Flow Characteristics of Non-Polar Organic Liquids with Small Molecules in a Microchannel

用去离子水及有机液体在内径约为25μm的石英圆管内进行了流量特性实验.液体分子量范围为18～160,动力黏性系数的范围为0.5～1 mPa.s.实验雷诺数范围为Re<8.所用有机液体为:四氯化碳、乙基苯及环己烷都是非极性液体,其分子结构尺度小于1 nm.实验结果表明,在定常层流条件下,圆管内的液体流量与两端压力差成正比,其压力-流量关系仍符合经典的Hagen-Poiseuille流动.这说明非极性小分子有机液体在本实验所用微米尺度管道中其流动规律仍符合连续介质假设.鉴于微尺度流动实验的特殊性,文中还介绍了微流动实验装置,分析了微尺度流动测量误差来源及提高测量精度的措施.

Competitive adsorption between bovine serum albumin and collagen observed by atomic force microscope

Atomic force microscopy (AFM) was used to study the competitive adsorption between bovine serum albumin (BSA) and type I collagen on hydrophilic and hydrophobic silicon wafers. BSA showed a grain shape and the type I collagen displayed fibril-like molecules with relatively homogeneous height and width, characterized with clear twisting (helical formation). These AFM images illustrated that quite a lot of type I collagen appeared in the adsorption layer on hydrophilic surface in a competitive adsorption state, but the adsorption of BSA was more preponderant than that of type I collagen on hydrophobic silicon wafer surface. The experiments showed that the influence of BSA on type I collagen adsorption on hydrophilic surface was less than that on hydrophobic surface.

双倍密度光栅的飞秒压缩技术

飞秒激光技术是当前激光前沿领域的发展内容之一，飞秒脉冲的压缩手段更是其中重要的研究内容。在飞秒脉冲的压缩中，必须使用负的色散元件来补偿飞秒激光钛宝石晶体本身所具有的正的色散以实现压缩。现有的负色散补偿技术包括使用以下三种方式：高密度光栅对、棱镜对、啁啾镜。这三种补偿方式各有优缺点，其中，传统的高密度光栅对只能提供较大的色散量，往往用于飞秒脉冲大范围的展宽和压缩；啁啾镜提供的啁啾量较小，成本也太高；棱镜对的色散能力较小，需要较长的工作距离才能有足够的色散量，往往体积庞大，而且也太重。因此，发展一种新型的补偿

一种基于光纤光栅的毫米波副载波光纤通信方案

提出了一种采用光纤光栅滤波器获得具有一定间隔双波长成分的光脉冲光谱实现毫米波副载波光信号产生的方法。利用逆工程算法，设计了一种变迹叠栅（Moiré）光纤光栅滤波器，给出了相应的模拟结果；并在实验上初步制作了相应的光纤光栅滤波器，验证其可行性。同时基于所设计的光纤光栅和波分复用技术，提出了一种频移键控光纤-无线通信系统Radio Over Fiber系统，为下一代的高速大容量的光纤-无线通信系统系统提供一种可行的备选解决方案。

阶段离子束辅助法制备基频减反膜

在研究阶段离子束辅助制备方式对薄膜性质影响的基础上,采用电子枪蒸发及离子束辅助沉积制备了氧化铪及氧化硅单层膜,采用阶段离子束辅助沉积及全程非离子束辅助沉积制备了基频减反膜。测量了所有样品的弱吸收、残余应力和激光损伤阈值。结果发现,相对电子枪热蒸发制备的样品,离子束辅助沉积的单层膜具有大的弱吸收、低的激光损伤阈值,且张应力减小,压应力增加;阶段离子束辅助沉积制备的减反膜剩余应力变小,弱吸收稍微增加,激光损伤阈值从10.91 J/cm^2增加到18 J/cm^2。分析表明,离子束辅助沉积在引入提高样品激光损伤

石榴裂果发生规律及其防治对策研究

石榴裂果是云南蒙自石榴生产中的突出问题 ;从幼果期至成熟果期均会发生裂果。一般果园裂果率为 2 0 %～2 5 % ,严重的果园达 5 0 %～ 70 % ,造成严重经济损失。在掌握其发生规律的基础上 ,采取春初施足农家肥 ,花期至幼果期每间隔 7～ 10d灌水 1次 ;幼果期至果实膨长期适当控水 ,每间隔 10～ 15d灌水 1次 ;临近雨季前 1个月逐增浇灌水频率 ,每间隔 7～ 10d灌水 1次 ,并以少量多次施肥。缓解前期干旱、气候干燥和与后期雨季连续降雨、果园高湿矛盾 ,增强果皮活性、韧性和抗性 ,控制好主要病虫害。裂果率由原来的 2 0 %～ 2 5 %降为现 2 .5 %～ 3.7%。

生物膜活性测定中TTC-脱氢酶活性测定法的改进

对生物膜活性测定中氯化三苯基四氮唑(TTC)-脱氢酶活性测定法进行了改进,解决了标准曲线制作稳定性差的问题,对测定中的诸多影响因素进行比较分析,确定了改进后的脱氢酶活性测定的最佳条件.结果表明,以甲苯作为萃取剂的液-液分层明显,提取效果好,操作简便.以硫化钠代替连二亚硫酸钠作还原剂,效果较好,显色稳定不褪色.反应的适宜pH值为8.6,适宜温度为38℃.同时确定了生物膜的最佳培养反应时间为6h.

Differentiate performance of eight filter media in vertical flow constructed wetland: Removal of organic matter, nitrogen and phosphorus

A comparative study was conducted to reveal the differentiate effects of eight different filter media including gravel, zeolites, anthracite, shale, vermiculite, ceramic filter media, blast furnace steel slag and round ceramsite. The study mainly related to the eight different filter media's removal performances of organic matter, nitrogen and phosphorus in the vertical flow constructed wetland simulated system, which treating wastewater at hydraulic loading rate of 1000-2500 mm/d. The results indicated that the removal effects were closely related to the physical and chemical properties of medium materials. Anthracite-filled system had the highest removal rate for the total organic carbon (TOC), up to 70%, and the removal rates of other systems ranged from 20% to 30%. As for the five-day biochemical oxygen demand (BOD5), anthracite-filled and steel slag-filled systems had the highest removal rates, also up to 70%, as well as other systems all exceeded 50%. At the same time, for the total nitrogen (TN) and NH4(+)-N, the zeolites-filled and ceramic-filled systems had the best performances with the removal rates of more than 70%, the other way round, the removal rates of other systems were only about 20%. The distinguishable effects were also observed in removal performances of total phosphorus (TP) and total dissoluble phosphorus (TDP). The removal rates of TP and TDP in steel slag-filled systems were more than 90%, a much higher value, followed by that of the anthracite-filled system, more than 60%, but those of other systems being the less. Our study provided a potential mechanism to optimize the filter media design for the vertical flow constructed wetlands.

Preparation and characterization of the stable nc-Si/a-Si : H films

High-quality nc-Si/a-Si:H diphasic films with improved stability were prepared by using the plasma-enhanced chemical vapor deposition technology. In comparison with typical amorphous silicon, the diphasic silicon films possess higher photoconductivity (two orders larger than that of the amorphous silicon film) and fairly good photosensitivity(the ratio of the photo-to dark-conductivity is about 10) and higher stability (the degradation of the photoconductivity is less than 10% after 24h long light soaking with 50 mW/cm(2) intensity at room temperature). In addition, the diphasic silicon film has a better light spectra response in the longer wavelength range. The improvement in photoelectronic properties may be attributed to: the existence of the disorder within the amorphous matrix, which breaks the momentum selection rule in the optical transition and, consequently, results in the large light absorption coefficient and high photosensitivity; the improved medium range order and low gap states density. Excess carriers generated in the amorphous matrix tend to recombine in the embedded crystallites, which suppresses nonradiative recombination within the amorphous matrix and reduces the subsequent defect creation.

基于仿生模式识别的DOA估计方法

该文就仿生模式识别(拓扑模式识别)在非感性抽象对象的信息处理方面的应用作了一些探索,提出了一种基于仿生模式识别的DOA估计方法.这种方法的建模过程是用在实际环境下采集的训练样本构造人工神经网络模型,对环境的适应能力较强,且这种方法的计算量较小,可以实现系统实时处理.实验结果表明:在信噪比为20 dB和0 dB时,该方法的正确估计率可达100%;在信噪比降为-20 dB时,该方法仍有83%的可识别率.

稳定、优质nc-Si/a-Si:H薄膜的研制和特性分析

利用等离子体增强化学气相沉积技术研制出了优质稳定的氢化非晶-纳米晶两相结构硅薄膜.薄膜的光电导率相对于器件质量的非晶硅有两个数量级的提高;光敏性也较好,光、暗电导比可以达到104,此外薄膜的光电导谱具有更宽的长波光谱响应.更为重要的是薄膜的光致退化效应远小于典型的非晶硅薄膜,在光强为50mW/cm2的卤钨灯光照24h后,光电导的衰退小于10%.这种薄膜优良的光电性能源于薄膜中的非晶母体的存在使其在光学跃迁中的动量选择定则发生松弛,因而具有大的光学吸收系数和较高的光敏性;相对于典型非晶硅而言,薄膜的中程有序度得到了较大的改善,并具有小的深隙态密度;薄膜中存在的纳米尺寸的微晶颗粒,提供了光生载流子的复合通道,在非晶母体中的电子空穴对可以转移到微晶颗粒中进行复合,这样抑制了非晶母体中的非辐射复合,从而降低了光致亚稳缺陷产生的概率.

西安地区不同厚度土层土壤co2释放量的差异研究

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