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A Hybrid Level Set Optimization Design Method of Functionally Graded Cellular Structures Considering Connectivity
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作者 Yan Dong Kang Zhao +1 位作者 Liang Gao Hao Li 《Computers, Materials & Continua》 SCIE EI 2024年第4期1-18,共18页
With the continuous advancement in topology optimization and additive manufacturing(AM)technology,the capability to fabricate functionally graded materials and intricate cellular structures with spatially varying micr... With the continuous advancement in topology optimization and additive manufacturing(AM)technology,the capability to fabricate functionally graded materials and intricate cellular structures with spatially varying microstructures has grown significantly.However,a critical challenge is encountered in the design of these structures–the absence of robust interface connections between adjacent microstructures,potentially resulting in diminished efficiency or macroscopic failure.A Hybrid Level Set Method(HLSM)is proposed,specifically designed to enhance connectivity among non-uniform microstructures,contributing to the design of functionally graded cellular structures.The HLSM introduces a pioneering algorithm for effectively blending heterogeneous microstructure interfaces.Initially,an interpolation algorithm is presented to construct transition microstructures seamlessly connected on both sides.Subsequently,the algorithm enables the morphing of non-uniform unit cells to seamlessly adapt to interconnected adjacent microstructures.The method,seamlessly integrated into a multi-scale topology optimization framework using the level set method,exhibits its efficacy through numerical examples,showcasing its prowess in optimizing 2D and 3D functionally graded materials(FGM)and multi-scale topology optimization.In essence,the pressing issue of interface connections in complex structure design is not only addressed but also a robust methodology is introduced,substantiated by numerical evidence,advancing optimization capabilities in the realm of functionally graded materials and cellular structures. 展开更多
关键词 Hybrid level set method functionally graded cellular structure CONNECTIVITY interpolated transition optimization design
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Concurrent Two-Scale Topology Optimization of Thermoelastic Structures Using a M-VCUT Level Set Based Model of Microstructures
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作者 Jin Zhou Minjie Shao +1 位作者 Ye Tian Qi Xia 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第11期1327-1345,共19页
By analyzing the results of compliance minimization of thermoelastic structures,we observed that microstructures play an important role in this optimization problem.Then,we propose to use a multiple variable cutting(M... By analyzing the results of compliance minimization of thermoelastic structures,we observed that microstructures play an important role in this optimization problem.Then,we propose to use a multiple variable cutting(M-VCUT)level set-based model of microstructures to solve the concurrent two-scale topology optimization of thermoelastic structures.A microstructure is obtained by combining multiple virtual microstructures that are derived respectively from multiple microstructure prototypes,thus giving more diversity of microstructure and more flexibility in design optimization.The effective mechanical properties of microstructures are computed in an off-line phase by using the homogenization method,and then a mapping relationship between the design variables and the effective properties is established,which gives a data-driven model of microstructure.In the online phase,the data-driven model is used in the finite element analysis to improve the computational efficiency.The compliance minimization problem is considered,and the results of numerical examples prove that the proposed method is effective. 展开更多
关键词 Two-scale structure topology optimization multiple variable cutting level set DATA-DRIVEN radial basis function thermoelastic structure
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Surface and Content Validity of the Mentoring Function Scale for Novice Nurses
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作者 Aimi Furukawa Yasuko Hosoda 《Open Journal of Nursing》 2024年第8期401-411,共11页
This study aimed to examine the surface and content validity of the Mentoring Function Scale for Novice Nurses, used to assess the mentoring of entry-level nurses, and to refine the scale items. In Study 1, six nurse ... This study aimed to examine the surface and content validity of the Mentoring Function Scale for Novice Nurses, used to assess the mentoring of entry-level nurses, and to refine the scale items. In Study 1, six nurse education researchers, selected using convenience sampling, with five or more years of nursing experience and experience teaching novice nurses, were invited to an expert meeting in July 2015. A group interview was conducted that lasted approximately 120 minutes. Study 2 examined the content validity index. Between September and November 2015, we distributed a self-administered questionnaire survey to 11 participants selected by convenience sampling. The participants included five nurse education researchers with a minimum of five years of nursing experience and experience teaching novice nurses, as well as six clinical nurses with a master’s degree or higher. Finally, 81 questionnaire items were retained from the initial 125 items. The 81-item Mentoring Function Scale for Novice Nurses had higher content validity than the original scale. To further increase the scale’s applicability, future studies should assess its reliability, construct validity, and criterion-related validity. 展开更多
关键词 Novice Nurses Mentoring function Surface and Content Validity Item-level Content Validity Index
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Calculation of microscopic nuclear level densities based on covariant density functional theory 被引量:3
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作者 Kun-Peng Geng Peng-Xiang Du +1 位作者 Jian Li Dong-Liang Fang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第9期118-127,共10页
In this study,a microscopic method for calculating the nuclear level density(NLD)based on the covariant density functional theory(CDFT)is developed.The particle-hole state density is calculated by a combinatorial meth... In this study,a microscopic method for calculating the nuclear level density(NLD)based on the covariant density functional theory(CDFT)is developed.The particle-hole state density is calculated by a combinatorial method using single-particle level schemes obtained from the CDFT,and the level densities are then obtained by considering collective effects such as vibration and rotation.Our results are compared with those of other NLD models,including phenomenological,microstatisti-cal and nonrelativistic Hartree–Fock–Bogoliubov combinatorial models.This comparison suggests that the general trends among these models are essentially the same,except for some deviations among the different NLD models.In addition,the NLDs obtained using the CDFT combinatorial method with normalization are compared with experimental data,including the observed cumulative number of levels at low excitation energies and the measured NLDs.The CDFT combinatorial method yields results that are in reasonable agreement with the existing experimental data. 展开更多
关键词 Nuclear level density Covariant density functional theory Combinatorial method
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Nonlinear change of ion-induced secondary electron emission in theκ-Al_(2)O_(3) surface charging from first-principle modelling
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作者 Zhicheng JIAO Mingrui ZHU +2 位作者 Dong DAI Tao SHAO Buang WANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第9期40-50,共11页
Secondary electron emission(SEE)induced by the positive ion is an essential physical process to influence the dynamics of gas discharge which relies on the specific surface material.Surface charging has a significant ... Secondary electron emission(SEE)induced by the positive ion is an essential physical process to influence the dynamics of gas discharge which relies on the specific surface material.Surface charging has a significant impact on the material properties,thereby affecting the SEE in the plasma-surface interactions.However,it does not attract enough attention in the previous studies.In this paper,SEE dependent on the charged surface of specific materials is described with the computational method combining a density functional theory(DFT)model from the first-principle theory and the theory of Auger neutralization.The effect ofκ-Al2O3 surface charge,as an example,on the ion-induced secondary electron emission coefficient(SEEC)is investigated by analyzing the defect energy level and band structure on the charged surface.Simulation results indicate that,with the surface charge from negative to positive,the SEEC of a part of low ionization energy ions(such as Ei=12.6 eV)increases first and then decreases,exhibiting a nonlinear changing trend.This is quite different from the monotonic decreasing tendency observed in the previous model which simplifies the electronic structure.This irregular increase of the SEEC can be attributed to the lower escaped probability of orbital energy.The results further illustrate that the excessive charge could cause the bottom of the conduction band close to the valence band,thus leading to the decrease of the orbital energy occupied by the excited electrons.The nonlinear change of SEEC demonstrates a more realistic situation of how the electronic structure of material surface influences the SEE process.This work provides an accurate method of calculating SEEC from specific materials,which is urgent in widespread physical scenarios sensitive to surface materials,such as increasingly growing practical applications concerning plasma-surface interactions. 展开更多
关键词 secondary electron emission charged surface density functional theory defect energy level
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Study on the Functional Division of Agricultural Sightseeing in Handan City
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作者 张东云 郭建华 《Journal of Landscape Research》 2010年第3期52-54,共3页
Agricultural sightseeing in a new tourism pattern integrates ecological tourism functions into ecological agriculture and rural cultures. Handan City is located in southern Henan Province with excellent geographical c... Agricultural sightseeing in a new tourism pattern integrates ecological tourism functions into ecological agriculture and rural cultures. Handan City is located in southern Henan Province with excellent geographical conditions. In 2006-2008, agricultural sightseeing has achieved primary development in Handan City, and gradually become an indispensable component of the tourism market in this city. Promoting agricultural sightseeing in Handan City as well as the upgrading of its agriculture will be enhanced, which can be transformed from traditional and unitary function into the comprehensive functions of production, ecology, tourism, culture and education, thus is favorable for promoting the further development of tourism industry, enriching tourism products, realizing the sustainable development of agricultural tourism. Besides, surplus rural labors will be offered more opportunities, and industrial structure in rural areas will also be adjusted properly. Through dividing agricultural sightseeing in Handan City into the eco-agricultural sightseeing zone in the west, metropolis agricultural sightseeing zone in the middle, and economic agricultural sightseeing in the east, the authors clearly defined their ranges, orientation of typical functions, dominant development modes as well as projects, so as to figure out the reasonable development pattern for agricultural sightseeing in Handan City, specify its development context, and provide theoretical basis for the future development of agricultural sightseeing in this city. 展开更多
关键词 Handan City Agricultural sightseeing functional division
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Reflections on,and Improvements of,the Mediation Functions of People's Assessors
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作者 Wang Gali 《Contemporary Social Sciences》 2023年第6期20-32,共13页
Legislatively,the people’s assessors are defined as individuals who share judicial power.However,in the context of dispute resolutions,their role is restricted by the courts,which affects the extent of their assessor... Legislatively,the people’s assessors are defined as individuals who share judicial power.However,in the context of dispute resolutions,their role is restricted by the courts,which affects the extent of their assessorial activities.It is imperative to reconsider the implications of the people’s assessors’deep involvement in mediation from the standpoint of societal division of labor.To enhance this division of labor,it is advisable that the people’s assessors relinquish their mediation roles.It is necessary to redefine the distinctions between people’s assessors,judges,and people’s mediators,including specially invited mediators.This would not only make up the deficiencies in the role of professional judges but also relieve the tension between judicial professionalism and popular accountability. 展开更多
关键词 social division of labor assessor system mediation function REFLECTION improvement
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基于REOF的两种卫星降水产品(IMERG和MSWEP)在金沙江流域降水分区尺度精度评估
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作者 薄会娟 林青霞 +2 位作者 李璐 魏冲 龚成麒 《湖泊科学》 EI CAS CSCD 北大核心 2024年第2期620-633,共14页
高时空分辨率降水产品的精度评估是卫星降水用于水文气象干旱等研究的前提。本研究提出在降水分区尺度下评估IMERG和MSWEP两种卫星降水产品的精度,并与不分区尺度(即流域尺度)进行比较。首先采用旋转经验正交函数(REOF)对金沙江流域(JSB... 高时空分辨率降水产品的精度评估是卫星降水用于水文气象干旱等研究的前提。本研究提出在降水分区尺度下评估IMERG和MSWEP两种卫星降水产品的精度,并与不分区尺度(即流域尺度)进行比较。首先采用旋转经验正交函数(REOF)对金沙江流域(JSB)进行降水分区,通过贡献率得出8个分区较为适合。然后识别降水的空间分布特征,发现2种降水产品都可以很好地捕捉降水呈现出的从上游到下游逐渐增加的趋势。最后在日尺度、降水发生概率和极端降水探测能力3个方面对降水产品在分区尺度和不分区尺度的性能进行评估。结果表明,在日尺度上,MSWEP的精度在多数降水分区优于IMERG,被推荐5次(1、3、6、7和8区),集中在流域的中游。同时流域尺度也推荐MSWEP。在降水事件发生概率方面,MSWEP能再现不同等级降水强度的概率密度分布,但过高估计0.1~1 mm/d降水事件的发生概率;而IMERG过高估计小于0.1 mm/d降水事件的概率。在极端降水探测能力方面,流域尺度的KGE值都是正值,且IMERG优于MSWEP,但分区尺度上,KGE值在部分降水分区中存在负值,表明IMERG和MSWEP均不能很好地探测出该区的极端降水事件。本研究成果表明降水分区尺度是必需的,能够更加精细地评估降水产品。研究结果可为具有类似气候条件的卫星降水评估提供参考。 展开更多
关键词 降水分区 旋转经验正交函数 IMERG MSWEP 精度评估
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Dietary energy sources and levels shift the multi-kingdom microbiota and functions in the rumen of lactating dairy cows 被引量:6
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作者 Tansol Park Lu Ma +3 位作者 Ying Ma Xiaoqiao Zhou Dengpan Bu Zhongtang Yu 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2020年第4期1073-1088,共16页
Background: Dietary energy source and level in lactation diets can profoundly affect milk yield and composition.Such dietary effects on lactation performance are underpinned by alteration of the rumen microbiota, of w... Background: Dietary energy source and level in lactation diets can profoundly affect milk yield and composition.Such dietary effects on lactation performance are underpinned by alteration of the rumen microbiota, of which bacteria, archaea, fungi, and protozoa may vary differently. However, few studies have examined all the four groups of rumen microbes. This study investigated the effect of both the level and source of dietary energy on rumen bacteria, archaea, fungi, and protozoa in the rumen of lactating dairy cows. A 2 × 2 factorial design resulted in four dietary treatments: low and high dietary energy levels(LE: 1.52–1.53;and HE: 1.71–1.72 Mcal/kg dry matter) and two dietary energy sources(GC: finely ground corn;and SFC: steam-flaked corn). We used a replicated 4 × 4 Latin square design using eight primiparous Chinese Holstein cows with each period lasting for 21 d. The rumen microbiota was analyzed using metataxonomics based on kingdom-specific phylogenetic markers [16 S r RNA gene for bacteria and archaea, 18 S r RNA gene for protozoa, and internally transcribed spacer 1(ITS1) for fungi] followed with subsequent functional prediction using PICRUSt2.Results: The GC resulted in a higher prokaryotic(bacterial and archaeal) species richness and Faith's phylogenetic diversity than SFC. For the eukaryotic(fungi and protozoa) microbiota, the LE diets led to significantly higher values of the above measurements than the HE diets. Among the major classified taxa, 23 genera across all the kingdoms differed in relative abundance between the two dietary energy levels, while only six genera(none being protozoal)were differentially abundant between the two energy sources. Based on prokaryotic amplicon sequence variants(ASVs) from all the samples, overall functional profiles predicted using PICRUSt2 differed significantly between LE and HE but not between the two energy sources. Fish Taco analysis identified Ruminococcus and Coprococcus as the taxa potentially contributing to the enriched KEGG pathways for biosynthesis of amino acids and to the metabolisms of pyruvate, glycerophospholipid, and nicotinate and nicotinamide in the rumen of HE-fed cows. The co-occurrence networks were also affected by the dietary treatments, especially the LE and GC diets, resulting in distinct co-occurrence networks. Several microbial genera appeared to be strongly correlated with one or more lactation traits.Conclusions: Dietary energy level affected the overall rumen multi-kingdom microbiota while little difference was noted between ground corn and steam-flaked corn. Some genera were also affected differently by the four dietary treatments, including genera that had been shown to be correlated with lactation performance or feed efficiency.The co-occurrence patterns among the genera exclusively found for each dietary treatment may suggest possible metabolic interactions specifically affected by the dietary treatment. Some of the major taxa were positively correlated to milk properties and may potentially serve as biomarkers of one or more lactation traits. 展开更多
关键词 Corn processing method Dietary energy level functional profiles Multi-kingdom Rumen microbiota
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Method and Practice on Water Function Division of the Yangtze River Region 被引量:1
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作者 YUAN Hong-renProfessor-senior Engineer, Yangtze Valley Water Resources Protection Bureau, Wuhan 430051, China LUO Xiao-yongSenior Engineer, Yangtze Valley Water Resources Protection Bureau, Wuhan 430051, China 《人民长江》 北大核心 2002年第S1期54-57,共4页
Water function classification is to divide the waters in a basin or a region into different water function regions according to the natural features such as water resources condition, physical geographical location, e... Water function classification is to divide the waters in a basin or a region into different water function regions according to the natural features such as water resources condition, physical geographical location, environmental condition, etc. and social features such as the status quo of development and utilization, the requirement of social and economic development on water quantity and quality etc. Water function division has not ever been carried out in China and no ready-made theory and method can be complied with, in the meantime, it is a fundamental work with strong practical function. Therefore, the basic concept and theory foundation and research method are put forward on the base of summary of water resources management and developed and will be perfected in practice process of water function division. The Yangtze function zone covers the Yangtze river basin, the Lancang river basin and the rivers in the western area of the Lancang river in Southwest China. According to the technical outline of national water function division and combined with division practice of the Yangtze function zone, this paper presents the scope determination, procedure and method of water function division. 展开更多
关键词 WATER function division procedure METHOD scope YANGTZE river
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GDS-MIMO-OFDM雷达通信一体化波形设计
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作者 赵忠凯 闫秋贞 《舰船电子对抗》 2024年第1期1-8,71,共9页
针对正交频分复用(OFDM)雷达通信一体化波形存在的通信速率较低、自相关旁瓣较高的问题,提出了一种基于Gold码扩频的多输入多输出-正交频分复用(MIMO-OFDM)雷达通信一体化波形。将MIMO-OFDM与扩频序列相结合,利用相关性较好的Gold码对... 针对正交频分复用(OFDM)雷达通信一体化波形存在的通信速率较低、自相关旁瓣较高的问题,提出了一种基于Gold码扩频的多输入多输出-正交频分复用(MIMO-OFDM)雷达通信一体化波形。将MIMO-OFDM与扩频序列相结合,利用相关性较好的Gold码对通信信息进行扩频,再与OFDM脉冲符号进行调制,进而设计出一种既能提高通信速率又能改善雷达性能的一体化波形。仿真实验证明,较相同仿真条件下的Gold-OFDM、脉冲压缩-正交频分复用(PC-OFDM)一体化波形而言,所设计的一体化波形的通信速率能够倍数提高且可以在不影响通信性能的前提下降低信号模糊函数的旁瓣,从而改善一体化系统的雷达性能。 展开更多
关键词 雷达通信一体化 多输入多输出-正交频分复用雷达 模糊函数 扩频
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Investigation of analytical harmonic frequency and potential energy function, vibrational levels for the X^2∑^+ and A^2Л states of CN radical
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作者 Wang Jian-Kun Wu Zhen-Sen 《Chinese Physics B》 SCIE EI CAS CSCD 2008年第8期2919-2924,共6页
This paper calculates the equilibrium structure and the potential energy functions of the ground state (X^2∑^+) and the low lying excited electronic state (A^2Л) of CN radical are calculated by using CASSCF met... This paper calculates the equilibrium structure and the potential energy functions of the ground state (X^2∑^+) and the low lying excited electronic state (A^2Л) of CN radical are calculated by using CASSCF method. The potential energy curves are obtained by a least square fitting to the modified Murrell-Sorbie function. On the basis of physical theory of potential energy function, harmonic frequency (ωe) and other spectroscopic constants (ωeχe, βe and αe) are calculated by employing the Rydberg-Klei-Rees method. The theoretical calculation results are in excellent agreement with the experimental and other complicated theoretical calculation data. In addition, the eigenvalues of vibrational levels have been calculated by solving the radial one-dimensional SchrSdinger equation of nuclear motion using the algebraic method based on the analytical potential energy function. 展开更多
关键词 potential energy function harmonic frequency vibrational levels algebraic method
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Advance in Functional Restoration of Injured Nerve with Low Level Laser and its Utilization in the Dental and Maxillofacial Region
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作者 Pugen An Jizhi Zhao 《Chinese Medical Sciences Journal》 CAS CSCD 2020年第3期272-277,共6页
The inferior alveolar nerve and facial nerve are the two most important nerves in the dental and maxillofacial region.The injury to them is one of the major postoperative complications after alveolar surgery and ortho... The inferior alveolar nerve and facial nerve are the two most important nerves in the dental and maxillofacial region.The injury to them is one of the major postoperative complications after alveolar surgery and orthognathic surgery.However,recovering the nerve function after injury takes a long time and the recovery effect tends to be unsatisfactory.In recent years,an intensively investigated technique,low level laser which has been applying in assisting the recovery of nerve function,has been gradually proved to be effective in clinically treating postoperative nerve injury.In this article we review in terms of the mechanisms involved in low level laser-assisted functional restoration of nerve injury and its clinical application in the recovery of nerve function in the dental and maxillofacial area as well. 展开更多
关键词 low level laser nerve injury functional restoration dental and maxillofacial surgery
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The Single Valley Character of Level Degree Function
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作者 傅增明 佟晓石 《Journal of Donghua University(English Edition)》 EI CAS 2004年第4期153-155,共3页
Strict proof has been given to single valley character of level degree function by use of convex analysis theory, which provides reliable theoretical basis for the optimization of the data processing with respect to l... Strict proof has been given to single valley character of level degree function by use of convex analysis theory, which provides reliable theoretical basis for the optimization of the data processing with respect to level degree. As circle degree and cylindrical degree have the same mathematical structures, their single valley character can be proved by the same method. 展开更多
关键词 Convex Analysis theory level Degree function Single Valley Character.
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Study on the Occurrence and Epidemic Regularity and Region Division of Rice Blast in Nanchong City 被引量:1
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作者 彭昌家 白体坤 +2 位作者 丁攀 冯礼斌 杨宇衡 《Agricultural Science & Technology》 CAS 2016年第4期927-937,共11页
With the aim to improve the level of monitoring and warning as well as the comprehensive control of rice blast disease, and to feasibly reduce the disease threat in Nanchong City, the methods of GPS and GIS, systemati... With the aim to improve the level of monitoring and warning as well as the comprehensive control of rice blast disease, and to feasibly reduce the disease threat in Nanchong City, the methods of GPS and GIS, systematical monitoring and field survey, rice blast resistance identification, physiologic races of rice blast monitoring, and meteorological data analysis were performed to study the occurrence and epidemic region division, precise demarcation and occurrence and epidemic regularity of rice blast in Nanchong City. This study first completed the epidemic region division and precise demarcation; first clarified the initial affection(beginning period) locations, occurrence characteristics, epidemic trends and characteristics; explicated the existence of four epidemic peak periods of rice blast in the field, where the damage areas of first peak period played a decisive role during the blast epidemic years; in late May, the cumulative occurrence areas and annual occurrence areas presented higher positive correlation with the correlation coefficient of 0.817;and established a prediction model of occurrence areas per year based on the disease field rate at the end of boot stages and the diseased plant rate at dough stages. The results of investigation on the impact factors investigation of blast disease in Nanchong in recent years suggested that the internal causes were the decrease or loss of blast resistance of the rice cultivars, as well as the increase of physiological races with strong resistance to rice blast and the emergence of new virulent physiologic varieties; the external causes were suitable temperature, too much rainy, and sunlight shortage. Between 2010 and 2015, the short-term forecast accuracy for rice blast in Nanchong was up to 100%, and medium-and long-term forecast accuracy was also up to 98% and 95%, respectively, which increased by 5-15% than that before 1997, thereby making the control effect of rice blast in Nanchong increased by 15-30%. 展开更多
关键词 Rice Rice blast Region division Occurrence characteristics Epidemic regularity Early warning level
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基于EOF-DBSCAN-GRU的分布式光伏集群出力预测方法研究 被引量:1
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作者 麻吕斌 潘国兵 +3 位作者 蒋群 郭鹏 吴春华 赵宇航 《太阳能学报》 EI CAS CSCD 北大核心 2024年第1期39-46,共8页
提出一种基于EOF-DBSCAN划分集群的改进统计升尺度的光伏集群出力预测建模方法。针对传统统计升尺度方法子集群中光伏电站出力特性不一致问题,通过皮尔逊相关系数和经验正交函数(EOF)优化特征空间,再根据密度聚类模型(DBSCAN)对区域内... 提出一种基于EOF-DBSCAN划分集群的改进统计升尺度的光伏集群出力预测建模方法。针对传统统计升尺度方法子集群中光伏电站出力特性不一致问题,通过皮尔逊相关系数和经验正交函数(EOF)优化特征空间,再根据密度聚类模型(DBSCAN)对区域内光伏电站划分集群,从而增强光伏电站聚类后集群出力特性的一致性。针对待预测日权重系数时间序列动态特性的提取、预测问题,提出一种基于动态时间规整(DTW)的相似日选取算法。最后利用循环神经网络(GRU)模型进行光伏电站出力预测。实验表明该集群预测方法的平均误差百分数(MAPE)约为6.33%,均方根误差(RMSE)约为13.93 kW,均方误差(MSE)为194.25 kW,通过实际光伏电站数据证明了所提方法的准确性和有效性。 展开更多
关键词 分布式光伏电站 集群划分 经验正交函数 DBSCAN聚类算法 动态时间规整
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Spatial and Temporal Differences of Climate Suitability of Ice and Snow Sports in Major Ski Tourism Destinations in China
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作者 XIE Xia PANG Zhengjin +2 位作者 ZHU Haiqiang GAO Jun ZHOU Qiaoya 《Chinese Geographical Science》 SCIE CSCD 2024年第5期967-982,共16页
Ice and snow tourism in China has grown significantly since the country successfully hosted the Beijing Winter Olympics.Climatic conditions profoundly impact the development of ice and snow tourism;however,most studie... Ice and snow tourism in China has grown significantly since the country successfully hosted the Beijing Winter Olympics.Climatic conditions profoundly impact the development of ice and snow tourism;however,most studies have focused on constructing different climate suitability indicators for ice and snow tourism to evaluate individual regions,lacking horizontal comparative studies across multiple regions.This study aims to enrich the connotation of climate suitability for ice and snow sports,establish an evaluation model based on snowfall amount,temperature,and wind speed,and use daily meteorological data from 1991 to 2021 to horizontally compare the climate suitability for ice and snow sports in major ski tourism destinations in China.This study boasts four major findings:1)the average ice and snow sports climate index of each region decreases over time,and the overall suitability of the climate for ice and snow sports is reducing;2)northern Xinjiang exhibits the most evident regional differentiation from‘very suitable’to‘generally suitable’;3)the spatial zoning of climate suitability for ice and snow sports exhibits heterogeneity,as northern Xinjiang is divided into two‘suitable and above’zones with rotating empirical orthogonal function(REOF).Correspondingly,the four provinces of Hebei,Heilongjiang,Jilin,and Liaoning are divided into three‘generally suitable and above’zones;4)snowfall amount is the main factor affecting the climate suitability of ice and snow sports in the major ski tourist destinations in China. 展开更多
关键词 ice and snow tourism climate suitability rotating empirical orthogonal function(REof) spatial division China
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Level density of odd-A nuclei at saddle point 被引量:2
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作者 Wei Zhang Wei Gao +1 位作者 Gui-Tao Zhang Zhi-Yuan Li 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第8期164-173,共10页
Based on the covariant density functional theory,by employing the core–quasiparticle coupling(CQC)model,the nuclear level density of odd-A nuclei at the saddle point is achieved.The total level density is calculated ... Based on the covariant density functional theory,by employing the core–quasiparticle coupling(CQC)model,the nuclear level density of odd-A nuclei at the saddle point is achieved.The total level density is calculated via the convolution of the intrinsic level density and the collective level density.The intrinsic level densities are obtained in the finite-temperature covariant density functional theory,which takes into account the nuclear deformation and pairing self-consistently.For saddle points on the free energy surface in the(β_(2),γ)plane,the entropy and the associated intrinsic level density are compared with those of the global minima.By introducing a quasiparticle to the two neighboring even–even core nuclei,whose properties are determined by the five-dimensional collective Hamiltonian model,the collective levels of the odd-A nuclei are obtained via the CQC model.The total level densities of the^(234-240)U agree well with the available experimental data and Hilaire’s result.Furthermore,the ratio of the total level densities at the saddle points to those at the global minima and the ratio of the total level densities to the intrinsic level densities are discussed separately. 展开更多
关键词 level density Covariant density functional theory Core–quasiparticle coupling model Saddle point
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Revision of Water Function Division and Countermeasures for Water Resources Protection in Jiangjin District of Chongqing City in China
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作者 侯新 《Journal of Landscape Research》 2011年第12期54-57,70,共5页
According to the current situation and development planning of water resources in Jiangjin District of Three Gorge Reservoir Area at the upper reaches of Yangtze River,by combining with social needs,through the survey... According to the current situation and development planning of water resources in Jiangjin District of Three Gorge Reservoir Area at the upper reaches of Yangtze River,by combining with social needs,through the survey on pollution source and analysis of water quality,based on the Report of Water Function Division of Jiangjin District(2005) ,the adjustment and revision have been conducted on water function divisions,and corresponding protection targets and countermeasures for water resources have been proposed,so that the water function division can comply with the development situation of Jiangjin District,providing a reliable reference for the protection and reasonable utilization of water resources,enhancing the unified and effective supervision of water resources,promoting the sustainable use of water resources in Jiangjin District,and ensuring the sustainable development of regional society and environment. 展开更多
关键词 Three Gorges Reservoir Area Jiangjin DISTRICT WATER function division WATER resources protection COUNTERMEASURES
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Improved Calculation of Vibrational Energy Levels in F2 Molecule using the RKR Method
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作者 王建坤 吴振森 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第2期155-159,I0001,共6页
The potential energy curves of the ground state X2∑+g of the fluorine molecule have been accurately reconstructed employing the Ryderg-Klein-Rees (RKR) method extrapolated by a Hulburt and Hirschfeler potential fu... The potential energy curves of the ground state X2∑+g of the fluorine molecule have been accurately reconstructed employing the Ryderg-Klein-Rees (RKR) method extrapolated by a Hulburt and Hirschfeler potential function for longer internuclear distances. Solving the corresponding radial one-dimensional Schr?dinger equation of nuclear motion yields 22 bound vibrational levels above v=0. The comparison of these theoretical levels with the experimental data yields a mean absolute deviation of about 7.6 cm^-1 over the 23 levels. The highest vibrational level energy obtained using this method is 13308.16 cm?1 and the relative deviation compared with the experimental datum of 13408.49 cm^-1 is only 0.74%. The value from our method is much closer and more accurate than the value obtained by the quantum mechanical ab initio method by Bytautas. The reported agreement of the vibrational levels and dissociation energy with experiment is contingent upon the potential energy curve of the F2 ground state. 展开更多
关键词 Potential energy function Fluorine Vibrational levels distribution RKR method
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