DT-1型独头巷道高效通风系统的开发研究

介绍了一种独头巷道高效通风系统的组成、构造特点及其在坑道内的使用情况。     

Analysis of mine ventilation networks using nonlinear programming techniques

Summary Solving ventilation networks of natural air splitting is a classical problem in mine ventilation. A common approach to this problem is to formulate it based on Kirchhoff's voltage and current laws and obtain the solution by an iterative technique known as the Hardy Cross method. In this paper, it is shown that the problem can be formulated and analysed as an unconstrained optimization (minimization) problem. The computational experience with the method of conjugate gradients is also discussed.     

黄颡鱼（Pelteobagrus fulvidraco）鳃的超微结构研究

应用光学和电子显微成像技术对黄颡鱼鳃的表面形态特征、鳃小片血管分布及其内部超微结构进行了观察。结果表明,黄颡鱼鳃耙呈长锥形,鳃弓表面具棘状小刺,鳃小片呈褶皱状,镶嵌排列在长条形鳃丝两侧。光镜可观察到鳃小片两侧红色的入鳃和出鳃动脉以及中部片状毛细血管网。鳃耙、鳃弓、鳃丝及鳃小片表面均被扁平上皮细胞覆盖,其表面微嵴形态结构...     

海底隧道穿岛通风竖井地震作用下动力分析

通风竖井对隧道内的通风换气、车辆动力效应调整以及防灾救援起到至关重要的作用,是长大型隧道的重要组成部分。由于受到周围岩土的约束,海底隧道穿岛通风竖井结构的稳定性往往优于水中自立式竖井。但在地震动作用下,受周围岩土的约束及土体变形的影响,隧道通风竖井的地震响应将与普通井筒及井筒式基础存在明显差异。基于大型有限元分析软件ABAQUS建立海底隧道穿岛通风竖井结构的数值模型,考虑周围岩土及底部隧道对竖井的约束,利用时程分析法计算竖井在垂直于隧道轴向的水平地震作用下的动力响应,得出了竖井内力及位移沿深度的分布特点,通过考虑不同类型的岩土材料得到了竖井结构动力响应随场地剪切波速的变化规律。     

Response of drip water temperature to climate variability: a case study in Xiaoyan Cave,southwest China

Detailed monitoring of surface atmospheric and subterranean microclimatic conditions has provided a new opportunity to interpret drip water temperature changes associated with climate variability. High-resolution multi-index monitoring was conducted in Xiaoyan Cave, Guilin, southwest China, for a period of four years (2011–2014) to identify the processes that control drip water temperature. The results show that variations in drip water temperature are mainly coupled to changes in the cave air temperature unless large drip discharge occurs. The controls on cave air temperature depend on the ventilation modes that eventually affect drip water. The multiple thermal mechanisms are winter ventilation, heat conduction in summer and water flow-induced convection derived from subsurface water percolation into the cave due to fast preferential flow during heavy rain events. Drip water response to extreme temperature anomalies is shown to be sensitive to outside climate.     

基于风廓线雷达的北京春季一次“先霾后沙”空气污染过程分析

利用NCEP再分析资料、逐小时污染物浓度数据、风廓线雷达及地面常规观测资料,对北京2018年3月26—29日一次“先霾后沙”的空气污染过程进行了分析。结果表明：霾污染期间PM_2.5峰值浓度为242 μg·m^-3,PM_2.5/PM₁₀值为0.86。受蒙古气旋影响,PM₁₀浓度出现爆发性增长,增长速率达到912 μg·m^-3·h^-1,PM_2.5/PM₁₀值下降至0.11。霾主要影响时段边界层内以西南风为主,平均通风量为15 907 m²·s^-1,大气边界层以稳定的弱上升或下沉运动为主;而沙尘影响时段平均通风量为9 226 m²·s^-1,沙尘天气爆发前边界层明显的下沉运动先于地面污染物浓度的变化。基于后向轨迹模式和潜在源贡献分析方法PSCF计算结果,霾影响时段河北中南部、山西中部等地对北京PM_2.5贡献较多;而沙尘影响时段,北京地区的PM₁₀主要来源于内蒙古中部和辽宁西部。     

Analysis of an Ensemble of High-Resolution WRF Simulations for the Rapid Intensification of Super Typhoon Rammasun(2014)

Diagnostics are presented from an ensemble of high-resolution forecasts that differed markedly in their predictions of the rapid intensification(RI) of Typhoon Rammasun. We show that the basic difference stems from subtle differences in initializations of(a) 500-850-h Pa environmental winds, and(b) midlevel moisture and ventilation. We then describe how these differences impact on the evolving convective organization, storm structure, and the timing of RI. As expected,ascent, diabatic heating an...     

Ventilation of the North Pacific Ocean: Water exchange between subtropical and tropical gyres

INTRODUCTIONIntheearly 1 980 s,ventilationtheoryemergedtopredictthehorizontalandverticalstructureofthethermocline.Thereweretwodifferentviewsonthestratifiedoceans.Thefirsttheory (RhinesandYoung,1 982 ,hereafterRY ;YoungandRhines,1 982 )proposedanunventilatedmodelinwhichonlytheuppermostlayerisexposedtothesurfaceandisforcedbythewindstress.Thesecondtheory (Luytenetal.,1 983 ,hereafterLPS)offeredaventilatedmodelwhichisclosertotheclassicalthermoclinetheoriesthanthatofthefirstone (e.g .,Nee…     

Temporal and spatial variations of radiocarbon in Japan Sea bottom water

In 1995 and 2000, the radiocarbon ratio (Δ¹⁴C) of total dissolved inorganic carbon was measured in the Japan Sea where deep and bottom waters are formed within the sea itself. We found that (1) since 1979, the Δ¹⁴C in bottom water below about 2000-m depth in the western Japan Basin (WJB) had increased by about 30‰ by 1995, and (2) the bottom Δ¹⁴C in the WJB did not change between 1995 and 2000. The former finding was due to penetration of surface bomb-produced radiocarbon into the bottom water owing to bottom ventilation, whereas the latter was caused by stagnation of the bottom ventilation there. In the eastern Japan Basin (EJB), the bottom Δ¹⁴C also increased by about 30‰ between 1979 and 2002. Recent stagnation of the bottom ventilation in the EJB is also suggested from analyses of constant bomb-produced tritium between 1984 and 1999. The temporal variations of Δ¹⁴C, tritium, and dissolved oxygen in the bottom waters indicate that: (1) new bottom water is formed south of Vladivostok in the WJB only in severe winters; and (2) the new bottom water then follows the path of a cyclonic abyssal circulation of the Japan Sea, which results in the increases in dissolved oxygen and the transient tracers in the bottom waters in the EJB and Yamato Basin with an approximate 3-to 6-year time lag. This process is consistent with the spatial variations of Δ¹⁴C, bomb-produced ¹³⁷Cs, and chlorofluorocarbon-11 in the bottom waters of the Japan Sea.     

基于探空数据的新疆大气扩散条件时空分布特征分析

利用2010—2019年新疆14个探空气象站资料统计分析了近10 a大气最大混合层高度(下文简称混合层高度)、通风量、边界层平均风速及大气自净能力指数的时空分布特征,探讨了各物理参数与空气质量的关系.结果表明:(1)以上参数的逐月分布均呈倒"V"型,表现为夏半年大、冬半年小,即新疆的大气扩散能力在夏季最强、冬季最弱,其...