ANNUAL VARIATIONS OF TEMPERATURE ON FOUR URBAN UNDERLYING SURFACES AND FITTING ANALYSIS

Based on the observed 2-year temperature data for four kinds of typical urban underlying surfaces,including asphalt, cement, bare land and grass land, the annual variations and influencing factors of landsurface temperature are analyzed. Then fitting equations for surface temperature are established. It is shownthat the annual variation of daily average, maximum and minimum temperature and daily temperature rangeon the four urban underlying surfaces is consistent with the change in air temperature. The difference oftemperature on different underlying surfaces in the summer half year (May to October) is much moreevident than that in the winter half year (December to the following April). The daily average and maximumtemperatures of asphalt, cement, bare land and grass land are higher than air temperature due to theatmospheric heating in the daytime, with that of asphalt being the highest, followed in turn by cement, bareland and grass land. Moreover, the daily average, maximum and minimum temperature on the four urbanunderlying surfaces are strongly impacted by total cloud amount, daily average relative humidity andsunshine hours. The land surface can be cooled (warmed) by increased total cloud amount (relativehumidity). The changes in temperature on bare land and grass land are influenced by both the total cloudamount and the daily average relative humidity. The temperature parameters of the four land surfaces aresignificantly correlated with daily average, maximum and minimum temperature, sunshine hours, dailyaverage relative humidity and total cloud amount, respectively. The analysis also indicates that the range offitting parameter of a linear regression equation between the surface temperature of the four kinds of typicalland surface and the air temperature is from 0.809 to 0.971, passing the F-test with a confidence level of 0.99.

The influence of different underlying surface on sand-duststorm in northern China

In this paper, a quantitative research on the relationship between different underlying surface and sand-dust storm has been made by using 40 years meteorological data of five different types of underlying surface in northern China, which include farmland, grassland, sandland, gobi and salt crust. These metrological data comprise sand-dust storm days and strong wind days. By analyzing, we can find that there are certain correlations between the days of sand-dust storm and strong wind for different underlying surface, which has great influence on sand-dust storm. But there are pronounced differences in different types of underlying surface. The sand-dust storm days of grassland, gobi and salt crust, with smaller interannual variation are obviously less than strong wind days. On the other hand, the sand-dust storm days of farmland and sandland increase evidently, even in many years, are much more than strong wind days. The differences are mainly induced by the influencing mechanism of different underlying surface on sand-dust storm. Grassland, gobi and salt crust with stable underlying surface are not prone to sand-dust storm under strong wind condition. Whereas, the underlying surface of farmland and sandland is unstable, that is easy to induce sand-dust storm under strong wind condition.

Analysis on Thermal Environment of Underlying Surface and PM2.5 Concentration in Community Park of Beijing in Winter

Community park is one of the most important landscape spaces for urban people to live outdoors,and people’s perception of environmental microclimate is a direct factor affecting the use frequency and experience of community parks.In this paper,Shijingshan Sculpture Park of Beijing was taken as experimental object.Using the method of fi eld measurement,9-d winter test for 3 months was conducted in three kinds of landscape architecture spaces,including waterfront plaza,open green space and square under the forest.Via regression analysis method,the measured air temperature(Ta),relative humidity of air(RH),particulate matter(PM2.5)were analyzed.It is found that winter sunshine is main infl uence factor of garden microclimate,and there is a negative correlation between local temperature and humidity;local temperature and humidity can regulate the local PM2.5 concentration,and temperature shows negative correlation with PM2.5 concentration,while humidity shows positive correlation with PM2.5 concentration.Meanwhile,via comparative analysis of temperature,humidity and PM2.5 concentration in different types of garden spaces,the infl uence of different space forms,planting forms and materials on thermal environment of underlying surface and PM2.5 concentration was summarized,and design strategy was optimized,to be as benefi cial reference of reconstruction design of community parks.

The evapotranspiration and environmental controls of typical underlying surfaces on the Qinghai-Tibetan Plateau

To reveal the characteristics of evapotranspiration and environmental control factors of typical underlying surfaces(alpine wetland and alpine meadow)on the Qinghai-Tibetan Plateau,a comprehensive study was performed via in situ observations and remote sensing data in the growing season and non-growing season.Evapotranspiration was positively correlated with precipitation,the decoupling coefficient,and the enhanced vegetation index,but was energy-limited and mainly controlled by the vapor pressure deficit and solar radiation at an annual scale and growing season scale,respectively.Compared with the non-growing season,monthly evapotranspiration,equilibrium evaporation,and decoupling coefficient were greater in the growing season due to lower vegetation resistance and considerable precipitation.However,these factors were restricted in the alpine meadow.The decoupling factor was more sensitive to changes of conductance in the alpine wetland.This study is of great significance for understanding hydro-meteorological processes on the Qinghai-Tibetan Plateau.

Evidence for Multiple Underlying Fermi Surface and Isotropic Energy Gap in the Cuprate Parent Compound Ca2CuO2Cl2

The parent compounds of the high-temperature cuprate superconductors are Mott insulators.It has been generally agreed that understanding the physics of the doped Mott insulators is essential to understanding the mechanism of high temperature superconductivity.A natural starting point is to elucidate the basic electronic structure of the parent compound.Here we report comprehensive high resolution angle-resolved photoemission measurements on Ca_2CuO_2Cl_2,a Mott insulator and a prototypical parent compound of the cuprates.Multiple underl.ying Fermi surface sheets are revealed for the first time.The high energy waterfall-like band dispersions exhibit different behaviors near the nodal and antinodal regions.Two distinct energy scales are identified：a d-wave-like low energy peak dispersion and a nearly isotropic lower Hubbard band gap.These observations provide new information of the electronic structure of the cuprate parent compound,which is important for understanding the anomalous physical properties and superconductivity mechanism of the high temperature cuprate superconductors.

Analysis about the influence on the thermal regime in permafrost regions with different underlying surfaces

In the last several decades, the underlying surface conditions on the Qinghai-Tibet Plateau have changed dramatically, causing permafrost degradation due to climate change and human activities. This change severely influenced the cold regions environment and engineering infrastructure built above permafrost. Permafrost is a product of the interaction between the atmosphere and the ground. The formation and change of permafrost are determined by the energy exchange between earth and atmosphere system. Fieldwork was performed in order to learn how land surface change influenced the thermal regime in permafrost regions. In this article, the field data observed in the Fenghuo Mountain regions was used to analyze the thermal conditions under different underlying surfaces on the Qinghai-Tibet Plateau. Results show that underlying surface change may alter the primary energy balance and the thermal conditions of permafrost. The thermal flux in the permafrost regions is also changed, resulting in rising upper soil temperature and thickening active layer. Vegetation could prevent solar radiation from entering the ground, cooling the ground in the warm season. Also, vegetation has heat insulation and heat preservation functions related to the ground surface and may keep the permafrost stable. Plots covered with black plastic film have higher temperatures compared with plots covered by natural vegetation. The reason is that black plastic film has a low albedo, which could increase the absorbed solar radiation, and also decrease evapotranspiration. The ＂greenhouse effect＂ of transparent plastic film might effectively reduce the emission of long-wave radiation from the surface, decreasing heat loss from the earth＇s surface, and prominently increasing ground surface temperature.

Stormwater Quality Characteristics and Reuse Analysis of Different Underlying Surfaces at Wanzhou North Station

In response to the water shortage in Wanzhou North Station(WNS),the authors investigated the stormwater quality characteristics with different underlying surfaces of WNS and carried out stormwater reuse analysis in conjunction with the InfoWorks ICM model.The results show that during heavy,torrential,and moderate rainfall,the road stormwater runoff has the highest concentrations of pollutants,with an average EMC(event mean concentration)value of 206 mg/L for COD.For the square runoff,the average EMC values of COD,SS,TN,and TP are 108 mg/L,395 mg/L,2.113 mg/L,and 0.128 mg/L,in comparison,the average EMC values of the corresponding indexes for the roof runoff are 65 mg/L,212 mg/L,1.449 mg/L,and 0.086 mg/L,respectively,demonstrating their potential for reuse.The R2(coefficient of determination)of SS and COD in both roof and square runoff are greater than 0.85,with a good correlation,indicating that SS removal is the key to stormwater purification.InfoWorks ICM analysis shows that the recyclable volume of rainwater from WNS in 2018 is 29,410 m3,accounting for 61.8%of the total annual rainfall.This study is expected to provide an ideal reference for the stormwater management of public buildings in mountainous areas.

Analysis on gust factor of tropical cyclone strong wind over different underlying surfaces

Based on one year gradient wind data and the wind data of a strong typhoon observed by three meteorological towers located on the coast and at the inshore sea,the underlying surfaces of the meteorological towers were classified and the roughness lengths were calculated quantitatively.On the basis of strong wind characteristic representative assessment and sample selection on the wind data of strong typhoon Hagupit,the gust factor variation characteristics of tropical cyclones under different underlying surfaces were analyzed.The observed fact and variation rule were found as follows:1) The roughness lengths under neutral atmospheric condition which were calculated using logarithmic wind profile fitting based on the observation data can describe the slight change of the underlying surface objectively.2) The gust factor of strong typhoon wind didn't have variation trends with wind speed.But the variation amplitude of the gust factor was rather large over rough underlying surface which had pronounced effect on the numerical design of structural engineering.3) The variation of the gust factor with height satisfied power law or logarithmic law.The power law fitting was more suitable for smooth underlying surface while the logarithmic fitting was better over rough underlying surface.4) The observation data also suggested that the relationship between gust factor and roughness length can be described by power or linear equation.5) The gust factor observed in this typhoon case was different from the gust factor recommended by WMO:The gust factor of the offshore wind came from rough underlying surface was higher than the value recommended by WMO while the gust factor of the onshore wind came from smooth underlying surface is less than the WMO recommended value.

Characteristics of Near Surface Winds over Different Underlying Surfaces in China: Implications for Wind Power Development

Accurate wind and turbulence information are essential to wind energy research and utilization, among which wind shear and turbulence intensity/scale have seldom been investigated. In this paper, the observational data from the100-m high wind towers in Xilinhot in Inner Mongolia(2009–10; grassland region), Huanghua in Hebei Province(2009–10; coastal flat region), and Xingzi County in Jiangxi Province(2010–11; mountain–lake region) are used to study the variations in near surface winds and turbulence characteristics related to the development of local wind energy over different underlying surfaces. The results indicate that(1) the percentage of the observed wind shear exponents exceeding 0.3 for the grassland region is 6%, while the percentage is 13% for the coastal flat region and 10%for the mountain–lake region. In other words, if the wind speed at 10 m is 10 ms^(–1), the percentage of the wind speed at 100 m exceeding 20 ms^(–1) for the grassland region is 6%, while the percentage is 13% for the coastal flat region and 10% for the mountain–lake region.(2) In terms of the turbulent intensity in the zonal, meridional, and vertical directions(I_u, I_v, and I_w, respectively), the frequencies of I_v/I_u < 0.8 in the grassland, coastal flat, and mountain–lake regions are 23%–29%, 32%–38%, and 30%–37%, respectively. Additionally, the frequencies of I_w/I_u < 0.5 in the grassland, coastal flat, and mountain–lake regions are 45%–75%, 52%–70%, and 43%–53%, respectively. The frequencies of I_v/I_u < 0.8 and Iw/I_u < 0.5 in each region mean that I_u is large and the air flow is unstable and fluctuating,which will damage the wind turbines. Therefore, these conditions do not meet the wind turbine design requirements,which must be considered separately.(3) At 50-and 70-m heights, the value of the turbulence scale parameter Λ in the grassland region is greater than that in the coastal flat region, and the latter is greater than that in the mountain–lake region. Therefore, under the same conditions, some parameters, e.g., the extreme directional change and extreme operating gust at the hub height in the grassland region, are greater than those in the coastal flat region,which are greater than those in the mountain–lake region. These results provide a reference for harnessing local wind energy resources and for the selection and design of wind turbines.

Numerical Simulation Experiment of Land Surface Physical Processes and Local Climate Effect in Forest Underlying Surface

Based on the basic principles of atmospheric boundary layer and plant canopy micrometeorology, a forest underlying surface land surface physical process model and a two-dimensional atmospheric boundary layer numerical model are developed and numerical simulation experiments of biosphere and physiological processes of vegetation and soil volumetric water content have been done on land surface processes with local climate effect. The numerical simulation results are in good agreement with realistic observations, which can be used to obtain reasonable simulations for diurnal variations of canopy temperature, air temperature in canopy, ground surface temperature, and temporal and spatial distributions of potential temperature and vertical wind velocity as well as relative humidity and turbulence exchange coefficient over non-homogeneous underlying surfaces. It indicates that the model developed can be used to study the interaction between land surface process and atmospheric boundary layer over various underlying surfaces and can be extended to local climate studies. This work will settle a solid foundation for coupling climate models with the biosphere.

Regulation characteristics of underlying surface on runoff regime metrics and their spatial differences in typical urban communities across China

The regulation and spatial differences of urban runoffs are of great concern in contemporary hydrological research.However,owing to a shortage of basic data sources and restrictions on urban hydrological simulation functions,simulating and investigating the regulation mechanism behind rainfall-runoff processes remain significantly challenging.In this study,the Time Variant Gain Model(TVGM),a hydrological nonlinear system model,was extrapolated to the hydrodynamic model of an urban drainage network system by integrating it with the widely used Stormwater Management Model(SWMM)to adequately simulate urban runoff events while considering various underlying surfaces and runoff routing modes,such as surface,drainage network and river runoff,in urban regions(i.e.,TVGM-SWMM).Moreover,runoff events were characterized using the following four runoff regime metrics:runoff coefficient,capture ratio of annual runoff volume,standardized flood timescale,and the ratio of occurrence time differences between flow and rainfall peak to event duration(peak flow delay time).The characteristics and spatial differences of urban runoff regulations were investigated,and the key impact factors and their relative contributions were identified using multivariate statistical analyses.Four communities were selected as our study areas,consisting of communities from Beijing,Shenzhen,Wuhan,and Chongqing.Our results showed that the TVGM-SWMM performed considerably better than SWMM alone.The comprehensive simulation accuracy of 60%of the events(12/20)improved by 4-86%,with the bias improving the most,followed by the efficiency coefficient.Barring the runoff coefficient,significant spatial differences were identified at the patch scale for the runoff regime metrics,with differences of 0.43,0.22,and 0.16(p<0.05).The key impact factors were the pipe length(r=0.51)in the drainage network system and the forest area ratios(r=0.56),sponge measures(r=0.52),grassland(r=0.48),and impervious surface(r=0.46)in the underlying surfaces.The contributions of the drainage network system and the underlying surfaces were 4.27%and 37.83%,respectively.Regulation in the Beijing community,dominated by grassland regulation,delayed and reduced the peak flow and total runoff volume.In the Shenzhen community,sharp and thin runoff events were mainly generated by impervious surfaces and were not adequately regulated.Forest regulation was the dominant regulation type in the Wuhan community,which reduced the total runoff volume and delayed the peak flow.Waterbody regulation was the primary regulation type in the Chongqing community,which reduced the total runoff volume and peak flow.This study aims to introduce a comprehensive theoretical and technical assessment of the hydrological effects of urbanization and the performance of sponge city construction and provide a reference for urban hydrological model improvements in China.

Pulsatory characteristics of wind velocity in sand flow over typical underlying surfaces

Pulsatory characteristics of wind velocity in sand flow over Gobi and mobile sand surface have been investigated experimentally in the wind tunnel. The primary goal of this paper is to reveal the relation- ship between pulsatory characteristics of instantaneous wind speed in sand flow and the motion state of sand grains. For a given underlying surface, pulsation of wind velocities in sand flow on different heights has a good correlation. As the space distance among different heights increases, fluctuation of instantaneous wind speed presents a decreasing trend and its amplitude is closely related to the mo- tion state of sand grains and their transport. Pulsatory intensity increases with the indicated wind speed, but its relative value does not depend on it, only agrees with height.

Observational study of land-atmosphere turbulent flux exchange over complex underlying surfaces in urban and suburban areas

Based on observation data from urban observation stations in Nanjing and Suzhou at two heights in the roughness sublayer above the canopy and observation data at three heights in the SORPES station at the Xianlin Campus of Nanjing University in a suburban area,the of land-atmosphere turbulent flux exchange and the energy balance over complex underlying surfaces were analyzed.The results indicated that in the roughness sublayer above the canopy,the nearsurface momentum flux,sensible heat flux,and latent heat flux increase with height,and the observation value of the surface albedo increases with height.However,the observation value of the net radiation decreases with height,thus resulting in a change in the urban surface energy budget with height.At the SORPES station in the Xianlin Campus of Nanjing University located in a hilly area,the momentum flux,sensible heat flux,and latent heat flux of the ground observation field significantly differed from those of the two heights on the tower,while the two heights on the tower were extremely close.These results indicate that the flux observation over the complex underlying surface exhibits adequate local only when it is conducted at a higher altitude above the ground.The turbulent flux observation results at a lower altitude in urban areas are underestimated,while the turbulent flux observation results near the surface produce a large deviation over the underlying hilly complex.

煤矿覆岩离层注浆减沉技术研究及应用

针对门克庆煤矿11-3101工作面铁路下压煤问题,为提高煤炭资源回收率,应用离层注浆减沉技术减小地表下沉,通过室内试验测试了不同配比充填料浆的流变特性,确定了合适的料浆配比,同时构建采动覆岩离层演变力学模型,提出了离层动态发育位置及离层开度预测方法。研究结果表明:11-3101工作面从下往上将会产生四个离层,分别位于工作面顶板上方45.42、228.38、337.19、363.99 m处;离层开度从下到上依次为2.62、1.49、1.39和1.33 m,开度随着层高的增长而递减;注浆压力为6.5 MPa,注采比大于45%时,地表倾斜变形值小于3 mm/m,现场监测结果显示铁路路基最大沉降量仅58.72 mm,注浆减沉效果显著。

月球熔岩管探测与开发方案设计

在总结前期探测成果和前人研究的基础上,结合对地球熔岩管洞穴的实地考察,深入分析月球熔岩管洞穴的探测开发价值与挑战。结合月球遥感探测数据,针对不同洞口构造的熔岩管,以中丰富海及静海两个典型熔岩管洞穴为案例,构建了由月面平台、探测器及自主机器人等组成的联合探测方案。围绕未来建设月球熔岩管洞穴基地的目标,深入分析熔岩管洞穴开发建设需求与挑战,进一步提出了熔岩管洞穴内部场坪建设、通信能源部署以及居住设施建造方案。

自适应区域生长的复杂曲面点云分割方法

机器人自动加工复杂曲面之前,需要对待作业目标曲面进行区域划分,以适配不同的工艺参数。针对现有方法分割复杂曲面点云产生的过分割和欠分割问题,提出一种自适应区域生长的复杂曲面点云分割方法。首先,设计基于动态平滑阈值的自适应生长准则,用于复杂曲面对象的点云分割,以减少过分割现象;其次,提出欠分割判断准则,以判定分割后的点云集,过滤出欠分割区域;然后,将欠分割区域重分割,直到不存在欠分割区域;最后,以扫描陶瓷洁具素坯得到的复杂曲面点云为实验对象,测试了提出方法对复杂曲面点云的分割效果。实验结果表明,提出方法的分割精度达92.63%、召回率达98.89%、综合评价指标F1分数达95.66,能有效且完备地分割出复杂曲面点云的各个区域。

响应曲面法优化山西某煤下铝土矿浮选提质试验研究

为开发利用山西某煤下高硫铝土矿,在矿石性质研究的基础上进行反浮选脱硫脱碳试验以达到除杂提质的目标。在磨矿细度为-0.074 mm含量为70.12%、浮选pH值为8.5的条件下,利用Design-Expert软件的Box-Behnken优化得到反浮选的最佳药剂制度为硫酸铜用量为27.48 g/t、丁基黄药用量为154.33 g/t、松醇油为45.11 g/t,在上述条件下实际试验所得产率为90.14%、硫含量为0.39%的铝精矿指标,与软件拟合所得方程的预测结果(产率为90.25%,硫含量为0.40%)基本吻合。原矿通过选取优化后条件进行“一粗一精三扫”的闭路浮选提质流程处理后,获得了产率为97.32%、S含量为0.32%、C含量为0.15%的铝精矿以及产率为2.68%、S含量为35.77%的硫精矿,实现了对煤下铝土矿的综合利用。

静-动荷载作用下欠固结软土盾构隧道长期沉降与最优埋深计算方法

为研究地表堆载、列车荷载和欠固结软土固结沉降联合作用下的盾构隧道长期沉降数值及其变化规律问题,依托广州市南沙至珠海(中山)城际项目,利用PLAXIS建立有限元模型计算外部作用下的盾构隧道长期沉降值,通过单因素敏感性分析和非线性拟合方法分析各影响因子对长期沉降的影响并确定5种关键影响因子,提出长期沉降与最优埋深计算方法。研究结果表明:1)超固结比与隧道埋深对长期沉降影响最大,上部堆载荷载值、荷载作用宽度和列车荷载影响次之,而荷载距离、列车速度和渗透系数对长期沉降的影响可以忽略不计;2)为求解盾构隧道长期沉降值,提出静-动荷载作用下欠固结软土盾构隧道的长期沉降计算方法,计算值与模拟值吻合良好;3)将国家规范中盾构隧道变形控制值(20 mm)作为隧道沉降控制值,代入长期沉降计算公式,反推得到隧道最优埋深计算公式,其中软土欠固结特性对最优埋深影响最大。为有效控制长期沉降发展,建议将隧道整体置于较好的土层中,如需设置在淤泥及淤泥质土层中,则应进行地基处理、排水固结,以改善土体欠固结程度。

地铁隧道盾构下穿既有砌体人防工程影响研究

以郑州市某区间隧道下穿砌体人防工程为例,采用三维有限元对实际工程进行建模,对盾构双隧道下穿加固区砌体人防工程变形进行分析,考察盾构隧道施工产生的地表沉降及水平位移。结果表明,水泥砂浆填充显著减小了既有砌体人防结构位移,未填充区结构位移显著大于填充区,但都在允许范围内;双隧道相继开挖使得地表沉降曲线呈现不同姿态。通过有限元模型对地层及结构变形进行分析,可为今后类似盾构穿越施工提供参考。

结膜下注射5-氟尿嘧啶在中青年复合式小梁切除手术中的应用

目的探讨在青光眼小梁切除术中结膜下注射5-氟尿嘧啶,对于易瘢痕化的中青年青光眼患者的远期治疗效果和眼表保护作用。方法研究2021年1月至2021年12月在常熟市第一人民医院行青光眼手术的患者39例(58只眼),分为结膜下注射组(18只眼),棉片组(20只眼)和对照组(20只眼)。其中对照组术中行小梁切除术+巩膜可调整缝线;结膜下组术中行小梁切除术+巩膜可调整缝线,同时术毕前结膜下注射5mg 5-氟尿嘧啶;棉片组行小梁切除术+巩膜可调整缝线,结膜瓣下方放置浸湿5-氟尿嘧啶棉片。术后进行共计6个月的随访,比较术后眼压、滤过情况、术后有效率情况和眼表疾病指数量表(ocular surface disease index,OSDI)评分情况。结果结膜下注射组和棉片组术后1个月、6个月眼压均较对照组低,且术后半年有效率高于对照组,安全性良好。同时,结膜下注射组术后OSDI评分显著低于棉片组和对照组。结论青光眼小梁切除术毕前结膜下注射5氟尿嘧啶,可以改善瘢痕化的中青年青光眼患者的手术效果、成功率和眼表症状且具有相当的安全性。