Predictive Ability of Hypertriglyceridemic Waist,Hypertriglyceridemic Waist-to-Height Ratio,and Waist-to-Hip Ratio for Cardiometabolic Risk Factors Clustering Screening among Chinese Children and Adolescents

Objective Hypertriglyceridemic waist(HW),hypertriglyceridemic waist-to-height ratio(HWHtR),and waist-to-hip ratio(WHR)have been shown to be indicators of cardiometabolic risk factors.However,it is not clear which indicator is more suitable for children and adolescents.We aimed to investigate the relationship between HW,HWHtR,WHR,and cardiovascular risk factors clustering to determine the best screening tools for cardiometabolic risk in children and adolescents.Methods This was a national cross-sectional study.Anthropometric and biochemical variables were assessed in approximately 70,000 participants aged 6–18 years from seven provinces in China.Demographics,physical activity,dietary intake,and family history of chronic diseases were obtained through questionnaires.ANOVA,χ2 and logistic regression analysis was conducted.Results A significant sex difference was observed for HWHtR and WHR,but not for HW phenotype.The risk of cardiometabolic health risk factor clustering with HW phenotype or the HWHtR phenotype was significantly higher than that with the non-HW or non-HWHtR phenotypes among children and adolescents(HW:OR=12.22,95%CI:9.54-15.67;HWHtR:OR=9.70,95%CI:6.93-13.58).Compared with the HW and HWHtR phenotypes,the association between risk of cardiometabolic health risk factors(CHRF)clustering and high WHR was much weaker and not significant(WHR:OR=1.14,95%CI:0.97-1.34).Conclusion Compared with HWHtR and WHR,the HW phenotype is a more convenient indicator with higher applicability to screen children and adolescents for cardiovascular risk factors.

An Experimental and Numerical Thermal Flow Analysis in a Solar Air Collector with Different Delta Wing Height Ratios

This study conducts both numerical and empirical assessments of thermal transfer and fluid flow characteristics in a Solar Air Collector(SAC)using a Delta Wing Vortex Generator(DWVG),and the effects of different height ratios(Rh=0.6,0.8,1,1.2 and 1.4)in delta wing vortex generators,which were not considered in the earlier studies,are investigated.Energy and exergy analyses are performed to gain maximum efficiency.The Reynolds number based on the outlet velocity and hydraulic diameter falls between 4400 and 22000,corresponding to the volume flow rate of 5.21–26.07 m^(3)/h.It is observed that the delta wing vortex generators with a higher height ratio yield maximum heat transfer enhancement and overall enhancement ratio.The empirical and numerical findings demonstrate that the exergy and thermal efficiencies decline in a specific range.TheNusselt number,pressure drop,energy,and exergy efficiencies enhance with rising Reynolds number,although the friction coefficient diminishes.The maximum heat transfer enhancement is 57%.According to the evaluation of exergy efficiency,the greatest efficiency of 31.2%is obtained at Rh=1.4 and Reynolds number 22000.

Dynamics and Wheel's Slip Ratio of a Wheel-legged Robot in Wheeled Motion Considering the Change of Height

The existing research on dynamics and slip ratio of wheeled mobile robot （WMR） are derived without considering the effect of height, and the existing models can not be used to analyze the dynamics performance of the robot with variable height while moving such as NOROS- Ⅱ. The existing method of dynamics modeling is improved by adding the constraint equation between perpendicular displacement of body and horizontal displacement of wheel into the constraint conditions. The dynamic model of NOROS- Ⅱ in wheel motion is built by the Lagrange method under nonholonomic constraints. The inverse dynamics is calculated in three different paths based on this model, and the results demonstrate that torques of hip pitching joints are inversely proportional to the height of robot. The relative error of calculated torques is less than 2% compared with that of ADAMS simulation, by which the validity of dynamic model is verified, Moreover, the relative horizontal motion between fore/hind wheels and body is produced when the height is changed, and thus the accurate slip ratio can not be obtained by the traditional equation. The improved slip ratio equations with the parameter of the vertical velocity of body are introduced for fore wheels and hind wheels respectively. Numerical simulations of slip ratios are conducted to reveal the effect of varied height on slip ratios of different wheels. The result shows that the slip ratios of fore/hind wheels become larger/smaller respectively as the height increases, and as the height is reduced, the reverse applies. The proposed research of dynamic model and slip ratio based on the robot height provides the effective method to analyze the dynamics of WMRs with varying height.

Stress-strain-acoustic responses in failure process of coal rock with different height to diameter ratios under uniaxial compression

Residual coal pillars play an important role in mining the adjacent coal seam safely,managing the gobs and maintaining the stability of abandoned coal mines.The height to diameter ratio(H/D)affects the stability of residual coal pillars.In this study,uniaxial compressive tests of coal specimens with five H/D(2.0,1.5,1.0,0.8 and 0.6)were performed,and the stress,strain and acoustic emission(AE)were monitored.Results show that the uniaxial compressive strength(UCS)and peak strain increase with H/D decreasing.An empirical equation is proposed to calculate the UCS based on the H/D.The AE activities during coal failure process can be separated into four periods.The span of quiet period and rapid decline period shorten with H/D decreasing.The smaller the H/D is,the more complicated the failure characteristics of coal will be.The failure form of coal with H/D of 2.0,1.5,and 1.0 is primarily shear failure,while splitting failure along the axial direction is the mainly mode when H/D is 0.8 or 0.6.The initiation,expansion,aggregation and connection of micro-cracks can be reflected by the real-time spatial evolution of AE event points.

Effects of Different Sowing Times on Plant Height, Leaf Stem Ratio and DW/FW Ratio of Forage Sorghum in Autumn Idle Land

The aim was to explore the linear regression prediction models between sowing time and plant height, leaf stem ratio and DW/FW ratio of forage sorghum in autumn idle land. [Method] The relationships between sowing time and plant height, leaf stem ratio and DW/FW ratio of forage sorghum were simulated and compared by employing field plot experiment and linear regression analysis. [Result] The sowing time had a great impact on plant height, leaf stem ratio and DW/FW ratio of forage sorghum in autumn idle land. With the delay of sowing time, the plant height and DW/FW ratio of forage sorghum decreased, while the leaf stem ratio increased. The regression models between sowing time and plant height, leaf stem ratio and DW/FW ratio of forage sorghum were established： plant height and sowing time, yheight = 234.725- 5.005X; leaf stem ratio and sowing time,ylcaf= 0.096 ＋ 0,019x; DW/FW ratio and sowing time, ydry= 0.305-0.002X. From July 23rd to August 30th, the plant height of forage sorghum was reduced by 5.005 cm, the leaf stem ratio was increased by 0.019 and the DW/FW ratio was reduced by 0.002 in average when hhe sowing time was delayed by one day. [Conclusion] This study provides a theoretical support for the production of forage sorghum in autumn idle land.

Research on the squeeze cast technology of the castings with large ratio of height to thickness

The squeeze cast technology is only applicable, at present, to the castings with a ratio of height to thickness less than 3.5. Researching the squeeze cast technology for castings with a large ratio of height to thickness will broaden the applicable range of the advanced casting technology. This paper describes a study of the temperature distribution during solidification for castings with a ratio of height to thickness of 7 by the methods of experiment and computer simulation. The shrinkage porosity distribution in the castings and the mechanical properties of the castings were also researched. The experimental and simulated results show that increasing squeeze force, or enhancing mold temperature, cannot reduce the shrinkage porosities in the castings. When castings solidify in a sequential manner and the squeeze force effectively acts on the surface of the liquid metal, the shrinkage porosities in the castings are eliminated and mechanical properties are clearly improved.

Rational cutting height for large cutting height fully mechanized top-coal caving

Large cutting height fully mechanized top-coal caving is a new mining method that improves recovery ratio and single-pass production. It also allows safe and efficient mining. A rational cutting height is one key parameter of this technique. Numerical simulation and a granular-media model experiment were used to analyze the effect of cutting height on the rock pressure of a fully mechanized top-coal caving work face. The recovery ratio was also studied. As the cutting height increases the top-coal thickness is reduced. Changing the ratio of cutting to drawing height intensifies the face pressure and the top-coal shattering. A maximum cutting height exists under a given set of conditions due to issues with surrounding rock-mass control. An increase in cutting height makes the top-coal cave better and the recovery ratio when drawing top-coal is then improved. A method of adjusting the face rock pressure is presented. Changing the cutting to drawing height ratio is the technique used to control face rock pressure. The recovery ratio when cutting coal exceeds that when caving top-coal so the face recovery ratio may be improved by over sizing the cutting height and increasing the top-coal drawing ratio. An optimum ratio of cutting to drawing height exists that maximizes the face recovery ratio. A rational cutting height is determined by comprehensively considering the surrounding rock-mass control and the recovery ratio. At the same time increasing the cutting height can improve single pass mining during fully mechanized top-coal caving.

Change of the mode of failure by interface friction and width-to-height ratio of coal specimens

Bumps in coal mines have been recognized as a major hazard for many years. These sudden and violent failures around mine openings have compromised safety, ventilation and access to mine workings.Previous studies showed that the violence of coal specimen failure depends on both the interface friction and width-to-height（W/H） ratio of coal specimen. The mode of failure for a uniaxially loaded coal specimen or a coal pillar is a combination of both shear failure along the interface and compressive failure in the coal. The shear failure along the interface triggered the compressive failure in coal. The compressive failure of a coal specimen or a coal pillar can be controlled by changing its W/H ratio. As the W/H ratio increases, the ultimate strength increases. Hence, with a proper combination of interface friction and the W/H ratio of pillar or coal specimen, the mode of failure will change from sudden violent failure which is brittle failure to non-violent failure which is ductile failure. The main objective of this paper is to determine at what W/H ratio and interface friction the mode of failure changes from violent to non-violent. In this research, coal specimens of W/H ratio ranging from 1 to 10 were uniaxially tested under two interface frictions of 0.1 and 0.25, and the results are presented and discussed.

A new strategy for ionospheric remote sensing using the 130.4/135.6 nm airglow intensity ratios

We demonstrate here that global-scale determination of a key ionospheric parameter,the peak height of the F_(2)region(h_(m)F_(2)),can be obtained by making a simple ratio measurement of the atomic oxygen 130.4 and 135.6 nm emissions in the far-ultraviolet nightglow with a nadir-viewing system such as a pair of photometers suitable for flight on a CubeSat.We further demonstrate that measurements from an altitude that is within the typical range of nighttime h_(m)F_(2)250−450 km can provide the ratios that are needed for retrieval of the h_(m)F_(2).Our study is conducted mostly through numerical simulations by using radiative transfer models of the two emissions coupled with empirical models of the atmosphere and ionosphere.Modeling results show that the relationship between the h_(m)F_(2)and the intensity ratio is sensitive to the altitude from which the emissions are observed,primarily because of the distinctly different degrees of resonant scattering of the two emissions in the atmosphere.A roughly quadratic relationship can be established for observations from an orbit of~400 km,which enables h_(m)F_(2)retrieval.Parametric analysis indicates that the relationship can be affected by the ambient atmospheric conditions through resonant scattering and O2 absorption.For typical nighttime conditions with h_(m)F_(2)250−450 km,retrieval of the h_(m)F_(2)from synthetic observations shows that the typical errors are only a few kilometers(up to~20 km),depending on the accuracy of the ambient conditions predicted by the empirical models.Our findings pave the way for use of the 130.4/135.6 nm intensity ratios for global-scale monitoring of the nighttime ionosphere at mid to low latitudes.

Finite element analysis on the collapse of infill walls with holes and different length-to-height ratios

Wenchuan earthquake damage survey displayed the major structures of buildings suffered only small damages,but it was common that infill walls suffered heavy damages or even collapse. To study the failure forms and collapse mechanism of infill walls in an earthquake,the influence of opening or length-to-height ratio on shake-resisting capability of filling walls was analyzed,and measures to improve the anti-collapse ability of infill walls were put forwaed. The numerical simulations on collapse process in earthquake were carried out by using ABAQUS software. We used 5 single story and single span models. It is revealed that the rigidity and compressive capacity of infill walls are reduced because of the infill walls with holes and the increases of length-to-height ratios. Adding constructional columns and horizontal beams can ensure structural integrity and improve the anti-collapse ability of the wall.

Analysis of Ankle-Brachial Index, Waist-Hip Ratio, Ejection-Fraction, Obesity, Smoking, Alcohol Habits, Diabetes and Hypertension as Independent Predictors of Complexity and Severity of Coronary Artery Disease

Background: The present study was conducted to examine the association between various coronary risk factors and clinical parameters, with special emphasis on ankle-brachial index, in predicting the severity and complexity of coronary artery disease. Methods: Patients diagnosed with coronary artery disease at our hospital between September-2012 and December-2014 were examined in this study. Selected patients were screened for cardiovascular risk factors including diabetes, hypertension, smoking, and alcohol habits as well as for clinical parameters including body-mass index, waist-hip ratio, ankle-brachial index, and ejection fraction. All patients underwent coronary angiography and were evaluated for severity of coronary artery disease (based on number of vessels involved) and complexity of coronary angiographic lesions (measured by computer-assisted Syntax score calculator). The collected data were analyzed to determine the role of cardiovascular risk factors and clinical parameters as predictors of complexity and severity of coronary artery disease. Results: A total of 211 patients (mean age: 54.64 ± 9.9 years;81% males) with coronary artery disease were analyzed. Findings revealed that diabetes mellitus (p < 0.001), hypertension (p < 0.001), smoking habits (p = 0.036), and low ankle-brachial index (p < 0.001) were independent predictors of complex coronary artery disease as measured by Syntax score. Significant associations were also evident between severity of coronary artery disease and diabetes mellitus (p < 0.001), hypertension (p < 0.001), and ankle-brachial index (p < 0.001). Conversely, other cardiovascular risk factors including body-mass index, alcohol habits, wait-hip ratio, and ejection fraction did not exhibit significant associations with severity and complexity of coronary artery. Conclusions: The early diagnosis of coronary artery can be predicated by evaluating diabetes, hypertension, and smoking habits in patients presenting with acute coronary syndrome. In addition, ankle-brachial index can be used as an effective non-invasive bed-side tool, as an alternative to Syntax score, in predicting the severity and complexity of coronary artery disease.

老年高血压人群腰围身高比与新发脑梗死的关系

目的研究腰围身高比(WHtR)与老年人新发脑梗死的相关性。方法纳入开滦地区研究人群9096例老年高血压患者,以首次发生脑梗死为终点事件,采取前瞻性队列研究方法进行研究,依据观察对象WHtR值以0.05为间距等距分为四组,分别为G1组(WHtR<0.45)、G2组(0.45≤WHtR<0.50)、G3组(0.50≤WHtR<0.55)及G4组(WHtR≥0.55),用寿命表方法统计各人群的累积终点事件发生率,采用Cox比例风险分析方法,探讨WHtR在新发脑梗死中的作用。模型一为单一因子Cox比例风险分析模式,只考察WHtR对脑梗死发生风险的作用;在此基础上,模型二为校正性别、年龄、体重及血清超敏C反应蛋白、收缩压、血清甘油三酯、抽烟史、血清空腹血糖、饮酒情况、高密度脂蛋白胆固醇、舒张压、体育运动、低密度脂蛋白胆固醇、文化程度、服降压药史后观察WHtR对新发脑梗死的作用。结果随访时间为(9.3±2.7)年,期间共新发脑梗死848例。以G2组为对照,单因素Cox比例风险回归模型分析显示G1组、G3组和G4各组发生脑梗死的HR(95%CI)分别为1.00(0.67~1.50)、1.29(1.05~1.60)、1.36(1.12~1.66);多因素Cox比例风险回归模型分析显示G1组、G3组和G4各组发生脑梗死的HR(95%CI)分别为1.09(0.72~1.65)、1.24(0.99~1.54)、1.31(1.05~1.62)。结论老年高血压人群当0.45≤WHtR<0.50时脑卒中发病风险最低,WHtR≥0.55与新发脑梗死风险增加相关。

体重指数、腰臀比及胰岛素抵抗与绝经后子宫内膜息肉发病的相关性分析

目的探究体重指数(BMI)、腰臀比(WHR)及胰岛素抵抗(IR)与绝经后子宫内膜息肉(EP)发病的相关性。方法选取2021年10月至2023年1月资阳市人民医院收治的180例怀疑为绝经后EP患者作为研究对象。根据病理检查结果将其分为EP组(n=90)和非EP组(n=90)。比较两组的BMI、WHR、IR发生情况、性激素水平,分析BMI、WHR及IR与绝经后EP发病的关系。结果EP组的BMI、腰围、臀围、WHR均高于对照组(P<0.05);EP组空腹血糖(FBG)、空腹胰岛素(FIN)、稳态模型胰岛素抵抗指数(HOMA-IR)水平及IR发生率均高于非EP组(P<0.05);两组黄体生成素(LH)、卵泡刺激素(FSH)、雌二醇(E_(2))、孕酮(P)水平比较,差异无统计学意义(P>0.05);EP患者BMI、WHR与HOMA-IR均呈正相关(P<0.05);BMI、WHR、HOMA-IR是EP发生的独立危险因素。结论BMI、WHR、HOMA-IR与绝经后EP发生均具有相关性,临床需重视肥胖、胰岛素水平过高患者,定期进行妇科检查。

Multi-objective Optimization of a Two-Stage Helical Gearbox to Improve Efficiency and Reduce Height

The goal of this research is to look at multi-target optimization of a two-stage helical gearbox in order to determine the best key design elements for reducing gearbox height and enhancing gearbox efficiency.To do this,the method known as Taguchi and GRA(Grey Relation Analysis)were used in two stages to address the problem.The single-objective optimization problem was addressed first to close the gap between variable levels,and then the multi-objective optimization problem was solved to determine the best primary design variables.The first and second stage CWFWs(Coefficients of Wheel Face Width),ACS(Permissible Contact Stresses),and first stage gear ratio were also calculated.The study’s findings were utilized to identify the best values for five critical design aspects of a two-stage helical gearbox.

中心性肥胖对不孕女性体外受精-胚胎移植妊娠结局的影响

目的探讨中心性肥胖对不孕女性接受体外受精-胚胎移植后的妊娠结局的影响。方法回顾性选取2017年10月至2019年9月在温州医科大学附属第一医院生殖医学中心首次接受体外受精-胚胎移植的2801例不孕女性为研究对象。根据进入治疗周期时的BMI和腰臀比(WHR)分为正常BMI非中心性肥胖组1659例、正常BMI中心性肥胖组654例、肥胖非中心性肥胖组146例和肥胖中心性肥胖组342例,比较4组治疗过程中促性腺激素使用剂量、促排时间、获卵数、可用胚胎数及新鲜胚胎移植妊娠结局。采用多元线性回归分析中心性肥胖对促排周期获得可用胚胎数的影响,多因素logistic回归分析影响患者新鲜胚胎移植能否获得活产的相关因素。应用Kaplan-Meier生存曲线绘制各组单个取卵周期累积活产率。结果与正常BMI非中心性肥胖组相比,肥胖中心性肥胖组促性腺激素使用剂量增加,获卵数和可用胚胎数减少,新鲜胚胎移植后活产率下降,妊娠丢失率增加,单个取卵周期累积活产率下降,差异均有统计学意义(均P<0.05)。多元线性回归分析提示WHR≥0.85显著降低患者促排周期获得的可用胚胎数。不论BMI是否提示肥胖,WHR≥0.85的中心性肥胖女性,其单个取卵周期累积活产率较正常BMI非中心性肥胖组女性下降(均P<0.05)。多因素logistic回归分析发现腰围的增加会使新鲜胚胎移植后活产率降低(OR=0.978,95%CI:0.963~0.992,P=0.003)。Kaplan-Meier生存曲线显示随着胚胎移植周期数增多,4组患者单个取卵周期累积活产率比较差异有统计学意义(P<0.05)。结论中心性肥胖对女性体外受精-胚胎移植的妊娠结局造成不良影响。

水稻秸秆拆解工艺参数优化及纤维自交织结构

大尺寸高长径比纤维是影响非织造秸秆纤维生态毯质量的关键。机械揉搓是获得高长径比纤维的最佳处理技术工艺。该研究探究了揉丝机主轴转速和锤齿间隙对不同含水率秸秆纤维拆解揉丝的影响,其工艺参数为主轴转速、锤齿间隙及物料含水率,指标输出为秸秆丝化率与标定单位生产率,并对纤维自交织结构特性进行评价。结果表明,采用Box-Behnken响应面法(response surface method,RSM)开发了一个可确定输入和输出参数间的函数,2种评价指标模型均具有较高的可信度,决定系数分别为R^(2)>0.95,R^(2)>0.84。优化数学模型工艺参数:含水率41.2%,主轴转速2498 r/min,锤齿间隙12.84 mm组合下秸秆丝化率达96.93%,标定单位功率生产率为29.33 kg/(kW?h)。大尺寸高长径比秸秆纤维长度>70 mm和长宽比>80比例增幅分别达120.55%和16.01%,有效改善纤维自交织能力,所开发的RSM模型秸秆的实际揉搓拆解丝化率达96.27%,加工成本降低27.50元/t,可广泛应用于生产大尺寸纤维秸秆基高值农用制品。该研究为生物质秸秆的有效循环利用和高值化材料产业的绿色可持续发展提供重要依据和技术支撑。

大荷载矿石堆场中深厚吹填软土的地基处理及后评价

吹填淤泥形成陆域是资源利用和环境保护方面的优质解决方案,但当前吹填软土形成陆域的工程中,多数为荷载较小的堆场、工业园区道路、绿化区等。以青岛港董家口港区矿石码头工程20万吨级散货泊位后方预留堆场区的地基处理工程为例,对该工程的设计、施工及使用后6年的情况进行详细阐述,从多个角度展示深厚吹填软土的演变情况,详细介绍土体含水量、孔隙比、抗剪强度等指标在不同时期的变化,对比施工期沉降计算和监测数据,分析不同时期抗剪强度指标下矿石堆存的高度。结果表明,在大荷载矿石堆场中采用吹填软土形成陆域是可行的,通过合理的地基处理方式和有序增加堆存荷载,最终可使矿石堆场达到满载堆存。

岩石类材料直接拉伸破坏的FDEM数值模拟

有限元-离散元耦合算法(FDEM)在岩石裂纹扩展模拟中广泛应用,尤其在直接拉伸模拟中用于参数校核。然而,模拟结果通常受到拉伸速率和网格尺寸的影响。本文首先阐述FDEM基本原理;然后,建立直接拉伸数值计算模型,探究拉伸速率、网格尺寸及高径比对破坏模式和力学参数的影响;最后,给出直接拉伸模拟中建议采用的拉伸速率和网格尺寸。研究结果表明:随着拉伸速率增加,试样抗拉强度、破坏程度和峰值应变率增加,而平均弹性模量减小;在较低拉伸速率下(v≤0.01 m/s),试样仅产生1条主拉伸裂缝;当拉伸速率较高时,有分支裂缝出现在主拉伸裂缝上侧。网格尺寸对抗拉强度、峰值应变率和平均弹性模量的影响较小,但对破坏模式和破坏程度的影响较显著。随着高径比增加,试样的抗拉强度、破坏程度和峰值应变率增大,但平均弹性模量呈相反趋势,并且高径比对破坏程度的影响较为显著。建议在直接拉伸模拟中使用0.01 m/s的拉伸速率,并将网格尺寸限制在1.5 mm以内。

前混合水射流喷丸单丸粒冲击特性研究

单丸粒冲击特性是研究混合射流表面喷丸强度和覆盖率的基础指标,丸粒特性与靶材特性均会对冲击后的弹坑形态产生影响。以不同热处理后的18CrNiMo7-6低碳合金钢为靶材,研究了不同丸粒冲击条件下的弹坑特性。从弹坑形成机理出发,建立了单丸粒冲击弹坑尺寸模型,并通过试验研究,修正了高硬度靶材弹坑的误差,使弹坑深度预测误差降低到30%以下。在此基础上,研究了弹坑相关特征参数(深径比、坑深坑直径占比、脊高)的规律。结果表明,丸粒硬度和靶材硬度对深径比以及坑深直径占比影响最为显著,而弹坑周边的脊状结构只存在于低硬度靶材中。各参数对脊高的影响由大到小分别为丸粒直径、丸粒硬度和丸粒速度。

宽高比对煤柱型冲击地压影响规律的实验研究

我国深部煤炭开采日趋复杂,区段煤柱在采动、构造或坚硬顶底板影响下极易诱发煤柱型冲击地压,煤柱型冲击地压的防治已成为煤矿安全高效开采的难题,研究不同宽高比条件下区段煤柱的力学性能及冲击破坏特性对煤柱型冲击地压防治具有积极意义。采用不同宽高比煤样的“岩-煤-岩”组合体进行了单轴压缩实验,通过分析煤岩组合体的冲击倾向性、动态破坏特征、分形维数和声发射特征参数等,研究了宽高比对煤柱冲击破坏的影响规律。结果发现:①煤柱的宽高比对煤岩组合体的冲击倾向性具有显著影响,宽高比不小于2∶1时,其冲击能量指数K_(E)为1.82~2.65,冲击倾向性无明显变化;小于2∶1时冲击倾向性呈先升高后降低的趋势,1∶1时K_(E)最大,达到了15.43。②随宽高比减小,煤岩组合体破坏特征依次表现为:拉压破坏—压剪破坏—拉剪破坏。煤柱宽高比为5∶1~3∶1时,煤岩组合体破坏较为缓慢;宽高比为2∶1时开始出现片状煤屑弹出,冲击破坏剧烈程度较低;宽高比为1∶1和0.75∶1时,具有明显的冲击破坏特性;宽高比为0.5∶1时,煤岩组合体整体稳定性下降,相对0.75∶1煤岩组合体煤柱破坏的剧烈程度降低。③峰后声发射能量释放率与分形维数D变化规律相似,均随宽高比减小呈先升高后降低的趋势。宽高比不小于2∶1时,煤岩组合体破坏过程中能量持续释放时间较长,煤柱破坏平缓;宽高比为1∶1时,能量释放率和D值明显增大,相较宽高比不小于2∶1煤岩组合体的能量释放率增大了约4倍,D值增大了0.18~0.23,煤柱冲击破坏最为剧烈;宽高比0.75∶1煤岩组合体能量释放率与D值分别降低了约10%和0.01,破坏剧烈程度与1∶1煤岩组合体相近;宽高比减小至0.5∶1时,相关参数的降低幅度约为0.75∶1煤岩组合体的6倍,破坏剧烈程度相对较小。研究表明:宽高比对煤柱的冲击破坏具有显著影响,整体上,煤柱冲击破坏剧烈程度随宽高比减小(5∶1~0.5∶1)呈先升高后逐渐降低的趋势;煤柱宽高比大于3∶1时,煤柱冲击危险性相对较小,煤柱宽高比为1∶1和0.75∶1时冲击危险性较大,0.5∶1次之。