氮化碳修饰的氧化锌纳米线阵列的制备及其光电催化应用

研究了氮化碳修饰的氧化锌纳米线阵列作为光阳极在光电化学(PEC)电池中的应用。首先采用水热法制备氧化锌纳米线阵列,用二氰二胺制备石墨状氮化碳(g-C_3N_4)和无定形氮化碳(a-C_3N_4)。然后用不同浓度的g-C_3N_4和a-C_3N_4悬浊液修饰氧化锌纳米线阵列。通过SEM、XRD、FT-IR、XPS、UV-Vis等方法表征样品的结构与成分,紫外-可见光吸收光谱表明氧化锌纳米线阵列在可见光区的光吸收强度随着氮化碳悬浊液浓度的增加而提高,并且在相同条件下,a-C_3N_4/ZnO比g-C_3N_4/ZnO在可见光区有更好的吸收。将一系列氮化碳修饰的氧化锌纳米线阵列制作成光阳极器件,并进行光电化学测试,氮化碳的修饰可以使氧化锌纳米线阵列的光电催化性能有显著提高,并且a-C_3N_4/ZnO比g-C_3N_4/ZnO在相同条件下能产生更大的光电流。这些结果表明,氮化碳修饰的氧化锌纳米线阵列有潜力应用于PEC电池领域。     

微波水热法氧化锌的低温合成及发光特性研究

采用微波水热合成的方法,在95～150℃的生长温度下得到了氧化锌(ZnO)样品,扫描电镜(SEM)的结果表明,当生长温度从95℃变为150℃时,样品的结构从六方柱状结构颗粒变为小颗粒团聚成的球状结构.由X射线衍射结果可知,低温生长的样品为氧化锌,当生长温度升高后有其他杂质峰出现.由光致发光结果可知,随着生长温度的升高,可见光发光的相对强度增强,这表明样品中的缺陷增多.95℃下生长样品的变功率的荧光光谱表明,随着入射光功率的增大,样品的带边发光峰从3.233 eV变化到3.014 eV,出现了明显的红移;可见光发光与带边发光强度的比值先增大后减小,表明可见光的发光与带边发光有明显的竞争关系.     

纳米氧化锌(ZnO)催化超声波降解酸性红B的研究

采用高温活化处理过的纳米氧化锌(ZnO)粉末为催化剂,研究了超声照射对酸性红B的降解.另外,还考查了超声照射时间,酸性红B初始浓度和纳米ZnO的添加量对酸性红B降解反应的影响.结果表明:在纳米ZnO作用下,酸性红B的超声降解效果明显优于单纯超声波照射降解.降解动力学符合一级反应.在超声波频率40 kHz,输出功率50W,催化剂用量1.0 g/L,pH为7.0,温度25℃,酸性红B水溶液初始浓度10 mg/L的条件下,照射120min左右时降解率即可达到86%以上.     

溶液法制备ZnO多晶薄膜电阻开关耐受性衰退物理机制

利用溶液法制备出平整致密的ZnO多晶薄膜,微结构观测分析表明ZnO晶粒为六方纤锌矿结构,平均粒径约为23.7 nm,由薄膜样品的紫外-可见光吸收谱计算出其光学带隙宽度约为3.3 eV. Ag/ZnO/ITO三明治结构单元的电流-电压曲线呈现出稳定的双极性电阻开关特性:置/复位电压小于±0.4 V,在-0.1 V的读取电压下可获得10~3–10~4的高/低电阻值比,明显优于类似溶液法制备ZnO薄膜的电阻开关性能.然而,在周期性电场力作用下,ZnO多晶薄膜内定向漂移的自由氧离子逐渐被晶格氧空位捕获成为不可移动的晶格氧原子.膜内氧空位缺陷浓度的逐渐降低导致膜内氧空位导电细丝通道越来越细,器件无法长时间维持稳定的低电阻态.因此,随着循环周期数的增加,器件的低电阻态逐渐向高电阻态衰退,直至电阻开关窗口消失.     

聚合物稳定液晶调光器件厚度对其电光性能的影响

通过采用紫外光聚合诱导相分离法制备聚合物稳定液晶调光器件,利用紫外可见分光光度计来研究器件的不同厚度对聚合物稳定液晶调光器件电光性能的影响. 结果表明：随着器件厚度的增加,器件的关态透光率降低,阈值电压升高,饱和电压升高;当器件厚度为5 m时,聚合物稳定液晶智能调光器件的电光性能优良,未通电时,透光率高达97%,当施加40V电压时,透光率低于10%;响应时间非常短,灵敏度非常高,从关态到开态响应时间仅仅需要0.025 s,从开态到关态响应时间需要0.06 s. 这些优异性能使得基于聚合物稳定液晶的智能窗在室内光线智能管理领域有着巨大的应用潜力.     

SDS辅助微波水热法合成氧化锌纳米结构

为了解决ZnO纳米材料在光催化处理染料溶液的效率低问题,以乙酸锌和氢氧化钠为原料,通过微波水热法制备了纳米ZnO光催化剂.利用扫描电镜(SEM),X射线衍射(XRD)和紫外可见吸收光谱(UV-Vis)等检测手段对ZnO产物的形貌和结构进行表征;以十二烷基硫酸钠(SDS)作为表面活性剂,研究了表面活性剂的含量对氧化锌纳米结构的影响;以甲基橙溶液为降解物,研究了ZnO产物的光催化性能.结果表明：当驱体溶液添加1.5 g的SDS时,产物呈现海胆状结构,平均直径约为1.5μm; SDS的加入提高了材料的比表面积及可见光利用率,当可见光照射100 min时,该产物对MO溶液具有很好的降解效果,其降解率则高达96.6%,远高于未添SDS的产物.     

基于ZnO缓冲层的有机太阳能电池数值分析

氧化锌(ZnO)材料具有良好导电性、光透性和稳定性,在光电器件中具有重要用途.利用AMPS-1D探究ZnO作为缓冲层对有机太阳能电池性能的影响.研究发现:添加ZnO缓冲层的有机太阳能电池开路电压、光电转化效率等性能有显著的提高; 电子-空穴产生率和空穴电流密度随着ZnO薄膜厚度增加而减小,而电荷态密度和电子电流密度随着ZnO薄膜厚度增加而增大.     

Er3+:Y3Al5O12/ZnO复合物的制备及其光催化性能的研究

通过溶胶凝胶、水热法合成了上转换发光剂Er~(3+):Y_3Al_5O_(12)掺杂的ZnO复合物可见光催化剂,采用X射线衍射仪(XRD)和扫描电镜(SEM)进行表征.以甲基橙染料为研究对象,研究了Er~(3+):Y_3Al_5O_(12)/ZnO复合物在可见光照射的光催化活性.此外,还研究了焙烧温度、焙烧时间、可见光照射时间和强度、染料溶液初始浓度和催化剂的用量对甲基橙染料降解率的影响.结果表明,加入上转换发光剂Er~(3+):Y_3Al_5O_(12)有效提高了降解率,且催化剂的用量为1.00g/L时降解效果最好.     

邻苯二酚螯合生长氧化锌棒状结构光致发光增强

通过水热合成方法,研究了邻苯二酚作为螯合剂对氧化锌(ZnO)一维棒状材料结构及其光致发光的作用.实验发现,通过调节邻苯二酚的浓度,可以显著改变ZnO一维棒状材料的形貌特征与长径比.结合XRD测试发现随着邻苯二酚的加入,ZnO一维棒状材料的晶化程度显著提高.随着邻苯二酚加入量增大,ZnO晶体沿(100)面方向呈现择优生长的趋势,当邻苯二酚加入量为1 g/L时,ZnO晶体晶化程度最高.另外,光致发光光谱测试发现,ZnO一维棒状材料在紫外以及可见光波段均存在显著的光致发光增强.结合ZnO一维棒状材料的形貌及物相分析,揭示了螯合剂引入后造成的ZnO材料表面缺陷量与晶化程度对光致发光增强的影响.本工作不仅揭示了邻苯二酚在ZnO材料生长中的螯合作用,同时通过邻苯二酚加入量的调控进一步提高了ZnO的光致发光性能.     

染料掺杂的向列相液晶智能调光器件的开关态特性

提出了一种染料掺杂的向列相液晶智能玻璃器件的制作过程,并研究了它的开关态特性.先在上下两基板（ITO）上涂覆聚酰亚胺取向层,将液晶平铺在下基板上,再用带有密封胶框的上基板沿同一摩擦取向方向与下基板压合,制得向列相液晶器件.未加电场时,液晶在取向层的作用下形成平行与基板的多畴排列状态;施加电场后,液晶逐渐在电场作用转向,由平行于基板的多畴排列状态转变为垂直于基板的单畴排列状态,可见光在液晶器件中由散射转为透射,由关态转为开态,从而实现其明暗的切换.染料浓度与驱动电压共同影响器件的透射率.器件开关态阈值电压随器件厚度的增大而增大,在染料液晶浓度5%,盒厚30m时,器件的阈值电压为5 V,饱和电压为15 V,此时智能玻璃的透射率最高,明暗切换特性越好.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with