004),T2.survival at 1-year(OR:1.799,95%CI:1.777 to 2.749,P2.year(OR:2.02.,95%CI:1.392.to 2.949,P2.669,95%CI:1.564 to 4.555,P2.year(OR:2.300,95%CI:1.308 to 4.046,P=0.004).Subgroup analyses revealed that ethnicity,incidental GBC,sample size,and follow-up period were possible sources of *** was a low probability of publication bias for all outcomes except postoperative ***:Our findings indicated that LS statistically had better 2.year survival rates,less intraoperative bleeding,shorter hospitalization times,and lower rates of complications than ***,the superiority and even the safety of LS still remain an open question due to the impact of incidental GBC,unaccounted heterogeneity,publication bias,lymph node dissection,and port-site metastasis.

关键词： Systematic review and meta-analysis gallbladder cancer(GBC) laparoscopic surgery(LS) open surgery survival