超声波均匀沉淀法制备Y2O3∶Eu3＋纳米晶及其荧光性能

在超声波作用下,使用均匀沉淀法制备了纳米Y2O3:Eu3+荧光粉,考察反应物配比、溶液pH值、反应时间、煅烧温度等制备条件对产物品粒尺寸及产率的影响.利用X射线粉末衍射(XRD)、等离子体原子发射光谱(ICP-AES)、透射电镜(TEM)和荧光光谱等测试手段表征产物,结果表明,该法制得的纳米Y2O3:Eu3+荧光粉颗粒为球形,粒度分布均匀,平均粒径约为30 nm.与微米晶相比,该纳米晶的激发光谱发生明显红移,电荷迁移态最大值(CTS)红移12 nm,发射光谱中发射主峰蓝移8 nm.     

周期性浸泡下三峡库区松散土体微观特性分析

三峡库区水位上升至175 m之后引发了新的地质灾害,尤其是引起了已发地质灾害的复发。已有研究未考虑周期性浸泡对三峡库区土体性质的影响。采取三峡库区典型松散土体,运用多晶X射线衍射仪对所采取的岩土样在天然状态、长期性浸泡状态、周期性浸泡状态试验工况下的物相进行定性、定量分析的物相变化,得出库区水位升降引起的周期性浸泡作用是导致土体结构和强度劣化的重要因素。     

超声波均匀沉淀法制备Y2O3∶Eu3＋纳米晶及其荧光性能

在超声波作用下,使用均匀沉淀法制备了纳米Y2O3∶Eu3＋荧光粉,考察反应物配比、溶液pH值、反应时间、煅烧温度等制备条件对产物晶粒尺寸及产率的影响.利用X射线粉末衍射（XRD）、等离子体原子发射光谱（ICP-AES）、透射电镜（TEM）和荧光光谱等测试手段表征产物,结果表明,该法制得的纳米Y2O3∶Eu3＋荧光粉颗粒为球形,粒度分布均匀,平均粒径约为30 nm.与微米晶相比,该纳米晶的激发光谱发生明显红移,电荷迁移态最大值（CTS）红移12 nm,发射光谱中发射主峰蓝移8 nm.     

Analysis of Key Factors in Cable Force Calculation for Cable-Stayed Bridges

Three methods for calculating cable force (analytic method, fitting method and finite element method) are analyzed and compared. The effects of boundary condition, spectrum resolution, sampling time, and number of sampling points on the precision of cable force identification are discussed, and error analysis is conducted. The results of three methods applied to a practical project are significantly less than the design value. Comparatively, the result of finite element method is the closest to the design value. Moreover, their computational precision and error are compared and analyzed. The precision of frequency identification of cables, long cables in particular, is strongly affected by frequency resolution. If the frequency resolution is included in calculating the cable force, the identification error can be reduced greatly.     

A dual measurement method of strain and temperature

With the rapid development of China's foreign trade, the coastal and inland waterway transport has been increased rapidly. The potential market for marine engines is more and more obvious. The measurement of the engine temperature and strain becomes very important. The fluorescence fiber sensors are broadly used to measure temperature, concentration, and pH value, etc. The fluorescence sensing systems are based on different principles, namely fluorescence intensity, fluorescence intensity ratio, and fluorescence lifetime. The fluorescence lifetime is an effective parameter for sensing purpose, because it is independent of the intensity of the pumping source and does not need expensive narrow-band filters. An experiment system has been established, in which some samples were produced to measure the fluorescence lifetime and temperature characteristics and the relationship of the strain and temperature versus the fluorescence lifetime was achieved at the same time. The experiment result was fitted and analyzed. The test results show that the fluorescence lifetime decreases with the increasing of temperature. The change of fluorescence lifetime with the strain is inconspicuous comparing to that with the temperature.     

浅谈船舶液压系统的油液监测分析

本文简述了液压油的污染物来源及对液压设备的影响,并基于油液监测技术的基本原理及监测方法,列举了油液监测技术在液压系统故障诊断研究中应用的案例,为船舶液压设备的维护和维修提供了依据。     

六氟化钨中氟化氢的分析方法研究

本文依据六氟化钨和氟化氢的特殊性质,建立了利用傅立叶红外光谱法分析六氟化钨中的氟化氢的分析方法。氟化氢有八个特征吸收峰,为了尽量避免水蒸气的干扰,本文选取4038.2cm-1处的吸收峰作为氟化氢的特征吸收峰,并通过对不同浓度的氟化氢标准气体的分析建立了氟化氢浓度与其特征吸收峰的吸光度相对应的标准曲线。最后通过分析六氟化钨中氟化氢特征吸收峰的吸光度大小,在标准曲线上查得氟化氢的浓度,即可以得到六氟化钨样品中氟化氢的含量,从而建立了六氟化钨中氟化氢的分析方法。     

路用环氧沥青固化反应动力学研究

利用非等温式差示扫描量热法(DSC)和傅里叶红外光谱分析方法(FTIR)对路用环氧沥青的固化机理进行了研究。根据不同升温速率下路用环氧沥青固化反应的DSC曲线,基于热分析动力学的方法,确定固化反应动力学参数,利用非线性回归建立了路用环氧沥青固化反应方程,进一步通过红外光谱分析方法验证固化反应方程的合理性和准确性。根据上述反应方程推算出不同温度条件下路用环氧沥青的固化程度和固化时间,从而为基于环氧沥青的长寿命沥青路面施工工艺及交通开放时间的确定提供参考依据。     

SP彩色压花荧光路面施工技术

SP彩色压花荧光路面施工技术通过将SP彩色涂料喷涂于沥青表面,改变了传统沥青的黑色表面,使路面更加美观;通过沥青压花工艺,在沥青路面路口及边缘印出各种图案,既增加了道路防滑性,又使道路更具提示性和美观性;通过将荧光材料填充于预留图案中,白天兼顾装饰美观作用,夜间发出彩色荧光,大大提高了观赏性和道路行驶安全性。本文对SP彩色压花荧光路面施工技术的工艺流程及操作要点进行了阐述,可对该技术的推广应用起到一定的借鉴作用。