According to the variable toe-to-heel well spacing, combined with the dislocation theory, discrete lattice method, and finite-element-method(FEM) based fluid-solid coupling, an integrated geological-engineering method...According to the variable toe-to-heel well spacing, combined with the dislocation theory, discrete lattice method, and finite-element-method(FEM) based fluid-solid coupling, an integrated geological-engineering method of volume fracturing for fan-shaped well pattern is proposed considering the geomechanical modeling, induced stress calculation, hydraulic fracturing simulation, and post-frac productivity evaluation. Besides, we propose the differential fracturing design for the conventional productivity-area and the potential production area for fan-shaped horizontal wells. After the fracturing of the conventional production area for H1 fan-shaped well platform, the research shows that the maximum reduction of the horizontal principal stress difference in the potential productivity-area is 0.2 MPa, which cannot cause the stress reversal, but this reduction is still conducive to the lateral propagation of hydraulic fractures. According to the optimized fracturing design, in zone-Ⅰ of the potential production area, only Well 2 is fractured, with a cluster spacing of 30 m and an injection rate of 12 m^(3)/min per stage;in zone-Ⅱ, Well 2 is fractured before Well 3, with a cluster spacing of 30 m and an injection rate of 12 m^(3)/min per stage. The swept area of the pore pressure drop in the potential production area is small, showing that the reservoir is not well developed. The hydraulic fracturing in the toe area can be improved by, for example, properly densifying the fractures and adjusting the fracture distribution, in order to enhance the swept volume and increase the reservoir utilization.展开更多
To improve the cooling performance, shape optimization of a laidback fan-shaped film cooling hole was performed. Three geometric parameters, including hole length, lateral expansion angle and forward expansion angle, ...To improve the cooling performance, shape optimization of a laidback fan-shaped film cooling hole was performed. Three geometric parameters, including hole length, lateral expansion angle and forward expansion angle, were selected as the design parameters. Numerical model of the film cooling system was established, validated, and used to generate 32 groups of training samples. Least square support vector machine(LS-SVM) was applied for surrogate model, and the optimal design parameters were determined by a kind of chaotic optimization algorithm. As hole length, lateral expansion angle and forward expansion angle are 90 mm, 20° and 5°, the area-averaged film cooling effectiveness can reach its maximum value in the design space. LS-SVM coupled with chaotic optimization algorithm is a promising scheme for the optimization of shaped film cooling holes.展开更多
当前各金融行业之间的联系日益密切,风险溢出进一步增强。在这一背景下,本文构建Vine-Copula模型,刻画银行业、保险业、基金业和证券业之间的风险相依关系,将上行广义Co Va R与下行广义Co Va R置于同一结构中,进一步研究当某一行业陷入...当前各金融行业之间的联系日益密切,风险溢出进一步增强。在这一背景下,本文构建Vine-Copula模型,刻画银行业、保险业、基金业和证券业之间的风险相依关系,将上行广义Co Va R与下行广义Co Va R置于同一结构中,进一步研究当某一行业陷入风险时对其他金融行业的风险溢出效应。实证结果显示,各金融行业均存在显著的正向风险溢出效应,上行风险溢出与下行风险溢出表现出非对称性。分行业而言,证券业对其他行业的风险溢出效应最强,银行业和基金业的风险溢出效应较为平稳,而保险业的风险溢出也处于较高水平,应当重点关注证券业与保险业之间的风险溢出效应。本文研究明晰了金融行业间的风险溢出效应,有助于对我国经济“三期叠加”阶段性特征进行科学理解与准确研判,为防范与化解重大金融风险提供参考依据。展开更多
Vine decline disease (VDD) constitutes a menace to melons worldwide. Especially, the one caused by the fungus Monosporascus cannonballus. Thus, resistant plant material must be released to help growers. Hence, our goa...Vine decline disease (VDD) constitutes a menace to melons worldwide. Especially, the one caused by the fungus Monosporascus cannonballus. Thus, resistant plant material must be released to help growers. Hence, our goal was to develop resistant plant material to VDD. More than 600 melon accessions are expected to be tested for disease resistance in M. cannonballus infested soil in Weslaco, Texas, USA, to identify resistance to VDD, and other important traits. So far, at most 7 lines were found to be resistant to VDD and some of them were used to develop elite, muskmelon inbred lines by pedigree breeding following single or double backcrosses. These elite parents were crossed to each other to develop the hybrids M3 and M4. They were also tested in the same infested field in Weslaco. The hybrids were grown using standard commercial practices followed by growers and when their fruits were ready, their roots were sampled as well as scored for disease severity to estimate high and mid-parent heterosis Our results indicate the existence of heterosis regarding resistance to VDD. Thus, resistant plant material can be developed and selection for resistance can be accomplished.展开更多
可再生能源参与电力现货市场政策制定前,需度量可再生能源的市场风险。在可再生能源未深度参与电力现货背景下,直接采用传统方法对历史数据进行风险度量不可行。文章结合可再生能源有效出力和在险模型(Value at Risk,VaR)设计了可再生...可再生能源参与电力现货市场政策制定前,需度量可再生能源的市场风险。在可再生能源未深度参与电力现货背景下,直接采用传统方法对历史数据进行风险度量不可行。文章结合可再生能源有效出力和在险模型(Value at Risk,VaR)设计了可再生能源风险度量指标,通过风险场景匹配市场和机组出力数据。针对目前国内电力现货市场数据量少的问题,结合市场主体在电力现货市场中所能获得的数据进行市场因子筛选,通过Vine-Copula函数考虑多个市场因子间的相关性;改进了传统蒙特卡罗法收敛慢的缺陷,采用拟蒙特卡罗模拟法生成市场因子数据,根据拟合的映射关系生成电价水平数据。最后,文章基于南方(以广东起步)电力现货市场结算试运行的数据和海上风电与光伏的仿真出力,对所提出的模型进行算例分析,结果显示拟蒙特卡罗法收敛性更高,能满足模型中所有风险场景高频计算风险的需求。展开更多
The study aimed to evaluate the application of silage fermentation in storing vine tea residue.Dynamic of fermentationrelated product,chemical component and bacterial community of silage with or without Lactobacillus ...The study aimed to evaluate the application of silage fermentation in storing vine tea residue.Dynamic of fermentationrelated product,chemical component and bacterial community of silage with or without Lactobacillus plantarum F1inoculant were analyzed.The results showed that F1 treatment had a significant (P<0.05) impact on the lactic acid and ammoniacal nitrogen concentrations and pH value.Total phenols were well preserved in both treatments.After 30 days of ensiling,L.plantarum occupied the majority of Lactobacillus genus (more than 95%) in all silage samples.Spearman revealed a positive (P<0.01) correlation between lactic acid content and Lactobacillus.Overall,ensiling vine tea residue with L.plantarum can effectively preserve the nutritional attributes and total phenols,which offers a new insight into utilizing vine tea residue.展开更多
This paper expounded the current situation and genetic mechanisms of short-vine watermelon breeding from the aspects of material sources,breeding process and genetic characteristics of F_1,hoping to provide a theoreti...This paper expounded the current situation and genetic mechanisms of short-vine watermelon breeding from the aspects of material sources,breeding process and genetic characteristics of F_1,hoping to provide a theoretical basis for short-vine watermelon breeding,and breeding materials for watermelon planting innovation,as well as new opportunities for high-quality and high-yield watermelon.展开更多
基金Supported by National Natural Science Foundation of China (52104029,U2139204)PetroChina Science and Technology Innovation Foundation (2021 DQ02-0501)。
文摘According to the variable toe-to-heel well spacing, combined with the dislocation theory, discrete lattice method, and finite-element-method(FEM) based fluid-solid coupling, an integrated geological-engineering method of volume fracturing for fan-shaped well pattern is proposed considering the geomechanical modeling, induced stress calculation, hydraulic fracturing simulation, and post-frac productivity evaluation. Besides, we propose the differential fracturing design for the conventional productivity-area and the potential production area for fan-shaped horizontal wells. After the fracturing of the conventional production area for H1 fan-shaped well platform, the research shows that the maximum reduction of the horizontal principal stress difference in the potential productivity-area is 0.2 MPa, which cannot cause the stress reversal, but this reduction is still conducive to the lateral propagation of hydraulic fractures. According to the optimized fracturing design, in zone-Ⅰ of the potential production area, only Well 2 is fractured, with a cluster spacing of 30 m and an injection rate of 12 m^(3)/min per stage;in zone-Ⅱ, Well 2 is fractured before Well 3, with a cluster spacing of 30 m and an injection rate of 12 m^(3)/min per stage. The swept area of the pore pressure drop in the potential production area is small, showing that the reservoir is not well developed. The hydraulic fracturing in the toe area can be improved by, for example, properly densifying the fractures and adjusting the fracture distribution, in order to enhance the swept volume and increase the reservoir utilization.
基金Project(U1508212)supported by the National Natural Science Foundation of ChinaProject(2015M570448)supported by the Postdoctoral Science Foundation of China
文摘To improve the cooling performance, shape optimization of a laidback fan-shaped film cooling hole was performed. Three geometric parameters, including hole length, lateral expansion angle and forward expansion angle, were selected as the design parameters. Numerical model of the film cooling system was established, validated, and used to generate 32 groups of training samples. Least square support vector machine(LS-SVM) was applied for surrogate model, and the optimal design parameters were determined by a kind of chaotic optimization algorithm. As hole length, lateral expansion angle and forward expansion angle are 90 mm, 20° and 5°, the area-averaged film cooling effectiveness can reach its maximum value in the design space. LS-SVM coupled with chaotic optimization algorithm is a promising scheme for the optimization of shaped film cooling holes.
文摘当前各金融行业之间的联系日益密切,风险溢出进一步增强。在这一背景下,本文构建Vine-Copula模型,刻画银行业、保险业、基金业和证券业之间的风险相依关系,将上行广义Co Va R与下行广义Co Va R置于同一结构中,进一步研究当某一行业陷入风险时对其他金融行业的风险溢出效应。实证结果显示,各金融行业均存在显著的正向风险溢出效应,上行风险溢出与下行风险溢出表现出非对称性。分行业而言,证券业对其他行业的风险溢出效应最强,银行业和基金业的风险溢出效应较为平稳,而保险业的风险溢出也处于较高水平,应当重点关注证券业与保险业之间的风险溢出效应。本文研究明晰了金融行业间的风险溢出效应,有助于对我国经济“三期叠加”阶段性特征进行科学理解与准确研判,为防范与化解重大金融风险提供参考依据。
文摘Vine decline disease (VDD) constitutes a menace to melons worldwide. Especially, the one caused by the fungus Monosporascus cannonballus. Thus, resistant plant material must be released to help growers. Hence, our goal was to develop resistant plant material to VDD. More than 600 melon accessions are expected to be tested for disease resistance in M. cannonballus infested soil in Weslaco, Texas, USA, to identify resistance to VDD, and other important traits. So far, at most 7 lines were found to be resistant to VDD and some of them were used to develop elite, muskmelon inbred lines by pedigree breeding following single or double backcrosses. These elite parents were crossed to each other to develop the hybrids M3 and M4. They were also tested in the same infested field in Weslaco. The hybrids were grown using standard commercial practices followed by growers and when their fruits were ready, their roots were sampled as well as scored for disease severity to estimate high and mid-parent heterosis Our results indicate the existence of heterosis regarding resistance to VDD. Thus, resistant plant material can be developed and selection for resistance can be accomplished.
文摘可再生能源参与电力现货市场政策制定前,需度量可再生能源的市场风险。在可再生能源未深度参与电力现货背景下,直接采用传统方法对历史数据进行风险度量不可行。文章结合可再生能源有效出力和在险模型(Value at Risk,VaR)设计了可再生能源风险度量指标,通过风险场景匹配市场和机组出力数据。针对目前国内电力现货市场数据量少的问题,结合市场主体在电力现货市场中所能获得的数据进行市场因子筛选,通过Vine-Copula函数考虑多个市场因子间的相关性;改进了传统蒙特卡罗法收敛慢的缺陷,采用拟蒙特卡罗模拟法生成市场因子数据,根据拟合的映射关系生成电价水平数据。最后,文章基于南方(以广东起步)电力现货市场结算试运行的数据和海上风电与光伏的仿真出力,对所提出的模型进行算例分析,结果显示拟蒙特卡罗法收敛性更高,能满足模型中所有风险场景高频计算风险的需求。
基金supported by the National Natural Science Foundation of China (32001402 and 32171686)。
文摘The study aimed to evaluate the application of silage fermentation in storing vine tea residue.Dynamic of fermentationrelated product,chemical component and bacterial community of silage with or without Lactobacillus plantarum F1inoculant were analyzed.The results showed that F1 treatment had a significant (P<0.05) impact on the lactic acid and ammoniacal nitrogen concentrations and pH value.Total phenols were well preserved in both treatments.After 30 days of ensiling,L.plantarum occupied the majority of Lactobacillus genus (more than 95%) in all silage samples.Spearman revealed a positive (P<0.01) correlation between lactic acid content and Lactobacillus.Overall,ensiling vine tea residue with L.plantarum can effectively preserve the nutritional attributes and total phenols,which offers a new insight into utilizing vine tea residue.
文摘This paper expounded the current situation and genetic mechanisms of short-vine watermelon breeding from the aspects of material sources,breeding process and genetic characteristics of F_1,hoping to provide a theoretical basis for short-vine watermelon breeding,and breeding materials for watermelon planting innovation,as well as new opportunities for high-quality and high-yield watermelon.
