1,720,961 research outputs found
Ｂ介子弱蛻變為二擬純量介子的Ｓｕ（４）振幅之計算
No full text[[abstract]]計算B 介子弱蛻變的Su（4 ）振幅，並比較其間之相關性，並限定Cabbibo 角度的範
圍。Kobayashi-Maskawa 的六夸克模型分析哈密頓算符群的結構，並以求Su（4 ）C-
G 係數的方法計算B 介子弱蛻變為二擬純量介子的Su（4 ）振幅。
B介子蛻變成向量介子和擬純量介子之研究
No full text[[abstract]]粒子間的交互作用一強交互作用，弱交互作用和電磁交互作用一經常是同時出現。而
弱作用是一強度甚小的作用，它每每被強作用和電磁作用掩蓋住，而味道發生改變的
蛻變，是弱作用獨有的性質，T（４S）經由BB再弱蛻變為其它不含ｂ夸克介子（moson
）的現象，提供了個甚佳研究弱作用本質的空間。
本文根據Weinberg-Salam所提電弱統一理論和Kobayashi-Maskawa 所提交個夸克的建
議，以對稱群的方法法計算Ｂ介子弱蛻變為一個擬純量介子（pseudoscalar meson）
和一個向量介子（vector meson）的各種不同末狀態的SU（４）之振幅）。
下介子之非輕子弱蛻變
No full text[[abstract]]一九七七年發現了三個寬度甚窄的共振態γ, γ 和γ , 它們是由下夸克(botom g
uark) 和反夸克構成的爾縛態, 一九七九年又發現了第四個共振態γ , 而其寬度遠
大於前三個γ 狀態, 表示下介子和反下介子可由γ 蛻變而產生, 可供給我們研究
弱蛻變的基本性質。
本文以六個夸克的標準模型(Standard model)為基礎, 來研究終狀態為兩個擬純量(P
seu-dscalar)介子的下介子之蛻變, 我們利用群的對稱性計算不同蛻變過程的SU(3)
振幅, 進而找出振幅音簡單的關係式, 這些關係式可用來和實驗比較, 以驗證弱作用
的基本性質。
SO(10)李代數及大統一模型之探討
No full text[[abstract]]本文主要由鄧金的方法研究大統一模型SO(10)的李代數，表示論，及其子群，並
且探討SO(10)對稱破壞至標準模型的可能路徑，然後利用重整化群方程式和LEP 的
數據解出SO(10)兩步驟對稱破壞的大統一能標及中間能標的值，進而討論微中子質
量問題。為了幫助我們的研究，我們寫了一些程式，可提供不同SO(10)表象的特性
及SO(10)各種表象的量子數，以供有興趣者參考。
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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