聚乙烯塑料管材中再生塑料的定量分析

借助傅立叶红外光谱仪和差示扫描量热仪,对聚乙烯塑料管材中的聚乙烯再生塑料进行定量分析。结果表明,利用梯度等温结晶法制备样品,分析管材样品DSC曲线的多重熔融峰,可以实现对聚乙烯管材中聚乙烯再生塑料的准确定量计算。     

梯度等温结晶法鉴别燃气管用PE树脂

通过等速降温结晶和梯度等温结晶两种方法对国内市场的几种主要燃气管用聚乙烯树脂进行DSC测试.结果表明,采用梯度等温结晶制得的样品DSC熔融曲线有多重熔融峰,测试结果重复性好,不同样品间测试区分度高,可以实现对未知燃气管材材质归属的快速判定.     

PE100压力管道材质分析方法的研究

使用红外光谱仪(FT-IR)、广角X-射线衍射仪(WAXD)、核磁共振仪(NMR)、示差扫描量热仪(DSC),分别详细研究了PE100与其它聚合物的图谱差别,建立了一套准确的测定聚乙烯压力管道材质的方法.     

粉末压片-X射线荧光光谱法快速测定生石灰粉中氧化钙和二氧化硅

采用粉末压片法制样,建立了波长色散X射线荧光光谱法快速测定生石灰粉中氧化钙、二氧化硅的分析方法。由于没有国家标准样品,采用自制生石灰粉标准样品绘制工作曲线。考察了样品粒度及吸潮对分析结果的影响。实验表明,在样品粒度为74μm、压样机压力为12 MPa、压制时间为45s的制样条件下荧光计数率最稳定,在30min内测定样品效果最佳。采用α理论系数法和经验系数法相结合校正基体影响。对同一生石灰粉样品进行精密度实验,各组分的相对标准偏差(RSD,n=11)在0.04%~0.43%。测定了5个生石灰粉样品,所得结果与常规化学分析方法测定值相符。     

差示扫描量热法(DSC)测定全密度聚乙烯结晶度

本文自建了用差示扫描量热仪测定全密度聚乙烯的熔融温度、结晶温度、结晶度等指标参数的分析方法,讨论了测定过程中热历史、样品制备、升温速率等因素对测试结果的影响;并对某乙烯厂的多批次全密度聚乙烯进行了测试,通过重复性试验,表明该方法具有准确、简便、快速的技术特点。     

管材用硅烷交联聚乙烯的研制

利用反应挤出原理在双螺杆挤出机上进行硅烷交联聚乙烯的研制，筛选出HDPE－1、HDPE－2和LLDPE－3等3种聚乙烯共混料作为硅烷交联聚乙烯的基料，使接枝料具有高的流动性，交联料具有高的交联度、力学性能和耐热性能；研制的DMGL－01和DMGL－02两种硅烷交联聚乙烯专用料，经实际使用证明其性能指标达到或超过了CJ／T 108－1999要求，可以应用于交联聚乙烯铝塑复合管和交联聚乙烯管的生产。     

MPD复合卷材全天候防水成套施工工法研究

针对防水工程中的难题,提出了聚乙烯涤纶复合卷材全天候防水成套施工工法,指出此工法关键技术在于采用线性低密度聚乙烯高分子复合卷材和聚合物水泥防水胶粘料。研究结果表明,MPD防水施工工法成熟、可靠、经济,是建筑防水工程的突破,具备在全国地区推广应用的条件。     

聚乙烯承压管道的发展和原料选择

自从20世纪60年代英国燃气公司首次使用聚乙烯(PE)材料做燃气管以来.聚乙烯承压管道以其质量轻、优良的耐腐蚀和耐化学性、耐低温性、耐应力开裂性、可挠性、可熔融焊接,易于运输和安装以及良好的抗地震性能等优点在全球范围得到了迅速推广和应用。 国际上对压力管材用聚乙烯材料一直进行着不断的研究和改进,尤其是1988年Slovy公司研制出PE100管材专用料以来,聚乙烯管的许用应力大     

苏联贮仓结构计算中若干理论问题

贮仓结构受力取决于贮存散料的压力分布与计算,它乃属散体静力学的范畴。1895年杨森根据每一个平面中垂直压力是均布的假设,解决了散科对贮仓底和壁上所受压力的测定。它迄今仍为贮仓计算散料压力的经典理论。 嗣后С.Г.塔赫塔满谢夫等才发现散料压     

电位滴定法测定有机—无机复混肥料中的氯离子方法探讨

本文建立了测定有机—无机复混肥料中氯离子的电位滴定法,样品的相对标准偏差为1.1%~0.3%,回收率为96.6%~99.1%,本法相对国家标准中有机—无机复混肥料中氯离子的测定方法而言操作简便、快速、准确度高。     

Effects of temperature shock treatments on the stability of anaerobic digesters operated on separated cattle slurry

Using laboratory-scale daily fed digesters operating at steady-state on separated cattle slurry, the temperature was lowered in a similar manner to that which might be expected on a farm due to heating failure; three different recovery methods were then tested. Raising the operating temperature from 3–6°C to 35°C in a single day had only a transient effect on digester stability. Steady-state conditions were re-established within 8 days of the temperature rise when a 25-day retention time was employed and within 6 days at 10-day retention time. However, slowly raising the operating temperature (over several days) had a more deleterious effect on digester stability. When a 25-day retention time was employed 10 days were required from the initial temperature rise before steady-state conditions were re-established, whilst at a 10-day retention time the period was greater than 12 days. It is therefore proposed that the digester temperature should be raised back up to the normal operating temperature as soon as possible after a heating failure. Digesters which were not fed during the recovery period showed a rapid removal of potentially toxic volatile fatty acids, and this procedure is recommended in the period following temperature shock.The main indicator of digester instability was a dramatic but unequal rise in the concentration of the individual volatile fatty acids. An order of sensitivity to the temperature shock treatment was established: i-butyrate i-valerate i-caproate > propionate > n-valerate n-caproate > acetate n-butyrate. Those to the left accumulated most rapidly in the temperature stressed digester, and were removed least quickly during the recovery period. Thus the bacteria responsible for the breakdown of the higher volatile fatty acids (presumably the obligate proton-reducing bacteria) were more sensitive to the shock treatment applied than those catabolising acetate (presumably the acetate-utilizing methanogenic bacteria).The concentration of the branched volatile fatty acids and propionic acid were the most sensitive to the temperature shock treatment, and therefore represent more sensitive monitors of digester stability than acetic acid or the total volatile fatty acid concentration.     

煤系高岭土合成莫来石的研究

本文分别用煤系高岭土直接合成M45莫来石和通过添加工业氧化铝合成M60莫来石,并采用DSC/TGA、XRD和SEM等测试手段对试样进行了表征。结果表明：烧结温度为1 500℃、恒温时间超过3h的条件下,合成莫来石的主要组分符合我国《烧结莫来石》（YB/T5267-2005）标准要求。     

Quantitative real-time PCR analysis of total and propidium monoazide-resistant fecal indicator bacteria in wastewater

A real-time quantitative PCR (qPCR) method and a modification of this method incorporating pretreatment of samples with propidium monoazide (PMA) were evaluated for respective analyses of total and presumptively viable Enterococcus and Bacteroidales fecal indicator bacteria. These methods were used in the analyses of wastewater samples to investigate their feasibility as alternatives to current fecal indicator bacteria culture methods for predicting the efficiency of viral pathogen removal by standard treatment processes. PMA treatment was effective in preventing qPCR detection of target sequences from non-viable cells. Concentrates of small volume, secondary-treated wastewater samples, collected from a publicly owned treatment works (POTW) under normal operating conditions, had little influence on this effectiveness. Higher levels of total suspended solids, such as those associated with normal primary treatment and all treatment stages during storm flow events, appeared to interfere with PMA effectiveness under the sample preparation conditions employed. During normal operating conditions at three different POTWs, greater reductions were observed in PMA-qPCR detectable target sequences of both Enterococcus and Bacteroidales than in total qPCR detectable sequences. These reductions were not as great as those observed for cultivable fecal indicator bacteria in response to wastewater disinfection. Reductions of PMA-qPCR as well as total qPCR detectable target sequences from enterococci and, to a lesser extent, Bacteroidales correlated well with reductions in infectious viruses during both normal and storm flow operating conditions and therefore may have predictive value in determining the efficiency at which these pathogens are removed.     

Part load performance of air-cooled centrifugal chillers with variable speed condenser fan control

Air-cooled centrifugal chillers are commonly used in commercial buildings but their performance analysis is lacking. This paper investigates the part load performance of the chillers via a thermodynamic model. The model was validated using a wide range of operating data from an existing chiller with specific settings of outdoor temperature and condensing pressure in controlling the condensing temperature. The validated model was developed specifically to ascertain the maximum coefficient of performance of chiller (COP) together with the strategy for optimizing the condensing temperature under various operating conditions. It is found that the highest COP occurs at a part load ratio (PLR) of 0.71–0.84, depending on the outdoor temperature and the control of condensing temperature, rather than at full load. Yet the chillers operating at such part load conditions will cause extra energy used for the early staging of chilled water pumps. To minimize the overall chiller plant energy consumption, it is still preferable to implement chiller sequencing based on the full load condition than on the aforementioned PLRs. The results of this paper present criteria for implementing low-energy strategies for operating air-cooled chillers satisfying a given building cooling load profile.     

不同方法测得热固性树脂耐热性能的分析

运用热变形温度(HDT)、示差扫描量热(DSC)和动态热机械分析(DMA)方法对不同热固性树脂固化体系的耐热性能进行了测试,并分析了测试结果差异与其物理机制的关系。结果表明:通过DMA图谱中模量曲线拐点得到的热固性树脂耐热温度,与材料的热变形温度比较吻合。从DMA图谱中得到的玻璃化转变温度比DSC曲线得到的稍低。     

Shear strength evaluation of composite pavement with geotextile as reinforcement at the interface

This research was conducted to investigate the shear strength at the interface between polymer concrete and asphalt concrete with geotextile as reinforcement at the interface of these two types of concrete. The samples were tested for the parameters of different surface conditions [rough and smooth], curing types [room and thermal curing], temperature effect and the impact of geotextile as reinforcement. To investigate the correlation between these parameters, four different testing conditions were implemented. The results showed a significant improvement of shear strength for rough surface sample as compared to smooth surface sample. Moreover, samples cured in oven had lower shear strength as compared to samples cured in room condition. Besides that, high temperature has an adverse impact on the shear strength at the interface between polymer concrete and asphalt concrete due to the weakening of asphalt concrete at high temperature. As for samples reinforced with geotextile, the shear strength resistance was better as compared to unreinforced samples. Through visual observation, the types of failure under all testing conditions were mixed failure mode.     

空气源热泵热水机组变工况运行的实验研究

本文对空气源热泵热水机组进行了大范围变工况的实验研究，得出了机组制热量、输入功率、性能系数、排气压力、排气温度、吸气压力、吸气温度等参数随环境温度的变化关系，而后分析了工况变化对空气源热泵热水机组及压缩机的影响，以及机组在不利条件下工作出现的问题，最后针对这些问题提出了解决方法，为提高机组的性能和运行可靠性提供了重要参考。     

办公建筑中吊顶辐射空调系统夏季工况性能测试研究

以办公建筑中实际使用的一套金属吊顶辐射板+新风的空调系统为研究对象,对夏季运行工况进行了测试研究。分别对比分析了高温和高湿气象条件下办公建筑室内的温湿度分布,比较了不同高度和不同位置处的温湿度场,在测试条件下,室内有良好的热舒适性。     

小扰动工况下天车驾驶室空调系统特性实验研究

针对天车在具有高温集中热源的车间中运行环境的变化,搭建了天车驾驶室空调系统的实验装置,设置符合实际情况的小扰动运行工况进行了实验,综合分析了运行环境和运行方式的改变对天车驾驶室空调系统制冷量和能耗的影响。     

双轴拉伸聚合物膜片成型过程温度场研究

建立了聚合物膜片在成型过程中温度场的数学模型，并研究了各工艺操作参数对温度分布的影响．在对生产厚规格薄膜的各种工艺条件考察后，提出了改进操作的建议．