单晶硅晶格间距的测量技术进展及应用

单晶硅晶格间距是许多重要物理常数测量的基础。本文介绍了硅晶格间距测量技术的发展历程,包括X射线干涉仪直接测量和晶格比较仪间接测量两种方法,以及影响测量结果不确定度的关键因素。得益于晶格间距测量的进展,在纳米尺度,硅晶格间距被国际计量局(BIPM)批准成为新的米定义复现形式。最后介绍了硅晶格在计量学中的应用,以及基于硅晶格实现纳米几何量测量的溯源体系的研究趋势。     

冶金法生产太阳能级硅的除硼方法、技术及工艺

太阳能作为一种绿色可再生能源受到了广泛关注,而杂质去除是从冶金级硅中获得太阳能级硅所需的纯化过程,对硅基太阳能电池的制备至关重要。冶金法制备太阳能级多晶硅新工艺技术由于其能耗低、成本低和污染少等优点,成为研究开发的热点,但如何有效地去除硼是我们面临的最严峻的挑战之一。本文综述了硼的热力学和动力学性质(溶解度、扩散率、扩散系数、传质系数和活度系数)以及近年来除硼的相关课题研究(吹气、炉渣处理、等离子体处理、酸浸和溶剂精炼)。研究发现,溶剂精炼是一种很有前途的获取高纯硅的方法,硅的富集率以及硼的去除率均可达到90%以上,而添加剂能够加强硼化物的形成和析出来改进除硼工艺,且后续几乎可被完全消除,不会对精炼硅造成污染,这将更加有效除硼并增加工艺实用性。最后本文对几种除硼工艺进行了比较分析,并对冶金法的应用前景进行了展望。     

Effect of sodium dodecyl sulfate on CO2 and H2S absorption enhancement of functionalized multiwall carbon nanotubes in water: Experimental study and empirical model

A single bubble absorption column was used to examine the effect of hydrodynamic on carbon dioxide (CO₂) and hydrogen sulfide (H₂S) absorption in pure water and water-based nanofluids dispersed with neat, and OH and NH₂ functionalized multiwall carbon nanotubes (MWCNTs). Sodium dodecyl sulfate (SDS) was used as a surfactant and stabilizer. The maximum absorption of CO₂ and H₂S were found to be 0.0038 mmol/m²·s and 0.056 mmol/m²·s using NH₂-MWCNTs /nanofluid with 0.5 wt% content, respectively. The diffusion coefficients of gases into the nanofluids were computed by using an equation attained based on Dankwert’s theory. A last, an empirical correlation was proposed to determine the Sherwood number for the absorption of the aforementioned gases into the nanofluids.     

Nanocomposite thin film structures based on polyarylenephthalide with SWCNT and graphene oxide fillers

Investigations of nanocomposite thin films based on polyarylene- phthalide, single-walled carbon nanotubes and graphene oxide have been carried out. Using these films as a transport layer, field-effect transistors were assembled and their output and transfer characteristics were measured. The mobility of charge carriers was estimated and the obtained values are as follows: μ_PAP/GO = 0.020 cm² V^?1 s^?1 and μ_PAP/SWCNT = 0.071 cm² V^?1 s^?1.     

Facile synthesis methodology and characterization studies of silica-decorated hybridized anisotropic nanotubes and nanosheets

Carbonaceous nanomaterials and their derivatives have been inspired tremendous enthusiasm in the scientific community. They have been excogitated as the encouraging attributes and the qualified dispersed phase to develop multi-functional composites. Particularly, graphene and carbon nanotube (anisotropic fillers) have gained substantial research interest owing to their promising characteristics. This highlights an innovative technique to synthesize hybridized nanotube and nanosheet. Initially, parent materials have been synthesized: The pristine CNT has been modified by acid mixture solution, and reduced graphene oxide has been prepared by chemical reduction method. Henceforth, the self-assembly in situ sol–gel technique has been endorsed here. The synthesized nanohybrids have been characterized by different spectroscopic techniques: FTIR, Raman, UV, and XPS to confirm the attachment of multifunctionalities; meanwhile, the composition and stability have been investigated from XRD and TGA plots. The magnitude of surface charge and particle size distribution have been evaluated for the parent and hybridized products; further, morphology of all the samples has been authenticated from FESEM and TEM.     

Construction and application of carbon nanotube/polypyrrole-based bacterial surface imprinted sensorEI北大核心CSCD

A simple and fast "non-hole" bacteria surface imprinted (SPBIP) impedance sensor was constructed for ultrasensitive detection of Salmonella. The SPBIP sensor was prepared by one step electropolymerization of pyrrole (functional monomer), single-walled carbon nanotube (SWNT, nano-modulator), and Salmonella(template) onto a glassy carbon electrode. After removing the bacterial template, "non-hole" imprinted sites were formed on the surface of the polymer matrix, allowing the target bacteria to be specifically recognized. The resulting changes in the electrode surface impedance could be used to detect the target bacteria. The effects of the amount of SWNT, polymerization cycles, eluents, elution time and recognition time on the recognition ability of the sensor were investigated. Under the optimal conditions, the sensor could be used to detect 10~1×107 CFU/mLSalmonella with the limit of detection of 3.5 CFU/mL. The sensor could be used for the detection of salmonella in drinking water and orange juice samples with the recoveries ranging from 95.4% to 109.5%. © 2023, Youke Publishing Co.,Ltd. All rights reserved.     

Rich-defect carbon nanotubes for highly sensitive detection of Dopamine

Dopamine (DA) plays an essential role in the central nervous, renal, hormonal and cardiovascular systems. Various modified carbon nanotubes (CNT)-based dopamine sensors have been reported, but inexpensive, highly sensitive plain CNT-based ones are seldom studied. In this work, a facile and inexpensive CNT-based DA sensor is made by rich-defect multi-walled carbon nanotubes (RD-CNT) via an ultrasound method. The defect and elemental states of the RD-CNT are systematically studied by transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), Raman spectroscopy, X-ray powder diffraction (XRD) and X-ray-photoelectron spectroscopy (XPS). Results show that massive holes and cracks exist in RD-CNT. The level of defects increases from the additional exposed edges. The electrochemical characterizations indicate that the electrochemical sensor has the highest sensitivity of 438.4 μA/(μM ⋅ cm²) among all carbon materials-based DA sensors while well meeting the clinically required detection range and selectivity. The DA sensor was further used to detect live healthy human serum and live PC12 cells with satisfactory results, thus holding great promise for an inexpensive but sensitive DA sensor in practical applications of clinical diagnosis and biological research.     

Electrochemical Affinity Sensors Using Field Effect Transducer Devices for Chemical Analysis

The review presents advances and main challenges of the affinity sensors based on field- effect transistors published during the last five years. The different nanomaterial-based field-effect transistors are classified according to the nature of the nanomaterials, beginning by silicon, the “gold-standard” semiconductor, the gallium nitride semiconductor, the organic semiconductors, the silicon nanowires, the inorganic nanomaterials, the carbon nanotubes and the graphene. Due to its exceptional electrical properties, the main works are devoted to graphene. The obtained analytical performances for the detection of biomarkers, of DNA sequences and of miRNA are listed. The relation between the operational conditions - nature of the nanomaterials, procedure of preparation, choice of the receptor molecule, method of immobilization – and the analytical performance are discussed. The perspective of industrialization of these affinity sensors based on field-effect transistors is discussed.     

Fabrication of poly(ϵ-caprolactone)/paclitaxel (core)/chitosan/zein/multi-walled carbon nanotubes/doxorubicin (shell) nanofibers against MCF-7 breast cancer

In the present study, paclitaxel (PTX), multi-walled carbon nanotubes (MWCNTs), and doxorubicin (DOX) have been simultaneously doped into the poly(ϵ-caprolactone) (PCL)/chitosan/zein core-shell nanofibers to increase its cytotoxicity for MCF-7 breast cancers killing. The physico-chemical properties of synthesized nanofibers were determined by scanning electron microscope, Fourier-transform infrared spectroscopy, tensile strength, and degradation rate determinations. The in vitro release studies demonstrated the sustained release of drugs from core-shell nanofibrous scaffold. The cytotoxicity and compatibility of core-shell nanofibers were investigated by their treating with MCF-7 breast cancer cells and L929 normal cells, respectively. PCL/PTX/chitosan/zein/MWCNTs/DOX core-shell nanofibers containing 1 wt% MWCNTs, 100 μg ml⁻¹ DOX and 100 μg ml⁻¹ PTX had a high biocompatibility with a 84% MCF-7 cancer cells killing. The in vivo studies revealed the synergic effects of MWCNTs and anticancer drugs on the tumor inhibition. This method could be considered as a new way for developing of MWCNTs loaded-nanofibers for cancer treatment in future.     

Highly Sensitive Electrochemical Immunosensor Based on Mesoporous PdPt Nanoparticles Anchored on a Three-dimensional PANI@CNTs Network as Nanozyme Labels

In this study, a novel strategy to amplify electrochemical signals by mesoporous PdPt nanoparticles with core-shell structures anchored on a three-dimensional PANI@CNTs network as nanozyme labels (PdPt/PANI@CNTs) was proposed for the sensitive monitoring of α-fetoprotein (AFP, Ag). First, the mesoporous PdPt nanoparticles prepared by a facile chemical reduction method had excellent biocompatibility with biomolecules, which could capture a large amount of AFP-Ab₂ (Ab₂) and exhibit plentiful pores to entrap more thionine (Thi) into mesoporous PdPt nanoparticles with enhanced loading and abundant active sites. Furthermore, the resulting mesoporous PdPt nanoparticles were abundantly dotted on the surface of a three-dimensional PANI@CNTs network with excellent conductivity and a high specific surface area through the bonding of the amino group to form PdPt/PANI@CNTs nanozyme labels. Most importantly, the as-prepared PdPt/PANI@CNTs nanozyme labels exhibited unexpected enzyme-like activity towards the reduction of hydrogen peroxide owing to the highly indexed facets, enhancing the current response to realize signal amplification. In view of the advantages of nanozyme labels and the involvement of gold nanoparticles (AuNPs, which behave as electrode materials) for the sensitive determination of AFP, the as-developed immunosensor could obtain a dynamic working range of 0.001 ng mL^−1–100.0 ng mL⁻¹ at a detection limit of 0.33 pg mL⁻¹ via DPV (at 3σ). Furthermore, the nanozyme-based electrochemical immunosensor exhibited remarkable analytical performance, which brought about feasible ideas for disease diagnosis in the future.