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1.
Abstract

At the founding of the Society for Photographic Education in 1962, a speaker remarked on the scarcity of books on photography. He noted that while secondary and minor figures in painting, sculpture and the graphic arts were subjects of art historical publications, even the major figures in photography were then barely known. His plea was both prophetic and ironic, for although a flood of books on photography and photographers has issued forth in the twenty-five years since that occasion, there are still no major works on a number of significant photographers. However, despite the fact that many of these publications have been hastily researched and poorly produced, in sum they have expanded our knowledge of photography in several directions: as biographical sources, as aesthetic expression and as social interpretation.  相似文献   

2.
3.
In this study we present an analysis of the research trends in Pakistan in the field of biotechnology for the period 1980–2011. Starting with just 15 publications in 1980 with a negligible annual growth rate for the initial 15 years, the number of publications reached 3,273 in 2011 with an annual growth rate of 22 % for the last 15 years. This growth in publications is studied through factors such as Relative Growth Rate and Doubling Time. A comparison of organizations actively engaged in research in biotechnology is made through factors such as their total publications, total citations, and average citations per paper and indices that determine the quality of publications like h-index, g-index, hg-index and p-index. University of Karachi shows the highest number of publications (2,698), while National Institute of Biotechnology and Genetic Engineering with fewer publications shows the highest average citation per paper (8.07). Agha Khan University however, shows the highest h, g, hg and p indices.  相似文献   

4.
The equations of motion in structural dynamics as well as the corresponding eigenvalue problem are governed by 3 matrices for mass, damping and stiffness of order n which equals the number of degrees of freedom. High-performance eigenvalue-solvers are developed for only pairs A, B of matrices. Nevertheless, to benefit from these solvers, the original eigenvalue problem (λ2 MD+K)x=0 is transformed into a linear eigenvalue representation with only two hypermatrices of double order 2n. Consequently the total numerical effort depends on this order 2n. This paper presents a vectoriteration process which actually works in the original space of order n and which needs no special actions like simultaneous iteration if complex conjugate eigenvalues λ, λˉ with identical norm have to be calculated. The theoretical foundation of this process still goes back to the pair of hypermatrices.  相似文献   

5.
Abstract

The pioneering and vastly influential work by William Ivins Jr, Prints and Visual Communication, has been with us since 1953. Tracing the development of the graphic arts until their supposed apogee with the arrival of photography, Ivins' book is such a monument of original thought that it would take a person with both considerable intellectual courage and determination to challenge it. Professor Estelle Jussim has done just that, with mixed results but with scholarly research of a rare implacability of logic. Taking absolutely nothing for granted, Jussim apparently intended to re-do Ivins entirely by the scientific method, since the former Curator of Prints at the Metropolitan Museum admitted his book was the product of a lifetime of observation written down ‘from memory’.  相似文献   

6.
We investigate the decay of vortices in a rotating cylindrical sample of 3He-B, after rotation has been stopped. With decreasing temperature vortex annihilation slows down as the damping in vortex motion, the mutual friction dissipation α(T), decreases almost exponentially. Remanent vortices then survive for increasingly long periods, while they move towards annihilation in zero applied flow. After a waiting period Δt at zero flow, rotation is reapplied and the remnants evolve to rectilinear vortices. By counting these lines, we measure at temperatures above the transition to turbulence ∼0.6 T c the number of remnants as a function of α(T) and Δt. At temperatures below the transition to turbulence T≲0.55 T c, remnants expanding in applied flow become unstable and generate in a turbulent burst the equilibrium number of vortices. Here we measure the onset temperature T on of turbulence as a function of Δt, applied flow velocity v=v nv s, and length of sample L.  相似文献   

7.
We study Semidefinite Programming, SDP, relaxations for Sensor Network Localization, SNL, with anchors and with noisy distance information. The main point of the paper is to view SNL as a (nearest) Euclidean Distance Matrix, EDM, completion problem that does not distinguish between the anchors and the sensors. We show that there are advantages for using the well studied EDM model. In fact, the set of anchors simply corresponds to a given fixed clique for the graph of the EDM problem.  相似文献   

8.
Editorial     
Abstract

In the history of photography the earliest years are represented by a comparatively small number of people, remembered not only for their excellence, but often because their work features with some regularity in international salerooms. It is therefore gratifying to be able to introduce a new name onto the scene who was highly regarded by his contemporaries, and was at the same time related, by marriage, to William Henry Fox Talbot, the centenary of whose death we are remembering this year. That John Dillwyn Llewelyn should not be widely known today, is perhaps not surprising. Apart from a few photographs that were included in such publications as The Sunbeam, the majority of his existing images have remained in the family.That John Dillwyn Llewelyn should not be widely known today, is perhaps not surprising. Apart from a few photographs that were included in such publications as The Sunbeam, the majority of his existing images have remained in the family.  相似文献   

9.
ABSTRACT

A multi-Gaussian beam model uses a superposition of Gaussian beams to simulate the waves radiated from an ultrasonic transducer. We show that propagation and reflection/transmission laws for Gaussian beams in fluids and elastic solids can be written in the form of A , B , C , D matrices that are analogous to the A, B, C, D scalars used in Gaussian optics. This representation leads to simple expressions for a Gaussian beam even after that beam has been transmitted or reflected at multiple curved interfaces and produces a highly modular multi-Gaussian beam model that is also computationally very efficient. Some examples of the use of this model for both planar and curved interfaces are given.  相似文献   

10.
Context: Salbutamol is a short-acting β2-adrenergic receptor agonist that has been used for many years for relief of bronchospasm. However, studies on the pharmacokinetic profile of orally inhaled salbutamol doses used in clinical practice have not yet been reported in Chinese subjects.

Objective: The aim of this study was to compare the pharmacokinetics and evaluate the bioequivalence of two orally inhaled salbutamol formulations.

Materials and methods: A single-dose randomized fasting two-period, two-treatment and two-sequence crossover open-label bioequivalence study was conducted in 24 healthy Chinese adult male volunteers, with a 1-week washout period between treatments. Plasma concentrations of salbutamol were determined using liquid chromatography coupled to tandem mass spectrometry. Pharmacokinetic parameters, including AUC0–0.33?h, AUC0–24?h and Cmax were calculated and the 90% confidence intervals of the ratio (test/reference) pharmacokinetic parameters were obtained by analysis of variance on logarithmically transformed data.

Results: The mean (SD) pharmacokinetic parameters of the reference drug were AUC0–0.33?h, 227.2 (89.9) pg·h/ml; AUC0–24?h, 2551.9 (1008.0) pg·h/ml; Cmax, 801.3 (307.3) pg/ml and t1/2, 5.14(1.36) h. Those of the test drug were AUC0–0.33?h, 244.0 (104.4) pg·h/ml; AUC0–24?h, 2664.4 (1081.8) pg·h/ml; Cmax, 873.7 (374.4) pg/ml, t1/2, 5.29 (1.23) h. The median value for Tmax was 0.25?h for both formulations. The 90% confidence intervals for the AUC0–0.33?h, AUC0–24?h and Cmax were in the range of 0.892–1.208, 0.876–1.195 and 0.911–1.203, respectively.

Conclusion: This single-dose study found that the test and reference products met the regulatory criteria for bioequivalence of China in healthy Chinese volunteers.  相似文献   

11.

It is known that the H-indexes of individuals, research groups, institutions, scientific journals, and countries strongly depend on the field of study, slowly increase with the number of publications, N, and can be described by empirical power-law functions of the type H?=?C?×?Na (C and a are constants and depend on the specific field being analyzed). In this paper, we use this function and propose a new index [Montazerian–Zanotto–Eckert (MZE)], which is normalized by the number of publications and typically varies from ??1 to +?1, to characterize the relative standing of a research group, institution, or author to those of his/her peer groups. Due to the rich statistics available, as an example, here we analyzed and tested the new parameter against the citation-related performance (H-index) of countries. We found that the MZE index readily distinguishes between countries that stand above or below the average (for any given number of publications). Generally, publications of countries with a positive MZE index are more interesting or visible than the average. Analyzing publication output in this manner instead of the H-index allows for a less biased comparison between researchers, journals, universities, or countries for any particular combination of H-index and publication output.

  相似文献   

12.
Abstract

In this paper, to obtain an analogy between the curved spaces and the linear optics, we expand the idea of Sánchez-Soto and co-workers [Phys. Rep.2012,513, 191; Phys. Rev. A 2011,84, 023830] to the multilayer films. We investigate effects of thickness and index of refraction of the films on the Lorentzian transformations. In addition, by using the multilayer films, we suggest a very simple experimental set-up which can serve as an analogue computer for testing special relativity. Finally, we draw an analogy between the Rindler space, as an example of the curved spaces, and a suitable multilayer film.  相似文献   

13.
We exhibit instances of non-symmetric periodic orbits for the digital filter map, resolving a question posed in the literature as to whether such orbits can exist. This piecewise irrational rotation, depending on a parameter a = 2cos θ, is an isometry of [?1, 1) × [?1, 1) and reflections in the two diagonals are time-reversing symmetries for the map. Symmetric orbits are plentiful and have been much investigated. Each periodic orbit is paired with a symbolic string, from the alphabet {?, 0, +}, arising under iteration of the map because of the presence of a line of discontinuity. We prove the existence of an infinite family of non-symmetric orbits where the period N starts at 29 and increases in steps of 5; they correspond to the strings (+00)5(+?)2 0 N?19. We describe several computer algorithms to find non-symmetric periodic orbits and their symbolic strings and list non-symmetric strings both for a = 0.5, and for N ≤ 100 across the parameter range. Our evidence suggests that non-symmetric orbits, though not plentiful, are characteristic of the dynamics of the map for all parameter values.  相似文献   

14.
Two types of polycyclic quinones condensed with 1,6-methano[10]annulenes as type A: 1,6-methanonaphtho[2,3-c][10]annulene-7,12-dione 5a, and type B: 1,6-methanonaphtho[2,3-c][10]annulene-5,14-dione 18, bis(1,6-methano[10]annuleno[3,4-b; 3,4-g])anthracene-10,21-dione 20, 1,6-methanoanthraceno[2,3-c][10]annulene-5,16-dione 22, 1,6-methanotetraceno[2,3-c][10]annulene-6,17-dione 23, and 1,6-methano phenanthreno[2,3-c][10]annulene-5,6-dione 24 have been synthesized. The acene derivative 6 corresponding to that of 5a was synthesized by the reduction of quinone 5a. The physical, spectral, and chemical properties of these new compounds have been investigated.  相似文献   

15.
Recently, geographical information systems have been very intensively applied in social life and in public health in particular. A retrospective problem-oriented search on their use in health planning was performed in Web of Science of Web of Knowledge, three versions of MEDLINE, Scopus, EMBASE, and ProQuest Medical in 1990–2010. The annual dynamics of a set of scientometric parameters characterizing several aspects of the abstracted publications, authors’ scientific institutions, journals, authors, citations, and languages was comparatively analyzed. It was established that world publication output on such a relatively narrow topic was reflected to a different extent in these data-bases. MEDLINE (PubMed) presented with 484 papers published in 243 journals followed by MEDLINE (WoK) with 360 papers in 215 journals. The abstracted publications were mainly in English, but 14 other languages were present in significant numbers. Publications by authors from 44 countries were abstracted in WoS but from 29 countries in MEDLINE (Ebsco). The most productive authors and institutions as well as the ‘core’ journals were identified. The International Journal of Health Geography occupied the leading position. The Center for Disease Control and Prevention (USA) was one of the most productive research institutions in WoS and in Scopus. Scientific institutions and journals belonged to problem-oriented and to mono-, two- and three-disciplinary thematic profiles as well. Some essential peculiarities of the dynamics of research institutionalization and internationalization in this interdisciplinary field were illustrated. The constellation of specific semantically-loaded indicators could be applied for the purposes of problem-oriented analyses as it could timely identify the essential patterns of scientific advances in rapidly expanding interdisciplinary topics.  相似文献   

16.
The scientific output of major institutions in Thailand was examined from the number of international publications covered byScience Citation Index (SCI), publications inJournal of the Science Society of Thailand (J. Sci. Soc. Thailand) and abstracts presented at the annual symposium of the Science Society of Thailand. A good correlation (r=0.92) was observed between the number of publications covered bySCI and inJournal of the Science Society of Thailand, while a poorer correlation (r=0.73) was observed between the former and the number of symposium abstracts.  相似文献   

17.
This paper focuses the attention on the ch-index, a recent bibliometric indicator similar to the Hirsch (h) index, to evaluate the published research output of a scientist (Ajiferuke and Wolfram, Proceedings of the 12th international conference of the international society for scientometrics and informetrics. Rio de Janeiro, pp. 798–808, 2009). Ch-index is defined as the number such that, for a general group of scientific publications, ch publications are cited by at least ch different citers while the other publications are cited by no more than ch different citers. The basic difference from the classical h is that, according to ch, the diffusion of one author’s publication is evaluated on the basis of the number of different citing authors (or citers), rather than the number of received citations. The goal of this work is to discuss the pros and cons of ch and identify its connection with h. A large sample of scientists in the Quality Engineering/Management field are analyzed so as to investigate the novel indicator’s characteristics. Then, the analysis is preliminarily extended to other scientific disciplines. The most important result is that ch is almost insensitive to self-citations and/or citations made by recurrent citers, and it can be profitably used for complementing h.  相似文献   

18.
The distribution of elements near the Fe3Al/Q235 diffusion bonding interface was computed by the diffusion equation as well as measured by means of EPMA. The results indicated close agreement between the two for iron and aluminium. Diffusion coefficient in the interface transition zone is larger than that in the Fe3Al and Q235 steel at the same temperature, which is favourable to elemental diffusion. The diffusion distance near the Fe3Al/Q235 interface increased with increasing heating temperature,T , and the holding time, t. The relation between the width of the interface transition zone,x , and the holding time,t , conformed to parabolic growth law: x bd2 = 4.8 × 104 exp(-133/RT) bdt -t 0bd. The width of the interface transition zone does not increase significantly for holding times beyond 60 min.  相似文献   

19.
The h-index of h-index and of other informetric topics   总被引:1,自引:0,他引:1  
In this paper we examine the applicability of the concept of h-index to topics, where a topic has index h, if there are h publications that received at least h citations and the rest of the publications on the topic received at most h citations. We discuss methodological issues related to the computation of h-index of topics (denoted h-b index by BANKS [2006]). Data collection for computing the h-b index is much more complex than computing the index for authors, research groups and/or journals, and has several limitations. We demonstrate the methods on a number of informetric topics, among them the h-index.  相似文献   

20.
Multivariate exponentially weighted moving average (MEWMA) control chart with five different estimators as population covariance matrix is rarely applied to monitor small fluctuations in the statistical process control. In this article, mathematical models of the five estimators (S1, S2, S3, S4, S5) are established, with which the relevant MEWMA control charts are obtained, respectively. Thereafter, the process monitoring performance of the five control charts is simulated. And the simulation results show that the S4 estimator-based MEWMA control chart is of the best performance both in step offset failure mode and ramp offset failure mode. Since the inline process monitoring of photovoltaic manufacturing is intended to be a problem of multivariate statistics process analysis, the feasibility and effectiveness of the proposed model are elaborated in the case study during the cell testing and sorting process control for the fabrication of multicrystalline silicon solar cells.  相似文献   

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