In order to scientifically reveal the working performance of fissure grouting slurry calcined ginger nuts modified by earthen site's soil,we analyzed the effects of different water solid ratios,slurry ratios,slurry compositions(calcined ginger nuts modified by natural earthen site's soil(CGN-N),calcined ginger nuts modified by grinding earthen site's soil(CGN-G))on the rheological performance,fluidity and bleeding stability of slurry.The results showed that the consistency coefficient of CGN-G and CGN-N slurry increased with the decrease in the water-solid ratio and slurry ratio,while the fluidity and bleed-ing rate behaved in the opposite.Compared with CGN-N slurry,the theological index,fluidity and bleed-ing rate of CGN-G slurry were reduced by 3.28％,7.50％and 83.62％on average,and the consistency co-efficient was increased by 3.28％on average.Scanning electron microscope and particle analysis revealed that particle micro-morphology,specific surface area and particle stacking state were important factors af-fecting the working performance of its slurry.It is proved that CGN-G slurry has a more balanced work-ing performance and is suitable as a grouting material for cracks in soil sites.
A diamond radiation detector with a length × width × height of 4.5 mm×4.5 mm×500 μm was designed,whose performance was optimized by forming Schottky on the diamond/Al surface,and its electrical characteristics(dark current,charge collection rate)and detection characteristics(energy resolu-tion)were tested.The results showed that the best charge collection rate was 96.9％.The dark current increased with the increase of the external bias,and was less than 0.1 nA within 100 V.The energy resolu-tion was the best when the bias voltage was 380 V,reaching 2.82％.It could be seen that the Schottky formed by the diamond/Al plane not only reduced the dark current,but also greatly improved the energy resolution of the diamond radiation detector.
To clarify the expression pattern of ornithine decarboxylase-1(ODC1)gene in species at dif-ferent altitudes and the molecular mechanism of adaptation to high altitude hypoxia in Phrynocephalus erythrurus,the gene structure,expression level,selection pressure,physicochemical properties and struc-ture of ODC1 gene in P.erythrurus were studied by combining genomics,transcriptomics,molecular evo-lution analysis and computational biology.The expression level of ODC1 gene in the four organs of P.erythrurus was about 2.25,1.14,2.51 and 4.82 times of that of P.przewalskii,and the expression levels in the liver,brain and heart tissues were significantly higher than those in the P.przewalskii.The ODC1 pro-tein grand average ofhydropathicity and instability index ofP.erythrurus was-0.122 and 46.51,respec-tively,which were more hydrophilic and stable than P.przewalskii.222Gly→Ala(potential positive selection site)and 228Ser→Asn located at the β/α barrel domain were two mutation sites of ODC1 protein in P.erythrurus,which rendered this domain more compact;the protein active center volume increased from 0.734 3 nm3(in P.przewalskii)to 0.744 8 nm3(in P.erythrurus),and the hydrophilicity of the active center increased.The 446Ile→Met amino acid mutation in the β-lamella domain resulted in the replacement of the random coil in this region by the α-helix.The significant up-regulation of ODC1 gene expression in P.erythrurus and the enhanced protein structure stability caused by amino acid mutation were both conducive to the protein accumulation to a higher concentration.The increased volume of ODC1 protein's active center in P.erythrurus caused by amino acid mutation had some effect on improv-ing the catalysis of ODC1.The up-regulation of ODC1 gene expression in P.erythrurus and changes in the physicochemical properties and structure of ODC1 were possibly one of strategies for adapting to the special environment characterized by high altitude hypoxia.The high expression of ODC1 gene and the change in the protein structure in the P.erythrurus might play an important role in the repair of tissue damage caused by hypoxia and the relief of pulmonary hypertension by improving the biosynthesis of polyamines.
SRS-150 dynamic ring shear apparatus was used to remould loess in an area in Tongwei,Gansu Province and to carry out an indoor ring shear test.The effects of salt content,fiber length and content on the shear strength of polypropylene fiber reinforced soil were analyzed,and the microscopic mechanism analyzed by scanning electron microscopy test.The shear strength of reinforced soil decreased first and then increased with the increase in salt content,and the limit value of salt content was about 6％;when the fiber content was 0.2％,0.4％and 0.6％,the peak strength of the reinforced soil was obviously im-proved,but the residual strength was not affected significantly;the longer the fiber length,the greater the cohesion of reinforced soil was.When the fiber length increased to more than 9 mm,the cohesion de-creased or slowed down;when the fiber content was lower than 0.4％,the internal friction angle of the re-inforced soil was little affected by the change in the fiber length.When the fiber content was higher than 0.4％,the longer the fiber length,the smaller the internal friction angle.The increase of salt content would reduce the thickness of the double electron layer of soil particles and increase the cohesive force between soil particles,so that more and more particle aggregates would be formed in the soil,and ulti-mately the shear strength of reinforced soil would change.The test showed that there was a limit value for the influence of salt content and fiber condition on the shear strength of reinforced soil.These control-lable factors can have a great influence on the reinforcement and protection of a fiber reinforced loess slope.In practical engineering application,the limit value in the test can be adjusted accordingly.
Aiming at the problems of modeling,high precision control and complex constraints of upper limb exoskeleton system with complex dynamic characteristics,a method improved multivariable con-straint generalized predictive control,based on T-S fuzzy system was proposed.The interval type 2 possi-bility C-means clustering algorithm was propounded to obtain the sample membership matrix needed in the process of data modeling,and the mathematical model of upper limb exoskeleton was established.For the complex constraint problem of the system,a constraint simplification method was put forward,which transformed the complex constraint of the system into the constraint on the parameter matrix and simpli-fies the constraint.A weighted basis function method was presented to introduce the basis function idea into the predictive control,and the upper limb exoskeleton predictive controller was derived.Simulation results verified the superiority and effectiveness of the proposed method.
This paper corrected the carbon emission coefficients of different land types in the Xining met-ropolitan area,and used five phases of Landsat image data from 2000,2005,2010,2015 and 2020 to mea-sure the carbon emissions of land use in the area.Eight indicators representing urban land use morpholog-ical changes,including the largest patch index,were selected,and the spatial lag model and spatial error model were used to analyze the impact of urban morphological indicators on carbon emissions.The research results showed that,compared with the situation of big cities in the east of China from 2000-2020,the intensity and total area of construction land in the Xining metropolitan area were smaller,and the growth rate of carbon emissions steady and slow.Construction land,which accounted for only 2.67％of the area,was an important source of carbon emissions from land use.Compared with citiesin plain areas,carbon emissions from land use in the Xining metropolitan area had obvious directions,and the expan-sion directions were mainly northwest,southeast and straight north.Except for the central area,the car-bon emissions from land use appeared as stars or irregular clusters in space.Changes in cultivated land had no significant impact on carbon emissions,while changes in the area and shape of construction land had a significant impact on carbon emissions in metropolitan areas.Construction land with a high inter-nal connectivity,fragmentation and complex shapes had higher carbon emissions.Irregular construction sites and clustering of dominant internal building types also led to an increase in regional carbon emis-sions,and the compactness of construction sites had a dampening effect on the growth of carbon emis-sions.Then we revealed the impact mechanism of land use forms on carbon emissions and finally gave suggestions and countermeasures for the Xining metropolitan area.
Five provincial capital cities in Northwest China were used as the study area,and the air quality monitoring and meteorological data from 2015-01-01 to 2020-07-21 used to construct a multiple stepwise regression(MSR),random forest(RF)and support vector machine(SVM)three air pollution forecasting models,with the mean absolute error,root mean square error and fit index(IA)as the evaluation indica-tors,so as to compare and analyze the model simulation accuracy.The results showed that,in the con-struction of air pollution forecasting models for the five cities,the RF importance assessment method was more suitable for screening forecasting factors than the Spearman correlation coefficient method.The or-der from strong to weak was MSR＞RF＞SVM,the forecast results of the three models all IA＞0.8,and the correlation between the forecast value and the actual observation value was high.
Based on a summary of the commonly used 3D geological modeling and groundwater numeri-cal simulation software,we used groundwater modeling system on the Heitai terrace,a typical loess table-land irrigation area in Yongjing County,Gansu Province to build up a 3D geological model.A solids stratigraphic model was carried out,combining the internal hole,boundary elevation,digital elevation model and other basic information in the study area.The formation modeling data were combined with the hydrologic activities of the research area,and then a hydrologic conceptual model and mathematical model were established.The numerical calculation method of MODFLOW in the software was used to obtain a groundwater numerical model for the study area under the verification of the inversion informa-tion by electrical resistance tomography.The results showed that the 3D model had a good visibility and could display the distribution of strata in the study area.And the simulated groundwater elevation in the middle of the area had a good correlation with the inversion result.
The synergistic effects of El Niño-Southern oscillation(ENSO)and Indian Ocean dipole(IOD)on the subtropical westerly jet(SWJ)in autumn and their mechanisms were investigated by using the National Centers for Environmental Prediction and National Center for Atmospheric Research of American reanalysis data during 1979-2020,Niño3.4,IOD and SWJ index.The correlation coefficients of SWJ strength index with the Niño3.4 and IOD indices were-0.32 and-0.31 respectively,and the correlation coefficients of the jet axis index with the Niño3.4 and IOD indices were-0.75 and-0.34 respectively,i.e.when the ENSO and IOD were in a positive(negative)phase,SWJ weakened(strengthened)and the jet was located to the south(north).ENSO and IOD events had a synergistic effect on SWJ,as shown by the simultaneous occurrence of ENSO and IOD warm or cold phases,when the ENSO and IOD warm or cold events together had a greater effect on SWJ than when they acted separately,i.e.when ENSO and IOD positive(negative)phases occurred together,SWJ weakened(strengthened)to a greater extent.Further research proved that ENSO and IOD events could influence SWJ through atmospheric instability and the Hadley circulation.When ENSO and IOD positive events occurred together,there was a negative spatial leveling of upper tropospheric temperatures,a negative difference in the longitudinal temperature gradient over 200-500 hPa,and a slower increase in latitudinal winds with increasing height.The Had-ley circulation also varied between ENSO and IOD events.Under La Nina and IOD negative phase,the upward branch of the Hadley circulation was stronger and in a higher position than when ENSO and IOD were in a positive phase,carrying more of the Earth's angular momentum into SWJ rapids,and causing the jet to strengthen.
For large-scale imaging scenarios,we designed the first time a new inversion model and com-bined the muon tomography technique based on flux attenuation with the limited memory Broyden-Fletcher-Goldfarb-Shanno method for intelligent computing.It eliminates the need for matrix pseudo in-verses and storing Hessian matrices,and reduces the computational complexity and the occupation of memory resources.When the density interval of the measured object was known,using reasonable upper and lower limit constraints and reference models improve the accuracy of the results.For inversion prob-lems with upper and lower limits constraints,an interior penalty function was designed to transform con-strained optimization problems into unconstrained ones.The simulation results showed that the proposed inversion algorithm has satisfactory performance in large-scale inversion problems,and the interior penal-ty function can also play a good constraint role.
The China-Pakistan Economic Corridor(CPEC)is a key passage connecting China with South Asia and West Asia.Most parts of CPEC are in areas of the Tibetan Plateau and Pamir Plateau and,with unique and dynamic geomorphology and geo-environment backgrounds,a mass of landslides,debris flow,and glacier surging-related or-induced geohazards,presenting challenges to the normal construc-tion and operation of CPEC,and also bringing disasters and loss for the local society and human life.The study systematically summarized the study progress in the geohazard identification and inventory,hazard assessment,and geohazard prevention and mitigation.Based on that,the shortages of recent studies were pointed out.The study on geohazard development background has been relatively unsubstantial,and early identification of geohazards needed to be further strengthened,the characteristics and mechanism of geo-hazards have not been clearly investigated,the methodology of hazard assessment needed to be advanced,and the comprehensive prevention and control of geological disasters needed to be further enhanced.According suggestions were proposed.The study proposed the prospects in three fields including carry-ing out an environmental geology census and geo-hazard detailed survey to establish a complete database on geological disasters;promoting the establishment of an air-space-ground joint monitoring and identifi-cation technology system suitable for the geohazards study in CPEC,promoting satellite data sharing;car-rying out systematic and comprehensive research on geological disaster prevention and control,risk iden-tification,disaster reduction and post-disaster recovery in CPEC.
The spatial and temporal distribution characteristics and trends of cloud water resources and precipitation in non-monsoon and monsoon regions of China were compared and analysed with monthly mean cloud data from the International Satellite Cloud Climatology Project and monthly precipitation data from the Global Precipitation Climatology Project from 2000-2016,and the European Centre for Medium-range Weather Forecasts ERA-5 water vapour transport data during 2000-2016.Transport flux reanalysis data from 2000-2016 were used to analyze the interannual variation characteristics of water va-por transport paths and total column water vapor in the above regions.The results indicated that,in terms of spatial distribution,cloud water content and precipitation in China basically showed the characteristics of a higher average value in Northern and a lower in Southern China,with high value areas often distrib-uted along high mountain ranges.In terms of intra-annual variability,total cloudiness,low cloudiness,cloud-water path and precipitation all manifested obvious seasonal variations,with the exception of low cloudiness,which had a significant peak in June.In terms of interannual variability,the total cloud amount in the non-monsoon region showed a decreasing trend;and that in the monsoon region showed an increasing trend,with an average increase of 5％per decade;precipitation and cloud-water paths in both regions showed an increasing trend,with an average increase of 0.3 g/(m2·a)and 0.01 mm/d in the monsoon region;the average increase in the non-monsoon region was 0.22 g/(m2·a)and 0.009 mm/d,while low cloud levels showed a decreasing trend,with an average decrease of 0.86％per decade in the non-monsoon region and 0.46％in the monsoon region.It was found that there had been a significant increase in water vapour flux to the inland via the Northwest and Northeast in recent years,constituting the main reason for the recent increase in precipitation in China.
With the precipitation data of an automatic meteorological observation station in Qianxinan Prefecture of Guizhou Province in May 2018,radar data of Xingyi Station and the CMORPH satellite pre-cipitation products,an optimal interpolation method was used to carry out merging experiments on three types of precipitation data.In this experiment,four precipitation merging schemes were designed,and the regional accuracy of the merging precipitation data tested respectively.The results indicated that satellite-ground merging precipitation,compared to that before the correlation coefficient,decreased from 66.19％to 79.68％,the deviation decreased from-0.544 to-0.247 mm/h and the root mean square error de-creased from 2.944 to 1.353 mm/h after the probability density matching method was adopted.The ac-curacy of the merging precipitation was higher after the probability density matching method was ad-opted.When only two precipitation data sources were input to the merging precipitation model,the one with a higher accuracy had a greater impact on the accuracy of the merging precipitation.The results of satellite radar ground merging precipitation evaluation showed that the correlation coefficient reached 81.32％,the deviation and root mean square error were-0.219 and 1.037 mm/h respectively,and the accuracy higher than other merging precipitation schemes,meaning that the accuracy of area precipita-tion could be significantly improved by integrating more effective precipitation data sources.
In order to study the formation and development process of sand dunes in the Suoyang City site,SBAS-InSAR technology was used to monitor the site area.The sentinel-1A data of ascending 42 and descending 41 covering the research area from October 2014 to August 2021 were selected for pro-cessing.The deformation rate field in the radar line of sight and the vertical deformation rate field were obtained after projection transformation,and the accuracy of InSAR monitoring results verified.Com-bined with the meteorological data and the characteristics of the shape and preservation status of Suoyang City,it was found that,in the Suoyang City site area,the accumulation rate gradually increased from west to east.The sand deposition rate on both sides of the south section of the west wall and the outside of the east wall was the fastest,and the maximum sand deposition rate was 1.24 mm/a.The outside of the west wall was mainly eroded,with the maximum erosion rate being-0.89 mm/a.The east wind and west wind accounted for 67.92％and 28.18％of the sand-moving wind,respectively,which was consistent with the sand accumulation direction monitored by InSAR.
Using the global sea surface temperature(SST)data and reanalysis data from 1979 to 2021,the variability of the boreal winter Hadley circulation(HC)and its relationship with tropical SST anomalies were discussed,and its impact on contemporaneous precipitation and temperature in China further stud-ied.The results indicated that the EOF1 mode of HC(46.2％)was an asymmetric mode with the main body of the ascending branch located around 10°S in the northern hemisphere,including interdecadal and interannual variability,the former being closely related to the Indian Ocean(20°S-20°N,50°-90°E)SST with the non-uniform north-south warming trend(more in the southern hemisphere than in the northern hemisphere);interannual variability was related to the Indian Ocean(10°S-10°N,50°-90° E)where the anomalous SST meridional gradient along the positive direction(and the gradient changing from positive to negative)being zero occurred in the southern hemisphere under the El Niño event.The EOF2 mode(16.7％)was about the equatorial symmetric mode and only reflected the interannual variability.This mode was associated with the anomalous symmetric meridional thermodynamic structure of the tropical eastern Pacific(180°E-90°W)under the El Niño event.The two modes were roughly positively correlat-ed with contemporaneous precipitation and temperature in China.Under the influence of EOF,(EOF2)mode,there was more precipitation in the southeastern coastal areas of China(southeast of the southern region),relating to the ascending branch of HC in the region of 110°-120°E.In the EOF,mode,there was a positive temperature anomaly in the northwest-central region of China,which was closely related to the adiabatic heating effect of the subsidence movement.Under the EOF2 mode,the temperature in China was also a positive anomaly,but the temperature anomaly was not significant.
在祁连山及周边地区采集表层沉积物样品444份,分析表层沉积物磁化率的空间分布特征,结合祁连山及周边地区地层沉积物磁化率的研究成果,探讨沉积物磁化率的指示意义.结果表明,表层沉积物磁化率与经度相关性较高,以97°～98°E为界,东侧磁化率主要受控于亚洲季风;西侧受控于西风环流,磁化率受风力或者风沙输送影响,与物源有关.地层沉积物磁化率在不同环流系统中意义存在差异,亚洲夏季风控制区沉积物磁化率与气候湿润程度呈正相关,西风模态核心区反之,过渡区沉积物磁化率对气候的响应更加复杂.
尝试性地建立梯形土体的土压力理论(包括主、被动土压力),挡土墙被简化为光滑直立型.通过算例的数值分析发现,梯形土体的土压力理论给出的主、被动土压力均小于等于经典土压力理论Rankine公式和Coulomb公式的主、被动土压力,其差值在地表附近为0,当深度有一定增加时会出现,并随深度的增加而变大,且该差值在被动土压力中表现得更明显.结果表明,与新建立的关于梯形土体的土压力理论相比,Rankine土压力理论和Coulomb土压力理论会在一定程度上高估梯形土体的主、被动土压力.
探究微波功率和样品负载量对多孔硅酸钙微波干燥动力学和特性的影响.结果表明,Midilli模型是微波干燥多孔硅酸钙的最佳模型.多孔硅酸钙水分有效扩散系数(Deff)随着样品负载量的降低和微波功率的增加呈上升趋势,样品负载量为4～30 g时,对应的Deff=4.265×10-9～1.967×10-9 m2/s,微波功率为100～350 W时,对应的Deff=3.222×10-9～25.224×10-9 m2/s,微波功率密度相同时,微波功率愈大Deff越高.增加多孔硅酸钙负载量和增加微波功率都能提升微波干燥效率,样品负载量为4～30 g时,对应的微波干燥效率为6.04％～21.52％,微波功率为100～350 W,对应的干燥效率为11.57％～28.69％.通过扫描电子显微镜和傅立叶变换红外光谱对材料进行表征,微波干燥后的多孔硅酸钙与传统方法干燥后的相比,脱除了部分化学结合水,颗粒的团聚减少,颗粒分散性明显提高.
研究青蒿浸膏的亚慢性毒性反应及其靶器官.设3.0、3.9、5.1、6.8 g/kg4个给药剂量组和一个空白对照组,空白组为大豆油;经口给Sprague-Dawley大鼠灌服1次/d,连续给药28 d;分别于相应时间点对大鼠行为、组织病理学变化、血液生理生化指标等进行检测.结果表明,给药5 d后,5.1和6.8 g/kg组雄性大鼠均出现听力减弱的现象.3.9、5.1和6.8 g/kg组雄性大鼠白细胞和淋巴细胞数量均高于对照组;3.0、3.9、5.1和6.8 g/kg组雄性大鼠红细胞少于对照组;4个剂量组雌、雄大鼠血清肌酐水平均少于对照组.5.1、6.8g/kg组雌、雄大鼠肝脏脏器系数均明显增大.解剖和病理学结果表明,高剂量组的肝脏、中央静脉周围结构和小肠的结构有病变.高剂量青蒿浸膏连续用药28 d对大鼠神经系统、血细胞和肝脏造成毒性损伤,3.0 g/kg为安全剂量.
