期刊文献+
共找到3,487篇文章
< 1 2 175 >
每页显示 20 50 100
论中国西南地区早期佛像 被引量:22
1
作者 罗二虎 《考古》 CSSCI 北大核心 2005年第6期66-73,共8页
中国西南地区在东汉晚期至蜀汉前期至蜀汉前期已出现早期佛像,主要见到随葬钱树上的铜或陶质佛像,也有部分崖墓石刻画像中的石佛像,它们很可能代表了中国内地最早阶段的典型佛像。早期佛像在西南地区流行应与本土传统的升仙信仰有关,可... 中国西南地区在东汉晚期至蜀汉前期至蜀汉前期已出现早期佛像,主要见到随葬钱树上的铜或陶质佛像,也有部分崖墓石刻画像中的石佛像,它们很可能代表了中国内地最早阶段的典型佛像。早期佛像在西南地区流行应与本土传统的升仙信仰有关,可能是经由"丝绸之路"传入川西地区后在此区域内传播。 展开更多
关键词 中国西南地区 culture China 佛像 早期 the HAVE first and WORKS data that LATE from some form very MUST with to The are of via may on
原文传递
“可以适用习惯”的法教义学解释 被引量:19
2
作者 谢晖 《现代法学》 CSSCI 北大核心 2018年第2期3-24,共22页
如何理解"可以适用习惯"?这是个应当从法教义学视角论述的话题。法教义学追求法学解释的法律规范引导、裁判效果取向和法律体系化建构,它们分别是法教义学的前提、目的和方法。以此来衡量,则"可以适用习惯"这一法... 如何理解"可以适用习惯"?这是个应当从法教义学视角论述的话题。法教义学追求法学解释的法律规范引导、裁判效果取向和法律体系化建构,它们分别是法教义学的前提、目的和方法。以此来衡量,则"可以适用习惯"这一法律规定中的"可以"、"适用"和"习惯"等具体词汇,都应得到符合法律原则和精神宗旨的、用以维护法律和裁判严肃性的、补强法律体系及其效力的教义学解释。本着法教义学的这些宗旨,本文尝试对"可以适用习惯"这个法定内容中的具体词汇予以解释。 展开更多
关键词 法教义学 可以 适用 习惯 司法
下载PDF
法律语篇中shall和may的翻译对比研究 被引量:18
3
作者 王子颖 《上海翻译》 CSSCI 北大核心 2013年第4期52-57,共6页
法律英语中shall和may是最主要的情态动词。本研究利用中国大陆和香港法律法规汉英平行语料库,把shall和may分别放在肯定和否定两种形式下,对比两库中它们的使用频率,发现大陆语料库中shall和may not被过度使用,may和shall not却使用不... 法律英语中shall和may是最主要的情态动词。本研究利用中国大陆和香港法律法规汉英平行语料库,把shall和may分别放在肯定和否定两种形式下,对比两库中它们的使用频率,发现大陆语料库中shall和may not被过度使用,may和shall not却使用不足。由此提出译者必须谨慎对待情态动词,只有充分了解情态动词的深层语义内涵,才能在最大程度上实现法律翻译的准确性。 展开更多
关键词 SHALL may 情态动词 法律法规汉英平行语料库 翻译对比
下载PDF
A nontrivial product in the stable homotopy groups of spheres 被引量:17
4
作者 LIU XiuguiInstitute of Mathematics, Chinese Academy of Sciences, Beijing 100080, China 《Science China Mathematics》 SCIE 2004年第6期831-841,共11页
Let A be the mod p Steenrod algebra for p an arbitrary odd prime. In 1962, Liulevicius described h i and b k in Ext* A ’*(Zp,Zp) having bigrading (1, sui— 1) and (2, 2p k+1 x(p— 1)), respectively. In this paper we ... Let A be the mod p Steenrod algebra for p an arbitrary odd prime. In 1962, Liulevicius described h i and b k in Ext* A ’*(Zp,Zp) having bigrading (1, sui— 1) and (2, 2p k+1 x(p— 1)), respectively. In this paper we prove that for p ≥ 7, n ≥ 4 and $3 \leqslant s < p - 1, h_0 b_{n - 1} \tilde \gamma _s \in Ext_A^{s + 3,p^n q + sp^2 q + (s - 1)pq + (s - 1)q + s - 3} (Z_p ,Z_p )$ survives to E∞ in the Adams spectral sequence, where q = 2(p — 1). 展开更多
关键词 stable homotopy groups of spheres Adams spectral sequence Toda-Smith spectra may spectral sequence
原文传递
甜玉米胚乳突变基因的研究进展及其在育种中应用的策略 被引量:12
5
作者 杨泉女 王蕴波 《分子植物育种》 CAS CSCD 2005年第6期877-882,共6页
甜玉米受一个或多个隐性基因控制的胚乳突变体。到目前为止,已发现至少有14个甜玉米胚乳隐性突变基因,其中有8个胚乳突变基因(su1,sh2,bt1,bt2,ae1,du1,wx1,se1)已应用于商业化育种。目前,已定出了与甜玉米有关的主要胚乳突变基因在玉... 甜玉米受一个或多个隐性基因控制的胚乳突变体。到目前为止,已发现至少有14个甜玉米胚乳隐性突变基因,其中有8个胚乳突变基因(su1,sh2,bt1,bt2,ae1,du1,wx1,se1)已应用于商业化育种。目前,已定出了与甜玉米有关的主要胚乳突变基因在玉米染色体上的确切位置,这些胚乳突变基因大多数已经被克隆和测序,而且对这些基因在胚乳碳水化合物合成途径中的作用也有了较深入的了解。本文综述了8个已应用于商业化育种的甜玉米胚乳突变基因的染色体位点、编码的产物及其表现型,介绍这8个甜玉米胚乳突变基因的分类、遗传效应及其互作效应,并提出其在我国甜玉米育种中的应用策略,旨在为甜玉米的深入研究和开发利用提供参考。 展开更多
关键词 甜玉米(Zea may L.) 胚乳突变基因 研究进展 应用策略
下载PDF
盘龙城商代宫殿基址讨论 被引量:14
6
作者 杜金鹏 《考古学报》 CSSCI 北大核心 2005年第2期161-184,共24页
The large-sized rammed-earth building foundations on the Panlongcheng site at Huangpi are remains of early Shang period palace complex. The No. 1 Panlongcheng palace consists of four rooms with wooden-framed walls. Th... The large-sized rammed-earth building foundations on the Panlongcheng site at Huangpi are remains of early Shang period palace complex. The No. 1 Panlongcheng palace consists of four rooms with wooden-framed walls. The two rooms in the middle each have two doors on the northern and southern sides respectively;while the two end rooms have only southern doors. So the No. 1 palace must have been in the center of the whole building complex. The roof supported by peripheral columns and wooden-framed walls can be reconstructed to be hipped and single- or double- eaved. The hypothesis that the No. 1 palace may have had projecting-eaves columns has not been confirmed. The No. 2 palace is an open hall without peripheral walls and room division; its roof is supported by peripheral columns only. The idea of reconstructing it as a building with pilasters and multiple rooms seems to lack archaeological evidence. The remaining vestiges show that there were side corridors in the two flanks of the main hall of the No. 2 palace. Referring to the Shang period palace material unearthed from the Shang city-site at Yanshi and other localities, it can be inferred that either of the Nos. 1 and 2 palaces must have had an eastern corridor and a western one, and, in addition, the No. 2 palace must have had a southern corridor with a gate house. The Nos. 1--3 palaces of the Panlongcheng site formed three compounds located one behind another, and belonged to the type of court-and-living building complex. Among them the No. 2 palace was the outer court for holding great ceremonies, the No. 1 palace was the inner court for handling daily administrative affairs, and the No. 3 palace was the king and queen's living place. To the southeast of the No. 2 palace remains a group of rammed-earth house-foundations, which must have been left over from another type of palace building, possibly an ancestral temple. The remaining city-walls at Panlongcheng must have belonged to the peripheral city-walls. The palace area is in the northeast of the encl 展开更多
关键词 宫殿基址 ANOTHER 盘龙城 have MUST there 商代 with center that EITHER and The only from type while house Among great place group which two for EACH open idea show over can Nos one of to in are be may has
原文传递
Periodontitis may induce gut microbiota dysbiosis via salivary microbiota 被引量:13
7
作者 Jun Bao Lili Li +5 位作者 Yangheng Zhang Min Wang Faming Chen Shaohua Ge Bin Chen Fuhua Yan 《International Journal of Oral Science》 SCIE CAS CSCD 2022年第3期349-359,共11页
The aim of this study was to identify whether periodontitis induces gut microbiota dysbiosis via invasion by salivary microbes.First,faecal and salivary samples were collected from periodontally healthy participants(P... The aim of this study was to identify whether periodontitis induces gut microbiota dysbiosis via invasion by salivary microbes.First,faecal and salivary samples were collected from periodontally healthy participants(PH group,n=16)and patients with severe periodontitis(SP group,n=21)and analysed by 16S ribosomal RNA sequencing.Significant differences were observed in both the faecal and salivary microbiota between the PH and SP groups.Notably,more saliva-sourced microbes were observed in the faecal samples of the SP group.Then,the remaining salivary microbes were transplanted into C57BL6/J mice(the C-PH group and the C-SP group),and it was found that the composition of the gut microbiota of the C-SP group was significantly different from that of the C-PH group,with Porphyromonadaceae and Fusobacterium being significantly enriched in the C-SP group.In the colon,the C-SP group showed significantly reduced crypt depth and zonula occludens-1 expression.The m RNA expression levels of pro-inflammatory cytokines,chemokines and tight junction proteins were significantly higher in the C-SP group.To further investigate whether salivary bacteria could persist in the intestine,the salivary microbiota was stained with carboxyfluorescein diacetate succinimidyl ester and transplanted into mice.We found that salivary microbes from both the PH group and the SP group could persist in the gut for at least 24 h.Thus,our data demonstrate that periodontitis may induce gut microbiota dysbiosis through the influx of salivary microbes. 展开更多
关键词 Periodontitis may induce gut microbiota dysbiosis via salivary microbiota
下载PDF
5月华南降雨前期海温信号特征分析 被引量:12
8
作者 张成扬 蒋跃林 +3 位作者 杨崧 胡春迪 张团团 邓开强 《气象与环境科学》 2015年第2期29-35,共7页
利用国家气象信息中心提供的1983—2013年31 a月平均全国降雨数据、美国国家环境预报中心/国家大气研究中心(NCEP/NCAR)大气再分析资料及美国国家海洋大气管理局(NOAA)的海表面温度资料,分析了华南前汛期(5月)降雨的前期海温信号。结果... 利用国家气象信息中心提供的1983—2013年31 a月平均全国降雨数据、美国国家环境预报中心/国家大气研究中心(NCEP/NCAR)大气再分析资料及美国国家海洋大气管理局(NOAA)的海表面温度资料,分析了华南前汛期(5月)降雨的前期海温信号。结果表明,华南5月份降雨在印度洋和太平洋的早期海温信号于1998年前后有显著的年代际变化。1998年之前,前期海温信号主要是和处于发展位相的厄尔尼诺有关的热带东太平洋和北印度洋的海温异常,它主要通过大气桥作用激发的菲律宾反气旋影响华南5月降雨异常。1998年之后,前期海温信号主要是和中高纬北太平洋的马蹄形海温异常有关,它可以通过影响中纬度瞬变活动调制副热带急流的强度和位置,引起华南降水异常。利用2014年4月的海温信号对5月华南降水的预报结果及5月的大气环流,验证了这种海温信号的存在及其引起华南5月降雨异常的机理,并运用美国国家环境预报中心气候预报系统(CFSv2)的模式预报数据,证实了这两类前期海温信号的存在。本研究表明,这两类前期海温信号能为5月份华南降雨未来的业务预报提供一定参考。 展开更多
关键词 5月 华南前汛期降雨 前期信号 可预报性
下载PDF
Early Ordovician strongly peraluminous granite in the middle section of the Yarlung Zangbo junction zone and its geological significance 被引量:12
9
作者 ZHANG ShiZhen LI FenQi +2 位作者 LI Yong LIU Wei QIN YaDong 《Science China Earth Sciences》 SCIE EI CAS 2014年第4期630-643,共14页
LA-ICP-MS zircon U-Pb isotopic dating and rock geochemical analysis were done of the Xarru granite in the middle section of the Yarlung Zangbo junction zone. Zircon 2-6pb/Z38u weighted mean ages of 474.9±2.3 and ... LA-ICP-MS zircon U-Pb isotopic dating and rock geochemical analysis were done of the Xarru granite in the middle section of the Yarlung Zangbo junction zone. Zircon 2-6pb/Z38u weighted mean ages of 474.9±2.3 and 478.3±1.7 Ma have been obtained for two gneiss granite samples respectively, which represent the formation age of the granite. This is the first discovery of the Early Ordovician magmatism in the Yarlung Zangbo junction zone. The rocks are high-K calcic-alkalic granite, contain tour- maline but not hornblende, with aluminum saturation index (ASI) of A/CNK〉I.1 (1.10-1.20), and are enriched in Rb, Th and U and relatively depleted in Ba, Nb, Sr, Zr, Ti and Eu. They are strongly peraluminous S-type granite, resulting from partial melting of argillaceous components in the crust in a syn-collisional setting. According to previous studies as well as the analy- sis in this paper, the formation of the Xarru granite is probably related to the Andean-type orogeny in the process of subduction of the Proto-Tethys Ocean towards the Gondwanaland, and it is a product of partial melting of the thickened upper crust as a result of collision between blocks or micro-blocks in the northern margin of the Gondwana supercontinent in the process of oceanic subduction. The Xarru granite is identified as the Early Ordovician granite, indicating that the wall rocks had probably formed in the Cambrian or Precambrian. 展开更多
关键词 A crustal basement may exist in the Xarru region. Yarlung Zangbo Junction Zone Early Ordovician strongly peraluminous granite collisional setting crustal basement
原文传递
Growth characteristics and response to climate change of Larix Miller tree-ring in China 被引量:9
10
作者 SUN Yu1,4, WANG LiLi1,2,3, CHEN Jin5, DUAN JianPing1,4, SHAO XueMei1,2 & CHEN KeLong6 1 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China 2 Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, China +3 位作者 3 Institute of Desert and Meteorology, China Meteorological Administration, Urumqi 830002, China 4 Graduate University of Chinese Academy of Sciences, Beijing 100049, China 5 Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China 6 School of Life and Geography Sciences, Qinghai Normal University, Xining 810008, China 《Science China Earth Sciences》 SCIE EI CAS 2010年第6期871-879,共9页
As one of the earliest species used in dendrochronological studies, Larix responds sensitively to climate change. In this study, nine larch species and one variety from eleven sites were collected to study the growth ... As one of the earliest species used in dendrochronological studies, Larix responds sensitively to climate change. In this study, nine larch species and one variety from eleven sites were collected to study the growth characteristics of tree-ring width using dendrochronological methods. Ten residual tree-ring chronologies were developed to analyze their relationships with regional standardized anomaly series by Pearson’s correlation analysis. The results suggest that most of the chronologies had significantly positive correlations with the mean temperature and mean maximum temperature in May. The spring temperature evidently limited the radial growth of the larch species without precipitation control. The largest mean tree-ring width was found in Himalayan Larch in Jilong, whereas Master Larch in Si’er reflected the smallest mean value. Both species presented little climate information in this study. Chinese, Potanin, and Tibetan larches are significantly correlated with climate change, implying a huge potential for climate history reconstruction. The elevation of the sampling sites appears to be an important condition for tree-ring growth of larches responding to climate factors. 展开更多
关键词 LARIX MILLER TREE-RING CLIMATE CHANGE mean temperature in may
原文传递
Mitogen-activated protein kinase signal pathways play an important role in right ventricular hypertrophy of tetralogy of Fallot 被引量:9
11
作者 ZHANG Hong-shan WU Qing-yu +2 位作者 XU Ming ZHOU Yu-xiang SHUI Chao-xiang 《Chinese Medical Journal》 SCIE CAS CSCD 2012年第13期2243-2249,共7页
Background Tetralogy of Fallot (TOF) is the most common malformation of children with an incidence of approximately 10% of congenital heart disease patients. There can be a wide spectrum to the severity of the anato... Background Tetralogy of Fallot (TOF) is the most common malformation of children with an incidence of approximately 10% of congenital heart disease patients. There can be a wide spectrum to the severity of the anatomic defects, which include ventricular septal defect, aortic override, right ventricular outflow tract obstruction, and right ventricular hypertrophy. We examined the relationship between right ventricular hypertrophy in patients with TOF and the gene expression of factors in the mitogen-activated protein kinase (MAPK) signal pathway. Methods To gain insight into the characteristic gene(s) involved in molecular mechanisms of right ventricular hypertrophy in TOF, differential mRNA and micro RNA expression profiles were assessed using expression-based micro array technology on right ventricular biopsies from young TOF patients who underwent primary correction and on normal heart tissue. We then analyzed the gene expression of the MAPK signal pathway using reverse transcription-polymerase chain reaction (RT-PCR) in normals and TOF patients. Results Using the micro RNA chip V3.0 and human whole genome oligonucleotide microarray VI.0 to detect the gene expression, we found 1068 genes showing altered expression of at least two-fold in TOF patients compared to the normal hearts, and 47 micro RNAs that showed a significant difference of at least two-fold in TOF patients. We then analyzed these mRNAs and micro RNAs by target gene predicting software Microcosm Targets version 5.0, and determined those mRNA highly relevant to the right ventricular hypertrophy by RT-PCR method. There were obvious differences in the gene expression of factors in the MAPK signal pathway when using RT-PCR, which was consistent to the results of the cDNA microarray.Conclusion The upregulation of genes in the MAPK signal pathway may be the key events that contribute to right ventricular hypertrophy and stunted angiogenesis in patients with TOF. 展开更多
关键词 tetralogy of Fallot gene expression heart development mitogen-activated protein kinases MICROARRAY micro RNA mRNA Conclusion The upregulation of genes in the MAPK signal pathway may be the key events that contribute to rightventricular hypertrophy and stunted angiogenesis in patients with TOF.
原文传递
不同种植方式和密度对玉米子粒灌浆速率的影响 被引量:8
12
作者 付健 杨克军 +9 位作者 王玉凤 张翼飞 赵莹 谷英楠 杨系玲 刘慧迪 张发明 刘承 刘瑀 方永江 《湖北农业科学》 北大核心 2014年第18期4272-4275,共4页
以紧凑型品种郑单958为试验材料,在2种不同种植形式(传统小垄、大垄双行)和不同播种方式(一穴单株和一穴双株)及4种种植密度(6.0万、7.5万、9.0万、10.5万株/hm2)条件下,研究不同种植方式和密度对玉米(Zea may L.)光合特性、子粒干重及... 以紧凑型品种郑单958为试验材料,在2种不同种植形式(传统小垄、大垄双行)和不同播种方式(一穴单株和一穴双株)及4种种植密度(6.0万、7.5万、9.0万、10.5万株/hm2)条件下,研究不同种植方式和密度对玉米(Zea may L.)光合特性、子粒干重及灌浆速率的影响。结果表明,大垄双行比传统小垄更能创建有利的群体结构,改善植株间的竞争关系,提高子粒灌浆速率。一穴双株在低密度下表现较好。不同种植密度对玉米光合特性、子粒干重及灌浆速率的影响随种植密度的增加呈下降趋势。种植方式和密度间的互作达极显著水平,说明在适宜的种植密度下,合理的种植方式可以改善群体结构,合理分配光资源。其中,低密度条件下种植方式C表现较好,高密度条件下种植方式E的光合能力保持较高水平,对提高子粒的干重和灌浆速率有显著影响。 展开更多
关键词 玉米(Zea may L.) 种植方式 种植密度 光合特性 灌浆速率
下载PDF
对刑法中“可以”的思考 被引量:6
13
作者 张庆旭 《燕山大学学报(哲学社会科学版)》 2003年第1期85-89,共5页
刑法规范模式中使用了大量的、带有两可倾向含义的“可以”,使得法律中的“可以”之行为就有了“可以为”和“可以不为”的两种选择,这就为司法实践带来了一定的难度。本文从“可以”的逻辑内涵入手,考察了刑法中“可以”存在的问题。
关键词 刑法 行为 可以 可以不 不确定
下载PDF
2022年5月广东气温异常偏低的气候特征及其成因 被引量:1
14
作者 谢洁宏 胡娅敏 叶梦茜 《广东气象》 2024年第1期19-22,27,共5页
基于NCEP/NCAR再分析数据集、NOAA海温和向外长波辐射以及国家气象观测站平均气温数据,采用线性趋势、合成分析方法,探讨2022年5月广东气温异常偏低的气候特征及其成因。结果表明,2022年5月平均气温较常年低1.9℃,创下广东1961年以来最... 基于NCEP/NCAR再分析数据集、NOAA海温和向外长波辐射以及国家气象观测站平均气温数据,采用线性趋势、合成分析方法,探讨2022年5月广东气温异常偏低的气候特征及其成因。结果表明,2022年5月平均气温较常年低1.9℃,创下广东1961年以来最低值;该次异常低温是在拉尼娜事件背景下发生的,通过大气环流对欧亚大陆气候产生显著性影响;欧亚中高纬环流经向度偏大,东亚大槽与蒙古高压偏强,引导东西伯利亚及其以北地区过多的冷空气向南侵袭,同时低纬活跃的偏南暖湿气流与北方冷空气在广东上空交汇致雨成云,地表非绝热加热与大气下沉增温效应受抑制,进而导致了2022年5月的气温异常偏低。 展开更多
关键词 气候学 异常低温 环流异常 拉尼娜事件(La Ni1a) 5月 广东省
下载PDF
海南省1株甲属虫媒病毒的分离鉴定及其血清抗体调查 被引量:7
15
作者 蒋廉华 赵春生 +7 位作者 徐春华 陈焕勇 方美玉 刘金华 陈唯军 班武 陆振豸 饶颐年 《中国兽医学报》 CAS CSCD 北大核心 1999年第6期549-551,共3页
1995 年,从海南省捕获的蚊虫标本中,分离到1 株病毒,编号为HYM1。该病毒以脑内感染的方式感染2~3 日龄乳鼠及3 周龄小鼠,感染后2~4 d 规律致死。在Vero-E6 细胞组织培养中可增殖,并可产生明显的病变。经理化和生物学鉴定,该病毒对酸... 1995 年,从海南省捕获的蚊虫标本中,分离到1 株病毒,编号为HYM1。该病毒以脑内感染的方式感染2~3 日龄乳鼠及3 周龄小鼠,感染后2~4 d 规律致死。在Vero-E6 细胞组织培养中可增殖,并可产生明显的病变。经理化和生物学鉴定,该病毒对酸、乙醚均敏感,抵抗5-氟脱氧尿苷和胰酶,属RNA 病毒。血清学鉴定表明,该病毒与马雅罗病毒(MAY)抗原性关系密切。从当地人血清中检到了HYM1 病毒抗体,其阳性率为3.99% 。 展开更多
关键词 马雅罗病毒 分离鉴定 血清抗体调查
下载PDF
科技名篇《As We May Think》解读 被引量:4
16
作者 徐跃权 于宁 《图书馆杂志》 CSSCI 北大核心 2006年第11期11-14,共4页
对V.布什的科技名篇《AsWeMayThink》的篇名汉译情况进行分析和总结,给出新译法《我们可以这样设想》及理由;剖析该文的主题内容;就其在图书馆学、情报学、信息管理、以及计算机领域的科学地位与影响做出客观评价。
关键词 题名翻译 主题内容 学科地位 图书馆学 信息管理 计算机科学 V.布什 科技名篇 《As WE may Think》 解读 情报学
下载PDF
Wormhole solutions under the effect of dark matter in f(R,L_(m))gravity
17
作者 Lakhan V Jaybhaye Moreshwar Tayde PK Sahoo 《Communications in Theoretical Physics》 SCIE CAS CSCD 2024年第5期102-113,共12页
In the background of f(R,L_(m))gravity,this work investigates three distinct dark matter halo profiles to test the possibility of generalised wormhole geometry within the galactic halo regions.The current study aims t... In the background of f(R,L_(m))gravity,this work investigates three distinct dark matter halo profiles to test the possibility of generalised wormhole geometry within the galactic halo regions.The current study aims to accomplish these goals by examining various dark matter profiles including universal rotation curves(URC),Navarro-Frenk-White(NFW)model-Ⅰ,and NFW model-Ⅱinside two distinct f(R,L_(m))gravity models.According to the f(R,L_(m))=R/2+L^(a)_(m)model,the dark matter(DM)halo density profiles produce suitable shape functions that meet all the necessary requirements for exhibiting the wormhole geometries with appropriate choice of free parameters.In addition,to examine DM profiles under the f(R,L_(m))=R/2+(1+λR)L_(m) model,we consider a specific shape function.Further,we observed that the derived solution from both two models violates the null energy constraints,confirming that the DM supports wormholes to maintain in the galactic halo. 展开更多
关键词 f(R L_(m))gravity WORMHOLE dark matter(Some figures may appear in colour only in the online journal)
原文传递
2015年5月广东降水异常偏多的成因分析 被引量:6
18
作者 王娟怀 胡娅敏 杨守懋 《广东气象》 2016年第1期4-7,共4页
利用广东省2015年86个台站的降水观测资料,采用小波分析、相关分析、合成分析等方法分析了2015年5月广东省的降水时空特征;并采用NCEP/NCAR再分析资料中的500 h Pa高度场资料,以及国家气候中心气候监测室提供的130项环流指数对降水场进... 利用广东省2015年86个台站的降水观测资料,采用小波分析、相关分析、合成分析等方法分析了2015年5月广东省的降水时空特征;并采用NCEP/NCAR再分析资料中的500 h Pa高度场资料,以及国家气候中心气候监测室提供的130项环流指数对降水场进行分析。结果发现:广东省2015年5月的降水除了雷州半岛、粤东部分地区,其余大部分地区较常年异常偏多,为有气象记录以来历史同期最多。造成该月降水偏多的主要原因是受ENSO信号的影响;5月环流形势由前期的纬向型向经向型的转型,500 h Pa高度场在内蒙古北部、东北上空及日本海地区存在一个正-负-正的偶极子模型,同时配有来自南海充足的水汽条件,从而造成5月降水异常偏多。 展开更多
关键词 气候学 降水 5月 ENSO信号 环流形势 广东省
下载PDF
山楂叶片气孔的研究Ⅰ.不同生物学因素和土壤条件下叶片的气孔特征 被引量:3
19
作者 关军锋 张彦武 +3 位作者 冯振斌 裴贵 高林森 刘雅哲 《河北农业技术师范学院学报》 1995年第3期6-9,共4页
研究了不同品种、树龄、树势、枝梢、冠位、土壤条件下山楂树叶片气孔特征的差异性,并对叶片气孔的面积、频度与相对面积的关系做了分析。
关键词 山楂 叶片气孔 生物学特征 土壤
下载PDF
The Influence of Climate Variability on the Watermelon Production in Zanzibar
20
作者 Asya Omar Hamad Kombo Hamad Kai +5 位作者 Agnes Kijazi Sara Abdalla Khamis Abdalla Hassan Abdalla Hassan Khatib Ame Masoud Makame Faki Faki Ali Ali 《Atmospheric and Climate Sciences》 CAS 2023年第1期44-61,共18页
Climate change and variability, has embarked societies in Zanzibar to rely on horticulture (i.e. watermelon production) as an adaptive measure due to an unpromising situation of commonly used agricultural yields. Curr... Climate change and variability, has embarked societies in Zanzibar to rely on horticulture (i.e. watermelon production) as an adaptive measure due to an unpromising situation of commonly used agricultural yields. Currently, there is either no or scant information that describes the influence of climate changes and variability to watermelon production in Zanzibar. Thus, this study aimed to determine the influence of climate variability on the quantity of watermelon production in Zanzibar. The study used both primary and secondary datasets, which include the anecdotal information collected from interviewers’ responses from four districts of Unguja and Pemba, and climate parameters (rainfall, maximum and minimum temperature (Tmax and Tmin) acquired from Tanzania Meteorological Authority (TMA) at Zanzibar offices. Pearson correlation was used for analyzing the association between watermelon production and climate parameters, while paired t-test was applied to show the significance of the mean differences of watermelon and climate parameters for two periods of 2014-2017 and 2018-2021, respectively. Percentage changes were used to feature the extent to which the two investigated parameters affect each other. The anecdotal responses were sorted, calculated in monthly and seasonal averages, plotted and then analyzed. Results have shown a strong correlation (r = 0.8 at p ≤ 0.02, and r = 0.7) between watermelon production, Tmax and rainfall during OND, especially in Unguja, as well as Tmin during JJA (i.e. r = - 0.8 at p ≤ 0.02) in Pemba. Besides, results have shown the existence of significant differences between the means of watermelon production and climate parameter for the two stated periods, indicating that the climate parameters highly affects the watermelon production by either enhancing or declining the yields by 69% - 162% and 17% - 77%, respectively. Moreover, results have shown that respondents were aware that excess temperature intensity during dry periods can lead to high production costs due number of 展开更多
关键词 WATERMELON March to may (MAM) and October to November (OND) Seasonal Rainfall Maximum and Minimum Temperature Anecdotal Information
下载PDF
上一页 1 2 175 下一页 到第
使用帮助 返回顶部