Generation of Interstellar Class Ⅱ 72-81A and 72-81A-Methanol Masers     

Han-Ping Liu  Jin Sun Department of Physics  Beijing Normal University  Beijing  Department of Astronomy  Beijing Normal University  Beijing 《中国天文和天体物理学报》2007,7(6):803-808

New methanol maser lines at 72 → 63A-(86.6GHz) and 72 → 63A (86.9GHz) together with two candidate methanol maser lines at 72 → 81A-(80.99GHz) and 72 → 81A (111.29GHz) have been detected in W3(OH). We use a pumping mechanism,i.e.,methanol masers without population inversion,to explain the formation of weak methanol masers of 72 → 81A and 72 → 81A-. We explain well why the line-shape of the transition 72 → 81A is not typical. A similar argument can be applied to the Λ-type level system 72A-,63A-and 81A-,as well as to the 72 → 81A-80.99GHz masers.  相似文献   

Generation of Interstellar Class Ⅱ 72-81A+ and 72-81A-Methanol Masers     

Han-Ping Liu  Jin Sun 《中国天文和天体物理学报》2007,7(6)

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缺少深度睡眠将增大Ⅱ型糖尿病的风险     

《海洋世界》2008,(3):8-8

深度睡眠也称为“短波睡眠”。它是整个睡眠过程最有助于身体恢复良好状态的阶段。最近，来自芝加哥大学医学中心的研究者发现，当健康的年轻人有3个晚上的深度睡眠受到抑制时。他们的身体对胰岛素的敏感性就会降低。对血糖水平的调节能力将显著下降。这时，他们的身体需要更多的胰岛素来分解体内的葡萄糖，从而导致身体对葡萄糖的耐受性降低，增大了Ⅱ型糖尿病的风险。  相似文献   

辽宁省地震重点监视防御区Ⅱ类场地放大效应研究     

王超  王辉  靳超宇  肖遥 《防灾减灾学报》2014,(2):1-5

利用辽宁省地震重点监视防御区工程场地地震安全性评价工作中积累的大量实际钻孔和土工试验资料,在50年超越概率为63%、10%、2%三种地震动输入情形下,采用等效线性化方法研究了辽宁省地震重点监视防御区Ⅱ类场地土层的放大效应。研究结果表明辽宁省地震重点监视防御区50年超越概率10%的平均场地效应放大因子为1.37,若使用《中国地震动参数区划图（GB18306-2001）》认定的系数（1.25）将低估研究区域内的场地放大效应。50年超越概率2%情形即＂工程结构抗倒塌水准＂的平均场地放大效应因子为1.35。这些结果有益于为研究区域提供更为合理的抗震设防标准。研究同时发现,实际工程中使用单一变量或有限的几个变量去控制场地放大效应会有很大的离散,因此重大工程项目的地震安全性评价工作是不可被替代的。  相似文献   

高原地区云对地闪电首次回击的光谱研究   总被引：7，自引：1，他引：6       下载免费PDF全文

袁萍  刘欣生  张义军  郄秀书  张广庶  王怀斌 《地球物理学报》2004,47(1):42-46

用无狭缝光栅摄谱仪,获得了青海西宁地区云对地闪电首次回击过程400～700nm波 长范围的光谱,并首次在闪电的单次回击光谱中记录到了波长为604.6nm和619.4nm的谱线. 将原子结构的理论应用于闪电光谱的研究,用多组态Dirac Fock方法,计算了有关光谱线 的 波长、振子强度以及相应的激发态能量等参数,理论与试验观测资料进行比较分析后发现, 高原地区闪电首次回击光谱的结构及跃迁特性与其他地区有明显的区别,除NII离子n=3 的低 激发态产生的跃迁谱线外,激发能量为13～14eV左右的中性NI和OI的跃迁增多,但很难观测 到OII离子的跃迁谱线.  相似文献   

赣南侏罗世玄武岩的Pb-Nd-Sr同位素地球化学研究:中生代地幔源区特征及构造意义     

《高校地质学报》2004,10(2)

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TJ-Ⅱ型钻孔应变仪安装过程中的几个技术问题     

李希亮  苏恺之  李海亮  李栋梁  王纪强  冯恩国 《大地测量与地球动力学》2013,(Z2):142-144

根据山东省TJ-Ⅱ型钻孔应变仪的安装经验,简要讨论了TJ-Ⅱ型钻孔应变仪在安装过程中要注意的几个技术问题。  相似文献   

Mutations in exons of the CYP17-II gene affect sex steroid concentration in male Japanese flounder (Paralichthys olivaceus)     

Ruiqin Ma  Feng He  Haishen Wen  Jifang Li  Bao Shi  Dan Shi  Miao Liu  Weijie Mu  Yuanqing Zhang  Jian Hu  Weiguo Han  Jianan Zhang  Qingqing Wang  Yuren Yuan  Qun Liu 《中国海洋大学学报(英文版)》2012,11(1):99-104

As a specific gene of fish,cytochrome P450c17-Ⅱ(CYP17-Ⅱ) gene plays a key role in the growth,development and reproduction level of fish.In this study,the single-stranded conformational polymorphism(SSCP) technique was used to characterize polymorphisms within the coding region of CYP17-Ⅱ gene in a population of 75 male Japanese flounder(Paralichthys olivaceus).Three single nucleotide polymorphisms(SNPs) were identified in CYP17-Ⅱ gene of Japanese flounder.They were c.G594A(p.G188R),c.G939A and c.G1502A(p.G490D).SNP1(c.G594A),located in exon 4 of CYP17-Ⅱ gene,was significantly associated with gonadosomatic index(GSI).Individuals with genotype GG of SNP1 had significantly lower GSI(P < 0.05) than those with geno-type AA or AG.SNP2(c.G939A) located at the CpG island of CYP17-Ⅱ gene.The mutation changed the methylation of exon 6.Indi-viduals with genotype AA of SNP2 had significantly lower serum testosterone(T) level and hepatosomatic index(HSI) compared to those with genotype GG.The results suggested that SNP2 could influence the reproductive endocrine of male Japanese flounder.How-ever,the SNP3(c.G1502A) located in exon 9 did not affect the four measured reproductive traits.This study showed that CYP17-Ⅱ gene could be a potentially useful candidate gene for the research of genetic breeding and physiological aspects of Japanese flounder.  相似文献   

漳州地震台TJ-Ⅱ型体应变观测初析     

张凯  林苗禄  谢雄魁  方宏芳 《地震地磁观测与研究》2012,33(3):210-213

通过对漳州地震台TJ-Ⅱ型体应变资料的映震效应分析,并利用多种方法对形变前兆异常分析,探讨区域地下形变资料对地震短临预报的实际意义。  相似文献   

Effects of waterborne Fe(II) on juvenile turbot Scophthalmus maximus: analysis of respiratory rate, hematology and gill histology     

��־�  �ȷ�  �����  ������  ���  ����� 《中国海洋湖沼学报》2012,30(2):193-199

The concentration of Fe(Ⅱ) is high in some groundwater supplies used in turbot culture,and the toxicity of waterborne Fe(Ⅱ) is unknown.We investigated the stress responses of juvenile turbot,Scophthalmus maximus,exposed to Fe(Ⅱ) of different concentrations (0.01,0.05,0.1,0.5,1,and 2 mg/L) for 1,7,14,and 28 d,under the same ambient conditions of other parameters.Changes in respiratory rate,hematological parameters,and gill structure were determined.The results show that waterborne Fe(Ⅱ) did not cause severe hematological perturbation to turbot.A low-medium Fe(Ⅱ) concentration (lower than 0.1 mg/L) could boost the respiratory rate,and caused no or very limited damage to fish.A high Fe(Ⅱ) concentration (0.1 mg/L or higher),however,caused gill damage,such as vacuoles in branchial lamellae,epithelial necrosis,and hypertrophy of epithelial cells,and even death after extended exposure time.Therefore,excess waterborne Fe(Ⅱ) and long-term exposure to Fe(Ⅱ) could be responsible for poor growth and high mortality of turbot in culture.The concentration of waterborne Fe(Ⅱ) in turbot culture should be kept below 0.1 mg/L.  相似文献