Auto-deposition of 210Bi and 210Po on nickel discs and their application in the analysis of natural waters

Journal of Radioanalytical and Nuclear Chemistry - This study presents a time-efficient method of analysing 210Pb, 210Bi, and 210Po in natural waters. The optimum pH (1.00), temperature...     

基于级联PPMgLN晶体的双倍/三倍频双波长激光器

本文演示了紧凑的绿色和近红外双色连续波激光光源,其发射波长分别为516 nm和775 nm。设计并制造了级联的周期性极化掺镁铌酸锂晶体,用于同时转换通信波长的二次谐波(SHG)和三次谐波(THG),可以在相同温度下获得绿色和近红外激光的输出。通过建立一个单程激光测量系统,在2 W泵浦功率下获得516 nm的0.15 mW绿光和775 nm的1.19 mW的光,晶体温度控制在30.8 ℃。实验结果将为单激光器泵浦的紧凑型双波长共线激光器提供重要的案例。     

Comparison of different methodologies for the computation of damped nonlinear normal modes and resonance prediction of systems with non-conservative nonlinearities

Nonlinear Dynamics - The nonlinear modes of a non-conservative nonlinear system are sometimes referred to as damped nonlinear normal modes (dNNMs). Because of the non-conservative...     

Hitherto-Unexplored Photodynamic Therapy of Ag2S and Enhanced Regulation Based on Polydopamine In Vitro and Vivo

Given their superior penetration depths, photosensitizers with longer absorption wavelengths present broader application prospects in photodynamic therapy (PDT). Herein, Ag₂S quantum dots were discovered, for the first time, to be capable of killing tumor cells through the photodynamic route by near-infrared light irradiation, which means relatively less excitation of the probe compared with traditional photosensitizers absorbing short wavelengths. On modification with polydopamine (PDA), PDA-Ag₂S was obtained, which showed outstanding capacity for inducing reactive oxygen species (increased by 1.69 times). With the addition of PDA, Ag₂S had more opportunities to react with surrounding O₂, which was demonstrated by typical triplet electron spin resonance (ESR) analysis. Furthermore, the PDT effects of Ag₂S and PDA-Ag₂S achieved at longer wavelengths were almost identical to the effects produced at 660 nm, which was proved by studies in vitro. PDA-Ag₂S showed distinctly better therapeutic effects than Ag₂S in experiments in vivo, which further validated the enhanced regulatory effect of PDA. Altogether, a new photosensitizer with longer absorption wavelength was developed by using the hitherto-unexplored photodynamic function of Ag₂S quantum dots, which extended and enhanced the regulatory effect originating from PDA.     

氨基功能化磁性CoFe2O4/氧化石墨烯去除电镀废水中Cr(Ⅵ)的研究

使用改良的hummers法制备出的氧化石墨烯为载体,采用共沉淀法制备出磁性CoFe2O4/氧化石墨烯(MGO),再使用三乙烯四胺(TETA)对磁性CoFe2O4/氧化石墨烯进行氨基功能化,制备出氨基功能化磁性CoFe2O4/氧化石墨烯吸附剂.采用X-射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)和扫描电子显微镜(SEM)对TETA-MGO的物相、化学组成和微观形貌进行表征,以TETA-MGO作为吸附剂去除电镀废水中Cr(Ⅵ),探讨吸附性能和吸附机理,分析TETA-MGO在外加磁场下的液固分离和再生吸附性能.结果表明纳米级立方尖晶石相磁性CoFe2O4均匀生长于氧化石墨烯的表面和片层之间,TETA通过C-N键与磁性氧化石墨烯(MGO)相连,氨基功能化成功,活性吸附位点增点.室温下,pH =2时吸附效果最佳,吸附120 min时达到吸附平衡,平衡吸附量约为48.66 mg·g-1,TETA-MGO对Cr(Ⅵ)的吸附动力学和吸附热力学可分别使用拟二级动力学模型和Langmuir等温吸附模型描述,吸附过程主要属于化学吸附控制的单分子层吸附,使用外加磁场可以对TETA-MGO实现简单的固液分离,TETA-MGO经过6次再生吸附后,对Cr(Ⅵ)的吸附量仅下降19.67;,说明具有良好的循环再生吸附能力.     

Bi-2223/Ag异质结的光生电压效应研究

在50 ～ 340 K不同温度下,利用紫色激光(λ=405 nm)对银/铋锶钙铜氧2223异质结界面进行辐照,观测到明显的光生电压效应,发现光生电压的极性分别在超导转变温度TC与320 K附近发生了反转,排除了激光产生的热电势是产生光生电压的原因,分析表明银/铋锶钙铜氧2223异质结界面处存在内建电场:光生电压由异质结界面处的内建电场分离光生电子-空穴对产生的.超导转变温度TC之下以及320 K以上,内建电场方向从超导体指向金属电极;超导转变温度TC与反向温度320 K之间,内建电场从金属指向超导体.     

Fabrication of Microporous Metal–Organic Frameworks in Uninterrupted Mesoporous Tunnels: Hierarchical Structure for Efficient Trypsin Immobilization and Stabilization

Hierarchically porous metal–organic frameworks (HP-MOFs) are promising in various applications. Most reported HP-MOFs are prepared based on the generation of mesopores in microporous frameworks, and the formed mesopores are connected by microporous channels, limiting the accessibility of mesopores for bulky molecules. A hierarchical structure is formed by constructing microporous MOFs in uninterrupted mesoporous tunnels. Using the confined space in as-prepared mesoporous silica, highly dispersed metal precursors for MOFs are coated on the internal surface of mesoporous tunnels. Ligand vapor-induced crystallization is employed to enable quantitative formation of MOFs in situ, in which sublimated ligands diffuse into mesoporous tunnels and react with metal precursors. The obtained hierarchically porous composites exhibit record-high adsorption capacity for the bulky molecule trypsin. The thermal and storage stability of trypsin is improved upon immobilization on the composites.     

Characteristics of black carbon aerosol in Jiaxing,China during autumn 2013

We conducted measurements of black carbon（BC） aerosol in Jiaxing,China during autumn from September 26 to November 30,2013.We investigated temporal and diurnal variations of BC,and its correlations with meteorological parameters and other major pollutants.Results showed that hourly mass concentrations of BC ranged from 0.2 to 22.0 μg/m³,with an average of 5.1 μg/m³.The diurnai variation of BC exhibited a bimodal distribution,with peaks at 07:00 and 18:00.The morning peak was larger than the evening peak.The mass percentages of BC in PM_2.5 and PM₁₀ were 7.1%and 4.8%,respectively.The absorption coefficient of BC was calculated to be 44.4 Mm^-1,which accounted for 11.1%of the total aerosol extinction.BC was mainly emitted from local sources in southwestern Jiaxing where BC concentrations were generally greater than 11 μg/m³ during the measurement period.Correlation analysis indicated that the main sources of BC were motor vehicle exhaust,and domestic and industrial combustion.     

Mass and isotopic concentrations of water-insoluble refractory carbon in total suspended particulates at Mt.Waliguan Observatory(China)

Mass concentration and isotopic values δ¹³C and ¹⁴C are presented for the water-insoluble refractory carbon（WIRC） component of total suspended particulates（TSP）,collected weekly during 2003,as well as from October 2005 to May 2006 at the WMO-GAW Mt.Waliguan（WLG） site.The overall average WIRC mass concentration was（1183±120）ng/m³（n = 79）,while seasonal averages were 2081 ±1707（spring）,454±205（summer）,650±411（autumn）,and 1019±703（winter） ng/m3.Seasonal variations in WIRC mass concentrations were consistent with black carbon measurements from an aethalometer,although WIRC concentrations were typically higher,especially in winter and spring.The δ¹³C PDB value（-25.3 ± 0.8）%.determined for WIRC suggests that its sources are C₃ biomass or fossil fuel combustion.No seasonal change in δ¹³C PDB was evident.The average percent Modern Carbon（pMC） for ¹⁴C in WIRC for winter and spring was（67.2 ± 7.7）%（n = 29）.Lower pMC values were associated with air masses transported from the area east of WLG,while higher pMC values were associated with air masses from the Tibetan Plateau,southwest of WLG.Elevated pMC values with abnormally high mass concentrations of TSP and WIRC were measured during a dust storm event.