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Online-SPE-UPLC-MS/MS检测生活污水中20种毒品
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作者 裴海燕 鄢茜 +5 位作者 周衍霄 张宏建 朱思琪 杨继伟 俞晓峰 赵鹏 《化学研究与应用》 CAS 北大核心 2024年第2期413-423,共11页
对生活污水的前处理进行优化,建立了一种在线固相萃取-超高效液相色谱-串联质谱法(Online-SPE-UPLC-MS/MS)同时测定污水中20种毒品及人口标记物的方法。用金属螯合剂Na_(2)EDTA·2H_(2)O处理污水后加入同位素内标,接着用滤膜过滤后... 对生活污水的前处理进行优化,建立了一种在线固相萃取-超高效液相色谱-串联质谱法(Online-SPE-UPLC-MS/MS)同时测定污水中20种毒品及人口标记物的方法。用金属螯合剂Na_(2)EDTA·2H_(2)O处理污水后加入同位素内标,接着用滤膜过滤后,以双柱交替模式上样。用Waters Oasis HLB固相萃取柱(2.1 mm×30 mm,20μm)进行富集浓缩后,用流动相将固相萃取柱上吸附的目标物反冲洗到Waters ACQUITY UPLC HSS T3色谱柱(2.1 mm×100 mm,1.8μm)上。柱温40℃,以乙腈-0.1%(体积分数)甲酸水溶液为流动相,采用梯度程序洗脱。采用电喷雾离子源正离子、多反应监测(MRM)模式定量检测。可替宁的线性范围在20~5000 ng·L^(-1),其余20种物质的线性范围在1~250 ng·L^(-1)之间,相关系数R2均大于0.99,检出限在0.01~0.25 ng·L^(-1)之间,加标回收率在91.57%~113.94%,精密度均小于15%。基于Online-SPE-UPLC-MS/MS建立了同时测定污水中20种毒品及人口标记物方法,该方法操作简单、灵敏高,具有良好的准确度和精密度,已成功应用于城市污水中的毒品检测,用于监测毒品滥用情况。 展开更多
关键词 在线固相萃取 双柱交替 超高液相色谱串联质谱 污水 毒品
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Thoughts and Practice on Some Problems about Research and Application of Two-Line Hybrid Rice 被引量:12
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作者 CHEN Li-yun LEI Dong-yang TANG Wen-bang XIAO Ying-hui 《Rice science》 SCIE 2011年第2期79-85,共7页
The main problems about research and application of two-line hybrid rice were reviewed, including the confusing nomenclature and male sterile lines classification, the unclear characteristics of photoperiod and temper... The main problems about research and application of two-line hybrid rice were reviewed, including the confusing nomenclature and male sterile lines classification, the unclear characteristics of photoperiod and temperature responses and the unsuitable site selection for male sterile line and hybrid rice seed production. In order to efficiently and accurately use dual-purpose genic male sterile lines, four types, including PTGMS (photo-thermo-sensitive genic male sterile rice), TGMS (thermo-sensitive genic male sterile rice), reverse PTGMS and reverse TGMS, were proposed. A new idea for explaining the mechanism of sterility in dual-purpose hybrid rice was proposed. The transition from sterile to fertile was involved in the cooperative regulation of major-effect sterile genes and photoperiod and/or temperature sensitive ones. The minor-effect genes with accumulative effect on sterility were important factors that affected the critical temperature of sterility transfer. In order to make better use of dual-purpose lines, the characterization of responses to photoperiod and temperature of PTGMS should be made and the identification method for the characterization of photoperiod and temperature responses of PTGMS should also be put forward. The optimal ecological site for seed production could be determined according to the historical climate data and the requirements for the meteorological conditions during the different periods of seed production. 展开更多
关键词 两系法杂交水稻 应用 光温敏核不育水稻 温敏核不育系 温度敏感 种子生产 反应特性 雄性不育
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Research on Theories and Techniques of Irrigation for Safeguarding Seed Production of Two-Line Hybrid Rice 被引量:3
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作者 ZOU Jiang-shi LUE Chuan-gen +2 位作者 YAO Ke-min HU Ning XIA Shi-jian 《Agricultural Sciences in China》 CAS CSCD 2006年第8期596-602,共7页
By inducing frequency, intensity and duration of lower temperature in the middle and last ten-day periods in August in the rice-growing areas of southern China, increasing temperature for safe seed production was defi... By inducing frequency, intensity and duration of lower temperature in the middle and last ten-day periods in August in the rice-growing areas of southern China, increasing temperature for safe seed production was defined as 2°C. During the sensitive period of fertility, characters of panicle height and canopy structure of TGMS rice, Pei’ai64S, were measured. Results showed that temperature changes caused by irrigation in fields were below 40 cm of rice plant, and heating effect was significant at 20 cm when the temperature was increased by 3.1°C. For the present study, the following irrigation techniques were put forth: the water depth of 15-20 cm, current water used, irrigating after 17:00 and bailing at 10:00 in sunny or cloudy weather, irrigating on whole day, in shady or rainy weather, increasing inflows and outflows in large fields. In the present experiment, pollen fertility and self-fertilized seed setting rate accepted that the techniques were feasible and effective for against lower temperature and safeguarding seed production of two-line hybrid rice. 展开更多
关键词 杂交水稻 种子处理 纯度 人工灌溉
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Causes of Poor Grain Plumpness of Two-Line Hybrids and Their Relationships to the Contents of Hormones in the Rice Grain 被引量:3
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作者 ZHAO Bu-hong ZHANG Hong-xi +1 位作者 ZHU Qing-sen YANG Jian-chang 《Agricultural Sciences in China》 CAS CSCD 2007年第8期930-940,共11页
This study was designed to elucidate the grain filling characteristics and the causes of poor grain plumpness of some two-line hybrid rice combinations and their hormonal mechanism. Six varieties, including three two-... This study was designed to elucidate the grain filling characteristics and the causes of poor grain plumpness of some two-line hybrid rice combinations and their hormonal mechanism. Six varieties, including three two-line hybrid rice combinations, that show differences in seed-setting and grain filling, were used. And the contents of starch, sucrose, zeatin (Z) + zeatin riboside (ZR), indole-3-acetic acid (IAA), and abscisic acid (ABA), the ethylene evolution rate, activities of sucrose synthase (SuSase) and starch synthase (StSase) in grains, the seed-setting and grain filling rate were investigated. The correlations amongst these were analyzed. The results showed that the poor grain filling of two-line hybrids was mainly attributed to the higher unfilled grain rate and the lower filling degree of inferior grains. During the early and mid grain filling periods, the sucrose content in inferior grains was greater than that in superior grains for the combinations with poor grain filling, indicating that the substrate concentration was not the principal factor for their slow grain filling and poor grain plumpness of the inferior grains of two-line hybrids. Z + ZR, IAA, and ABA in superior grains were obviously greater than those in inferior grains at early grain filling stage. The maximum and mean contents of Z + ZR, IAA, and ABA were positively very significantly correlated with the maximum and mean grain-filling rate, filling degree, and grain weight. The evolution rate of ethylene was greater in inferior grains than in superior grains and greater for the combinations with poor grain plumpness than those with good grain plumpness at the early or mid filling stages. The evolution rate of ethylene was negatively and significantly correlated with the grain filling rate, the grain filling degree, and the grain weight. Spraying ethephon (ethylene-releasing agent) at the early grain filling stage increased the evolution rate of ethylene, reduced the ABA content and activities of SuSase and StSase, and decreased the grain filling degree and the grain weight. The results were reversed when cobatous nitrate (an inhibitor of ethylene synthesis) was applied. The results suggested that the hormones and their balance play a role in the regulation of grain filling and enzymatic activities, and the poor grain filling is attributed to the low contents of Z + ZR, IAA, and ABA, and the high evolution rate of ethylene in the inferior grains of some two-line hybrid rice combinations. The results suggested that hormones play important roles in the grain filling of some two-line hybrid rice combinations, and their filling degree can be improved by regulating the hormonal contents. 展开更多
关键词 水稻 杂交技术 颗粒饱满 激素调节
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Exploiting Crop Heterosis by Two-line System Hybrids : Current Status and Future Prospects 被引量:1
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作者 袁隆平 《High Technology Letters》 EI CAS 1998年第1期92-97,共6页
ExploitingCropHeterosisbyTwo┐lineSystemHybrids:CurrentStatusandFutureProspectsYuanLongping(袁隆平)(ChinaNation... ExploitingCropHeterosisbyTwo┐lineSystemHybrids:CurrentStatusandFutureProspectsYuanLongping(袁隆平)(ChinaNationalHybridRiceR&DCe... 展开更多
关键词 Hybrid rice twoline SYSTEM HYBRIDS
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A Heuristic Method for Two-sided Assembly Line Balancing Problem 被引量:5
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作者 秦杏敏 金烨 《Journal of Shanghai Jiaotong university(Science)》 EI 2005年第1期61-65,共5页
A two-sided assembly line is typically found in plants producing large-sized products. Its advantages over a one-sided line and the difficulties faced in two-sided line balancing problems were discussed. A mathematica... A two-sided assembly line is typically found in plants producing large-sized products. Its advantages over a one-sided line and the difficulties faced in two-sided line balancing problems were discussed. A mathematical model for two-ALB problem was suggested. A modification of the “ranked positional weight” method, namely two-ALB RPW for two-ALB problems was developed. Experiments were carried out to verify the performance of the proposed method and the results show that it is effective in solving two-sided assembly line balancing problems. 展开更多
关键词 装配线平衡 双边装配线 人物延迟 阶位法 RPW
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Semi-Markovian Model of Two-Line Queuing System with Losses 被引量:2
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作者 Yuriy E. Obzherin 《Intelligent Information Management》 2016年第2期17-26,共10页
In the present paper, to build model of two-line queuing system with losses GI/G/2/0, the approach introduced by V.S. Korolyuk and A.F. Turbin, is used. It is based on application of the theory of semi-Markov processe... In the present paper, to build model of two-line queuing system with losses GI/G/2/0, the approach introduced by V.S. Korolyuk and A.F. Turbin, is used. It is based on application of the theory of semi-Markov processes with arbitrary phase space of states. This approach allows us to omit some restrictions. The stationary characteristics of the system have been defined, assuming that the incoming flow of requests and their service times have distributions of general form. The particular cases of the system were considered. The used approach can be useful for modeling systems of various purposes. 展开更多
关键词 two-line Queuing System with Losses Semi-Markov Process Stationary Distribution of Embedded Markov Chain Stationary Characteristics of System
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Effective Hybrid Teaching-learning-based Optimization Algorithm for Balancing Two-sided Assembly Lines with Multiple Constraints 被引量:7
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作者 TANG Qiuhua LI Zixiang +2 位作者 ZHANG Liping FLOUDAS C A CAO Xiaojun 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第5期1067-1079,共13页
Due to the NP-hardness of the two-sided assembly line balancing(TALB) problem, multiple constraints existing in real applications are less studied, especially when one task is involved with several constraints. In thi... Due to the NP-hardness of the two-sided assembly line balancing(TALB) problem, multiple constraints existing in real applications are less studied, especially when one task is involved with several constraints. In this paper, an effective hybrid algorithm is proposed to address the TALB problem with multiple constraints(TALB-MC). Considering the discrete attribute of TALB-MC and the continuous attribute of the standard teaching-learning-based optimization(TLBO) algorithm, the random-keys method is hired in task permutation representation, for the purpose of bridging the gap between them. Subsequently, a special mechanism for handling multiple constraints is developed. In the mechanism, the directions constraint of each task is ensured by the direction check and adjustment. The zoning constraints and the synchronism constraints are satisfied by teasing out the hidden correlations among constraints. The positional constraint is allowed to be violated to some extent in decoding and punished in cost function. Finally, with the TLBO seeking for the global optimum, the variable neighborhood search(VNS) is further hybridized to extend the local search space. The experimental results show that the proposed hybrid algorithm outperforms the late acceptance hill-climbing algorithm(LAHC) for TALB-MC in most cases, especially for large-size problems with multiple constraints, and demonstrates well balance between the exploration and the exploitation. This research proposes an effective and efficient algorithm for solving TALB-MC problem by hybridizing the TLBO and VNS. 展开更多
关键词 装配线平衡 优化算法 教学优化 多约束 混合式 连续属性 邻域搜索 全局最优解
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Interactions between two in-line drops rising in pure glycerin
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作者 Li Rao Zhengming Gao +1 位作者 Ziqi Cai Yuyun Bao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第10期1325-1334,共10页
The behaviors of time-dependent interaction between two buoyancy-driven in-line deformable drops rising in pure glycerin at Re b 1 were studied,where the diameter for the leading drops ranged from 9.51 mm to12.6 mm an... The behaviors of time-dependent interaction between two buoyancy-driven in-line deformable drops rising in pure glycerin at Re b 1 were studied,where the diameter for the leading drops ranged from 9.51 mm to12.6 mm and for trailing drops from 12.7 mm to 15.8 mm.The situation while a larger drop chasing a smaller one was specifically considered which typically led to the smaller drop "coating" the larger one.Two approaches,the geometric feature approach and the energy change one,were used to judge the starting and ending times of the interaction between two drops.Based on a conical wake model,the drag coefficient of two approaching drops was calculated.Due to the approaching effect of the trailing drop,the leading drop was accelerated and the average drag coefficient was smaller than that for a free rising single drop.The frequency spectrums of the lateral oscillation of two drops during the interaction were obtained by using Fourier analysis.The oscillation frequency of the interactional drops was also different from that for a free rising single drop because of the wake effect produced by the leading drop.Due to a superposition of the drop shape oscillation and the drop internal circulation,the transverse oscillation frequencies of two drops have the same trend during the approaching process. 展开更多
关键词 二同轴的落下 摆动 Fourier 分析 精力分析
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Calculation of the Two High Voltage Transmission Line Conductors’ Minimum Distance
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作者 Wenjie Huang Jinglin Zhu +1 位作者 Zhihang Du Zheng Zhang 《World Journal of Engineering and Technology》 2015年第3期89-96,共8页
In the design of high voltage transmission lines inevitably needed to change the arrangement of wires, and the distance between the wires directly affected by changing the arrangement of the wires. The distance betwee... In the design of high voltage transmission lines inevitably needed to change the arrangement of wires, and the distance between the wires directly affected by changing the arrangement of the wires. The distance between the wires is difficult to judge by experiences. Therefore, it is urgently to develop a way to accurately calculating the minimum distance between the wires when changing the arrangement between the two wires, and determine the minimum distance can meet the requirements of standards and regulations or not. Through the thinking, based on the balance equation and the space curve wire calculus method, a more accurate method of calculating the two wires in a variety of conditions the minimum spacing was derivated, and the sensitivity of the minimum distance was analysized based on the method. 展开更多
关键词 OVERHEAD Transmission lineS Distance of two lineS Equation of WIRE Balance WIRE SAG
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Inter-Circuit Fault Location Algorithm for Two-Parallel Transmission Line
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作者 张庆超 李大勇 +1 位作者 李晖 屈洪鑫 《Transactions of Tianjin University》 EI CAS 2003年第3期189-192,共4页
A novel numerical algorithm of fault location estimation for four-line fault without ground connection involving phases from each of the parallel lines is presented in this paper. It is based on one-terminal voltage a... A novel numerical algorithm of fault location estimation for four-line fault without ground connection involving phases from each of the parallel lines is presented in this paper. It is based on one-terminal voltage and current data. The loop and nodal equations comparing faulted phase to non-faulted phase of two-parallel lines are introduced in the fault location estimation model, in which the source impedance of a remote end is not involved. The effects of load flow and fault resistance on the accuracy of fault location are effectively eliminated, therefore a precise algorithm of locating fault is derived. The algorithm is demonstrated by digital computer simulations. 展开更多
关键词 内部电路故障定位算法 并行传输线 输电线路故障 电路理论
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One-End Data Method for Fault Position Estimate of Two-Parallel Transmission Lines
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作者 张庆超 刘飞 +1 位作者 武永峰 宋文南 《Journal of Beijing Institute of Technology》 EI CAS 2003年第1期105-108,共4页
An accurate numerical algorithm for three-line fault involving different phases from each of two-parallel lines is presented. It is based on one-terminal voltage and current data. The loop and nodel equations comparin... An accurate numerical algorithm for three-line fault involving different phases from each of two-parallel lines is presented. It is based on one-terminal voltage and current data. The loop and nodel equations comparing faulted phase to non-faulted phase of two-parallel lines are introduced in the fault location estimation modal, in which the faulted impedance of remote end is not involved. The effect of load flow and fault resistance on the accuracy of fault location are effectively eliminated, therefore an accurate algorithm of locating fault is derived. The algorithm is demonstrated by digital computer simulations and the results show that errors in locating fault are less than 1%. 展开更多
关键词 电力系统 继电保护 故障定位 数值计算 输电线路
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Observation of the Two-Dimensional Distribution of Impurity Line Emissions Using a Space-Resolved EUV Spectrometer in LHD
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作者 王二辉 S.MORITA +1 位作者 M.GOTO 董春凤 《Plasma Science and Technology》 SCIE EI CAS CSCD 2013年第2期106-109,共4页
A space-resolved EUV spectrometer for measuring the one-dimensional distribution of impurity line emissions in Large Helical Device (LHD) has been upgraded to measure two- dimensional distributions of impurity line em... A space-resolved EUV spectrometer for measuring the one-dimensional distribution of impurity line emissions in Large Helical Device (LHD) has been upgraded to measure two- dimensional distributions of impurity line emissions with an extension of working wavelength range to 30~650 A. The two-dimensional measurement is performed by scanning the observation chord horizontally. A rectangular plasma region of 520 × 700 mm 2 in vertical and horizontal sizes can be observed during a single horizontal scan. The horizontal scan requires a time duration of 5 s at least. The spatial resolution is 10 mm in the vertical direction when a spatial-resolution slit of 0.2 mm in width is adopted. Although a spatial resolution in the toroidal direction is 75 mm, it is a function of CCD exposure time and horizontal scanning speed. Two-dimensional distribution of EUV line emissions from several impurities has been successfully observed for the first time from steady discharges in LHD. In this paper two-dimensional distributions of He II (303.78 A), C V (40.27 A), C VI (33.73 A) and Fe XX (132.85 A) located at different radial positions are presented with simple analysis on the magnetic field structure of LHD. 展开更多
关键词 空间分辨率 二维分布 LHD EUV 光谱仪 杂质 水平扫描 辐射
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Off-line Two-Dimensional Gas Chromatography-Mass Spectrometry for Analysis of Essential Oil of Medicinal Herb──Use of Absorption Trap
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作者 MA Xue-yi PAN Hui-ping and CHEN Yao-zu(iNational Laboratory of Applied Organic Cheniistry and Deparrmentof Chemistry, Lanzhou University, Lanzhou,7300007)(Department of Chemistry , Zhejiang Univer,ity, Hangzhou, 310027) 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 1994年第4期291-296,共6页
Off-lineTwo-DimensionalGasChromatography-MassSpectrometryforAnalysisofEssentialOilofMedicinalHerb──UseofAbso... Off-lineTwo-DimensionalGasChromatography-MassSpectrometryforAnalysisofEssentialOilofMedicinalHerb──UseofAbsorptionTrapMAXue-y... 展开更多
关键词 OFF-line two-DIMENSIONAL GAS chromatography ESSENTIAL OIL Absorp-tion TRAP Cymbopogon distans
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Selection of Homozygous Cotton Lines Transformed with Two Insect-Resistant Genes 被引量:1
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作者 WUJia-he TIANYing-chuan +6 位作者 LUOXiao-li GUOHong-nian SHIYue-jin CHENXiao-ying: JIAYan-tao XIAOJuan-li ZHANGXian-long 《Agricultural Sciences in China》 CAS CSCD 2003年第9期950-956,共7页
A plant expression vector containing a chimeric Bt29K gene coding for the activated Cry1Ac protein and the arrowhead proteinase inhibitior gene API B were introduced into the cotton cultivar Jihe321 mediated by Agroba... A plant expression vector containing a chimeric Bt29K gene coding for the activated Cry1Ac protein and the arrowhead proteinase inhibitior gene API B were introduced into the cotton cultivar Jihe321 mediated by Agrobactertium tumefaciens. Based on the results of kanamycin resistant testing, PCR detection for both foreign genes and insect bioassay using Heliethis armigera , nine transgenic homozygous cotton lines with insect resistance of more than 90% and better agronomic traits were bred through six generations from the original transgenic plants. Results from insect bioassay and sequence analysis of the PCR products of plants from some homozygous lines indicated that the chimeric Bt29K gene was stably inherited in these transgenic cotton lines. The main agronomic characters of these homozygous cotton lines, such as boll productivity and fibre strength, were better than that of the original cotton cv. Jihe321. 展开更多
关键词 棉花 双抗虫基因 转基因育种 Bt29K基因 API-B基因 棉铃虫 Jihe321品系 筛选
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光温敏两系不育系‘稆S’的选育与应用
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作者 陈小玲 蒋云林 +3 位作者 钱子燕 王泓超 程祖锌 林荔辉 《亚热带农业研究》 2024年第1期9-14,共6页
[目的]选育优良的光温敏两系不育系,以提高其杂种后代的产量和品质。[方法]采用光温敏两系不育系‘RGD-7S’为母本与三系保持系‘中浙B’杂交,经5年9代的系谱法选育,育成不育性稳定、稻米品质优、异交特性好、株叶形态优良的光温敏两系... [目的]选育优良的光温敏两系不育系,以提高其杂种后代的产量和品质。[方法]采用光温敏两系不育系‘RGD-7S’为母本与三系保持系‘中浙B’杂交,经5年9代的系谱法选育,育成不育性稳定、稻米品质优、异交特性好、株叶形态优良的光温敏两系不育系‘稆S’,并分析了其主要特征特性及杂种优势。[结果]‘稆S’不育性稳定,育性转换临界温度<23℃,稳定不育期127 d左右。该不育系制种产量高,异交特性好,柱头外露率78.62%,其中双边外露率39.74%。采用‘稆S’配组的高产、优质两系杂交稻组合‘稆两优质美’先后通过了福建省和海南省农作物品种审定。[结论]光温敏两系不育系‘稆S’不育性稳定,育性转换临界温度低,稻米品质优,配合力强,应用前景广泛。 展开更多
关键词 水稻 光温敏两系不育系 优质 选育
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NEAR CRACK LINE ELASTIC-PLASTIC ANALYSIS FOR A FINITE PLATE LOADED BY TWO PAIRS OF ANTIPLANE POINT FORCES 被引量:1
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作者 王成 张录坤 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1998年第6期547-553,共7页
In this paper, the improved near crack line analysis method proposed in Refs. [1]and [2] is used to investigate a center crack loaded by two pairs of antiplane pointforces in a finite plate in an elastic-perfectly pla... In this paper, the improved near crack line analysis method proposed in Refs. [1]and [2] is used to investigate a center crack loaded by two pairs of antiplane pointforces in a finite plate in an elastic-perfectly plastic solid. And the analytical solutionsare obtained, thai is elastic-plastic stress fields near the crack line and the taw that thelength of foe plastic zone along the crack line is varied with an external loads and thebearing capacity of a finite plate with a center crack. The results of this paper aresufficiently precise near the crack line because the assumptions of the Small scaleyielding theory have not been used and no other assumptions have been taken. 展开更多
关键词 NEAR crack line analysis two PAIRS of antiplane POINT FORCES finite plate elastic-plastic analytical solutions
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Two semi-solid die-casting production lines of Xuzhou Die- casting Technology Co., Ltd. officially put into operation
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《China Foundry》 SCIE 2017年第6期539-539,共1页
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非圆形隧洞衬砌支护下应力与位移的新解法
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作者 吕爱钟 崔耀启 +1 位作者 蔡辉 马耀财 《工程地质学报》 CSCD 北大核心 2024年第1期206-215,共10页
以往在利用平面弹性复变函数方法进行衬砌支护作用下非圆形隧洞的力学分析时,一般将洞室外域保角映射到象平面的单位圆外域,并认为可以利用同一个映射函数将衬砌截面映射到象平面的圆环域内。当衬砌厚度很薄时,这种方法是可行的,而当衬... 以往在利用平面弹性复变函数方法进行衬砌支护作用下非圆形隧洞的力学分析时,一般将洞室外域保角映射到象平面的单位圆外域,并认为可以利用同一个映射函数将衬砌截面映射到象平面的圆环域内。当衬砌厚度很薄时,这种方法是可行的,而当衬砌相对较厚时,利用同一映射函数所得到的衬砌截面形状发生严重失真。为解决此问题,本文引入两套映射函数,分别将洞室外域映射到象平面的单位圆的圆外域,衬砌截面映射到圆环域。这种方法可以适应于不同的衬砌厚度,利用这种方式获得的衬砌截面,在衬砌较厚时仍能保证衬砌厚度相对均匀。在求解解析函数过程中不再采用传统的幂级数解法,而是使用边界配点法,将两套映射函数结合,获得了该问题的应力解和位移解。本文以马蹄形隧洞为例,求解结果与ANSYS软件所得数值解吻合很好,分析了衬砌厚度对隧洞应力和位移的影响。根据本文解答可以方便、快捷地进行相近条件下隧道的初步设计。 展开更多
关键词 复变函数方法 非圆形压力隧洞 均匀厚度衬砌 两套映射函数 边界配点法
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海南两系杂交稻制种适宜区域与时段选择
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作者 杜关 车秀芬 +3 位作者 张吉贞 李伟光 邹海平 吕润 《热带农业科学》 2024年第2期9-13,共5页
掌握两系杂交稻在海南制种的气象灾害风险,是科学合理安排两系杂交稻制种生长期的重要依据。针对两系杂交水稻制种过程中的3个关键阶段(育性敏感安全期、抽穗扬花授粉安全期和灌浆安全期)的气象灾害概率进行分析,通过数据分析和实例验... 掌握两系杂交稻在海南制种的气象灾害风险,是科学合理安排两系杂交稻制种生长期的重要依据。针对两系杂交水稻制种过程中的3个关键阶段(育性敏感安全期、抽穗扬花授粉安全期和灌浆安全期)的气象灾害概率进行分析,通过数据分析和实例验证得出各地区制种的安全时段,以及需重点考虑的气象灾害。海南两系杂交水稻育性敏感安全期可安排在3月上旬至4月中旬,三亚、陵水地区从3月上旬开始;乐东、东方、昌江从3月下旬至4月上旬开始;临高在4月中旬至下旬左右,不同界限温度变化略有先后。各地花期的阴雨天气较为随机且概率较小;临高、昌江地区制种重点关注灌浆安全期干热风等危害,提早播种。目前海南水稻制种区域和时段合理,可根据不育系材料不育起点温度阈值和耐受低温时间长短,适当调整播种时段。 展开更多
关键词 两系杂交水稻 制种 风险 气象灾害 海南
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