Stationary Fluid Dynamic Behaviour of V-Shaped Diffuser/Nozzle Elements for Valveless Micropump

A novel type of V-shaped （isosceles triangle cross-section） diffuser/nozzle element is proposed for use for valveless micropump. Stationary fluid dynamic behaviour of V-shaped diffuser/nozzle elements in a valveless micropump is investigated by experiment and simulation. Both the results agree well with each other when the Reynolds number is higher than 100 and the pressure loss coefficient ratio of micropump nearly always keeps a constant. For a single V-shaped diffuser, the general trends of variation of pressure loss coefficient with opening angle and Reynolds number are opposite in small and large angles. Compared with conical and flat-wall diffusers, V-shaped diffuser shows the smallest pressure loss when the Reynolds number is 200.     

Nitrogen Dioxide Sensing Properties and Mechanism of Copper Phthalocyanine Film

Copper phthalocyanine film, a p-type organic semiconductor, is synthesized by vacuum sublimation and its surface morphology is characterized by SEM. A silicon-based copper phthalocyanine film gas sensor for NO2 detection is fabricated by MEMS technology. The results show that the resistance and sensitivity of copper phthalocyanine film decrease obviously as the NO2 concentration increases from Oppm to lOOppm. However, the sensitivity nearly keeps a constant of O. 158 between 30 ppm and 70 ppm. The best working temperature of the gas sensor is 90℃ for NO2 gas concentrations of lOppm, 20ppm and 30ppm, which is much lower than that of general metal oxide gas sensor.     

Two Copper Complexes Based on Pyrazole-3-carboxylic Acid as Heterogeneous Catalysts for Highly Selective Oxidation of Alkylbenzenes

Two new copper complexes based on pyrazole-3-carboxylic acid(H_2pca)ligand,Cu(Hpca)_2(H_2O)_2·2H_2O(1)and Cu_2(pca)_2(H_2O)_4(2)have been synthesized and fully characterized by single-crystal X-ray diffraction(SXRD),infrared spectroscopy(IR),thermal gravity analysis(TGA),powder X-ray diffraction(PXRD)and elemental analyses.Complex 1 is mononuclear while complex 2 shows a dinuclear structure.Complex 1 crystallizes in the monoclinic system,space group P2_1/c with Z=2,a=6.5591(5),b=21.696(2),c=4.9486(2)?,V=680.94(9)?~3,F(000)=366,D_c=1.745 g/cm~3,μ=1.650 mm~(-1),the final R=0.0340 and w R=0.0792.Complex 2crystallizes in the monoclinic system,space group P2_1/n with Z=2,a=5.1935(4),b=9.6052(7),c=12.7347(9)?,V=634.44(8)?~3,F(000)=420,D_c=2.195 g/cm~3,μ=3.404 mm~(-1),the final R=0.0305 and w R=0.0653.The three-dimensional frameworks of two complexes are formed by the O-H···O and N-H···O hydrogen bonding interactions.Notably,two copper complexes are further used as catalysts in the oxidation of alkylbenzenes using t-butylhydroperoxide(TBHP)as the oxidant and they exhibit excellent catalytic performance(Conv.up to 98.9%,Sele.up to 98.7%).     

采用优化的DFTB参数对铜(111)表面碳二聚化的分子动力学研究（英文）

针对铜表面化学反应,我们发展了一套铜-碳体系的密度泛函紧束缚(DFTB)参数。测试结果表明这套参数可以很好的描述吸附铜或碳原子前后铜表面的几何结构和能量。基于这套参数,我们对Cu(111)表面的碳二聚化过程进行了分子模拟研究。即使在高温下,直接的分子动力学模拟也很难观察到碳二聚体的形成。这是因为高温下铜表面显著的结构弛豫一定程度上阻止了二聚化。为了研究高温下铜表面碳二聚化的机理,我们进行了赝动力学模拟。发现在二聚化的过程中,碳原子形成C-Cu-C桥状结构以后,会绕中间Cu原子转动,最后形成碳二聚体。1300 K下碳二聚化的自由能垒约0.9 eV。     

以生活痛点为驱动性问题的项目式实验教学实践——深色和浅色衣物混洗串色

在项目式教学中,驱动性问题的设计和实施是保证项目式学习高效运行的关键。以生活痛点“深色和浅色衣物混洗串色”为真实情境,开展驱动性问题的设计和实施策略研究,开展基于实验教学目标达成度的驱动性问题反思与再设计研究,对轻化工程专业实验教学进行创新改革尝试,以突破传统的验证性实验教学的弊端。     

植物酶催化光度法测定痕量甲胺磷的初步研究

对植物酶催化酯类检测痕量有机磷农药残留量的方法进行了初步研究。在乙酸-乙酸钠的缓冲体系中,应用植物淀粉酶促进α-乙酸萘酯分解生成α-萘酚,甲胺磷农药抑制淀粉酶的活性,淀粉酶的活性随甲胺磷浓度增加而降低,α-乙酸萘酯分解生成的α-萘酚量也减少,以FeCl3指示反应,反应生成一种紫色络合物,利用该反应对甲胺磷进行定量测定。确定了反应的最佳条件,方法已应用于蔬菜表面甲胺磷残留量的分析。     

固相萃取-气相色谱-串联质谱法同时测定人体尿液中4种有机磷农药代谢物

建立了同时测定尿液中4种有机磷类农药代谢物的气相色谱/串联质谱分析方法.尿液样品以WCX固相萃取柱富集提取,乙酸乙酯-乙腈(70∶30,V/V)再萃取,浓缩干燥,甲苯溶解,N-叔丁基二甲基甲硅烷基-N-甲基三氟乙酰胺衍生化.采用HP-5MS色谱柱(30 m×0.25 mm×0.25 μm)程序升温分离,串联质谱多反应检测,内标法定量.通过比较尿样中代谢物在不同萃取溶剂、固相萃取柱及pH值洗脱液等条件下的回收率,优化了前处理方法.在0.2～ 200 μg/L范围内,4种代谢物峰面积与内标峰面积的比值与质量浓度的线性关系良好(R2≥0.992),方法检出限为0.083 ～0.667μg/L,定量限为0.2～2.0 μg/L,平均回收率为54.1％～68.6％,相对标准偏差均小于8.5％(n=6).本方法稳定、可靠,分析时间短,不需要使用大量有机溶剂,可同时处理大批量样品,适用于人群有机磷类农药暴露情况的评估.     

概念的建构过程应促进学生的认识发展——“溶解度”的教学与思考

以"溶解度"的概念教学为例,分析概念建构过程中如何促进学生的认识发展。在概念教学中,应关注学生的前科学认识,挖掘学生的认识角度和思路,发展学生的认识方式,从而形成学生的认识能力。     

大气湍流对空间目标偏振成像探测的影响

为研究大气湍流对空间目标偏振成像探测准确度的影响,构建了大气湍流影响下的偏振成像探测模型,并对大气湍流导致的空间目标偏振度探测偏差进行仿真分析.通过对分时和同时偏振成像方式进行仿真,发现大气湍流会对空间目标偏振成像探测准确度造成明显影响,且对分时偏振成像探测准确度的影响明显大于同时偏振成像方式.通过自适应系统校正部分低阶像差,能明显减小大气湍流对偏振成像探测准确度的影响.为了兼顾图像信噪比和大气湍流影响下的偏振成像探测准确度,给出了一种结合分时和同时成像方式的改进偏振成像探测方式,大气湍流对其的影响略大于同时偏振成像方式,但该方式图像信噪比明显优于同时偏振成像方法.另外仿真分析发现,采用多帧图像叠加能效减小大气湍流带来的空间目标偏振成像探测偏差,在使用分时偏振成像方式时效果尤为明显.     

北仑地区的岸滩动态

本文依据水文、沉积和地貌资料,分析论证了北仑地区的岸滩动态,认为北仑地区岸滩已接近动态平衡,具备开辟深水良港的自然条件。