The Importance of Design Spectra and Site Class for the Design of High-Rise Buildings

On November 26,2019 a strong earthquake of magnitude M6.4 occurred close to the City of Durrës,Albania(15.6 km WSW(west southwest)of Mamurras and 22 km SSW(south southwest)of Durrës),causing fatalities and considerable damages in many buildings.In this article we present and analyze,by means of observational data and numerical simulation,the behavior under this earthquake of an 8-floor RC(reinforcement concrete)building,by using design spectra referring to KTP-N.2-89 and Eurocode 8.The main purpose of the authors is to better understand and evaluate the seismic performance of high-rise buildings under the design spectra with a period of soil oscillation close to the fundamental period of the structure.

A simulation-based nonlinear site amplification model for ground-motion prediction equations in Japan

In this manuscript we present a nonlinear site amplification model for ground-motion prediction equations(GMPEs)in Japan,using a site period-based site class and a site impedance ratio as site parameters.We used a large number of shear-wave velocity profiles from the Kiban-Kyoshin network(KiK-net)and the Kyoshin network(K-NET)to construct the one-dimensional(1D)numerical models.The strong-motion records from rock-sites in Japan with different earthquake categories and taken from the Pacific Earthquake Engineering Research Center dataset were used in this study.We fit a set of 1D site amplification models using the spectral amplification ratios derived from 1D equivalent linear analyses.Parameters of site impedance ratios for both linear and nonlinear site response were included in the 1D model.The 1D model could be implemented into GMPEs using a new proposed adjustment method.The adjusted site amplification ratios retain the nonlinear characteristics of the 1D model for strong motions and match the linear amplification ratio in GMPE for weak motions.The nonlinearity of the present site model is reasonably similar to that of the historical models,and the present site model could satisfactorily capture the nonlinear site response in empirical data.

EVALUATION OF SITE QUALITY FOR DAHURIAN LARCH FORESTS

The site index table, site class table and quantizing model ofdahurian larch forests were formed based on 418 temporary plots and 179 dominant stem analysis trees. By testing raw data which were not used to form the site index table, the site index table of plantations was validated. The site index table or site class table can be used in timber stands according to the intensive degrees of forest management. The quantizing model can be used in cutover, deforested and nonforested areas.

THE STUDY ON SITE QUALITY EVALUATION FOR DAHURIAN LARCH(LARIX GMELINII RUPR.)

Site quality of larch(Larix gmelinii Rupr.)in Da Xingan Mountain in InnerMongolia was studied systematically with about 1000 temporary plots and computersoftware.The nature of site class and site index curve was discussed in view of generalmathematical model of height growth.The height growth of dominant tree of four divisionsof forest stands were studied and site index tables were constructed respectively.In orderto unify the comparing standard and convenience for management in this region,site indextable was constucted too.Based on discussing the action and accuracy of forest type,aseries of site quality evaluation(forest type-site index class-site index)was suggested.

On the Disadvantages of the NEHRP Soil Classification

The study of the relationship of local ground conditions with the parameters of seismic vibrations carried out by the section of engineering seismology called seismic microzonation. In this branch of applied science radical changes have taken place at the end of the last century. The Commission on Seismic Safety of the National Institute of Building Sciences of the United States has developed new recommendations, which are significantly different from all that used in the world practice of anti-seismic construction. The main provisions of this NEHRP (National Earthquake Hazards Reduction Program) classification adopted in many national building codes, including Eurocode 8. At the same time, a number of papers appeared in subsequent years criticizing the use of the NEHRP soil classification. This article examines in detail and, most importantly, comprehensively the shortcomings of the NEHRP classification.

Surveillance of Surgical Site Infections: A Public Health Emergency in a Regional Hospital of Northern Benin. A Prospective Observational Pilot Study

Background: Surgical site infections (SSIs) are considered as result of the healthcare quality in hospitals. Objective: to study SSI at Saint Jean de Dieu Hospital Tanguieta (SJDHT), prior to the implementation of a permanent monitoring system. Method: transversal, and descriptive study with prospective data collection was performed from 1 July to 31 janvier 2017 in the department of general surgery of SJDHT. The hospital lacks in a microbiology unit. All patients who underwent surgery during this period were included and the monitoring lasted one month. SSIs diagnostic was carried out according to WHO criteria as described in the Practical Guide for the Prevention of Nosocomial Infections published in 2002. Statistical tests (χ-square and Student’s t-test) were applied and p 0.05 were statistically significant. Results: Of 343 patients recorded, 105 (30.6%) had SSI. Their age averaged 40.3 years and the sex-ratio (men/women) was 2.8. The emergency surgery resulted in a 50.0% rate of SSI (p = 0.00). The SSI rate for clean and clean-contaminated surgery was 6.3% against 94.6% for infected surgery (p = 0.00). The SSI rates were 100% and 66.7% for NNISS = 2 and NNISS = 1 (p = 0.00), respectively. Superficial SSI rate was 13.3%, while deep SSI and organ/space SSI were 46.7% and 40%, respectively. The hospital stay of patients with SSI was three times longer than the length of patients without SSI (p = 0.00). Conclusion: SSIs are real burden at SJDHT. Appropriate measures must be adopted to reduce its prevalence.

基于多标签卷积神经网络的结构损伤识别

准确识别结构多位置损伤一直是结构损伤识别的难题。为提升结构多位置损伤识别的准确率,提出一种基于卷积神经网络(CNN)的多标签分类(MLC)方法(CNN-MLC)进行结构损伤识别。该方法将结构多个位置损伤识别转换为多标签分类问题,每个损伤位置均用一个对应的标签表示;利用CNN强大的特征提取能力,深入挖掘不同损伤工况之间公共损伤位置的相关性,实现结构多位置损伤识别。通过四层框架结构和一座铁路连续梁桥多位置损伤识别验证了CNN-MLC方法的识别准确率,并将其识别结果与基于CNN的多类别分类(MCC)方法(CNN-MCC)和基于示例差异化算法(InsDif)的多标签分类方法(InsDif-MLC)进行了对比。结果表明:框架结构在两位置和三位置损伤工况下,CNN-MLC方法比CNN-MCC方法的识别准确率分别提升2.50%和9.64%,比InsDif-MLC方法识别准确率提升17.50%和29.28%;对于铁路连续梁桥的两位置损伤和三位置损伤,CNN-MLC方法比CNN-MCC方法识别准确率提升1.63%和6.85%,比InsDif-MLC方法识别准确率提升4.18%和18.49%;随着损伤位置数量的增加,CNN-MLC方法的识别准确率显著提升。

“双一流”背景下资源勘查工程一流专业建设与探索

随着深入实施科教兴国战略、人才强国战略、创新驱动发展战略,高等教育必然要担当起新的使命和时代重任,而专业建设是高等教育体系的重要支柱,是人才培养的基础平台,资源勘查工程专业关系着我国能源资源安全,为此,在充分分析河南理工大学资源勘查工程专业建设基础上,查找目前存在的问题,对标“一流专业”和“新工科”建设要求,结合河南理工大学特色优势,探索“双一流”背景下资源勘查工程专业的建设路径,总结取得的一些成效,以期进一步促进资源勘查工程专业内涵式发展,同时为我国其他兄弟院校相关专业建设提供借鉴,为实现地球科学强国目标贡献科技和人才力量。

现地教学在雷达装备类课程中的应用

为积极推进教育教学改革创新,坚持开放办学理念,以海军大连舰艇学院雷达装备类课程为例,分析了学院当前雷达装备类课程教学中存在的问题,提出了现地教学的内涵及优势,给出了现地教学在雷达装备类课程中的应用方法.教学实践表明,采用现地教学有效提高了学员装备实作考核成绩.这为其他装备类课程现地教学提供了参考.

立地因子对半天然杉阔混交林生长的影响

为高质量培育杉木Cunninghamia lanceolata速生丰产大径材和檫树Sassafras tzumu珍贵用材,精准提升森林经营成效,以13~14 a生半天然杉阔混交林为研究对象,分析不同坡向、坡位、立地等级对其生长的影响。结果表明,3个坡向杉木胸径、树高和材积生长量表现为阴坡>半阴坡>半阳坡,不同坡向间差异极显著(P<0.01);木荷Schima superba和檫树的胸径、树高、材积生长量表现为半阳坡>半阴坡>阴坡,不同坡向间木荷生长差异不显著,檫树胸径、材积生长差异极显著(P<0.01)。3个坡位杉木、檫树的胸径、树高、材积生长量表现为下部>中部>上部,杉木胸径、树高、材积生长差异均为极显著(P<0.01);檫树胸径、树高生长差异显著(P<0.05),材积生长差异极显著(P<0.01);木荷胸径、树高、材积生长差异不显著。2个立地级杉木、木荷、檫树胸径、树高和材积生长量表现为Ⅰ立地级>Ⅱ立地级,杉木树高生长差异显著(P<0.05),胸径、材积生长差异极显著(P<0.01);木荷胸径、材积生长差异不显著,树高生长差异显著(P<0.05);檫树胸径、树高、材积生长差异极显著(P<0.01)。在一代杉木林阴坡、山坡下部、Ⅰ立地级条件下,连栽杉木混生天然檫树林分中,13~14 a生杉木平均树高12.4~13.9 m、平均胸径14.0~14.8 cm、蓄积量201.45~248.90 m^(3)·hm^(-2)、年均蓄积生长量15.50~19.15 m^(3)·hm^(-2),达到速生丰产林大径材指标。

黔北金佛山方竹林质量及其影响因素

亚优层竹林质量及影响因素是竹林生态学研究的热点及难点。在黔北大娄山金佛山方竹(以下简称方竹)中心分布区3县13个乡(镇)调查了92个样地,其中石灰土方竹林样地39个、黄(棕)壤方竹林样地53个,系统分析了不同类型方竹林质量变化规律及其影响因素。结果表明:1)主要立地、土壤指标对方竹林质量(由平均胸径、高度、密度和生物量组成)的贡献率变幅为4.10%~28.02%,是方竹林的重要影响因子;石灰土方竹林、黄(棕)壤方竹林及方竹林平均胸径、高度、密度及生物量与主要立地、土壤指标相关性显著的指标对数量占比分别为28.13%、15.63%和25.00%。2)各龄级(Ⅰ~Ⅳ)方竹质量指标对方竹林质量的贡献率变幅为41.77%~87.74%,是方竹林的主要影响因子。石灰土方竹林、黄(棕)壤方竹林及方竹林质量指标与各龄级立竹质量指标相关性显著的指标对数量占比分别为76.56%、64.06%和73.44%,立竹龄级对不同类型方竹林质量的影响随立竹年龄增大而降低。3)乔木、灌木主要指标对方竹林质量的贡献率变幅为3.70%~30.21%,是方竹林不可或缺的影响因子。石灰土方竹林、黄(棕)壤方竹林及方竹林质量指标与乔木和灌木结构指标、乔木多样性指数相关性显著的指标对数量占比为2.50%、12.50%和20.0%。因此,合理选择立地、科学调控立竹龄级及乔木、灌木结构是提高方竹林质量的重要途径。

中国与伊朗抗震规范地震作用对比研究

介绍了伊朗抗震规范的抗震设防目标与方法、场地类型、地震风险分区、设计反应谱以及基底剪力的计算,并与《建筑抗震设计规范》相关内容进行了对比。结果表明,伊朗规范根据结构重要性对建筑有选择性地做“两水准”抗震设防;基于平均剪切波速伊朗规范中的Ⅰ类场地近似于中国规范的Ⅰ0场地,其余各类场地之间无直接对应关系;伊朗规范设计反应谱动力系数随场地类型与地震风险分区变化,在低地震风险区的软弱场地上动力系数峰值高达3.25;伊朗规范地震作用基于“中震”计算,经结构性能系数折减后的基底剪力:高延性混凝土框架的基底剪力比中国规范小,低延性混凝土框架的基底剪力比中国规范大得多,中延性混凝土框架的基底剪力与中国规范的大小比较结果在不同场地不同周期段表现不同。

基于某高烈度场地的建筑结构设计关键技术分析研究

为有效提升高烈度场地建筑结构设计质量,保证建筑使用安全,研究依托某高烈度区Ⅳ类场地综合楼项目实例,提出了设置应力释放孔、阻尼器及实施两阶段的设计方案,并通过具体计算对方案抗震效果进行分析,结果显示:(1)设置应力释放孔能显著降低管桩施工对周边土体的挤压作用;(2)设置阻尼器可减弱建筑结构在地震作用下的动力响应;(3)对于高烈度及Ⅳ类场地区域设防等级要求较高的建筑结构,可采取两阶段设计形式实施抗震设计。

地方高校一流本科专业建设点生态定位研究

增强地方高校一流本科专业建设点的吸引力和品牌竞争力,关键在于专业的精准定位,满足利益相关者需求。探析“一流本科专业”深层含义,结合教育生态学、生态位理论及定位理论,提出“专业生态定位”的概念,阐释其原理,为专业生态位有效分离、错位竞争及精准价值点选择提供理论支撑。研究发现,地方高校普遍存在的人才培养方案同质化、品牌形象缺少差异化、成长目标模糊和价值定位不清晰等问题,降低了其专业应有的创新性和特色,削弱了其成为教育标杆的潜力。依据“专业生态定位”原理提出需求细分与错位营销、对象选择与形象重塑、标准建设与引领需求、缝隙定位与创造价值等针对性策略,为地方高校一流本科专业建设指明了改进方向。

神经外科颅脑手术Ⅰ类切口手术部位感染的危险因素分析

目的 分析神经外科颅脑手术Ⅰ类切口手术部位感染的危险因素。方法 通过医院感染实时监测杏林系统提取2022年1月—12月在德州市人民医院实施神经外科开颅Ⅰ类切口手术的256例患者的临床资料进行回顾性分析,统计感染发生率。发生感染者12例纳入感染组,未发生感染244例者纳入未感染组,Logistic回归性分析感染原因和独立危险因素。结果 单因素分析,感染组糖尿病、低蛋白血症、再次手术、脑室引流、手术时间与未感染组对比,差异有统计学意义(P均<0.05)。多因素分析:糖尿病、低蛋白血症、再次手术、脑室引流、手术时间≥4 h为诱发感染的独立危险因素(OR=2.142,1.841,1.264,1.041,1.108,P均<0.05)。结论神经外科颅脑手术Ⅰ类切口手术部位感染的出现与糖尿病、低蛋白血症、再次手术、脑室引流、手术时间较长等因素密切相关,为有效避免手术切口感染需要展开针对性干预措施。

基于林分潜在生长量的立地质量评价方法与应用

【目的】提出一种基于林分潜在生长量的立地质量评价方法,为精准提升森林质量提供可靠依据。【方法】首次严格定义潜在立地生产力概念,推导出潜在生产力和现实生产力的模型和计算方法,提出立地元素-林分元素-林分生长类型-现实生产力和潜在生产力模型-落实到地块的立地质量制图技术流程,并以吉林省针阔混交林为例,利用4期一类清查固定样地数据,基于林分潜在生长量的立地质量评价方法开展案例研究。【结果】影响吉林省林地立地质量的主要立地因子包括地貌、海拔、坡位、坡度、土壤类型和腐殖质层厚度;采用立地类型约束的树高生长分级法,将6个因子组合的立地类型分为5个等级,针阔混交林不同立地等级的林分平均高、断面积和蓄积量生长模型具有较好的生物学意义和统计可靠性,决定系数(R^2)分别为0.991 8、0.986 6和0.984 2; 5个立地等级的潜在蓄积生产力在3.6～5.8 m^3·hm^(-2)a^(-1)间,并给出了立地潜在生长量对应的合理林分密度。【结论】基于林分潜在生长量的立地质量评价方法适用于纯林和混交林,可以回答一定立地的最大生产力及现存林分通过密度调控可以提高多少生产力。

设计地震动参数确定中的场地影响考虑

讨论了场地条件对场地设计地震动参数的影响问题，对国际上一些国家的抗震设计规范考虑该问题的相关规定作了介绍和分析，探讨了抗震设计规范对该问题处理的发展趋势．基于相关的强震纪录统计分析和场地模型计算反应分析已有的结果．研究了场地条件对场地设计地震动参数的影响特点和规律，重点考虑了场地类别和场地土体非线性的影响．结合这些分析与探讨结果，建议了用于不同类别场地设计地震动参数确定的一组经验系数．

基于不同立地质量的森林蓄积量遥感估测

森林蓄积量遥感估测在森林资源管理中具有十分重要的意义。以建德市为研究区,利用2007年TM遥感影像和2007年森林资源2类调查数据,对杉木树种分立地质量等级和不分地位等级2种类型建立蓄积量的遥感估测模型,并进行精度检验。其中立地质量等级依据小班平均高和平均年龄建立的地位级表划分为好、中、差3种类型,以每个小班的总蓄积量为因变量,小班各单个遥感因子信息总量为自变量。结果表明:以TM遥感影像主成分分析中第1主成分为自变量的模型拟合效果最好,相关系数R均在0.67以上,最高为0.868;利用预留独立样本对模型精度进行验证,不分地位级总体估测精度为90.31%,分立地质量等级好、中、差3种类型总体的估测精度分别为96.1%、97.24%、95.56%,分立地质量类型建模的精度明显优于统一建模的精度。研究结果为森林蓄积量遥感估测提供一种改进的思路,且为提高森林生物量和碳储量遥感估测精度提供一种参考方法。

不同立地条件红壳竹竹材物理力学性质的比较

测定了不同地位级不同竹龄红壳竹竹材的物理力学性质。结果表明 :不同地位级红壳竹竹材的基本密度和力学性质都随竹龄的增大而提高 ;径向、弦向和体积全干缩率随竹龄增大而减少 ;地位级Ⅱ的竹材的基本密度和力学性质高于地位级Ⅰ ,径向、弦向和体积全干缩率小于地位级Ⅰ ;不同地位级的竹材基本密度、顺纹抗压强度、顺纹抗拉强度和弦向抗弯强度有显著差异 ,而径向抗弯强度无显著差异。表 4参

基于不同立地质量的杉木生物量遥感估测

[目的]研究不同立地质量对杉木生物量遥感估测精度的影响,为进一步提高和完善森林生物量遥感监测体系提供一种新的思路和方法。[方法]以2007年建德市森林资源二类调查数据和TM影像为研究材料,采用蓄积量—生物量换算因子连续函数法计算杉木林生物量和地位级法评价立地质量等级,比较杉木立地质量好、中等、差和不分地位等级4种生物量遥感估测模型,并进行精度检验。[结果]表明:(1)以TM遥感影像主成分分析中第一主成分为自变量的模型拟合效果最好,决定系数R2均在0.69以上,最高0.855。(2)利用预留独立样本对模型精度进行验证,不分地位级总体估测精度为87.78%,分立地质量等级好、中、差3种类型总体估测精度分别为97.37%、95.82%、98.23%。分不同立地质量类型可以提高杉木生物量遥感估测精度。[结论]研究结果为森林生物量遥感估测提供一种改进的思路,且为提高森林生物量和碳储量遥感估测精度提供一种参考方法。