期刊文献+
共找到93篇文章
< 1 2 5 >
每页显示 20 50 100
Deep learning model based on PET/CT and combination with Cox proportional hazard model for predicting progression of lung invasive adenocarcinoma after surgery
1
作者 LI Yingci WU Dongbo GONG Feifei 《中国医学影像技术》 CSCD 北大核心 2024年第8期1194-1198,共5页
Objective To observe the efficacy of deep learning(DL)model based on PET/CT and its combination with Cox proportional hazard model for predicting progressive disease(PD)of lung invasive adenocarcinoma within 5 years a... Objective To observe the efficacy of deep learning(DL)model based on PET/CT and its combination with Cox proportional hazard model for predicting progressive disease(PD)of lung invasive adenocarcinoma within 5 years after surgery.Methods The clinical,PET/CT and 5-year follow-up data of 250 patients with lung invasive adenocarcinoma were retrospectively analyzed.According to PD or not,the patients were divided into the PD group(n=71)and non-PD group(n=179).The basic data and PET/CT findings were compared between groups,among which the quantitative variables being significant different between groups were transformed to categorical variables using receiver operating characteristic(ROC)curve and corresponding cut-off value.Multivariant Cox proportional hazard model was used to select independent predicting factors of PD of lung invasive adenocarcinoma within 5 years after surgery.The patients were divided into training,validation and test sets at the ratio of 6∶2∶2,and PET/CT data in training set and validation set were used to train model and tuning parameters to build the PET/CT DL model,and the combination model was built in serial connection of DL model and the predictive factors.In test set,the efficacy of each model for predicting PD of lung invasive adenocarcinoma within 5 years after surgery was assessed and compared using the area under the curve(AUC).Results Patients'gender and smoking status,as well as the long diameter,SUV max and SUV mean of lesions measured on PET images,the long diameter,short diameter and type of lesions showed on CT were statistically different between groups(all P<0.05).Smoking(HR=1.787[1.053,3.031],P=0.031)and lesion SUV max>4.15(HR=5.249[1.062,25.945],P=0.042)were both predictors of PD of lung invasive adenocarcinoma within 5 years after surgery.In test set,the AUC of PET/CT DL model for predicting PD was 0.847,of the combination model was 0.890,of the latter was higher than of the former(P=0.036).Conclusion DL model based on PET/CT had high efficacy for predicting PD of lung invasive adenocarcinoma within 5 years after surgery.Combining with Cox proportional hazard model could further improve its predicting efficacy. 展开更多
关键词 adenocarcinoma of lung positron-emission tomography and computed tomography deep learning disease progression
下载PDF
Optimization and Testing for PCR System of Rice by Orthogonal Design 被引量:8
2
作者 程芳艳 李春光 +5 位作者 刘永巍 孟巧霞 张景龙 宋冬明 刘华招 孟昭河 《Agricultural Science & Technology》 CAS 2010年第2期61-64,共4页
[Objective] This study was to screen the economic or stable PCR system of rice and detect the generality of the selected system in different molecular markers based on PCR.[Method] With DNA extracted from rice leaves ... [Objective] This study was to screen the economic or stable PCR system of rice and detect the generality of the selected system in different molecular markers based on PCR.[Method] With DNA extracted from rice leaves by CTAB method as the template,PCR system was optimized by L16(45)orthogonal design.[Result] Clear bands were amplified from 16 different combinations,but the amplification effects and yields had difference.The most economic and applicable system was as follows:20 ng DNA template,150 μmol/L dNT... 展开更多
关键词 RICE PCR system optimization Orthogonal design Dominant molecular markers testing
下载PDF
Influence of freezing rate on microstructure and electrochemical properties of Mg-2%Ga alloys 被引量:1
3
作者 冯艳 王日初 彭超群 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第5期1047-1051,共5页
Equilibrium freezing curve of Mg-2%Ga (mass fraction) alloy was calculated by CALPHALD method. Microstructures of the melted Mg-2%Ga alloys solidified by iron and copper moulds, respectively, were investigated using... Equilibrium freezing curve of Mg-2%Ga (mass fraction) alloy was calculated by CALPHALD method. Microstructures of the melted Mg-2%Ga alloys solidified by iron and copper moulds, respectively, were investigated using OM and SEM. Electrochemical properties of the Mg-2%Ga alloys with different freezing rates were measured by galvanostatic, potentiodynamic and electrochemical impedance spectroscopy tests. The results show that solidification by copper mould leads to intergranular MgsGa2 compounds with small size and large number density. Less adsorbent of Mg^+ and oxide corrosion products occur on the surface of the Mg-2%Ga alloys solidified by copper mould, producing lower corrosion current density of 1.8×10^-5 mA/cm^2. In the galvanostatic tests with 100 mA/cm^2 current density, more negative stable potential of-1.604 V exists in the Mg-2%Ga alloys solidified by iron mould due to the lower freezing rate, which leads to smaller inductive and capacity time constants as well as shorter activity time and better electrochemical activity. 展开更多
关键词 Mg-Ga alloy electrode materials electrochemical reaction MICROSTRUCTURE computer simulation
下载PDF
HARDWARE-BASED VOXELIZATION FOR TRUE 3-D DISPLAY 被引量:5
4
作者 谭皓 杨忠 +1 位作者 李玉峰 沈春林 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2006年第1期59-64,共6页
An efficient voxelization algorithm is presented for polygonal models by using the hardware support for the 2 D rasterization algorithm and the GPU programmable function to satisfy the volumetric display system. The v... An efficient voxelization algorithm is presented for polygonal models by using the hardware support for the 2 D rasterization algorithm and the GPU programmable function to satisfy the volumetric display system. The volume is sampled into slices by the rendering hardware and then slices are rasterated into a series of voxels. A composed buffer is used to record encoded voxels of the target volume to reduce the graphic memory requirement. In the algorithm, dynamic vertexes and index buffers are used to improve the voxelization efficiency. Experimental results show that the algorithm is efficient for a true 3-D display system. 展开更多
关键词 computer graphics VOXELIZATION volumetric display mesh model
下载PDF
A meta-analytic review of the approach-avoidance achievement goals and performance relationships in the sport psychology literature 被引量:2
5
作者 Marc Lochbaum Jarrett Gottardy 《Journal of Sport and Health Science》 SCIE 2015年第2期164-173,共10页
Purpose: To summarize the approach-avoidance achievement goal and performance in the sport psychology literature.Methods: A total of 17 published studies, two of which provided two samples, were located. Accepted me... Purpose: To summarize the approach-avoidance achievement goal and performance in the sport psychology literature.Methods: A total of 17 published studies, two of which provided two samples, were located. Accepted meta-analytic procedures were used with Hedges g as the effect size metric. From the 17 studies, 73 effect sizes were calculated.Results: Results based on a random effects model indicated that the performance goal contrast had the largest facilitative impact on performance followed by the mastery and performance approach goals. Both of the avoidance goals performance and mastery had small non-significant and detrimental effects on performance. The homogeneity statistics revealed significant heterogeneity for the approach and avoidance performance goals. Categorical moderator variables were examined for study sex composition(male, female, or mixed), mean age of sample(〈18 years or 18 years), study setting(lab or naturalistic), and nature of performance variable(objective or subjective).Conclusion: The performance goal contrast holds value for sport performance research. Contrary to approach-avoidance predictions, the mastery-approach goal and performance effect size was significant and of equal magnitude as the performance approach goal and performance effect size. Thus, future research should closely test the efficacy of both the mastery- and performance contrasts in impacting performance of sport tasks. Last, the significant effect sizes reported in this review are in stark contrast to contemporary meta-analytic findings in education.Differences in the approach-avoidance goals in sport and education relative to performance should be researched further. 展开更多
关键词 Mastery approach goals Performance approach goals Performance enhancement Performance goal contrast
下载PDF
Advances in small animal mesentery models for in vivo flow cytometry,dynamic microscopy,and drug screening 被引量:2
6
作者 Ekaterina I Galanzha Valery V Tuchin Vladimir P Zharov 《World Journal of Gastroenterology》 SCIE CAS CSCD 2007年第2期192-218,共27页
Using animal mesentery with intravital optical microscopy is a well-established experimental model for studying blood and lymph microcirculation in vivo. Recent advances in cell biology and optical techniques provide ... Using animal mesentery with intravital optical microscopy is a well-established experimental model for studying blood and lymph microcirculation in vivo. Recent advances in cell biology and optical techniques provide the basis for extending this model for new applications, which should generate significantly improved experimental data. This review summarizes the achievements in this specific area, including in vivo label-free blood and lymph photothermal flow cytometry, super-sensitive fluorescence image cytometry, light scattering and speckle flow cytometry, microvessel dynamic microscopy, infrared (IR) angiography, and high-speed imaging of individual cells in fast flow. The capabilities of these techniques, using the rat mesentery model, were demonstrated in various studies; e.g., real-time quantitative detection of circulating and migrating individual blood and cancer cells, studies on vascular dynamics with a focus on lymphatics under normal conditions and under different interventions (e.g. lasers, drugs, nicotine), assessment of lymphatic disturbances from experimental lymphedema, monitoring cell traffic between blood and lymph systems, and high-speed imaging of cell transient deformability in flow. In particular, the obtained results demonstrated that individual cell transportation in living organisms depends on cell type (e.g., normal blood or leukemic cells), the cell’s functional state (e.g., live, apoptotic, or necrotic), and the functional status of the organism. Possible future applications, including in vivo early diagnosis and prevention of disease, monitoring immune response and apoptosis, chemo- and radio-sensitivity tests, and drug screening, are also discussed. 展开更多
关键词 Lymph microcirculation Transmission digital microscopy Rat mesentery Flow cytometry Photothermal technique
下载PDF
E-Bayesian Estimation of the Products Reliability when Testing Reveals no Failure 被引量:1
7
作者 韩明 《Chinese Quarterly Journal of Mathematics》 CSCD 2009年第3期407-414,共8页
This paper develops a new method, named E-Bayesian estimation method, to estimate the reliability parameters. The E-Bayesian estimation method of the reliability are derived for the zero-failure data from the product ... This paper develops a new method, named E-Bayesian estimation method, to estimate the reliability parameters. The E-Bayesian estimation method of the reliability are derived for the zero-failure data from the product with Binomial distribution. Firstly, for the product reliability, the definitions of E-Bayesian estimation were given, and on the base, expressions of the E-Bayesian estimation and hierarchical Bayesian estimation of the products reliability was given. Secondly, discuss properties of the E-Bayesian estimation. Finally, the new method is applied to a real zero-failure data set, and as can be seen, it is both efficient and easy to operate. 展开更多
关键词 RELIABILITY zero-failure data E-Bayesian estimation hierarchical Bayesian estimation
下载PDF
The Impacts of the Interannual Variability of Vegetation on the Interannual Variability of Global Evapotranspiration: A Modeling Study 被引量:1
8
作者 CHEN Hao ZENG Xiao-Dong 《Atmospheric and Oceanic Science Letters》 2012年第3期225-230,共6页
The impact of the interannual variability (IAV) of vegetation on the IAV of evapotranspiration is investigated with the Community Land Model (CLM3.0) and modified Dynamic Global Vegetation Model (DGVM). Two sets of 50... The impact of the interannual variability (IAV) of vegetation on the IAV of evapotranspiration is investigated with the Community Land Model (CLM3.0) and modified Dynamic Global Vegetation Model (DGVM). Two sets of 50-year off-line simulations are used in this study. The simulations begin with the same initial surface-water and heat states and are driven by the same atmospheric forcing data. The vegetation exhibits interannual variability in one simulation but not in the other simulation. However, the climatological means for the vegetation are the same. The IAV of the 50-year annual total evapotranspiration and its three partitions (ground evaporation, canopy evaporation, and transpiration) are analyzed. The global distribution of the evapotranspiration IAV and the statistics of evapotranspiration and its components in different ecosystems show that the IAV of ground evaporation is generally large in areas dominated by grass and deciduous trees, whereas the IAV of canopy evaporation and transpiration is large in areas dominated by bare soil and shrubs. For ground evaporation, canopy evaporation, and transpiration, the changes in IAV are larger than the mean state over most grasslands and shrublands. The study of two sites with the same IAV in the leaf area index (LAI) shows that the component with the smaller contribution to the total evapotranspiration is more sensitive to the IAV of vegetation. The IAV of the three components of evapotranspiration increases with the IAV of the fractional coverage (FC) and the LAI. The ground evaporation IAV shows the greatest increase, whereas the canopy evaporation shows the smallest increase. 展开更多
关键词 interannual variability EVAPOTRANSPIRATION ground evaporation canopy evaporation TRANSPIRATION
下载PDF
An Explicit Solution for Thermal Calculation and Synthesis of Super-structure Heat Exchanger Networks 被引量:2
9
作者 陈德珍 杨杉杉 +2 位作者 罗行 温卿云 马虎根 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2007年第2期296-301,共6页
For the optimal design of a heat exchanger network,the inlet and outlet stream temperatures of each heat exchanger in the network should be known.An explicit analytical solution of stream temperatures of an arbi-trary... For the optimal design of a heat exchanger network,the inlet and outlet stream temperatures of each heat exchanger in the network should be known.An explicit analytical solution of stream temperatures of an arbi-trary connected heat exchanger network was introduced,which is suitable for the thermal calculation of heat ex-changer networks.For the heat exchanger network synthesis,this solution was further developed and coupled with the stage-wise superstructure heat exchanger networks.The new calculation procedure reduced the computer mem-ory requirement dramatically.On the basis of this solution,a mathematical model for synthesis of heat exchanger networks with genetic algorithm was formulated,which is always feasible and no iteration is needed.Two examples were calculated with the proposed approach and better results were obtained. 展开更多
关键词 heat recovery system stage-wise superstructure heat exchanger network synthesis genetic algorithm OPTIMIZATION
下载PDF
Predictive value of ^(18)F-fluorodeoxyglucose PET/CT for transarterial chemolipiodolization of hepatocellular carcinoma 被引量:8
10
作者 Myeong Jun Song Si Hyun Bae +7 位作者 Ie Ryung Yoo Chung-Hwa Park Jeong Won Jang Ho Jong Chun Byung Gil Choi Hae Giu Lee Jong Young Choi Seung Kew Yoon 《World Journal of Gastroenterology》 SCIE CAS CSCD 2012年第25期3215-3222,共8页
AIM: To investigate the correlation of 18F-fluorodeoxy- glucose (18F-FDG) positron emission tomography (PET) with clinical features and the prediction of treatment response. METHODS: A total of 83 hepatocellular... AIM: To investigate the correlation of 18F-fluorodeoxy- glucose (18F-FDG) positron emission tomography (PET) with clinical features and the prediction of treatment response. METHODS: A total of 83 hepatocellular carcinoma (HCC) patients undergoing 18F-FDG PET before transar- terial chemolipiodolization with systemic chemo-infusion between October, 2006 and May, 2009 were retrospec-tively enrolled. The patients included 68 men and 15 women (mean age, 60 ~ 10.7 years). The effect of 18F- FDG-monitored PET uptake on clinical features and on the evaluated treatment response was ascertained with modified Response Evaluation Criteria in Solid Tumors. The PET parameters of maximal standardized uptake value of the tumor (Tsuvmax), the ratio of the tumor maximal standardized uptake value (SUV) to the liver maximal SUV (Tsuvmax/Lsuwax) and the ratio of tumor maximal SUV to the liver mean SUV (msuvmax/LSUVrnean) were tested as predictive factors. RESULTS: Among the 3 SUV parameters, the TSUV- =maxdLsuvmean ratio (cutoff value of 1.90) was significantly associated with tumor burden including tumor size, tu- mor number, α-fetoprotein levels and tumor stage (P 〈 0.001, P = 0.008, P = 0.011, P 〈 0.001, respectively). The objective response rates in patients with a high SUV ratio (≥ 1.90) were significantly better than those with a low SUV ratio (〈 1.90) (P = 0.020). The overall survival rates of patients exhibiting a low Tsuvmax/Lsu- Vmean ratio (〈 1.90) and those with a high SUV ratio (≥1.90) was 38.2 and 10.3 mo, respectively (P 〈 0.01). However, the time to progression showed no significant difference between the groups (P = 0.15). CONCLUSION: 18F-FDG PET can be an important predictor of HCC treatment. In particular, the Tsuvmax/ Lsuwean ratio (cutoff value of 1.90) can provide useful information in treatment prognosis for HCC patients treated with Iocoregional therapy. 展开更多
关键词 18F-fluorodeoxyglucose positron emissiontomography Transarterial chemolipiodolization withsystemic chemo-infusion Treatment response Predic-tive factor Overall survival
下载PDF
Science Letters:Mask synthesis and verification based on geometric model for surface micro-machined MEMS 被引量:1
11
作者 李建华 刘玉生 高曙明 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2005年第9期1007-1010,共4页
Traditional MEMS (microelectromechanical system) design methodology is not a structured method and has become an obstacle for MEMS creative design. In this paper, a novel method of mask synthesis and verification fo... Traditional MEMS (microelectromechanical system) design methodology is not a structured method and has become an obstacle for MEMS creative design. In this paper, a novel method of mask synthesis and verification for surface micro-machined MEMS is proposed, which is based on the geometric model of a MEMS device. The emphasis is focused on synthesizing the masks at the basis of the layer model generated from the geometric model of the MEMS device. The method is comprised of several steps: the correction of the layer model, the generation of initial masks and final masks including multi-layer etch masks, and mask simulation. Finally some test resuhs are given. 展开更多
关键词 MEMS CAD Geometric model Layer model Mask synthesis Surface micromachining
下载PDF
Which Endpoints Can Be Reliably Assessed in Semi-field Pollinator Species Testing without Estimating False Positive or False Negative? MDD’s and Replicates Issue
12
作者 Marco Pompeo Candolfi Holger Bargen +4 位作者 Sigrun Bocksch Olaf Klein Marco Kleinhenz Silvio Knaebe Bronislawa Szczesniak 《Journal of Agricultural Science and Technology(A)》 2018年第3期142-161,共20页
Statistical power, number of replicates and experiment complexity of semi-field and field studies on Apis and non-Apis bee species has become a major issue after publication of the draft European Food Safety Authori... Statistical power, number of replicates and experiment complexity of semi-field and field studies on Apis and non-Apis bee species has become a major issue after publication of the draft European Food Safety Authority (EFSA) Guidance on risk assessment of plant protection products (PPP) on bees (Apis mellifera, Bombus spp. and solitary bees). According to this guidance document, field studies have to be designed to be able to detect significance differences as low as 7% for certain endpoints such as reduction in colony size. This will require an immense number of replicates which is obviously not feasible. In the present study, key endpoints such as mortality, termination rate and number of brood cells in honeybee studies, cocoon production and flight activity in solitary bee studies and number of gynes in bumble bee studies (just to mention some of the endpoints considered) in semi-field studies were analyzed, with Apis mellifera, Bombus terrestris and Osmia bicornis during the past five years (2013-2017). The results indicate huge differences in the percentage minimal detectable differences (%MDDs) (MDD expressed as median of control value of the endpoint in percent) depending on endpoint and species tested. For honeybee semi-field studies, the lowest %MDDs recorded were between 10% and 15% for the endpoints foraging, number of brood cells and colony strength. The highest %MDDs were observed for the endpoint termination rate, with a %MDD of almost 50%. For the endpoints in bumble bee semi-field studies the %MDDs varied between 17% for bumble bee colony weight and 53% for average mortality during the exposure period in the tunnel. The %MDD for the number of gynes (young queens) was slightly below 25%. For the semi-field solitary bee test system, the %MDDs for the measured endpoints seem to be lower than those for the other two species tested. The %MDDs for the endpoints hatching of offspring, nest occupation and number of cocoons were 8%, 13% and 14%, respectively. Most of the %MDDs were between 10% and 30% indicating clearly that the currently performed experimental design for the semi-field pollinator studies allowed to determine relatively small effects on key study endpoints. The analysis indicated that for all the three bee species tested, the semi-field test design detected low %MDDs for most of the endpoints. It was also observed that detectable differences between the control and PPP treatments were much lower in semi-field test designs than in field studies with these bee species. The “perfect sample size” really does not exist but test design and statistical analysis can be adapted to lower the %MDDs. Measured and simulated (according to Student’s t-test-distribution) data and results showed that statistical evaluations parameter selection (e.g., alpha value), data transformation (log10) and the number of replicates had a direct effect on the ability of the test design to detect lower or higher %MDD values. It could show that a change of alpha value from 0.05 to 0.1, increases the ability of the studies to detect lower %MDDs. For most of the measured endpoints, increasing the number of replicates e.g., from four to eight, improved the power of the test design by decreasing the %MDD. The reduction magnitude of the %MDD is dependent on the endpoint and selection of statistical parameters such as the alpha value. Parameters that display effects at a biologically relevant scale will be a better indicator for effects than parameters that are able to detect minor differences that are not biologically relevant. 展开更多
关键词 Apis mellifera Bombus terrestris Osmia bicornis OECD75 minimal detectable difference (MDD) statistical power
下载PDF
Fractal analysis of thermal conduction of loose coal 被引量:2
13
作者 WANG Yijiang ZHOU Guoqing +1 位作者 WEI Yazhi ZHOU Yang 《Mining Science and Technology》 EI CAS 2010年第6期831-834,838,共5页
For deep mining engineering, heat transfer of coal mass is a vital factor in the thermal environment of coal mines. In order to study the thermal conduction mechanism, we obtained gray images of coal mass microstructu... For deep mining engineering, heat transfer of coal mass is a vital factor in the thermal environment of coal mines. In order to study the thermal conduction mechanism, we obtained gray images of coal mass microstructure by scanning samples with a digital microscope. With the use of Matlab, these gray images were transformed into binary images, which were then transformed into a corresponding matrix consisting only of the values 0 and 1. According to the calculation method of box-counting dimension, we calculated the fractal dimension of the loose coal to be approximately 1.86. The thermal conductivity expressions of loose coal were derived based on the simulation method of thermal resistance. We calculated the thermal conductivity of loose coal by using a fractal model and compared the calculated values with our experimental data. The results show that the test data show an encourag-ing agreement with the calculated values. Hence fractal theory is a feasible method for studying thermal conductivity of loose coal. 展开更多
关键词 loose coal thermal conductivity fractal theory box-counting dimension
下载PDF
Smooth interpolation on homogeneous matrix groups for computer animation 被引量:1
14
作者 LI Jun HAO Peng-wei 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第7期1168-1177,共10页
Homogeneous matrices are widely used to represent geometric transformations in computer graphics, with interpo- lation between those matrices being of high interest for computer animation. Many approaches have been pr... Homogeneous matrices are widely used to represent geometric transformations in computer graphics, with interpo- lation between those matrices being of high interest for computer animation. Many approaches have been proposed to address this problem, including computing matrix curves from curves in Euclidean space by registration, representing one-parameter curves on manifold by rational representations, changing subdivisional methods generating curves in Euclidean space to corresponding methods working for matrix curve generation, and variational methods. In this paper, we propose a scheme to generate rational one-parameter matrix curves based on exponential map for interpolation, and demonstrate how to obtain higher smoothness from existing curves. We also give an iterative technique for rapid computing of these curves. We take the computation as solving an ordinary differential equation on manifold numerically by a generalized Euler method. Furthermore, we give this algorithm’s bound of the error and prove that the bound is proportional to the shift length when the shift length is sufficiently small. Compared to direct computation of the matrix functions, our Euler solution is faster. 展开更多
关键词 Computer animation Spline and piecewise polynomial approximation
下载PDF
Major and Minor Harmonic Keys: The Discrepancy in Chord Classification Under a Computational Tonality Analytical Method
15
作者 Miroslaw Majchrzak 《Journal of Literature and Art Studies》 2013年第6期381-390,共10页
Basing upon the tonality analytic method, the present paper aims at: (1) Drawing attention to the subordination of the minor key vs. the major key in the chord classification, using the same methodology; and (2) ... Basing upon the tonality analytic method, the present paper aims at: (1) Drawing attention to the subordination of the minor key vs. the major key in the chord classification, using the same methodology; and (2) Showing the differences for the major key and the minor (harmonic) key in the classification of chords, as an aspect of importance for interpreting a piece's tonal structure diagram. The relations between chords appearing in the major and minor (harmonic) key will be shown by applying the comparisons of: (1) third-based chords; and (2) degrees in the C major and A minor keys, on which the same diatonic chords appear. 展开更多
关键词 TONALITY MODES classification of diatonic chords methodology
下载PDF
Microstructures and mechanical properties of Ti−Al−V−Nb alloys with cluster formula manufactured by laser additive manufacturing 被引量:10
16
作者 Tian-yu LIU Xiao-hua MIN +2 位作者 Shuang ZHANG Cun-shan WANG Chuang DONG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2021年第10期3012-3023,共12页
Ti−Al−V−Nb alloys with the cluster formula,12[Al−Ti_(12)](AlTi_(2))+5[Al−Ti1_(4)](V,Nb)2Ti,were designed by replacing V with Nb based on the Ti−6Al−4V alloy.Single-track cladding layers and bulk samples of the alloys ... Ti−Al−V−Nb alloys with the cluster formula,12[Al−Ti_(12)](AlTi_(2))+5[Al−Ti1_(4)](V,Nb)2Ti,were designed by replacing V with Nb based on the Ti−6Al−4V alloy.Single-track cladding layers and bulk samples of the alloys with Nb contents ranging from 0 to 6.96 wt.%were prepared by laser additive manufacturing to examine their formability,microstructure,and mechanical properties.For single-track cladding layers,the addition of Nb increased the surface roughness slightly and decreased the molten pool height to improve its spreadability.The alloy,Ti−5.96Al−1.94V−3.54Nb(wt.%),exhibited better geometrical accuracy than the other alloys because its molten pool height was consistent with the spread layer thickness of the powder.The microstructures of the bulk samples contained similar columnar β-phase grains,regardless of Nb content.These grains grew epitaxially from the Ti substrate along the deposition direction,with basket-weaveα-phase laths within the columnar grains.Theα-phase size increased with increasing Nb contents,but its uniformity decreased.Along the deposition direction,the Vickers hardness increased from the substrate to the surface.The Ti−5.96Al−1.94V−3.54Nb alloy exhibited the highest Vickers hardness regardless of deposition position because of the optimal matching relationship between theα-phase size and its content among the designed alloys. 展开更多
关键词 Ti−Al−V−Nb alloy composition design laser additive manufacturing microstructure mechanical properties
下载PDF
EFFECTS OF SLEEP DEPRIVATION ON WHOLE NIGHT POLYSOMNOGRAPHY IN HEALTHY YOUNG MEN
17
作者 肖泽萍 陈兴时 +10 位作者 王继军 张明岛 王红星 胡珍玉 路英智 张载福 甘景梨 楼翡璎 陈冲 张天宏 范青 《Journal of Shanghai Second Medical University(Foreign Language Edition)》 2009年第2期77-80,共4页
Objective To assess the effects of sleep deprivation (SD) on the whole night polysomnography (PSG) in healthy young men. Methods The whole night PSG was recorded by using Neurofax-1518K (Nihon Kohden, Japan) system be... Objective To assess the effects of sleep deprivation (SD) on the whole night polysomnography (PSG) in healthy young men. Methods The whole night PSG was recorded by using Neurofax-1518K (Nihon Kohden, Japan) system before and after 38 h of SD among 15 healthy male subjects. Results Compared with PSG before SD, post-SD PSG showed significantly shortened sleep latency (before SD: 19.7±9.3, after SD: 5.6±7.3, P<0.05), decreased stage 1 (S1) non-rapid eye movement (NREM) sleep [before SD: (9.2±1.9)%, after SD: (4.0±1.4)%, P<0.05], and increased stage 4 (S4) NREM sleep [before SD: (10.3±3.7)%, after SD: (26.2±4.3)%, P<0.01]. Conclusion During post-SD sleep, the proportion of S4 NREM sleep was increased as compensation in healthy male. In addition, SD was proved to affect electrophysiological brain activities in normal people. 展开更多
关键词 sleep deprivation polysomnography
下载PDF
Microstructure and properties of Ti64.51Fe26.40Zr5.86Sn2.93Y0.30 biomedical alloy fabricated by laser additive manufacturing 被引量:11
18
作者 Li-ying HAN Cun-shan WANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2020年第12期3274-3286,共13页
From the perspective of biomechanics and forming technology,Ti−Fe−Zr−Sn−Y eutectic alloy was designed using a“cluster-plus-glue-atom”model,and then the alloy was prepared by laser additive manufacturing(LAM)on pure ... From the perspective of biomechanics and forming technology,Ti−Fe−Zr−Sn−Y eutectic alloy was designed using a“cluster-plus-glue-atom”model,and then the alloy was prepared by laser additive manufacturing(LAM)on pure titanium substrate.The mechanical properties of the alloy were evaluated using micro-hardness and compression tester,and the elastic modulus was measured by nanoindenter.The results show that the alloy exhibits a high hardness of HV(788±10),a high strength of 2229 MPa,a failure strain of 14%,and a low elastic modulus of 87.5 GPa.The alloy also has good tribological,chemical,forming,and biological properties.The comprehensive performances of the Ti64.51Fe26.40Zr5.86Sn2.93Y0.30 alloy are superior to those of the Ti70.5Fe29.5 eutectic alloy and commercial Ti−6Al−4V alloy.All the above-mentioned qualities make the alloy a promising candidate as LAM biomaterial. 展开更多
关键词 laser additive manufacturing composition design biomedical titanium alloy microstructure PROPERTY
下载PDF
Electronic Chart Display and Information System 被引量:3
19
作者 WAN Xiaoxia GAN Chaohua 《Geo-Spatial Information Science》 2002年第1期7-11,21,共6页
This paper introduces the most advanced form of electronic chart display and information systems (ECDIS) which complies with the Performance Standards for ECDIS established by the International Maritime Organization (... This paper introduces the most advanced form of electronic chart display and information systems (ECDIS) which complies with the Performance Standards for ECDIS established by the International Maritime Organization (IMO) and the International Hydrographic Organization (IHO).It also describes the key features and the important functions of ECDIS.Then the future development of ECDIS in marine is discussed. 展开更多
关键词 ECDIS ECS DISPLAY key features performance standards
下载PDF
Information Fusion Methods in Computer Pan-vision System
20
作者 车录锋 Zhou Xiaojun +1 位作者 Xu Zhinong Cheng Yaodong 《High Technology Letters》 EI CAS 2002年第2期92-96,共5页
Aiming at concrete tasks of information fusion in computer pan vision (CPV) system, information fusion methods are studied thoroughly. Some research progresses are presented. Recognizing of vision testing object is re... Aiming at concrete tasks of information fusion in computer pan vision (CPV) system, information fusion methods are studied thoroughly. Some research progresses are presented. Recognizing of vision testing object is realized by fusing vision information and non vision auxiliary information, which contain recognition of material defects, intelligent robot’s autonomous recognition for parts and computer to defect image understanding and recognition automatically. 展开更多
关键词 computer vision information fusion matter element image understanding
下载PDF
上一页 1 2 5 下一页 到第
使用帮助 返回顶部