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Grasp evaluation and contact points planning for polyhedral objects using a ray-shooting algorithm

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第3期13卷 218-231页

作者： Shuang-quan WEN Tie-jun wu Department of Control Science and Engineering Zhejiang UniversityHangzhou 310027China

Grasp evaluation and planning are two fundamental issues in robotic grasping and dexterous manipulation. Most traditional methods for grasp quality evaluation suffer from non-uniformity of the wrench space and a dependence on the scale and choice of the reference frame. To overcome these weaknesses, we present a grasp evaluation method based on disturbance force rejection under the assumption that the normal component of each individual contact force is less than one. The evaluation criterion is solved using an enhanced ray-shooting algorithm in which the geometry of the grasp wrench space is read by the support mapping. This evaluation procedure is very fast due to the efficiency of the ray-shooting algorithm without linearization of the friction cones. Based on a necessary condition for grasp quality improvement, a heuristic searching algorithm for polyhedral object regrasp is also proposed. It starts from an initial force-closure unit grasp configuration and iteratively improves the grasp quality to find the locally optimum contact points. The efficiency and effectiveness of the proposed algorithms are illustrated by a number of numerical examples.

关键词： Force closure Grasp quality evaluation Multifingered grasp Grasping planning Ray-shooting

Identification of miRNAs and their targets in tea (Camellia sinensis)

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2013年第10期14卷 916-923页

作者： quan-wu ZHU Yao-ping LUO Institute of Tea Science Zhejiang University

MicroRNAs(miRNAs) are endogenous small RNAs playing a crucial role in plant growth and development,as well as stress *** them,some are highly evolutionally conserved in the plant kingdom,this provide a powerful strategy for identifying miRNAs in a new ***(Camellia sinensis) is one of the most important commercial beverage crops in the world,but only a limited number of miRNAs have been *** the present study,a total of 14 new *** miRNAs were identified by expressed sequence tag(EST) analysis from 47 452 available *** *** miRNAs potentially target 51 mRNAs,which can act as transcription factors,and participate in stress response,transmembrane transport,and signal *** of gene ontology(GO),based on these targets,suggested that 37 biological processes were involved,such as oxidation-reduction process,stress response,and *** Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analysis inferred that the identified miRNAs took part in 13 metabolic *** study will help further understanding of the essential roles of miRNAs in *** growth and development,and stress response.

关键词： MicroRNA(miRNA) Camellia sinensis Tea Gene ontology Pathway

In-situ cation exchange enhances room temperature phosphorescence of a family of metal-organic frameworks

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Science China Chemistry 2022年第1期65卷 128-134页

作者： Rui Feng zi-Ying Li Zhao-quan Yao zi-Ang Guo Yi-Nan Zhang Hao-Xiang Sun Wei Li Xian-He Bu College of Chemistry State Key Laboratory of Elemento-Organic ChemistryNankai UniversityTianjin 300071China School of Materials Science and Engineering Tianjin Key Laboratory of Metal and Molecule-Based Material ChemistryNankai UniversityTianjin 300350China

The rational designability and chemical tunability of metal-organic frameworks(MOFs)are enabling tributes to efficaciously enhance their room temperature phosphorescence(RTP)performance.A family of stable anionic MOFs,[Zn_(2)(4,5-ImDC)_(2)]M_(2)(NKU-132,M=(CH_(3))_(2)NH_(2)or(CH_(2)CH_(3))_(2)NH_(2)),featuring significant RTP have been *** rational cation selection and in-situ replacement from dimethylammonium to diethylammonium,the phosphorescence lifetime is increased from 30.88 to126.3 ms,along with less sensitivity to *** work provides an anti-quenching and lifetime tuning example for RTP-MOFmaterials via facile host-guest chemistry.

关键词： metal-organic framework room temperature phosphorescence crystal engineering in situ regulation

The dynamic change of pore structure for low-rank coal under refined upgrading pretreatment temperatures

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Petroleum Science 2021年第2期18卷 430-443页

作者： Teng Li Cai-Fang wu zi-Wei Wang College of Petroleum Engineering Xi’an Shiyou UniversityXi’an710065ShaanxiChina Shandong Key Laboratory of Depositional Mineralization and Sedimentary Mineral Shandong University of Science and TechnologyQingdao266590ShandongChina Shaanxi Key Laboratory of Advanced Stimulation Technology for Oil and Gas Reservoirs Xi’an Shiyou UniversityXi’an710065ShaanxiChina School of Resources and Geosciences China University of Mining and TechnologyXuzhou221008JiangsuChina

Pore structure characteristics are significant factor in the evaluation of the physical characteristics of low-rank *** this study,three low-rank coal samples were collected from the Xishanyao Formation,Santanghu Basin,and low-temperature liquid-nitrogen adsorption(LP-N2A)measurements were taken under various pretreatment *** to the continuous loss of water and volatile matter in low-rank coal,the total pore volume assumes a three-step profile with knee temperatures of 150°C and 240°***,the ash in the coal can protect the coal *** collapse mainly occurs for mesopores with aperture smaller than 20 *** with apertures smaller than 5 nm exhibit a continuous decrease in pore volume,whereas the pore volume of mesopores with apertures ranging from 5 to 10 nm increases at lower pretreatment temperatures(<150°C)followed by a faint *** for mesopores with apertures larger than 10 nm,the pore volume increases significantly when the pretreatment temperature reaches 300°*** pore structure of low-rank coal features a significant heating effect,the pretreatment temperature should not exceed 150°C when the LP-N2A is used to evaluate the pore structure of low-rank coal to effectively evaluate the reservoir characteristics of low-rank coal.

关键词： Low-rank coal Low-temperature liquid-nitrogen adsorption Pore structure Refined upgrading temperatures Heating effect

Mlock:building delegable metadata service for the parallel file systems

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Science China(Information Sciences) 2015年第3期58卷 66-79页

作者： ZHANG quan FENG Dan WANG Fang wu Sen wuhan National Laboratory for Optoelectronics School of Computer Huazhong University of Science and Technology Information & Telecommunication Company State Grid Hubei Electric Power Company

The ever-growing demand for high performance computation calls for progressively larger parallel distributed file systems to match their *** file systems can achieve high performance for large I/O operations through distributing load across numerous data ***,they fail to provide quality service for applications pertaining to small *** this paper,we propose a delegable metadata service(DMS)for hiding latency of metadata accesses and optimizing small-file *** addition,four techniques have been designed to maintain consistency and efficiency in DMS:pre-allocate serial metahandles,directory-based metadata replacement,packing transaction operations and fine-grained lock *** schemes have been employed in Cappella parallel distributed file system,and various experiments complying with industrial standards have been conducted for evaluation of its *** results show that our design has achieved significant improvement in performance of both metadata operations and small-file ***,this scheme is widely applicable for integration within many other distributed file systems.

关键词： delegable metadata service metadata performance consistency small file parallel file system

Both small and large plants are likely to produce staminate(male)flowers in a hermaphrodite lily

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Plant Diversity 2020年第3期42卷 142-147页

作者： EiEi Shwe Bo wu Shuang-quan Huang Institute of Evolution and Ecology School of Life SciencesCentral China Normal University152 Luoyu AvenueHongshan DistrictWuhan430079China

Resource allocation to female and male function may vary among individual plants in species with variable sex ***-dependent sex allocation has been proposed in hermaphrodites,in which female-biased allocation may increase with plant *** many hermaphrodites with large floral displays,however,later-produced flowers tend to be functionally *** paradoxical relationship between female and male function and plant size remains poorly *** subalpine lily Lilium lankongense has individuals of three sexual types:males with only staminate flowers,hermaphrodites with only perfect flowers,and andromonoecious plants with both perfect and staminate *** we tested theoretical predictions of size-dependent sex allocation in *** by measuring plant height and flower number of individuals of each sex at five field sites in the mountainous region of Shangri-La,southwestern *** investigate variation in phenotypic gender,we identified sex expression of 457 individuals one year *** investigation showed that male plants,which usually produced one flower,were significantly smaller than and ro monoecious and hermaphrodite *** addition,the total flower numbers of andromonoecious and hermaphrodite plants increased significantly with plant *** individuals were more likely to produce terminal staminate flowers,as there were more flowers in andromonoecious than in hermaphrodite ***-flowered plants were significantly smaller than flowering *** flowers had significantly larger petals and pistils than staminate flowers,but they did not differ in dry weight of *** findings indicate that when plants are small,the less costly sex is favored,consistent with the‘size-advantage hypothesis’.When plants are large,both female and male investments change isometrically,as later-produced flowers tend to be functionally male.

关键词： Andromonoecy Plant size Lilium lankongense Phenotypic gender Size-dependent sex allocation Staminate flower

The clinicopathological and prognostic significance of PD-L1 expression in pancreatic cancer:A meta-analysis

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Hepatobiliary & Pancreatic Diseases International 2018年第2期17卷 95-100页

作者： He-Li Gaoa Liang Liua zi-Hao Qi Hua-Xiang Xu Wen-quan Wang Chun-Tao wu Shi-Rong Zhang Jin-Zhi Xu quan-Xing Ni Xian-Jun Yua Department of Pancreatic Surgery Fudan University Shanghai Cancer CenterShanghai 200032China Department of Oncology Shanghai Medical CollegeFudan UniversityShanghai 200032China Shanghai Pancreatic Cancer Institute Shanghai 200032China Pancreatic Cancer Institute Fudan UniversityShanghai 200032China

Background: Immunotherapy has shown promise against solid tumors. However, the clinical significance of programmed cell death 1(PD-1) and programmed cell death ligand 1(PD-L1) in pancreatic ductal adenocarcinoma(PDAC) remains unclear. This meta-analysis aimed to analyze the prognostic effect of PD-L1 in *** sources: Electronic search of the Pub Med, Cochrane Library and Web of Science was performed until December 2016. Through database searches, we identified articles describing the relationship between PD-L1 status and PDAC patient prognosis. Meta-analysis was performed to investigate the relationship between PD-1 and overall survival(OS).Results: Nine studies with 989 PDAC patients were included for PD-L1 expression analysis. And 5 studies with 688 PDAC patients were included in the prognostic analysis. The PD-L1 positive rate measured by immunohistochemistry(IHC) was higher than that measured by polymerase chain reaction(PCR)(P < 0.001). PDAC patients with high expression levels of PD-L1 had significantly reduced OS(HR = 2.34;95% CI: 1.78–3.08). Subgroup analysis showed that the prognostic effect of PD-L1 levels was similar between the IHC and PCR methods. The PD-L1 positive rate was associated with PDAC T stages; the PD-L1 positive rate in the T3–4 group was higher than that in the T1-2 group(OR = 0.37; P = 0.001).Conclusions: High PD-L1 expression levels predicted a poor prognosis in PDAC patients. Thus, PD-L1 status helps determine treatment in PDAC patients.

关键词： Pancreatic ductal adenocarcinoma Programmed cell death ligand 1 Prognosis Meta-analysis

Tensile properties and fractographs of Ti–2.5Al–1.5Mn foils at different temperatures

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Rare Metals 2017年第4期36卷 247-255页

作者： Zhen-wu Ma Guo-quan Tong Feng Chen College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016China

The tensile properties and fractographs of Ti- 2.5Al-1.5Mn foils at different temperatures were investi- gated. It is observed that material properties closely cor- relate with the thickness （T） to grain size （d） ratio and deformation temperature. Tensile analysis shows that local deformation is the main deformation feature in foils forming at room temperature, which may lead to premature fracture. The causes of inhomogeneous deformation behavior are the limited number of deformable grains contained in deformation zone and the weak transferability of hardening among different grains. Fracture analysis reveals that the size of dimples can represent the ductility of foils at room temperature. With the further increase of deformation temperature, the main plastic deformation mode of foils is transformed from intragranular disloca- tions and twin crystal to grain-boundary gliding and roll- ing. In conclusion, foil forming at elevated temperature can increase the hardening transferability and the number of deformable grains in deformation zone, which is an effective method to improve the formability and reduce the scatter of material properties.

关键词： Size effects Titanium foils Tensile properties Homogeneous deformation Elevated temperature

Characteristics of shell thickness in a slab continuous casting mold

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International Journal of Minerals,Metallurgy and Materials 2009年第1期16卷 25-31页

作者： Di-feng wu Shu-sen Cheng zi-jian Cheng School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Steelmaking Plant Jiuquan Iron and Steel Co. Ltd. Jiayuguan 735100 China

The key to reduce shell breakout in the continuous casting process is to control shell thickness in the mold. A numerical simulation on the turbulent flow and heat transfer coupled with solidification in the slab mold using the volume of fluid （VOF） model and the enthalpy-porosity scheme was conducted and the emphasis was put upon the flow effect on the shell thickness profiles in longitudinal and transverse directions. The results show that the jet acts a stronger impingement on the shell of narrow face, which causes a zero-increase of shell thickness in a certain range near the impingement point. The thinnest shell on the slab cross-section locates primarily in the center of the narrow face, and secondly near the comer of the wide face. Nozzle optimization can obviously increase the shell thickness and make it more uniform.

关键词： continuous casting slab mold shell thickness nozzle optimization