三七炮弹的碘化银成核率检测

三七炮弹是进行人工增雨和防雹作业所需碘化银催化剂的主要载体之一,炮弹中碘化银催化剂的成核率数据是人工影响天气作业设计和指挥中进行催化剂作业剂量测算的重要参考,因此,对人工影响天气业务中使用的三七炮弹的碘化银成核率进行检测非常重要。2013年11—12月中国气象局人工影响天气中心利用新建的1200 L等温云室和钢板式20 m3专用爆炸室等设备,对目前人工影响天气业务中使用的两个厂家三七炮弹 (样品1、样品2) 的碘化银成核率进行国内首次统一检测。检测结果表明:两厂家炮弹成核率检测结果的拟合值量级均为109~1012/(g·AgI)(检测温度-6℃至-20℃),样品2成核率明显高于样品1。将本次检测结果与国内历次三七炮弹检测结果相比发现,两样品在负温高温段的成核率值均高于以往检测结果,其中,在具有指示意义的-10℃下的成核率,两样品均比以往检测结果要高2~3个量级。不同检测实验中成核率检测结果存在较大差异的现状说明,采用同一平台开展成核率统一检测十分必要。     

Vertical fault systems in the tectonosphere geoelectrical section in petroliferous domains of Sakhalin Island (Russia) and Gulf of Tonkin (Vietnam): Evidence from magnetotelluric sounding

The transverse current anomalies evident from magnetotelluric sounding (MTS) data in the transition zone from the Asian continent to the Pacific Ocean and a geoelectrical model suitable for explaining these effects are discussed. Using simulation results and new MTS data on Sakhalin and northern Vietnam, ultra-deep fluid–fault system (UDFFS) models are constructed, comprising steeply dipping low-resistivity and high-resistivity linear bodies which penetrate through the whole section of the lithosphere, continuing deep into the asthenosphere. The structure of these systems reflects the development of deep and ultra-deep fault zones, along which mantle-originated fluids may migrate through sediments to reach the surface. This allows the anisotropic–conductive fractured structures adjacent to these faults to be considered as being most favorable for hydrocarbon accumulations.     

Simulation of mixed-mode fracture using SPH particles with an embedded fracture process zone

This paper focuses on the modelling of mixed-mode fracture using the conventional smoothed particle hydrodynamics (SPH) method and a mixed-mode cohesive fracture law embedded in the particles. The combination of conventional SPH and a mixed-mode cohesive model allows capturing fracture and separation under various loading conditions efficiently. The key advantage of this framework is its capability to represent complex fracture geometries by a set of cracked SPH particles, each of which can possess its own mixed-mode cohesive fracture with arbitrary orientations. Therefore, this can naturally capture complex fracture patterns without any predefined fracture topologies. Because a characteristic length scale related to the size of the fracture process zone is incorporated in the constitutive formulation, the proposed approach is independent from the spatial discretisation of the computational domain (or mesh independent). Furthermore, the anisotropic fracture responses of materials can be naturally captured thanks to the orientation of the fracture process zone embedded at the particle level. The performance of the proposed approach demonstrates its potentials in modelling mixed-mode fracture of rocks and similar quasi-brittle materials.     

Groundwater responses to the 2011 Tohoku Earthquake on Jeju Island,Korea

Groundwater responses at 15 monitoring wells on Jeju Island were observed in relation to the magnitude 9.0 Tohoku Earthquake off the Pacific coast of Honshu, Japan, on 11 March 2011, at 14:46:23 h local time (05:46:24 h UTC time). In coastal areas, the groundwater level responses to the earthquake were oscillatory at 12 wells, and the range of the maximum groundwater level changes was 3–192.4 cm. The response durations were approximately 1–62 min. The relationship between the maximum groundwater level changes and the response durations displayed a high correlation coefficient (r = 0.81). Groundwater temperature changes were also observed at 7 of 12 wells 3–10 min after the seismic wave arrived, and the range was from 0.01 °C to 1.20 °C. In mid‐elevation areas, the groundwater level changes appeared in three different forms: oscillatory, spiky and persistent. The groundwater temperature changes were also observed at two wells. One indicated decreasing and recovering temperatures, and the other exhibited rising and persistent temperatures. The primary temperature changes occurred 5–6 min after the earthquake and 2–3 min after the seismic wave arrived. In addition, the electrical conductivities at the depth of the transition zone were monitored, and the responses to the earthquake appeared at all three wells. Although the electrical conductivity and temperature changes were not well understood, groundwater inflow and mixing were likely caused by the earthquake, and the responses were various and site specific. The responses to the earthquake were closely related to the hydrogeological characteristics at each monitoring well, and a more detailed hydrogeological characterization is needed to understand the mechanisms related to earthquakes in general. Copyright © 2012 John Wiley & Sons, Ltd.     

Impact of seasonal variations in hydrological stresses and spatial variations in geologic conditions on a TCE plume at an industrial complex in Wonju,Korea

Spatial and temporal variations in a trichloroethylene (TCE) plume at an industrial complex in Wonju, Korea, were examined based on hydrogeological data and seven rounds of groundwater quality data collected over a year. The site has considerable vertical heterogeneities; the top layer of soil is covered by impermeable paving material at several locations, followed by a series of reclaimed or residual soil layers, and with weathered rocks to the crystalline biotite granite at the bottom. Areal heterogeneity in the surface conditions plays an important role in controlling groundwater recharge. The heterogeneity structure is influenced by complex surface conditions paved with asphalt and concrete. Owing to the presence of limited recharge area and concentrated summer precipitation events, the effects of seasonal variations on groundwater hydraulics tend to diminish with distance from the recharge area. This result was established by analysing the influence of the contrasting surface recharge conditions between the near‐source zone and the far zone, and the seasonally concentrated precipitation on the transport patterns of a TCE plume. In addition, variations in the plume's downstream contaminant flux levels were also analysed along a transect line near the source zone. The results show that the general tendency of the TCE plume contaminant concentration and mass discharges were reproducible if we account for seasonal recharge variations and the associated changes in the groundwater level. During recharge events, the TCE concentration variations appear to be influenced by leaching of the residual dense non‐aqueous‐phase liquid (DNAPL) TCE trapped in the unsaturated zone. This result shows that seasonal variations in contaminant plume near the source zone is inevitable at this site, and that these variations indicate the presence of residual DNAPL at or above the water table, at least in some isolated locations. Copyright © 2011 John Wiley & Sons, Ltd.     

Transnational labour migration and the politics of care in the Southeast Asian family

Recent increases in female labour migration in and from Asia have triggered a surge of interest in how the absence of the mother and wife for extended periods of time affects the left-behind family, particularly children, in labour-sending countries. While migration studies in the region have shown that the extended family, especially female relatives, is often called on for support in childcare during the mother’s absence it is not yet clear how childcare arrangements are made. Drawing on in-depth interviews with non-parent carers of left-behind children in Indonesia and Vietnam, the paper aims to unveil complexities and nuances around care in the context of transnational labour migration. In so doing it draws attention to the enduring influence of social norms on the organisation of family life when women are increasingly drawn into the global labour market. By contrasting a predominantly patrilineal East Asian family structure in Vietnam with what is often understood as a bilateral South-East Asian family structure in Indonesia, the paper seeks to provide interesting comparative insights into the adaptive strategies that the transnational family pursues in order to cope with the reproductive vacuum left behind by the migrant mother.     

Sources and Exchange of Particulate Organic Matter in an Estuarine Mangrove Ecosystem of Xuan Thuy National Park, Vietnam

The spatio-temporal variations in stable isotope signatures (??¹³C and ??¹⁵N) and C/N ratios of particulate organic matter (POM), and physicochemical parameters in a creek water column were examined in an estuarine mangrove ecosystem of Xuan Thuy National Park, Vietnam. The objective was to examine the factors influencing creek water properties, and the sources and exchange of POM in this important mangrove ecosystem. The diel and seasonal variations in water temperature, flow velocity, pH, dissolved oxygen, and salinity demonstrated that tidal level, season, and biological factors affected the creek water properties. Mangroves had relatively low ??¹⁵N and very low ??¹³C values, with respective average values of 1.5?±?0.9?? and ?28.1?±?1.4??. The low mangrove leaf ??¹⁵N indicated minor anthropogenic nitrogen loading to the mangrove forests. A significant positive correlation between POM?C??¹³C and salinity along the axis of Ba Lat Estuary, Red River, indicated that marine phytoplankton (??¹³C value, ?21.4?±?0.5??) was the predominant source of POM at the estuary mouth. Based on the co-variation of ??¹³C and C/N ratios, marine phytoplankton and mangrove detritus were predominant in POM of major creeks and small creeks, respectively. During the diurnal tidal cycle, the dynamics of POM were affected by sources of organic matter, tidal energy, and seasonal factors. The contribution of mangrove detritus to POM reached a maximum at the low tide and was enhanced during the rainy season, whereas marine phytoplankton contribution was highest at high tide.