共查询到20条相似文献，搜索用时 46 毫秒
1.
2.
奥巴马政府2011年1月即将面对共和党领导的众议院,日前,总统科学顾问JohnHoldren就广泛话题接受了美国地球物理联合会（AGU）会刊Eos的独家专访。在此之前,他曾在2010年12月13日旧金山举行的AGU秋季会议上发表过政策演讲。 相似文献
3.
2009年11月15日,美国总统奥巴马首次访华,中美签署了《中美关于在页岩气领域开展合作的谅解备忘录》。以此为契机,中国页岩气的基础研究上升到了国家层面。 相似文献
4.
5月21日,在俄罗斯总统普京访华期间,中国与俄罗斯天然气工业股份公司（Gazprom）在上海签署了《中俄东线供气购销合同》。根据合同,从2018年起,俄罗斯开始通过中俄天然气管道东线向中国供气,输气量逐年增长,最终达到每年380亿立方米,累计合同期30年,总价或超过4000亿美元。 相似文献
5.
6.
2010年12月17日,白宫发布了公众期待已久的奥巴马政府的科研诚信政策指南。美国总统科学顾问(Presidential Science Advisor),同时也是白宫科技政策办公室(White House Office of Science and Tech-nology Policy,OSTP)主任的John Holdren发布了该指南。据他介绍,美国联邦政府各 相似文献
7.
亲爱的总统先生：
我代表世界最大的多学科协会——美国科学促进协会（the American Association for the Advancement of Science,AAAS）给您写这封信,以表示对近期被拉奎拉地方检察官起诉的6位科学家和1位政府官员的事件的关注。起诉这些科学家的控告是不公平的,也是幼稚的。控告根据显示,科学家们未能针对即将发生的地震向公众发出预警。然而,他们无法可靠地预测地震。 相似文献
8.
2009年11月15日,美国总统奥巴马首次访华,中美签署了《中美关于在页岩气领域开展合作的谅解备忘录》。以此为契机,中国页岩气的基础研究上升到了国家层面。在此之前,2009年8月17日,国土资源部油气资源战略研究中心会同中国地质大学(北京)等单位在重庆市綦江县、巫溪县启动了全国首个页岩气资源勘探项目。页岩气开发从綦江起步,走向全国。 相似文献
9.
自从理查德·尼克松1973年承诺要实现能源独立以来,历届美国总统都会把这个目标挂在嘴边。然而事实却是,能源进口的比例越来越大,美国离这个目标也越来越远。如今,距尼克松提出能源独立已过去40余年,在能源独立这个目标就快成为一个"空头支票"的时候,美国迎来了那场席卷全球页岩气革命,这似乎是其实现能源独立的大好机会。 相似文献
10.
有人会告诉你总统的预算要求还不如打印纸值钱 ,而它们确实被打印在很多纸上。当总统来自一个政党 ,而国会被另一个政党控制的时候 ,似乎特别能验证这种观点 ,就如同过去5年来的情况那样。还可以有把握地说 ,总统竞选的影响对政府的行政机构和立法机构之间的财政协调并不会有太大的帮助。国会议员会立即考虑总统的要求 ,并在提出他们自己的预算方案之前 ,以压倒的多数否决总统的预算要求 ,就是对上述观点的证明但如果国会众议院和参议院中的任何一方都缺少以多数票否决的证据 ,那就要按照预算中的传统做法 ,经反复论证集中 ,对总统和国会最… 相似文献
11.
阪神·淡路大震灾后 ,日本着手对原有的地震观测体制作彻底改革 ,多项全国性配置地震计的计划同时开始启动。地震引起的地面晃动的程度不尽相同 ,无感微小地震引发的晃动仅有 0 .0 0 1 μm,频率为1 0 Hz;巨大地震引起的地面晃动的幅度高达 2～ 3 m,周期也有几十秒。虽说都称之为地震计 ,但由于地震动的振幅和频率涉及的范围太大 ,所以应针对观测对象选用不同类型的地震计。下面介绍不同类型的观测网。1 强震观测网 ( K- NET)无论大地有多大的晃动都能将其准确记录下来的地震计称之为强震计。它构造坚实 ,信号明确 ,通常设置在地表 ,对了… 相似文献
12.
13.
Michael O. Garcia Diane Hanano Ashton Flinders Dominique Weis Garrett Ito Mark D. Kurz 《Bulletin of Volcanology》2012,74(6):1445-1463
The size, shape, and magmatic history of the most recently discovered shield volcano in the Hawaiian Islands, Mahukona, have been controversial. Mahukona corresponds to what was thought to be a gap in the paired sequence (Loa and Kea trends) of younger Hawaiian volcanoes (<4?Ma). Here, we present the results of marine expeditions to Mahukona where new bathymetry, sidescan sonar, gravity data, and lava samples were collected to address these controversies. Modeling of bathymetric and gravity data indicate that Mahukona is one of the smallest Hawaiian volcanoes (～6,000?km3) and that its magmatic system was not focused in a long-lived central reservoir like most other Hawaiian volcanoes. This lack of a long-lived magmatic reservoir is reflected by the absence of a central residual gravity high and the random distribution of cones on Mahukona Volcano. Our reconstructed subsidence history for Mahukona suggests it grew to at least ～270?m below sea level but probably did not form an island. New 40Ar–39Ar plateau ages range from 350 to 654?ka providing temporal constraints for Mahukona’s post-shield and shield stages of volcanism, which ended prematurely. Mahukona post-shield lavas have high 3He/4He ratios (16–21?Ra), which have not been observed in post-shield lavas from other Hawaiian volcanoes. Lava compositions range widely at Mahukona, including Pb isotopic values that straddle the boundary between Kea and Loa sequences of volcanoes. The compositional diversity of Mahukona lavas may be related to its relatively small size (less extensive melting) and the absence of a central magma reservoir where magmas would have been homogenized. 相似文献
14.
15.
In this study, we have checked the location and focal depth of the Yecheng earthquake (m b = 6.0, maximum intensity VII) of February 14, 1980. The result shows that this is an intermediate event with a focal depth of 90 km. The microepicenter is located at 36. 4°N, 76, 9°E, while the macroepicenter is at 37.3°N, 76.9°E, 90 km to the north of the microepicenter. This is the first destructive intermediate event in China which led to a damage as severe as of intensity VII. The focal mechanism of the event is determined to be of thrust type. Combined with the analysis of seismological and geological data in surrounding area, the possible relation between the event and plate movement has been discussed. The result in this paper indicates that in some particular place, the destructive effect of intermediate event should be considered in seismic hazard assessment. 相似文献
16.
17.
In this study, we experimentally established the relationship between physical properties, vitrinite reflectance, and microstructure of coal, Taiyuan Formation, Qinshui Basin, China using representative coal samples collected from three different mines via the rock mechanics testing system (MTS). We analyzed the organic macerals, vitrinite reflectance, and microstructure of 11 coal samples using petrography and scanning electron microscopy (SEM). The experimental results suggest that (1) the elastic parameters can be described by linear equations, (2) both P-and S-wave velocities display anisotropy, (3) the anisotropy negatively correlates with vitrinite reflectance, and (4) the acoustic velocities and Young’s modulus are negatively correlated with the volume of micropores. The derived empirical equations can be used in the forward modeling and seismic inversion of physical properties of coal for improving the coal-bed methane (CBM) reservoir characterization. 相似文献
18.
Sun, climate, hunger, and mass migration 总被引：9，自引：1，他引：8
Kenneth J. Hsu 《中国科学D辑(英文版)》1998,41(5):449-472
Paleoclimatic studies indicate four epochs of global cooling during the last 4 000 years, i. e. during the few centuries before
and after 2000 BC, 800 BC, 400 AD, and 1 600 AD; the quasiperiodicity corresponds to cyclic variation of solar activity. Global
temperature changes influenced regional precipitation patterns: Northern Europe was wetter while the middle- and low-latitude
lands were more arid during colder epochs. Both sets of cold climatical conditions were unfavorable for agricultural production.
Historical records show that large demographic movements in history took place because of crop failures and mass starvation,
rather than escaping from war zones. The “wandering” of the Germanic tribes during the first two or three centuries of the
Christian Era is one example. Whereas the accelerated release of carbon dioxide from the burning of fossil fuels is ultimately
to cause global warming, historical evidence indicates, however, that global warming has been on the whole a blessing to mankind.
Global cooling, on the other hand, has curtailed agricultural production and has led to famines and mass migrations of people.
Perhaps the most important task at the present is not so much computer-modelling of greenhouse effect on global climate, but
water-management and agricultural researches to insure food-supply for an everincreasing world population. 相似文献
19.
Abu Sayeed Shafiuddin Ahmed Mohammad Belal Hossain Saad Mohammad Omar Faruque Babu Moshiur Rahman Jun Sun Mohammad Shafiqul Islam Sarker 《国际泥沙研究》2022,37(1):83-96
Sediment samples from the Gomti River basin were investigated to determine and evaluate trace metal concentrations,their biological effect,and potential ecological and human health risks for adults and children.The mean concentrations of trace metals were organized in the descending order of mercury(Hg)(0.08 mg/kg)>chromium(Cr)(0.06 mg/kg)>lead(Pb)(0.05 mg/kg)>arsenic(As)(0.02 mg/kg)>cadmium(Cd)(0.01 mg/kg).The current study illustrated that metals were attributed to the area from natural sources and different anthropogenic sources especially from industries.However,the concentration levels were lower than the sediment quality guidelines(SQGs)based on the effect-range classifications of threshold effect concentration(TEC)and probable effect concentration(PEC).Therefore,the concentration of the elements showed no adverse biological effects on aquatic organisms.The evaluated potential ecological risk index also revealed the low toxicity to the aquatic environment.Moreover,the applied sediment quality indices,geo-accumulation index(Igeo),contamination factor(CF),and contamination severity index(CSI)suggested that the contamination levels of the elements were in the acceptable range,and the contamination had not notably impacted on the sediment quality.The risk index(HI)concerning age groups was significantly less than the threshold limit of 1 indicating that the contamination had no non-carcinogenic risk effect.The total carcinogenic risk(TCR)was less than a risk value of 1×104.Hence,the current study suggests that immediate remediation is not required due to an absence of alarming conditions in the study area.Proper monitoring of the attribution of the metal elements should be done for the betterment of human and environmental health。 相似文献