• 한국자기공명학회논문지
• /
• 제19권1호
• /
• pp.29-35
• /
• 2015

The microscopic dynamics of $CsH_2PO_4$, with two distinct hydrogen bond lengths, are studied by static nuclear magnetic resonance (NMR) and magic angle spinning (MAS) NMR. The proton dynamics of the two crystallographically inequivalent hydrogen sites were discussed in terms of the $^1H$ NMR and $^1H$ MAS NMR spectra. Although the hydrogen bonds have two inequivalent sites, H(1) and H(2), distinct proton dynamics for the two sites were not found. Further, the $^{133}Cs$ spectrum is more or less continuous near $T_{C1}$ (=153 K). Finally, the phase transition mechanism of $T_{C1}$ in $CsH_2PO_4$ is related to the ordering of protons.

• Composites Research
• /
• 제35권1호
• /
• pp.23-30
• /
• 2022

폴리카보실란은 탄화규소 섬유 방사와 세라믹 제조를 위해 필요한 중요한 전구체이며, 이 전구체는 제조방법 및 공정에 따라 고내열성 및 내산화성 및 연속적인 탄화규소 섬유 생산 능력이 달라진다. 탄화규소 섬유는 폴리카보실란의 합성, 정제 및 분자구조제어기술, 그리고 이를 이용한 용융방사 및 안정화, 열처리 공정을 통해 제조된다. 본 논문에서는 폴리카보실란 전구체를 다양한 용매처리를 통하여 전구체 내에 존재하는 미반응물 및 저분자량의 정제효과를 파악하였으며, 또한 다양한 온도에서의 열처리에 따른 폴리카보실란 전구체의 중합 및 네트워크 재배열에 의한 변화에 대해 열적 분석을 실시하였다. 특히, 폴리카보실란 전구체의 유변물성 특성을 통해 용매처리 및 열처리에 따른 복합점도 및 구조적 배열의 변화를 분석하였다.

• 공업화학
• /
• 제17권3호
• /
• pp.331-334
• /
• 2006

본 연구에서는 포집부의 재질과 포집장치를 개선하여 배향성이 존재하는 극세섬유를 제조하였다. 방사용액은 polyamide-polyimide copolymer (PAI)를 사용하였다. 포집부의 재질을 변화하고 동일한 전압을 가하여 제조된 극세섬유의 형태를 비교하였다. 한편, 물 포집부와 회수장치로 구성된 장치를 통하여 극세섬유를 제조하고 SEM을 통하여 관찰하였다. 실험결과, 동일한 전압으로 제조된 섬유의 평균직경은 포집부의 재질과 회수방식에 영향을 받지 않았으나 포집부의 재질과 회수방법에 따라 섬유의 형태가 변화하는 것이 관찰되었다. 포집부에 누적시켜 제조된 극세섬유는 배향성이 존재하지 않는 그물형 구조인데 반하여, 별도의 회수장치를 통하여 연속적으로 회수된 극세섬유는 배향성이 존재함을 확인하였다. 이는 물 포집부가 섬유의 유도, 임시집적, 섬유와의 마찰 그리고 이동경로 역할을 하였고, 회수장치는 속도 조절을 통하여 물과 섬유간의 마찰을 제어함으로써 연속적인 회수가 가능한 것으로 판단된다.

• 한국염색가공학회지
• /
• 제17권4호
• /
• pp.7-14
• /
• 2005

The purpose of this study was to develop the color matching program with the excellent camouflage capacity in the near infrared range($\~$1100nm) including the visible light range for cotton fabrics. It was measured IR spectral reflectance in the range of $380\~1,100nm$ after dyed with vat dyes, and we made database for reflectance with various concentration on vat dyes which have a low reflectance value in the infrared range. The color matching algorithm that could be simulated in both the human visible light and the near infrared range was constructed by numerical analysis method using the database. In this study we also developed the dyeing conditions and dyeing process through the continuous-dyeing experiment with the vat dyes for cotton fabrics.

• Composites Research
• /
• 제26권3호
• /
• pp.160-164
• /
• 2013

In this study, the effect of phosphoric acid (PA) as a fiber spinning aid on the strength increase of polyacrylonitrile (PAN) nano-fibers by using modified mechano-electrospinning technologies has been analyzed. The medium carbonization temperature of $800^{\circ}C$ has been selected for the future economic production of these new materials. The concentration of PAN in dimethyl sulfoxide (DMSO) was fixed as 5 wt%. The weight fraction of PA was selected as being 2%, 4%, 6%, and 8% in comparison to PAN. These solutions have been used to make the nanofibers. The mechano-electrospinning apparatus installed in KRICT was made by our own design. By using this apparatus the continous and highly aligned precursor nano-fibers have been obtained. The bundle of 50 well aligned nano diameter continuous fibers with the diametr of 10 microns with 6 wt% phosphoric acid for addition showed maximum mechanical properties of 1.6 GPa as tensile strength and 300 GPa as Young's modulus. The weight of final product can be increased 19%, which can improve the economical benefits for the application of these new materials.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 춘계학술대회
• /
• pp.31-35
• /
• 2004

The speed competition of optical disk drive has been accelerated with the fast advancement of its storage density and data transmission technology. The continuous increase of the spinning speed of CD meets the unexpected and catastrophic failure of disk during the operation. The effect of its thickness and outer radius of disk were investigated to reduce stresses and J-integral around the crack tip. The effect of its thickness was considered ahead of the crack tip. In the effect of outer radius of disk, linear elastic fracture mechanics was used to obtain the critical crack length, which indicates the onset length for unstable crack growth. This approach is so significant as to detect the growing crack by disk drive before the catastrophic failure, which will provide the standard size of its safety for high-speed disk drive.

• 한국표면공학회지
• /
• 제56권5호
• /
• pp.309-319
• /
• 2023

Non-woven fabric is a textile product made by spinning thermoplastic polymers without manufacturing processes such as stretching, doubling, twisting, weaving, and knitting to form a sheet-shaped web in which fibers are tangled with each other, and then combining them by mechanical and physical methods. In addition, the non-woven fabric manufacturing process has various raw material choices, high productivity, so it is a textile manufacturing technology that can have various uses and increase added value. This study was conducted to control the shape and physical properties of products by improving the manufacturing method of melt-blown non-woven fabrics using process technology that easily changes the shape of non-woven fabrics and improves mechanical properties. In particular, it is considered that a non-woven fabric with a thin material shape and improved mechanical properties will be easily applied to a continuous secondary battery manufacturing industry such as roll to roll operation.

• 대한간호학회지
• /
• 제36권1호
• /
• pp.103-113
• /
• 2006

Introduction: It is important to understand the nature of the identity through the live experiences of Home Care Nurse Practitioner(HCNP) because the role identity of a professional is constructed by continuous social interactions, This study aims to understand the construction of the role identity of HCNP. Method: Data was collected from 12 hospital based HCNPs. This study involved two focus group discussion sand four in-depth individual interviews. The main question was 'what is the role of HCNP?' The debriefing notes and field notes were analyzed using consistent comparative data analysis method. Result: First, Home care (He) is a small clinic. HCNP brings it to home to provide various services. Second, HC is the real nursing and HCNP is the 'genuine' nurse who actualizes the essence of nursing in practice. Third, HC is empowering activity to promote self-care ability of the patients and their caregivers. Forth, HC is like the dish-spinning required high-level mastery and HCNP is an expert who provides the most appropriate services to the patients. Conclusion: HCNPs have the role identity as a highly qualified professional who delivers services from hospital to home, actualizes the essence of nursing in practice, empowers the patients and their caregivers to have self-efficacy to recover, and offers the most appropriate nursing care.

• 폴리머
• /
• 제25권6호
• /
• pp.765-773
• /
• 2001

본 연구에서는 수중의 $Co^{2+}$, $Ni^{2+}$ , $Cr_2O_7\;^{2-}$등의 유해이온을 선택적으로 흡착 제거시키기 위하여 단량체의 몰비를 달리하여 AN-co-(MMA/IA)를 합성하고, 습식방사에 의해 제조한 PAN 섬유를 산가수분해하여 PAN계 다관능성 이온교환섬유를 합성하였다. 또한 합성한 이온교환섬유의 구조, 관능화도, 이온교환용량, 분포계수. 기계적 물성 등을 시험하였다. 이온교환체의 음이온교환 용량은 IA의 mole 함량이 증가함에 따라 4.5~4.2 meq/g으로 감소하고, 양이온교환용량은 1.8-2.2 meq/g으로 증가하는 경향을 보였다. 인장감도는 공중합체 내에 IA의 함량이 0.008 mol%까지 증가하여 216 $kg/cm^2$로 최대값을 나타냈고, AN-co-(MMA/IA) 이온교환체의 분포계수 측정 결과 Co(II)와 Ni(II)는 pH 5-6영역에서 최대를 보였고, Cr(III)는 pH 3-4에서 최대값을 나타냈다. 또한 다성분 계상에서의 연속식 흡착 실험에서 Cr(III > Co(II) > Ni(II)의 순으로 선택능을 나타냈다.

• Human Ecology Research
• /
• 제56권4호
• /
• pp.407-416
• /
• 2018

This study investigated the characteristics and changes of Jeongbang-village silk culture Jeollanam-do Province during Japanese Colonial Rule with a focus in on Gokseong-gun & Damyang-gun Jeongbang-village. The results of the study are as follows. First, after Japanese occupation, it changed from a traditional silkworm species, the Joseon Silkworms and the mulberry tree to an improved Japanese species. Japan established a silk spinning mill called Jongyeon Textile factory in Gwangju and Jeongbang Village was formed in poor rural areas. Second, the way of village management consisted of buying a large number of land for mulberry plans and creating mulberry fields as a cheap way to utilize the labor force for women and men in rural areas. Third, since the end of the Japanese colonial era, mulberry fields in Jeongbang villages which the Japanese left, were sold at a cheap price to Koreans. After the Korean War, the Korean government's efforts to modernize the silkworm industry resulted in a continuous plan to increase the number of silkworms. The impact of government policies has also increased the production of silkworms in these areas. However, since the early 1980s, Korean companies have been affected by Japanese economic policies and dumping by China that has resulted in in a sharp decline in their production. In the case of Gokseong-gun and Damyang, the production of silk products was halted and switched to other crops in the early 1990s when the farming industry began to decline.