1,720,953 research outputs found
Fundamental Studies on the PU-NC Semi-IPNs Wooden Coatings
No full text本研究以屬於天然再生資源之吹製型篦麻油(BCO)為基質之二液型聚胺基
甲酸酯(PU)，與由天然纖維素硝化製成且仍能保留木材質感之硝化纖維
素(NC)，兩者合成半互穿聚合體網狀結構物(Semi-IPNs)，期望藉此提升
PU與NC所無法達到的性能，進而探討其應用於木器塗料之可行性，結果發
現以芳香族聚異氰酸鹽(PTDI)為硬化劑之PU與1/2〞NC可以簡易而成功地
製備PU-NC semi-IPNs，在各種NCO/OH莫耳比及不同PU/NC重量比之配方條
件，PU與NC均具相容性，且均可以明顯縮短PU的乾燥時間，而且膠化時間
達30日以上，可以解決PU乾燥速度緩慢及有可使用時間限制的缺點，其中
又?In this study , the semi-interpenetrating polymer networks
(semi-IPNs) which were made from blown castor oil (BCO) based
polyurethane (PU) and nitrocellulose (NC) were prepared for
wooden coatings. The effects of several factors such as the NCO/
OH molar ratios , PU/NC composition , addition sequence of
components , amount of PU catalyst , kinds of NC and
polyisocyanate on properties of coatings and films were
investigated. Some experiments concerning the viscosity , gel
time , drying time of coatings and me
The semi-IPNs were prepared from PU containing aromatic
polyisocyanate (PTDI) and 1/2〞NC under different NCO/OH molar
ratios of PU and PU/NC compositions. It revealed that PU and NC
were compatible on all of conditions and the drying time of PU
could be shortened significantly and had no limitations of pot-
life by interpenetrating with NC. The formulation of semi-IPNs
with NCO/OH=1.2 , PU/NC=70/30 (R1.2-70)had a best compatible
system and was an ideal interpenetration between PU and NC and
excellent p
For the PU-NC semi-IPNs under NCO/OH=1.2 , the degree of
interpenetration between PU and NC , properties of films of
NCaBCOaPTDI addition sequence were better than those of the
BCOaPTDIaNC sequence . Compared R1.2-70 PU-NC semi-IPNs with
four kinds of polyisocyanates (PTDI , PMDI , PIPDI , PHDI)
respectively , which containing PMDI had the highest viscosity
and containing both PTDI and PMDI had the shortest drying time
of coatings. Except the semi-IPNs containing PMDI would gel
within 12 hours , the gel
Compared the R1.2-70 PU-NC semi-IPNs with three kinds of
NC(1/2〞,1/4〞1/16〞) respectively ,which containing 1/2〞NC
had the shortest drying time of coating and had the best
tensile strength , elongation at break , lightfastness and
solvent resistance of films , while , containing 1/16〞NC had
the lowest viscosity of coating , the best thermal stability
and the highest quantity of thermal expansion of film. In
addition , the gel time for all of the semi-IPNs could reach
above 30 days. Dynamic mechanic
By adding the PU catalyst DBTDL to the PU-NC semi-IPNs ,
the pot-life of coatings would be limited but could shorten the
drying time of coatings and enhanced the tensile strength ,
elongation at break , lightfastness and solvent resistance of
films with alphatic polyisocyanates . It would improve the
thermal stability of films with aromatic polyisocyanates but
the lightfastness and gloss retention were inferior to those of
semi-IPNs without DBTDL. It could shorten the drying time of
coatings and enhance封面
目錄
圖目次
表目次
摘要
SUMMARY
一、前言
二、文廚回顧
（一）IPNs之原理
（二）IPNs之製備
（三）IPNs之歷史與應用
三、材料與方法
（一）試驗材料
（二）試驗方法
1.材料性質之測定
(1)篦麻油酸價之測定
(2)篦麻油羥價之測定
(3)聚異氰酸鹽NCO基之定量
2.PU之調配
3.PU-NC semi-IPNs之合成
(1)不同NCO/OH莫耳比與PU/NC組成之Semi-IPNs
(2)組成分添加次序不同之Semi-IPNs
(3)潻加PU催化劑之Semi-IPNs
(4)不同聚異氰酸鹽之Semi-IPNs
(5)不同NC之Semi-IPNs
4.試材之塗裝
5.塗料性質之測定
(1)粘度
(2)乾燥時間
(3)膠化時間
6.塗膜性質之測定
(1)機械性質
附著性
拉伸強度
硬度
(2)耐光性
(3)冷熱循環試驗
(4)熱機械分析
(5)熱重量分析
(6)耐溶劑性
(7)動態機械分析
(8)傅立葉紅外線光譜分析
(9)掃描式電子顯微鏡觀察
四、結果與討論
（一）NCO/OH莫耳比與PU/NC組成對Semi-IPNs性質之影響
（二）組成分添加次序對Semi-IPNs性質之影響
（三）添加PU催化劑對Semi-IPNs性質之影響
1.添加DBTDL對PU性質之影響
2.添加DBTDL對semi-IPNs性質之影響
（四）聚異氰酸鹽種類對Semi-IPNs性質之影響
1.不同聚異氰酸鹽之semi-IPNs
2.不同PU/NC重量比之semi-IPNs
（五）硝化纖維素種類對Semi-IPNs性質之影響
五、結論
六、參考文
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
- …
