Spatial evolution equation of wind wave growth

Early in the thirties of the last century, the former Soviet scientists proposed characteristic waves (such as significant wave, and mean wave) to manifest the behavior of wind waves and began to study growth of wind waves. Later on Sverdrup and Munk[1] u…     

Life history, habitat utilisation, and biomass of introduced Mysis relicta

Life history, habitat utilisation, and biomass of benthic and pelagic opossum shrimp (Mysis relicta) were studied in the oligotrophic Lake Jonsvatn, central Norway. Sampling in the pelagic zone was done by means of a closing zooplankton net; in the benthic zone by means of a benthic beam trawl.

M. relicta had a mixed one or two year life cycle. In the autumn, the proportion of mature females and males were larger in the pelagic than in the benthic habitat. Copulation took place in late autumn, and the first females with eggs occurred in November. In February, the first juvenile M. relicta were released in the benthic habitat. In May and July, however, juveniles were found in large numbers in all parts of the lake. The length distribution of M. relicta indicates that juveniles partly segregate between benthic and pelagic habitats.

Both juvenile and adult M. relicta performed vertical diel migrations in the pelagic habitat. In the benthic habitat, diel vertical migrations along the bottom were not as pronounced as vertical migrations in the pelagic habitat. In the benthic habitat, major migrations were performed only by adults in the autumn. Our results indicate that the light intensity in the green part of the spectrum gives the proximate cue for regulation of vertical distribution of M. relicta.

The mean total biomass varied between 288 and 1576 kg dry weight, corresponding to 23.2–127.1 mg dry weight m⁻² surface area. M. relicta had smallest biomass during late spring/early summer and largest biomass during autumn and early winter. Estimated pelagic biomasses were largest in February, August, October and November, while benthic biomasses were largest in May and July. Estimated biomass of pelagic M. relicta during autumn was approximately 1/10 of the estimated biomass of zooplankton in this lake.     

三维介质界面裂纹的动力分析

本文通过区域的连续映射推导了一种映射半解析边界元法，将其应用于界面裂纹问题的动力分析，可大大减小计算一。典型算例的结构表明，本文方法是非常有效的，并可推广应用于三维复杂形状裂纹的计算问题。     

An X-ray excited optical luminescence study of a zoned quartz crystal from an emerald-bearing quartz vein,Hiddenite, North Carolina,USA

The optical luminescence excited with synchrotron radiation along a preferential orientation of a quartz crystal has been investigated. It is found that the crystal is composed of two distinct regions, only one of which luminesces upon X-ray excitation. This luminescence is generally uniform and exhibits emission bands in the blue (470 nm with a shoulder at 522 nm) and in the UV (340 nm) regions of the spectrum. The branching ratio for the intensity of these bands is sensitive to the excitation energy across the Si K-edge. XANES spectra collected by partial luminescence yield (PLY) suggest that both emission bands originate from the de-excitation of Si atoms in the quartz. The possible defect sites within the crystal structure that could account for the observed luminescence are investigated and discussed. Additional experiments are proposed to verify this assignment of the optical emission bands.     

Crustal Growth Rate of the North China Platform：a Method of Estimating Mass Equilibrium between Crust and Mantle

The following equation is proposed in this paper to estimate the crustal growth rate of the North China Platform on the basis of mass equilibrium between the crust and the mantle:

In-situ Growth of Calcite at Devils Hole, Nevada: Comparison of Field and Laboratory Rates to a 500,000 Year Record of Near-Equilibrium Calcite Growth

Calcite grew continuously for 500,000 years on the submerged walls of an open fault plane (Devils Hole) in southern Nevada, U.S.A. at rates of 0.3 to 1.3 mm/ka, but ceased growing approximately 60,000 years ago, even though the fault plane remained open and was continuously submerged. The maximum initial in-situ growth rate on pre-weighed crystals of Iceland spar placed in Devils Hole (calcite saturation index, SI, is 0.16 to 0.21 at 33.7 °C) for growth periods of 0.75 to 4.5 years was 0.22 mm/ka. Calcite growth on seed crystals slowed or ceased following initial contact with Devils Hole groundwater. Growth rates measured in synthetic Ca-HCO₃ solutions at 34 °C, CO₂ partial pressures of 0.101, 0.0156 (similar to Devils Hole groundwater) and 0.00102 atm, and SI values of 0.2 to 1.9 were nearly independent of P_{CO 2}, decreased with decreasing saturation state, and extrapolated through the historical Devils Hole rate. The results show that calcite growth rate is highly sensitive to saturation state near equilibrium. A calcite crystal retrieved from Devils Hole, and used without further treatment of its surface, grew in synthetic Devils Hole groundwater when the saturation index was raised nearly 10-fold that of Devils Hole water, but the rate was only 1/4 that of fresh laboratory crystals that had not contacted Devils Hole water. Apparently, inhibiting processes that halted calcite growth in Devils Hole 60,000 years ago continue today.     

大理岩破坏阶段Biot系数研究

在流固耦合研究中经常采用有效应力原理,Biot系数的确定为其中困难之一。为了研究含裂纹大理岩中Biot系数演化规律,在三轴压缩塑性变形后期阶段的不同轴向变形条件下,进行轴向压力加卸载循环;并在轴向压力卸载末期对岩样施加孔隙水压力。通过记录试样的变形,在Shao提出的Biot系数计算方法的基础上,计算轴向和侧向Biot系数。得到了不同围压条件下轴向和侧向Biot系数随轴向变形的演化规律,并对此进行了深入分析。结果表明：（1）Biot系数表现为各向异性,三轴压缩试验时,试样中大部分裂纹沿最大正应力方向扩展,是造成这种现象的直接原因;（2）轴向和侧向Biot系数随着轴向变形的增大而增大,轴向变形的增大引起岩样中裂纹扩展,导致Biot系数增大;（3）低围压条件下轴向和侧向Biot系数均比高围压条件下的值大,这是由于破坏方式不同引起的。     

Diary of forthcoming events

Abstract

Freshwater and sediment are crucial to the development and health of aquatic and wetland ecosystems in deltaic coastal regions. This study examines the long-term freshwater inflow (1940–2002) and total suspended solid loading (1978–2001), and their relationships with climate variables in three major river watersheds to Lake Pontchartrain, the largest inland estuary in the USA. The results show an average total annual freshwater inflow of 5.04 km³ and an average total annual sediment loading of 210 360 t, with the highest contributions from the Amite River watershed. Over 69% of annual inflow occurred within the six months from December to May. About 66–71% of the annual total suspended solid loading occurred within the four months from January to April. An increasing trend of annual water inflow and sediment discharge was found in the Amite River watershed over the past 60 years, coinciding with the fastest population growth in this upper Lake Pontchartrain basin.     

The Ecological Restoration of Heavily Degraded Saline Wetland in the Yellow River Delta

As a result of discontinuous water flow, agriculture, and increasing urban use of fresh water affecting the natural wetlands of the Yellow River Delta, these areas have experienced significant degradation in the past two decades, ultimately diminishing the overall natural wetland land area in the region. This study aimed to address the issue of decreasing fresh water in the Yellow River Delta by studying the effects of three different approaches to restoration on long‐term wetland recovery. The results of the study demonstrated that soil salt and available Na contents significantly decreased in response to all three restoration treatments. Impacts of the restoration treatments were more significant in 2009 than in 2010, as shown by the high rate of activity in the reed debris group. The highest phosphatase activity of the experimental period was also observed in the reed debris group. Meanwhile, a marked variation in soil nutrient elements (total carbon (TC), total nitrogen (TN), available phosphorus, and available potassium) was observed in the restoration treatment plots throughout the experimental period. TC and TN contents were generally higher in the restoration treatment groups than in the control group. Moreover, urease and phosphatase activity levels were highly correlated with one another, as well as with soil nutrient elements. In 2009, the yield of the Suaeda salsa plant was highest in the reed debris treatment group and lowest in the ploughing treatment group. The S. salsa plant did show a positive response to all of the different restoration treatments. Taken together, these results suggest that restoration approaches that implement ploughing techniques aided in the restoration of degraded saline wetlands.     

新丰江水库大坝贯穿裂缝及其稳定性分析

1962年3月19日新丰江水库大坝附近发生M_S 6.1级强烈地震后,13-17#坝段在108.5m高程处出现了长达82m的贯穿裂缝,导致水库渗漏,其后虽进行了加固处理,但经过50多年的运营,贯穿裂缝的现状如何,备受各级政府及专家学者的关注。本文利用近些年大坝上的多次小震观测记录,通过对有无贯穿裂缝坝段的地震加速度时程傅氏谱及上下坝体传递函数的对比分析,对14#坝段的整体性和稳定性进行了系统研究。结果表明,到目前为止,大坝贯穿裂缝没有明显恶化,但整体性依然较差,仍然是大坝稳定性的最大隐患。