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Yield and Nutritive Values of Semi- and Non-Fall Dormant Alfalfa Cultivars under Late-Cutting Schedule in California’s Central Valley
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作者 Sultan Begna Dan Putnam +2 位作者 Dong Wang Khaled Bali Longxi Yu 《American Journal of Plant Sciences》 CAS 2024年第10期858-876,共19页
California is one of the major alfalfa (Medicago sativa L) forage-producing states in the U.S, but its production area has decreased significantly in the last couple of decades. Selection of cultivars with high yield ... California is one of the major alfalfa (Medicago sativa L) forage-producing states in the U.S, but its production area has decreased significantly in the last couple of decades. Selection of cultivars with high yield and nutritive value under late-cutting schedule strategy may help identify cultivars that growers can use to maximize yield while maintaining area for sustainable alfalfa production, but there is little information on this strategy. A field study was conducted to determine cumulative dry matter (DM) and nutritive values of 20 semi- and non-fall dormant (FD) ratings (FD 7 and FD 8 - 10, respectively) cultivars under 35-day cut in California’s Central Valley in 2020-2022. Seasonal cumulative DM yields ranged from 6.8 in 2020 to 37.0 Mg·ha−1 in 2021. Four FD 8 - 9 cultivars were the highest yielding with 3-yrs avg. DM greater than the lowest yielding lines by 46%. FD 7 cultivar “715RR” produced the highest crude protein (CP: 240 g·Kg−1) while FD 8 cultivar “HVX840RR” resulted in the highest neutral detergent fiber digestibility (NDFD: 484 g·Kg−1, 7% greater than the top yielding cultivars) but with DM yield intermediate. Yields and NDFD correlated positively but weakly indicating some semi- and non-FD cultivars performing similarly. These results suggest that selecting high yielding cultivars under 35-day cutting schedule strategy can be used as a tool to help growers to maximize yield while achieving good quality forages for sustainable alfalfa production in California’s Central Valley. 展开更多
关键词 ALFALFA Maximizing Yield Nutritive Value CULTIVAR cutting Schedule Production area California
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Geochemistry of borehole cutting shale and natural gas accumulation in the deepwater area of the Zhujiang River Mouth-Qiongdongnan Basin in the northern South China Sea 被引量:3
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作者 GAO Gang ZHANG Gongcheng +3 位作者 CHEN Guo GANG Wenzhe SHEN Huailei ZHAO Ke 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2018年第2期44-53,共10页
The Qiongdongnan Basin and Zhujiang River(Pearl River) Mouth Basin, important petroliferous basins in the northern South China Sea, contain abundant oil and gas resource. In this study, on basis of discussing impact... The Qiongdongnan Basin and Zhujiang River(Pearl River) Mouth Basin, important petroliferous basins in the northern South China Sea, contain abundant oil and gas resource. In this study, on basis of discussing impact of oil-base mud on TOC content and Rock-Eval parameters of cutting shale samples, the authors did comprehensive analysis of source rock quality, thermal evolution and control effect of source rock in gas accumulation of the Qiongdongnan and the Zhujiang River Mouth Basins. The contrast analysis of TOC contents and Rock-Eval parameters before and after extraction for cutting shale samples indicates that except for a weaker impact on Rock-Eval parameter S2, oil-base mud has certain impact on Rock-Eval S1, Tmax and TOC contents. When concerning oil-base mud influence on source rock geochemistry parameters, the shales in the Yacheng/Enping,Lingshui/Zhuhai and Sanya/Zhuhai Formations have mainly Type Ⅱ and Ⅲ organic matter with better gas potential and oil potential. The thermal evolution analysis suggests that the depth interval of the oil window is between 3 000 m and 5 000 m. Source rocks in the deepwater area have generated abundant gas mainly due to the late stage of the oil window and the high-supper mature stage. Gas reservoir formation condition analysis made clear that the source rock is the primary factor and fault is a necessary condition for gas accumulation. Spatial coupling of source, fault and reservoir is essential for gas accumulation and the inside of hydrocarbon-generating sag is future potential gas exploration area. 展开更多
关键词 cutting shale organic geochemistry gas accumulation deepwater area Qiongdongnan Basin Zhujiang River Mouth Basin
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CHARACTERISTICS OF SMALL RODENT COMMUNITY IN DIFFERENT AGED CUT-OVER AREAS IN DAILING MOUNTAIN
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作者 高中信 姜洪海 +1 位作者 高继宏 赵淑琴 《Journal of Northeast Forestry University》 SCIE CAS CSCD 1994年第4期52-57,共6页
The field investigation of small rodent community was made in Liangshui Reserve, Heilongiiang Province, in 1992. Species composition and percentage of each species of the small rodents in different aged clear-cut-over... The field investigation of small rodent community was made in Liangshui Reserve, Heilongiiang Province, in 1992. Species composition and percentage of each species of the small rodents in different aged clear-cut-over areas were analyzed. The change of rodent community was associated with the change of vegetation cover. Forest harvest, which results in change of light, temperature, water and othcr ecological factors, made change of vegetation cover and was the main cause for the change of small rodent community. The small rodents were low in number of species population and diversity index in the inatial stages after clear cutting. The diversity index of rodents in order of different aged cut-over areas were 5-year-old area >20-year-old area > 28-year-old area > 1 -year-old area > 10-year-old area. 展开更多
关键词 cut-over area Rodent community Forest harvest Diversity index
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Ground pressure law of fully mechanized large cutting height face in extremely-soft thick seam and stability control in tip-to-face area
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作者 刘长友 常兴民 +3 位作者 黄炳香 魏民涛 王君 王建树 《Journal of Coal Science & Engineering(China)》 2007年第4期410-414,共5页
When stepped coal getting technology was applied to high seam mining working face, with field observations the following aspects of working face were analyzed based on the inherent conditions of extremely soft thick s... When stepped coal getting technology was applied to high seam mining working face, with field observations the following aspects of working face were analyzed based on the inherent conditions of extremely soft thick seam mined by Liangbei Mine, such as the brokenness and activity law of rock seam in the working face, the law of load-bearing of its supports, and the instability character of coal or rock in tip-to-face area. The following are the major laws. Pressure intensity of roof in high seam mining with extremely soft thick seam is stronger than one in slicing and sublevel-caving as a whole. But the greater crushing deformation of coal side makes pressure intensity of roof in the middle of working face be equivalent to one in sublevel-caving. In the middle of working face the roof brokenness has less dynamic load effect than roof brokenness in the two ends of working face. The brokenness instability of distinct pace of roof brings several load-bearings to supports. In condition of extremely soft thick seam, the ratio of resistance increment of supports in two ends of working face is obviously greater than that of supports in the middle. Most sloughing in coal side is triangular slop sloughing caused by shear slipping in high seam mining with extremely soft thick seam. Ultrahigh mining is the major reason for roof fall. Instability of coal or rock in tip-to-face area can be controlled effectively with the methods such as improving setting load of supports, mining along roof by reinforcing floor and protecting the immediate roof in time, and so on. 展开更多
关键词 extremely-soft thick coal seam large cutting height roof fracture coal-rock in tip-to-face area control
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Study on the Introduction and Screening of Cut Roses in the Tropical Coastal Area of China 被引量:5
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作者 林亚琼 陈冠铭 +2 位作者 许惠秋 汪李平 乔顺法 《Agricultural Science & Technology》 CAS 2012年第10期2123-2128,共6页
[Objective] This study aimed to select suitable cultivars of cut roses with prominent comprehensive performance which is suitable for the commercial promotion in the tropical region of South Hainan Province,including ... [Objective] This study aimed to select suitable cultivars of cut roses with prominent comprehensive performance which is suitable for the commercial promotion in the tropical region of South Hainan Province,including Sanya and the low-altitude area.[Method] Introduction experiment and production test were designed to observe the agronomic and economic traits of cultivars in a rose resources nursery established in Sanya.[Result] Through observation in the resources garden,18 varieties were chosen to conduct the introduction experiment,of which 8 varieties were selected to accomplish the production test.The results of the production test showed that 'Vendela','Golden Emblem','Samantha' and 'Tineke' showed the best adaptability;the cut flower quality of 'Carola','Black Magic' and 'Golden Emblem' belonged to the first grade;the yield of 'Movie Star','Golden Emblem' and 'Black Magic' was more than one million per hm2;except 'Golden Emblem',the vase life of the other seven cultivars was more than 10 days;'Carola','My Choice' and 'Perfume White' had better disease-and insect-resistance;'Carola','Vendela','Rouge Meilland','Tineke','Golden Emblem','Samantha','Perfume White','Saiun','Asagumo' and 'Double Delight' were more resistant to blackspot,while 'Black Magic','Versilla','Alec's Red' and 'Movie Star' were less resistant to blackspot.[Conclusion] Cultivars of cut roses were able to grow and develop normally in the tropical coastal area of Hainan Province,including South Hainan and Sanya,where it was appropriate for the production of cut roses.However,it is necessary to pay attention to the prevention and control of thrips and blackspot.'Black Magic','Carola','Vendela','Rouge Meilland','Golden Emblem','Tineke','Movie Star' and 'Samantha' showed best comprehensive performance,which were thus worthy of large-scale popularization in Hainan Province. 展开更多
关键词 Tropical coastal area of China(Sanya) Rosa Hybrida cut roses INTRODUCTION Variety Selection
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Observation and Evaluation of New Lily Cutflower Varieties Introduced in Tropical Area 被引量:1
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作者 杨志娟 赵光英 +1 位作者 陈冠铭 李宏杨 《Agricultural Science & Technology》 CAS 2016年第2期309-312,共4页
[Objective] New lily varieties were introduced and selected to provide ref- erences for choosing lily varieties with the best comprehensive performance and most appropriate for tropical area. [Method] In winter, six l... [Objective] New lily varieties were introduced and selected to provide ref- erences for choosing lily varieties with the best comprehensive performance and most appropriate for tropical area. [Method] In winter, six lily cultivars including White Express, Concad'or, Aktiva, Donato, Star Fighter and Serano were planted outdoors in Hainan. Phenophase, morphological traits and cut flower quality of the tested cultivars were observed and compared in order to choose varieties suitable for Hainan. [Result] Their growth period ranged from 96 to 113 d with the mean of 105.3 d. Six cultivars had obvious differences in biological characteristics and cut- flower quality. Compared with the other 4 cultivars, Aktiva and Serano were superior for their bright color and beautiful shape, height uniformity, long florescence and strong growing. According to the comprehensive evaluation system of lily variety, the sequence was Serano 〉 Aktiva 〉 Concad'or 〉 Star Fighter 〉 Donato 〉 White Ex- press. [Conclusion] The two cultivars of Aktiva and Serano with good characters are selected for further research and extension in Sanya of Hainan. 展开更多
关键词 Tropical area Lily cut flower Introduction Cultivar screening
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Cutting performance of micro-textured PCBN tool 被引量:3
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作者 Lin Fan Zilong Deng +1 位作者 Xingjun Gao Yan He 《Nanotechnology and Precision Engineering》 CAS CSCD 2021年第2期25-32,共8页
To study the efect of micro-texture on the cutting performance of polyrystalline cubic boron nitide(PCBN)tools,five types of micro-textures(circular pits,eliptical grooves,transverse grooves,composite grooves,and wavy... To study the efect of micro-texture on the cutting performance of polyrystalline cubic boron nitide(PCBN)tools,five types of micro-textures(circular pits,eliptical grooves,transverse grooves,composite grooves,and wavy grooves)were applied to the rake surface of PCBN tools by an optical fber laser marking machine.Through a combination of three dimensional cutting simulations and experiments,the influences of micro-texture on chip-tool contact area,cutting force,chip morphology,shear angle,and surface roughness during the cuting process were analyzed.The results indicated that the chip--tool contact area and cutting force of both non-textured and micro textured tools increased with increasing cutting speed,while the shear angle decreased with increasing cutting speed.The chip-tool contact area and cutting force of the five types of micro-textured tools were smaller than those of the non textured tool The chip-tool contact area and cutting force obtained by the wavy-groove micro textured tool were the smallest.The chip radius produced by the five types of micro-textured tools was smaller than that produced by the non-textured tool,and the chip morphology was more stable.The transverse-groove micro-textured tool had a better chip breaking efect.The chip rnadius generated by the lliptical groove micro textured tool was 0.96 cm,while that generated by the wavy-groove tool varied from 0.55 cm to 1.26 cm.The presence of a micro-texture reduced the surface roughness of the workpiece by 11.73%-56.7%.Under the same cutting conditions,the five types of micro-textured tools gave a smaller chip--tool contact area,cutting force,chip radius,and surface roughness and a larger shear angle than the non-textured tool.In addition,the elliptical groove and wavy-groove micro-textured tools had better cuting performance. 展开更多
关键词 Micro-textured tool Chip tool contact area cutting force Chip radius
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Layer regrouping for water-flooded commingled reservoirs at a high water-cut stage 被引量:2
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作者 Chuan-Zhi Cui Jian-Peng Xu +3 位作者 Duan-Ping Wang Zhi-Hong Liu Ying-song Huang Zheng-Ling Geng 《Petroleum Science》 SCIE CAS CSCD 2016年第2期272-279,共8页
Layer regrouping is to divide all the layers into several sets of production series according to the physical properties and recovery percent of layers at high water-cut stage, which is an important technique to impro... Layer regrouping is to divide all the layers into several sets of production series according to the physical properties and recovery percent of layers at high water-cut stage, which is an important technique to improve oil recovery for high water-cut multilayered reservoirs. Dif- ferent regroup scenarios may lead to different production performances. Based on unstable oil-water flow theory, a multilayer commingled reservoir simulator is established by modifying the production split method. Taking into account the differences of layer properties, including per- meability, oil viscosity, and remaining oil saturation, the pseudo flow resistance contrast is proposed to serve as a characteristic index of layer regrouping for high water-cut multilayered reservoirs. The production indices of multi- layered reservoirs with different pseudo flow resistances are predicted with the established model in which the data are taken from the Shengtuo Oilfield. Simulation results show that the pseudo flow resistance contrast should be less than 4 when the layer regrouping is implemented. The K-means clustering method, which is based on the objec- tive function, is used to automatically carry out the layer regrouping process according to pseudo flow resistances. The research result is applied to the IV-VI sand groups of the second member of the Shahejie Formation in the Shengtuo Oilfield, a favorable development performance is obtained, and the oil recovery is enhanced by 6.08 %. 展开更多
关键词 Water-flooded reservoirs Layer regrouping.Flow resistance - High water cut Reservoir simulation
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Origin and depositional model of deep-water lacustrine sandstone deposits in the 7th and 6th members of the Yanchang Formation(Late Triassic),Binchang area,Ordos Basin,China 被引量:2
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作者 Xi-Xiang Liu Xiao-Qi Ding +1 位作者 Shao-Nan Zhang Hao He 《Petroleum Science》 SCIE CAS CSCD 2017年第1期24-36,共13页
Sandstones attributed to different lacustrine sediment gravity flows are present in the 7th and 6th members of the Yanchang Formation in the Ordos Basin, China. These differences in their origins led to different sand... Sandstones attributed to different lacustrine sediment gravity flows are present in the 7th and 6th members of the Yanchang Formation in the Ordos Basin, China. These differences in their origins led to different sandstone distributions which control the scale and connectivity of oil and gas reservoirs. Numerous cores and outcrops were analysed to understand the origins of these sandstones. The main origin of these sandstones was analysed by statistical methods, and well logging data were used to study their vertical and horizontal distributions. Results show that the sandstones in the study area accu- mulated via sandy debris flows, turbidity currents and slumping, and sandy debris flows predominate. The sand- stone associated with a single event is characteristically small in scale and exhibits poor lateral continuity. How- ever, as a result of multiple events that stacked gravity flow-related sandstones atop one another, sandstones are extensive overall, as illustrated in the cross section and isopach maps. Finally, a depositional model was developed in which sandy debris flows predominated and various other types of small-scale gravity flows occurred frequently, resulting in extensive deposition of sand bodies across a large area. 展开更多
关键词 Sediment gravity flows - Sandy debris flows -Binchang area Yanchang Formation Ordos Basin
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Genetic Relationship of the 1780-1760 Ma Dykes and the Coeval Volcanics in the Lvliang Area, North China 被引量:1
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作者 YANG Shuyan PENG Peng +2 位作者 Qin Zhaoyuan WANG Xinping WANG Chong 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第S1期133-134,共2页
The 1780-1760 Ma Taihang dyke swarm and the coeval Xiong’er volcanic province are the most widespread magmatic events occurring post the amalgamation of the two North China cratons.It has been debated whether
关键词 North China Genetic Relationship of the 1780-1760 Ma Dykes and the Coeval Volcanics in the Lvliang area PB
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Dynamic monitoring of menopause hormone therapy and defining the cut-off value of endometrial thickness during uterine bleeding 被引量:3
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作者 Qiu Sheng Jun Yang +1 位作者 Qiaoling Zhao Fen Li 《The Journal of Biomedical Research》 CAS CSCD 2016年第3期191-196,共6页
The aim of this study was to evaluate the effects of low-dose tibolone therapy on ovarian area, uterine volume and endometrial thickness, and define the cut-off value of endometrial thickness for curettage during uter... The aim of this study was to evaluate the effects of low-dose tibolone therapy on ovarian area, uterine volume and endometrial thickness, and define the cut-off value of endometrial thickness for curettage during uterine bleeding. We followed 619 postmenopausal women, aged 40-60 years, for two years. There were 301 subjects in the low-dose tibolone treatment group and 318 subjects in the control group. The ovarian area, uterine volume and endometrial thickness in all participants were measured by transvaginal ultrasound prior to, one and two years post enrollment, respectively. Endometrial specimens were collected from all subjects with abnormal uterine bleeding during the follow-up period. We found that the uterine volume in the treatment group was greater than that in the control group, and the difference was significant (P〈0.05), but there were no significant differences in ovarian area and endometrial thickness between the two groups (P〉0.05). When the cut-off value for endometrial thickness was 7.35 ram, the sensitivity and specificity were 100% and 79.07%, respectively, and 85.71% and 93.02% when 7.55 mm was set as the cut-offduring tibolone therapy. The results indicate that low-dose tibolone therapy may postpone uterine atrophy and the cut-off value of endometrial thickness may be appropriately adjusted for curettage. 展开更多
关键词 low-dose tibolone ovarian area uterine volume ENDOMETRIUM dynamic monitoring cut-off value
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Chronoframe of Archaean in Anshan-Benxi Area,Liaoning Province,China
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作者 Wan Yusheng Wu Jiashan Liu Dunyi Geng Yuansheng Song BiaoInstitute of Geology , Chinese Academy of Geological Sciences, Beijing 100037 《Journal of Earth Science》 SCIE CAS CSCD 1993年第1期35-40,共6页
The Anshan- Benxi area is one of the important places of the Precambrian in the North China craton, in which a lot of old geological bodies were found, including the Baijiafen mylontized granitic gneiss of 3.8 Ga ,the... The Anshan- Benxi area is one of the important places of the Precambrian in the North China craton, in which a lot of old geological bodies were found, including the Baijiafen mylontized granitic gneiss of 3.8 Ga ,the Chentaigou gneissic granite of 33 Ga and the supracrustal rocks and associated granites of relatively younger ages .Based on the age data and other geological information obtained in recent yeais, mis paper establishes fourfold-divison scheme of the Archaean in the Anshan-Benxi area .The time boundaries are 2.5,2.8,3.2 and 3.6 Ga, corresponding to those recommended by the International Sub-commission on Precambrian Stratigraphy . This paper also discusses some questions related to the crustal evolution of the early history, and indicates that it is possible to find out more residual crustal materials of older than 2.8 Ga. 展开更多
关键词 chronoframe of the Archaean - Anshan - Benxi area crustal evolution of the early history.
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Preliminary Study on Water Demand Law of 1-0 Rooted Cuttings of Populus szechuanica
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作者 Dabuqiong Haoyu WANG +2 位作者 Huanhuan XIE Zhen XING Yanhui YE 《Meteorological and Environmental Research》 CAS 2021年第4期39-42,共4页
In order to provide theoretical basis and technical support for the afforestation and artificial water supply of P.szechuanica in arid areas,the characteristics of water consumption of P.szechuanica were explored,and ... In order to provide theoretical basis and technical support for the afforestation and artificial water supply of P.szechuanica in arid areas,the characteristics of water consumption of P.szechuanica were explored,and the law of water demand of P.szechuanica was grasped.In this paper,potted seedlings of 1-0 rooted cuttings of P.szechuanica were taken as research objects,and change situation of water consumption under different water control gradients was measured regularly by using weighing method,further analyzing dynamic change of water consumption of P.szechuanica and revealing water demand law of 1-0 rooted cuttings of P.szechuanica.The results showed that total change of water consumption of 1-0 rooted cuttings of P.szechuanica had"slow-fast-slow-fast"double-peak trend in the growth period of the current year,and corresponded with univariate linear relation(R^(2)=0.7137),with significant difference.In whole growth period,water consumption in August was the highest,which was 2.7 times of that in June and July and 1.5 times of that after September.In different water control treatments,the dynamic changes of daily and monthly water consumption were significantly different.In seven water control treatments,monthly water consumption was between(6315.95±1690.70)and(10105.28±3065.30)g/month,and mean was(8211.07±2308.23)g/month.With intensification of water control treatment,water consumption increased,but there was no seedling death due to water shortage.P.szechuanica has great plasticity in water demand,and can survive in both arid and humid environments.Meanwhile,it is revealed that P.szechuanica is the most widely distributed tree species in the region. 展开更多
关键词 Populus szechuanica 1-0 rooted cuttings Water consumption Water demand law
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High efficient processing area of difficult-to-machine materials by using temperature-horsepower criterion
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作者 ANGELA S G ZHANG Dan SERGEY B V MARINA K A 《黑龙江科技大学学报》 CAS 2015年第4期386-393,共8页
关键词 俄语学习 外语学习 学习方法 俄语翻译
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The Test Area of Suizhong 36-1 Oil Field Fully Under Commission
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作者 Yan Hao 《China Oil & Gas》 CAS 1995年第3期14-14,共1页
TheTestAreaofSuizhong36-1OilFieldFullyUnderCommission¥//Suizhong36-lOilfieldlocatedin.LiaodongGulf,coveringa... TheTestAreaofSuizhong36-1OilFieldFullyUnderCommission¥//Suizhong36-lOilfieldlocatedin.LiaodongGulf,coveringanareaof48km2Theoi... 展开更多
关键词 TEST The Test area of Suizhong 36-1 Oil Field Fully Under Commission
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Pacific Area Standards Congress XXXI Held on April 22-23 in Shanghai
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《China Standardization》 2008年第3期3-3,共1页
关键词 Pacific area Standards Congress XXXI Held on April 22-23 in Shanghai
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基于Normalized Cut的图像分割改进算法 被引量:11
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作者 黄一岑 沈一帆 《计算机工程与应用》 CSCD 北大核心 2008年第34期179-181,187,共4页
用Normalized Cu(tN-Cut)准则分割图片时,会出现诸如过分割或者欠分割的不理想情况。在N-Cut结果的基础上提出了一种改进算法:利用合并-分裂方法,将颜色和纹理相似的区域合并,并对某些区域做进一步N-Cut分割。实验证明,改进后的算法不... 用Normalized Cu(tN-Cut)准则分割图片时,会出现诸如过分割或者欠分割的不理想情况。在N-Cut结果的基础上提出了一种改进算法:利用合并-分裂方法,将颜色和纹理相似的区域合并,并对某些区域做进一步N-Cut分割。实验证明,改进后的算法不仅保留了N-Cut方法的优点,而且从一定程度上解决了过分割和欠分割的缺点,能够处理一些自然界的彩色图片,得到了比较理想的分割结果。 展开更多
关键词 合并-分裂 N—cut准则 Texton
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湖北宜昌地区第四纪沉积物中锆石的U-Pb年龄特征及其物源意义 被引量:20
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作者 向芳 杨栋 +2 位作者 田馨 李志宏 罗来 《矿物岩石》 CAS CSCD 北大核心 2011年第2期106-114,共9页
对于长江三峡的贯通近年来基本认为是第四纪以来的事件,但在具体贯通时间的认识上仍存在差异。紧邻三峡出口、具有第四纪以来完整地层和较好出露层位的江汉盆地西缘宜昌地区的第四纪沉积物沉积特征及测年资料显示,该地区的云池组为冲积... 对于长江三峡的贯通近年来基本认为是第四纪以来的事件,但在具体贯通时间的认识上仍存在差异。紧邻三峡出口、具有第四纪以来完整地层和较好出露层位的江汉盆地西缘宜昌地区的第四纪沉积物沉积特征及测年资料显示,该地区的云池组为冲积扇—扇三角洲相沉积,善溪窑组下部为扇三角洲沉积,上部为湖相沉积。对云池组、善溪窑组、长江5级和4级阶地的015,024,YC02,00B剖面等4个典型剖面砾石层中砂质填隙物的锆石进行矿物学研究和LA-ICP-MS U-Pb年龄测定,发现015,024剖面中锆石主要来源于三峡以东的黄陵穹窿、武当地块,少量来自鄂陕边境的庙川地区和湘鄂交接的华容地区,均为三峡以东的物质来源。而长江第5,4级阶地沉积物中的锆石不仅存在上述三峡以东物源区的物质,同时出现三峡以西米仓山—大巴山地区、龙门山—攀枝花地区,以及川西巴塘—德格地区岩浆岩物源的物质,也具有来自峨眉山玄武岩的特征岩浆锆石的存在,从而证实了以015,024剖面为代表的沉积并非前人认为的长江阶地产物,同时也表明三峡的贯通应在024剖面沉积结束以后,YC02剖面沉积以前,即长江三峡贯通的时间应该在0.75 Ma以后。 展开更多
关键词 宜昌地区 锆石LA-ICP-MSU-Pb测年 物源分析 长江三峡贯通时间
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45淬硬钢干式切削刀-屑接触区域温度场分布研究 被引量:1
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作者 何志锋 唐德文 +2 位作者 谢宇鹏 李朋雪 周雄锋 《现代制造工程》 CSCD 北大核心 2017年第1期94-99,156,共7页
针对45淬硬钢干切削过程,考虑刀-屑接触区域热流密度不均匀性和热分配率不均匀性等因素,基于热源法建立前刀面刀-屑接触区域三维温度场解析模型,并利用验证试验和解析模型,研究前刀面刀-屑接触区域温度场分布规律。结果表明:模型预测值... 针对45淬硬钢干切削过程,考虑刀-屑接触区域热流密度不均匀性和热分配率不均匀性等因素,基于热源法建立前刀面刀-屑接触区域三维温度场解析模型,并利用验证试验和解析模型,研究前刀面刀-屑接触区域温度场分布规律。结果表明:模型预测值与实验值相吻合,两者误差低于3.26%;且前刀面刀-屑接触区域温度场分布呈均匀梯度分布;最高温度位置出现在刀-屑接触界面粘结摩擦区域结束处附近,最高温度位置受切削速度影响较小;最低温度位置出现在刀-屑接触界面边缘处。该模型具有较高准确度,对研制新型刀具、降低刀具磨损、提高加工效率和加工质量具有重要指导意义。 展开更多
关键词 干式切削 -屑接触区 温度场 解析建模
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橡胶树气刺短线采胶技术示范应用进展--以海南东方广坝地区为例 被引量:2
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作者 魏芳 莫东红 +6 位作者 刘超武 校现周 罗世巧 杨文凤 高宏华 仇键 吴明 《中国热带农业》 2021年第5期22-28,共7页
气刺短线采胶技术是1项省工高效的采胶技术,该项技术在我国海南、云南和广东三大植胶区进行了应用推广。本文对该技术在海南东方广坝地区的多年应用效果进行了总结,从技术使用单位的应用规模、干胶含量和胶工收入等方面进行统计和分析。... 气刺短线采胶技术是1项省工高效的采胶技术,该项技术在我国海南、云南和广东三大植胶区进行了应用推广。本文对该技术在海南东方广坝地区的多年应用效果进行了总结,从技术使用单位的应用规模、干胶含量和胶工收入等方面进行统计和分析。6年来该技术在广坝地区应用面积由2838亩增加到1.7万亩,应用单位由2014年的3个增加到2019年的11个,亩产平均增加8.3kg,年人均产量增加1.2吨(比常规割胶增加29.3%),年人均收入增加0.8万元(比常规割胶增加23.1%),6年共节约用工523人(比常规割胶减少42.9%)。分析表明:气刺短线采胶技术主要是通过增加人均割胶株数和提高人均产量提升了割胶劳动生产率,通过提高胶工收入稳定了胶工队伍,发挥了技术示范引领作用。 展开更多
关键词 气刺短线采胶技术 橡胶树 胶工短缺 广坝
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