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对金斯定则的几点认识 被引量:1
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作者 高崇伊 《天文学报》 CSCD 北大核心 2002年第4期366-374,共9页
用物理学基本定律可导出金斯经验定则,它似应称为金斯定则.该定则的速度、高度或能量等表述完全等效,可随意选用.用能量观点更容易解释此定则.满足金斯定则只是给定的粒子成为具有稠密大气的行星或卫星的主要大气成分的必要条件.该定则... 用物理学基本定律可导出金斯经验定则,它似应称为金斯定则.该定则的速度、高度或能量等表述完全等效,可随意选用.用能量观点更容易解释此定则.满足金斯定则只是给定的粒子成为具有稠密大气的行星或卫星的主要大气成分的必要条件.该定则的适用范围可用方程或其图像表示,也能用诺模图确定;它适用于太阳系内的行星、卫星、小行星、流星体和像柯伊伯带天体与半人马族星这样的外太阳系天体.此定则现在仍有普遍的现实意义. 展开更多
关键词 金斯定则 卫星 柯伊伯带 小行量 行星大气 行星物理学
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Effects of Sowing Rate on Marginal Superiority and Yield of Wheat in Wheat-cotton Intercropping System
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作者 王树林 祁虹 +4 位作者 王燕 张谦 冯国艺 林永增 梁青龙 《Agricultural Science & Technology》 CAS 2015年第12期2649-2652,共4页
In the wheat-cotton intercropping system, total 6 sowing rates (187.5, 225.0, 262.5, 300.0, 337.5 and 375.0 kg/hm2) were arranged, and the effects of sowing rate on marginal superiority and yield of wheat were inves... In the wheat-cotton intercropping system, total 6 sowing rates (187.5, 225.0, 262.5, 300.0, 337.5 and 375.0 kg/hm2) were arranged, and the effects of sowing rate on marginal superiority and yield of wheat were investigated. The re- sults showed that the effect of sowing rate on inner-line wheat was greater than that on side-line wheat; with the increased sowing rate, the marginal superiority of panicle number was reduced in overall, and the difference in panicle number be- tween inner and side lines was decreased from 9.0×10^5/hm2 (sowing rate of 187.5 kg/hm2) to 7.8×10^5/hm2 (sowing rate of 375.0 kg/hm2); the marginal superiority of grains per spike was increased first and then reduced, and the largest difference in grains per spike between the inner and side lines reached 4.6 under the sowing rate of 300.0 kg/hm2; the marginal superiority of 1 000-grain weight and yield was gradually increased, and the largest difference in 1 000-grain weight between the inner and side lines reached 3.9 g under the sowing rate of 337.5 kg/hm2, and in yield reached 3 136.5 kg/hm2under the sowing rate of 375.0 kg/hm2. The effects of sowing rate on the three yield factors of intercropped wheat ranked as panicle number 〉 grains per spike 〉 1 000-grain weight. The appropriate sowing rate of wheat was 225.0-262.0 kg/hm2 in the wheat-cotton intercropping system. 展开更多
关键词 Wheat-cotton intercropping WHEAT Sowing rate Marginal superiority YIELD
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遥测地球未来
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作者 刘明 李之 《科技潮》 1994年第3期50-52,共3页
在宇宙中诞生的任何物质都躲不过演化和死亡的命运,地球也不例外。地球诞生至今已46亿年,这大约是其生涯的一半。以往地球自己不断整理环境,孕育生命并供养它们。往后剩下的50亿年,地球又将如何?现代科学不仅知道它的过去,也逐渐能预知... 在宇宙中诞生的任何物质都躲不过演化和死亡的命运,地球也不例外。地球诞生至今已46亿年,这大约是其生涯的一半。以往地球自己不断整理环境,孕育生命并供养它们。往后剩下的50亿年,地球又将如何?现代科学不仅知道它的过去,也逐渐能预知它的未来。我们遥测地球的未来,或许可从万物之母地球的一生中找到人类应走的道路。 100年后。 展开更多
关键词 地球 全球变暖 小行量 碰撞 磁场 冰期
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The Finite Element Analysis for Parallel-wire Capacitance Probe in Small Diameter Two-phase Flow Pipe 被引量:1
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作者 翟路生 金宁德 +1 位作者 高忠科 黄旭 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2013年第7期813-819,共7页
This paper presents a novel capacitance probe, i.e., paraUel-wire capacitance probe (PWCP), for two-phase flow measurement. Using finite element method (FEM), the sensitivity field of the PWCP is investigated and ... This paper presents a novel capacitance probe, i.e., paraUel-wire capacitance probe (PWCP), for two-phase flow measurement. Using finite element method (FEM), the sensitivity field of the PWCP is investigated and the optimum sensor geometry is determiend in term of the characterisitc parameters. Then, the response of PWCP for the oil-water stratified flow is calculated, and it is found the PWCP has better linearity and sensitivity to the variation of water-layer thickness, and is almost independant of the angle between the oil-water interface and the sensor electrode. Finally, the static experiment for oil-water stratified flow is carried out and the calibration method of liquid holdup is presented. 展开更多
关键词 parallel-wire capacitance probe finite element analysis sensitivity field oil-water stratified flow
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Minimum Cycle of Row Vector of a Generalized Circulant Fuzzy Matrix
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作者 冼国荣 陈卓荣 《Chinese Quarterly Journal of Mathematics》 CSCD 1997年第1期104-110, ,共7页
In this paper,we intreduce the concept and discuss the properties of minimum cycle of row vector in a generalized circulant Fuzzy matrix. We present a new expression for circulant Fuzzy matrix,and discuss some propert... In this paper,we intreduce the concept and discuss the properties of minimum cycle of row vector in a generalized circulant Fuzzy matrix. We present a new expression for circulant Fuzzy matrix,and discuss some properties of the idempotent elements of the semigroup of generalized circulant Fuzzy matrixes in connection with minimum cycle of row vector. 展开更多
关键词 generalized circulant Fuzzy matrix SEMIGROUP VECTOR CYCLE idempotent element
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Application of Lyapunov exponent algorithm in balise signal chaotic oscillator detection 被引量:1
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作者 ZHANG Hongyan WANG Ruifeng 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2021年第3期281-286,共6页
To improve the detection accuracy of the balise uplink signal transmitted in a strong noise environment,we use chaotic oscillator to detect the balise uplink signal based on the characteristics of the chaotic system t... To improve the detection accuracy of the balise uplink signal transmitted in a strong noise environment,we use chaotic oscillator to detect the balise uplink signal based on the characteristics of the chaotic system that is sensitive to initial conditions and immune to noise.Combining with the principle of Duffing oscillator system used in weak signal detection and uplink signal feature,the methods and steps of using Duffing oscillator to detect the balise signal are presented.Furthermore,the Lyapunov exponent algorithm is used to calculate the critical threshold of the Duffing oscillator detection system.Thus,the output states of the system can be quantitatively judged to achieve demodulation of the balise signal.The simulation results show that the chaotic oscillator detection method for balise signal based on Lyapunov exponent algorithm not only improves the accuracy and efficiency of threshold setting,but also ensures the reliability of balise signal detection. 展开更多
关键词 Duffing oscillator Lyapunov exponent Jacobian algorithm small data sets balise uplink signal
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Development and validation of a rapid psychosocial well-being screening tool in patients with metastatic breast cancer
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作者 Bhumipat Thanasansomboon Songphan Choemprayong +3 位作者 Napa Parinyanitikul Uthai Tanlamai Manika Wisessathorn Yupin Patarapongsant 《International Journal of Nursing Sciences》 CSCD 2022年第3期303-312,I0002,共11页
Objective The aim of this study was to develop and validate a rapid psychosocial well-being screening tool for metastatic breast cancer patients(MBC-PsySoc-Well-being).Methods Applying a mixed method approach,the stud... Objective The aim of this study was to develop and validate a rapid psychosocial well-being screening tool for metastatic breast cancer patients(MBC-PsySoc-Well-being).Methods Applying a mixed method approach,the study was conducted in two phases.Phase 1,a focus group method was employed for item development,and three focus group sessions were conducted,with patients,caregivers,and medical professionals,respectively.Phase 2,validity and reliability testing were performed.Five experts reviewed items for content validity.Construct validity,criterion-related validity,internal consistency,and test-retest reliability were conducted among a sample of 53 patients with metastatic breast cancer.Results Six themes were qualitatively analyzed based on focus group participants’responses.Eight items were then developed based on these themes.The index of Item-Objective Congruence scored by the experts ranged from 0.6 to 1.0.An exploratory factor analysis yielded three factors:Being curious and active in information seeking,Enthusiasm to return to a normal life,and Adjusting to positive lifestyle.The total scores of MBC-PsySoc-Well-being and the European Organization for Research and Treatment of Cancer’s Quality of Life Core Questionnaire(EORTC QLQ-C30)were moderately correlated(r=0.404,P=0.003).Cronbach’sαcoefficient of the overall scale was 0.686.Pearson correlation coefficients of items between two tests within 14-day ranged from 0.410 to 0.673.Conclusion This study represents an initiative to develop a rapid psychosocial well-being screening tool for patients with metastatic breast cancer.The results from validity and reliability testing indicate that the scale is moderately suitable for application to patients with metastatic breast cancer.However,a larger scale study should be further administered to confirm the validity and reliability of the measurement. 展开更多
关键词 Breast neoplasms Focus groups Information seeking behavior MEASUREMENT Psychosocial functioning Quality of life
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Release of Stem Rust Resistant Wheat Varieties for Commercial Production in Kenya
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作者 P. N. Njau R. Wanyera +2 位作者 D. Singh R. Singh M. Gethi 《Journal of Agricultural Science and Technology(A)》 2011年第4X期587-598,共12页
Detection in 1999 of a new stem rust (Puccinia graminis f. sp. tritici) race Ug99 in Uganda with broad virulence including the virulence for Sr31 and its migration to Kenya and Ethiopia has been recognized as a sign... Detection in 1999 of a new stem rust (Puccinia graminis f. sp. tritici) race Ug99 in Uganda with broad virulence including the virulence for Sr31 and its migration to Kenya and Ethiopia has been recognized as a significant threat to local and world wheat production. All the Current Kenyan commercial varieties are susceptible to this race. This study was aimed at identifying suitable wheat varieties with resistance to Ug99 and replacing the susceptible commercial varieties through multi-locational testing and variety release. Thirty three lines were identified from a prescreen population of 104 lines and tested in 3 wheat growing regions in Kenya for two seasons in 2006 and 2007. The resulting four superior lines were evaluated under the National Performance Trial (NPT) where two lines which out-performed the best check variety were released as for commercial production. 'Robin' was the best line and out yielded the commercial variety by 27%. "Eaglel0" was the second best and was better significantly than the check variety. These two lines which combined both adult plant resistant gene Sr2 complex and other major genes are expected to have some durable resistance and may be used to replace the current susceptible commercial varieties grown in Kenya. 展开更多
关键词 Multi-locational testing adult plant stem rust resistance bread wheat.
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Energy System Selection for Small Underwater Vehicles 被引量:2
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作者 G.T.Reader J.G.Hawley 《Journal of Thermal Science》 SCIE EI CAS CSCD 1994年第1期7-14,共8页
The oceans cover almost three-quarters of the earth's surface and provide a highway for commerceor conquest and constitute a rich source of nutrients, materials and energy. The exploration and exploitation of ocea... The oceans cover almost three-quarters of the earth's surface and provide a highway for commerceor conquest and constitute a rich source of nutrients, materials and energy. The exploration and exploitation of oceanic resources accelerated in the 1970s because of the emerging offshore oil and gasindustry. The extraction and national protection of these and other resources will increase rapidlyin the next century and in support of these activities one of the most useful tools will be the smallunderwater vehicle. However, if these vehicles are to carry out the envisaged tasks in a cost--effectiveand mission-effective manner they will require high performance energy systems. A number of suchsystems are being developed and the problem arises as which one to select for a particular task. In thispaper the development of software based techniques for the selection of energy systems is described. 展开更多
关键词 energy system selection small underwater vehicles
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