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1.
Frank Greenaway 《Endeavour》1979,3(4):138-143
There are many kinds of great men. Berzelius was one, but he was not a Newton, an Einstein, or a Faraday. He set up no world system, he carried out no radical transformation of ideas, he opened up no new vistas through epochmaking experiments. Yet he gathered the whole of the science of chemistry into his intellect, digested it, influenced it in every branch, gave it a notation as elegant as that of music, inspired the next generation, and was superseded by it. He was right more often than he was wrong, and his creative conservatism gave chemistry a discipline it still possesses. 相似文献
2.
Capillary wave phenomena are challenging to study, especially for microfluidics where the wavelengths are short, the frequencies are high, and the frequency distribution is rarely confined to a narrow range, let alone a single frequency. Those that have been studying Faraday capillary waves generated by vertical oscillation have chosen to work at larger scales and at low frequencies as a solution to this problem, trading simplicity in measurement for issues with gravity, boundary conditions, and the fidelity of the subharmonic capillary wave motion. Laser Doppler vibrometry using a Mach–Zehnder interferometer is an attractive alternative: The interface’s motion can be characterized at frequencies up to 40 MHz and displacements of as little as a few tens of picometers. 相似文献
3.
Ronald Anderson 《Endeavour》2001,25(4):157
James Clerk Maxwell's Treatise on Electricity and Magnetism forms one of the major scientific texts of the 19th century, describing the phenomena of electricity and magnetism and the interaction between them. The sources Maxwell acknowledged as the inspiration for his own approach were the Englishman Michael Faraday and his fellow Scotsman William Thomson (later Lord Kelvin). In the Treatise Maxwell presents an approach he maintains was equivalent mathematically to the well established Continental electromagnetism but focused on an action via a medium approach to electromagnetism and located within a British experimental tradition. Exploring these features reveals the Treatise to be in accord with other deep themes in Maxwell's writings, which ground him intellectually and personally in the world of 19th century British Natural Philosophy. 相似文献
4.
Understanding the correlation between exposed surfaces and performances of controlled nanocatalysts can aid effective strategies to enhance electrocatalysis, but this is as yet unexplored for the nitrogen reduction reaction (NRR). Here, we first report controlled synthesis of well-defined Pt3Fe nanocrystals with tunable morphologies (nanocube, nanorod and nanowire) as ideal model electrocatalysts for investigating the NRR on different exposed facets. The detailed electrocatalytic studies reveal that the Pt3Fe nanocrystals exhibit shape-dependent NRR electrocatalysis. The optimized Pt3Fe nanowires bounded with high-index facets exhibit excellent selectivity (no N2H4 is detected), high activity with NH3 yield of 18.3 μg h−1 mg−1cat (0.52 μg h−1 cm−2ECSA; ECSA: electrochemical active surface area) and Faraday efficiency of 7.3% at −0.05 V versus reversible hydrogen electrode, outperforming the {200} facet-enclosed Pt3Fe nanocubes and {111} facet-enclosed Pt3Fe nanorods. They also show good stability with negligible activity change after five cycles. Density functional theory calculations reveal that, with high-indexed facet engineering, the Fe-3d band is an efficient d-d coupling correlation center for boosting the Pt 5d-electronic exchange and transfer activities towards the NRR. 相似文献
5.
E.W. Tschudi 《Journal of The Franklin Institute》1927,204(2):219-225
A cold cathode discharge tube has an auxiliary tube attached from which cathode-rays are projected against the main cathode. A photo-electric cell, attached to a monochromatic illuminator, is used to measure relative intensity distribution of Hγ and Hδ respectively, from the main cathode through the cathode dark space into the negative glow with and without excitation of the auxiliary tube. When the main cathode is bombarded by the electron stream the intensity of spectral illumination in the negative glow is increased by about 20 per cent. This increase does not result from the mere addition of an illumination, which appears when the auxiliary tube is alone excited, to the illumination of the main discharge, but may be attributed to the production of soft X-rays in the gas which are capable of exciting the gas molecules.R. Seeliger and co-workers have investigated spectrophotometrically the several characteristic sections of a cold cathode discharge tube. Their method consisted of an examination, with a microphotometer, of spectrograms taken at points along the discharge. The intensity distribution of any spectral line was found continuous in passing from one portion of the discharge to another, e.g., from the Faraday dark space into the positive column, and that the maxima of illumination for different lines appeared displaced relative to one another.A. Wehnelt and A. Jachan demonstrated with several experimental arrangements the effect of bombarding the cold cathode of an ordinary discharge tube with a beam of cathode-rays. There resulted an increase in the total intensity of illumination in the tube together with a shrinkage of the cathode dark space.The purpose of the present investigation was to examine the effect such an electronic bombardment would produce upon the spectral intensity distribution near the cathode of a hydrogen discharge in Hγ and Hδ alone were capable of investigation. 相似文献
6.
Gottweis H 《Social studies of science》1995,25(2):195-235
Policy-making, as exemplified by biotechnology policy, can be understood as an attempt to manage a field of discursivity, to construct regularity in a dispersed multitude of combinable elements. Following this perspective of politics as a textual process, the paper interprets the politicization of genetic engineering in Germany as a defence of the political as a regime of heterogeneity, as a field of 'dissensus' rather than 'consensus', and a rejection of the idea that the framing of technological transformation is an autonomous process. From its beginning in the early 1970s, genetic engineering was symbolically entrenched as a key technology of the future, and as an integral element of the German politics of modernization. Attempts by new social movements and the Green Party to displace the egalitarian imaginary of democratic discourse into the politics of genetic engineering were construed by the political élites as an attack on the political order of post-World War II Germany. The 1990 Genetic Engineering Law attempted a closure of this controversy. But it is precisely the homogenizing idiom of this 'settlement' which continues to nourish the social movements and their radical challenge to the definitions and codings of the politics of genetic engineering. 相似文献
7.
Piotr Tarka 《Information processing & management》2019,56(3):541-553
The main purpose of this paper is to investigate the relationships between three theoretical constructs developed in the course of the study measuring: (a) managers' memory capacity, (b) information processing, as a part of general system of cognitive capabilities, and (c) their perception of market research usefulness. In particular, we diagnose managers' natural limitations associated with cognition which determine their capabilities to deal with the market research information storage and retrieval as well as research information processing. With this intention and theoretical assumption, we designed and implemented a two-phase process of research. In the first phase, based on the literature review; face-to-face in-depth interviews and a pilot study (a pretest) we developed measurement models for the proposed theoretical constructs. Next, we conducted quantitative research among 213 highly experienced managers working in multinational companies in a European country (Poland), where the sample included individuals who were responsible for planning strategic and tactical marketing activities. Based on the structural equation modeling as the analytical strategy, the empirical research results revealed that managers in business organizations due to limited cognitive capabilities such as lower-than-average memory capacity and poor information processing, develop wrong perceptions of the usefulness of market research. Managers, when faced with difficulties regarding information storage and retrieval, as well as information processing, react negatively towards that research. Finally, we explained the reasons as to why managers in companies perceive market research in a negative light, as well as presented the most important theoretical and managerial implications. 相似文献
8.
专利产业化基地是促进我国自主知识产权转化的新型服务平台，其构建和运作模式尚处于探索阶段。现作为试点的实体基地在运作过程中出现组织构架上的诸多问题，据此引入虚拟化的概念，并对此新模式在我国推行的可行性进行了分析研究，并以重庆为例设计具体运作方案。 相似文献
9.
Bjørn K. Myskja 《Ethics and Information Technology》2008,10(4):213-220
Trust can be understood as a precondition for a well-functioning society or as a way to handle complexities of living in a
risk society, but also as a fundamental aspect of human morality. Interactions on the Internet pose some new challenges to
issues of trust, especially connected to disembodiedness. Mistrust may be an important obstacle to Internet use, which is
problematic as the Internet becomes a significant arena for political, social and commercial activities necessary for full
participation in a liberal democracy. The Categorical Imperative lifts up trust as a fundamental component of human ethical virtues – first of all, because deception and coercion, the antitheses of trust,
cannot be universalized. Mistrust is, according to Kant, a natural component of human nature, as we are social beings dependent
on recognition by others but also prone to deceiving others. Only in true friendships can this tendency be overcome and give
room for unconditional trust. Still we can argue that Kant must hold that trustworthy behaviour as well as trust in others
is obligatory, as expressions of respect for humanity. The Kantian approach integrates political and ethical aspects of trust, showing that protecting the external
activities of citizens is required in order to act morally. This means that security measures, combined with specific regulations
are important preconditions for building online trust, providing an environment enabling people to act morally and for trust-based
relationships. 相似文献
10.
Knight DM 《Endeavour》2000,24(4):165-169
Humphry Davy (1778–1829) was one of the first professional scientists, earning his living and rising spectacularly from an impoverished upbringing in Cornwall to be President of the Royal Society and a baronet. He owed his rise to patronage as well as to his range of abilities: as a lecturer, as a chemical theorist and as a very early applied scientist. But his exalted position brought him little happiness, for he could not satisfy all the hopes put upon him as the successor to Sir Joseph Banks. Admired rather than loved, he became unpopular and was seen as haughty. In his last two years, spent wandering lonely and sickly in Italy and the Alps, he sought to make sense of his life, writing dialogues as his bequest to the new generation. 相似文献
11.
At the university, each institute or chair can be seen as a small independent enterprise in respect of education and research. For this reason, the efficiency of management as well as the improvement of education and research within this unit is more and more at a premium. The students need a good working environment and the opportunity to gain and share information in order to carry out successful research and course work. This paper shows how education at a university semiconductor laboratory can be improved by using a content management system to build a knowledge management system. The structuring and implementation will be shown as well as students’ rating of it. The results support the conclusion that the knowledge base is a great step forward for improving education and research in a complex environment. 相似文献
12.
microRNAs (miRNAs) are evolutionarily conserved small noncoding RNAs, also known as micromanagers of gene expression. Polymorphisms
in the miRNA pathway (miR-polymorphisms) are emerging as powerful tools to study the biology of a disease and have the potential
to be used in disease prognosis and diagnosis. Advancements in the miRNA field also indicate a clear involvement of deregulated
miRNA gene signatures in cancers, and several polymorphisms in pre-miRNA, miRNA binding sites or targets have been found to
be associated with various cancers. The miRNA polymorphisms have also been reported to influence tumor aggressiveness as well
as survival of cancer patients. miRNAs have a revolutionary impact on cancer research over recent years. They emerge as important
players in tumorigenesis, leading to a paradigm shift in oncology. The extensive and comprehensive use of miRNA microarrays
has enabled the identification of a number of miRNAs as potential biomarkers for cancer. Many miRNAs have been identified
to act as oncogenes, tumor suppressors, or even modulators of cancer stem cells and metastasis. Some studies not only reported
the identified miRNA biomarkers, but also deciphered their target genes and the underlying mechanisms. The rapid discovery
of many miRNA targets and their relevant pathways has contributed to the development of miRNA-based therapeutics. 相似文献
13.
Reinhold Tacke Dipl.-Chem. Dr. rer. nat. habil. Harald Zilch Dipl.-Chem. Dr. rer. nat. 《Endeavour》1986,10(4)
Sila-substitution (C/Si-exchange) of drugs is one of the approaches currently used in the search for new biologically active organosilicon compounds. Replacement of specific carbon atoms in drugs by silicon results in changes in chemical and physicochemical properties as well as in the structure. As a consequence, the biological properties, such as pharmacological potency and selectivity and toxicity, may be influenced. Systematic sila-substitution seems to be a useful and efficient strategy in drug design and should be regarded as a complementary tool for the development of new drugs. 相似文献
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《Information processing & management》2023,60(3):103248
In a dynamic retrieval system, documents must be ingested as they arrive, and be immediately findable by queries. Our purpose in this paper is to describe an index structure and processing regime that accommodates that requirement for immediate access, seeking to make the ingestion process as streamlined as possible, while at the same time seeking to make the growing index as small as possible, and seeking to make term-based querying via the index as efficient as possible. We describe a new compression operation and a novel approach to extensible lists which together facilitate that triple goal. In particular, the structure we describe provides incremental document-level indexing using as little as two bytes per posting and only a small amount more for word-level indexing; provides fast document insertion; supports immediate and continuous queryability; provides support for fast conjunctive queries and similarity score-based ranked queries; and facilitates fast conversion of the dynamic index to a “normal” static compressed inverted index structure. Measurement of our new mechanism confirms that in-memory dynamic document-level indexes for collections into the gigabyte range can be constructed at a rate of two gigabytes/minute using a typical server architecture, that multi-term conjunctive Boolean queries can be resolved in just a few milliseconds each on average even while new documents are being concurrently ingested, and that the net memory space required for all of the required data structures amounts to an average of as little as two bytes per stored posting, less than half the space required by the best previous mechanism. 相似文献
16.
No project is an island: linking projects to history and context 总被引：2，自引：0，他引：2
Mats Engwall 《Research Policy》2003,32(5):789-808
Theories on project management are dominated by a perspective on singular projects, treating the unit of analysis as a lonely phenomenon. Anchored in a comparative case study, this paper discusses how the interior processes of a project are influenced by its historical and organizational context. The paper illustrates how the structures and procedures employed in a project have to be understood in relation to previous and simultaneous courses of activity, to future plans, and to standard operating procedures, traditions, and the norms of its surroundings. The findings suggest that future research on project management needs to extend its temporal scope, analyzing how project practices evolve through history over prior, present, and future projects, as well as its organizational scope, analyzing how project practices relate to long-term institutions as well as simultaneous activities in its environment. 相似文献
17.
Context is hot in information science as well as in numerous other disciplines, but what exactly does this mean in and for research? The paper discusses the differences between objectified and interpretative approaches to context. It is argued that in information needs and seeking research (INS), the former approach has thus far been more common. Contextual entities are usually described to provide a background for the study of individuals' or groups' information behavior, not in order to point out how contextual knowledge is. From a metatheoretical viewpoint, context is the site where a phenomenon is constituted as a research object. One way of understanding INS phenomena is to define them as patterns of behavior; another way is to understand them as phenomena mediated by social and cultural meanings and values. A large proportion of current theory and research in INS studies is located within the behaviorist framework which has become so familiar and taken-for-granted that it is rarely seen as a paradigm. 相似文献
18.
Existing structures should be exploited as best as possible in the course of document reuse. Reuse may take multiple forms: rearranging a single document so as to provide different views of the same information, copying a portion of a single document so as to provide a portion of a new document, and combining portions of existing documents to constitute a new document. We present algorithms for doing this reuse, describe some computer tools which we have built to support this reuse, and provide real examples. For significant reuse, the information in existing documents needs to be abstracted so as to highlight the conceptual patterns. Outlines are a structure which could, at least, partially support this function. 相似文献
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