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1.
Standardization will play an increasing role in creating a smooth transition from the laboratory to the marketplace as products based on nanotechnology are developed and move into broad use. Traditionally, standards have evolved out of a need to achieve interoperability among existing products, create order in markets, simplify production and ensure safety. This view does not account for the escalating trend in standardization, especially in emerging technology sectors, in which standards working groups anticipate the evolution of a technology and facilitate its rapid development and entrée to the market place. It is important that the nanotechnology community views standards as a vital tool to promote progress along the nanotechnology value chain – from nanoscale materials that form the building blocks for components and devices to the integration of these devices into functional systems.This paper describes the need for and benefits derived from developing consensus standards in nanotechnology, and how standards are created. Anticipatory standards can nurture the growth of nanotechnology by drawing on the lessons learned from a standards effort that has and continues to revolutionize the telecommunications industry. Also, a brief review is presented on current efforts in the US to create nanotechnology standards.  相似文献   

2.
Hoyt (1939) and Firsov devised methods in classical mechanics to deduce a central scattering potential from a measured differential effective cross-section in the nonrelativistic case. These methods are here extended to the relativistic case. A detailed analysis of the applicability of all methods has been undertaken for potentials of the form V(r) = ±r–k for sufficiently high energies of the colliding particles. It is found that Hoyt's method is inapplicable in the relativistic case only when the potential represents attraction. A relatively simple method is given for deducing the parameters and k for a monotonic attraction potential that can be approximated by V(r) = –r–k. The method is based on simple arguments concerning the dimensions of the cross-section. It is sufficient to know only two values of the integral cross-section in the same range of angles but at different energies to determine the parameters.  相似文献   

3.
International strategy for Nanotechnology Research   总被引:3,自引:3,他引:0  
The worldwide nanotechnology research and development (R&D) investment reported by government organizations has increased by a factor of 3.5 between 1997 and 2001, and the highest rate of 90% is in 2001. At least 30 countries have initiated or are beginning national activities in this field. Scientists have opened a broad net of discoveries that does not leave any major research area untouched in physical, biological, and engineering sciences. Industry has gained confidence that nanotechnology will bring competitive advantages. The worldwide annual industrial production is estimated to exceed $1 trillion in 10–15 years from now, which would require about 2 million nanotechnology workers. U.S. has initiated a multidisciplinary strategy for development of science and engineering fundamentals through the National Nanotechnology Initiative. Japan and Europe have broad programs, and their current plans look ahead to four to five years. Other countries have encouraged their own areas of strength, several of them focusing on fields of the potential markets. Differences among countries are observed in the research domain they are aiming for, the level of program integration into various industrial sectors, and in the time scale of their R & D targets. Nanotechnology is growing in an environment where international interactions accelerate in science, education and industrial R & D. A global strategy of mutual interest is envisioned by connecting individual programs of contributing countries, professional communities, and international organizations.  相似文献   

4.
Conclusions The foregoing analysis does not exhaust the analytic methods of laser spectroscopy (see, e.g., [6–8, 142, 143]). The methods of traditional [8–10, 144, 145] resonance [8, 146], and active (or CARS) [8, 11, 147] Raman scattering spectroscopy are continuously being expanded. Newer, purely laser methods — optogalvanic spectroscopy [25, 148], optothermal spectroscopy [7, 149], the method of selective photoionization [6, 150], etc. — are also being developed.Further development of laser spectra analysis will primarily require going beyond narrow laboratory, purely research setups, and the development of commercial laser analytic devices. In this connection, in selecting a method as the basis for the device being constructed it is necessary to know not only the technical characteristics, such as sensitivity, selectivity, speed of operation, etc., but also the metrological characteristics, such as the random and systematic measurement errors; in addition, the measurement accuracy is a decisive factor. At the same time there are few works devoted to the questions of accuracy of the measurements performed with laser spectrometers; in the literature available to us there are no reviews and comparisons of analytic methods of laser spectroscopy from this viewpoint.Amongst the foregoing methods the direct absorption method has the highest accuracy. With a definite arrangement of the measurement process this method enables absolute measurements of the concentration of the analyte component, i.e., it does not require precalibration of the apparatus based on gas mixtures (for the gas analyzer). The minimum achievable error of such measurements is limited by the error of the premeasured absorption coefficient for radiation of the molecule being detected at the wavelength of the laser radiation and at the present time can equal 1–3%. Other methods studied are characterized by higher sensitivity, and they are also more accurate, difficult to calibrate, and less versatile. A comparative analysis of the methods and their errors will be performed in the future.Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 48, No. 1, pp. 7–26, January, 1988.We thank A. P. Voitovich for useful remarks and a discussion of this work.  相似文献   

5.
The Pr content dependence of the bond lengths of Y–Cu, Y–O, O–O, Cu–O, Ba–Cu and Ba–O in PrBa2Cu3Oy are analyzed and discussed in detail. The different valence bonds can be divided into two groups: stable bonds and unstable bonds. Since the bond lengths and angles between every two ions among O2, Cu2 and O3 are very stable, we conclude that the three ions form an unchangeable triangle when the Pr doping changes. The triangle is called “fixed triangle”. This “fixed triangle” can slightly rotate around the Cu2 ions. It is just this rotation that leads to the unstable bonds. As the increase of the Pr content, the bond lengths between the two Cu(2)–O planes becomes larger and larger, the Cu(2)–O planes bend towards the Ba–O plane. The bonds lengths between the Cu(2)–O and Ba–O planes vary oppositely from those of Cu(2)–O, and become shorter and shorter. These changes connected with the superconductivity are discussed.  相似文献   

6.
Special scanning methods applied to line and continuous background cause these to build up according to different laws; a line of unvarying intensity is transformed to a train of video pulses (frequency 50 kc), while the background fluctuations remain purely random. Some characteristics are derived for the autocorrelation function; these enable one to use it to reduce the limit of detection in spectral analysis. The autocorrelation function is reported for the arc determination of Cr at concentrations of 5×10–3, 5×10–4, 5×10–5, and 5×10–6%. Calibration curves are given for these concentrations as determined by photographic and autocorrelation methods. The limit of detection by the photographic method is found to be about two orders of magnitude larger than that for the autocorrelation one.I am indebted to Professor N. A. Prilezhaeva and senior scientist N. G. Preobrazhenskii for valuable advice and discussions, and also to student V. I. Donin for assistance.  相似文献   

7.
The evolution of the phase content and morphology and crystalline defects during temperature and pressure cycling is studied by the methods of transmission electron microscopy and x-ray diffraction analysis. Thermostable Fe–0.12C–1Cr–1Mo–1V steel in the initial ferrite-pearlite state is examined. The evolution of the grain structure and dislocation density is quantitatively described. A low stability of large pearlite grains at temperatures above 600°C is established. The problem of oxidizing of steel of this class is also discussed.  相似文献   

8.
The shift toward online communication in all realms, from print newspapers to broadcast television, has implications for how the general public consumes information about nanotechnology. The goal of this study is threefold: to investigate who is using online sources for information and news about science and nanotechnology, to examine what the general public is searching for online with regards to nanotechnology, and to analyze what they find in online content of nanotechnology. Using survey data, we find those who report the Internet as their primary source of science and technology news are diverse in age, more knowledgeable about science and nanotechnology, highly educated, male, and more diverse racially than users of other media. In a comparison of demographic data on actual visits by online users to general news and science Web sites, science sites attracted more male, non-white users from the Western region of the United States than news sites did. News sites, on the other hand, attracted those with a slightly higher level of education. Our analysis of published estimates of keyword searches on nanotechnology reveals people are turning to the Internet to search for keyword searches related to the future, health, and applications of nanotechnology. A content analysis of online content reveals health content dominates overall. Comparisons of content in different types of sites—blogs, government, and general sites—are conducted.  相似文献   

9.
The crystalline formation of CuInSe2 thin films has been investigated using micro-Raman spectroscopy and AES composition analysis. It is confirmed that the Raman peaks are stongly dependent on the surface morphology and the Cu:In:Se ratio. In the films annealed at 315°C, crystalline grains larger than 2 m show Raman peaks at 174 cm–1 and 258 cm–1. The In content is very low and the Cu:Se ratio is about 1:1 in these grains. The low In concentration is thought to be due to the formation of In2O3 on the surface. On the other hand, random structures of 1–2 m grains found in films annealed at temperatures below 305°C show peaks at 174 cm–1 and 186 cm–1 instead of 258 cm–1 and have a Cu:In:Se ratio of 1:1:3–4. Thus the 186 cm–1 peak is thought to be related to a Cu, In-deficient phase when compared to stoichiometric CuInSe2. The optimum annealing condition was found by analyzing the Raman spectra and composition of different crystalline CuInSe2 grains. Films annealed under this condition exhibited a clear Raman peak at 174 cm–1 and consisted of clusters of crystals less than 1 m in size.  相似文献   

10.
Several of the most common methods for measuring nanoparticle size distributions employ the ultrafine condensation particle counter (UCPC) for detection purposes. Among these methods, the pulse height analysis (PHA) technique, in which the optical response of the UCPC detector is related to initial particle diameter in the 3–10nm range, prevails in applications where fast sampling is required or for which concentrations of nanoparticles are frequently very low. With the PHA technique, white light is required for particle illumination in order to obtain a monotonic relationship between initial particle diameter and optical response (pulse height). However, the popular, commercially available TSI Model 3025A UCPC employs a laser for particle detection. Here, we report on a novel white-light detection system developed for the 3025A UCPC that involves minimal alteration to the instrument and preserves normal counting operation. Performance is illustrated with pulse height spectra produced by differential mobility analyzer (DMA) – generated calibration aerosols in the 3–50nm range.  相似文献   

11.
    
A compact heterodyne receiver system used in the Kuiper Airborne Observatory (KAO) is described. Calibration techniques and methods for eliminating standing wave effects are presented.The J=7–6 rotational transition of carbon monoxide was detected in OMC-1 and in W3 with a beam of 5.5 HPBW.The peak antenna temperature of OMC-1 is 55 K, with the line center at +8±1 kms–1 and FWHM 6.0±0.3 kms–1. The total line flux in our beam is 7.8×10–13 Wm–2. This relatively high value seems to indicate that OMC-1 might be extended over at least several arcminutes in CO (J=7–6).In W3, the peak antenna temperature is 6±2 K, with line center at –42±2 kms–1 and FWHM 9 kms–1. The total line flux is 1.5×10–13 Wm–2. W3 thus emits about 50 L in CO (J=7–6) alone.  相似文献   

12.
Two new derivatives of phosphatidylcholine with an intramolecularly quenched fluorescence, namely, 1––bromoundecanoyl–2–[4–(pyren–1–yl)butyroyl]–sn–glycero–3–phosphocholine (BPPhC) and 1–(9,10–dibromostearoyl)–2–[4–(pyren–1–yl)butyroyl]–sn–glycero–3–phosphocholine (DBPPhC), have been obtained by replacing acyl chains by residual pyrenebutyric and bromine–labeled fatty acids. Their structure has been verified by the 1H–NMR method and the spectral properties have been characterized in media of different polarity with the aid of absorption and fluorescent spectroscopy. It has been established that when BPPhC and DBPPhC are included in liposomes, the intensity of their fluorescence changes markedly as a function of the physical state of the bilayer, which makes it possible to use the compounds obtained as lipid probes for investigating the properties of biological and artificial membranes.  相似文献   

13.
Based on the electronic absorption spectra of Pr3+, Nd3+, Eu3+, Ho3+, and Er3+ ions in 1 M aqueous solutions of chloric acid, calibration graphs have been constructed in a concentration of metals–optical density of a solution format for different frequencies. The band for praseodymium was used at 22,520 cm–1, for neodymium at 17,380, 13,480, and 12,560 cm–1, for europium at 25,380 cm–1, for holmium at 18,580 and 15,580 cm–1, and for erbium at 39,160, 26,480, and 19,160 cm–1. The errors in determining the concentration of the indicated elements as a function of their content have been calculated. It is shown that for perchloric solutions of praseodymium it is possible to correctly determine its contents within the concentration range 0.1–1.5% at a frequency of 22,520 cm–1; for neodymium the ranges are 0.4–1.0, 0.3–1.0, and 0.5–1.0% at 17,380, 13,480, and 12,560 cm–1, respectively; for europium 0.4–1.5% at 25,380 cm–1; for holmium — 0.2–1.5 and 0.4–1.5% at 15,580 and 18,580 cm–1, and for erbium the range is 0.4–1.0% at frequencies of 39,160, 26,480, and 19,160 cm–1.  相似文献   

14.
The development of molecular electronic switching devices for memory and computing applications presents one of the most exciting contemporary challenges in nanoscience and nanotechnology. One basis for such a device is a two-terminal molecular-switch tunnel junction that can be electrically switched between high- and low-conductance states. Towards this end, the concepts of self-assembly and molecular recognition have been pursued actively for synthesizing two families of redox-controllable mechanically interlocked molecules – bistable catenanes and bistable rotaxanes – as potential candidates for solid-state molecular-switch tunnel junctions. This article reviews logically the development and understanding of Langmuir, Langmuir–Blodgett and self-assembled monolayers of amphiphilic bistable and functionalized bistable rotaxanes and their catenanes counterparts. Our increased understanding of the superstructures of these monolayers has guided our recent efforts to incorporate these self-organized molecular switches into devices. The methodologies that are being employed are in their early stages of development. Certain characteristics of the molecules, monolayers, electrodes and devices are emerging that serve as lessons to be consider in responding to the ample opportunities for further research and process development in the field of nanoelectronics. PACS 81.07.-b; 81.07.Nb; 85.65.+h  相似文献   

15.
The paper presents an analysis of regular features of variations in phase composition and atomic volume of the austenite and martensite phases, and the value of Bein's deformation during thermoelastic martensitic transformations versus crystallochemical factors in low-stability alloys based on titanium nickelide doped by different elements (Fe, Co, Rh, Cu, Pd, Pt, Au). It is established that the low-stability alloys undergoing different sequences of martensitic transformations (B2–B19, B2–B19, B2–RB19) demonstrate different values and character of the atomic hopping range during transformation.  相似文献   

16.
In this paper we examine the possibility of testing the equivalence principle, in its weak form, by analyzing the orbital motion of a pair of artificial satellites of different composition moving along orbits of identical shape and size in the gravitational field of the Earth. It turns out that the obtainable level of accuracy is, realistically, of the order of 10–10 or slightly better. It is limited mainly by the fact that, due to the unavoidable orbital injection errors, it would not be possible to insert the satellites in orbits with exactly the same radius and that such difference could be known only with a finite precision. The present–day level of accuracy, obtained with torsion balance Earth–based measurements and the analysis of the Earth–Moon motion in the gravitational field of the Sun with the Lunar Laser Ranging technique, is of the order of 10–13. The proposed space–based missions STEP, SCOPE, GG and SEE aim to reach a 10–15–10–18 precision level.  相似文献   

17.
To assess worldwide development of nanotechnology, this paper compares the numbers and contents of nanotechnology patents in the United States Patent and Trademark Office (USPTO), European Patent Office (EPO), and Japan Patent Office (JPO). It uses the patent databases as indicators of nanotechnology trends via bibliographic analysis, content map analysis, and citation network analysis on nanotechnology patents per country, institution, and technology field. The numbers of nanotechnology patents published in USPTO and EPO have continued to increase quasi-exponentially since 1980, while those published in JPO stabilized after 1993. Institutions and individuals located in the same region as a repository’s patent office have a higher contribution to the nanotechnology patent publication in that repository (“home advantage” effect). The USPTO and EPO databases had similar high-productivity contributing countries and technology fields with large number of patents, but quite different high-impact countries and technology fields after the average number of received cites. Bibliographic analysis on USPTO and EPO patents shows that researchers in the United States and Japan published larger numbers of patents than other countries, and that their patents were more frequently cited by other patents. Nanotechnology patents covered physics research topics in all three repositories. In addition, USPTO showed the broadest representation in coverage in biomedical and electronics areas. The analysis of citations by technology field indicates that USPTO had a clear pattern of knowledge diffusion from highly cited fields to less cited fields, while EPO showed knowledge exchange mainly occurred among highly cited fields.  相似文献   

18.
The half-width of the spectrum of Raman scattering (RS) of the first order of a diamond single crystal grown in a nickel-free system containing nitrogen getters is identical to all growth sectors (1.69 ± 0.02 cm–1). The sectorial inhomogeneity is not reflected in the transmission spectra and birefringence of this crystal. The nitrogen concentration is 4·1017 cm–3. For different growth sectors of the diamond crystal grown in the Ni–Fe–C system, the half-width of the Raman line varies from 1.74 to 2.08 cm–1, differences in the transmission spectra and birefringence are observed, and photoluminescence is revealed. The concentration of nitrogen in the growth sectors {001} is 1.6·1019 cm–3, the content of nickel is estimated to be at a level of 1019 cm–3, and the content of nitrogen in the {¯111} sectors is 4·1019 cm–3.  相似文献   

19.
Using the semiempirical method of partial neglect of differential overlap (PNDO), we have calculated the wave functions, energies, orbital configurations of electronic states, oscillator strengths of transitions, electronic density distributions, and dipole moments for the molecule of biologically active 8–azagona–12,17–dione, containing a conformationally rigid –acyl––aminovinylcarbonyl fragment. It has been established that as to their orbital nature the excited lower and higher singlet electronic states of this molecule are of the n*– and * type respectively. The results of the theoretical analysis are in good qualitative agreement with the spectral data on absorption and luminescence. The calculations of the intermolecular interaction of the compound under consideration with a medium show that the molecular systems under consideration can possess a dynamic multicenter structure.  相似文献   

20.
The nature of the luminescence of zinc sulfide in the spectral range (360), 380–420 nm (SAL) at 80K is analyzed. It is shown that the appearance of SAL radiation is accompanied by additional absorption in the region (350) 365–370 nm at 80K. The low-temperature spectra of sphalerite, exposed to different radiation and subjected to different treatment, are studied. The multiband luminescence of the isoelectronic sulfur impurity in ZnO deposits in the region 383–640 nm is discussed. It is concluded that SAL luminescence is attributable to the localization of excitons in ZnS on clusters, whose formation precedes the precipitation of the ZnO·S phase. The formation of oxygen clusters and deposits on dislocations in ZnS is studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 60–66, February, 1987.  相似文献   

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