排序方式: 共有34条查询结果,搜索用时 31 毫秒
11.
12.
Sánchez-Lavega A Orton GS Hueso R García-Melendo E Pérez-Hoyos S Simon-Miller A Rojas JF Gómez JM Yanamandra-Fisher P Fletcher L Joels J Kemerer J Hora J Karkoschka E de Pater I Wong MH Marcus PS Pinilla-Alonso N Carvalho F Go C Parker D Salway M Valimberti M Wesley A Pujic Z 《Nature》2008,451(7177):437-440
The atmospheres of the gas giant planets (Jupiter and Saturn) contain jets that dominate the circulation at visible levels. The power source for these jets (solar radiation, internal heat, or both) and their vertical structure below the upper cloud are major open questions in the atmospheric circulation and meteorology of giant planets. Several observations and in situ measurements found intense winds at a depth of 24 bar, and have been interpreted as supporting an internal heat source. This issue remains controversial, in part because of effects from the local meteorology. Here we report observations and modelling of two plumes in Jupiter's atmosphere that erupted at the same latitude as the strongest jet (23 degrees N). The plumes reached a height of 30 km above the surrounding clouds, moved faster than any other feature (169 m s(-1)), and left in their wake a turbulent planetary-scale disturbance containing red aerosols. On the basis of dynamical modelling, we conclude that the data are consistent only with a wind that extends well below the level where solar radiation is deposited. 相似文献
13.
文章从自由基角度分析了几种常见微量元素对原发性痴呆的诱发与影响,期望能对此病的防治提供一定的理论基础. 相似文献
14.
Prestressed concrete structures are main conformati on for the construction of high way bridges. The quality of prestressed concrete s tructures is mainly affected by the tensile strength of prestressing strand. In order to attain the purpose of economic design and long life span of prestressin g strand, the less relaxation property of strand type is suitable for constructi on and usage. Thus, the research and development of prestressing strand is requi red to reach the goals of high tensile strength and ... 相似文献
15.
本文结合煤矿通风系统的特点、论述了模糊控制算法及其在通风自动化系统中的应用。并由单片计算机实现其控制.分析了实验结果.提出了向自组织方向的深化方案 相似文献
16.
A route to high surface area, porosity and inclusion of large molecules in crystals 总被引:19,自引:0,他引:19
Chae HK Siberio-Pérez DY Kim J Go Y Eddaoudi M Matzger AJ O'Keeffe M Yaghi OM 《Nature》2004,427(6974):523-527
One of the outstanding challenges in the field of porous materials is the design and synthesis of chemical structures with exceptionally high surface areas. Such materials are of critical importance to many applications involving catalysis, separation and gas storage. The claim for the highest surface area of a disordered structure is for carbon, at 2,030 m2 g(-1) (ref. 2). Until recently, the largest surface area of an ordered structure was that of zeolite Y, recorded at 904 m2 g(-1) (ref. 3). But with the introduction of metal-organic framework materials, this has been exceeded, with values up to 3,000 m2 g(-1) (refs 4-7). Despite this, no method of determining the upper limit in surface area for a material has yet been found. Here we present a general strategy that has allowed us to realize a structure having by far the highest surface area reported to date. We report the design, synthesis and properties of crystalline Zn4O(1,3,5-benzenetribenzoate)2, a new metal-organic framework with a surface area estimated at 4,500 m2 g(-1). This framework, which we name MOF-177, combines this exceptional level of surface area with an ordered structure that has extra-large pores capable of binding polycyclic organic guest molecules--attributes not previously combined in one material. 相似文献
17.
Cho YS Chen CH Hu C Long J Ong RT Sim X Takeuchi F Wu Y Go MJ Yamauchi T Chang YC Kwak SH Ma RC Yamamoto K Adair LS Aung T Cai Q Chang LC Chen YT Gao Y Hu FB Kim HL Kim S Kim YJ Lee JJ Lee NR Li Y Liu JJ Lu W Nakamura J Nakashima E Ng DP Tay WT Tsai FJ Wong TY Yokota M Zheng W Zhang R Wang C So WY Ohnaka K Ikegami H Hara K Cho YM Cho NH Chang TJ Bao Y Hedman ÅK Morris AP McCarthy MI;DIAGRAM Consortium;MuTHER Consortium Takayanagi R Park KS Jia W Chuang LM Chan JC Maeda S Kadowaki T Lee JY Wu JY 《Nature genetics》2012,44(1):67-72
We conducted a three-stage genetic study to identify susceptibility loci for type 2 diabetes (T2D) in east Asian populations. We followed our stage 1 meta-analysis of eight T2D genome-wide association studies (6,952 cases with T2D and 11,865 controls) with a stage 2 in silico replication analysis (5,843 cases and 4,574 controls) and a stage 3 de novo replication analysis (12,284 cases and 13,172 controls). The combined analysis identified eight new T2D loci reaching genome-wide significance, which mapped in or near GLIS3, PEPD, FITM2-R3HDML-HNF4A, KCNK16, MAEA, GCC1-PAX4, PSMD6 and ZFAND3. GLIS3, which is involved in pancreatic beta cell development and insulin gene expression, is known for its association with fasting glucose levels. The evidence of an association with T2D for PEPD and HNF4A has been shown in previous studies. KCNK16 may regulate glucose-dependent insulin secretion in the pancreas. These findings, derived from an east Asian population, provide new perspectives on the etiology of T2D. 相似文献
18.
Okada Y Kubo M Ohmiya H Takahashi A Kumasaka N Hosono N Maeda S Wen W Dorajoo R Go MJ Zheng W Kato N Wu JY Lu Q;GIANT consortium Tsunoda T Yamamoto K Nakamura Y Kamatani N Tanaka T 《Nature genetics》2012,44(3):302-306
Obesity is a disorder with a complex genetic etiology, and its epidemic is a worldwide problem. Although multiple genetic loci associated with body mass index, the most common measure of obesity, have been identified in European populations, few studies have focused on Asian populations. Here we report a genome-wide association study and replication studies with 62,245 east Asian subjects, which identified two new body mass index-associated loci in the CDKAL1 locus at 6p22 (rs2206734, P = 1.4 × 10(-11)) and the KLF9 locus at 9q21 (rs11142387, P = 1.3 × 10(-9)), as well as several previously reported loci (the SEC16B, BDNF, FTO, MC4R and GIPR loci, P < 5.0 × 10(-8)). We subsequently performed gene-gene interaction analyses and identified an interaction (P = 2.0 × 10(-8)) between a SNP in the KLF9 locus (rs11142387) and one in the MSTN (also known as GDF8) locus at 2q32 (rs13034723). These findings should provide useful insights into the etiology of obesity. 相似文献
19.
TGFB2 mutations cause familial thoracic aortic aneurysms and dissections associated with mild systemic features of Marfan syndrome 总被引:1,自引:0,他引:1
C Boileau DC Guo N Hanna ES Regalado D Detaint L Gong M Varret SK Prakash AH Li H d'Indy AC Braverman B Grandchamp CS Kwartler L Gouya RL Santos-Cortez M Abifadel SM Leal C Muti J Shendure MS Gross MJ Rieder A Vahanian DA Nickerson JB Michel;National Heart Lung Blood Institute 《Nature genetics》2012,44(8):916-921
A predisposition for thoracic aortic aneurysms leading to acute aortic dissections can be inherited in families in an autosomal dominant manner. Genome-wide linkage analysis of two large unrelated families with thoracic aortic disease followed by whole-exome sequencing of affected relatives identified causative mutations in TGFB2. These mutations-a frameshift mutation in exon 6 and a nonsense mutation in exon 4-segregated with disease with a combined logarithm of odds (LOD) score of 7.7. Sanger sequencing of 276 probands from families with inherited thoracic aortic disease identified 2 additional TGFB2 mutations. TGFB2 encodes transforming growth factor (TGF)-β2, and the mutations are predicted to cause haploinsufficiency for TGFB2; however, aortic tissue from cases paradoxically shows increased TGF-β2 expression and immunostaining. Thus, haploinsufficiency for TGFB2 predisposes to thoracic aortic disease, suggesting that the initial pathway driving disease is decreased cellular TGF-β2 levels leading to a secondary increase in TGF-β2 production in the diseased aorta. 相似文献
20.
利用脉宽调制集成控制电路LM3525研制出一种适用于小型程控交换机的DC-DC、AC变换器,对电路的工作原理进行了分析并给出了实验结果. 相似文献