高处作业吊篮提升机承载能力影响因素的研究

基于摩擦传动理论,对影响高处作业吊篮提升机承栽能力的因素进行了分析,得到了其与摩擦系数、包角和压盘所受的正压力之间的数量关系,并通过实验验证了理论分析的结果.由于制造,安装及使用的原因,提升机有时会产生"融绳"和打滑现象.本文的分析结果对提高提升机的设计,制造水平,充分开发其应用潜力,排除使用故障有一定的指导意义.     

高处坠落、起重伤害事故的分析与对策

高处坠落和起重事故是钢结构安装工程施工中发生频率和危害最大的两种安全事故。在安全施工实践的基础上,分析了此类事故发生的各种因素,提出了防范措施。     

高处作业吊篮安全锁的制动性能分析

基于锁绳机构的静力学分析,讨论了锁芯和琵琶板的几何参数以及安装尺寸对摆臂式安全锁锁绳性能的影响.分析结果表明,锁芯夹槽所张圆心角越大,锁绳性能越好;琵琶板月牙孔的几何中心到销轴几何中心的距离以及琵琶板二月牙孔的几何中心之间的距离越大,锁绳性能越好;摆臂的旋转中心到工作钢丝绳出绳口的竖直距离以及到工作钢丝绳的水平距离越大,锁绳性能越好.     

浅谈建筑施工现场高处坠落原因

近年来，随着我市经济的迅速发展，高层建筑和超高建筑的大量兴起，由于少数施工单位由于不重视或忽视高处作业在施工过程中的重要作用。因而不断导致高坠伤亡事故频频的发生。高处坠落事故是施工伤亡事故的元凶，有效防止高处坠落事故对预防建筑施工安全事故有着十分重要的意义。     

基于改进证据理论的装配式建筑施工高处坠落风险评价

为降低不确定信息对装配式建筑施工中高处坠落风险评价的影响,针对我国当前装配式建筑施工特点,构建了基于改进证据理论的装配式建筑施工高处坠落风险评价模型.通过实地调研及专家咨询,从人、物、环境、管理四个维度建立了装配式建筑施工高处坠落风险评价指标体系.在此基础上,采用结构熵权法确定指标权重.基于权值分配与矩阵算法对DS证据...     

U型高处作业平台提升吊点位置分布

目的 研究U型高处作业平台的组成结构,探讨选择U型平台提升吊点分布位置的合理性.方法 利用最优吊点原则及悬吊平台结构尺寸,对平台吊点基本位置进行初步确定,并分析活荷载的变化对平台稳定性的影响,通过计算吊点处随活载荷变化而产生的最大载荷,确定钢平台所选用提升机类型.结果 确定了三吊点作业方案满足U型钢平台提升要求和设计要求.根据计算得出的平台重心位置及钢平台结构尺寸,确定了钢平台3个提升吊点分别设在短边2个1.5 m钢平台连接处和两个长边上2.5 m平台及1.5 m平台连接处,并且确定了此型钢平台所选用提升机类型为ZLP630型提升机.结论 合理地选择吊点的分布位置保证了U型平台在运动过程中的平稳性,极大地改善了U型平台整机安全性,对异型高处作业平台推广应用具有重要实用价值.     

基于社会网络分析法的建筑施工高处坠落事故成因研究——以华东地区为例

明确建筑施工高处坠落事故发生的关键成因及其关联性,可以有效预防事故的发生,为此类事故的防控工作提供参考。文章收集2012—2021年间华东地区的145份建筑施工高处坠落事故调查报告,基于文本挖掘进行结构化处理,识别出25项成因要素,运用社会网络分析法,借助社会网络分析软件Ucinet构建建筑施工高处坠落事故成因关系网络,分析了整体网络密度、个体网络密度、网络中心性以及核心边缘结构。结果表明：主体责任不落实、防护措施不到位、监督检查不力、现场管理不到位、安全教育培训不到位、安全意识淡薄、防护用品使用不当等7项要素是高处坠落事故中的关键成因,可将其作为建筑施工高处作业的安全防控重点,以减少高处坠落事故的发生。     

基于BIM和RFID的模板支撑架高处坠落预警管理分析

为减少并预防模板支撑架高处坠落事故的发生,提高安全预警管理水平。在对引发架体高处坠落事故危险源进行辨识与分析的基础上,依据架体坠落对象的不同对危险区域及预警等级进行了划分。同时基于预警管理信息需求分析构建了包含信息采集层、网络层、交互层、应用层的系统框架,并最终构建了基于建筑信息模型和射频识别技术的模板支撑架高处坠落事故预警管理系统运行流程图。结果表明,该系统能够通过对危险源信息采集、定位跟踪、危险区域自动识别与预警提示,进而实现对架体搭拆人员与架上施工人员高处坠落事故的可视化分析与智能化预警。     

能这样进行危险源辨识吗

一些组织在列出的《危险源清单》中，辨识的“危险源”是物体打击、车辆伤害、机械伤害、起重伤害、触电、灼烫、火灾、高处坠落、爆炸、中毒；还有一些组织列出的“危险源”是淹溺、坍塌、冒顶片帮、透水……许多咨询师、审核员也认同此说法，一些职业健康安全管理体系的书籍也是如此表述。     

Research advances of un-symmetric constitutive theory of anisotropic viscoelastic liquids and its hydrodynamic behavior

Research advances of un-symmetric constitutive equation of anisotropic fluid,influence of un-symmetric stress tensor on material functions,vibrational shear flow of the fluid with small amplitudes and rheology of anisotropic suspension were reported.A new concept of simple anisotropic fluid was introduced.On the basis of anisotropic principle,the simple fluid stress behaviour was described by velocity gradient tensor F and spin tensor W instead of velocity gradient tensor D in the classic Leslie-Ericksen continuum theory.Two relaxation times analyzing rheological nature of the fluid and using tensor analysis a general form of the constitutive equation of co-rotational type was introduced.More general model LCP-H for the fluid was developed.The unsymmetry of the shear stress was predicted by the present continuum theory for anisotropic viscoelastic fluid-LC polymer liquids.The influence of the relaxation times on material functions was specially studied.It is important to study the unsteady vibrational rotating flow with small amplitudes,as it is a best way to obtain knowledge of elasticity of the LC polymer,i.e.dynamic viscoelasticity.For the shear-unsymmetric stresses,two shear stresses were obtained thus two complex viscosities and two complex shear modulus(i.e.first and second one) were introduced by the constitutive equation which was defined by rotating shear rate introduced by author.For the two stability problems of fluid,such as stability of hydrodynamic flow and orientational motion,were discussed.The results show that the polymer suspension systems exhibit anisotropic character.The PNC systems can exhibit significant shear-thinning effects.For more concentrated polymer nano-suspensions,the first normal stress difference change from positive to negative,which is similar to LC polymer behavior.     

当前民办高校融资难的成因及对策

针对民办高校所需办学经费无国家财政拨款,全部为自筹资金的现状,分析了形成当前民办高校融资难的原因,既有信贷政策、银行方面的因素,也有民办高校自身的因素.提出民办高校要生存,要发展,光靠举办者投入或捐赠以及每年的学费收入是不够的,还需要积极拓展更多融资渠道解决办校融资难的问题.     

脉冲振动预磁器的研究和设计

根据细粒磁性物回收工艺中需要使用预磁器的要求,研究预磁器的工作时序、充放电回路的电器元件特性和电路电压、电流特征.设计的电磁预磁器磁场强度高,能耗低,性价比高.对预磁化电路展开理论计算和推导.首次提出脉冲振动预磁器系统结构,将RLC电路振荡波形转变为振动波形,形成"脉振"高场强,延长了线圈的使用寿命.经实际运行检验,该装置性能稳定,效果好,能耗低,每小时耗电仅0.8 kW,在预磁器领域是一项创新的实用技术.     

城市污水热能资源化的基础研究

作为城市污水热能资源化的基础研究,根据理论分析方法,对有效利用城市污水所赋存的热能时,其节能效果和对减轻大气污染的作用进行了若干分析和探讨.分别计算了流量为1 m3/s时城市污水赋存的热量,以及采暖面积为1万m2时所需的城市污水及赋存的热量,与空调、锅炉相比产生相同热量时的一次能和二次能的消减量,以及相应条件下的污染物年间(采暖期)消减量等.     

Vibrational shear flow of anisotropic viscoelastic fluid with small amplitudes

Using the constitutive equation of co-rotational derivative type for anisotropic viscoelastic fluid-liquid crystalline(LC),polymer liquids was developed.Two relaxation times are introduced in the equation:λn represents relaxation of the normal-symmetric stress components;λs represents relaxation of the shear-unsymmetric stress components.A vibrational rotating flow in gap between cylinders with small amplitudes is studied for the anisotropic viscoelastic fluid-liquid crystalline polymer.The time-dependent constitutive equation are linearized with respect to parameter of small amplitude.For the normal-symmetric part of stress tensor analytical expression of the shear stress is obtained by the constitutive equation.The complex viscosity,complex shear modulus,dynamic and imaginary viscosities,storage modulus and loss modulus are obtained for the normal-symmetric stress case which are defined by the common shear rate.For the shear-unsymmetric stress part,two shear stresses are obtained thus two complex viscosities and two complex shear modulus(i.e.first and second one) are given by the constitutive equation which are defined by rotating shear rate introduced by author.The dynamic and imaginary viscosities,storage modulus and loss modulus are given for each complex viscosities and complex shear modulus.Using the constituive equation the rotating flow with small amplitudes in gap between two coaxial cylinders is studied.     

科技期刊版式设计略谈

对科技期刊版式设计中的标题、插图与空白的处置进行了分析探讨,认为科技期刊版式设计在总体上应是追求格式一致与节奏变化的统一,整体性与连贯性的统一.布局合理的版式设计带给期刊的是整体的和谐美,别具风格的版式设计标志着期刊的个性特征.     

玉米中转基因成分的定性PCR检测

利用改良 CTAB 法提取玉米产品的基因组 DNA,应用 PCR 检测方法,并以玉米特异性内源基因 IVR 为内参,花椰菜花叶病毒 35S 启动子(CaMV35S 启动子)、农杆茵胭脂碱合成酶终止子(NOS终止子)为靶基因检测玉米中是否存在转基因成分.实验结果表明,有些玉米样品中存在转基因成分,表明市场上存在未经标识的转基因玉米及其加工品.     

利用双折射晶体实现双偏振光叠加的教学研究

利用晶体的双折射现象和它的基本性质,采用现代光纤和CCD摄像放大技术手段研究了双偏振光的叠加和干涉现象,讨论了学生在教学中不易理解的难点问题.     

单极世界军备竞赛微分方程稳定性的研究

对一国或多国军备竞赛的数学模型进行了研究.单独一国的经济增长服从Horrod-Domer模型,但当多国一起竞争时,弱国将遭受前所未有的严重挑战.通过研究超级大国、另一大国和弱国这三个国家之间军备竞赛稳定性问题,得到了军备竞赛稳定性的条件.     

Effect of sediment on vertical dynamic impedance of rock-socketed pile with large diameter

Based on the fictitious soil pile model, the effect of sediment on the vertical dynamic impedance of rock-socketed pile with large diameter was theoretically studied by means of Laplace transform technique and impedance function transfer method. Firstly, the sediment under rock-socketed pile was assumed to be fictitious soil pile with the same sectional area. The Rayleigh-Love rode model was used to simulate the rock-socketed pile and the fictitious soil pile with the consideration of the lateral inertial effect of large-diameter pile. The layered surrounding soils and bedrock were modeled by the plane strain model. Then, by virtue of the initial conditions and boundary conditions of the soil pile system, the analytical solution of the vertical dynamic impedance at the head of rock-socketed pile was derived for the arbitrary excitation acting on the pile head. Lastly, based on the presented analytical solution, the effect of sediment properties, bedrock property and lateral inertial effect on the vertical dynamic impedance at rock-socketed pile head were investigated in detail. It is shown that the sediment properties have significant effect on the vertical dynamic impedance at the rock-socketed pile head. The ability of soil-pile system to resist dynamic vertical deformation is weakened with the increase of sediment thickness, but amplified with the increase of shear wave velocity of sediment. The ability of soil pile system to resist dynamic vertical deformation is amplified with the bedrock property improving, but the ability of soil-pile system to resist vertical vibration is weakened with the improvement of bedrock property.     

Rheological characteristics of aged asphalt binder

Different aging levels(RTFOT,PAV-10h,PAV-20h and PAV-30 h) of asphalt binders with various mass ratios of mineral powder to asphalt(0,0.4,0.8,1.2,1.6,2.0) were used to investigate the rheological properties of aged asphalt binders with respect to their short and long terms aging characteristics.Viscosity test,dynamic shear test and creep test were conducted.The test results indicate that the viscosity of aged asphalt binder increases sharply with the extension of aging period.Complex shear modulus of aged asphalt increases,which indicates that the stiffness of asphalt binders can increase.The phase angle for aged asphalt binders reduces,which indicates that the elastic portion for viscoelastic property of asphalt binders increases.|G*|·sin δ increases after aging procedure which means that the fatigue resistance becomes poor.The creep test results show that creep strain curves varies remarkably for virgin and aged asphalt binders.The total strain during loading period and the permanent strain decreases significantly for aged asphalt binders,which implies that the elastic portion increases and the viscous portion decreases.