郑州工程技术学院（Zhengzhou University of Technology）是一所河南省属公办全日制本科普通高等学校，是国家建设类技能型紧缺人才培养试点高校。 学院创建于1980年的郑州大学、河南医学院分校；1981年，更名为郑州走读大学；1985年，更名为中州大学；2009年，郑州艺术学校并入学校；2014年，郑州广播电视大学并入学校；2016年3月，升格为郑州工程技术学院。 截至2020年4月，学院共有英才校区、金河校区、航海路校区、龙子湖校区四个校区，占地面积1484.84亩，建筑面积53.15万平方米，教学仪器设备总值2.41亿元，学校图书馆馆藏纸介质图书160余万册；有教职工1143人，专任教师788人，在校学生12866人；开设19个二级学院、29个本科专业、40个专科专业。
Objectives This study aims to elucidate the correlation mechanism between the bleeding charac-teristics of backfill slurry and mesoscopic water migration,and to reveal the influence of macro-meso struc-tural evolution on the bleeding process.Methods An orthogonal experimental design was conducted to test fluidity,bleeding rate,and settling rate.Range analysis and efficacy coefficient calculations were com-bined with a Matlab-based 3D visualization multi-factor coupling model to determine the optimal mix ratio.Nuclear magnetic resonance(NMR)was used to analyze the mesoscopic water migration characteristics of the optimal slurry at standing times of 5,30,60,90,120,and 180 minutes.Results The optimal mix ra-tio was identified as a cement-tailings ratio of 1:8,a mass concentration of 74%,and a water-reducer dos-age of 1%.The significance order of factors affecting bleeding rate was:mass concentration>cement-tailings ratio>water-reducer dosage.NMR results indicated that in high-solid-concentration backfill slurry,adsorbed water was the dominant form;pore water acted as a dynamic transitional state,with fluctuating peak areas reflecting the balance between adsorbed water release and interfacial re-adsorption;and free wa-ter increased with prolonged standing time.Conclusions The bleeding process of backfill slurry can be di-vided into four distinct stages:induction period,acceleration period,constant period,and stabilization pe-riod.Water migration follows the pathway of adsorbed water→pore water→free water.The migration rate is slowest during the induction period,peaks in the acceleration period as adsorbed water rapidly converts to free water,remains rapid in the constant period,and becomes restrained in the stabilization period,result-ing in a steady bleeding state.This study provides insight into the mechanism linking bleeding characteris-tics to mesoscopic water migration and provides a theoretical basis for optimizing backfill parameters in deep mining.
The nearest neighbor query and its extended variants are crucial topics in the field of spatial databases and have been widely applied in geographic information systems,pattern recognition,decision support,urban planning,and many other fields.In recent years,numerous algorithms for nearest neighbor queries and their variants have been proposed,prompting a comprehensive analysis of existing work in this area.Regarding nearest neighbor query index structures,this paper introduces the research progress of current spatial index structures in detail,including grid-based spatial index structures,tree-based spatial index structures,and hybrid spatial index structures,analyzing the advantages and disadvantages of each.For variant query algorithms of nearest neighbor queries,the focus is on analyzing several types of nearest neighbor variant queries:reverse nearest neighbor query algorithms,continuous nearest neighbor query algorithms,nearest pair query algorithms,obstacle nearest neighbor query algorithms,and nearest neighbor-based spatial Skyline query algorithms.For each variant,the characteristics,research status,and core technologies of the algorithms are thoroughly analyzed,and the advantages,disadvantages,and application scopes of the variant algorithms are summarized.Finally,it clarifies the current challenges faced in research,such as the continuously increasing volume of spatial data,the high dimensionality of spatial data,and the diversity of data query demands.It also looks forward to future development trends.
Seasonal temperature changes in the seasonal frozen areas have a significant impact on the engineering application performance of the underground pipe galleries.To study the effects of ambient temperature in the seasonal frozen areas on the temperature field and mechanical behaviors of the underground pipe galleries,the change laws of temperature field and earth pressure of the underground pipeline galleries under seasonal ambient temperature are studied by conducting the ABAQUS finite element numerical simulation.The numerical analysis results indicate that the occurent moment of the maximum freezing depth of the vertical section inside the pipe gallery is lagged behind that of the lowest ambient temperature.During the process of heating and cooling,the temperature fields inside the upper and nearby areas of the pipe gallery successively exhibit the special phenomena such as"cold core zone"and"hot core zone".These phenomena gradually disappear with the continuous effects of heating and cooling.During the cooling and heating processes,the earth pressure on the roof of the pipe gallery shows an increasing and decreasing tendency.After the influences of seasonal temperature,the earth pressure on the roof is significantly greater than that at the initial state.
The extraction technology of flavonoid from polygonatum kingianum was studied by ultrasonic-assisted deep eutectic solvents method,and its biological activity was preliminarily studied. On the basis of single factor experiments of choline chloride-lactic acid molar ratio,ultrasonic extraction temperature,ultrasonic extraction time,choline chloride-lactic acid water content and material liquid ratio,the response surface optimization experiment was conducted to select ultrasonic extraction temperature,ultrasonic extraction time and choline chloride-lactic acid water content for optimal extraction process. Antioxidant and hypoglycemic tests were selected to evaluate biological activities. The results showed that the optimum extraction conditions of flavonoid from Polygonatum kingianum was as follows :choline chloride-lactic acid molar ratio of 1∶2,ultrasonic extraction temperature of 45 ℃,ultrasonic extraction time of 40 min,choline chloride-lactic acid water content of 20% and material liquid ratio of 1∶20 g/m L. Under these conditions,the extraction rate of flavonoid from Polygonatum kingianum was 17.13%±0.25%. Flavonoid from Polygonatum kingianum had strong ability to scavenge DPPH free radicals and ABTS free radicals and to inhibit α-glucosidase and α-amylase activity. The EC50 values of its activity were 2.11,1.63,1.70 and 2.69 mg/m L,respectively. The results showed that flavonoid from Polygonatum kingianum had certain antioxidation and hypoglycemic effects. Flavonoid from Polygonatum kingianum had strong bioactivity and could be used as a raw material in the food industry.
