考虑土-结构相互作用时高层建筑的横、顺风振响应分析

本文在不考虑土-结构相互作用时结构响应分析的基础上,引入了地基阻抗函数,对考虑横向风荷载作用下的高层建筑提出土-结构相互作用,最后给出算例,考虑横风向、顺风向作用下的结构响应与仅考虑顺风向作用下的结构响应进行了比较,以及考虑横、顺风向及土-结构相互作用下的结构响应与仅有顺风向下的结构响应进行比较,给出比较结果。     

产品分馏塔风致开裂失效分析及横风向共振

使卡曼旋涡脱落的频率等于塔设备自身固有频率,以此来求解得塔设备发生横风向共振时的临界风速,确定产品分馏塔(位号:C-302)在强度计算时需要计入横风向载荷。经对该塔体上裂纹的开裂位置、裂纹处金相和断口等特点分析后,认定该塔所产生的裂纹为横风向作用下产生的疲劳开裂,并从塔设备的强度、结构、制造、现场施工等方面出发,提出抵抗横风向共振的措施。     

65m高钢制排气筒消除横风向风振分析

报道65m高钢制排气筒发生以及消除横风向风振的实例,对照有关标准对原设计进行分析,说明设计缺陷同发生横风向风振存在因果关系,总结发生及消除横风向风振的经验教训,为自立式钢烟囱的建造提供一个可供参考的案例。     

65m高钢制排气筒消除横风向风振简析

介绍某65 m高钢制排气筒发生以及消除横风向风振的实例,对照有关标准对原设计进行分析,总结排气筒发生及消除横风向风振的经验教训,可为自立式钢烟囱的建造提供一点借鉴。     

浅析TQ303-1精馏塔倾斜原因

塔器属于高耸结构。通过对TQ303-1精馏塔倾斜原因分析,对H/D>15且H>30m的自支承塔式容器进行横风向振动时的风力和风弯矩计算是很有必要的。     

烟气脱硫塔抗风设计的探讨

烟气脱硫是最近建设的比较多的装置,其目的是为了脱除再生烟气中的硫化物,氮化物以及粉尘颗粒等有害物质。冷却吸收塔为装置核心设备,具有总高度大,高径比大,塔内无压力,高耸钢烟囱段无内件,无平台等特点,为此对设备的这种结构必须在设计阶段特殊考虑。由于烟气脱硫塔总高度大,高径比大,所受横风向弯矩决定了塔体壁厚。如何减少横风向弯矩,国内标准仅仅给出了一些措施,但没有给出具体的计算方法。本文参考国外标准给出了塔体增加扰流片计算方法,并介绍了增加TMD降低横风向弯矩的方法。     

并排塔器的横风向激振特性与非光滑表面减振

随着化工设备集约化,并排塔器因大幅横风向振动而发生破坏的现象时常发生,然而各塔器间的耦合机制复杂,少有报道。为了解决这一问题,本文应用弹性支撑的刚性截断模型模拟并排塔器的横风向振动,开展了风洞实验,深入分析了并排塔器的横风向激振特性;设计了一种微型翅片,通过调整尺寸参数达到了最佳减振效果。研究结果表明,并排塔器的横风向激振可按照间距比范围分为三种典型振动状态,即单钝体模式、剪切层再附着模式和共同脱涡模式。当间距比S/D<2时,上游塔器在较小的折合流速下即发生驰振,且与下游塔器存在能量转化,在工程中应予以避免。当微型翅片的厚度参数大于0.1D及长度参数大于0.9D时,微型翅片的减振效果最佳,可以防止尾流驰振,使并排塔器的横风向振幅减小78.63%~95.67%。     

钢制排气筒顺风/横风向风振模拟与减振分析

以某一产生共振的钢制排气筒为例,利用ANSYS软件对排气筒进行顺风向与横风向的振动分析。通过采用调谐质量阻尼系统(TMD)与侧向弹簧阻尼支撑两种诱导振动减振方式,探讨了侧向支撑分布方式与参数对减振率的影响,并对两种减振方式进行对比。分析结果表明,横风向诱导振动对该排气筒的影响几乎达到顺风向的两倍,参数较优时TMD的减振率达到50%,侧向支撑采用对称布置时,减振率随刚度系数或阻尼系数的增加显著减小。     

高耸塔器风致振动的现场实测与疲劳分析

针对某一高度约为75m的精馏塔在检修时的风致振动进行了现场实测和疲劳计算分析。利用无线动态应变仪,结合随机减量法获得塔器的模态参数,利用高速静态应变仪测得塔器振动时的应力应变。结果表明,该精馏塔在检修状态下可以抵抗横风向共振引发的疲劳破坏。采用现场测试与标准相结合对塔器风致振动进行计算分析,可以较为准确地评估空塔或检修条件下塔器横风向振动可能引起的疲劳破坏,该研究方法可为塔器风致振动分析提供参考。     

烟气脱硫塔计算分析

对于高振型烟气脱硫塔,在设计过程中应进行横风向振动的分析、塔顶挠度的控制、采取一定的防振措施,尽量避免出现共振现象。设计出安全经济的烟气脱硫塔,保证装置的长期运行。     

COMPARISON OF METHODS OF ANALYSIS OF GYPSUM1

The different analytical methods proposed for the evaluation of gypsum have been subjected to an experimental test. A combination method, consisting of a fusion with KHCO₃ and determination of CaO by KMnO₄ titration, the SO₃ by Andrews method of titration of BaCrO₄ has been found to give very reliable results with the least consumption of time.     

氢气纯度分析方法准确性的探讨

ONACCURACYOFANALYSISOFOFHYDROGEN1前言我公司目前应用的氢气纯度分析方法有两种,一种是爆炸反应法,另一种是焦性没食子酸吸收法。几年来,人们对两种分析方法的准确性曾有过褒贬不一的评论。这里我们也谈谈自己粗浅的观点。2爆炸法测定氢气纯度一定量的氢气样品与适量的空气之均匀混合物因反应后生成液体水而引起气体体积减少,减少的体积等于参加反应气体体积之和。其中l／3为氧气,2／3为氢气。根据氢气取样量和反应前后混气体体积之差,以及氢气在反应中的体积比例关系,可计算出样品的氢气纯度。计算公式式中：A一混…     

HEASUREHENT OF INSTANTANEOUS RATES OF LOSS OF VOIATILE COMPOUNDS DURING DRYING OF DROPS

A novel technique serves to monitor instantaneous rates of loss of a volatile solute from a suspended drop during drying. A highly sensitive electron capture detector is used to monitor concentrations of SF6 released into a flowing gas stream from a suspended, drying drop. Simultaneously, the appearance and morphological development of the drop are monitored with a video camera. This provides the wherewithal of relating instantaneous rates of loss of the volatile solute to particular events during the development of particle morphology.

Initial experiments have been carried out with drops of aqueous solutions of glucose, sucrose, maltodextrin and coffee extract. The results clearly display the onset of the volatiles-retentive selective diffusion phenomenon. There is also substantial loss of the volatile component later in the drying process, when the drops undergo repeated ex ansion, bursting and cratering due to the formation of internaf bubbles. These experiments appear to be the first quantitative demonstration of major losses accompanying changes in drop morphology.     

SEDIMENTATION OF BINARY MIXTURES OF PARTICLES OF UNEQUAL DENSITIES AND OF DIFFERENT SIZES

A model is developed for the sedimentation from a suspension of two particle species of unequal densities and of different sizes. The composition and the thickness of various layers in the sediments are predicted using graphical and analytical methods. The model predictions were in excellent agreement with experimental results, when the particle size ratio was ≥ 108. When size ratio of the particles was 2.60 and 4.31 the agreement occurred in about 50 percent of the cases.     

茶多酚提取方法进展

本文综述了国内外现有茶多酚提取方法的现状以及近期的研究进展，并对其优缺点进行了评价。这将有助于中低档茶的综合利用和茶多酚的进一步开发应用。     

ANALYSIS OF RECENT MEASUREMENTS OF THE VISCOSITY OF GLASSES

Viscosity of Simple Soda-Silicate 500° to 1400°C Comparison of the results given by English with those of Washburn, Shelton and Libman, indicates a discrepancy in the absolute values of log₁₀ viscosity amounting to 0.6, those of Washburn et al., being relatively too high. If correction for this is made, the isothermal curves of log₁₀ viscosity as a function of soda content are smooth up to 50% Na₂O, showing no inflection. The observations as a function of temperature T are all represented within accidental error by an equation of the type where all three constants vary regularly with the composition. Change of Viscosity of Glass (6SiO₂, 2Na₂O) due to Molecular Substitution of CaO, MgO and Al₂O₃ for Na₂O The effect is clearly brought out by plotting (from the results of English) the change of log₁₀η due to the substitution as a function of temperature. The curves each show a sharp bend at a temperature between 840° and 1050°C, which is designated the aggregation temperature T_a. If we divide these curves by the corresponding percentage substituted, we get curves for each oxide which are straight and parallel below the aggregation temperatures, the slopes (increase of change of log₁₀η per 100°C) being −0.056 (CaO), −0.055 (MgO), −0.018 (A1₂O₃) per per cent oxide substituted. For substitution of 1/2 molecule the slopes are −0.325 (CaO), −0.23 (MgO) and −0.18 (Al₂O₃) per 100°. At the aggregation temperature the change of log₁₀η per per cent is a minimum, 0.03 to 0.06 for CaO, 0.12 for MgO, 0.07 for Al₂O₃. Evidence of Aggregation in Glasses, from viscosity Measurements The sharp bends in the plots of change of log₁₀η due to substitution of an oxide for Na₂O, suggest the beginning of molecular aggregation at these temperatures. These aggregation temperatures are close to the devitrification temperatures, but the effect on the viscosity curves cannot be due to actual devitrification since it does not change with time. Taking the aggregation temperatures as equal to devitrification temperatures, additional isotherms are roughly sketched into the equilibrium triangle of the system Na₂O-CaO-SiO₂. Change of Viscosity of Glass (4SiO₂, 2Na₂O) due to of Substitution of B₂O₃ for SiO₂ The change of log₁₀η (from the results of English) is plotted as a function of temperature, and also the change of log₁₀η per per cent B₂O₃. The curves are more complex than for the substitution for Na₂O.     

环氧树脂羟基值测定方法的研究

利用乙酸酐、吡啶和浓硫酸混合的乙酰化试剂测定环氧树脂中羟基值含量的方法具有操作简便、滴定终点明显和分析结果误差小等优点。     

骑式摩托车油箱喷涂工艺的改进

面对日益激烈的市场竞争,摩托车油箱外观质量越来越成为影响销售的因素之一。文章介绍了改进工艺后的油箱涂装,该涂装体系提高了油箱外观的丰满度,降低了油箱涂装的生产成本。     

几种针状焦性能对比

针状焦分石油系和煤系两大类,这主要取决于针状焦的原料来源。在同一系列中由于原料不同和工艺条件不同 ,针状焦的各自性能也不相同。针状焦是生产超高功率石墨电极和高功率石墨电极的主要原料 ,针状焦的性能对石墨电极的质量有至关重要的影响。所以对针状焦性能以及其对石墨电极质量影响的研究十分必要的。以下是常用的几种进口针状焦和国产针状焦的性能对比。１原料性能分析对比原料试样包括４种针状焦 ,其中两种为进口针状焦：三菱针状焦和新日化针状焦;另两种为国产针状焦：鞍山针状焦和锦州针状焦。其中除锦州针状焦是石油系针状焦外…     

用两个形状指数表征粉煤灰颗粒形貌的研究

引用两个形状指数表征颗粒形状的概念,即先将颗粒形状近似为椭圆,再将椭圆图像分离:以圆为基准的颗粒宏观形状指数δ;以光滑椭圆为基准的颗粒轮廓凹凸度,即微观形状指数ζ。分析和发展了近似椭圆模型。并运用图像分析仪对粉煤灰、水泥样品进行实验。结果表明,粉煤灰颗粒的两个形状指数δ和ζ都大于水泥颗粒。证明粉煤灰颗粒的球形度、表面光滑度优于水泥,而且,随着粒径增大,δ和ζ呈下降趋势,表明磨制颗粒越粗。(?)粒形状越不规则。文中还运用近似椭圆模型再现了颗粒的模拟图像。