退火温度对ZnS/PS薄膜的晶体结构和光电性质的影响

用脉冲激光沉积法(PLD)在多孔硅(PS)衬底上生长ZnS薄膜,分别在300℃,400℃和500℃下真空退火.用X射线衍射(XRD)和扫描电子显微镜(SEM)研究了退火对ZnS薄膜的晶体结构和表面形貌的影响,并测量了ZnS/PS复合体系的光致发光(PL)谱和异质结的I-V特性曲线.研究表明,ZnS薄膜仅在28.5°附近存在着(111)方向的高度取向生长,由此判断薄膜是单晶立方结构的-βZnS.随着退火温度的升高,-βZnS的(111)衍射峰强度逐渐增大,且ZnS薄膜表面变得更加均匀致密,说明高温退火可以有效地促进晶粒的结合并改善结晶质量.ZnS/PS复合体系的PL谱中,随着退火温度升高,ZnS薄膜的自激活发光强度增大,而PS的发光强度减小,说明退火处理更有利于ZnS薄膜的发光.根据三基色叠加的原理,ZnS的蓝,绿光与PS的红光相叠加,ZnS/PS体系可以发射出较强的白光.但过高的退火温度会影响整个ZnS/PS体系的白光发射.ZnS/PS异质结的I-V特性曲线呈现出整流特性,且随着退火温度的升高其正向电流增

多孔硅的孔隙对硫化锌/多孑L硅光电性质的影响

为了研究衬底多孔硅(PS)的孔隙对硫化锌/多孔硅(ZnS/PS)复合体系的光学性能和电学性质的影响,采用脉冲激光沉积方法在不同孔隙度的PS衬底上沉积了硫化锌薄膜.利用X射线衍射仪、扫描电子显微镜、荧光分光光度计和I-V特性曲线分别研究了PS衬底上ZnS薄膜的晶体结构、表面形貌和ZnS/PS复合体系的光学和电学性质.结果表明,沉积的ZnS薄膜呈立方相晶体结构,沿β-ZnS(111)晶向择优取向生长.随着衬底PS孔隙的增多, ZnS薄膜衍射峰的强度减小,且薄膜表面出现一些空洞和裂缝;在ZnS/PS复合体系的光致发光谱中,PS的发光相对于未沉积ZnS薄膜的PS有所蓝移,随着PS孔隙的增多,该蓝移量增大,而且在光谱中间550nm左右出现了一个新的绿光发射,归因于ZnS的缺陷中心发光.ZnS的蓝、绿光与PS的红光相叠加,整个ZnS/PS复合体系呈现出较强的白光发射.ZnS/PS异质结的 I-V特性曲线呈现出与普通二极管相似的整流特性,在正向偏置下,电流密度较大,电压降较低;在反向偏置下,电流密度接近于0.随着衬底PS孔隙的增多,正向电流增大.该项研究结果为固态白光发射器件的实现奠定了基

半干旱典型草原养分添加对优势物种叶片氮磷及非结构性碳水化合物含量的影响

在7年的养分添加(对照、低磷、低氮、低氮高磷和高氮低磷)试验基础上,测定了内蒙古半干旱典型草原优势种大针茅(Stipa grandis)和羊草(Leymus chinensis)叶片氮、磷、可溶性碳水化合物和淀粉含量。结果表明:两物种叶片氮、可溶性碳水化合物、淀粉及非结构性碳水化合物含量对养分添加有显著的响应(P<0.05),养分添加与物种有显著的交互作用(P<0.05);加氮显著增加了两物种植物叶片氮含量(P<0.05),单加N处理显著降低了两物种叶片中的淀粉含量(P<0.05),单加磷处理显著增加了羊草叶片可溶性碳水化合物含量(P<0.05),高氮低磷处理显著降低两物种叶片非结构性碳水化合物总量(

Synthesis of Ternary Polymer for ABS Coating Resin

用自由基溶液聚合法合成了苯乙烯-甲基丙烯酸丁酯-甲基丙烯酸甲酯三元共聚产物,作为AbS塑料专用涂料树脂.通过分子设计,选择单体种类,改变引发剂用量、反应时间、苯乙烯加料方式等条件,得出一系列共聚产物.用红外光谱仪、核磁共振波谱仪对分子结构进行表征,用凝胶渗透色谱仪进行相对分子质量的测定.通过核磁谱峰积分计算各单体的转化率,跟踪其在反应过程中的变化,分析共聚产物的链段组成均一性.最终合成耐热性较高,数均相对分子质量在2.5万~4万,单体总转化率在95%以上,且链段组成分布均匀的共聚产物.将其用于AbS转印涂料,附着性好,耐热性优良,满足工业需求.In this paper,styrene-butyl methacrylate-methyl methacrylate ternary polymer,which is used as ABS plastic coating resin,was synthesized with the radical solution polymerization.Through molecular design,a series of copolymers were obtained by choosing monomer species,changing initiator amount,reaction time and styrene feeding method.Molecular structure was characterized by infrared(IR)spectrometer and nuclear magnetic resonance(NMR)spectrometer.Molecular weight was determined using gel permeation chromatograph(GPC).The conversion of the monomer was calculated according to the NMR peak integral.Changes of the conversion were tracked during the reaction,and the segment composition uniformity of the copolymer product had been analyzed.Finally,agood heat-resisting ternary polymer product had been synthesized,of which the number-average molecular weight ranged from2.5×104 to 4.0×104.The overall conversion ratio of monomers reached over 95%,and the segment composition of the product was uniformly distributed.When applied as an ABS transfer coating,the product showed good adhesion,excellent heat resistance,and satisfied the industrial demand

Study on the Synthesis of Epoxy Polybutadiene Acrylate and UV Curing Shrinkage

针对紫外光固化胶黏剂固化收缩率较大的问题,合成了一种具有双重固化机理的预聚物——环氧聚丁二烯丙烯酸酯.通过控制变量,得到制备该预聚物的较为理想的合成条件.利用fT-Ir,1H-nMr对预聚物进行了表征,并测定了使用该预聚物的紫外光固化体系的固化收缩率.研究结果表明:在预聚物合成中,反应时间7H,丙烯酸质量分数在5%~20%时为宜;预聚物的环氧值为3.430%时固化效果较好;三苯基膦是较为理想的催化剂;预聚物、乙氧基乙氧基乙基丙烯酸酯(EOEOEA)和正丁基缩水甘油醚(bgE)质量比为60∶10∶25时,固化收缩率可达2.59%.In view of the large curing shrinkage of UV-curing system,a type of prepolymer that has dual curing mechanism,epoxy polybutadiene acrylate,was synthesized.An ideal synthesis condition was achieved by controlling variables.The prepolymer was characterized by FT-IR and 1H-NMR,and the curing shrinkage of this UV-curing system was also studied.The results showed that in the synthesis of prepolymer reaction time was about 7hand the dosage of acrylic acid was 5%-20%(by mass).When the exopy value of the prepolymer was 3.430%,the curing result was better.Triphenylphosphine was an ideal catalyst.In the UV curing when the mass ratio of prepolymer,2-(2-ethoxyethoxy)ethyl acrylate(EOEOEA),and butyl glycidyl ether(BGE),was 60∶10∶25,the curing shrinkage came to 2.59%

地理距离、海拔和气候差异对独龙江流域维管植物群落物种空间相异性的影响

物种相异性(species dissimilarity)主要反映了群落物种组成的时空变化,其与随机和确定性因素之间的关系能揭示群落构建及生物多样性形成和维持的机理。本文以独龙江流域植物群落为研究对象,以群落间Jaccard物种相异性指数为指标,分析它同地理距离、气候和海拔差异之间的关系及各类因子影响的权重。结果表明,群落间Jaccard物种相异性指数变化范围为0.42–1,且随自然对数转换的地理距离、海拔和气候差异(多年日平均温度,年平均降水量)的增大而呈显著的线性增加趋势;地理距离、气候差异和海拔差异可以解释独龙江流域群落物种相异性指数将近30%的变异。地理距离单独解释度为18.80%,气候差异和海拔差异分别可以解释3.47%和0.10%。研究结果表明,独龙江流域群落物种在空间上的更替是环境限制和扩散限制综合作用的结果。群落间物种相异性较大,且影响物种更替的因素中地理距离占有较大的权重,说明在对该地区进行生物多样性保护时,在综合考虑环境因素影响的基础上,还应充分考虑地形的阻隔作用和繁殖体扩散能力的大小

Research on the Treatment of Highly Concentrated Phenolic Wastewater

采用fEnTOn系列方法处理高浓度酚醛废水,考察了各方法对化学需氧量(COd)去除率的影响.首先,确定了fEnTOn-uV氧化中H2O2溶液添加量、fE2+与H2O2摩尔比、PH值、光照时间等因素的较优水平;同时结果表明,将fEnTOn氧化法与超声和紫外光照射联用显著改善了处理效果,COd去除率可以达到90%以上;将絮凝法与fEnTOn-uV联用,聚丙烯酰胺加速絮状物沉淀,COd去除率达到70%左右;用红外和核磁手段表征酚醛废水经fEnTOn-uV氧化后的产物,证明fEnTOn-uV氧化法通过苯环侧链氧化断裂的主要途径进行.Several Fenton-related experiments were used to treat highly concentrated phenolic wastewater.Firstly,the optimal level of each factor in the Fenton-ultraviolet light experiment,such as the amount of H2O2,the mole ratio of Fe2+to H2O2,pH value and UV exposure time,was determined.The treatment effect obviously got improved when Fenton treatment was combined with ultrasonication and ultraviolet light irradiation,in which the removal efficiency of chemical oxygen demand(COD)could reach more than90%.In treating the phenolic wastewater by both flocculation and Fenton-UV,polyacrylamide could accelerate the sedimentary rate of the floccules and the COD removal efficiency was around 70%.Characterization of the flocculate emerging in the Fenton-UV oxidation using FT-IR and 1H-NMR methods proved that oxidation and degradation of the benzene ring′s side chains were the main way of Fenton-UV treatment