Research Status of Water Quality Criteria and Standards and Analysis on the Transformation Methods

Under the vision of development for the new era,China has entered a stage of high-quality economic development and an important window period in which we have the conditions and ability to address the prominent issue of economic development and ecological protection in a coordinated way.However,all kinds of environmental benchmark values in China are lacking and need to be constantly supplemented and improved.Therefore,exploring and putting forward a simple and efficient method for the transformation of environmental criteria into environmental standards is an important basis for the rapid establishment of relevant environmental criteria system and the effective promotion of the development of environmental standards system towards a scientific and reasonable direction.In this paper,the water environment is taken as the research object.By analyzing the research progress of environmental criteria and standards at home and abroad,and the foreign method of transforming environmental criteria into environmental standards,combined with the problems faced in the process of transforming environmental criteria into environmental standards in China,an effective method to transform China's environmental criteria into environmental standards is analyzed.After analysis and comparison,it is found that the pollution reduction accounting method could achieve their simple and efficient conversion.Under the premise of obtaining environmental criteria for certain pollutants,environmental criteria for certain pollutants could be obtained by distributing pollutants reduction costs,and accounting economic benefits after reaching standard,thus obtaining the environmental standard of this type of pollutant,which provides reference to determine the environmental standard limits of such pollutants.

WATER RESOURCES TRANSFORMATION AND WATER QUALITY VARIATION IN THE URUMQI RIVER BASIN

Like other inland basins in arid regions, the natural vertical zones create special conditions for water resources transformation in the Urumqi River Basin. In the course of water resources transformation and utilization, the chemical composition and degree of mineralization are influenced by both geographic conditions and human activities. Although the Urumqi River is rather small in runoff and rather short in flow distance, the water quality changes substantially along the river. However, ion concentrations of surface and ground water in the whole basin are relatively low, generally less than 1 g/L. Therefore, the basin is good at providing low-mineralized water. The pollution is not so serious and the water impurity does not surpass the national standard for drinking. As long as people are conscious with protecting water quality and reducing the further water pollution, it is possible for harm of the slight pollution to be eliminated.

CHARACTERISTICS OF WATER TRANSFORMATION AND ITS EFFECTS ON ENVIRONMENT IN THE ARID REGION —A case study in Alar irrigation region of Xinjiang, China

The characteristics of water balance in arid regions is that the streams are formed in mountain area and continuously evaporates and infiltrates in the process of flowing to plain area, streams finally disappear in the desert or flow into the lakes, which are the low reaches of the rivers. But the distribution and transformation of water in Xinjiang, China have changed under the influences of human activities. The influences of human activities take place in a short time and regionally, especially in arid land where water is the key factor of environment. Water inside of oasis has increased, and water out of oasis or at the lower reaches of the river has decreased. Human activities have caused the environment changes in both positive and negative aspects by changing the circulation and distribution of water. Under the influence of human activities, oases in Xinjiang have expanded, meanwhile some lakes have contracted desertification is serious, natural vegetation has declined and natural environment out of oasis has degenrated.

Numerical Simulation Analysis of the Transformer Fire Extinguishing Process with a High-Pressure Water Mist System under Different Conditions

To thoroughly study the extinguishing effect of a high-pressure water mist fire extinguishing system when a transformer fire occurs,a 3D experimental model of a transformer is established in this work by employing Fire Dynamics Simulator(FDS)software.More specifically,by setting different parameters,the process of the highpressure water mist fire extinguishing system with the presence of both diverse ambient temperatures and water mist sprinkler laying conditions is simulated.In addition,the fire extinguishing effect of the employed high-pressure water mist system with the implementation of different strategies is systematically analyzed.The extracted results show that a fire source farther away fromthe centerline leads to a lower local temperature distribution.In addition,as the ambient temperature increases,the temperature above the fire source decreases,while the temperature and the concentrationof theupperflue gas layer bothdecrease.Interestingly,after thehigh-pressurewatermist sprinkler begins to operate,both the temperature distribution above the fire source and the concentration of the flue gas decrease,which indicates that the high-pressure water mist system plays the role of cooling and dust removal.By comparing various sprinkler laying methods,it is found that the lower sprinkler height has a better effect on the temperature above the fire source,the temperature of the upper flue gas layer,and the concentration of the flue gas.Moreover,when the sprinkler is spread over thewhole transformer,the cooling effect on both the temperature above the fire source and the temperature of the upper flue gas layer is good,whereas the change in the concentration of the flue gas above the fire source is not obvious compared to the case where the sprinkler is not fully spread.

Tuning electrochemical transformation process of zeolitic imidazolate framework for efficient water oxidation activity

Metal-organic frameworks(MOFs)have been widely studied as efficient electrocatalysts for water oxidation due to their tunable structure and easy preparation.However,the rational design of MOFs-based electrocatalysts and fundamental understanding of their structural evolution during oxygen evolution reaction(OER)remain critical challenges.Here,we report a facile approach to tune the structural transformation process of the Co-based zeolitic imidazolate framework(ZIF)during the OER process by using water molecules as a vacancy promoter.The modified ZIF catalyst accelerates the structural transformation from MOF precursor to electrochemical active species and simultaneously enhances the vacancy density during the electrochemical activation process.The optimized electrocatalyst exhibits an extremely low overpotential 175 mV to deliver 10 mA cm^(-2) and superior durability(100 h)at 100 mA cm^(-2).The comprehensive characterization results reveal the structural transformation from the initial tetrahedral Co sites to cobalt oxyhydroxide(CoOOH)and the formation process of oxygen vacancies(CoOOH-Vo)at a high anodic potential.These findings represent a promising way to achieve highly active MOF-based electrocatalysts for water oxidation.

Water adsorption performance of UiO-66 modified by MgCl_(2) for heat transformation applications

UiO-66 is a potential material for adsorption heat transformation(AHT)with high specific surface area,and excellent thermal and chemical stability.However,the low water adsorption capacity of UiO-66 in the low relative pressure range(0<P/P_(0)<0.3)limits its application in AHT.We prepare the UiO-66 modified by MgCl_(2)through using the solvothermal method and impregnation method,and study their water vapor adsorption performances and heat storage capacities.Attributed to the extremely high saturated water uptake and excellent hydrophilicity of MgCl_(2),the water adsorption performance of UiO-66 is improved,although the introduction of MgCl_(2)reduces its specific surface area and pore volume.The water adsorption capacity at P/P_(0)=0.3 and the saturated water adsorption capacity of the UiO-66(with MgCl_(2)content of 0.57 wt%)modified by the solvothermal method are 0.27 g/g and 0.57 g/g at 298 K,respectively,which are 68.8%and 32.6%higher than the counterparts of pure UiO-66,respectively.Comparing with pure UiO-66,the water adsorption capacity of the UiO-66(with MgCl_(2)content of 1.02 wt%)modified by the impregnation method is increased by 56.3%and 14.0%at the same pressure,respectively.During 20 water adsorption/desorption cycles,the above two materials show high heat storage densities(~1293 J/g and 1378 J/g).Therein,the UiO-66 modified by the solvothermal method exhibits the excellent cyclic stability.These results suggest that the introduction of an appropriate amount of MgCl_(2)makes UiO-66more suitable for AHT applications.

Preparation and Phase Transformation Behavior of Boehmite via Heat Treatment in Water Vapor

Boehmite was prepared under heat treatment in water vapour, and the phase transformation of gibbsite heat-treated at various temperatures was investigated. The sample was characterized by scanning electron microscopy(SEM), X-ray diffraction (XRD), thermogravimetry and differential thermalanalysis (TG-DTA), fourier transform infrared (FTIR),and BET surface area.Effect of temperature on preparation was studied in the range of 155°–195°.With the increase in temperature, transformation of gibbsite into crystalline boehmites took place as indicated by the X-ray diffraction (XRD). The shape of the grains in the prepared sample was cube-like morphology.In water vapour gibbsite transform into boehmite by a dissolution - precipitation mechanism.

基于Transformer语义分割模型的露天矿场识别

露天矿场是生产建设项目水土保持信息化监管的重要对象,对其范围的高效精准识别对于监测非法违规开采行为,加强开采过程中的水土流失预防与治理具有重要意义。基于Transformer深度学习模型提出了露天矿场的遥感影像智能识别方法,并在四川省宜宾市的露天矿场影像数据集上与常用的基于卷积神经网络的深度学习识别方法进行了实验对比。结果表明:该方法对露天矿场范围识别的精确率、召回率、F1-score和IoU指标分别达到91.25%,90.66%,90.95%和83.41%,能够满足水土保持遥感监管的精确度要求;在识别精确度和识别效果上优于对比方法,在运行效率上与对比方法保持在同一数量级,表现出较强的应用价值。该方法在大区域露天矿场范围快速准确识别方面有推广应用潜力。

Transformation among precipitation,surface water,groundwater,and mine water in the Hailiutu River Basin under mining activity

Coal mining has changed the hydrogeological conditions of river basins,and studying how the relationship among different types of water body has changed under the influence of coal mining is of great significance for understanding the regional hydrological cycle.We analyzed the temporal and spatial distribution of hydrochemical properties and environmental isotopes in the Hailiutu River Basin(HRB),China with a mixed model.The results showed that:(1)human activity(e.g.,coal mining and agricultural production)causes considerable changes in the hydrochemical properties of surface water in and around the mining areas,and leads to significant increases in the concentrations of Na^(+)and SO_(4)^(2-);(2)precipitation is the main source of water vapour in the HRB.The transformation between surface water and groundwater in the natural watershed is mainly affected by precipitation;and(3)in the mining areas,the average contribution rates of precipitation to the recharge of surface water and groundwater increased by 2.6%-7.9%and 2.7%-9.9%,respectively.Groundwater in the Salawusu Formation constitutes up to 61.3%-72.4%of mine water.Overall,this study is beneficial for quantifying the effects of coal mining on local hydrological cycles.The research results can provide a reference for local water resources management and ecological environment improvement.

Wave Height Transformation and Set-up Between A Submerged Permeable Breakwater and A Seawall

In this study, we investigated wave transformation and wave set-up between a submerged permeable breakwater and a seawall. Modified time-dependent mild-slope equations, which involve parameters of the porous medium, were used to calculate the wave height transformation and the mean water level change around a submerged breakwater. The numerical solution is verified with experimental data. The simulated results show that modulations of the wave profile and wave set-up are clearly observed between the submerged breakwater and the seawall. In contrast to cases without a seawall, the node or pseudo-node of wave height evolution can be found between the submerged breakwater and the seawall. Higher wave set-up occurs if the nodal or pseudo-nodal point appears near the submerged breakwater. We also examined the influence of the porosity and friction factor of the submerged permeable breakwater on wave transformation and set-up.

Impact of Urban Land Transformation on Water Bodies in Srinagar City, India

Human actions rather than natural forces are the source of most contemporary changes in the state and flows of the biosphere. Understanding these actions and the social forces that drive them is crucial to understanding, modelling and predicting local, regional as well as global environmental change and also for managing and responding to such change. The present study investigates the patterns of urban land transformation in Srinagar City, which lies in fragile hill eco-system of Kashmir valley. The results points towards unplanned and haphazard urban expansion and transformation. These transformations have severely destroyed the water bodies both in terms of area as well as its quality.

Effects of muddy water irrigation with different sediment gradations on nitrogen transformation in agricultural soil of Yellow River Basin

Muddy water irrigation has been widely practiced in the Yellow River Basin for agricultural production and is an important method of economical and intensive utilization of water resources.In this study,the effects of sediment gradation,sand content,and soil moisture content on nitrogen(N)transformation were studied through a series of experimental tests.The results indicated that muddy water irrigation significantly affected agricultural soil physical and biological properties as well as N transformation.Soil bulk density,total porosity,pH,and microbial enzyme activities significantly correlated with N transformation as affected by the interaction between sediment and soil moisture.Sediment addition generally increased the soil bulk density and reduced the soil porosity and pH significantly,and the optimum moisture for promotion of the N transformation rate was 80%of the water-filled pore space.Therefore,muddy water irrigation has a potentially long-term influence on agricultural N cycles in semi-arid regions of northwestern China.This could provide a theoretical basis for scientific and rational use of muddy water for irrigation.

Water Wave Focusing Using Coordinate Transformation

In this paper, wave focusing based on a coordinate transformation is proposed. It is known that the 2-dimensional wave equation which governs a shallow water problem in a potential theory can keep invariance under coordinate transformation. Once equivalent medium parameters are obtained so as to keep the invariance, wave rays can be arbitrarily designed. We show the design of equivalent medium for wave squeezing to focus waves on a specific domain. Numerical computations are carried out by a finite element based software COMSOL Multiphysics. Results show good agreement between predictions from the theory and computations. It can be applied for a wide range of frequency because the proposed method is able to be applied regardless of the frequency.

Transformation of Nonlinear Surface Gravity Waves under Shallow-Water Conditions

This article describes transformation of nonlinear surface gravity waves under shallow-water conditions with the aid of the suggested semigraphical method. There are given profiles of surface gravity waves on the crests steepening stages, their leading edges steepening. There are discussed the spectral component influence on the transformation of surface wave profile.

Numerical Simulation of Nonlinear Surface Gravity Waves Transformation under Shallow-Water Conditions

This work considers the problems of numerical simulation of non-linear surface gravity waves transformation under shallow bay conditions. The discrete model is built from non-linear shallow-water equations. Are resulted boundary and initial conditions. The method of splitting into physical processes receives system from three equations. Then we define the approximation order and investigate stability conditions of the discrete model. The sweep method was used to calculate the system of equations. This work presents surface gravity wave profiles for different propagation phases.

Moisture Movement and Transformation Law under Soil Moisture Conserving Irrigation in Winter Wheat Field

[Objective] The aim was to provide theoretical basis for field moisture conserving irrigation.[Method] With Xiaoyan No.6 as tested material,three different kinds of mulching irrigation treatments were carried out （straw mulching;plastic mulching;PAM control adjustment mulching）.With non-mulching treatment as control,moisture conserving effect of different treatments were compared.[Result] The results showed that the water consumption of winter wheat under different soil moisture conservation treatments was low at earlier stage and later stage,but high at mid-stage,which was consistent with the water consumption law of control.There were some differences in terms of consumption intensity because of irrigation schedule and growth condition;soil moisture conservation treatments could restrain ineffective evaporation of soil moisture before anthesis.We also found that the variation of soil moisture at depth of 0-20 cm in PAM and control treatment was dramatic.The soil moisture of the former was lower than the latter at the depth of 0-20 cm,but higher at the depth of 20-50 cm.The difference of soil moisture at the depth of 0-50 cm was significant.[Conclusion] Plastic mulching and straw mulching could restrain evaporation effectively.

Supercritical water syntheses of transition metal-doped CeO_2 nano-catalysts for selective catalytic reduction of NO by CO:An in situ diffuse reflectance Fourier transform infrared spectroscopy study

In the present study,we synthesized CeO2 catalysts doped with various transition metals(M=Co,Fe,or Cu)using a supercritical water hydrothermal route,which led to the incorporation of the metal ions in the CeO2 lattice,forming solid solutions.The catalysts were then used for the selective catalytic reduction(SCR)of NO by CO.The Cu‐doped catalyst exhibited the highest SCR activity;it had a T50(i.e.,50%NO conversion)of only 83°C and a T90(i.e.,90%NO conversion)of 126°C.Such an activity was also higher than in many state‐of‐the‐art catalysts.In situ diffuse reflectance Fourier transform infrared spectroscopy suggested that the MOx‐CeO2 catalysts(M=Co and Fe)mainly followed an Eley‐Rideal reaction mechanism for CO‐SCR.In contrast,a Langmuir‐Hinshelwood SCR reaction mechanism occurred in CuO‐CeO2 owing to the presence of Cu+species,which ensured effective adsorption of CO.This explains why CuO‐CeO2 exhibited the highest activity with regard to the SCR of NO by CO.

融合Transformer与残差通道注意力的恶劣场景水位智能检测方法

精准感知水位信息变化是实现精细水务管控和洪涝灾害的关键环节之一,而低照度、雾霾、雨雪、冰冻、波浪、镜头抖动等恶劣场景给水位检测带来极大挑战。针对现有方法中难以实现水位精准检测难题,构建一种融合Transformer与残差通道注意力机制的Unet模型(TRCAM-Unet),进而提出基于TRCAM-Unet的恶劣场景水位智能检测方法。关键技术包括通过全尺度连接结构实现多层次特征融合,通过Transformer模块强化区域特征的关联性,通过残差通道注意力模块强化有用信息的表达并削弱无用信息的干扰。相关试验和实践表明,TRCAM-Unet取得了98.84%MIOU评分与99.42%的MPA评分,在约150 m距离外水位检测最大误差不超过0.08 m,水位偏差均值(MLD)仅有1.609×10^(-2)m,优于Deeplab、PSPNet等主流语义分割算法。研究结果对解决恶劣场景下水位精准检测难题及洪涝灾害预警具有重要应用价值。

融合Swin-Transformer网络模型的水体高光区域提取

在强光的照射下,水体的镜面反射往往会对遥感影像产生很大影响,其主要表现就是在图像上产生大小不同、形状各异的亮斑。这些亮斑附近的地物信息基本上都被淹没,对后期的影像分析会造成不同程度的影响,因此对这些亮斑的检测识别就显得尤为重要。文章以DeeplabV3plus为主要网络,提出一种融合Swin-Transformer模块的网络模型。该模型将Swin-Transformer网络作为一个模块与卷积骨干网络并行提取特征。提取出的两类特征经上采样后进行特征融合,再经多次卷积等实现了水体亮斑的识别与分割。实验结果表明,该模型能够对不同类型、不同形状的水体亮斑进行识别分割,其平均交并比为93.44%。

一种改进Swin Transformer网络的资源三号水体提取方法

针对传统的水体指数法和监督分类法在对卫星影像进行水体提取时经常出现错分的问题,提出一种改进Swin Transformer网络的资源三号影像水体提取方法,并对其特征金字塔的构建进行优化。其中,结合PANet算法原理快速融合特征金字塔顶层信息和底层信息,通过融合不同尺度的信息提高对水体特征提取的效果;利用Swin Transformer网络包含的滑动窗口分割和循环位移操作来减少训练时的计算复杂度。通过混淆矩阵计算得到该方法对城区、郊区和山区水体提取结果的总体精度、Kappa系数、F1-score指数,分别在90.14%~96.52%之间、0.80~0.88之间、0.81~0.87之间,证明该方法对资源三号卫星影像进行水体提取的有效性与可靠性。