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11.
本文报告了文昌鱼酸性磷酸酯酶在不同浓度的盐酸胍作用下酶的构象与催化活力变化的关系。盐酸胍浓度在1mol/dm~3时,酶活力提高50%.随着盐酸胍浓度提高(2~4mol/dm~3),酶活力下降,荧光强度也下降,荧光发射光谱λ_(max)值明显红移(330~358nm)。测其变性及失活动力学常数,结果表明,酶的失活速度大于变性速度,表现为慢构象变化、快活力变化的一种模式。在盐酸胍3~4mol/dm~3时,酶的变性与失活过程表现为两个一级反应过程(快相和慢相),其构象与催化活力的变化表明AC-Pase 与活力部位相关的色氨酸残基微环境产生了变化。 相似文献
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我省气象业务体系在9210工程之后,已显示出预报体制和流程不适应新的设备与技术环境的问题,影响了天气预报业务技术的发展,制约了天气在空间,时间分辨率方面的提高,因此,如何在卫星广域网高速舆网络环境下,建立一套新的预报业和作用流程以及省,地,县三级预报技术,是非常重要的。 相似文献
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长毛对虾酸性磷酸酶功能基团的研究(Ⅱ) 总被引:1,自引:0,他引:1
用化学修饰剂pCMB、NBS、K试剂修饰长毛对虾Penaeuspenicilla-tusAlcock酸性磷酸酶(ACPase,EC3.1.3.2),在修饰剂作用下,酶活力明显下降,健康虾酶对修饰剂的敏感性(NBS除外)大都稍大于病虾酶。修饰酶的紫外280um吸收光谱以及荧光340um发射光谱的变化,表明酶活力下降的同时酶构象也产生相应的变化。结果表明,酶分子的半胱氨酸残基、色氨酸残基以及门冬氨酸、谷氨酸β或γ验基与酶活力有关,是酶的催化功能基团。 相似文献
16.
Depths of earthquake occurrence and large slip distribution are critical for seismic hazard assessment.Numerous examples show that earthquakes with similar magnitudes,however,can result in significantly different ground shaking and damage.One of the critical factors is that whether the large slip was generated near the ground surface.In this article,we reviewed two aspects that are important on this regard,shallow slip deficit and nucleation depth.Understanding how shallow future earthquakes may nucleate in particular regions,such as shale gas fields,is critical for hazard assessment.Whether or not a strong earthquake may slip significantly at shallow depths(less than 3 km)plays crucial rules in seismic hazard preparation and should be further investigated by integrating high-resolution fault zone observations,dynamic rupture simulation,and fault zone properties.Moreover,precisely resolving shallow depth and slip distribution of earthquakes demands InSAR and/or other image data that can better capture the near-fault deformation to constrain the source parameters of earthquakes. 相似文献
17.
Evaluating historical simulations of CMIP5 GCMs for key climatic variables in Zhejiang Province,China 总被引:1,自引:0,他引:1
Weidong?Xuan Chong?Ma Lili?Kang Haiting?Gu Suli?Pan Yue-Ping?XuEmail author 《Theoretical and Applied Climatology》2017,128(1-2):207-222
Assessing the regional impact of climate change on agriculture, hydrology, and forests is vital for sustainable management. Trustworthy projections of climate change are needed to support these assessments. In this paper, 18 global climate models (GCMs) from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) are evaluated for their ability to simulate regional climate change in Zhejiang Province, Southeast China. Simple graphical approaches and three indices are used to evaluate the performance of six key climatic variables during simulations from 1971 to 2000. These variables include maximum and minimum air temperature, precipitation, wind speed, solar radiation, and relative humidity. These variables are of great importance to researchers and decision makers in climate change impact studies and developing adaptation strategies. This study found that most GCMs failed to reproduce the observed spatial patterns, due to insufficient resolution. However, the seasonal variations of the six variables are simulated well by most GCMs. Maximum and minimum air temperatures are simulated well on monthly, seasonal, and yearly scales. Solar radiation is reasonably simulated on monthly, seasonal, and yearly scales. Compared to air temperature and solar radiation, it was found that precipitation, wind speed, and relative humidity can only be simulated well at seasonal and yearly scales. Wind speed was the variable with the poorest simulation results across all GCMs. 相似文献
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Using data from the Transition Region and Coronal Explorer (TRACE), Solar and Heliospheric Observatory (SOHO), Ramaty High Energy Solar Spectroscopic Imager (RHESSI), and Hida Observatory (HO), we present a detailed study of an EUV jet and the associated Hα filament eruption in
a major flare in the active region NOAA 10044 on 29 July 2002. In the Hα line wings, a small filament was found to erupt out
from the magnetic neutral line of the active region during the flare. Two bright EUV loops were observed rising and expanding
with the filament eruption, and both hot and cool EUV plasma ejections were observed to form the EUV jet. The two thermal
components spatially separated from each other and lasted for about 25 minutes. In the white-light corona data, a narrow coronal
mass ejection (CME) was found to respond to this EUV jet. We cannot find obvious emerging flux in the photosphere accounting
for the filament eruption and the EUV jet. However, significant sunspot decay and magnetic-flux cancelation owing to collision
of opposite flux before the events were noticed. Based on the hard X-ray data from RHESSI, which showed evidence of magnetic
reconnection along the main magnetic neutral line, we think that all of the observed dynamical phenomena, including the EUV
jet, filament eruption, flare, and CME, should have a close relation to the flux cancelation in the low atmosphere. 相似文献
20.
河流水系连通性具有水文调蓄、保障生物迁徙通畅、改善水土环境等功能,目前主要从水文、景观和生态等方面对其进行了定义,而河流水系连通性对社会发展也发挥着重要作用,故河流水系连通性具有自然和社会双重属性,其连通性机制主要表现为纵向、横向、垂向连通性。目前主要从景观学、水文学、水力学、生态学等学科角度提出了图论法、水文-水力学法、景观法、生物法和综合指标法等计算方法,各方法有其适用性和不足,应用中须针对实际问题选择适宜方法或进行修正。河流水系连通性未来研究应综合多尺度、多领域、多学科,在研究内容上,重点开展尺度协同、连通性含义界定、响应机理及修复问题研究,在研究手段上,重点开展多方法、多技术集成问题研究。 相似文献