Magnetic reconnection model for X-ray flare loop interaction

The subtle interactions between the magnetohydrodynamics (MHD) and transverse plasmons are investigated. It is shown that there is a resistive instability by the plasmon's soliton in a current sheet, which eventually turns into an eruptive instability at the magnetic field reconnection. In the case of ion-acoustic turbulence, the high temperature current sheet model must adopt the aromalous conductivity instead of the Coulomb conductivity. The numerical results are consistent with the observations obtained by Hanaoka (1994). Thus the flare caused by X-ray loop coalescence can be basically interpreted by this model of magnetic field reconnection driven by ponderomotive force.     

中国分散元素富集与成矿研究新进展

本文重申了对分散元素种类的界定,将Cd、Ga、In、Tl、Ge、Se、Te和Re 8种元素作为分散元素既兼顾了传统习惯,也考虑到了地球化学性质的异同,同时也考虑了地质事实.近十年来,分散元素大规模的工业利用引发了对分散元素资源的进一步研究,新的研究成果主要包括：①分散元素可以成矿,可以形成独立和共生矿床,可以形成大型甚至超大型矿床,甚至可以形成分散元素矿集区或成矿域,这一新的进展打破了分散元素不能独立成矿的传统观念.在中国已经发现了许多分散元素独立矿床;②分散元素的富集成矿具有矿床类型和矿物类型的专属性,这意味着注意特定的矿床类型,会使找到相应的分散元素矿床的可能性增加;③发现和明确了分散元素的三种主要存在形式即独立矿物、类质同象和吸附,首次在国内矿床中发现了一系列分散元素矿物和新矿物;④Se、Tl、Cd的释放对环境的危害最主要的方式是通过污染饮用水进而影响到人类健康,其它分散元素对环境的作用目前还不十分清楚.     

舟山渔场及邻近海域鱼类种类组成和数量分布

根据2006年8月、2007年1、5、11月在舟山渔场及邻近海域(29°30′—32°00′N,127°E以西)开展海洋生态系统综合调查所获得的游泳动物调查资料,用渔获率作为鱼类资源分布的数量指标,对舟山渔场及邻近海域的鱼类种类组成、数量分布、季节变化趋势作了定量分析。结果表明,舟山渔场及邻近海域鱼类种类约有139种,隶属14目、56科、105属,其中日本红娘鱼、绿鳍鱼、六丝矛尾虎鱼、细条天竺鱼、海鳗、黑、星康吉鳗、小黄鱼、前肛鳗、短吻舌鳎、棘头梅童鱼等25种鱼类占鱼类总渔获量的84.18%,是调查海域桁杆拖网的主要捕捞鱼类,而其它种类的渔获量较少。不同季节的经济鱼类渔获物组成相差较大,而优势种种类组成变化较少。渔获量高峰期主要出现在夏季,从不同区域的渔获率分布趋势来看,春、夏、秋季的鱼类渔获率都以江外渔场最高,其次是长江口渔场,舟山渔场居第三,而杭州湾河口区的鱼类渔获率明显偏低。冬季鱼类渔获率分布趋势与春夏秋季不同,以长江口渔场为最高,其次是舟山渔场,而江外渔场和杭州湾河口区渔获率明显偏低。与以往(20世纪60年代初)调查结果相比,舟山渔场及邻近海域鱼类种数组成、种群动态及群落结构都发生了很大的变化。     

Mid-to-Far Infrared Spectral Energy Distribution of Galaxies in the Spitzer First Look Survey Field

We made model fitting to the mid-to-far infrared spectral energy distributions (SEDs) for different categories of galaxies in the main extragalactic field of the Spitzer First Look Survey with the aid of spectroscopic information from the Sloan Digital Sky Survey. We find that the mid-to-far infrared SEDs of HII galaxies, mixture type galaxies and LINERs can be well fitted by the one-parameter (α) dust model of Dale et al. plus the 13 Gyr dust-free elliptical galaxy model. The statistics of α values indicates that all these galaxies tend to be quiescent, although the HII galaxies are relatively more active than the LINERs. The mid- infrared SEDs of absorption galaxies are well fitted simply by the 13 Gyr dust-free elliptical galaxy template, and the near-to-mid infrared SEDs of QSOs can be represented by AGN NGC 5506.     

Nonsteady interaction of plasma with bodies moving in space

Nonsteady interactions between spacecraft and plasma are investigated in detail. The system of equations describing these interactions is obtained. It is shown that an electromagnetic soliton is excited via the modulational instabilities, which result from the radiation of antenna systems on the body which are the source of waves. In the meantime the density in far wake diminishes, and its disturbance becomes also a soliton if the pump wave is sufficiently intense.     

唐代治乱分期与气候变化的关系*

将唐代定量划分为治世与乱世5个时期,探讨了唐代治乱分期与气候变化的关系。治世、乱世的划分标准参考一套系统的战争数据集,并用单因素方差分析的方法验证各项数据指标在治世与乱世间的差异性,从而说明唐代治世、乱世分期的合理性。治世、乱世分期结果如下: 公元618—626年为乱世,公元627—742年为治世,公元743—784年为乱世,公元785—859年为治世,公元860—907年为乱世。方差分析的结果显示,除了总边境战争外,气候变化、总战争、反叛战争、进攻型边境战争、防御型边境战争、农业丰歉等级和人口增长率在治世与乱世之间均表现出显著差异。用战争定量体现唐代社会治世、乱世变化,探讨气候变化与社会治、乱的关系即是探讨气候变化与战争的关系,乱世的主要战争类型是反叛战争和防御型边境战争,治世的主要战争类型是进攻型边境战争。相关分析结果表明,唐代温度降低、降水减少的时期,农业收成减少导致资源供给不足,更容易发生反叛战争;温度暖期、降水充沛的时期,农业产量提高,刺激了快速增长的人口,在技术改善能力有限、土地资源一定的情况下,更易发生以对外扩张为目的的边境战争,因此气候变化是影响唐代社会治乱变化的重要原因之一。     

2013年四川芦山7.0级地震烈度遥感评估

2013年4月20日四川芦山MS7.0级地震发生后,在灾区应急获取了多种高分辨率航空和无人机遥感影像,并快速解译提取了灾区建筑物震害信息.采用地震烈度遥感定量评估方法,利用2008年汶川8.0级地震等震后震害遥感解译和现场调查研究确定的经验震害遥感定量评估模型,获得了芦山地震灾区126个主要居民点的地震烈度遥感评估结果,并据此圈画了地震烈度分布遥感评估图.结果显示,本次地震Ⅸ度区面积约150km2,Ⅷ度区面积约900km2.该结果在第一时间(4月21日晚)提供给了中国地震局地震现场应急指挥部.对比分析显示,地震烈度遥感快速评估结果与中国地震局4月25日公布的地震烈度图,以及与笔者在现场实地进行的建筑物震害详细调查结果基础上评定的地震烈度具有较高的一致性.表明强烈地震发生后,借助于快速获取的灾区高分辨率遥感影像,可以快速估计地震烈度分布,对地震灾区灾情估计和抗震救灾工作具有十分重要的参考意义.     

The Wenchuan Earthquake (May 12, 2008), Sichuan Province,China, and resulting geohazards

On Monday, May 12, 2008, a devastating mega-earthquake of magnitude 8.0 struck the Wenchuan area, northwestern Sichuan Province, China. The focal mechanism of the earthquake was successive massive rock fracturing 15 km in depth at Yingxiu. Seismic analysis confirms that the major shock occurred on the Beichuan–Yingxiu Fault and that aftershocks rapidly extended in a straight northeast–southeast direction along the Longmenshan Fault zone. Fatalities approaching a total of 15,000 occurred, with a significant number resulting from four types of seismically triggered geohazards—rock avalanches and landslides, landslide-dammed lakes (“earthquake lakes”), and debris flows. China Geological Survey has identified 4,970 potentially risky sites, 1,701 landslides, 1,844 rock avalanches, 515 debris flows, and 1,093 unstable slopes. Rock avalanches and landslides caused many fatalities directly and disrupted the transportation system, extensively disrupting rescue efforts and thereby causing additional fatalities. Landslide-dammed lakes not only flooded human habitats in upstream areas but also posed threats to potentially inundated downstream areas with large populations. Debris flows become the most remarkable geohazards featured by increasing number, high frequency, and low triggering rainfall. Earthquake-triggered geohazards sequentially induced and transformed to additional hazards. For example, debris flows occurred on rock avalanches and landslides, followed by landslide-dammed lakes, and then by additional debris flows and breakouts of the landslide-dammed lakes and downstream flooding. Earthquake-induced geohazards occurred mainly along the fault zone and decreased sharply with distance from the fault. It can be anticipated that post-earthquake geohazards, particularly for debris flows, will continue for 5–10 years and even for as long as 20 years. An integrated strategy of continuing emergency response and economic reconstruction is required. The lesson from Wenchuan Earthquake is that the resulted geohazards may appear in large number in active fault regions. A plan for geohazard prevention in the earthquake-active mountainous areas is needed in advance.     

西北太平洋Ms≥7.8级强震影响我国月季降水场的过程分析

地震与气候变化的关系现已成为一个研究热点.本文根据地球流体力学的长波理论,研究了强震地热涡的长波运动特性;分析了西太平洋M_s≥7.8级强震与我国月降水场的对应关系.研究结果表明,与强震相伴的地热涡尺度超过850 km时,它会向西退行,从而影响我国月季降水场的相应演变.利用上述结果,对2007年我国汛期降水分布进行了预报,实况证明此方法可行.