膨胀型防火涂层“新-老”涂层体系的热阻

在既有老化涂层上涂覆新涂层形成“新-老”复合涂层体系,复合涂层的热阻并非既有涂层热阻与补涂涂层热阻的简单叠加.基于隔热性能试验的温度测量结果,计算复合涂层体系的等效热阻常数,通过对不同试件等效热阻常数的对比分析,考察补涂涂层对既有涂层和复合涂层热阻的影响规律.结果表明:既有涂层热阻随补涂涂层厚度增加而降低,当补涂涂层厚度大于1.0 mm时,既有涂层热阻的贡献率不超过20%,计算复合涂层热阻时可忽略不计;当补涂涂层厚度较薄(0.5 mm)且既有涂层老化时间较短(≤21循环),或既有涂层有面漆时,建议考虑既有涂层热阻的贡献(贡献率>20%).当补涂涂层与既有涂层类型不同时,复合涂层体系的热阻更大,隔热性能更好.

层状地基土水平抗力比例系数反演的杂交粒子群算法

土的水平抗力比例系数是基坑支护结构变形计算的重要参数,针对层状地基土中水平抗力比例系数反演的多目标优化问题,结合支护结构水平位移实测值和杆系有限元法,提出基于粒子群算法(PSO)的层状地基土水平抗力比例系数反分析法。给出水平抗力比例系数和目标函数精度双控的反演计算收敛条件和水平抗力比例系数最优解稳定条件。在利用基坑工程数值模型验证反演参数准确性基础上,运用工程实例进一步验证杂交粒子群算法(breedPSO)在水平抗力比例系数反演计算中的适用性。对比分析优化方法的计算效率和反演参数的收敛特性。结果表明:杂交粒子群算法具有更高的计算效率和计算精度,为合理反演水平抗力比例系数提供了有效途径。

大容量多层陶瓷电容器的充测特性与测试方法研究

智能驾驶时代的到来使得新能源汽车得到了巨大发展,大容量、高耐压、多层陶瓷电容的市场需求与日俱增。这类电容属于Ⅱ类陶瓷电容,具有介电常数大、充放电时间长的特点,测试分选这类电容需提出更高要求。为满足这类电容的测试分选需求,为相关行业研发人员解惑,分析了电容的介电特性、吸收电特性、充放电特性、双峰现象以及在线测试等。通过相关产品测试得出:在额定电压电流条件下,改变充电时间、充电次数、空位间隔等相关参数,可延长充电时间和充电后空置时间,减小漏电流。

恒定功率与恒温热板对粉尘层着火温度的影响

对粉尘层着火温度测试系统进行改装,试验研究了恒定功率与恒温热板条件下静电喷涂粉末的粉尘层着火温度变化规律,可为粉尘层的着火危险性评估及可燃性粉尘环境用防爆设备的选型提供技术支持。

Effective dielectric constant model of electromagnetic backscattering from stratified air–sea surface film–sea water medium

Studies of surface film medium on the sea surface are carried out in this paper for developing the technology to automatically detect and classify sea surface films, and an effective dielectric constant model of electromagnetic backscattering from a stratified air–ocean interface. Numerical results of the new model show the characteristics of effective dielectric constants for the air–sea surface film–sea water medium as follows. The effective dielectric constants decrease with increasing relative dielectric constants of the sea surface films. The effective dielectric constants decrease in horizontal polarization（abbr. HH polarization） and increase in VV vertical polarization（abbr. VV polarization） with increasing radar incident angle. Effective dielectric constants vary with relative sea surface film thickness as a cosinusoidal function of sea surface film thickness. Effective dielectric constant of VV polarization is larger than that of HH polarization. Two potential applications are found with our model, i.e., the retrieval of dielectric constants from the sea surface film, and the film thickness retrieval with our model. Our model has a highly significant influence on improving the technology related to the remote sensing of sea surface films.

Identification of Phases in Aluminide Coatings by Means of Interference Layer Metallography

Interference layer metallography was used to identify the phases present in the aluminide coating on superalloy IN738LC. They are: two intermetallic aluminides NiAl and Ni_3Al, y-solid solution and a Cr-rich solid solution, two sulphides M_(23)C_6 and MC, and two sulphides (Al,Cr)_3S_4 and (Cr,Ti)_3S_4. ZnS and ZnSe are proposed to be vapor deposited onto the surface of the specimen to get good colour contrast and good light-dark contrast. The refractive index and absorption coefficient of all these phases have been detemined.

Application of a nondestructive method to evaluate the active layer in a cold region

To provide a safe transportation system in an extremely cold region,evaluation needs to be conducted of the thickness and the volumetric water content of the active layer,as they significantly affect frost heave.The objective of this study was to evaluate the dielectric constant(κ)of the active layer using ground-penetrating radar(GPR)and a dynamic cone penetrometer(DCP);this evaluation was then used to estimate the thickness and the volumetric water content of the active layer.A field located in midwest Alaska was selected as the study site.A GPR survey and two DCP tests were conducted on the surface of the ground,and the ground temperature was measured.From the GPR survey,travel times of the electromagnetic wave in the active layer were obtained.In addition,the thickness of the active layer was determined by using the dynamic cone penetration index(DCPI)and ground temperature.By using the travel time and travel distance of the electromagnetic wave in the active layer,dielectric constants were calculated as 26.3 and 26.4 for two DCP points.From the mean dielectric constant,the volumetric water content was estimated to be 40%~43%,and the thickness of the active layer was evaluated along the GPR survey line.The spatial-scaled GPR image showed that the thickness of the active layer varied from 520 mm to 700 mm due to the presence of a puddle,which accelerated the heat exchange.The results show that evaluation of the dielectric constant using the GPR survey and the DCP test can be effectively used to estimate the thickness and the volumetric water content of the active layer.

Influences of different structures on the characteristics of H_2O-based and O_3-based La_xAl_yO films deposited by atomic layer deposition

H_2O-based and O_3-based La_xAl_yO nanolaminate films were deposited on Si substrates by atomic layer deposition（ALD）. Structures and performances of the films were changed by different barrier layers. The effects of different structures on the electrical characteristics and physical properties of the La_xAl_yO films were studied. Chemical bonds in the La_xAl_yO films grown with different structures and different oxidants were also investigated with x-ray photoelectron spectroscopy（XPS）. The preliminary testing results indicate that the La_xAl_yO films with different structures and different oxidants show different characteristics, including dielectric constant, equivalent oxide thickness（EOT）, electrical properties, and stability.

Effects of GaN cap layer thickness on an AlN/GaN heterostructure

In this study, we investigate the effects of Ga N cap layer thickness on the two-dimensional electron gas（2DEG）electron density and 2DEG electron mobility of Al N/Ga N heterostructures by using the temperature-dependent Hall measurement and theoretical fitting method. The results of our analysis clearly indicate that the Ga N cap layer thickness of an Al N/Ga N heterostructure has influences on the 2DEG electron density and the electron mobility. For the Al N/Ga N heterostructures with a 3-nm Al N barrier layer, the optimized thickness of the Ga N cap layer is around 4 nm and the strained a-axis lattice constant of the Al N barrier layer is less than that of Ga N.

Proposal for a cross layer scheme for real-time wireless video

This paper focuses on the design of the cross layer between the video application layer and the MIMO physical layer. MIMO physical layer research has promised an enormous increase in the capacity of wireless communication systems. Also MIMO wireless systems operate under fading conditions where the channel faces arbitrary fluctuations. Since the wireless channel changes over each coherence period, the capacity of the wireless channel, given the power constraints, changes. Hence to make efficient use of the available capacity one needs to adapt the video bit rate. However it is impossible to adapt at the application layer as changing the parameters of the video takes more time than the coherence period of the channel. In this paper we address this problem through a novel solution and also investigate its performance through a simulation study.

Separation of Amino Acids Based on Thin-Layer Chromatography by a Novel Quinazoline Based Anti-Microbial Agent

A newly designed quinazoline based compound, 6-pyridin-2-yl-5,6-dihydro-benzo[4,5]imidazo[1,2-c] quinazoline (PDBIQ) has shown the ability for the easy detection of nineteen amino acids on thin-layer chromatography plates as a spray reagent. This new reagent enabled to produce various distinguishable colors with amino acids with different RF values. The detection limits and the binding ability of PDBIQ with amino acids have been calculated. PDBIQ is also able to detect aminoacids from hydrolised seed protein. The title compound also exhibited profound inhibitory action against some gm (+ve) and gm (-ve) bacterial organisms. This paper deals with synthesis, spectroscopic application and biological evaluation of the organic moity.

聚合物类型、注液方式和层系组合方式对聚驱效果的影响实验

目前大庆油田聚合物驱油技术的应用对象已经由一类储层向二、三类储层转移,原注入体系在注聚初期阶段的适应性较差,对高渗层的封堵能力弱,需要进一步评价注入体系和优化注入方式,以提高聚驱效果。因此开展了聚合物类型、注液方式和层系组合方式对聚驱效果影响实验研究。结果表明:实验所用“抗盐”聚合物低剪切强度表现为内摩擦力即视黏度损失较小,但高剪切强度条件下结构易于破坏,致使黏度保留率较低、滞留和液流转向能力较差;考虑到矿场注入压力受到储层岩石破裂压力限制,与“恒速”注入方式相比较,“恒速/恒压”注入方式和现场注入方式更为贴近;采用“分步注入”,模型中“层内非均质”岩心打开时机较晚,最终采收率增幅较大。实验结果可以为矿场局部注聚技术的推广提供技术支持。

多层常梯度声速剖面的测深误差改正方法

声速剖面(SVP)是多波束测深重要参数。为提高观测数据质量,在复杂水域地带往往通过声速剖面加密观测法或数据内插法,但始终会产生不同程度的折射误差。本文通过分析声速对测深系统的影响和构建常梯度等效声速模型进行了推导,提出了常梯度声速剖面改正模型,较好地解决了声速代替误差或声速剖面不准确带来的影响。试验结果表明,该模型后处理解析的地形边缘数据具有更好的一致性,定量成果优于传统声速剖面改正算法。

煤层气井两层合采气水同产井底流压计算方法

井底流压是确定煤层气井合理工作制度,进而实现长期稳产的关键影响因素。针对定质量模型不考虑储集层段加速度压降和不同井段质量变化导致不符合两层合采特性,以及采用下部储集层井底流压作为2个储集层井底流压来调节生产制度导致不符合上部储集层调节需求的问题,对加速度压降表达式进行了分解和推导,建立了其与单位长度径向流量的关系式,推导了含径向流入的储集层段压降公式;将储集层分成多个微元段,建立了每个微元段的压降计算方法;根据各井段气水流量,推导了相应的气相和水相速度计算方程;将上述方程结合,建立了变质量模型。将生产数据分别代入变质量模型和定质量模型,气水同产时,变质量模型的误差为2.96%~6.67%,定质量模型的误差为7.33%~15.10%,变质量模型更加准确。2个储集层的井底流压相差较大,最大相差47.3%,因此需要根据各自的井底流压调节生产制度。变质量模型能够准确给出合采各层的井底流压,更符合现场实际,同时也避免了采用相同井底流压导致无法精准调节2个储集层生产制度的问题,从而为制定最优化排采制度、实现高产稳产提供技术支撑。

风廓线雷达资料在聊城霾天气过程分析中的应用

【目的】通过分析CLC-11-D型边界层风廓线雷达资料,以期提高环境气象预报水平。【方法】统计2015—2020年霾天气过程中的大气边界层高度和风场特征。【结果】霾日数年平均为62d,呈逐年减少趋势;霾在冬季发生最多,其次是春季,冬春季霾日数占全年霾日数的82.1%;地面~1000 m大气层霾出现的概率随风速增大而减小,风速≤6 m·s^(-1)最有利于霾的形成、维持和发展,6m·s^(-1)<风速≤8 m·s^(-1)时霾减弱,风速>8 m·s^(-1)有利于霾的消散;1000~1500 m大气层风速≤8 m·s^(-1)最有利于霾的形成、维持和发展;1500~2100 m大气层2.1m·s^(-1)<风速≤6m·s^(-1)最有利于霾的形成、维持和发展;2100~3000 m大气层4.1 m·s^(-1)<风速≤8 m·s^(-1)最有利于霾的形成、维持和发展;地面~1500 m大气层霾出现时风向没有明显的规律,1500 m以上大气层西北风、西风最有利于霾的生成;925 hPa和850 hPa天气系统演变对霾天气的生成、发展、维持和消散具有指示意义。【结论】风廓线雷达在分析聊城霾天气过程中有重要应用,其资料特征可为环境天气预报预警和研究提供参考依据。

含恒功率负荷的直流微电网储能变换器双层模糊控制方法

控制储能变换器能够避免直流微电网的储能单元出现过充和过放的问题,为了提高直流微电网在运行中的稳定性,提出一种含恒功率负荷的直流微电网储能变换器双层模糊控制方法。通过构建储能变换器的平均开关模型,得到直流微电网中含恒功率负荷的等效电路图,构建等效电路的微分方程,当微分状态方程逐渐收敛到平衡点时,判断直流微电网的运行状态,分析含恒功率负荷的储能变换器对直流微电网的影响。利用第一层模糊控制器调节直流微电网中储能变换器的SOC,利用第二层模糊控制器改善第一层模糊控制器在功率校正过程中出现的真实负载与负荷调度曲线偏离的问题,经过双层模糊控制,得到储能变换器的功率指令,实现储能变换器的双层模糊控制。实验结果表明,文中方法能够防止光伏电源输出功率与负荷消耗功率之间发生突变,从而避免蓄电池的初始SOC值较低而提前退出供电,提高直流微电网运行的稳定性。

华东沿海地带台风风廓线特征的观测个例分析

利用2007年的"韦帕"、2009年的"莫拉克"、2010年的"凡亚比"和2011年的"梅花"四个台风的GPS探空数据,本文对华东近海和沿海地带的台风风廓线特征进行分析。首先求出梯度风速及其对应的高度,在此基础上利用指数律和对数律对风廓线进行拟合,并对幂指数、10米高度的地表风速和梯度风速的风速比,以及由对数律定义的常通量层高度等参数进行计算,并对梯度风高度和常通量层高度进行比较。结果表明:登陆台风沿海地带风廓线的梯度风高度和常通量层高度有明显差异。本文还对登陆台风平均风廓线的各参数进行了计算,并对梯度风高度以下风廓线偏离对数律的原因进行了讨论。

随环境变化的土壤热波动特性研究

根据周期性变化的环境温度和土壤半无限大平壁假设,建立了土壤导热数学模型,并采用PHOENICS3.6软件求解,得出了不同温度波对土壤导热区域的影响。研究了不同频率、振幅的热波及不同物性参数的土壤对不同深度处热波响应特性的影响。指出该研究方法可以应用于冷热油交替输送管道的非稳态温度场研究。

一种大规模粮堆介电常数测量方法

针对大规模粮堆的水分检测问题,提出利用表层穿透雷达技术,通过大范围测定粮堆内部介电常数空间分布,再利用介电-水分模型间接推算水分含量的方法.提出基于反射和折射定律,通过逐层反演的方法推算粮堆各层介电常数的方法,通过利用测井法获取的精确测量结果,反推出逐层反演法所需的校准系数,从而极大地提高逐层反演法的精度.实验结果表明,修正系数后的逐层反演法所推算的介电常数与测井法相比误差很小,能够满足实际应用要求,从而为粮堆大规模水分含量测量奠定了基础.