宽水网地区三角高程测量代替等级水准测量的可行性

对虎门大桥等4座特大桥三角高程网试验观测数据进行了统计分析,比较了往返测高差较差、环闭合差与三、四等水准相应限差的差异及公共点上三角高程值与二等跨河水准高程值的差异,证实在宽水网地区用对向三角高程代替四等水准进行跨河水准测量是完全可行的,但代替三等跨河水准测量,可靠性只有75%左右。

台站短水准测量图件辅助管理系统简介

利用Access97编制了《台站短水准测量图件辅助管理系统》程序。本文简要介绍了该程序的设计思路。

长江三峡工程垂直位移监测网(全网)测量

长江三峡工程垂直位移监测网,是为三峡水利枢纽工程垂直位移监测提供基准点,以及了解坝址附近地壳形变而设立的专用网,有普通水准标石、测温钢管标、双金属标共40座,水准路线长约80km,跨河水准3处.主要介绍垂直位移监测网施测全过程、网型、标点结构、外业施测方法、内业数据处理、平差计算等.

稳定的频率域提取接收函数方法研究

频率域提取接收函数时引入"水准量"来代替垂向分量频谱中比较小的成分以保证反褶积结果的稳定性,却降低了精度,尤其对反映深部壳幔结构的低频信息影响较大;实际的等效震源时间函数长度是有限的,由于地震记录上后续干扰震相能量的影响,垂直分量波形往往比较复杂,若将其直接作为等效震源时间函数必然影响所提取接收函数的精度.针对以上问题,本文改进"水准量"的使用方法,并采取折中方案选取"水准量"和等效震源时间函数的长度,以便在频率域反褶积中得到稳定的接收函数,同时提高反褶积的精度.对观测数据的试验效果显示,本文方法提取的接收函数稳定性好、精度高。

Research on Precise Trigonometric Leveling in Place of First Order Leveling

Through the analysis of the principle, error sources and precision of trigonometric leveling, this paper points out the key problems about first order leveling replaced by trigonometric leveling; and for the first time puts forward that, in some given conditions, it is not only feasible but also valuable to replace first order leveling by precise trigonometric leveling, and proves it by experimentation as well. The content and conclusion of this paper have consulting significance and practicable value for our setting down relational criterion and production practice.

Distribution of nutrients and eutrophication assessment in the Bohai Sea of China

Water samples were collected in 120 stations in the Bohai Sea of China to analyze the distribution of dissolved nutrients and assess the degree of eutrophication in August 2002. The result shows that the average concentration of DIN increased and the PO4-P concentration sharply decreased compared to the previous data of corresponding period. The high concentrations of DIN and PO4-P occurred in coastal waters, especially in the bays and some river estuaries, while the high concentrations of SiO3-Si in the surface and middle depth occurred in the central area of the Bohai Sea. The average ratio of DIN/PO4-P was much higher than the Redfield Ratio （16：1）. Apparently, PO4-P was one of the limiting nutrient for phytoplankton growing in the sea. The average concentrations of DON and DOP were higher than their inorganic forms. The results of eutrophication assessment show that 22.1% of all stations were classified as violating the concentration levels of the National Seawater Quality Standard （GB 3097-1997） for DIN and only 3.9% for PO4-R The average eutrophication index in the overall area was 0.21±0.22 and the high values occurred in Bohai Bay, Liaodong Bay and near the Yellow River estuary. This means that the state of eutrophication was generally mesotrophic in the Bohai Sea, but relatively worse in the bays, especially some river estuaries.

Gradient principle of horizontal stress inducing rock burst in coal mine

Based on the stress distribution characteristics of rock burst multiple sites, the criterion of horizontal stress inducing layer dislocation rock burst was established. Accordingly, the influencing factors were analyzed. The analysis results indicate that the stress condition, edge of etastic zone depth, supporting strength, and the friction angle and cohesion among coal stratum, roof and floor are sensitive factors. By introducing double-couple model, the layer dislocation rock burst was explained and the energy radiation characteristics were analyzed. The SOS micro-seismic monitoring system was applied to observe the rock burst hazards about a mining face. The results show that P- and S-wave energy radiations produced by rock burst have directional characteristics. The energy radiation characteristics of the 22 rock bursts occurring on 79Z6 long-wall face are basically the same as theoretical results, that is, the ratio of S-wave energy of sensor 4 to 6 is about 1.5 and that of P-wave is smaller than 0.5. The consistency of the monitored characteristics of the energy radiation theoretically increases with the total energy increasing.

A Pilot-scale Demonstration of Reverse Osmosis Unit for Treatment of Coal-bed Methane Co-produced Water and Its Modeling

This study presents the first demonstration project in China for treatment of coal-bed methane(CBM) co-produced water and recycling.The work aims to provide a research and innovation base for solving the pollution problem of CBM extraction water.The reverse osmosis(RO) unit is applied to the treatment of CBM co-produced water.The results indicate that system operation is stable,the removal efficiency of the total dissolved solids(TDS) is as high as 97.98%,and Fe,Mn,and F-are almost completely removed.There is no suspended solids(SS) detected in the treated water.Furthermore,a model for the RO membrane separation process is developed to describe the quantitative relationship between key physical quantities-membrane length,flow velocity,salt concentration,driving pressure and water recovery rate,and the water recovery restriction equation based on mass balance is developed.This model provides a theoretical support for the RO system design and optimization.The TDS in the CBM co-produced water are removed to meet the "drinking water standards" and "groundwater quality standards" of China and can be used as drinking water,irrigation water,and livestock watering.In addition,the cost for treatment of CBM co-produced water is assessed,and the RO technology is an efficient and cost-effective treatment method to remove pollutants.

Establishment and Data Processing of High-Precision City Subsidence Monitoring Network by GPS Surveying Instead of Leveling

The feasibility of moni-toring the change of city settlementusing GPS surveying instead of level-ing is studied. A fiducial network anda monitoring network are establishedin Ningbo city. Two periods of GPSobservation are completed. Somemeasures are taken during the obser-vation in order to ensure to obtain thehigh-precise height component. TheSaastamoinen model is adopted in thedata processing of the dry componentpart of the tropospheric delay. Thewet component change of the tropo-spheric delay is estimated by stochasticprocesses model. When Bernese soft-ware is used to process the data, themillimeter level precision of heightmeasuring is achieved.

Adjusting precipitation measurements from the TRwS204 automatic weighing gauge in the Qilian Mountains, China

With the popularity of the automatic precipitation gauges in national weather stations,testing their performance and adjusting their measurements are top priorities. Additionally,because different climatic conditions may have different effects on the performance of the precipitation gauges, it is also necessary to test the gauges in different areas. This study mainly analyzed precipitation measurements from the single-Altershielded TRwS204 automatic weighing gauge(TRwS_(SA)) relative to the adjusted manual measurements(reference precipitation) from the Chinese standard precipitation gauge in a doublefence wind shield(CSPG_(DF)) in the Hulu watershed in the Qilian Mountains, China. The measurements were compared over the period from August 2014 to July2017, and the transfer function derived from the work by Kochendorfer et al.(2017 a) for correcting windinduced losses was applied to the TRwS_(SA) measurements. The results show that the average loss of TRwS_(SA) measurements relative to the reference precipitation decreased from 0.55 mm(10.7%) to 0.51 mm(9.9%) for rainfall events, from 0.35 mm(8.5%)to 0.22 mm(5.3%) for sleet events, and from 0.49 mm(18.9%) to 0.33 mm(12.7%) for snowfall events after adjustment. The uncorrected large biases of TRwS_(SA) measurements are considered to be mainly caused by specific errors of TRwS_(SA), different gauge orifice area and random errors. These types of errors must be considered when comparing precipitation measurements for different gauge types, especially in the mountains.

Spatial distribution and environmental characterization of sediment-associated metals from middle-downstream of Xiangjiang River,southern China

The contamination and environmental risk assessment of the toxic elements in sediments from the middle-downstream (Zhuzhou-Changsha section) of the Xiangjiang River in Hunan Province of China were studied. The results show that As, Cd, Pb and Zn are major contaminants in sediments, and average concentrations of these elements significantly exceed both the Control Standards for Pollutants in Sludge of China (GB4284-84) for agricultural use in acidic soils and the effect range median (ERM) values. The average concentrations of As, Cd and Pb in the river water slightly exceed the limit of Surface Water Environment Quality Standard (GB3838-2002). The concentrations of As and Cr in depth profiles extensively change, but slight changes are observed in Pb and Zn. Cd and Zn in most sediment samples can easily enter the food-chain and bring possible ecotoxicological risk to organisms living in sediments according to the risk assessment code.

Analysis of Fixed Site Leveling Abnormality at Hutubi Seismic Station

On the basis of the comparison data of Stage II of the tunnel site leveling project at Hutubi seismic station and the observation data of Stage IV of the site cross fault leveling project at Hutubi and the level observation data from the cross fault survey lines in Dafeng from 1987 to 2012,this paper analyses the variation rates of the tunnel site leveling observation results and the difference of annual change rates of the cross fault level observations at Hongshan seismic station in Hutubi. This paper concludes the reliability of the Ni004 optical level used by the station and puts forward a proposal based on the analysis. This paper also explores the cross fault leveling research on the ground deformation in the region concerned on the basis of the historical observation of the cross fault level at Dafeng and the comparison results of the tunnel site leveling observation in Hutubi.

Effects of Grain Angle on Reproducibility and Accurate Measurement of Moisture Content of Wood Samples Using a Pin-Style Moisture Meter

Studies were conducted on the effects of grain angle on reproducibility and accurate measurement of moisture content of four wood samples using a pin-style moisture meter. The wood samples were partitioned into four quadrants and moisture contents were measured along the grain direction in the first and second quadrants from 0 degree to 150 degrees insteps of 30 degrees. Experimental results indicated that the average moisture content remained constant as the grain angle increased. Repeated measurements of moisture content at different grain angles or points on the wood surface showed similar patterns of variation. Within-point standard deviations of the moisture contents were greater than between-point standard deviations. A non-destructive method of measuring moisture content at the same location or point on the wood surfaces could not be proposed because of the high variation of moisture content when repeated measurements were taken at the same point. Instead, accurate measurements of moisture content could be obtained at random positions within a radius of 30 mm from the point of intersection of the moisture content axis and the grain angle.

Measuring Bubble Levels in China＇s Urban Housing Market

In this paper we demonstrate that price-to-income ratio （PIR） is the most precise indicator of measuring bubble levels in China＇s urban hoasing market under current conditions. We have built a model to measure the reasonable PIR ceiling. Based on current mortgage rates, loan terms and down payment ratios, we conclude that the reasonable PIR for China ＇s urban residents should lie between 4.38-6.78 and should not exceed 7. 7hen, using statistical data, we calculate current PIR in China ＇s major cities. With reference to proper PIR, we conclude the existence of bubbles in China ＇s urban housing market; in particular, bubbles hace grown enormously large in some first-tier cities, which pose a huge financial risk. Based on the above analysis, we propose some policy suggestions to carefully deflate the bubbles in these housing markets.

Application of Equilibrium Partitioning Approach to the Derivation of Sediment Quality Guidelines for Metals in Dianchi Lake

For the past 20 years, numerous studies have been carried out on the application of equilibrium partitioning approach （EqPA） for the derivation of sediment quality guidelines （SQGs）. However, for metals, few Equilibrium-partitioning- based numerical SQGs have been developed or are currently available because of the confounding factors mediating the bioavailability of metals. A study was conducted at Dianchi Lake, which is a heavily eutrophicated lake on the Yunnan- Guizhou Plateau, China with the focus on the measurement of partitioning coefficient （Kp） and SQGs derivation and normalization to acid volatile sulfide （AVS）, fine material, and organic carbon. Using new normalization methods, SQGs were formulated for seven metals including copper, zinc, lead, cadmium, chromium, mercury, and arsenic in Dianchi Lake. In Dianchi Lake sediments, the fine material contributed 25.4%-36.0% to the SQG values, with the largest contribution to the SQG value of mercury; AVS contributed 2.9%-75.0% to the SQG values, with the largest contribution to the SQG value of cadmium. This indicated that the fine material and the AVS were the most important controlling factors to the bioavailability of mercury and caximium, respectively. The contribution of total organic carbon （TOC） to the SQG values of copper and leaxi was 3.8% and 7.1%, respectively, indicating that at relatively lower concentrations, the contribution of TOC was not significant. In addition to normalization methods, appropriate procedures for the application of EqPA including sample collection, storage, and analysis are also essential to improve the reliability of SQGs. The normalized Dianchi Lake SQGs were higher than most of the empirically based SQGs developed in North America, but lower than Hong Kong interim SQGs except for cadmium and arsenic. The differences could be attributed to the approaches used for derivation of SQGs and the water quality criteria adopted and the differences in the physical and chemical characteristics of the sediments.

Performance of Wuxi WWTP in China

In Wuxi Wastewater Treatment Plant, the Anaerobic, anoxic and oxic (A2/O) process was employed to remove the nitrogen and phosphorus, which exhibited the positive results of the high removal efficiency for phosphorus with a range of 67.7% to 89.9% and an average value of 78.0. The effluent of phosphorus met the national discharge standard. The removal of TN was effected by both BOD variation of influent and wastewater temperature. TN removal was in the range of 28.5% to 55.8% with an average value of 39.4%. The energy cost was 0.15 kWh(m3d)-1 or 1.35 kWh(kgBOD@d)-1. The annual average sludge production was 46.3 m3d-1, the annual average dosage for the dewatering was 40 kg d-1 .

Genetic analysis of land subsidence in Anshan

Land subsidence is a complex geological phenomenon which is concerned by the researchers at home and abroad. In this paper,the observation data from Anshan Second Order Leveling during 1987-[KG-*7]-1994,combined with the area of environmental engineering geology and geological conditions analysis shows that land subsidence in Anshan City is closely related to active tectonics,Quaternary strata and groundwater exploitation.

Environmental Effects of Water Quality of Melendiz Stream and Mamasin Dam Site in Aksaray City in the Central Anatolia of Turkey

The main purpose of this study was to determine the changes in the water quality of Melendiz and Karasu streams, which recharge the Mamasin dam, and to evaluate its environmental impacts on the dam site that provides drinking water and irrigation demand in Aksaray city in the Central Anatolia of Turkey. The field researches were focused on estimating the main sources of contamination, determining and evaluating the changes in the water quality due to the direct wastewater discharges into the Melendiz and Karasu rivers, which recharge the Mamasin dam sites. During the study, water samples were collected from Melendiz and Karasu stream and Mamasin dam, and then, the physical and chemical analyses of water samples were conducted. The relevant in-situ and laboratory analyses were carried out during the dry and wet seasons. The results of the analyses showed that in term of the surface water quality criteria in terms of NO3-N value of both rivers and dam waters, the water quality is always considered as the 1st class in Melendiz stream, the 2nd class in Karasu stream and the 3rd class in Mamasin dam lake. Whereas, in terms of NO4-N values of both rivers and dam waters, the water quality is always considered as the 1st class in Melendiz stream, the 2nd-3rd class in Karasu stream. The total organic carbon （TOC） range for Karasu river is usually from 20 mg/L to 40 mg/L. The high value of organic matter in the Karasu stream can be explained by the availability of intensive green wetlands around this water resource. Finally, the Ministry of Forest and Water Authority give some suggestions for estimating protection zones of Melendiz stream and Mamasin basin＇s area, such as using the results of environmental tracers to investigate the agricultural contamination, including more sophisticated applications of multiple-tracer analyses to evaluate the travel time of contaminants and estimate the boundary of protection zones.

Warmer-Get-Wetter or Wet-Get-Wetter? A Criterion to Classify Oceanic Precipitation

In this study,the temporal and spatial variations of observed global oceanic precipitation during 1979-2010 are investigated.It is found that the global trend in precipitation during this period varies at a rate of 1.5％/K of surface warming while the rate is 6.6％/K during 2006-2010.The precipitation is highly correlated with Sea Surface Temperature （SST） in both the temporal and the spatial patterns since the strong 1997-98 E1 Ni（n）o event.Considering the distributions of precipitation and SST,seven oceanic regions are classified and presented using the observed Global Precipitation Climatology Project （GPCP） data and Extended Reconstructed Sea Surface Temperatures,version 3 （ERSST.v3） data.Further examining the mechanisms of the classified oceanic precipitation regions is conducted using the Tropical Rainfall Measuring Mission （TRMM） satellite,GFDL-ESM-2G model precipitation and SST data and Hadley Center sea ice and SST version 1 （HadISST1） data.More than 85％ of global oceanic precipitations are controlled by either one or both of the warmer-get-wetter mechanism and wet-get-wetter mechanism.It is estimated that a 0.5 SST signal-to-noise ratio,representing the trend of SST time series to the standard deviation,is a criterion to distinguish the mechanism of a region.When the SST ratio is larger than 0.5,the precipitation of this region is controlled by the warmer-get-wetter mechanism.SST,rather than the humidity,is the pivotal factor.On the other hand,when the SST ratio is less than 0.5,the precipitation is controlled by the wet-get-wetter mechanism.The SST variability is a significant factor contributing to the precipitation variation.

Study on environmental impact of coal mining subsided water area in Huainan mining area

The subsided water areas with different times of subsidence are chosen to monitor the physicochemical indexes and heavy metal elements. The results indicate that subsided water areas are polluted in different degree. Some physicochemical indexes of subsided water areas are increased with the development of the subsidence and are changed with the changing of the season. The concentration of As, Cd, Cu, Pb, Se, Zn of subsided water areas is less than national fishery, and surface water quality standards of China , except Hg. And the quality of subsided water hasn＇t been polluted by heavy metal seriously. Analyzing and appraising the quality of the subsided water can give a reasonable data as basis in using the subsided water resource.