Observational evidence for solar coronal decimetric radio pulsations with very short periods

Using the decimetric (700–1500 MHz) radio spectrometer and the synchronous observational system with high temporal resolution at four frequencies (1420, 2130, 2840 and 4260 MHz) of Yunnan Observatory, two rare events were observed on 2001 June 24 and 1990 July 30. The former was a small radio burst exhibiting pulsations with short periods (about 29, 40 and 100 ms) in the impulsive phase. The latter was a large radio burst, which at 2840 MHz produced radio pulsations with period of about 30 ms. This paper focuses on pulsations with very short periods in the range of 29–40 ms. The mechanism of generation of such pulsations may be modulation of radio radiation by the periodic trains of whistler packets originating in unstable regions of the corona. Alternatively, these pulsations can be attributed to wave-wave non-linear interactions of electrostatic upper hybrid waves driven by beams of precipitating electrons in flaring loops.     

大庆长垣西缘断裂浅部构造特征

大庆石油物探资料结果表明,大庆长垣西缘断裂的上盘,即东侧的北西向断裂可能存在第四纪活动断裂。为了确定大庆长垣西缘断裂的空间展布以及该区的地壳浅部地质构造特征,本项研究布设了2条跨大庆长垣西缘断裂的浅层地震探测剖面。结果表明,大庆长垣西缘断裂表现为走向北东、倾向南东的逆断层,为一条中生代晚期活动断裂。断裂的上盘,即东侧发育有一系列次级断裂,断裂的断层性质以及断层倾向多样化,两条测线东部均发育错断第四纪地层的断层,使得该区浅部地层形成地堑与地垒构造。本项研究不仅可进一步提高对大庆长垣地区浅部构造特征的认识,而且为大庆市地震危险性评价提供依据。     

Marine bacterium strain screening and pyrethroid insecticide-degrading efficiency analysis

A pyrethroid insecticide-degrading bacterium, strain HS-24, was isolated from an offshore seawater environment. The strain, which can degrade cypermethrin(CYP) and deltamethrin(DEL), was identified as Methylophaga sp. The optimal culture and degradation conditions for CYP and DEL by strain HS-24 is pH 7 at 28°C. Under optimum culture conditions, strain HS-24 exhibited a broad degradation concentration range of 100, 200, 400, 600, and 800 mg/L for CYP and DEL. The metabolic intermediates were analyzed by NMR, which provided strong evidence that CYP and DEL removal occurred mainly because of a biological process. The toxicity of the degradation products of strain HS-24 was studied simultaneously by measuring the light output of the luminescence bacterium. This demonstrated that the biodegradation ability of strain HS-24 significantly decreased the toxicity of CYP- and DEL-contaminated aquaculture seawater. Finally, the findings of this paper indicate that strain HS-24 is thus revealed as a biological agent for the remediation of marine aquatic environments.     

1959-2003年青海省干湿变化分析

利用青海省1959-2003年气象资料,计算了修正的Palmer干旱指数,并对其进行了分析。结果表明：在青海省旱涝监测中,PDSI指数反映旱涝程度更为客观;青海省的干旱主要以轻旱为主;夏秋季年际干湿交替较冬春季频繁,变化振幅也较大;秋季青海省干旱化倾向最为严重,冬春季出现轻旱几率最大。另外,春季干旱总面积在减小;夏季轻旱面积增加,而中旱、重旱面积在减小;秋冬季重旱面积在增加。     

Effect of atmospheric overlapping bands and their treatment on the calculation of thermal radiation

The effect of the overlapping band of atmospheric gases and its treatment on the calculation of flux and cooling rate due to the long wave radiation is investigated in detail by a new transmission model for overlapping bands, taking the 15 μm band of CO2 as an example. It is found that the presence of band overlapping has a quite significant influence on radiative fluxes and cooling rates in the upper stratosphere and the troposphere, in particular, at the earth's surface. However, in the middle-lower stratosphere, the overlapping effect appears to be insignificant. It is also shown that the usual wide-band transmission model treating the overlapping effect overestimates the net longwave fluxes in the lower stratosphere and, in particular, in the troposphere including the surface. But, in the middle-upper stratosphere, the contrary is the case.     

Constraints on sedimentary ages of the Chuanlinggou Formation in the Ming Tombs,Beijing, North China Craton: LA-ICP-MS and SHRIMP U–Pb dating of detrital zircons

Detrital zircons in five sedimentary samples, MC1 to MC5, from the bottom of the Chuanlinggou Formation in the Ming Tombs District, Beijing, were dated with the LA-ICP-MS and SHRIMP U–Pb methods. Age spectra of the five samples show a major peak at 2500 Ma and a secondary peak at 2000 Ma, suggesting their provenances were mainly from the crystalline basement of the North China Craton and the Trans-North China Orogen. The youngest zircon has an age of 1673 ± 44 Ma, indicating that the Chuanlinggou Formation was deposited after this age. From sample MC4 to MC5, lithology changed from a clastic rock (fine-grained sandstone) to a carbonate rock (fine-grained dolomite), suggesting that the depositional basin became progressively deeper. The age spectrum of sample MC5 shows a major peak at 2500 Ma and a secondary peak at 2000 Ma. Sample MC4, which is stratigraphically lower than sample MC5, only had one peak at 2500 Ma. We conclude that there was a transgressive event when sediments represented by MC5 was deposited, and seawater carried ca. 2000 Ma clastic materials to the basin where the Chuanlinggou Formation was deposited, leading to the addition of ca. 2000 Ma detritus. Our research indicates that the source area for the sediments became more extensive with time. We conclude that the Chuanlinggou Formation in the Ming Tombs District was deposited in a low-energy mud flat sedimentary environment in the inter-supra tidal zone because it is mainly composed of silty mudstone and fine-grained sandstone with relatively simple sedimentary structures.     

长江中下游特大桥主要工程地质问题的勘察与研究

20世纪90年代以来, 长江中下游特大跨江公路专用桥建设开始起步, 至今已有黄石、铜陵、江阴、武汉、南京等长江公路大桥建成通车, 并有多座大桥正在建设和勘测设计.在大桥建设中遇到了地震与断裂构造、软弱层带、极软岩、岩溶等复杂的工程地质问题.在解决这些问题中除了采用常规的工程地质勘察和试验技术外, 还进行了软岩流变试验、钻孔内彩色电视录像、原位承载力及压桩试验、桥基地质力学模型试验等技术和方法, 取得了可靠的数据, 为大桥设计提供了依据, 并通过已建成大桥的实践得到了证明.这些勘察研究的技术方法为长江中下游特大桥建设提供了经验.      

区域地球化学异常空间分形结构及其意义——以浙江省诸暨地区区域地球化学数据为例

区域地球化学数据既具有确定性的特征 ,又具有随机性的特征 ,从而地球化学异常的空间分布具有标度不变性的特征 ,即空间分形结构。本文运用元素含量 等值线面积模型、元素含量的周长与面积模型 ,查明区域地球化学异常分形结构 ,初步探讨了其形成机制 ,并讨论了元素含量与等值线面积的空间分形模型用于划分地球化学异常与背景的意义。     

几种环境因子对虾蟹类非特异性免疫的影响

综述了近10a国内外有关重金属、氨态氮、亚硝酸盐、有机污染物等几种环境因子对虾蟹类非特异性免疫影响的研究成果,以期为通过改善养殖环境条件提高虾蟹类自身免疫抗病力提供理论依据.同时,为进一步深入开展该领域的研究工作积累资料.     

重庆地震应急资料产出系统研发与应用

地震应急资料具有较强的时效性、专业性和多学科融合的特点。中强地震发生后启动应急响应,工作人员需在短时间内产出多学科、跨领域、多手段的专业地震会商资料。以地震会商系统为平台,利用其灵活开发、自动计算和智能分析的优势,建立地震应急资料产出系统（包括会商资料处理模块、应急图件产出模块和震情报告生成模块）,通过地震触发,根据预设流程和报告模板,自动产出专业报告,为震情形势研判和震后应急救援提供专业可靠的应急资料,最大限度地发挥应急救援和灾损评估的效能。