Water discharge variability of Changjiang(Yangtze) and Huanghe(Yellow) Rivers and its response to climatic changes

Influences of large-scale climatic phenomena, such as the E1Nifio/La Nifia-Southem Oscillation （ENSO） and the Pacific Decadal Oscillation （PDO）, on the temporal variations of the annual water discharge at the Lijin station in the Huanghe （Yellow） River and at the Datong station in the Changjiang （Yangtze） River were examined. Using the empirical mode decomposition-maximum entropy spectral analysis （EMD- MESA） method, the 2- to 3-year, 8- to 14-year, and 23-year cyclical variations of the annual water discharge at the two stations were discovered. Based on the analysis results, the hydrological time series on the inter- annual to interdecadal scales were constructed. The results indicate that from 1950 to 2011, a significant downward trend occurred in the natural annual water discharge in Huanghe River. However, the changes in water discharge in Changjiang River basin exhibited a slightly upward trend. It indicated that the changes in the river discharge in the Huanghe basin were driven primarily by precipitation. Other factors, such as the precipitation over the Changjiang River tributaries, ice melt and evaporation contributed much more to the increase in the Changjiang River basin. Especially, the impacts of the inter-annual and inter-decadal climate oscillations such as ENSO and PDO could change the long-term patterns of precipitation over the basins of the two major rivers. Generally, low amounts of basin-wide precipitation on interannual to interdecadal scales over the two rivers corresponded to most of the warm ENSO events and the warm phases of the PDO, and vice versa. The positive phases of the PDO and ENSO could lead to reduced precipitation and consequently affect the long-term scale water discharges at the two rivers.

Impeded Acidification of Acid Sulfate Soils in an Intensively Drained Sugarcane Land

Recent research results suggest that acidification of acid sulfate soils may be inhibited in well-drained estuarine floodplains in eastern Australia by the absence of natural creek levees. The lack of natural levees has allowed the inundation of the land by regular tidal flooding prior to the construction of flood mitigation work. Such physiographical conditions prevent the development of pre-drainage pyrite-derived soil acidifica- non that possibly occurred at many levee-protected sites in eastern Australian estuarine floodplains during extremely dry spells. Pre-drainage acidification is considered as an important condition for accumulation of soluble Fe and consequently, the creation of favourable environments for catalysed pyrite oxidation. Under current intensively drained conditions, the acid materials produced by ongoing pyrite oxidation can be rapidly removed from soil pore water by lateral leaching and acid buffering, resulting in low concentrations of soluble Fe in the Pyretic layer, which could reduce the rate of pyrite oxidation.

Response of the distributary channel of the Huanghe River estuary to water and sediment discharge regulation in 2007

The water and sediment discharge regulation （WSDR） project, which has been performed since 2002 before flood season every year, is of great significance to the river management in China. Until 2007, six experiments have been fulfilled to evaluate the effect of the project on the natural environment. To fill the gap of investigations, a study on flood and suspended sediment transportation and channel changing along the distributary channel of the Huanghe （Yellow） River was conducted during the WSDR project period in 2007. The lower channel was scoured rapidly and the channel became unobstructed gradually several days after the flood peak water was discharged from the Xiaolangdi Reservoir. Within four days after the flood peak at 3 000 m3/s entered the distributary, the channel in the river mouth area was eroded quickly. Both the mean values of area and depth of the main channel were tripled, and the maximum flood carrying capacity increased to 5 500 m3/s or more. Then, the river channel was silted anew in a very short time after completion of the WSDR. Favored by the WSDR project, the fiver status in April 2008 became better than that of the year before. The adjustment ranges of main channel parameters were about 30%, 10%, and 10% at sections C2, Q4, and Q7, respectively. The process of rapid erosion-deposition was more active 15 km away in the channel from the fiver mouth due to the marine influence. It is reasonable for discharging sediment at concentration peak from Xiaolangdi Reservoir at the end of the flood peak. As a result, the sediment peak reached the river mouth about two days later than that of the water current. In addition, the WSDR project has improved the development of the estuarine wetland. Wetland vegetation planted along the river banks restrained the water flow as a strainer and improved the main channel stability. It is suggested to draw water at mean rate of 150 m3/s from the Huanghe River during flood periods, because at the rate the water in the wetland would be stored and replenished in balance. Moreover, we believe that cropland on the river shoal of the lower Huanghe River should be replaced by wetland. These activities should achieve the Huanghe River management strategy of ＂To concentrate flow to scour sediment, stabilize the main channel, and regulate water and sediment＂.

Iron Phosphate Coating: A Novel Approach to Controlling Pyrite Oxidation

A novel coating technique was developed for controlling Pyrite oxidation. The technique invo1ved leachingpyrite particles with a solution containing low concentrations of phosphate and hydrogen peroxide. Duringthe leaching process, the iron released from pyrite by hydrogen proxide was precipitated by phosphate as aferric phosphate coating. This coating was shown to be able to effectively prevent Pyrite from oxidation and itcould be established at the expense of only surface portions of Pyrite. The emergence of this technique couldprovide a unique potential route for abating acid mine drainage and reclaiming sulfide-containing degradedmining land.

基于火下阴承、异病同治探讨张仲景鸡子黄类方在2型糖尿病中的应用

2型糖尿病可归属于中医“消渴病”范畴。“火下阴承”源于《黄帝内经》中“君火之下,阴精承之”,而消渴病核心病机及治法与之相契合。张仲景鸡子黄类三方为百合鸡子汤、黄连阿胶汤、排脓散,分散在《伤寒杂病论》不同篇章之中。剖析总结此三方的机理特点,认为符合“火下阴承”的治法特点,契合2型糖尿病之消渴病机。此三方均由鸡子黄不同配伍组成,百合鸡子汤为鸡子黄配伍百合,可治疗2型糖尿病及其合并精神相关疾病;黄连阿胶汤为鸡子黄配伍阿胶、芍药、黄连、黄芩,可治疗2型糖尿病及其合并心肾系统疾病;排脓散为鸡子黄配伍芍药、桔梗、枳实,可用于治疗2型糖尿病并发痈疽。因此,基于“火下阴承”的相关现代研究提出鸡子黄三方在2型糖尿病中的应用,可为临床治疗提供思路。

排毒保肾丸对肾纤维化大鼠肾组织TGF-β1/Smad信号通路的影响

目的观察排毒保肾丸对5/6肾切除大鼠肾纤维化的影响并探讨其可能作用机制。方法将50只SD大鼠随机分为正常组、假手术组、模型组、排毒保肾丸组、尿毒清颗粒组,每组10只。除正常组、假手术组外,其余各组大鼠均采用5/6肾切除方法建立肾纤维化模型。排毒保肾丸组和尿毒清颗粒组分别予排毒保肾丸1.0 g/(kg·d)和尿毒清颗粒3.33 g/(kg·d)灌胃,正常组、假手术组、模型组予2 ml生理盐水灌胃,每日1次。各组均灌胃4周后处死大鼠,取残肾组织行HE、PAS、PASM、Masson染色病理观察,检测肾组织转化生长因子β1(TGF-β1)、Smad2、Smad7蛋白及其mRNA的表达水平。结果病理结果显示,模型组大鼠局灶节段性肾小球缺血性皱缩,较多炎性细胞浸润伴轻至中度纤维化;与模型组比较,排毒保肾丸组残肾组织病变程度减轻。与正常组、假手术组比较,模型组大鼠TGF-β1蛋白及其mRNA、Smad2蛋白及其mRNA表达水平均显著升高,Smad7蛋白及其mRNA表达水平均显著下降(P<0.01);与模型组比较,排毒保肾丸组和尿毒清颗粒组TGF-β1蛋白及其mRNA、Smad2蛋白及其mRNA表达水平均显著降低,而Smad7蛋白及其mRNA表达水平均显著升高(P<0.01)。结论排毒保肾丸有抗肾纤维化的作用,下调肾组织TGF-β1、Smad2的表达和上调Smad7的表达可能是其作用机制之一。

Removing coarse sediment by sorting of reservoirs

Reservoir sedimentation is an unsolved problem.In this paper,based on measured data,theoretical analysis and numerical computations,we prove that a proportion of the sediment coarser than 0.1 mm(CS) is sorted and deposited in specific reaches in the upper backwaters or in run-of-river reservoirs.The ratio of CS is usually small but it impacts the slope of deposition delta greatly and raises the backwater in later stages for a river shaped reservoir(RSR).Based on these facts,we propose to remove such CS from a fixed basin(FB) in the upper backwater by dredging and we prove that the removal of CS is effective in reducing sediment deposition and in preserving the long-term capacity of reservoirs.A numerical model computation of the Three Gorges Project(TGP) reservoir indicates that dredging 30×106-50×106 t/a of CS could reduce 20% total deposition by the end of 100th year,so that the slope of deposition can be slowed down by 25%-30%.This would be remarkable for a long extended RSR.This method of removing CS can also be applied to the Xiaolangdi reservoir(XLD) on the Yellow River(YR) to not only limit reservoir deposition but also filter out the CS from entering the Lower Yellow River(LYR) to slow down the rise of the perched LYR.It provides a new alternative to postpone the continuous siltation of the LYR.

我演“小角色”

本刊从本期起,“校友来信”一栏改为“校友园地”栏。在这个专栏里,将发表校友在编剧、表导演、舞台美术等艺术实践中的经验和心得体会,以及对当前戏剧理论、创作、演出、艺术教育等方面的某些看法。文字力求观点鲜明、论据充分、短小精悍、生动活泼。希望广大校友都来耕耘这块园地,使它开出万紫千红、笔奇丰艳的花朵,结出丰腴硕大的果实。