Formation of abnormal dual‐peak profiles in large tilt angle boron implantation

Large tilt angle (LTA) implantation has been employed in Si manufacturing processes in many applications, such as lightly doped drain and halo implant. The depth profile of boron ions usually consists of only single peak at incident angle of 0° with respect to the perpendicular of the silicon surface. However, an abnormal dual‐peak profile was observed at LTA (>40°) with incident energy of 160 keV. By using a Monte Carlo method to simulate the ion implant process, it was found that the projected range of boron ions agrees completely with the formation of the first peak position that is shallower in depth, while the cause for the second peak that corresponds with a depth much deeper in the Si substrate was unknown. During the simulation, it was also found that when the tilt angle was increased, the sputtering yields and Si displacements increased significantly, and this phenomenon indicates that during LTA implantation, Si damage may not be negligible anymore. The Si damage effect that was as due to either low Si density or transient Si displacement in the simulation could have led to partial incident boron ions penetrating much deeper into the Si substrate and thus, caused the emergence of the second peak. Copyright © 2016 John Wiley & Sons, Ltd.     

A new type of microemulsion containing task-special ionic liquid [NH2ebim][BF4]

The formation of microemulsions in the presence of cyclohexane, Triton X-100, n-butanol, water, and task-special ionic liquid (TSIL) (1-2-aminoethyl-3-butylimidazolium tetrafluoroborate) was studied at 25°C. The phase behavior of this ternary system was investigated. Three subregions (namely, water-in-oil phase, bicontinuous phase, and oil-in-water phase) were identified in the single-phase region by dynamic light scattering (DLS) technique and electrical conductivity measurement. Microstructures of microemulsions with different water contents have been predicted by using dissipative particle dynamics (DPD) simulation. It was found that the DPD simulations successfully reproduce the experimental results in the article. The location of TSIL in the microemulsions was predicted by DPD simulation further. The result indicates that TSIL is more easy to locate in the surfactant and cosurfactant layer and has amphiphilicity, which provides us new insights into the potential applications of TSIL-based microemulsions in separation and new nano-scale material preparation because of the interaction of TSIL with some special components at the interface of oil and water.     

锑掺杂对钒钛系催化剂低温脱硝活性的影响

用浸渍法制备Sb-V₂O₅-TiO₂催化剂,在质量分数3%V₂O₅-TiO₂催化剂基础上,研究锑的负载量、焙烧温度对催化剂活性的影响。结果表明,锑的负载量为11%（质量分数）,500 ℃焙烧的催化剂具有最佳的SCR活性,在进口浓度为0.07% NO_x、O₂体积分数5%、空速27 000 h^-1的条件下,170 ℃时脱硝活性可达92%。对催化剂进行H₂-TPR表征,发现锑修饰后的催化剂氧化能力增强,使催化剂效率上升。通过XPS和NH₃-TPD表征测试,催化剂表面的锑主要以五价的形式存在且随着锑负载量的增加催化剂表面酸性增强。考察SO₂和H₂O对催化剂的影响发现,加锑催化剂具有一定的抗硫抗水性能。通过FT-IR、TG、孔隙结构测试表明,锑的加入可以有效地抑制硫酸铵盐在催化剂表面的聚集,从而延长催化剂的寿命。     

高性能量子点编码磁性微球的制备

基于改进的层层组装法,以氯仿/正丁醇混合溶液作为反应溶剂,将油溶性CdSSe/ZnS量子点装载到表面氨基修饰的磁性聚苯乙烯微球(MS)表面,通过调节量子点浓度,制备出高性能CdSSe/ZnS量子点编码磁性微球(CdSSe/ZnS-MBs).研究了氯仿和氯仿/正丁醇混合溶液对CdSSe/ZnS-MBs制备效果的影响.结果表明,氯仿/正丁醇混合溶液不仅能避免氯仿等量子点良溶剂对聚合物微球的形貌破坏,同时能促进CdSSe/ZnS量子点高效地装载到磁性微球表面.所制备的CdSSe/ZnS-MBs在水相具有较好的分散性,荧光强度变异系数(CV)小,形貌均一.该方法为简单、精确可控地制备高编码容量的量子点编码微球提供了新思路.     

量子点荧光印迹传感器的计算机模拟设计、制备及检测河水中4-硝基苯酚的应用

将量子点的荧光特性、表面分子印迹技术与计算机模拟技术相结合,分别以碲化镉、4-硝基苯酚、3-氨丙基三乙氧基硅烷和正硅酸四乙酯作为量子点、模板分子、功能单体和交联剂,制得具有荧光特性的分子印迹聚合物.对其结构、形貌、荧光性能和选择性进行了表征,结果表明,该聚合物对4-硝基苯酚具有良好的选择性和灵敏度,线性范围为1.0~80 nmol/m L,检出限为0.05 nmol/m L.将制备的量子点荧光印迹聚合物作为传感器,应用于河水中4-硝基苯酚的测定,加标回收率为98.6%~101.2%,相对标准偏差最高为1.37%.     

基于杂交链式反应辅助多重信号放大的端粒酶灵敏检测

端粒酶是真核细胞维持端粒长度的关键逆转录酶,其生物活性的高低可以为多种癌症的临床诊断和预后治疗提供有价值的信息.本研究以人宫颈癌细胞(HeLa细胞)裂解液中的端粒酶为研究对象,通过借助杂交链式反应辅助多重信号放大策略,提出了一种新颖、灵敏的检测端粒酶电化学方法.首先将端粒酶的延伸引物自组装在金电极表面,当端粒酶存在时,端粒酶能够催化引物的延伸,产生与发卡环探针H1部分互补的序列,进而引发杂交链式反应,形成由两个发卡环探针(H1和H2)交替杂交而形成的DNA长链.由于H1和H2末端均修饰有生物素,加入链霉亲和素修饰辣根过氧化物酶后,辣根过氧化物酶被被连接到电极表面,催化邻苯二胺氧化生成2,3-二氨基吩嗪,产生显著的电化学信号.实验结果表明,本研究建立的端粒酶电化学检测方法高效、可行,线性范围宽,灵敏度高,可以检测每毫升10个HeLa细胞裂解液中的端粒酶.本方法具有较好的选择性,能有效区分端粒酶和对照蛋白.     

基于铕取代多金属氧簇的手性发光液晶材料

The incorporation of europium-substituted polyoxometalate (PM) into chiral amphiphiles is attractive for the fabrication of multifunctional chiral luminescent liquid crystalline materials. Chiral amphiphiles acted as good promoters to trigger the achiral PM to show induced supramolecular chirality through electrostatic interactions, as illustrated by circular dichroism (CD) spectra. Differential scanning calorimetry (DSC), polarized optical microscopy (POM), and temperature-dependent X-ray diffraction (XRD) analysis confirmed that the organic/inorganic hybrid polyoxometalate complex exhibited thermotropic mesomorphic behaviors. In a cast film, the complex displayed intrinsic luminescence that could be adjusted by accurately controlling the temperature. The electrostatic encapsulation of PM with chiral mesomorphic promoters provides an effective method for constructing PM-based chiral luminescent liquid crystalline materials.     

Pd/γ-Al_2O_3催化剂催化氧化邻-二甲苯

利用纳米γ-Al_2O_3(10 nm)和普通γ-Al_2O_3(200-300 nm),采用浸渍法制备了1%(w)Pd/γ-Al_2O_3催化剂,考察了其催化氧化邻-二甲苯的性能以及催化剂的活性在氢气还原前后的区别。实验结果发现1%(w)Pd/γ-Al_2O_3(nano)在H_2还原后催化氧化邻-二甲苯的活性最高,T_(90)为150℃。利用X射线衍射(XRD)、比表面积(BET)、透射电镜(TEM)、X射线光电子能谱(XPS)等表征手段,研究了1%(w)Pd/γ-Al_2O_3催化剂物性结构与催化性能之间的构效关系。结果表明,还原态Pd是H_2还原后催化剂催化氧化邻-二甲苯的活性物种;Pd的颗粒大小与催化剂活性有显著的关系,小粒径有利于催化剂活性提高;纳米γ-Al_2O_3载体与Pd之间的相互作用强,有利于Pd的粒径控制和分散,从而提高1%(w)Pd/γ-Al_2O_3(nano)催化剂的活性。     

Influence of terminal substituent on non-linear S-shaped oligomers consisting of azobenzene moieties at the peripheral arm: Synthesis,characterisation and phase transition behaviour

A series of symmetrical S-shaped mesogens based on 4,4′-bis-(6-bromohexyloxy)biphenyl as a central unit containing two 2-{6-[4-(4-substitutedphenylazo)phenoxy]hexyloxy}phenol as side-chain groups has been successfully synthesised. The terminal substituent was varied from halogen (X = F, Cl, Br and I) to non-halogen (X = C₂H₅ and OC₂H₅). The oligomers with C₂H₅ and OC₂H₅ substituents exhibit predominantly the monotropic nematic (N) phase. The OC₂H₅-containing derivatives possess long-range stability of N phase than its C₂H₅-containing analogue in which it has small range of N phase stability. As for halogen-containing analogues, oligomer with F exhibits monotropic N phase whilst oligomers with Cl and Br exhibit monotropic N and smectic A (SmA) phases. In addition, homologue with Br shows additional phase which is smectic B (SmB) phase upon further cooling. However, the oligomers in which F, Cl and Br were substituted by I exhibits purely monotropic SmA and SmB phases. X-ray diffraction measurements reveal that the smectic phase is inclined to the monolayer structure.     

Cloning,Expression, and Biochemical Characterization of a Novel Acidic GH16 β-Agarase,AgaJ11, from <Emphasis Type="Italic">Gayadomonas joobiniege</Emphasis> G7

A novel β-agarase AgaJ11 belonging to the glycoside hydrolase (GH) 16 family was identified from an agar-degrading bacterium Gayadomonas joobiniege G7. AgaJ11 was composed of 317 amino acids (35 kDa), including a 26-amino acid signal peptide, and had the highest similarity (44 % identity) to a putative β-agarase from an agarolytic marine bacterium Agarivorans albus MKT 106. The agarase activity of purified AgaJ11 was confirmed by zymogram analysis. The optimum pH and temperature for AgaJ11 activity were determined to be 4.5 and 40 °C, respectively. Notably, AgaJ11 is an acidic β-agarase that was active only at a narrow pH range from 4 to 5, and less than 30 % of its enzymatic activity was retained at other pH conditions. The K _m and V _max of AgaJ11 for agarose were 21.42 mg/ml and 25 U/mg, respectively. AgaJ11 did not require metal ions for its activity, but severe inhibition by several metal ions was observed. Thin layer chromatography and agarose-liquefying analyses revealed that AgaJ11 is an endo-type β-agarase that hydrolyzes agarose into neoagarohexaose, neoagarotetraose, and neoagarobiose. Therefore, this study shows that AgaJ11 from G. joobiniege G7 is a novel GH16 β-agarase with an acidic enzymatic feature that may be useful for industrial applications.