Quantum dots (QDs) have been widely studied in both basic sciences and applications for many years.1,2 In comparison with organic dyes, QDs have many advantages, including tunable sizedependent emission, high photoluminescence (PL) quantum yields, broad excitation spectra and narrow emission bandwiths.3 The semiconductor QDs have been intensively investigated in versatile applications, including thin-film light emitting devices (LEDs),4 low-threshold lasers,5 optical amplifier media for telecommunication networks6,7 and biological labels.8-10

During a consensus conference in 1986, a definition was given for biomaterials. Indeed, a biomaterial is «a non-living material used and designed to be integrated with biological systems». Biomaterials are defined according to their domain of use and regroup metals and alloys, ceramics, polymers3.

Binary coalescence of water drops in organic liquids has several commercial applications that are related to the stabilization of emulsions. The stability of the emulsion is dependent on adsorption of the surfactant molecules at the water/organic interface. In this work, the adsorption of ionic surfactants at water/organic interfaces, both in the presence and absence of salt, and its effect on binary coalescence were studied. The ionic surfactants used were sodium dodecyl sulfate and cetrimide. The organic phase was constituted from either toluene or carbon tetrachloride. Adsorption was studied by measuring the interfacial tension. The presence of salt had a strong effect on the interfacial tension in the presence of these surfactants. In the absence of surfactant, salt had little effect on interfacial tension. The data were fitted using a surface equation of state that was developed from the Gibbs adsorption equation and the Langmuir isotherm. Binary coalescence of water drops in toluene was studied in a specially designed coalescence apparatus. Coalescence time did not have a single value but a stochastic distribution of coalescence time was observed in each case. The addition of salt had a significant effect on coalescence time. A stochastic model was used to characterize the distributions.

This work presents a study on adsorption characteristics of two anionic (SDS and SDBS) and one cationic (CTAB) surfactants at air–water interface in presence of inorganic salt (NaCl). Coalescence of air bubbles in these solutions is studied by measuring the rest time of air bubbles at flat air–water interface. Significant effects of salt on surface tension and coalescence are observed. Surface tension is reduced in presence of salt and rest time is increased. The stochastic model developed earlier by Ghosh and Juvekar (2002; Chem Eng Res Des, 80: 715–728) fits the rest time distributions very well. A comparison of seven film-drainage models with the mean values of these distributions is presented. It is observed that these models, within the limitations of the simplifying assumptions behind their development, can not predict the values of rest time accurately.

Local chemical grafting of OctadecylTriMethoxySilane (OTMS) on SiO2/Si substrates has been successfully performed on specific micrometric areas by combining nano-imprint lithography and Chemical Vapour Deposition (CVD). The optimisation of the CVD experimental conditions using atomic force microscopy has lead to homogeneous 1 μm square arrays of OTMS monolayers on millimetric areas.

In organic field effect transistors, charge transport is confined to a narrow region next to the organic/dielectric interface. It is thus extremely important to determine the morphology and the molecular arrangement of the organic films at their early growth stages. On a substrate of technological interest, such as thermally grown silicon oxide, it has been recently found that R-sexithienyl aggregates made of flat-lying molecules can simultaneously nucleate besides islands made of molecules standing vertical. In this paper, we investigate the effects due to variations in surface chemical composition on R-sexithienyl ultrathin film formation. Flatlying molecules are no longer detected when Si-OH groups present at the surface are chemically removed but also when the Si-OH or Si-H group density is maximized. This gives evidence that variations in the surface chemical composition can largely affect the nucleation and growth processes of organic/dielectric interfaces. We hypothesize that isolated OH groups can interact with R-sexithienyl molecules and anchor them down flat with respect to the surface.

Nanomechanical bending behavior and elastic modulus of silver nanowires
65–140 nm
 suspended across silicon microchannels were investigated using digital pulsed force mode
DPFM atomic force microscopy through coincident imaging and force profiling. Deflection profiles analyzed off-line demonstrate the role of bending nanowire shape and symmetry in experimentally determining boundary conditions, eliminating the need to rely on isolated midpoint bending measurements and the usual assumptions for supported-end behavior. Elastic moduli for as-prepared silver nanowires ranged from 80.4±5.3 to 96.4±12.8 GPa, which met or exceeded the literature values for bulk silver. The calculated moduli were based on classic modeling, both with one-dimensional analytical solutions and three-dimensional finite element analysis. Modeling results indicate that the classic models are accurate as long as the boundary conditions are not arbitrarily assumed but directly confirmed by data analysis. DPFM also facilitated the experimental determination of sample gauge lengths from images and bending profiles.

The conformation of cross-linked, monomolecular, polystyrene nanoparticles on a solid substrate is considered as a function of cross-linking degree and substrate surface free energy. It is found that an extreme amount of cross-linking is necessary for the ca. 5-10 nm diameter nanoparticles to retain their original spherical shape, regardless of surface free energy. A lesser amount of cross-linking produces a nanoparticle that collapses to a pancake-like conformation on a high-energy substrate yet remains spherical on a low-energy surface. A simple model is developed to reveal the relationship between nanoparticle modulus and surface free energy to define the nanoparticle conformation.

The mechanical bending behavior of polymer nanowiresspolypyrrole and poly(3,4-ethylene dioxythiophene- co-styrene sulfonate)sproduced by template molding were measured using a new innovation in atomic force microscopy (AFM). Digital pulsed force mode (DPFM) was used to image and simultaneously perform three-point bend tests along nanowires spanning microchannels in silicon. The bending profiles were analyzed for apparent elastic moduli variations along the suspended length of individually isolated nanowires and compared to classic beam deflection models for various geometric and boundary conditions. The elastic moduli calculated from these AFM data are 2-7 times that expected for bulk polymer values (1-3 GPa), demonstrating an apparent strengthening of nanostructured polymer even for diameters greater than 100 nmsthe accepted boundary for nanoscience. Furthermore, detailed analysis of deflection data versus loading location demonstrates the experimental dependence on test geometry and inherent errors in relying solely on midpoint bending measurements or any single loading configuration for nanomechanical testing as well as the significant contribution of nanoindentation effects.

This paper reports friction-induced formation of nanocrystals on single crystal substrate. Using a pin-on-disk tribometer, a low-melting temperature gallium was slid against single crystal silicon. High resolution TEM results showed that instead of wear, nanometer length scale silicon crystal was formed. The frictional work, eutectic potential, and strain energy density were estimated. There was sufficient frictional energy to melt gallium (Ga) and reach the Ga–Si eutectic temperature. Although it has been reported that friction stimulation induces phase transformation, this work demonstrated the formation of potentially useful nanocrystals, which arose from silicon substrate. © 2005 Elsevier B.V. All rights reserved.

Octadecyltrimethoxysilane
OTMS self-assembled monolayers have been grafted on micrometric and nanometric areas of SiO2 /Si substrates using a process combining nanoimprint lithography and atmospheric chemical vapor deposition. The optimization of the process has lead to monolayer square patterns of OTMS with lateral sizes ranging from 2
m down to 50 nm. Their coverage uniformity extends on several square millimeters. Their coverage density can be accurately tuned by the deposition time. © 2007 American Vacuum Society. DOI: 10.1116/1.2402144

The prevailing conception of carbon nanotubes and particularly single-walled carbon nanotubes (SWNTs) continues to be one of perfectly crystalline wires. Here, we demonstrate a selective electrochemical method that labels point defects and makes them easily visible for quantitative analysis. High-quality SWNTs are confirmed to contain one defect per 4 μm on average, with a distribution weighted towards areas of SWNT curvature. Although this defect density compares favourably to high-quality, silicon single-crystals, the presence of a single defect can have tremendous electronic effects in one-dimensional conductors such as SWNTs.We demonstrate a one-to-one correspondence between chemically active point defects and sites of local electronic sensitivity in SWNT circuits, confirming the expectation that individual defects may be critical to understanding and controlling variability, noise and chemical sensitivity in SWNT electronic devices. By varying the SWNT synthesis technique, we further show that the defect spacing can be varied over orders of magnitude. The ability to detect and analyse point defects, especially at very low concentrations, indicates the promise of this technique for quantitative process analysis, especially in nanoelectronics development.

Atomic force microscopy (AFM) of porphyrin aggregates formed on silica from acidic aqueous solution is used to investigate the basis for the previously reported counterion dependence of the optical spectra of aggregates of H2TCPP2+, the diacid form of tetra(p-carboxyphenyl)porphyrin (TCPP). Resonance light scattering confirms the presence of excitonically coupled porphyrin aggregates in solutions of H2TCPP2+ in both aqueous HCl and HNO3. Aggregates formed in aqueous HNO3 solutions show resonance light scattering (RLS) at wavelengths within both the H and J aggregate absorption bands and are imaged on the surface of silica as nanorods about 3 to 4 nm in height. H2TCPP2+ aggregates in aqueous HCl solution exhibit RLS when excited within the blue-shifted Soret band (H band) and produce AFM images on silica of ring-shaped structures ranging from about 200 to 2000 nm in diameter. Fluorescence excitation and emission spectra reveal quenching of the Q-band emission in the aggregates at a pH less than 1 and confirm the existence of a single species, assigned to a dimer, at a pH just above 1. The morphology of the nanostructures as revealed by AFM provides insight into the structural basis for the counterion-dependent optical properties of H2TCPP2+ aggregates.

An atomic force microscope(AFM) probing system was connected with a ferroelectric test system measurement the polarization histeresis(P-E) curve

We report a force sensor based on a quartz crystal that is used for measuring nanoscale topographic images. The crystal is a length-extensional mode oscillator with a resonant frequency of about 650 kHz. Compared to 33 kHz tuning forks, such crystal sensors have a much higher resonance frequency, which allows for high force sensitivity and a fast response time. The crystal sensor is operated in the shear-force mode, with the probes vibrating parallel to the sample surface. The tip-sample interaction during operation is estimated to be less than 300 pN.

1）AFM的探针针尖表面涂布一层很薄的分子 2）探针接触到金表面 3）在高浓度的水蒸气环境下，探针头与金表面间会有凝聚的水滴(水桥)形成 4）毛细管作用及表面张力的因素，探针与金表面会维持一定的间距 5）分子利用凝聚的水滴作桥梁，由探针移至金表面 6）探针可不停的移动并在金表面形成一自组装的单层膜

NSCRIPTORTM是一种专注于纳米制造的工具，有利于创造性的科研工作者设计和制备一般技术难以达到的纳米结构。能够实现这种纳米结构的技术便是Dip-Pen纳米平版印刷术(Dip Pen NalithographyTM，简称DPN)。该技术由美国西北大学的Prof. Mirkin研究小组所开发。DPN是一种简单方便的从AFM针尖到基底传输分子的方法，其分辨率可与电子束刻蚀等方法相比，对纳米器件的功能化更为有用。其基本原理图如图1。用AFM的针尖作“笔”，固态基底作“纸”，能与基底有化学作用力的分子作“墨水”，分子通过凝结在针尖与基底间水滴的毛细作用直接“书写”到基底表面。

美国西北大学的Mirkin研究小组开发的"浸沾笔纳米图形制作技术"（DPNTM－Dip Pen Nanolithography）用AFM的针尖作“笔”，固态基底作“纸”，能与基底有化学作用力的分子作“墨水”，分子通过凝结在针尖与基底间水滴的毛细作用直接“书写”到基底表面。

In roughly 20 years the atomic force microscopes moved from an esoteric invention to a routinely used tool for nanotechnology research and development. The AFM is credited with enabling many of the nanotechnology advancements in science and engineering. The AFM has applications in almost all science and engineering disciplines ranging from metrological measurements to visualizing nanostructures.

Introduction Rapid development of quantitative LC-MS/MS assays for bioanalytical application is often slowed down by memory effects due to ion scattering in the mass spectrometer, following optimization by infusional analysis at high analyste concentrations. This can be particularly problematical for drugs with detection limits in the sub ng/mL range, where it may take several hours for background levels decline to acceptable levels. Use of high LC flow rate can also cause high chemical background due to inefficient desolvation, which over time, can cause system contamination necessitating maintenance and interrupt the continuous operation of the mass spectrometer that is required for high throughput analysis. Here, we evaluated the application and performance a new high signal-to-noise atmospheric pressure interface, HSID. This new interface very effectively focuses target analyte ions through orthogonal sampling, such that memory effects are minimal. In addition, it has been designed to improve sensitivity at high LC flows by reducing background chemical noise, through better desolvation by using energy transfer of heated gas as ions flow through moderate pressure laminar flow regions of the interface.

In this report the performance of the IONICS interface for EP10+ and API3000, HSID(Hot Source Induced Desolvation) is compared to the standard EP10+ and API4000 LC/MS/MS instruments.

当今，粘度已经成为工业生产中人们非常关注的一个特性。由于它与生产过程中的材料性能相关，所以将直接影响生产过程的控制和质量控制。 粘度测量多种方法。然而，即使有许多的测量工具，它们都存在同一个致命缺点，即样品与测量工具产生接触，且无法实现高达2000C的高温测量。因此，GBX开发出基于悬滴法的高温粘度测量仪器，以测量玻璃，金属和半导体的高温粘度。

随着科技的进步，大众对于生活质量的要求日益提高，以至于科学家与工程师更依赖于致力提高产品的外观或一些特定的表面性质的研究，以创造其整体的高附加价值。这使得吾人对于物质表面性质的研究工作比以往更加细腻，说明表面科学(Surface Science)对现代应用科学的重要性，刻正不断的提高。

C.M.C的确定在科研与工业生产中的应用极为广泛。 事实上，C.M.C就是当继续添加表面活性剂时，表面张力不再发生变化时的溶液浓度。 这正是C.M.C测量成为所有表面活性剂研究当中最有重要意义的原因，此时，它给出了表面张力尽可能低时所需添加的最少表面活性剂，从而产生巨大的作用和经济效益。

粉末润湿性的应用非常广泛，如：  制药工业：药物粉末在水中的润湿性（或其它溶剂）  水泥工业：水泥的润湿性研究  合成工业：如熔融多聚物与玻璃、铁或者大理石的润湿性（3S表面张力仪的最高温度可达200°C） 而且，使用ILMS我们也可测量纤维的润湿性、液体的表面张力、固体表面能、动态接触角、全自动CMC测量和液体的密度等。

Contact angle measurements can determine the surface energy, , of a solid. To accurately measure the surface energy, we must use a set of fluids and the Lewis acid/base theory with the contact angles, q, for each fluid. However, a simple contact angle measurement with water will give an approximate answer. This is useful because almost all "contaminants" on a surface affect the measured surface energy. This connection is what we exploit when using contact angles.