Pore structure of sheared coals and related coalbed methane     

Huoyin Li  Yujiro Ogawa 《Environmental Geology》2001,40(11-12):1455-1461

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Research on the effect of sludge fertilizer on farmland and the safety of heavy metals in a karst area     

Qinglin Xie  Xuehong Zhang  Dunqiu Wang  Jincheng Li  Yiyong Qin  Yudao Chen 《Environmental Geology》2001,41(3-4):352-357

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A numerical model for Type II supernovae — The collapse stage     

Cong Xu  Zong-wei Li  Yun-zao Ge 《Chinese Astronomy and Astrophysics》1985,9(2):154-158

We use the following numerical model for the collapse stage of a Type II supernova of 15 M_⊙. Our electron capture rate includes the effects of the inverse reaction and the neutron-proton mass difference. This decreases the electron density at the collapse stage and led to rather large values of the maximum inward velocity and of the corresponding mass (Umax = 3.06 × 10⁹cm/s, Mmax=0.76 M_⊙). These larger values are more favourable for the propagation of shock after the rebounce and the triggering-off of a Type-II supernova explosion. For neutrino transport, we use a leakage model and an equilibrium diffusion model, respectively, for the thin and thick stages and a grey atmosphere model to assess the effect of neutrino precipitation on the collapse. We found this effect to be small, the energy precipitation to be not more than 10^?5 the neutrino energy loss and the momentum precipitation not more than 10^?6 the gravitational acceleration.  相似文献   

    

Li Chongyin 《大气科学进展》1993,10(1):41-53

In a simple semi-geostropic model on the equatorialβ-plane, the theoretical analysis on the 30-60 day oscillation in the tropical atmosphere is further discussed based on the wave-CISK mechanism. The convection heat-ing can excite the CISK-Kelvin wave and CISK-Rossby wave in the tropical atmosphere and they are all the low-frequency modes which drive the activities of 30-60 day oscillation in the tropics. The most favorable conditions to excite the CISK-Kelvin wave and CISK-Rossby wave are indicated: There is convection heating but not very strong in the atmosphere and there is weaker disturbance in the lower troposphere. The influences of vertical shearing of basic flow in the troposphere on the 30-60 day oscillation in the tropics are also discussed.  相似文献   

PROPAGATION OF 30—60 DAY LOW FREQUENCY OSCILLATIONS AND THEIR INFLUENCE UPON THE SUBTROPICAL WESTERLIES JET STREAM DURING NORTHERN HEMISPHERE WINTER          下载免费PDF全文

史玉光  李清泉 《Acta Meteorologica Sinica》1996,(2)

Based on daily ECMWF gridpoint data of two winters during 1981—1983 including an ENSOyear,propagation of low frequency oscillations(LFO)during Northern Hemisphere winters andtheir influences upon 30—60 day oscillations of the subtropical jet stream are studied with the sta-tistical methods as complex empirical orthogonal function(CEOF)and so on.Results show that inthe winter of a normal year(1981—1982),30—60 day oscillations in the subtropical zone aremainly in the northern and southern flanks of exit region of jet stream.In the ENSO year(1982—1983),they are mainly in the vicinity of entrance and exit regions of jet stream.Intraseasonalchanges of subtropical jet stream manifested themselves as latitudinal fluctuation or longitudinalprogression or regression of about 40 day period.There are marked differences between propagat-ing passages of low frequency modes responsible for changes of subtropical jet stream in the normalyear(1981—1982)and in the ENSO year(1982—1983).Changes of oscillation amplitude showobvious phases.In general,the one in late winter is stronger than that in early winter,strongestone occurs in February.  相似文献   

On the microwave millisecond spike emission and its associated phenomena during the impulsive phase of large solar flare     

Chun-sheng Li  Qi-jun Fu  Yu-hua Yan  Shu-ying Jiang  Hong-wei Li 《Chinese Astronomy and Astrophysics》1985,9(2):128-133

We propose a model of two acceleration regions, which can explain, on the basis of microwave maser caused by a “hollow-beam” distribution of electrons, the presence of millisecond spikes in the event of 1981 May 16 and their absence in the event of 1981 October 12, and the enhanced continuous emission in the latter. We have also uncovered relations among the features, e.g. the Type III_G, Type IV_DCIM and hard x-ray bursts, that accompany the microwave millisecond spikes during the impulsive phase of a large flare.  相似文献   

The genetic diversity,individual relatedness and possible mating system of an isolated population of the Cyprinid species Megalobrama pellgrini in upper reaches of the Changjiang (Yangtze) River,China     

Wang  Huanshan  Wang  Teng  Li  Wenjing  Liu  Huanzhang 《中国海洋湖沼学报》2019,37(3):1042-1050

Megalobrama pellegrini is a cyprinid fish endemic to upper reaches of the Changjiang(Yangtze) River, China, which is also an important economic species in the local area. In recent years,resources of this species have decreased sharply and its conservation has drawn great attention. In the present study, we collected 120 individuals from the Longxi River, a tributary isolated from the main channel of the Changjiang River, where M. pellegrini is still relatively abundant. Using two different molecular markers, mitochondrial cytochrome b(cyt b) gene, and nuclear microsatellite(simple sequence repeat,SSR), we analyzed the genetic diversity of this isolated population. The results show that sequence genetic diversity was low(H_d:0.290 and P_i: 0.000 77 for cyt b gene),while the SSR genetic diversity was high(H_o:0.824 4±0.147 2,H_e: 0.823 510.145 1). Analysis indicated that this population had experienced a bottleneck,with inbreeding and small effective population size(around 50). Based on SSR data, relatedness analyzing revealed that the 120 samples were grouped into 10 completely independent clusters. It was inferred that the mating system of M. pellegrini was polygamy. We suggested that the low genetic diversity could be induced by the overfishing and inbreeding depression. Therefore, we suggested that the urgent conservation measures should be taken to control the overfishing and give better conditions for the fish to grow and spawn, then to restore population size.  相似文献   

    

Kejie Zhai;Hongyuan Fang;Niannian Wang;Bin Li;Jiaxiu Dong;Binghan Xue; 《国际地质力学数值与分析法杂志》2024,48(4):i-i

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A generalized model for effective thermal conductivity of soils considering porosity and mineral composition     

Li  Kai-Qi  Li  Dian-Qing  Chen  Dar-Hao  Gu  Shi-Xiang  Liu  Yong 《Acta Geotechnica》2021,16(11):3455-3466

Acta Geotechnica - Soils have a variety of mineral compositions. Although a number of thermal conductivity models have been developed for soils, few quantitatively investigated the effect of...  相似文献   

    

Chenxi Du  Xianzhi Ao  Bingxian Luo  Jingjing Wang  Chong Chen  Xin Xiong  Xin Wang  Gang Li 《天文和天体物理学研究(英文版)》2022,(2):29-44

The solar energetic particle(SEP)event is a kind of hazardous space weather phenomena,so its quantitative forecast is of great importance from the aspect of spa...  相似文献