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The Effects of Dwarfing Genes (Rht-B1b, Rht-D1b, and Rht8) with Different Sensitivity to GA_3 on the Coleoptile Length and Plant Height of Wheat 被引量:14
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作者 TANG Na JIANG Ying +1 位作者 HE Bei-ru HU Yin-gang 《Agricultural Sciences in China》 CAS CSCD 2009年第9期1028-1038,共11页
Understanding the effects of wheat dwarfing genes on the coleoptile length and plant height is crucial for the proper utilization of dwarfing genes in the improvement of wheat yield. Molecular marker analysis combined... Understanding the effects of wheat dwarfing genes on the coleoptile length and plant height is crucial for the proper utilization of dwarfing genes in the improvement of wheat yield. Molecular marker analysis combined with pedigree information were used to classify wheat cultivars widely planted in major wheat growing regions in China into different categories based on the dwarfing genes they carried. The effects of the dwarfing genes with different sensitivity to gibberellins (GA3) on the coleoptile length and plant height were analyzed. Screening of 129 cultivars by molecular marker analysis revealed that 58 genotypes of wheat contained the dwarfing gene Rht-B1b, 24 genotypes of wheat contained Rht-D1b gene and 73 genotypes of wheat possessed Rht8 gene. In addition, among these 129 cultivars, 35 genotypes of wheat cultivars contained both Rht-B1b and Rht8 genes and 16 genotypes of wheat cultivars contained both Rht-D1b and Rht8 genes. Wheat cultivars with the dwarfing genes Rht-B1b or Rht-D1b were insensitive to GA3, while the cultivars with the dwarfing gene Rht8 were sensitive to GA3. Most of the wheat genotypes containing combination of Rht8 gene with either Rht-B1b or Rht-D1b gene were insensitive to GA3. The plant height was reduced by 24.6, 30.4, 28.2, and 32.2%, respectively, for the wheat cultivars containing Rht-B1b, Rht-D1b, Rht-B1b + Rht8, and Rht-D1b + Rht8 genes. The plant height was reduced by 14.3% for the wheat cultivar containing GA3-sensitive gene Rht8. The coleoptile length was shortened by 25.4, 31.3, 28.4 and 31.3%, respectively, in the wheat cultivars containing Rht-B1b, Rht-D1b, Rht-B1b +Rht8 and Rht-D1b + Rht8 genes, while the coleoptile length was shortened only by 6.2% for the wheat cultivar containing Rht8 gene. We conclude that GA3-insensitive dwarfing genes (Rht-B1b and Rht-D1b) are not suitable for the wheat improvement in dryland because these two genes have effect on reducing both plant height and coleoptile length. In contrast, GA3- sensitive dwarfing gene (Rht8) is a relatively ideal candidate for the wheat improvement since it significantly reduces the plant height of wheat, but has less effect on the coleoptile length. 展开更多
关键词 bread wheat dwarfing genes Rht-B1b Rht-D1b Rht8 coleoptile length plant height
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Finite element analysis on the collapse of infill walls with holes and different length-to-height ratios
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作者 周晓方 叶燕华 +1 位作者 SUN Rui YIN Wan-qing 《Journal of Chongqing University》 CAS 2013年第4期155-162,共8页
Wenchuan earthquake damage survey displayed the major structures of buildings suffered only small damages,but it was common that infill walls suffered heavy damages or even collapse. To study the failure forms and col... Wenchuan earthquake damage survey displayed the major structures of buildings suffered only small damages,but it was common that infill walls suffered heavy damages or even collapse. To study the failure forms and collapse mechanism of infill walls in an earthquake,the influence of opening or length-to-height ratio on shake-resisting capability of filling walls was analyzed,and measures to improve the anti-collapse ability of infill walls were put forwaed. The numerical simulations on collapse process in earthquake were carried out by using ABAQUS software. We used 5 single story and single span models. It is revealed that the rigidity and compressive capacity of infill walls are reduced because of the infill walls with holes and the increases of length-to-height ratios. Adding constructional columns and horizontal beams can ensure structural integrity and improve the anti-collapse ability of the wall. 展开更多
关键词 finite element analysis COLLAPSE length-height ratio RIGIDITY
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Nonlinear mixed-effects height to crown base and crown length dynamic models using the branch mortality technique for a Korean larch( Larix olgensis ) plantations in northeast China 被引量:8
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作者 Weiwei Jia Dongsheng Chen 《Journal of Forestry Research》 SCIE CAS CSCD 2019年第6期2095-2109,共15页
Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and... Korean larch(Larix olgensis)is one of the main tree species for aff orestation and timber production in northeast China.However,its timber quality and growth ability are largely infl uenced by crown size,structure and shape.The majority of crown models are static models based on tree size and stand characteristics from temporary sample plots,but crown dynamic models has seldom been constructed.Therefore,this study aimed to develop height to crown base(HCB)and crown length(CL)dynamic models using the branch mortality technique for a Korean larch plantation.The nonlinear mixed-eff ects model with random eff ects,variance functions and correlation structures,was used to build HCB and CL dynamic models.The data were obtained from 95 sample trees of 19 plots in Meng JiaGang forest farm in Northeast China.The results showed that HCB progressively increases as tree age,tree height growth(HT growth)and diameter at breast height growth(DBH growth).The CL was increased with tree age in 20 years ago,and subsequently stabilized.HT growth,DBH growth stand basal area(BAS)and crown competition factor(CCF)signifi cantly infl uenced HCB and CL.The HCB was positively correlated with BAS,HT growth and DBH growth,but negatively correlated with CCF.The CL was positively correlated with BAS and CCF,but negatively correlated with DBH growth.Model fi tting and validation confi rmed that the mixed-eff ects model considering the stand and tree level random eff ects was accurate and reliable for predicting the HCB and CL dynamics.However,the models involving adding variance functions and time series correlation structure could not completely remove heterogeneity and autocorrelation,and the fi tting precision of the models was reduced.Therefore,from the point of view of application,we should take care to avoid setting up over-complex models.The HCB and CL dynamic models in our study may also be incorporated into stand growth and yield model systems in China. 展开更多
关键词 Larix olgensis plantation height to CROWN BASE CROWN length Branch MORTALITY technique NONLINEAR mixed-eff ects models
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New expressions for the surface roughness length and displacement height in the atmospheric boundary layer
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作者 林建忠 李惠君 张凯 《Chinese Physics B》 SCIE EI CAS CSCD 2007年第7期2033-2039,共7页
An alternative model for the prediction of surface roughness length is developed. In the model a new factor is introduced to compensate for the effects of wake diffusion and interactions between the wake and roughness... An alternative model for the prediction of surface roughness length is developed. In the model a new factor is introduced to compensate for the effects of wake diffusion and interactions between the wake and roughness obstacles. The experiments are carried out by the use of the hot wire anemometry in the simulated atmospheric boundary layer in a wind tunnel. Based on the experimental data, a new expression for the zero-plane displacement height is proposed for the square arrays of roughness elements, which highlights the influence of free-stream speed on the roughness length. It appears that the displacement height increases with the wind speed while the surface roughness length decreases with Reynolds number increasing. It is shown that the calculation results based on the new expressions are in reasonable agreement with the experimental data. 展开更多
关键词 roughness length zero-plane displacement height atmospheric boundary layer free stream speed packing density
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Constitutive Activation OsbZIP62 Improves Plant Height and Yield through Regulating the Expression of Agronomic Traits Related Genes in Rice
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作者 Shiqin Yang Tao Jiang +6 位作者 Peilin Shen Shengjie Ren Zhun Gu Fangjun Feng Yunpeng Peng Wei Wang Kai Xu 《Phyton-International Journal of Experimental Botany》 SCIE 2022年第8期1671-1686,共16页
Plant height is an important morphological trait that affects crop yield.Several genes related to plant height and yield have been reported in rice(Oryza sativa L.),however,the molecular mechanism underlying the regul... Plant height is an important morphological trait that affects crop yield.Several genes related to plant height and yield have been reported in rice(Oryza sativa L.),however,the molecular mechanism underlying the regulation of these traits is still not completely understood.VP64 is widely used as a transcriptional activator to investigate the biological function of genes encoding transcription factors.Here,we identified a novel bZIP transcription factor OsbZIP62 that is involved in modulating agronomic traits in rice.Overexpression of OsbZIP62-VP64(OsbZIP62V)significantly increases the plant height and yield per plant in rice.RNA-seq analysis showed that some plant height and panicle development related genes(i.e.,OsEATB,OsDSS1 and OsGA3ox2)were up-regulated in OsbZIP62V overexpressing rice plants.Besides,OsbZIP62 could also bind to the promoters of several putative target genes.These results suggested that OsbZIP62 plays a role as transcriptional regulator in regulating the expression of genes associated with agronomic traits,and OsbZIP62 fused with VP64 would be useful in crop genetic modification with improved plant architecture and yield. 展开更多
关键词 RICE OsbZIP62 panicle length plant height transcription factor YIELD
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Obtaining accurate measurements of the sea surface height from a GPS buoy 被引量:1
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作者 Wanlin Zhai Jianhua Zhu +5 位作者 Chuntao Chen Wu Zhou Longhao Yan Yufei Zhang Xiaoqi Huang Kai Guo 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2023年第6期78-88,共11页
A dedicated GPS buoy is designed for calibration and validation(Cal/Val)of satellite altimeters since 2014.In order to evaluate the accuracy of the sea surface height(SSH)measured by the GPS buoy,twelve campaigns have... A dedicated GPS buoy is designed for calibration and validation(Cal/Val)of satellite altimeters since 2014.In order to evaluate the accuracy of the sea surface height(SSH)measured by the GPS buoy,twelve campaigns have been done within China sea area between 2014 and 2021.In six of these campaigns,two static Global Navigation Satellite System stations were installed at distances of<1 km and 19 km from the buoy to assess how the baseline length influenced the derived SSH from the buoy solutions.The GPS buoy data was processed using the GAMIT/GLOBK software+TRACK module and CSRS-PPP tool to achieve the SSH.The SSH was compared with conventionally tide gauge(TG)data to evaluate the accuracy of the buoy with the standard deviation of the height element.The results showed that the difference in the standard deviation of the SSH from the buoy and the TG was less than 16 mm.The SSHs processed with different ephemeris(Ultra-Rapid,Rapid,Final)were not significantly different.When the baseline length was 19 km,the SSH solution of the GPS buoy performed well,with standard bias of less than 26 mm between the heights measured by the buoy and TG,meaning that the buoy could be used for Cal/Val of altimeters.The bias between the Canadian Spatial Reference System-precise point positioning tool and the TRACK varied a lot,and some of them were over 130 mm.This deemed too high to be useful for Cal/Val of satellite altimeters.Moreover,the GPS buoy solutions processed by GAMIT/GLOBK software+TRACK module were used for in-orbit Cal/Val of HY-2B/C satellites in ten campaigns.The SSH and significant wave height of the altimeters showed good agreements with the GPS buoy solutions. 展开更多
关键词 GPS buoy sea surface height baseline length precise point positioning satellite altimeter HY-2
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Reconstructing the size of individual trees using log data from cut-to-length harvesters in Pinus radiata plantations: a case study in NSW, Australia 被引量:4
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作者 Kuan Lu Huiquan Bi +2 位作者 Duncan Watt Martin Strandgard Yun Li 《Journal of Forestry Research》 SCIE CAS CSCD 2018年第1期13-33,共21页
With their widespread utilization, cut-to-length harvesters have become a major source of ‘‘big data’’ for forest management as they constantly capture, and provide a daily flow of, information on log production a... With their widespread utilization, cut-to-length harvesters have become a major source of ‘‘big data’’ for forest management as they constantly capture, and provide a daily flow of, information on log production and assortment over large operational areas. Harvester data afford the calculation of the total log length between the stump and the last cut but not the total height of trees. They also contain the length and end diameters of individual logs but not always the diameter at breast height overbark(DBHOB) of harvested stems largely because of time lapse, operating and processing issues and other system deficiencies. Even when DBHOB is extracted from harvester data, errors and/or bias of the machine measurements due to the variation in the stump height of harvested stems from that specified for the harvester head prior to harvesting and diameter measurement errors may need to be corrected. This study developed(1) a system of equations for estimating DBHOB of trees from diameter overbark(DOB) measured by a harvester head at any height up to 3 m above ground level and(2) an equation to predict the total height of harvested stems in P. radiata plantations from harvester data. To generate the data required for this purpose, cut-to-length simulations of more than 3000 trees with detailed taper measurements were carried out in the computer using the cutting patterns extracted from the harvester data and stump height survey data from clearfall operations. The equation predicted total tree height from DBHOB, total log length and the small end diameter of the top log. Prediction accuracy for total tree height was evaluated both globally over the entire data space and locally within partitioned subspaces through benchmarking statistics. These statistics were better than that of the conventional height-diameter equations for P. radiata found in the literature, even when they incorporated stand age and the average height and diameter of dominant trees in the stand as predictors. So this equation when used with harvester data would outperform the conventional equations in tree height prediction. Tree and stand reconstructions of the harvested forest is the necessary first step to provide the essential link of harvester data to conventional inventory, remote sensing imagery and Li DAR data. The equations developed in this study will provide such a linkage for the most effective combined use of harvester data in predicting the attributes of individual trees, stands and forests, and product recovery for the management and planning of P. radiata plantations in New South Wales, Australia. 展开更多
关键词 Cut-to-length simulations Harvesters Big data Diameter and height estimation
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Study of the Effect of Changes on the Technological and Physical-Mechanical Properties of Knitting in a New Structure 被引量:1
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作者 Shahboz Shokirjonugli Shogofurov Iroda Ibrohimovna Kamalova Kurbonali Madaminovich Xolikov 《Engineering(科研)》 2021年第6期287-299,共13页
In this article, we compared four types of knitted fabrics with high two-ply shape retention. Experimental samples of a two-layer knitted fabric have been developed and graphic symbols have been applied on a flat-need... In this article, we compared four types of knitted fabrics with high two-ply shape retention. Experimental samples of a two-layer knitted fabric have been developed and graphic symbols have been applied on a flat-needle weaving machine of the 12th class LONG-XING SM 252 (China). 展开更多
关键词 KNITWEAR Double Knit HOOP YARN Flat Dimensional Lightness Hoop height Surface Density Pattern Density Hoop Strip length POLYACRYLONITRILE
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Effect of Dominant Semi-Dwarf Gene on Plant Height and Its Related Traits and Sensitivity to Gibberellic Acid in Rice
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作者 LIU Bin-mei CHENG Can +4 位作者 Wu Yue-jin TONG Ji-ping WU Jin-hua ZHANG Ying YUAN Qin 《Rice science》 SCIE 2006年第3期179-184,共6页
Six pairs of tall and dwarf near-isogenic lines derived from a dominant semi-dwarf mutant (Y98149) were selected to study height expression and sensitivity to gibberellic acid (GA3). The lengths of the 4-5th inter... Six pairs of tall and dwarf near-isogenic lines derived from a dominant semi-dwarf mutant (Y98149) were selected to study height expression and sensitivity to gibberellic acid (GA3). The lengths of the 4-5th internode, the 3rd, 2nd, 1st internodes from the top and the panicle length in the six dwarf near isogenic lines were 97.2%, 53.3%, 65.1%, 61.9% and 94.7% of those in the six tall ones, respectively, indicating that the dominant semi-dwarfing gene significantly inhibited the internode elongation. Moreover, Y98149 (mutant type) was more sensitive to GA3 than Y98148 (wild type), and had a lower GA3 concentration in plant, about 78% of Y98148. 展开更多
关键词 semi-dwarf gene near isogenic lines plant height internode length sensitivity gibberellic acid RICE
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Evaluation of Relationship between the Geometry of Crown and Radial Force in a Polydioxanone Coronary Stent
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作者 杨洁莹 阙志文 +1 位作者 陈南梁 张佩华 《Journal of Donghua University(English Edition)》 EI CAS 2013年第5期389-390,共2页
Polydioxanone(PDS),one of the bioabsorbable materials for coronary stent,is catching eyes of researchers recently. When designing the geometry of the PDS coronary stent,the length and the height of the crown are quite... Polydioxanone(PDS),one of the bioabsorbable materials for coronary stent,is catching eyes of researchers recently. When designing the geometry of the PDS coronary stent,the length and the height of the crown are quite important. However,rarely literatures have discussed the relationship between the two geometry parameters and the radial force of the bioabsorbable coronary stent. Therefore,a current effective tool of finite element method was applied in the evaluation of the relationship. By simulating 4 groups of models,it was obtained that the radial force of the coronary stent would not definitely increase with the rising value of Lcrownfrom 0. 8 mm to 2. 4mm. Meanwhile,Hcrownand radial force of the coronary stent had no linear relationship with each other. 展开更多
关键词 polydioxanone(PDS) CORONARY STENT finite element method the length of the CROWN the height of the CROWN
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Longitudinal Relationship between Axial Length and Height in Chinese Children:Guangzhou Twin Eye Study
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作者 Decai Wang Chen Zhao +2 位作者 Shengsong Huang Wenyong Huang Mingguang He 《Eye Science》 CAS 2015年第1期1-6,12,共7页
Purpose:.To understand the growth model of axial length(AL) and height, and to explore the relationship between the two with the passage of time.Methods:.We followed twins in the Guangzhou Twin Eye Study for five year... Purpose:.To understand the growth model of axial length(AL) and height, and to explore the relationship between the two with the passage of time.Methods:.We followed twins in the Guangzhou Twin Eye Study for five years..The AL of both eyes was measured by partial coherence interferometry, and height was measured by a standard scale during each visit..A multivariate multilevel mixed model was adopted for data analysis.Results:.A total of 1217 children were included in the study.Both AL and height increased, but the rate of growth slowed down with age..The mitigation rate of height growth was-0.34 cm / year;.while that of AL growth was-0.01 mm / year.AL was positively related to height,.with a relevant coefficient of R=0.22(Cov [height intercept, AL intercept] =1.56, 95%CI=1.14 to 1.99). The growth rates of AL and height were also positively related, with a relevant coefficient of R =0.18(Cov [height slope, AL slope] =0.03, 95%CI=0.01 to 0.05).However, taller children had slower rates of height increases,with a relevant coefficient of R=-0.12(Cov[height intercept,height slope]=-1.33,95%CI=-2.25 to-0.42); but had faster AL growth,.with a relevant coefficient of R =(Cov [height intercept, AL slope] =0.02, 95%CI=-0.05 to 0.08, R=0.02).AL and its growth rate were positively related to each other,with a relevant coefficient of R=(Cov [AL intercept,.AL slope]=0.04, 95%CI=0.03 to 0.05, R=0.3); while the growth rates of AL and height were negatively related to each other, with a relevant coefficient of R=(Cov [AL intercept, height slope]=--0.03 95%CI=-0.16 to 0.1, R=-0.02).Conclusion:.The increase in children's AL is relevant to their height increases..The faster their height increases,.the faster their AL increases. 展开更多
关键词 轴向长度 儿童 科研 广州 相关系数 冠状病毒 拦截高度 中国
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Improving advantages and reducing risks in increasing cyclone height via an apex cone to grasp vortex end 被引量:1
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作者 Ronghua Zhang Jingxuan Yang +2 位作者 Shaoxing Han Xiaogang Hao Guoqing Guan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2023年第2期136-143,共8页
For a cyclone, it is possible to improve separation efficiency and reduce pressure drop by increasing the cyclone height. However, an exceeded height increase could result in a dramatical drop in separation efficiency... For a cyclone, it is possible to improve separation efficiency and reduce pressure drop by increasing the cyclone height. However, an exceeded height increase could result in a dramatical drop in separation efficiency. In this study, experimental and computational fluid dynamics simulation results exhibit that the introduction of an apex cone at the dust outlet could avoid the risk of separation efficiency drop but lead to a continuous reducing of the pressure drop. Generally, the optimal cyclone height should be closely related to the natural vortex length. While, when the vortex end contracts into the separation space in the cyclone with an exceeded height, severe back-mixing of particles always occurs, which will result in the decrease of separation efficiency. Herein, it is found that when an apex cone is installed at the dust outlet, the vortex end can be grasped by the cone so as to weaken the back-mixing of particles.Meanwhile, the introduction of this apex cone can enhance the secondary separation to capture the back-mixed particles again so as to protect the efficiency. In addition, it is found that the enhanced secondary separation could come from either the stagnant current of axial velocity in the center or the improved tangential velocity of inner vortex whereas the forcibly extending the length of vortex to exceed its natural length will not significantly increase efficiency. 展开更多
关键词 Cyclone separator Cyclone height Natural vortex length Efficiency Secondary separation
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Estimating the Baseline Error of Wide-Swath Altimeters Using Nadir Altimeters via Numerical Simulation
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作者 MIAO Xiangying JIA Yongjun +1 位作者 LIN Mingsen MIAO Hongli 《Journal of Ocean University of China》 SCIE CAS CSCD 2022年第3期681-693,共13页
The baseline roll and length errors for wide-swath altimeters are major error sources in sea surface measurements that exhibit strong spatial characteristics in the cross-track direction.These errors can be identified... The baseline roll and length errors for wide-swath altimeters are major error sources in sea surface measurements that exhibit strong spatial characteristics in the cross-track direction.These errors can be identified and estimated in accordance with height differences at crossover points generated with nadir altimeters after excluding the interference from other error sources.Most of the wide-swath altimeter baseline estimation methods considered only the roll error in previous studies.A numerical simulation was conducted in this study using nadir altimeters to estimate the roll and length errors simultaneously to provide a selectable scheme for baseline error estimation and correction for future wide-swath altimeters.Results based on the parameters of the surface water and ocean topography mission and Sentinel-3A show that the correlation coefficient of the roll error between the estimated and simulated values is 0.89,while the correlation coefficient of the length error is 0.85.The sea surface height root mean square error(RMSE)can be reduced from 12.18 cm to 6.45 cm based on the two estimated results.The estimation effect can be increased by using multiple nadir altimeters to form an observation constellation.The numerical simulation of the five nadir altimeter constellation shows that the correlation coefficients of the roll and length errors would increase to 0.97,which reduces the sea surface height RMSE to 2.88 cm.In addition,the stability of this method is indicated in simulation experiments,which introduce different degrees of sea state errors. 展开更多
关键词 baseline error wide-swath altimeter roll angle baseline length nadir altimeter crossover point height difference
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An Experimental Study of Irregular Wave Forces on Multiple Quasi-ellipse Caissons 被引量:2
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作者 XiaozhongRen Peng Zhang +1 位作者 Yuxiang Ma Yufan Meng 《Journal of Marine Science and Application》 2014年第3期265-273,共9页
An experimental investigation of irregular wave forces on quasi-ellipse caisson structures is presented. Irregular waves were generated based on the Jonswap spectrum with two significant wave heights, and the spectrum... An experimental investigation of irregular wave forces on quasi-ellipse caisson structures is presented. Irregular waves were generated based on the Jonswap spectrum with two significant wave heights, and the spectrum peak periods range from 1.19 s to 1.81 s. Incident wave directions relative to the centre line of the multiple caissons are from 0&#176; to 22.5&#176;. The spacing between caissons ranges from 2 to 3 times that of the width of the caisson. The effects of these parameters on the wave forces of both the perforated and non-perforated caissons were compared and analyzed. It was found that the perforated caisson can reduce wave forces, especially in the transverse direction. Furthermore, the relative interval and incident wave direction have significant effects on the wave forces in the case of multiple caissons. 展开更多
关键词 relative wave length relative interval incident wave direction relative wave height quasi-ellipse caisson perforated quasi-ellipse caisson irregular wave forces
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MEASUREMENT OF NASAL FIGURE BY MAGNETIC RESONANCE IMAGING
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作者 陈腾 陈艳炯 +1 位作者 刘明俊 杨广夫 《Academic Journal of Xi'an Jiaotong University》 2001年第1期74-76,共3页
Objective To get the basic data of nasal figure of the Han nationality individuals in Xi'an area and provide for junsprudence and the reconstruction of skull. Methods Nasal height, length, depth and breadth of 313... Objective To get the basic data of nasal figure of the Han nationality individuals in Xi'an area and provide for junsprudence and the reconstruction of skull. Methods Nasal height, length, depth and breadth of 313cases in Xi'an area, which had different age and sex, were measured by magnetic resonance imaging (MRI). Results Image of MRI could clearly show the figure of nose and the position we selected were correct and accuracy. The specific data were: Nasal length (male:34. 47±4.29 ~52.20±3.47, female:33. 11±3.33~46. 94±3.83); Nasal height(male: 39.22±3.68~59.49±2.30, female: 33.89±3.95~51.75±3.68); Nasal depth(male: 11.89±1.76~16.68±2.48, female: 10.69±1. 81~16.46±2.04);Nasal breadth(male: 33. 09±3. 83~42. 49±2.72,female:32.00±1.94~38. 86±2.61). So the results were credible. Conclusion The nasal figure of individuals in Xi'an area is different as their different age and sex. It promotes that the influence factors of age and sex must be considered in the facial reconstruction and medico legally reconstructing skull. 展开更多
关键词 nasal figure magnetic resonance imaging nasal length nasal height nasal depth nasal breadth
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水稻秸秆拆解工艺参数优化及纤维自交织结构
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作者 孙恩惠 彭鵾 +5 位作者 曲萍 靳红梅 雍宬 陈玲 刘歆颖 黄红英 《农业工程学报》 EI CAS CSCD 北大核心 2024年第17期103-110,共8页
大尺寸高长径比纤维是影响非织造秸秆纤维生态毯质量的关键。机械揉搓是获得高长径比纤维的最佳处理技术工艺。该研究探究了揉丝机主轴转速和锤齿间隙对不同含水率秸秆纤维拆解揉丝的影响,其工艺参数为主轴转速、锤齿间隙及物料含水率,... 大尺寸高长径比纤维是影响非织造秸秆纤维生态毯质量的关键。机械揉搓是获得高长径比纤维的最佳处理技术工艺。该研究探究了揉丝机主轴转速和锤齿间隙对不同含水率秸秆纤维拆解揉丝的影响,其工艺参数为主轴转速、锤齿间隙及物料含水率,指标输出为秸秆丝化率与标定单位生产率,并对纤维自交织结构特性进行评价。结果表明,采用Box-Behnken响应面法(response surface method,RSM)开发了一个可确定输入和输出参数间的函数,2种评价指标模型均具有较高的可信度,决定系数分别为R^(2)>0.95,R^(2)>0.84。优化数学模型工艺参数:含水率41.2%,主轴转速2498 r/min,锤齿间隙12.84 mm组合下秸秆丝化率达96.93%,标定单位功率生产率为29.33 kg/(kW?h)。大尺寸高长径比秸秆纤维长度>70 mm和长宽比>80比例增幅分别达120.55%和16.01%,有效改善纤维自交织能力,所开发的RSM模型秸秆的实际揉搓拆解丝化率达96.27%,加工成本降低27.50元/t,可广泛应用于生产大尺寸纤维秸秆基高值农用制品。该研究为生物质秸秆的有效循环利用和高值化材料产业的绿色可持续发展提供重要依据和技术支撑。 展开更多
关键词 秸秆 纤维 参数优化 机械揉搓 高长径比 丝化率 响应面法
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山区大跨T型刚构桥设计要点
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作者 燕海蛟 黄康 +1 位作者 孙军举 王毅力 《公路交通技术》 2024年第3期41-54,共14页
以巫镇高速公路后溪河大跨T型刚构桥为研究对象,采用大型有限元程序Midas Civil建立主桥计算模型,对主桥承载力、受压区高度、主梁应力、主墩施工稳定、计算长度等方面进行分析探讨。结果表明:1)主梁结构尺寸及配束合理,承载力具有较高... 以巫镇高速公路后溪河大跨T型刚构桥为研究对象,采用大型有限元程序Midas Civil建立主桥计算模型,对主桥承载力、受压区高度、主梁应力、主墩施工稳定、计算长度等方面进行分析探讨。结果表明:1)主梁结构尺寸及配束合理,承载力具有较高的冗余度;2)箱梁底板厚度可适当降低,无需强制满足x≤ξbh 0,进而达到减轻结构自重的目的;3)主墩刚度适宜,施工大悬臂阶段稳定性较好;4)主墩进行强度、裂缝验算时,计算长度宜通过有限元屈曲分析,由欧拉临界力反算。 展开更多
关键词 大跨T型刚构 受压区高度 计算长度
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颈长、相对颈长和身高与颈椎病发病率之间的相关性研究
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作者 李杰 王杰 +2 位作者 陈冬梅 杨智杰 谢胜荣 《中国医学工程》 2024年第11期16-20,共5页
目的比较颈椎病患者与健康人的颈长、相对颈长和身高的差异性,为颈椎病的防治提供参考。方法选取2019年1月至2023年1月四川大学华西医院龙泉医院门诊收治的950例疑似颈椎病患者作为研究对象,根据患者是否确诊为颈椎病分为健康组(n=380)... 目的比较颈椎病患者与健康人的颈长、相对颈长和身高的差异性,为颈椎病的防治提供参考。方法选取2019年1月至2023年1月四川大学华西医院龙泉医院门诊收治的950例疑似颈椎病患者作为研究对象,根据患者是否确诊为颈椎病分为健康组(n=380)和颈椎病组(n=570),采用SPSS软件进行数据分析并借助Spearman相关性分析和Logistic回归,分析颈长、相对颈长和身高与颈椎病之间是否存在关联。结果两组在性别、年龄、职业、颈长、相对颈长和身高几个变量比较差异均有统计学意义(均P<0.05);不同颈椎病类型患者在性别、年龄、职业、颈长、相对颈长几个变量比较差异均有统计学意义(均P<0.05);相关分析显示:年龄、职业、颈长、相对颈长和身高与颈椎病发生具有显著相关性(均P<0.05);多元Logistic回归分析显示:年龄、职业、相对颈长和身高是导致颈椎病发生的独立危险因素[OR(95%CI)=2.579(1.249~3.007),3.049(1.461~2.978),4.192(1.467~2.659),4.983(1.273~3.042)]。结论相对颈长较长、身高较矮、年龄较大和脑力劳动为颈椎病的独立危险因素,可导致各类型颈椎病发病率上升。 展开更多
关键词 颈椎病 身高 颈长 相对颈长 相关性
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高速铁路大跨钢桁加劲连续刚构桥长期变形影响因素研究
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作者 占玉林 林金根 +3 位作者 张程 张志强 邵俊虎 陈文尹 《铁道标准设计》 北大核心 2024年第11期87-93,共7页
为研究钢桁长度和高度以及合龙顺序和顶推力对钢桁加劲连续刚构桥长期变形的影响,以某在建钢桁加劲连续刚构桥为对象,采用有限元软件建立实体模型,考虑混凝土收缩徐变作用,对恒载作用下运营20年内的变形进行分析,系统分析钢桁长度和高... 为研究钢桁长度和高度以及合龙顺序和顶推力对钢桁加劲连续刚构桥长期变形的影响,以某在建钢桁加劲连续刚构桥为对象,采用有限元软件建立实体模型,考虑混凝土收缩徐变作用,对恒载作用下运营20年内的变形进行分析,系统分析钢桁长度和高度对连续刚构桥长期变形的影响程度,同时利用结构力学原理推导不同合龙顺序下的顶推力解析式,探讨合龙顺序和顶推力对连续刚构桥长期变形的影响。结果表明:钢桁长度和高度的增加均可使挠跨比下降,均能提高桥梁的整体刚度,考虑到实际结构受力及施工难度,建议钢桁长度在桥梁中跨长度的3/4~7/8范围内选择,挠跨比下降42.3%~44.1%,为避免出现设计过于保守的情况,建议钢桁高度取12 m,挠跨比下降43.8%;推导出不同合龙顺序下的顶推力解析式,只与桥墩和主梁的参数有关,计算简便、概念清晰,可指导实际工程中顶推力的确定;不同合龙顺序对钢桁加劲连续刚构桥长期变形的影响较小,施加顶推力后可明显改善钢桁加劲连续刚构桥的长期变形,建议在施工过程中采用先中后边的合龙顺序,同时施加顶推力,在运营20年时边跨和中跨最大竖向变形分别下降34.6%和34.2%。 展开更多
关键词 高速铁路 铁路桥 钢桁加劲连续刚构桥 钢桁长度 钢桁高度 合龙顺序 顶推力 长期变形
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CFOSAT SWIM波谱仪中法产品差异性分析
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作者 徐莹 李秀仲 +3 位作者 顾经纬 孙从容 郭茂华 曹雯炯 《海洋气象学报》 2024年第4期30-37,共8页
中法海洋卫星(China-France Oceanography SATellite,CFOSAT)搭载了世界上第一颗专门探测二维海浪谱的雷达,即SWIM(Surface Waves Investigation and Monitoring)波谱仪。该雷达能通过旋转6个不同波束的方式扫描海面从而得到二维海浪谱... 中法海洋卫星(China-France Oceanography SATellite,CFOSAT)搭载了世界上第一颗专门探测二维海浪谱的雷达,即SWIM(Surface Waves Investigation and Monitoring)波谱仪。该雷达能通过旋转6个不同波束的方式扫描海面从而得到二维海浪谱信息,并通过控制天线旋转速度来控制沿轨向二维谱的分辨率。中法双方都会发布相同软件处理的波谱仪2级产品,但由于中法双方接收站位置不同、地面数据处理时输入的气象辅助数据源不完全一致,因此双方发布的2级产品有一定差异,这给波谱仪产品的应用带来不确定性。为了明晰不同数据下载源得到的相同版本波谱仪产品之间的差异,选取2024年3月中法相关单位发布的最新版本2级数据,采用5.0 s、3.0 s、1.0 s和0.1 s的时间匹配窗口,获取中法数据不同匹配时间下二维海浪谱3个波浪参数的一致性对比结果。结果表明:有效波高比较稳定,在半个地理单元的空间差别下仍然保持几乎不变的精度;随着匹配时间增大,主波波长和主波波向的差别越来越大,匹配时间为5.0 s时,二者分别达到约21.5 m和46.5°的差异,匹配时间为0.1 s时,其差异很小,表明中法不同地面处理系统输入的气象辅助数据源差异而引起的产品差别可以忽略。 展开更多
关键词 中法海洋卫星(CFOSAT) SWIM波谱仪 有效波高 主波波长 主波波向 微波遥感
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