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Effect of PCBN cutting tools wear on surface integrality in high-speed hard turning

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High Technology Letters 2012年第2期18卷 128-131页

作者：陈涛 liu xian li Mechanical&Power Engineering College Harbin University of Science and TechnologyHarbin 150080P.R.China

In this paper, the effect of of flank wear polycrystalline cubic boron nitride （PCBN） tools on residual stresses, white layer and roughness of machined workpiece surfaces is studied. Experimental results indicate that with the increase of the tool wear, the surface of the machined workpiece tends to generate tensile residual stresses, and white layer becomes clearly thicker and uneven on the workpiece surface. The effect of the flank wear on the surface roughness is less within some range of flank wear value. The results show that it is possible to produce ideal surface integrality levels by controlling the tool flank wear.

关键词： polycrystalline cubic boron nitride(PCBN) flank wear high-speed precision hard turning surface integrity

Understanding and Generating Ultrasound Image Description

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Journal of Computer Science & Technology 2018年第5期33卷 1086-1100页

作者： xian-Huu Zeng Bang-Gui liu Meng Zhou School of Computer Science and Technology Chongqing University of Posts and Telecommunications Chongqing 400065 China

To understand the content of ultrasound images more conveniently and more quickly, in this paper, we propose a coarse-to-fine ultrasound image captioning ensemble model, which can automatically generate the annotation text that is composed of relevant n-grams to describe the disease information in the ultrasound images. First, the organs in the ultrasound images are detected by the coarse classification model. Second, the ultrasound images are encoded by the corresponding fine-grained classification model according to the organ labels. Finally, we input the encoding vectors to the language generation model, and the language generation model generates automatically annotation text to describe the disease information in the ultrasound images. In our experiments, the encoding model can obtain the high accuracy rate in the ultrasound image recognition. And the language generation model can automatically generate high-quality annotation text. In practical applications, the coarse-to-fine ultrasound image captioning ensemble model can help patients and doctors obtain the well understanding of the contents of ultrasound images.

关键词： ultrasound image fine-grained classification image captioning

Enhanced Electromagnetic Interference Shielding of Mg–Zn–Zr Alloy by Ce Addition

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Acta Metallurgica Sinica(English Letters) 2015年第4期28卷 492-498页

作者： xian-Hua Chen Li-Zi liu Juan liu Fu-Sheng Pan College of Materials Science and Engineering Chongqing University National Engineering Research Center for Magnesium Alloys Chongqing University Chongqing Academy of Science and Technology

The effects of Ce addition on microstructure and electromagnetic interference （EMI） shielding response of Mg- 6Zn-0.5Zr （ZK60） alloy have been investigated. Ce addition resulted in grain refinement and higher density of Mg-Zn-Ce and MgZn2 intermetallic particles in the alloy. In particular, this was substantially remarkable as the addition of Ce was up to 1.0 wt%. It is interesting to note that as-extruded ZK60 alloy with 1.0 wt% Ce addition exhibited an EMI shielding effectiveness （SE） exceeding 70 dB at the frequency range of 30-1,500 MHz, which was significantly higher than that of ZK60 alloy without Ce addition and reached the requirement of high protection. The superior SE was probably related to the increased reflection and multiple reflection of electromagnetic radiation induced by Ce addition. Direct artificial aging at 150 ℃ for 25 or 50 h led to a further increase of 7-10 dB in the SE of the alloy with 1.0 wt% Ce addition. The advantages of excellent shielding capacity and favorable mechanical strength make the Mg-Zn-Zr-Ce alloy an attractive shielding candidate material for a variety of technological applications.

关键词： Magnesium alloys Ce Shielding effectiveness Electromagnetic interference Intermetallicparticles

D-optimal Designs for Multiresponse Linear Models with a Qualitative Factor Under General Covariance Structure

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Acta Mathematicae Applicatae Sinica 2023年第4期39卷 878-885页

作者： Rong-xian YUE Xin liu Kashinath CHATTERJEE College of Mathematics and Science Shanghai Normal UniversityShanghai 200234China College of Science Donghua UniversityShanghai 201620China Department of Statistics Visva-Bharati UniversitySantiniketanIndia

This paper considers a linear regression model involving both quantitative and qualitative factors and an m-dimensional response variable y. The main purpose of this paper is to investigate D-optimal designs when the levels of the qualitative factors interact with the levels of the quantitative factors. Under a general covariance structure of the response vector y, here we establish that the determinant of the information matrix of a product design can be separated into two parts corresponding to the two marginal designs. Moreover, it is also proved that D-optimal designs do not depend on the covariance structure if we assume hierarchically ordered system of regression models.

关键词： D-optimal designs Multiresponse linear models Qualitative factors

Induction of Somatic Embryos in Arabidopsis Requires Local YUCCA Expression Mediated by the Down-Regulation of Ethylene Biosynthesis

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Molecular Plant 2013年第4期6卷 1247-1260页

作者： Bo Bai Ying Hua su Jia Yuan xian Sheng Zhang State Key Laboratory of Crop Biology College of Life Sciences Shandong Agricultural University Taian Shandong 271018 China

Somatic embryogenesis is an important experimental model for studying cellular and molecular mechanisms of early embryo development. Although it has long been known that removal of exogenous auxin from medium results in somatic embryogenesis, the mechanisms underlying the initiation of somatic embryos （SEs） are poorly understood. In this study, we showed that YUCCAs （YUCs） encoding key enzymes in auxin biosynthesis are required for SE induction in Arabidopsis. To identify other factors mediating SE initiation, we performed transcriptional profiling and gene expres- sion analysis. The results showed that genes involved in ethylene biosynthesis and its responses were down-regulated during SE initiation. Ethylene level decreased progressively during SE initiation, whereas treatment with the metabolic precursor of ethylene, 1-aminocyclopropane-l-carboxylic acid （ACC）, or mutation of ETHYLENE-OVERPRODUCTION1 （ET01） disrupted SE induction, suggesting that ethylene plays a role in this process. suppression of SE induction was also observed in the constitutive triple response 1 （ctrl） mutant, in which ethylene signaling was enhanced. These results indicate that down-regulation of not only ethylene biosynthesis, but also ethylene response is critical for SE induction. We further showed that ethylene disturbed SE initiation through inhibiting YUC expression that might be involved in local auxin biosynthesis and subsequent auxin distribution. Our results provide new information on the mechanisms of hormone-regulated SE initiation.

关键词： YUC genes auxin biosynthesis auxin distribution ethylene somatic embryo induction Arabidopsis

Nanoencapsulation of arsenate with nanoscale zero-valent iron(nZVI):A 3D perspective

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Science Bulletin 2018年第24期63卷 1641-1648页

作者： Airong liu Wei Wang Jing liu Rongbing Fu Wei-xian Zhang State Key Laboratory for Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongii UniversityShanghai 200092China School of Chemical Sdence and Engineering Tongji UniversztyShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China

The principal forces driving the efficient enrichment and encapsulation of arsenic(As) into nanoscale zero-valent iron(nZVI) are the disordered arrangement of the atoms and the gradient chemical potentials within the core-shell interface. The chemical compositions and the fine structure of nZVI are characterized with a combination of spherical aberration corrected scanning transmission electron microscopy(Cs-STEM), X-ray energy-dispersive spectroscopy(XEDS), electron energy loss spectroscopy(EELS), and high-resolution X-ray photoelectron spectroscopy(HR-XPS). Atomically resolved EELS at the oxygen K-edge unfolds that the Fe species in nZVI are well stratified from Fe(Ⅲ) oxides in the outermost periphery to a mixed Fe(Ⅲ)/Fe(Ⅱ) interlayer, then Fe(Ⅱ) oxide and the pure Fe(0) phase. Reactions between As(Ⅴ)and nZVI suggest that a well-structured local redox gradient exists within the shell layer, which serves as a thermodynamically favorable conduit for electron transfer from the iron core to the surface-bound As(Ⅴ). HR-XPS with ion sputtering shows that arsenic species shift from As(Ⅴ), As(Ⅲ)/As(Ⅴ) to As(Ⅴ)/As(Ⅲ)/As(0) from the iron oxide shell–water interface to the Fe(0) core. Results reinforce previous work on the efficacy of nZVI for removing and remediating arsenic while the analytical TEM methods are also applicable to the study of environmental interfaces and surface chemistry.

关键词： Arsenate Nanoscale zero-valent iron Spherical aberration corrected scanning transmission electron microscopy X-ray energy-dispersive spectroscopy Electron energy-loss spectroscopy X-ray photoelectron spectroscopy

Cotransport of graphene oxides/reduced graphene oxides with BPA in both bare and iron oxides coated quartz sand

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Science China(Technological Sciences) 2019年第11期62卷 1896-1906页

作者： liu xian Wei LI Meng liu FuYang HE Lei TONG MeiPing School of Environment and Energy Peking University Shenzhen Graduate SchoolShenzhen 518055China Key Laboratory of Water and Sediment Sciences Ministry of EducationCollege of Environment and EnergyPeking UniversityBeijing 100871China

This study investigated the cotransport behaviors of graphene oxides(GO) and reduced graphene oxides(RGO) with bisphenol A(BPA) in porous media in both NaCl(1 and 10 mmol/L) and CaCl2 solutions(0.5 and 1.5 mmol/L) at pH 6.5. Both bare and iron oxides-coated quartz sand were employed as porous media in present study. We found that under all examined solution conditions, the presence of BPA(100 μg/L) did not have obvious influence on the transport of both GO and RGO(8 mg/L as TOC) in both bare and iron oxides-coated quartz sand. Although the dissolved BPAwas the major form dominating the transport behaviors of total BPA in the presence of GO/RGO, yet the GO/RGO-associated BPA(due to the adsorption of BPA onto GO/RGO surfaces) also had some contribution to the transport of total BPA in the presence of GO/RGO in two types of porous ***, due to the different transport behaviors of GO and RGO under different solution conditions, we found that the presence of GO/RGO decreased the transport of total BPA under all examined solution conditions in two types of porous media with the smallest decrease in 1 mmol/L NaCl solutions and the largest in 1.5 mmol/L CaCl2 solutions. The results of this study clearly indicated that when BPA was co-present with GO/RGO, the transport behaviors of GO/RGO in porous media would have great influences on the fate and transport of BPA in natural environments due to their adsorption onto GO/RGO.

关键词： BPA graphene oxides cotransport vehicle effect porous media

脱细胞皮肤基质/聚氨酯混纺纤维支架促进大鼠皮肤缺损的修复

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中国组织工程研究 2025年第4期29卷 745-751页

作者：吴辰江佳慧苏豆刘晨慈超皖南医学院第一附属医院皮肤性病科安徽省芜湖市241001 皖南医学院第一附属医院脊柱外科安徽省芜湖市241001

背景:研究证实,将脱细胞基质与聚合物进行混合纺丝不仅可改善纤维的结构性质,还可保存脱细胞基质的生物学活性,但是目前将聚氨酯与脱细胞皮肤基质进行静电纺丝制备皮肤组织工程支架还没有相关报道。目的:观察脱细胞皮肤基质/聚氨酯混纺... 详细信息

背景:研究证实,将脱细胞基质与聚合物进行混合纺丝不仅可改善纤维的结构性质,还可保存脱细胞基质的生物学活性,但是目前将聚氨酯与脱细胞皮肤基质进行静电纺丝制备皮肤组织工程支架还没有相关报道。目的:观察脱细胞皮肤基质/聚氨酯混纺纤维支架对大鼠皮肤缺损的修复作用。方法:利用静电纺丝技术分别制备聚氨酯静电纺丝纤维支架和脱细胞皮肤基质/聚氨酯混纺纤维支架。扫描电镜下观察纤维结构;将大鼠脂肪间充质干细胞分别接种于两组支架上,扫描电镜下观察支架上的细胞形态。取10只SD大鼠,在每只大鼠背部制作3个1 cm×1 cm的全层皮肤缺损,其中2处缺损分别植入聚氨酯静电纺丝纤维支架(对照组)、脱细胞皮肤基质/聚氨酯混纺纤维支架(实验组),剩余缺损处不植入任何材料(空白对照组)。术后第1,2,3周,观察皮肤创面愈合情况;植入后第3周,进行创面苏木精-伊红染色,计算创面瘢痕面积。结果与结论:①扫描电镜下可见两种静电纺丝纤维均为网状结构,并且大鼠脂肪间充质干细胞在两种支架上沿纤维附着,黏附良好。②随着术后时间的延长,各组皮肤创面逐渐愈合,至术后第3周,实验组、对照组皮肤创面基本愈合,空白对照组创面可见小溃疡形成。皮肤创面苏木精-伊红染色显示,对照组、实验组创面表皮覆盖基本完整,真皮层内可见成纤维细胞长入和炎症细胞浸润,并且实验组创面胶原纤维较为丰富、排列规则有序,与表皮面基本平行;空白对照组创面表皮仍有缺损。实验组创面瘢痕面积小于其他两组(P<0.05,P<0.01)。③结果表明,脱细胞皮肤基质/聚氨酯混纺纤维支架可以有效修复大鼠全层皮肤缺损、改善创面瘢痕形成。

关键词：脱细胞皮肤基质聚氨酯静电纺丝皮肤缺损瘢痕

The carotenoid characteristics of the important wild shrimp Trachysalambria curvirostris(Stimpson,1860) in China

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Journal of Oceanology and Limnology 2019年第2期37卷 706-712页

作者： su Fang liu Jianguo CAS Key Laboratory of Experimental Marine Biology Center for Ocean Mega-Science Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 China Laboratory for Marine Biology and Biotechnology Qingdao National Laboratory for Marine Science and Technology Qingdao 266071 China University of Chinese Academy of Sciences Beijing 100049 China

Trachysalambria curvirostris is an economically important shrimp in the coastal waters of the Western Indo-Pacific. However, there is no information about its carotenoid composition and distribution. The carotenoid profiles including concentration, composition, molecular forms (free or esterified) and configuration (geometrical and optical isomers) of raw and dried T. curvirostris (Stimpson, 1860) were qualitatively and quantitatively assessed. In the raw shrimp, astaxanthin and β-carotene were the two dominant carotenoids, which contributed 75.18%–88.86% and 2.86%–16.83% of the total carotenoid content. Traces of echinenone, canthaxanthin and astacene were also detected. The carotenoid content in the waste (80.28 mg/kg dry weight) was nearly two-fold higher than that in the meat (49.69 mg/kg dry weight). Of the total astaxanthin in these shrimp, 85.18%–90.59% was esterified. All- trans astaxanthin was the predominant geometrical isomer followed by 13- cis , 9- cis , di- cis and 15- cis isomers. A mix of three stereoisomers was found in all parts and the percentages of meso (3 S , 3’ R ) and (3 S , 3’ S ) forms were significantly higher than the (3 R , 3’ R ) isomer. Compared to the carotenoid content of the raw shrimp, only 26.17 mg/kg remained in the dried shrimp. Nearly half of the carotenoids were lost during the drying process. substantial hydrolysis and isomerization also occurred.

关键词： Trachysalambria curvirostris carotenoids astaxanthin dried shrimp