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关于众包物流与配送的探讨 认领
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作者 李叶 《物流工程与管理》 2020年第3期17-19,共3页
随着电商的发展壮大,物流需求也越来越高,物流需求的增加带来了一系列问题,尤其体现在物流配送方面。而不断发展的物流业,也在不断进行着创新,众包物流方式应运而生。文中第一部分介绍了配送的现状及目前存在的问题,分析目前物流配送所... 随着电商的发展壮大,物流需求也越来越高,物流需求的增加带来了一系列问题,尤其体现在物流配送方面。而不断发展的物流业,也在不断进行着创新,众包物流方式应运而生。文中第一部分介绍了配送的现状及目前存在的问题,分析目前物流配送所面临的困局;第二部分介绍了众包物流及其优势和存在问题;第三部分探讨了能否利用众包物流来解决目前存在的配送问题。通过分析探讨,得出结论:众包物流要在政策约束及奖惩措施的激励下合法开展,在此基础上可以部分解决农村配送的问题并可以成为城市配送旺季的补充力量。众包物流的作用不止于此,未来,或许可以在生鲜配送等方面发挥更大的作用、解决更多的问题。 展开更多
关键词 配送 众包物流 农村配送
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Frequency–magnitude of landslides affected by the 27–29 November 2017 Tropical Cyclone Cempaka in Pacitan, East Java 认领
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作者 SAMODRA Guruh NGADISIH Ngadisih +3 位作者 MALAWANI Mukhamad Ngainul MARDIATNO Djati CAHYADI Ahmad NUGROHO Ferman Setia 《山地科学学报:英文版》 SCIE CSCD 2020年第4期773-786,共14页
Tropical cyclone(TC) Cempaka which occurred on 27–29 November 2017 has caused floods, landslides, and strong winds in certain areas of Java Island. Pacitan Regency was the most severely affected by TC Cempaka. The la... Tropical cyclone(TC) Cempaka which occurred on 27–29 November 2017 has caused floods, landslides, and strong winds in certain areas of Java Island. Pacitan Regency was the most severely affected by TC Cempaka. The landslide frequency–area distribution curve of event inventory i.e. TC Cempaka can help to understand landslide susceptibility, hazard, vulnerability, and risk. Landslides were identified by using a local government database and by comparing pre-and post-event high-resolution satellite imageries. Field investigation was carried out in March 2018 to November 2018 to verify the landslide location and update the information. Power law, inverse gamma, and double Pareto model were employed to describe the frequency–magnitude of landslide(mLS) triggered by TC Cempaka. The exponent β values of power law, inverse gamma, and double Pareto were 2.6±0.28(fitted for 8.5% of dataset), 2.2±0.08(fitted for 83% of dataset), and 2.3±0.09(best fitted for dataset), respectively. The P-values were 0.51, 0.67, and 0.91 for power law, inverse gamma, and double Pareto, respectively. This study revealed that rollover occurred at 200 and 300 m2 for double Pareto and inverse gamma, respectively. The cutoff points totaled 1096.49 ± 236.44 and 7235.4 ± 1896.7 m2 for double Pareto and power law, respectively. Rollover phenomenon was real and existed in the dataset because it was far from the minimum resolvable size of the landslide that the authors can delineate from the satellite images. mLS for Pacitan was distributed at around 2 to 4. The magnitude of large landslides was 3.2, that of medium landslides was less than 3, and that of small landslides was almost 4. Numerical estimation calculated a fixed mLS=3.01. Comparison analysis of β values obtained from several landslide inventories triggered by heavy rainfall suggests that the variability of β is related to the intensity and duration of rainfall. Triggering events, such as intensity and duration of rainfall, affect the proportion of large landslides that occur i 展开更多
关键词 LANDSLIDE Tropical cyclone Landslide magnitude Frequency distribution Area distribution Pacitan Regency
Marginal Bottleneck Identification in Power System Considering Correlated Wind Power Prediction Errors 认领
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作者 Bin Liu Ke Meng +1 位作者 Zhao Yang Dong Wang Zhang 《现代电力系统与清洁能源学报(英文)》 SCIE EI CSCD 2020年第1期187-192,共6页
This letter investigates how to identify the marginal bottleneck,which is defined as the constraint most likely to be violated with the increasing wind generation uncertainty of power system in real-time dispatch.The ... This letter investigates how to identify the marginal bottleneck,which is defined as the constraint most likely to be violated with the increasing wind generation uncertainty of power system in real-time dispatch.The presented method takes the correlation of wind power prediction error(WPPE)into account,leading to an ellipsoidal formulation of wind power generation region(WGR).Based on constructed WGR,the identification procedure is formulated as a max-max-min problem,which is solved by the algorithm based on iteration linear program with the proposed method to select appropriate initial points of WPPE.Finally,two cases are tested,demonstrating the efficacy and efficiency of the procedure to identify marginal bottleneck. 展开更多
关键词 BOTTLENECK ELLIPTICAL DISTRIBUTION HYPERBOLIC DISTRIBUTION wind power ACCOMMODATION
Law of Distribution of Quantities of Shells on Togolese Littoral 认领
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作者 Kossi Bollanigni Amey 《土木工程期刊(英文)》 2020年第1期69-82,共14页
This study aims at analyzing the repartition of the quantities of shells of sand sediments of Togolese littoral, and at determining the law underlying their longitudinal and transversal distributions. Samples (210), c... This study aims at analyzing the repartition of the quantities of shells of sand sediments of Togolese littoral, and at determining the law underlying their longitudinal and transversal distributions. Samples (210), collected all along Togolese littoral starting from Togo-Ghana border up to Togo-Benin border, are subject to the test of sieving. Each refusal on sieve is tested against construction of shells by hydrochloric acid. The determination of the quantity of shells according to their size and to longitudinal and transversal distributions on the littoral is completed. As a conclusion, the quantity of shells in the sediments is getting lower and lower starting from the aerial mid-beach (14.2%) to the mid-foreshore (11.80%), and getting higher and higher from the mid-foreshore (11.80%) to the low-foreshore (13.32%). It is getting lower and lower according to the direction of sediments’ transportations. This quantity of shells is high (40.87%) in the fine-grained sands (&#216 &#216 > 2 mm) and low (>24.26%) in the average-grained sands (0.125 mm ≤ &#216 ≤ 2 mm). The average quantity of shells of 12.67% is lower than the recommended maximum quantity (30%) for the sands used for concrete. Thus, for the concrete works, the littoral sands might be seen as useful since they are granulating for concrete. 展开更多
关键词 SEDIMENT Togolese LITTORAL Quantity of SHELLS DISTRIBUTION
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Experimental study of the elastic scattering of 10Be on 208Pb at the energy of around three times the Coulomb barrier 认领
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作者 段芳芳 杨彦云 +16 位作者 庞丹阳 胡碧涛 王建松 王康 杨过 Valdir Guimar?es 马朋 许世伟 刘星泉 马军兵 白真 胡强 金树亚 孙欣欣 姚佳盛 齐航凯 孙志宇 《中国物理C:英文版》 SCIE CAS CSCD 2020年第2期72-79,共8页
Elastic scattering of 10Be on a 208Pb target was measured at ELab=127 MeV,which corresponds to three times the Coulomb barrier.The secondary 10Be beam was produced at the Radioactive Ion Beam Line in Lanzhou of the He... Elastic scattering of 10Be on a 208Pb target was measured at ELab=127 MeV,which corresponds to three times the Coulomb barrier.The secondary 10Be beam was produced at the Radioactive Ion Beam Line in Lanzhou of the Heavy-Ion Research Facility in Lanzhou.The angular distribution of elastic scattering in the 10 Be+208Pb system shows a typical Fresnel diffraction peak.Optical model analysis of the angular distribution was performed using the Woods-Saxon,double-folding and global potentials.With the global potential,different density distributions were used.The results indicate that different density distributions for the projectile induce distinct effects in the angular distribution. 展开更多
关键词 ELASTIC SCATTERING RADIOACTIVE ion beam ANGULAR DISTRIBUTION optical model density DISTRIBUTION
Study of the Urban Coordinated Development Capability Index in the Yangtze River Economic Belt 认领
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作者 ZENG Gang YANG Shuting WANG Fenglong 《景观研究:英文版》 2020年第2期41-48,共8页
Coordinated development is a major concern in the construction strategy of the Yangtze River Economic Belt (YREB).However,there were few studies which have quantitatively measured the level of coordinated development ... Coordinated development is a major concern in the construction strategy of the Yangtze River Economic Belt (YREB).However,there were few studies which have quantitatively measured the level of coordinated development in the YREB.This paper aimed to propose an comprehensive index system of coordinated development based on the theories of growth pole and complex ecosystem and new guidelines of development from the central government.The index system was composed by 18 indicators within 4 domains including economic development,technology & innovation,communication & transportation,and ecological protection.The scores of coordinated development capability of the 110 prefecture-level cities in the YREB were calculated and examined using natural break point analysis,spatial autocorrelation analysis and rank-size analysis.It was shown that Shanghai,Nanjing and Wuhan were leading the coordinated development in the YREB.Generally,the scores of coordinated development capability were higher in the eastern region of the YREB,in which the cities performed well in the domains of economic development,technology & innovation and communication & transportation yet showed poor performance in ecological protection.Most cities in the middle reaches of Yangtze river ranked in the middle in the YREB in all the domains,except the provincial capitals.The western region of the YREB got the lowest score in the coordinated development capability besides the largest cities such as Chongqing,Chengdu,Kunming and Guiyang.The correlation coefficients between ecological protection and other domains were very low,suggesting that few cities have achieved a win-win situation between environment protection and socio-economic development.We suggested 3 ways to promote coordinated development in the YREB:establish multi-level institutional designs;enhance the innovation in green industries;and strengthen the joint prevention and control of ecological risks. 展开更多
关键词 The YANGTZE River Economic Belt(YREB) COORDINATED Development CAPABILITY Spatial DISTRIBUTION RANK-SIZE DISTRIBUTION Correlation Coeffi cient
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Assessing the collapse risk of Stipa bungeana grassland in China based on its distribution changes 认领
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作者 QIAO Xianguo GUO Ke +3 位作者 LI Guoqing ZHAO Liqing LI Frank Yonghong GAO Chenguang 《干旱区科学:英文版》 SCIE CSCD 2020年第2期303-317,共15页
The criteria used by International Union for Conservation of Nature(IUCN) for its Red List of Ecosystems(RLE) are the global standards for ecosystem-level risk assessment, and they have been increasingly used for biod... The criteria used by International Union for Conservation of Nature(IUCN) for its Red List of Ecosystems(RLE) are the global standards for ecosystem-level risk assessment, and they have been increasingly used for biodiversity conservation. The changed distribution area of an ecosystem is one of the key criteria in such assessments. The Stipa bungeana grassland is one of the most widely distributed grasslands in the warm-temperate semi-arid regions of China. However, the total distribution area of this grassland was noted to have shrunk and become fragmented because of its conversion to cropland and grazing-induced degradation. Following the IUCN-RLE standards, here we analyzed changes in the geographical distribution of this degraded grassland, to evaluate its degradation and risk of collapse. Past(1950-1980) distribution areas were extracted from the Vegetation Map of China(1:1,000,000). Present realizable distribution areas were equated to these past areas minus any habitat area losses. We then predicted the grassland’s present and future(under the Representative Concentration Pathway 8.5 scenario) potential distribution areas using maximum entropy algorithm(MaxEnt), based on field survey data and nine environmental layers. Our results showed that the S. bungeana grassland was mainly distributed in the Loess Plateau, Hexi Corridor, and low altitudes of the Qilian Mountains and Longshou Mountain. This ecosystem occurred mainly on loess soils, kastanozems, steppe aeolian soils and sierozems. Thermal and edaphic factors were the most important factors limiting the distribution of S. bungeana grassland across China. Since 56.1% of its past distribution area(4.9×10~4 km~2) disappeared in the last 50 a, the present realizable distribution area only amounts to 2.2×10~4 km~2. But only 15.7% of its present potential distribution area(14.0×10~4 km~2) is actually occupied by the S. bungeana grassland. The future potential distribution of S. bungeana grassland was predicted to shift towards northwest, and the total ar 展开更多
关键词 climate change LIMITING factors maximum entropy algorithm potential DISTRIBUTION realizable DISTRIBUTION Red List of ECOSYSTEMS LOESS PLATEAU
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Prevalence and Distribution of Cracked Posterior Teeth among Adult Patients 认领
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作者 Temiloluwa Olawale Ogundare Deborah Mojirade Ajayi +3 位作者 Paul Ikhodaro Idon Cornelius Tokunbo Bamise Adeleke Oke Oginni Temitope Ayodeji Esan 《口腔学期刊(英文)》 2020年第5期74-86,共13页
Background: There are challenges in detection and prevalence of cracked teeth, especially in asymptomatic cases. This underestimates the actual prevalence and possibility of preventive restorative treatment. Objective... Background: There are challenges in detection and prevalence of cracked teeth, especially in asymptomatic cases. This underestimates the actual prevalence and possibility of preventive restorative treatment. Objectives: To determine the prevalence and distribution of cracked posterior teeth among adult patients attending the dental clinic of OAUTHC, Ile-Ife, Osun State, Nigeria. Materials and Methods: A cross sectional study where consecutive patients aged 18 years and above were examined for the presence of cracked posterior teeth over a period of one year (May 2016-April 2017). The teeth were initially examined with the naked eye. Thereafter, transillumination, methylene blue dye and magnifying lens were used to aid detection of more cracks. Data was analyzed with the IBM Statistical Package for Social Sciences (SPSS) for Windows (version 21.0). Level of significance was set at p ≤ 0.05. Results: Out of the 64,370 posterior teeth examined for cracks in 3345 patients, 264 were diagnosed as cracked in 152 patients, giving a patient prevalence of 4.5% and tooth prevalence of 0.4%. Amongst the 152 patients, the prevalence was 9.1%. There was a slightly higher male preponderance while cracked tooth was observed to increase with age (p = 0.007). The skilled (56.6%) and those that attained tertiary education (77.6%, p = 0.023) had more cracked teeth. Mandibular first molar (19.7%) was the most frequently cracked tooth type. The cracks were usually centrally placed (91.7%) and run in a mesiodistal direction (61%). Transillumination (44.7%) detected more cracked teeth. Conclusion: Prevalence of cracked tooth was observed to be low with a slightly higher proportion in male and the figure increases with age. Mandibular first molar was the most frequently cracked tooth while transillumination was the most useful diagnostic tool. Most cracks ran in the mesiodistal direction and fracture lines were usually centrally placed. 展开更多
关键词 Cracked TOOTH PREVALENCE DISTRIBUTION ADULT POSTERIOR TOOTH
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武陵山片区传统村落空间分布及影响因素研究 认领
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作者 何银春 谢静 梁越 《中南林业科技大学学报:社会科学版》 2020年第1期84-92,共9页
研究特定区域传统村落的空间分布及影响因素,可为传统村落的政策制定和合理开发提供科学依据。武陵山片区是中国区域发展和扶贫攻坚规划里的新概念,片区作为跨省交界面大、少数民族聚居多、贫困人口分布广的集中连片特困地区,其传统村... 研究特定区域传统村落的空间分布及影响因素,可为传统村落的政策制定和合理开发提供科学依据。武陵山片区是中国区域发展和扶贫攻坚规划里的新概念,片区作为跨省交界面大、少数民族聚居多、贫困人口分布广的集中连片特困地区,其传统村落保存面积较大、保护完整,社会、历史、文化内涵深厚,具有重要的利用价值和学术研究价值。以武陵山片区的735个中国传统村落为研究对象,运用ArcGIS空间分析软件和空间结构研究方法,对武陵山片区传统村落的空间分布特征以及影响因素进行研究。结果表明:1)武陵山片区传统村落的分布为凝聚型;空间分布呈"核心多、边缘少"的格局。2)传统村落空间分布集中,极具不均衡性。3)传统村落主要分布在雨热同期的山地、近河流地区,受地形、河流等自然因素影响显著,受经济、交通与民族文化影响较小。根据研究结果,进一步提出了武陵山片区及同类型区域传统村落合理开发的建议,以期为特定区域传统村落的保护和可持续发展提供借鉴。 展开更多
关键词 传统村落 武陵山片区 分布 影响因素
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新发展理念下习近平关于分配的重要论述探析 认领
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作者 吴松 《理论建设》 2020年第2期41-48,共8页
习近平关于分配的重要论述是对马克思主义分配理论的坚持发展,是中国特色社会主义进入新时代的理论创新。习近平关于分配的重要论述将生产与分配、国内与国际、公平与效率、目标与价值有机结合起来,是一个完整的理论体系。站在新发展理... 习近平关于分配的重要论述是对马克思主义分配理论的坚持发展,是中国特色社会主义进入新时代的理论创新。习近平关于分配的重要论述将生产与分配、国内与国际、公平与效率、目标与价值有机结合起来,是一个完整的理论体系。站在新发展理念的立场上对其进行阐释,主要包含坚持与时俱进,推动分配理论制度创新;不断协调分配失衡,实现共同富裕的理想目标;坚持绿色生产,向"绿水青山"要"金山银山";坚持分配的国际视野,回应国际不合理分配秩序;坚持共享发展理念,遵循以人民为中心的价值取向等五个方面。 展开更多
关键词 新发展理念 中国特色社会主义 分配
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Pair distribution function analysis: Fundamentals and application to battery materials 认领
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作者 王雪龙 谭莎 +1 位作者 杨晓青 胡恩源 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第2期71-80,共10页
Battery materials are of vital importance in powering a clean and sustainable society.Improving their performance relies on a clear and fundamental understanding of their properties,in particular,structural properties... Battery materials are of vital importance in powering a clean and sustainable society.Improving their performance relies on a clear and fundamental understanding of their properties,in particular,structural properties.Pair distribution function(PDF)analysis,which takes into account both Bragg scattering and diffuse scattering,can probe structures of both crystalline and amorphous phases in battery materials.This review first introduces the principle of PDF,followed by its application in battery materials.It shows that PDF is an effective tool in studying a series of key scientific topics in battery materials.They range from local ordering,nano-phase quantification,anion redox reaction,to lithium storage mechanism,and so on. 展开更多
关键词 BATTERY materials PAIR DISTRIBUTION function(PDF)
Small x phenomenology on gluon evolution through the BFKL equation in light of a constraint in multi-Regge kinematics 认领
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作者 Pragyan Phukan Madhurjya Lalung Jayanta Kumar Sarma 《理论物理通讯:英文版》 SCIE CAS CSCD 2020年第2期50-59,共10页
We investigate the impact of so-called kinematic constraint on gluon evolution at small x.Implanting the constraint on the real emission term of the gluon ladder diagram,we obtain an integro-differential form of the B... We investigate the impact of so-called kinematic constraint on gluon evolution at small x.Implanting the constraint on the real emission term of the gluon ladder diagram,we obtain an integro-differential form of the Balitsky-Fadin-Kuraev-Lipatov(BFKL)equation.Later we solve the equation analytically using the method of characteristics.We sketch the Bjorken x and transverse momentum kt2 dependence of our solution of unintegrated gluon distributions f(x,kt2)in the kinematic constraint supplemented BFKL equation and contrasted the same with the original BFKL equation.Then we extract the integrated gluon density xg(x,Q2)from unintegrated gluon distributions f(x,kt2)and compared our theoretical prediction with that of global data fits,namely NNPDF3.1 sx and CT14.Finally we illustrate the phenomenological implication of our solution for unintegrated gluon distribution f(x,kT2)towards exploring high precision HERA DIS data by the theoretical prediction of proton structure functions(F2 and FL). 展开更多
关键词 PARTON EVOLUTION equation GLUON distribution function perturbative QCD
低钾胁迫对苹果砧木M9T337幼苗光合荧光特性及13C吸收分配的影响 认领
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作者 徐新翔 侯昕 +3 位作者 王芬 贾志航 葛顺峰 姜远茂 《园艺学报》 CAS CSCD 北大核心 2020年第3期529-540,共12页
以1年生苹果砧木M9T337幼苗为试材,采用叶绿素荧光分析和13C同位素示踪技术,水培条件下研究了不同供钾水平(0.02、0.5、2和6 mmol·L^-1)对幼苗光合生理特性、叶绿素荧光特性以及13C光合产物积累和分配的影响。结果表明:与正常供钾(... 以1年生苹果砧木M9T337幼苗为试材,采用叶绿素荧光分析和13C同位素示踪技术,水培条件下研究了不同供钾水平(0.02、0.5、2和6 mmol·L^-1)对幼苗光合生理特性、叶绿素荧光特性以及13C光合产物积累和分配的影响。结果表明:与正常供钾(6mmol·L^-1K^+)对照处理相比,低钾胁迫下苹果砧木M9T337幼苗各器官生物量、净光合速率(Pn)和气孔导度(Gs)均显著下降,胞间CO2浓度(Ci)先下降后上升。低钾胁迫下幼苗叶片的光化学猝灭系数(qP)、PSⅡ实际光化学效率(ΦPSⅡ)、PSⅡ电子传递速率(ETR)和PSⅡ最大光化学效率(Fv/Fm)均显著下降,基础荧光(F0)和非光化学猝灭系数(NPQ)显著升高,且低钾胁迫程度越大,叶绿素荧光参数变化幅度越大。随着处理时间的延长,低钾胁迫处理下的RuBP羧化酶(Rubisco)和碳代谢酶活性逐渐降低,35 d后酶活降至最低水平。13C示踪试验结果表明,低钾胁迫显著影响了碳素同化物的积累和分配。两年平均,13C标记结束6 h后0.02、0.5、2 mmol·L^-1 K^+处理的幼苗根系13C积累量分别为对照的15.59%、26.62%和59.72%;标记结束72 h后,0.02、0.5、2 mmol·L^-1 K^+处理下的幼苗叶片13C分配率高达70.44%、67.61%、66.02%,分别较对照提高14.00%、9.44%、6.87%,而根系的13C分配率为10.54%、11.84%、13.34%,分别为对照的61.87%、69.50%、78.31%。结果显示,低钾胁迫降低叶片气孔导度,破坏PSⅡ反应中心,降低光反应阶段还原力的供应以及碳同化能力,从而抑制光合作用及碳素向根系的运输,并且抑制程度与低钾胁迫时间和程度显著相关。 展开更多
关键词 苹果 砧木 低钾胁迫 光合 荧光 13C吸收 分配
石榴在陕西的引种与推广 认领
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作者 田益凡 《农业考古》 2020年第1期132-137,共6页
陕西作为我国石榴主产地之一,早在汉代就有关于石榴种植的记载,但对石榴在陕西的引种、推广的研究尚处于空白,目前普遍认为石榴最早由张骞自西域带回。从皇家园林的观赏植物到寻常人家喜爱的果树,各朝文学作品与典籍中可见石榴的种植范... 陕西作为我国石榴主产地之一,早在汉代就有关于石榴种植的记载,但对石榴在陕西的引种、推广的研究尚处于空白,目前普遍认为石榴最早由张骞自西域带回。从皇家园林的观赏植物到寻常人家喜爱的果树,各朝文学作品与典籍中可见石榴的种植范围不断扩大,用途也由最初的园林景观扩展为食用、药用、装饰等多个方面。从清代各州县地方志记载中可以还原出清末石榴在陕西的大致分布,其范围已经遍及陕西省大部分地区,成为陕西最为普遍的果树之一。陕西石榴品种繁多,如今有的品种已所剩无几,保护品种多样性是生态平衡的必要前提。 展开更多
关键词 石榴 陕西 引种 推广 分布
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Field and CFD Study of Fuel Distribution in Pulverized Fuel(PF)Boilers 认领
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作者 CIUKAJ Szymon HERNIK Bartlomiej 《热科学学报:英文版》 SCIE EI CAS CSCD 2020年第3期535-545,共11页
The article presents both field and CFD results of a new concept of a mechanical pulverized fuel(PF)distributor.The goal of the study was to improve the pulverized coal-air mixture separation in PF boilers where the f... The article presents both field and CFD results of a new concept of a mechanical pulverized fuel(PF)distributor.The goal of the study was to improve the pulverized coal-air mixture separation in PF boilers where the fuel preparation and feeding system was operated in a combined coal and biomass grinding conditions.The numerical analysis was preceded after a field study,where measurements were carried out in a pulverized coal-fired(PC)boiler equipped with a technology of NOx reduction by means of primary methods.Proper distribution of a pulverized coal-air mixture to the individual burners is one of the fundamental tasks of the combustion systems where the primary methods are implemented to control the NOx emission.Problems maintaining the proper distribution of fuel to the burners related primarily to the boilers where the coal and biomass co-grinding is used.Changing the load of coal-mills and fuel type at the same time(i.e.,different types of biomass)could result in less effective separation of pulverized fuel particles in PF distributors.Selection of an appropriate construction of a distributor will allow the better control of the combustion process which results in decreased NOx emission while keeping the proper combustion efficiency,i.e.,less unburned carbon(UBC)in the fly ash.The results of the field measurements made it possible to create a CFD distribution base model,which was used for the analysis of a new splitter construction to be used in a PF distributor.Subsequent analysis of the numerical splitter enables precise analysis of its construction,including the efficiency of separation and the prediction of conveying of the coal and biomass particles. 展开更多
关键词 pulverized fuel(PF)boiler NOx reduction biomass co-firing fuel distribution
滇池捞鱼河河口沉积物中正构烷烃的分布特征及来源解析 认领
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作者 罗玉 黄立成 +1 位作者 秦江 段典榕 《环境科学导刊》 2020年第1期5-9,共5页
通过对捞鱼河河口附近的柱状沉积物分层样品中的正构烷烃和TOC进行研究,分析其含量变化趋势和分布特征以及各项生物示踪指标,来研究沉积物中有机质的贡献源。研究结果表明,捞鱼河河口沉积物中有机质来源由草本植物逐步变为木本植物,从3... 通过对捞鱼河河口附近的柱状沉积物分层样品中的正构烷烃和TOC进行研究,分析其含量变化趋势和分布特征以及各项生物示踪指标,来研究沉积物中有机质的贡献源。研究结果表明,捞鱼河河口沉积物中有机质来源由草本植物逐步变为木本植物,从30cm深度至表层的沉积物中有机质贡献源中增加了藻类和化石燃料。 展开更多
关键词 沉积物 正构烷烃 分布特征 来源解析 滇池
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Microscopic and macroscopic atomization characteristics of a pressure-swirl atomizer, injecting a viscous fuel oil 认领
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作者 Seyed Mohammad Ali Najafi Pouria Mikaniki Hojat Ghassemi 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2020年第1期9-22,共14页
Combustion of heavy fuels is one of the main sources of greenhouse gases, particulate emissions, ashes, NOxand SOx. Gasification is an advanced and environmentally friendly process that generates combustible and clean... Combustion of heavy fuels is one of the main sources of greenhouse gases, particulate emissions, ashes, NOxand SOx. Gasification is an advanced and environmentally friendly process that generates combustible and clean gas products such as hydrogen. Some entrained flow gasifiers operate with Heavy Fuel Oil(HFO) feedstock. In this application, HFO atomization is very important in determining the performance and efficiency of the gasifiers.The atomization characteristics of HFO(Mazut) discharging from a pressure-swirl atomizer(PSA) are studied for different pressures difference(Δp) and temperatures in the atmospheric ambient. The investigated parameters include atomizer mass flow rate( _m), discharge coefficient(CD), spray cone angle(θ), breakup length(Lb), the unstable wavelength of undulations on the liquid sheet(λs), global and local SMD(sauter mean diameter) and size distribution of droplets. The characteristics of Mazut sheet breakup are deduced from the shadowgraph technique. The experiments on Mazut film breakup were compared with the predictions obtained from the liquid film breakup model. Validity of the theory for predicting maximum unstable wavelength was investigated for HFO(as a highly viscous liquid). A modification on the formulation of maximum unstable wavelength was presented for HFO. SMD decreases by getting far from the atomizer. The measurement for SMD and θ were compared with the available correlations. The comparisons of the available correlations with the measurements of SMD andθ show a good agreement for Ballester and Varde correlations, respectively. The results show that the experimental sizing data could be presented by Rosin-Rammler distributions very well at different pressure difference and temperatures. 展开更多
关键词 GASIFIER Heavy fuel oil ATOMIZATION Pressure-swirl ATOMIZER Mazut Size distribution Wavelength Viscosity
高硼胁迫对纽荷尔脐橙幼苗微量元素吸收与分配的影响 认领
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作者 胡萍 陈玉花 +4 位作者 周高峰 姚锋先 管冠 钟八莲 刘桂东 《中国土壤与肥料》 CAS CSCD 北大核心 2020年第2期179-183,共5页
研究高硼胁迫对纽荷尔脐橙幼苗微量元素(B、Mn、Fe、Cu、Zn、Mo)吸收与分配的影响,以期为脐橙的硼肥营养生理和生产中科学施用微量元素提供理论依据。以纽荷尔脐橙幼苗为试材,利用营养液培养方法进行高硼处理(B:200μmol/L)和适硼处理(B... 研究高硼胁迫对纽荷尔脐橙幼苗微量元素(B、Mn、Fe、Cu、Zn、Mo)吸收与分配的影响,以期为脐橙的硼肥营养生理和生产中科学施用微量元素提供理论依据。以纽荷尔脐橙幼苗为试材,利用营养液培养方法进行高硼处理(B:200μmol/L)和适硼处理(B:20μmol/L,对照),测定根、砧木茎、上部接穗茎、下部接穗茎、上部叶、下部叶6个部位微量元素的含量,并计算各部位微量元素积累量和分配率。高硼胁迫下纽荷尔脐橙幼苗根干物重显著下降,其他部位干物重没有明显变化,且各部位B含量和积累量均显著增加,B在叶片中的分配率也明显提高。Mn、Fe、Zn、Mo主要在根部富集,高硼胁迫使各部位中的Mn含量显著下降,根部Fe含量和积累量也显著降低,但各部位中Mn、Cu、Mo的分配率无明显变化;高硼胁迫显著降低了下部叶Cu含量,也使上部接穗茎Zn含量和积累量显著下降,并且根部和砧木茎Mo含量显著增加。 展开更多
关键词 高硼胁迫 纽荷尔脐橙 微量元素 吸收 分配
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Performance Analysis of Cushioned Sport Soles with Plantar Pressure Test 认领
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作者 李静 于海滨 +2 位作者 崔丽娜 张锐 邱夷平 《东华大学学报:英文版》 EI CAS 2020年第2期108-115,共8页
Plantar pressure distribution of the designed cushioned soles was studied and compared with that of the commercially available sport shoes.A three-dimensional motion measurement system was used to obtain the peak plan... Plantar pressure distribution of the designed cushioned soles was studied and compared with that of the commercially available sport shoes.A three-dimensional motion measurement system was used to obtain the peak plantar force,the peak plantar pressure,force-time integrals and pressure-time integrals,and one-way analysis of variance was used to analyze the performance of the designed cushioned shoes.The results revealed that in normal walking and jogging states,compared with the commercially available sport shoes,the peak plantar pressure in the heel region decreased by 13.65%and 6.05%,respectively.The peak plantar force decreased by 15.98%and 15.32%,respectively.The force-time integral decreased by 4.36%and 6.83%,respectively,and the pressure-time integral decreased by 10.58%and 11.00%,respectively.In conclusion,the cushioning performance of shoes is related to the exercise mode.For normal walking,the designed cushioned soles absorbed greater impact in the heel region,which was effectively cushioned,whereas in the jogging state,the designed cushioned soles exhibited a favorable cushioning effect in the forefoot region.The designed cushioned soles exhibited cushioning performance through the coupling design of material and structure,which effectively reduced impact force when landing and could optimize plantar pressure distribution. 展开更多
关键词 BIONIC structure midsole PLANTAR PRESSURE distribution PEAK PLANTAR
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Randomized statistical inference:A unified statistical inference frame of frequentist,fiducial,and Bayesian inference 认领
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作者 Zhongzhan Zhang Jiajia Dai Zhenhai Yang 《中国科学:数学英文版》 SCIE CSCD 2020年第5期1007-1028,共22页
We propose randomized inference(RI),a new statistical inference approach.RI may be realized through a randomized estimate(RE)of a parameter vector,which is a random vector that takes values in the parameter space with... We propose randomized inference(RI),a new statistical inference approach.RI may be realized through a randomized estimate(RE)of a parameter vector,which is a random vector that takes values in the parameter space with a probability density function(PDF)that depends on the sample or sufficient statistics,such as the posterior distributions in Bayesian inference.Based on the PDF of an RE of an unknown parameter,we propose a framework for both the vertical density representation(VDR)test and the construction of a confidence region.This approach is explained with the aid of examples.For the equality hypothesis of multiple normal means without the condition of variance homogeneity,we present an exact VDR test,which is shown as an extension of one-way analysis of variance(ANOVA).In the case of two populations,the PDF of the Welch statistics is given by using the RE.Furthermore,through simulations,we show that the empirical distribution function,the approximated t,and the RE distribution function of Welch statistics are almost equal.The VDR test of the homogeneity of variance is shown to be more efficient than both the Bartlett test and the revised Bartlett test.Finally,we discuss the prospects of RI. 展开更多
关键词 confidence distribution PIVOT randomized inference vertical density representation VDR test
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