Cu_(6)Sn_(5)纳米颗粒对SAC3005/Cu焊点形貌和性能的影响

研究了添加Cu_(6)Sn_(5)纳米颗粒对SAC3005焊料焊点金属间化合物的形貌和性能的影响。采用湿化学法制备Cu_(6)Sn_(5)纳米颗粒,将Cu_(6)Sn_(5)纳米颗粒添加到SAC3005焊料中,经回流焊后,制备SAC3005-xCu_(6)Sn_(5)(x=0%,0.12%,0.18%,质量分数)复合焊点。采用金相显微镜对焊点的横断面进行观察,对焊点的横断面金属间化合物(IMCs)进行测量。采用ANSYS有限元软件对界面IMCs模型进行模拟,分析印刷电路板(PCB板)焊点失效机理。结果表明:添加Cu_(6)Sn_(5)纳米颗粒改性SAC3005/Cu焊点后的IMCs层厚度变薄。Cu_(6)Sn_(5)纳米颗粒的加入抑制了回流焊接过程中IMCs的生长,提高了焊点的可靠性。Cu_(6)Sn_(5)纳米颗粒的添加阻碍了Sn原子和Cu原子在界面处的扩散,抑制了Cu_(6)Sn_(5)IMCs的生长。添加质量分数为0.12%的Cu_(6)Sn_(5)纳米颗粒时抑制效果最好。焊点界面Cu_(6)Sn_(5)层和Cu_(3)Sn层是应力应变集中的地方,焊点交界处为焊点服役过程中的薄弱环节。

Synthesis and Electrical Properties of TiO_2 Nanoparticles Embedded in Polyamide-6 Nanofibers Via Electrospinning

We report on the synthesis and characterizations of TiO2 nanoparticles embedded in polyamide-6composite nanofibers by using electrospinning technique. The influence of substrate on the electrical characteristics of polyamide-6/TiO2 composite nanofibers was investigated. The resultant nanofibers exhibit good incorporation of TiO2 nanoparticles. The doping of TiO2 nanoparticles into the polyamide-6 nanofibers were confirmed by high resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. Photoluminescence（PL） and cathodoluminescence（CL） spectroscopy were also used to characterize the samples.The PL and CL spectra reveal that the as-spun polyamide-6/TiO2 composite nanofibers consisted of overlapping of two broad emission bands due to the contribution of polyamide-6（centered at about 475 nm）, which might originate from organic functional groups of polyamide-6 and TiO2 nanoparticles（centered around 550 nm）. The electrical conductivity of the polyamide-6/TiO2 composite nanofibers on different substrates was carried out.It was found that the electrical conductivity of the polyamide-6/TiO2 composite nanofibers on silicon substrate was in the range of 13 μA, and about 1 to 20 p A for the paper and glass substrates.

6-姜烯酚玉米醇溶蛋白纳米颗粒的构建及其生物利用度分析

为解决6-姜烯酚(6-shogaol,6S)生物利用度低的问题,通过反溶剂沉淀法构建玉米醇溶蛋白-酪蛋白酸钠纳米颗粒(zein-sodium caseinate nanoparticles,ZCP)作为6S的纳米输送载体,对其进行物化性质表征,并通过体外模拟消化、Caco-2细胞模型及大鼠药代动力学实验考察其生物利用度。利用激光粒度仪、透射电子显微镜、傅里叶变换红外光谱对所构建6S复合纳米颗粒(ZCP-6S)的粒径分布、微观形态、化学结构进行表征。结果表明,纳米颗粒呈球形,粒径较小且分布均匀,6S可能通过非共价键与玉米醇溶蛋白相互作用。体外模拟消化结果表明,ZCP-6S的制备使6S的生物可及性提高至(75.34±9.82)%。ZCP-6S显著增强了Caco-2细胞对6S的摄取及转运,处理4 h后,细胞摄取量增加了(0.36±0.06)μg/mg;Caco-2细胞模型下室中6S的质量浓度增加了(1.06±0.06)μg/m L。大鼠药代动力学研究结果表明,纳米颗粒封装后6S的相对口服生物利用度提高了2.28倍。综上,通过玉米醇溶蛋白纳米颗粒输送载体的构建,使6S的生物可及性、细胞吸收和口服生物利用度均得到了有效提高。

Fabrication and catalytic behavior of hierarchically-structured nylon 6 nanofiber membrane decorated with silver nanoparticles

A hierarchically‐structured nylon 6 (PA6) nanofiber membrane decorated with silver nanoparticles (Ag NPs) was fabricated by electrospinning and impregnation methods. The as‐fabricated hierarchically‐structured Ag/PA6 nanofiber membrane (HS‐Ag/PA6 NM) exhibits a morphology in which Ag NPs are deposited on the surfaces of both thick fibers and thin fibers. The content and size of theAg NPs can be controlled by varying the concentration of the silver colloid solution. Compared with the non‐hierarchically‐structured Ag/PA6 nanofiber membrane, HS‐Ag/PA6 NM has a higher specificsurface area and exhibits a higher degradation rate for methylene blue of 81.8%–98.1% within2 h. HS‐Ag/PA6 NM can be easily recycled and exhibits good reusability. It retains a degradation rate for methylene blue of 83.5% after five consecutive cycles. The hierarchically‐structured nanofiber membrane is therefore a potential nanocatalyst.

基于Fe_(3)O_(4)磁分子印迹纳米粒子比色检测蔬菜中6-苄氨基腺嘌呤残留

[目的]实现蔬菜中6-苄氨基腺嘌呤(6-BA)残留的快速、灵敏、可视化检测。[方法]基于Fe_(3)O_(4)磁分子印迹纳米粒子(Fe_(3)O_(4)MMIP NPs)的类过氧化物酶活性和特异识别性,构建了一种简单、快速、高选择性检测6-BA的比色方法,并用于蔬菜中6-BA残留检测。[结果]在pH 4.0、H 2O 2浓度0.02 mol/L、TMB浓度0.02 mol/L和反应时间5 min时,Fe_(3)O_(4)MMIP NPs表现出最佳的类过氧化物酶催化活性。6-BA在1~300 ng/mL质量浓度范围内与空白和样品吸光度值的差值呈良好的线性关系,检测限为0.697 ng/mL。该方法被成功应用于蔬菜(黄瓜、西红柿、黄豆芽、绿豆芽)中6-BA残留检测,回收率为83.47%~106.76%,相对标准差为0.37%~5.66%。此外,4℃下,Fe_(3)O_(4)MMIP NPs贮存60 d后仍能保持良好的催化活性。[结论]基于Fe_(3)O_(4)MMIP NPs检测6-BA的比色方法具有简便、快速、经济等优势,能够用于蔬菜中6-BA残留检测,具备一定的可靠性和实用性。

Microstructure and abrasive wear behaviour of anodizing composite films containing Si C nanoparticles on Ti6Al4V alloy

Anodized composite films containing Si C nanoparticles were synthesized on Ti6Al4 V alloy by anodic oxidation procedure in C4O6H4Na2 electrolyte. Scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS) and X-ray photoelectron spectroscopy(XPS) were employed to characterize the morphology and composition of the films fabricated in the electrolytes with and without addition of Si C nanoparticles. Results show that Si C particles can be successfully incorporated into the oxide film during the anodizing process and preferentially concentrate within internal cavities and micro-cracks. The ball-on-disk sliding tests indicate that Si C-containing oxide films register much lower wear rate than the oxide films without Si C under dry sliding condition. Si C particles are likely to melt and then are oxidized by frictional heat during sliding tests. Potentiodynamic polarization behavior reveals that the anodized alloy with Si C nanoparticles results in a reduction in passive current density to about 1.54×10-8 A/cm2, which is more than two times lower than that of the Ti O2 film(3.73×10-8 A/cm2). The synthesized composite film has good anti-wear and anti-corrosion properties and the growth mechanism of nanocomposite film is also discussed.

A Novel Urine Method for the Diagnosis of Active Tuberculosis by Immunoassay for the Detection of ESAT-6 Using Hydrogel Nanoparticles in HIV Patients

Background: In patients with HIV, conventional tests are of low sensitivity;therefore, a new diagnostic test with hydrogel nanoparticles with reactive blue dye is proposed, which allows the capture, conservation and concentration of ESAT-6 in urine. NIPAs are copolymers that capture low molecular weight proteins and protect against enzymatic degradation. Using an immunoassay, it is possible to detect and quantify ESAT-6 present in urine as a possible marker of active TB. Design/Methods: Study in Lima, Peru, HIV+ participants, ≥18 years with and without tuberculosis (TB). Smear microscopy, culture in solid medium and urine immunoassay were performed. The reference was the diagnosis of TB by radiological or clinical microbiological criteria (indication for TB treatment). There were 2 preanalytical processes: untreated and treated urine (centrifuged, heated), then incubation with NIPAm. After washing, elution, sonication, heat and centrifugation, the final eluate was obtained. This was placed on nitrocellulose membranes, which by means of fixation and incubation processes with anti-ESAT-6 and anti-IgG antibodies, revelation with C-DiGit® Blot Scanner and FluorChem R FR0001. Calibration curves were included in the membranes, density was measured using Image J software. ROC curves, sensitivity and specificity were obtained. Results: The result by groups was HIV+ patient: ROC: 0.75, cut-off point ≥24.06 ng/ml, sensitivity 76.32%, specificity 68.89%, patients ≤200 cells CD4 mm3/ml, ROC: 0.78, cutoff point ≥26.20 ng/ml, sensitivity 75.86%, specificity 71.88%, patients >200 CD4 mm3 cells/ml, ROC: 0.73, cutoff point ≥24.6 CD4 mm3/ml, sensitivity 73.68%, specificity 73.68%. Conclusions: The ESAT-6 detection assay using NIPAm was effective, with higher rates in patients with ≤200 CD4 cells/mm3, the test being more sensitive than smear and culture, but less specific.

Preparation of porous polyamide 6(PA6)membrane with copper oxide(CuO)nanoparticles selectively localized at the wall of the pores via reactive extrusion

In this study,CuO nanoparticles are pre-modified with styrene-maleic anhydride copolymers(SMAs)of different molecular weights and MAH contents.Then the pre-modified CuO nanoparticles(CuO-SMAs)are added to the PA6/SEBS(Styrene Ethylene Butylene Styrene copolymer)(40/60 wt/wt)polymer blends with a co-continuous morphology.When SMA3(MAH=8 wt%,M_(n)=250000 g/mol)is used to modify CuO nanoparticles,and the grafting degree of SMA3 on the surface of CuO reaches 2.74 wt%,90.71%of the added mCuO-SMA3 nanoparticles can be located at the interface of PA6 and SEBS.A porous PA6 membrane with CuO nanoparticles located at the pore walls can be obtained after the SEBS phase is etched with xylene.The catalytic reaction velocity constant(k)for the reduction of p-nitrophenol in NaBH_(4)solutions with the PA6/mCuO-SMA3 porous membrane can reach 1.0040 min^(-1).This work provides a feasible and straightforward method for the preparation of porous polymer membranes with functional nanoparticles located at the wall of the pores.

Voltammetric Determination of Vitamin B6 at Glassy Carbon Electrode Modified with Gold Nanoparticles and Multi-Walled Carbon Nanotubes

In this work, the gold nanoparticles (Au NPs)/multi-walled carbon nanotubes (MWCNTs) composite film modified glassy carbon electrode (GCE) was fabricated, and scanning electron microscopy (SEM) was used to investigate the assemble process of the composite film. In pH 7.0 PBS, a oxidation peak of the vitamin B6 (VB6) was only observed at composite film modified electrode. Under the optimized conditions, the current intensity was linear with the concentrations of VB6 in the range of 1.59 to 102.74 μg●mL–1 with a detection limit of 0.53 μg●mL–1 (S/N = 3). The modified electrode had been applied in medication analysis, and obtained good results.

Synergistic enhancement of ultrasound therapy for tumors using hypoxia-activated 6-diazo-5-oxo-L-norleucine(DON)prodrug nanoparticles

Ultrasound(US)has been applied in clinical practice for its non-invasive and high selectivity.However,it is difficult to achieve a satisfactory anti-tumor effect with US alone.Meanwhile,the use of US therapy alone can exacerbate tumor hypoxia.In this study,we prepared hypoxia-activated 6-diazo-5-oxo-L-norleucine(DON)prodrug nanoparticles(HDON-NPs)to improve US therapeutic effects.In an H22 murine liver cancer model,US therapy selectively disrupted tumor blood vessels,leading to increased tumor hypoxia and a 1.67-fold increase in the expression of nitroreductase(NTR).The combination therapy of US and HDON-NPs demonstrated a synergistic effect,resulting in a tumor suppression rate(TSR)of 90.2%±6.4%,which was 5.93-fold higher than that of US therapy alone.The combined treatment selectively blocked the glutamine metabolism of the tumor cells while simultaneously activating the T cells in the tumor microenvironment,thereby exerting a robust anti-tumor effect.

Efficient charge relay steering in Pd nanoparticles coupled with the heterojunction for boosting CO_(2)photoreduction to C_(2)H_(6)

Solar-driven CO_(2)conversion to prepare value-added products is highly desirable but challenging.Central to the achievement of multi-carbon products via CO_(2)photoconversion is to break the bottlenecks of C-C coupling and multi-electron transfer.Herein,a charge relay system consisting of Pd-decorated BiOCl-wrapped CuBi_(2)O_(4)is reported by taking advantage of the synergy of Pd nanoparticles(PdNPs)and heterojunction for efficient CO_(2)-to-C_(2)H_(6)photoconversion.The C_(2)H_(6)production rate reached 167.1µmol g^(-1)h^(-1)with the electron selectivity of 81.1%in the absence of any sacrificial agents.The spectroscopic characterizations indicated that BiOCl nanosheets,acting as the charge relay,directionally transferred the photogenerated electrons from itself and CuBi2O4 nanorods to PdNPs for C-C coupling.The coordinated ensemble of PdNPs and heterojunction significantly elevated the charge separation and transfer efficiency.Moreover,the in-situ spectroscopic analysis supported by theoretical simulations demonstrated that the electron-rich PdNPs generated by the charge relay of PdNPs and heterojunction optimized the CO_(2)-to-C_(2)H_(6)reaction pathway and reduced the energy barrier of the key*CHOCO intermediates.This work develops an innovative strategy to design the multifunctional catalysts for the photoconversion of CO_(2)to value-added carbon products.

Nonuniform Distribution of Capping Ligands Promoting Aggregation of Silver Nanoparticles for Use as a Substrate for SERS

Citrate-reduced silver nanoparticles (Ag-NPs) are used extensively for surface-enhanced Raman scattering (SERS) studies, but are typically found to aggregate using an aggregation agent. This study is aimed at developing a simple, stable, and reproducible aggregated method for Ag-NPs without any aggregation agents in aqueous solutions. The aggregation is induced by the process of centrifugation, water washing and ultrasonication. A mechanism based on the nonuniform distribution of capping ligands is proposed to account for the aggregated structure formation. UV-Vis-NIR extinction spectra and TEM allowed us to identify the existence of Ag-NPs aggregation. Further, due to the polydisperse mixture of Ag-NPs (20~65 nm) used in the present work, Ag-NPs are aggregated closely, which contribute to the observation of low-concentration SERS from the residual citrate layer or even the single-molecule SERS of R6Gon aggregation. After the evaporation of droplet of Ag-NPs aggregation on the Si substrate, citrate or R6Gcould also be detected but with marked redor blue-shifts.

静电纺PA6/Ag复合纤维毡的制备及其结构与性能

采用静电纺丝法制备了含纳米Ag颗粒的聚酰胺6(PA6)复合纳米纤维毡,用扫描电子显微镜(SEM)、X射线衍射(XRD)、热分析(TG-DTG)等测试手段分析了纤维的形态与微观结构,并测试了纤维毡对金黄色葡萄球菌的抑菌性。研究发现,随纳米Ag质量分数的增加,纤维的结晶度和热稳定性都得到了一定程度的提高,并且表现出了优异的抗菌性能,有望在防护、过滤和医用领域得到应用。

原位合成Au/泡沫镍磁性基底用于表面增强拉曼快速检测血清中免疫抑制剂代谢物

该文采用处理后的泡沫镍为反应模板,直接还原氯金酸溶液,经实验条件优化,原位制备了纳米金-泡沫镍多孔磁性复合表面增强拉曼散射(SERS)基底(Au-NFs)。泡沫镍三维网状具有大的比表面积和粗糙度,可稳定负载纳米金,通过Au—S键化学吸附更多的目标分子6-巯基嘌呤。复合基底的磁特性易于磁分离富集,避免血液共存物对SERS检测6-巯基嘌呤的干扰。利用磁场诱导纳米金-泡沫镍聚集,可进一步优化纳米金局域等离子场分布,形成SERS热点,大大提升了分析灵敏度,对于探针分子4-巯基吡啶的检出限可达5×10^(-9)mol/L。在外磁场优化条件下,基于Au-NFs复合SERS基底定量检测6-巯基嘌呤,在5×10^(-7)~1×10^(-8) mol/L浓度范围内有良好的线性,检出限为1×10^(-9) mol/L。该Au-NFs基底无需样品预处理,可实现血清中6-巯基嘌呤的快速分析,加标回收率在92.8%~107%范围内,表明方法可靠。

(PtI_6-2RDG)_n缔合纳米微粒体系的共振散射、荧光猝灭和减色效应研究

在 0 .0 2mol LHCl介质中 ,罗丹明 6G(RDG)分别在 5 30nm和 5 5 0nm处有一个吸收峰和荧光峰 .PtI2 -6与RDG+主要通过静电引力形成疏水性的PtI6 2RDG缔合物分子 .PtI6 2RDG分子间存在较强的分子间作用力和疏水作用力而生成 (PtI6 2RDG) n 缔合纳米微粒 ,其粒径为 40nm ,在 40 0nm、470nm和 5 90nm产生 3个共振散射峰 ,其中40 0nm和 5 90nm处的 2个峰为其特征共振散射峰 .5 5 0nm荧光峰和 5 30nm吸收峰的降低是由于纳米微粒形成后 ,只有裹露在 (PtI6 2RDG) n 纳米微粒界面的RDG荧光分子才能吸收激发光子跃迁到激发态 ,进而返回基态产生荧光 ,而体相的RDG荧光分子无法与激发光作用产生荧光 ,即与激发光作用的RDG分子数大为降低 .当该纳米微粒体系加入乙醇后 ,由于乙醇致使 (PtI6 2RDG) n 纳米微粒分解为PtI6 2RDG分子 ,体系的红紫色和共振散射峰消失 ,吸收峰和荧光峰恢复 .研究结果表明 ,红紫色 (PtI6 2RDG) n 纳米微粒的形成是其共振散射增强、荧光猝灭。

GSH、L-Cys和6-MP诱导纳米金聚集行为的分析与应用

利用纳米金的表面等离子共振吸收光谱研究了谷胱甘肽(GSH)、L-半胱氨酸(L-Cys)和6-巯基嘌呤(6-MP)3种巯基化合物与纳米金作用的机理。结果表明,3种巯基化合物均能诱导纳米金聚集导致其表面等离子共振吸收峰红移。聚集后的纳米金对介质环境(如溶液极性)的变化较敏感,其吸收峰随着加入分析物的极性变化有规律地红移,并且吸光度也线性下降。可根据波长的红移或吸光度变化确立定量关系,可望用于分析对象的定量检测。

Photocatalytic aerobic oxidation of toluene and its derivatives to aldehydes on Pd/Bi_2WO_6

The selective oxidation of toluene and its derivatives is extremely important in the chemical industry.The use of photocatalysis in organic synthesis has attracted considerable attention among synthetic chemists because of its ＂green＂ environmental characteristics.In this study,nanoscale Bi_2WO_6with a flower-like morphology was found to be a highly efficient photocatalyst in the catalytic oxidation of toluene and its derivatives using O_2 as the oxidant.The loading of Pd nanoparticles as a cocatalyst onto the flower-like Bi_2WO_6 was found to produce a significant enhancement in the catalytic activity.Mechanistic investigation showed that the superior performance of Pd/Bi_2WO_6 could be attributed to the improvement of both the reductive and oxidative abilities of Bi_2WO_6 by the loading of the cocatalyst.

Q[6]-Ag纳米的合成及催化性能研究

采用化学还原法,以Q[6]为稳定剂和分散剂,Na BH4为还原剂,在适宜的温度、物质的量比、反应时间下制备Q[6]-Ag纳米颗粒。对产物进行了FT-IR、XRD、TEM等表征。结果表明制备的Q[6]-Ag中纳米颗粒呈球状,粒径25nm。Q[6]-Ag纳米颗粒对次甲基蓝的催化效果表明:在H2O2辅助下,Q[6]-Ag(Q[6]与硝酸银物质的量比1∶1)对次甲基蓝有良好的催化效果。

基于纳米金探针的光度法测定痕量6-巯基嘌呤

在p H 5.5的B-R缓冲溶液中,6-巯基嘌呤与纳米金反应后,纳米金粒子溶液的颜色由酒红色逐渐变为蓝色,其最大吸收波长从525 nm移至670 nm.670 nm和525 nm处吸光度的比值(A670/A525)与6-巯基嘌呤的浓度呈正比.据此,在优化实验条件下,建立纳米金分光光度法测量痕量6-巯基嘌呤的新方法 .该方法准确度高、灵敏度好.

反应挤出制备硫化镉/尼龙6纳米复合材料

采用反应挤出工艺双原位法制备硫化镉/尼龙6（CdS/PA6）纳米复合材料。CdS/PA6纳米复合材料由硫镉矿型CdS和粘均分子量在（2.4-5.6）×10^4 g/mol的尼龙6基体组成。低CdS含量时,纳米CdS晶体（6.2-9.7 nm）聚集形成15-50 nm的松散的团聚体,均匀的分散于尼龙6基体。较高CdS含量时,CdS/PA6纳米复合材料总体分散性较好,但存在一些由纳米CdS晶体融合成的紧密的团聚体（约100 nm）。将含14.1%（质量分数）CdS的CdS/PA6纳米复合材料用作色母料与商品尼龙6树脂熔融共混,可以生产出颜色均匀、色差极低的黄色制品。