PBA－g－AS共聚物的合成

本文以交联ＰＢＡ为主链，ｇｒ和ＡＮ为接技单体，通过乳液接枝共聚会成了ＰＢＡ－ｇ－ＡＳ井聚物．研究了乳化剂加入量、引发剂种类及用量、单体加入方式及单体浓度、反应时间以及ＰＢＡ胶乳性质等对接枝率、转化率及粒子形态的影响，同时也研究了ＴＤＭ用量对接枝链分子量及接枝率的影响．     

换热管直径对换热器(火用)效率影响的探讨

本文通过换热管直径对换热器(火用)效率影响的分析,提出了换热器设计及改造时,减小(火用)损失的一条途径.     

Development of an index based on fish,macroinvertebrates, phytoplankton,and physicochemical properties to assess urban aquatic ecosystems in Jinan,China

Because of the rapid growth in urbanization over recent decades, urban aquatic ecosystems have been subjected to unprecedented threats and challenges. In this study, we visited 48 sites, of which 14 were reservoir sites, in water bodies in Jinan, China, on six occasions in May, August, and October of 2014 and 2015. We sampled fish, macroinvertebrates, and phytoplankton assemblages and physicochemical factors at each site. We used the richness and diversity of fish, macroinvertebrates, and phytoplankton to evaluate the condition of the aquatic ecosystems of the river sites. We also evaluated the water quality of the reservoir sites using the physicochemical factors of the State Environmental Protection Administration of China. We classified the results into five levels—excellent, good, moderate, poor, and bad—with the comprehensive evaluation index (CEI). More than 40% of the sampling sites were in either poor or bad condition. Nearly half of the excellent or good sites were in the south of Jinan. The CEI was significantly different between the reference and impaired sites; it was significantly and positively correlated with the qualitative habitat evaluation index and was significantly and negatively correlated with conductivity, total alkalinity, and ammonia nitrogen.     

西藏牛皮消的化学成分研究

从西藏牛皮消(Cynanchum saccatum)乙醇提取物的乙酸乙酯萃取部位分离出13个化合物,通过理化性质和波谱分析,分别鉴定为对羟基苯乙酮(1)、3,4-二羟基苯乙酮(2)、2,4-二羟基苯乙酮(3)、2,5-二羟基苯乙酮(4)、白首乌二苯酮(5)、3,5-二羟基苯甲酸甲酯(6)、对羟基苯甲酸(7)、2,5-二羟基苯甲酸甲酯(8)、3,3'-二甲氧基-4,9,9'-三羟基-苯并呋喃木脂素-7'-烯-9-O-β-D-吡喃葡萄糖苷(9)、加加明3-O-β-D-加拿大麻吡喃糖基-(1→4)-β-D-夹竹桃吡喃糖基-(1→4)-β-D-夹竹桃吡喃糖苷(10)、青阳参苷元3-O-β-D-加拿大麻吡喃糖基-(1→4)-β-D-加拿大麻吡喃糖基-(1→4)-β-D-夹竹桃吡喃糖基-(1→4)-β-D-加拿大麻吡喃糖苷(11)、β-谷甾醇(12)和β-胡萝卜苷(13).其中化合物9为首次从鹅绒藤属中分离得到,化合物1--3、5--8、10、11、13为首次从该植物中分离得到.     

Ce3+/Tb3+-coactived NaMgBO3 phosphors toward versatile applications in white LED,FED, and optical anti-counterfeiting

Ce³⁺/Tb³⁺ co-doped NaMgBO₃ phosphors were successfully synthesized by solid-state method. Under 381 nm excitation, the cyan emission owing to the 5d → 4f of Ce³⁺ ions and green emissions arising from the ⁵D₄ → ⁷F_J (J = 6, 5, 4, and 3) transitions of Tb³⁺ ions were seen in all the phosphors. Through theoretical analysis, one knows that the energy transfer from Ce³⁺ to Tb³⁺ ions with high efficiency of 83.74% was contributed by dipole–dipole transition. Furthermore, the internal quantum efficiency of NaMgBO₃:0.01Ce³⁺,0.03Tb³⁺ phosphor was 54.28%. Compared with that of at 303 K, the emission intensity of the developed products at 423 K still kept 73%, revealing the splendid thermal stability of the studied phosphors. Through utilizing the resultant phosphors as cyan-green components, the fabricated white-LED device exhibited an excellent correlated color temperature of 2785 K, high color-rendering index of 85.73, suitable luminance efficiency of 25.00 lm/W, and appropriate color coordinate of (0.4279, 0.3617). Aside from the superior photoluminescence, the synthesized phosphors also exhibited excellent cathode-luminescence properties which were sensitive to the current and accelerating voltage. Furthermore, the NaMgBO₃:0.01Ce³⁺,0.03Tb³⁺ phosphors with multi-mode emissions were promising candidates for optical anti-counterfeiting. All the results indicated that the Ce³⁺/Tb³⁺ co-doped NaMgBO₃ phosphors were potential multi-platforms toward white-LED, field emission displays, and optical anti-counterfeiting applications.     

Structure and properties of bio-based polyurethane coatings for controlled-release fertilizer

Two kinds of bio-based polyurethane coatings for controlled-release urea were prepared by in-situ polymerization used castor oil and liquefied starch as raw materials, respectively. Scanning electron microscopy (SEM) showed that the section morphology of castor oil based polyurethane (Castor-PU) coating was uniform and dense, and that of liquefied starch based polyurethane (Starch-PU) coating had certain proportion of microporous. Infrared spectroscopy (IR) showed that the two coatings had typical urethane characteristic structure, but the difference was that the Starch-PU had obvious unreacted isocyanate structure. Differential scanning calorimetry (DSC) showed that the glass transition temperature of the two coatings was around 58°C, but the Castor-PU had a crystallization domain with obvious crystallization melting peak at 130°C. Thermogravimetric analysis (TG) showed that the thermal stability of Castor-PU was significantly higher than that of Starch-PU. The controlled-release property test showed that when the coating ratio was 2.8%, the nutrient release longevity of urea coated with Castor-PU was 49 days and that of urea coated with Starch-PU was 14 days. The reasons for the poor controlled-release performance of Starch-PU were analyzed, which probably caused by concentrated sulfuric acid and hydrophilic dispersant added in the liquefied starch.     

基于FPGA与LabVIEW的DDS任意信号发生器设计

实现了一种基于FPGA与LabVIEW平台的任意波形发生器。通过FPGA搭建硬件平台,与LabVIEW上位机软件实现串口通信,实时调整FPGA内部波形数据,可实现正弦波、方波、锯齿波、三角波、高斯白噪声、叠加正弦波、自定义公式等常规波形,同时也可以手动绘制任意波形,充分发挥了软件的灵活性。通过参数的设定,可方便地设计各种复杂波形。本设计在EP4CE15F17C8芯片上实现,与LabVIEW上位机软件协同工作,经测试系统具有良好的稳定性、灵活性。     

基于指向路径分次删剪的移动Agent通信算法

基于移动agent环境,在应用程序的开发时agent的移动为应用程序找到一种好的通信处理方式。因此通讯算法要面对更多的挑战,最主要的就是agent移动和消息传递之问的异步性而带来的通信不可靠问题。由于目前解决此类问题的算法和机制都有不足之处,本文就针对此类问题来介绍一种新的agent通信算法,即S-COMP算法,它综合了多种手段,主要有:集中同步、指向路径分次删剪、途经节点转发、Home寻址等,能够满足各种不同需求的agent的通信特点,既可以保证适应性和效率,同时也具有可靠性。     

A study on effects of security risks on acceptance of enterprise cloud service: moderating of employment and non-employment using PLS multiple group analysis

This paper analyzed the effects of security risk factors fit for cloud computing paradigm on the acceptance of enterprise cloud service with intent to illuminate the factors for vitalizing the adoption of corporate cloud services in the future. The acceptance intention was set as a dependent variable. Independent variables were set in reference to the technology acceptance theory. Security risks were categorized into compliance risk, information leakage risk, troubleshooting risk and service discontinuation risk to design a model for analysis.