The interference of a semi-submerged obstacle on the porous breakwater

The interaction of a linear water wave in a channel of constant depth impinging on a vertical thin porous breakwater with a semi-submerged and fixed rectangular obstacle in front of it is investigated. The water follows conventional assumptions as an irrotational, incompressible, and inviscid fluid flow. The solid skeleton of the porous breakwater is assumed to be rigid and thin. We get the general solution by applying the eigenfunction expansion method and solve it with a numerical matrix solver. In order to verify the correctness of the general solution, wave flume experiments are conducted. Two asymptotic solutions for long and short incoming waves are also obtained. Both experiments and asymptotic solutions show good agreement with the general solution at proper limits. Finally, the effect of the fixed obstacle on the porous breakwater is discussed, and a general guide of how to obtain better energy trapping is delivered.     

某些环境因子对鲫鱼(Carassius auratus)和鲮鱼(Cirrhinus molitorella)呼吸作用的影响

通过压力一电换能器记录了温度、酸碱度和Cu2+对鲫鱼或鲮鱼呼吸作用的影响。温度变化主要影响鱼的鳃盖运动，而酸碱度和Cu2+主要对鱼的咳嗽运动产生影响，这是因为咳嗽运动的作用是洗去积存于鳃上的污物。     

Nitrogen and Phosphorus Diffusive Fluxes Across the Sediment-Water Interface in Estuarine and Coastal Tidal Flats

Nitrogen and phosphorus contents are analyzed in the overlying waters and pore waters taken from the Changjiang Estuary and Shanghai coastal tidal flats in this study. In addition, the diffusion fluxes of nitrogen and phosphorus across the sediment-water interface in tidal flats are estimated according to the nutrient concentration gradients at the interface. It has been indicated that the concentrations of ammonium, nitrite, nitrate and dissolved phosphorus in overlying waters range from 0.0082～2.56, 0.03～0.58, 0.69～5.38 and 0.035～0.53 mg/L, respectively, while 0.0025 ～ 1.35 mg/L for NH4+-N, 0. 0055 ～ 0.20mg/L for NO2--N, 0.61～1.14 mg/L for NO3--N and 0.11～0.53mg/L for DP insurface pore waters.The findings have revealed that ammonium, nitrite, nitrate and dissolved phosphorus diffusion fluxes across the sediment-water interface are between -0.024～0.99, -0.39～ -0.0019, -3.09～the source of phosphorus and an important sink for nitrogen in the waters.     

海水中铁的几种形态对海生小球藻生长的影响

通过实验室一次性培养 ,研究不同形态的铁 :Fe3 + ,Fe2 + ,Fe3 + - EDTA,Fe2 + - EDTA以及胶体水合氧化铁在不同条件下对海生小球藻 (Chlorella vulgaris)生长的影响。实验结果表明 ,铁对小球藻生长影响的主要生物活性形式是有机络合态铁和胶体水合氧化铁 ,光诱导还原态 Fe2 + 也很重要。它们都积极促进了藻类的生长繁殖 ,其中 EDTA与铁离子结合的动力学过程并不明显影响藻类吸收铁。小球藻相对生长率的提高和叶绿素 A(Chl.a)的增加取决于铁的总量及其转变为可利用状态的速率 *和藻类的有效吸收。在不同的培养体系中 ,常量营养盐 N、P与 Fe的缺乏对藻类生长起着交互限制作用 ,其中缺 P比缺 N更能减少 EDTA络合铁对小球藻生长繁殖的促进作用。     

可可西里古近系石盐测井评价方法研究

可可西里雅西措组发育多层石盐层。为有效识别石盐矿深度、厚度,预测其工业品位,提出基于归一化后的自然伽马和密度曲线重构石盐指示曲线,用以划分石盐与砂泥岩,该方法与测井交会图法、测井曲线重叠法相比精度高。利用石盐指示曲线与石盐样品测试结果建立预测石盐矿工业品位相关关系,与自然伽马法、孔隙度曲线法计算的结果相比,误差小,应用效果良好。因此,测井方法在石盐勘探评价中具有广泛的运用前景。     

Formation Pressure Estimation Method for High Temperature and High Pressure Wells in Ledong Area of South China Sea

Natural Resources Research - The Ledong area is a typical high temperature and high pressure area in the South China Sea's Yinggehai Basin. The geological structure of this basin is complex,...     

Numerical simulation for different motion forms of sliding soil along slope with PFC3D

The motion forms (deformation) of the sliding soil along the slope include inviscid particle flow, viscous particle flow, and mass sliding. The motion forms were mainly influenced by the mechanical properties of the viscous mud medium filling. The effect of the medium filling on the motion forms of the sliding soil is worth discussing. The sliding soil can be seen as the mixture which is composed of the medium filling and coarse particles. The Chengdu clay with different moisture contents were selected as the medium filling. Their mechanical parameters were experimentally measured for simulating the moving process of the sliding soil. Different motion forms of the sliding soil were numerical simulated based on PFC3D by changing the specific mechanical parameters. The mechanical parameters of the Chengdu clay are experimentally determined. The numerical results show that with the moisture content of the filling slurry medium in the range of >302%, 101%~182%, and <80%, the motion form of the sliding soil belongs to the inviscid particles flow (similar with the sliding sand), viscous particles flow (seen as the viscous flows); and mass sliding (seen as the block sliding along the slope surface), respectively.     

持续性逆温天气对哈尔滨市空气质量的影响

利用2013—2016年哈尔滨市07:00和19:00探空逆温资料及哈尔滨市环境监测站空气污染物浓度监测资料,对哈尔滨市低空温度层结特征及其与主要空气污染物(SO_2、NO_2、PM_(10)和PM_(2.5))浓度之间的关系进行了统计分析。结果表明:(1)哈尔滨市2013—2016年07:00持续性逆温天气出现频率是61.5%,19:00为58.8%。(2) 07:00和19:00逆温厚度月变化趋势基本一致,季节变化趋势也一致:冬季秋季春季夏季。(3)哈尔滨市冬半年逆温层出现频率明显高于夏半年,秋、冬季产生的逆温强度强于春、夏季。(4) 4年来哈尔滨市空气污染物浓度与持续性逆温频率、厚度呈正相关;与07:00逆温强度呈正相关,与19:00逆温强度的相关性不明显,说明哈尔滨市低空大气逆温层结状况是影响哈尔滨市空气质量的主要因素之一。(5)高纬冷平流弱,低层增暖,同时海平面气压场弱,大气水平和垂直方向输送能力差,从而使得污染物难以扩散进而堆积,这是持续数日重度污染的重要原因。     

珠江三角洲径潮相互作用下潮能的传播和衰减

因径流潮汐相互作用,三角洲各水道的能通量包含径流引起的净通量及潮汐引起的潮能通量。本文利用珠江三角洲多断面实测水位及流量的同步测量数据,建立基于径潮耦合的调和分析模型,剥离径流信号,计算出各站的总潮能及M₂、K₁及高频浅水分潮的潮能,对珠江三角洲潮能的沿程传播及衰减进行研究。结果表明,通过虎门进入珠江三角洲的潮波能量约占51.2%,而通过崖门、蕉门、磨刀门传入三角洲的潮能约占37%;同时,因地形摩擦、径流耗能效应,三角洲各水道的总能量损耗为148.33 MW。潮波能量按汇聚型和分散型两大类型沿三角洲不同位置传播并沿程衰减。虎门狮子洋及珠江正干、崖门至潭江石咀两大水道体系,其潮能沿程分散传入不同汊道,断面总潮能的衰减幅度大于单宽潮能通量的衰减,单宽潮动能沿程平均衰减速率大于潮势能,半日分潮的潮能衰减速率大于全日分潮。虎门狮子洋因其形态影响,M₂分潮振幅（或势能）的衰减最小,虎门至泗盛围段增加,平均每千米约增加0.77%。西四口门潮能汇聚于西海水道天河断面,总潮能的衰减速率小于磨刀门水道单宽潮能衰减速率。沿横门、洪奇门、蕉门进入的潮波多次交汇、分散,自横门至小榄、南华,南沙至海尾、荣奇,其单宽潮动能及M₂、K₁分潮动能的衰减速率小于潮势能,高频分潮势能沿程增加。     

辉长岩韵律层厚度的分形结构与模拟计算——以攀枝花层状侵入体为例

运用分形理论对四川攀枝花层状侵入体的韵律层厚度进行分维计算, 并结合计算机模拟手段, 对韵律层理的成因进行了探讨.通过分形计算表明, 攀枝花层状侵入体的韵律层在厚度上具有分形结构, 其分维数介于1.4~1.8之间, 不同级别韵律层的厚度分维数不同, 韵律演化的级别越高, 厚度分维数越大.通过模拟计算的韵律色度分维数与实测韵律层的厚度分维数比较接近, 变化规律也比较相似, 这不仅说明在韵律的演化过程中, 厚度和色率之间有一定的内在联系, 也说明了重力在韵律形成机制中是一个重要的影响因素.地球的重力作用与地球的其他物理化学作用在空间和时间上耦合, 形成了这种具有时空分形结构的韵律现象.