养殖水域悬浮沉积物对几种酚类环境激素污染物的吸附行为

采用高效液相色谱法研究了宁波市象山港某养殖场悬浮沉积物对壬基酚、辛基酚及双酚A 3种酚类环境激素的吸附行为. 结果表明: 壬基酚、辛基酚及双酚A在悬浮沉积物上的吸附是一个复合动力学过程, 吸附量具有波动特征; 吸附等温线可用Henry线性分配模型及Freundlich模型进行数学描述; 沉积物对3种酚类环境激素的平衡吸附量大小为壬基酚>辛基酚>双酚A; 有机质含量影响壬基酚、辛基酚及双酚A在沉积物中的吸附行为, 3种沉积物的平衡吸附量大小表现为加腐殖酸沉积物>沉积物原样>去除有机质的沉积物; 酚类环境激素在沉积物中的浓度积累增大了养殖水域底栖生物的接触风险.     

悬空石墨烯对其表面金纳米膜形貌的影响

石墨烯与金属间的相互作用是石墨烯器件研究中的关键问题之一,其涉及石墨烯器件的电学接触、锂离子电池石墨烯电极、石墨烯金属光学等方面.本文重点研究了不同层数的悬空石墨烯表面金纳米膜退火前后的形貌演化过程,观测到两个重要的现象:1)排除基底影响后的悬空石墨烯层数可以通过金纳米膜的形貌特征进行确认,但其随层数的变化趋势与有基底支撑的石墨烯正好相反;2)退火处理后的悬空石墨烯上的金纳米膜形貌演化过程具有类似水滴在荷叶上的行为.对悬空石墨烯表面金属纳米膜在退火前后的形貌变化规律及其现象背后的物理机理进行了详细的讨论和理论解释.     

系统压力对含悬浮颗粒油液的影响研究

油液在运行过程中不可避免地会产生颗粒物,影响油液的正常使用,甚至出现设备故障,因而分析含悬浮颗粒油液的动态特征,掌握在不同压力变化条件下油液及颗粒物的变化规律具有重要意义。利用两相流体理论建立了含悬浮颗粒油液的悬浮流动力学模型,通过特征线法进行了数值求解,将数值结果与实验数据比较,具有较好的一致性;根据所建模型,分析了不同系统压力条件下悬浮流中各相的脉动规律。结果表明,流场中各相参数的脉动幅值随着系统压力的增加而增大;管路始端和终端各相参数的脉动时刻分别位于1/4脉动周期(T)的奇数倍和偶数倍处,管路中段各相参数的脉动时刻则位于T/8的奇数倍处;悬浮颗粒速度会受到油液速度拖曳力作用,其变化趋势与油液速度基本一致,颗粒浓度分布与油液压力的变化趋势完全相反。     

菱镁矿悬浮态与堆积态煅烧对产物特性的影响

利用实验室自制小型模拟悬浮态煅烧装置和马弗炉,对菱镁矿进行快速煅烧试验制备轻烧氧化镁,分别对悬浮态和堆积态的煅烧产物进行分解率、XRD、SEM、活性等分析,探讨两种煅烧方式对轻烧氧化镁特性的影响.结果表明:相对于堆积态煅烧,菱镁矿经悬浮态煅烧1 min后分解率即可达到98;以上,得到的轻烧氧化镁晶粒尺寸小、结晶度低,比表面积大、表现出很高的活性;悬浮态煅烧显著强化了热传递过程,加快了反应速度,生产效率成倍提高,产品性能好、质量稳定,可应用于大规模生产高活性轻烧氧化镁.     

Temperature-dependent specific heat of suspended platinum nanofilms at 80-380 K

Metallic nanofilms are important components of nanoscale electronic circuits and nanoscale sensors. The accurate characterization of the thermophysical properties of nanofilms is very important for nanoscience and nanotechnology. Currently, there is very little specific heat data for metallic nanofilms, and the existing measurements indicate distinct differences according to the nanofilm size. The present work reports the specific heats of 40-nm-thick suspended platinum nanofilms at 80-380 K and ~5×10^-4 Pa using the 3ω method. Over 80-380 K, the specific heats of the Pt nanofilms range from 166-304 J/(kg·K), which are 1.65-2.60 times the bulk values, indicating significant size effects. These results are useful for both scientific research in nanoscale thermophysics and evaluating the transient thermal response of nanoscale devices.     

Three-dimensional vertical ZnO transistors with suspended top electrodes fabricated by focused ion beam technology

Three-dimensional(3D)vertical architecture transistors represent an important technological pursuit,which have distinct advantages in device integration density,operation speed,and power consumption.However,the fabrication processes of such 3D devices are complex,especially in the interconnection of electrodes.In this paper,we present a novel method which combines suspended electrodes and focused ion beam(FIB)technology to greatly simplify the electrodes interconnection in 3D devices.Based on this method,we fabricate 3D vertical core-double shell structure transistors with ZnO channel and Al₂O₃ gate-oxide both grown by atomic layer deposition.Suspended top electrodes of vertical architecture could be directly connected to planar electrodes by FIB deposited Pt nanowires,which avoid cumbersome steps in the traditional 3D structure fabrication technology.Both single pillar and arrays devices show well behaved transfer characteristics with an Ion/Ioff current ratio greater than 106 and a low threshold voltage around 0 V.The ON-current of the 2×2 pillars vertical channel transistor was 1.2μA at the gate voltage of 3 V and drain voltage of 2 V,which can be also improved by increasing the number of pillars.Our method for fabricating vertical architecture transistors can be promising for device applications with high integration density and low power consumption.     

氢化物发生原子荧光结合计算法测定大气颗粒物中砷的形态

运用碱式消解法对样品进行前处理,采用氢化物发生-原子荧光光谱数学计算法测定大气颗粒物中As(Ⅲ)和As(Ⅴ)的含量。探讨了还原剂用量、酸介质及其酸度、载气及屏蔽气流量和观测高度等对荧光强度的影响,分析了共存离子对砷测定的干扰。在选定的最佳条件下,得到检出限为0.34μg/L,加标回收率为87.8%～108.2%。方法可用于测定大气颗粒物中不同形态的砷。     

Modeling of mixed liquor inorganic suspended solids and membrane flux at different ratio of SRT to HRT in a submerged membrane bioreactor

In order to investigate the influence of mixed liquor inorganic suspended solids (MLISS) on membrane flux at different ratio of sludge retention time (SRT) to hydraulic retention time (HRT) in a submerged membrane bioreactor (SMBR), a pilot scale test was conducted for 452 days using traditional Chinese medicine (TCM) wastewater as influent. SRT/HRT was controlled at 150, 480 and 750, respectively. The experimental results showed that the average values of MLISS were 1271.9, 1664.5 and 6898.8 mg/L at different SRT/HRT, respectively; MLISS were accumulated from 265.5 g/h to 4912.93 g/h, which indicated that SMBR could not steadily operate for a long period without sludge withdrawal. Sludge oxygen utilized rate (SOUR) decreased from 5.115 to 1.292 mgO₂/(gVSS h) and volume oxygen utilized rate (VOUR) increased from 10.84 to 18.13 mgO₂/(L h). Model of membrane flux and MLISS were developed under different temperature and operational pressure by regressions, which were then satisfactorily employed to predict the trend of membrane flux during the experiment.     

A comparative study on wear and friction characteristics of phenolic composite coatings filled with different morphologies ZnO

In this paper, different morphologies ZnO (disk‐like, rod‐like, and nanoparticles) were introduced into phenolic composite coatings to comparatively investigate the tribological properties. The structural and morphological characterization was conducted with Raman spectroscopy, X‐ray diffraction, and scanning electron microscopy. The tribological performances of composite coatings were evaluated using ring‐on‐block tester under dry condition at room temperature. Experimental results indicated that composite coatings filled with 1 wt% ZnO micro‐disks possessed the optimal tribological performances. It was attributed to the strong interfacial interaction between ZnO micro‐disks and phenolic matrix induced by their specific polar structure. Moreover, different loads and sliding speeds were employed to further evaluate the tribological performances of ZnO micro‐disks/phenolic composite coatings. The outcome revealed that ZnO micro‐disks were potential anti‐wear fillers under harsh condition.     

小型自准直式光电传感器性能测试系统

为标定小型实心转子静电陀螺仪用自准直式光电传感器的性能，设计了一个专用的性能测试系统。传感器性能测试表明，被测小型自准直式光电传感器的分辨率优于1^#，传感器性能测试系统满足使用要求。