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741.

중학교 내적 과정변인의 인과관계를 통한 학교효과 분석

곽수란 한국교육학회 교육학연구 29 Pages

한국교육학회 교육학연구 2007, 45권 2호 1 1-29 (29 pages)

곽수란 저
...
- 5,800원
이 연구는 한국교육종단연구(Korean Education Longitudinal Study)’ 데이터를 사용하여 중학교 학교효과를 탐색하고 있다. 특히 학교 내적 과정변인을 통해 학교 효율성을 탐색하는 ‘효과적인 학교’ 연구 틀을 사용하여 학업성취 상위인 효과적인 학교와 하위인 비효과적인 학교를 선별하여 두 학교군의 내적 특성 간의 인과관계를 확인하였다. 연구대상은 학업성취가 상위인 22개교와 하위인 22개교 학생 2,147명과 교사 865명이며, 분석모형은 5개의 잠재변인(교장지도성, 교사과정변인, 학생과정변인, 인지적 성취, 정의적 성취)과...
742.

Graphitization of PAN-based carbon fibers by CO₂ laser irradiation

Liangbo Yao, Weimin Yang, Sanyang Li, Yang Sha, Jing Tan, Ying An, Haoyi Li 한국탄소학회 Carbon Letters 6 Pages

한국탄소학회 Carbon Letters 2017, Vol.24 13 97-102 (6 pages)

Liangbo Yao, Weimin Yang, Sanyang Li, Yang Sha, Jing Tan, Ying An, Haoyi Li 저
...
- 3,000원
Graphite fibers are materials with a high specific modulus that have attracted much interest in the aerospace industry, but their high manufacturing cost and low yield are still problems that prevent their wide applications in practice. This paper presents a laser-based process for graphitization of carbon fiber (CF) and explores the effect of laser radiation on the microstructure of CF. The obtained Raman spectra indicate that the outer surface of CF evolves from turbostratic structures into a...
743.

Optical sensitivity of DNA-dispersed single-walled carbon nanotubes within cement composites under mechanical load

Jin Hee Kim, Inkyu Rhee, Yong Chae Jung, Sumin Ha, Yoong Ahm Kim 한국탄소학회 Carbon Letters 7 Pages

한국탄소학회 Carbon Letters 2017, Vol.24 12 90-96 (7 pages)

Jin Hee Kim, Inkyu Rhee, Yong Chae Jung, Sumin Ha, Yoong Ahm Kim 저
...
- 3,000원
We demonstrated the sensitivity of optically active single-walled carbon nanotubes (SWCNTs) with a diameter below 1 nm that were homogeneously dispersed in cement composites under a mechanical load. Deoxyribonucleic acid (DNA) was selected as the dispersing agent to achieve a homogeneous dispersion of SWCNTs in an aqueous solution, and the dispersion state of the SWCNTs were characterized using various optical tools. It was found that the addition of a large amount of DNA prohibited the...
744.

Hole quality assessment of drilled CFRP and CFRP-Ti stacks holes using polycrystalline diamond (PCD) tools

Dave Kim, Aaron Beal, Kiweon Kang, Sang-Young Kim 한국탄소학회 Carbon Letters 8 Pages

한국탄소학회 Carbon Letters 2017, Vol.23 1 1-8 (8 pages)

Dave Kim, Aaron Beal, Kiweon Kang, Sang-Young Kim 저
...
- 3,000원
Polycrystalline diamond (PCD) tools possessing high hardness and abrasive wear resistance are particularly suited for drilling of carbon fiber reinforced plastic (CFRP) composites, where tool life and consistent hole quality are important. While PCD presents superior performance when drilling CFRP, it is unclear how it performs when drilling multi-stack materials such as CFRP-titanium (Ti) stacks. This comparative study aims to investigate drilling of a Ti plate stacked on a CFRP panel when...
745.

The impact fracture behaviors of CFRP/EVA composites by drop-weight impact test

Sun-Ho Go, Hong-Gun Kim, Hee-Jae Shin, Min-Sang Lee, Hyun-Gyung Yoon, Lee-Ku Kwac 한국탄소학회 Carbon Letters 10 Pages

한국탄소학회 Carbon Letters 2017, Vol.21 4 23-32 (10 pages)

Sun-Ho Go, Hong-Gun Kim, Hee-Jae Shin, Min-Sang Lee, Hyun-Gyung Yoon, Lee-Ku Kwac 저
...
- 3,000원
absorbance is dispersed by the fibers, it was more likely for the brittle failure mode to occur. In the cases of Type 3 through Type 5, in which the role of the EVA sheet is more prominent because it absorbs the impact energy rather than dispersing it, a clear form of puncture failure mode was observed. Based on the above results, it was found that all the observation values decreased as the EVA lamination increased compared with the CFRP lamination. The EVA lamination was thus found to have a...
746.

Effects of coal tar pitch addition on the wear behavior of carbon/carbon composites

Young Chan Jung, Duk Soo Kang, Kyong Yop Rhee, Soo Jin Park, David Hui 한국탄소학회 Carbon Letters 4 Pages

한국탄소학회 Carbon Letters 2016, Vol.20 9 62-65 (4 pages)

Young Chan Jung, Duk Soo Kang, Kyong Yop Rhee, Soo Jin Park, David Hui 저
...
- 1,500원
number of studies have been conducted on the performance of C/C composites brake [6-9]. Generally, C/C composites are produced by the carbonization of the matrix precursors of carbon composites. However, some defects, such as porosity and micro-cracks, are also induced during carbonization, and these defects degrde the mechanical properties. Therefore, various methods have been adopted to reduce the development of defects during the manufacture of C/C composites [10-14]. On the other hand, coal...
747.

Mechanisms of Na adsorption on graphene and graphene oxide: density functional theory approach

Hye Sook Moon, Ji Hye Lee, Soonchul Kwon, Il Tae Kim, Seung Geol Lee 한국탄소학회 Carbon Letters 5 Pages

한국탄소학회 Carbon Letters 2015, Vol.16 No.2 7 116-120 (5 pages)

Hye Sook Moon, Ji Hye Lee, Soonchul Kwon, Il Tae Kim, Seung Geol Lee 저
...
- 1,500원
We investigated the adsorption of Na on graphene and graphene oxide, which are used as anode materials in sodium ion batteries, using density functional theory. The adsorption energy for Na on graphene was -0.507 eV at the hollow sites, implying that adsorption was favorable. In the case of graphene oxide, Na atoms were separately adsorbed on the epoxide and hydroxyl functional groups. The adsorption of Na on graphene oxide-epoxide (adsorption energy of -1.024 eV) was found to be stronger than...
748.

Preparation and characterization of carbon fiber-reinforced thermosetting composites: a review

Fan-Long Jin, Soo-Jin Park 한국탄소학회 Carbon Letters 11 Pages

한국탄소학회 Carbon Letters 2015, Vol.16 No.2 1 67-77 (11 pages)

Fan-Long Jin, Soo-Jin Park 저
...
- 4,000원
Carbon fibers (CFs) have a unique combination of properties which allow them to be widely used as reinforcing materials in advanced polymer composites. The mechanical properties of CF-reinforced polymer composites are governed mainly by the quality of interfacial adhesion between the CFs and the polymer matrix. Surface treatments of CFs are generally carried out to introduce chemical functional groups on the fiber surfaces, which provide the ability to control the surface characteristics of CFs....
749.

Influence of hot-pressing pressure on the densification of short-carbon-fiber-reinforced, randomly oriented carbon/carbon composite

Thakur Sudesh Kumar Raunija and Sharad Chandra Sharma 한국탄소학회 Carbon Letters 9 Pages

한국탄소학회 Carbon Letters 2015, Vol.16 No.1 4 25-33 (9 pages)

Thakur Sudesh Kumar Raunija and Sharad Chandra Sharma 저
...
- 3,000원
The prime objective of this research was to study the influence of hot-pressing pressure and matrix-to-reinforcement ratio on the densification of short-carbon-fiber-reinforced, randomly oriented carbon/carbon-composite. Secondary objectives included determination of the physical and mechanical properties of the resulting composite. The ‘hybrid carbon-fiberreinforced mesophase-pitch-derived carbon-matrix’ composite was fabricated by hot pressing. During hot pressing, pressure was varied from 5...
750.

Method and mechanism of dispersing agent free dispersion of short carbon fibers in silicon carbide powder

Thakur Sudesh Kumar Raunija, Mariamma Mathew, Sharad Chandra Sharma 한국탄소학회 Carbon Letters 7 Pages

한국탄소학회 Carbon Letters 2014, Vol.15 No.3 4 180-186 (7 pages)

Thakur Sudesh Kumar Raunija, Mariamma Mathew, Sharad Chandra Sharma 저
...
- 3,000원
This study highlights a novel method and mechanism for the rapid and effective milling of carbon fibers (CFs) in silicon carbide (SiC) powder, and also the dispersion of CFs in SiC powder. The composite powders were prepared by chopping and exfoliation of CFs, and ball milling of CFs and SiC powder in isopropyl alcohol. A wide range of CFs loading, from 10 to 50 vol%, was studied. The milling of CFs and SiC powder was checked by measuring the average particle size of the composite powders. The...

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