• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.87-92
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• 2013

This paper focuses on analyzing the effects of primary user (PU) signal arrival on the local spectrum sensing performance. The probability for signal arrival at a sample in the sensing time is uniformly distributed in the sensing time. We first analyze the main factor that causes the degradation in the detection results in the conventional energy detection (CED) under the uniformly random arrival of the PU-signal. Thus we propose an approach in order to enhance the detection performance, in which an estimator which detects the arrival of the PU signal cooperates with a composite energy detection. The mathematical analysis and numerical simulation has validated the outperformance of the proposed approach compared to the CED.

• Journal of Biomedical Engineering Research
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• v.20 no.6
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• pp.547-553
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• 1999

생체재료로 사용되는 polyurethane(PU) 표면에 항혈전성 lumbrokinase(LK)를 고정함으로써 생체적합성을 향상시키고자하였다. 먼저 LK를 PU 표면에 고정하기 위한 가교제로서 4-azidoaniline hydrochloride와 poly(acrylic acid)를 이용하여 4-azidophenyl 작용기가 amido 결합으로 치환된 수용성, 광반응성 poly(acrylic acid)(PPa-II)를 합성하였다. H-nuclear magnetic reasonance spectrum(500MHz H-NMR)의 6-7 peak와 infrared spectrum (FT-IR) 의 2125.48 cm peak으로부터 PPA-II의 합성을 지원하였다. EH한 4-azidophenyl 작용기가 poly(acrylid acid) 잔기에 치환된 정도는 UV/VIS adpectrophotometric spectrum을 확인한 결과 11~14%임을 알 수있었다. 0.5 1및 5% PPA-II를 각각 광반응하여 얻은 PU는 39.5, 161.8 및 181.5 nmole/$\textrm{cm}^2$의 농도로 표면에 carvoxyl 작용기가 유도되었음을 알 수있었다. 0.05M KH2PO4 (pH 4.5) 용액에서 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide(EDC)를 촉매로 사용하여 LK를 PU표면에 amido 공유결합으로 고정하였으며, 이것은 지속적인 fibrinolytic 활성도를 보였다. PPA-II를 이용한 표면 개질 방법은 수용성 반응조건에서 이루어진다는 점과 광반응을 이용함으로써 특정부위에서의 표면개질이 가능하다는 점에서 그 응용가치가 크며 아울러 PU의 생체적합성을 향상시킬 수 있는 방법으로서 판단된다.

• Journal of Korean Medicine Rehabilitation
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• v.21 no.3
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• pp.71-78
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• 2011

Objectives : The purpose of this study is to report the combination effect of Chuna manipulation and warm needle acupuncture for a case of obstinate chronic tinnitus. Methods : We applied Danmuji Anchu Tracton technique, lateral pterygoid Chuna and warm needle acupuncture at SI19 once a day for 2 weeks. Visual analogue scale(VAS) was used for the intensity of tinnitus and tinnitus handicap inventory(THI) was evaluated. Results : VAS was improved from 6 to 2 in right ear, 4 to 1 in left ear after the treatment. THI was also improved from 54 to 34 after the treatmemt. Conclusions : The combined therapy of Chuna manipulation and warm needle acupuncture can be used for chronic tinnitus.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.81-85
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• 2003

PU block polymers are constituted by sequences of constitutional units CU which are : a diisocyanate T, a polyol or a polyamine V, an extensor E .Due to the CU different solubility parameters ,hard and soft micro domains are formed;they can aggregate into different phases. A linear PU can be described by two parameters R=T/N and $R_{E}$=(R-1)V/E.A stoichiometric model is proposed which gives the general formula of all the possible PU: X((TV)$_{k}$(TE)$_{n}$)$_{m}$X , where k and m can be calculated from the experimental molecular weights respectively of pre polymer and polymer and n= R-1.Physical properties depend on PU composition and on nature of CU. I.R. analysis is useful for discovering the hydrogen bonds location : DSC gives informations on the presence of the different phases .PALS analysis shows that nano cavities become tighter on increasing n. A series of particular Pus ,obtained from :TDI, a low molecular weight polyol, a cyclic extensor, at different R and RE was prepared and analysed. These PU are amorphous, monophasic and appear to be good candidates for membranes.nes.nes.

• Kyungpook Mathematical Journal
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• v.48 no.1
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• pp.15-24
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• 2008

Let $N{\geq}1$ and p > 1. Let ${\Omega}$ be a domain of $\mathbb{R}^N$. In this article we shall establish Kato's inequalities for quasilinear degenerate elliptic operators of the form $A_pu$ = divA(x,$\nabla$u) for $u{\in}K_p({\Omega})$, ), where $K_p({\Omega})$ is an admissible class and $A(x,\xi)\;:\;{\Omega}{\times}\mathbb{R}^N{\rightarrow}\mathbb{R}^N$ is a mapping satisfying some structural conditions. If p = 2 for example, then we have $K_2({\Omega})\;= \;\{u\;{\in}\;L_{loc}^1({\Omega})\;:\;\partial_ju,\;\partial_{j,k}^2u\;{\in}\;L_{loc}^1({\Omega})\;for\;j,k\;=\;1,2,{\cdots},N\}$. Then we shall prove that $A_p{\mid}u{\mid}\;\geq$ (sgn u) $A_pu$ and $A_pu^+\;\geq\;(sgn^+u)^{p-1}\;A_pu$ in D'(${\Omega}$) with $u\;\in\;K_p({\Omega})$. These inequalities are called Kato's inequalities provided that p = 2. The class of operators $A_p$ contains the so-called p-harmonic operators $L_p\;=\;div(\mid{{\nabla}u{\mid}^{p-2}{\nabla}u)$ for $A(x,\xi)={\mid}\xi{\mid}^{p-2}\xi$.

• The Journal of Internal Korean Medicine
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• v.34 no.3
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• pp.240-255
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• 2013

Objectives : This study was performed to research trends in Korean medicine treatment of diabetes mellitus (DM). Methods : We reviewed 73 studies about diabetes mellitus, which had been published from 2008 to 2013. The article search was performed on the Korean institute of oriental medicine (KIOM) database. Results : 1. Patterns of study design were as follows : 14 review studies, 44 experimental studies, 7 clinical studies, 8 case reports. 2. From the 14 review studies, we noted that literature studies about definition, pathologic mechanism, treatment, pathologic pattern identification of DM and previous study analyses were done. 3. From the 44 experimental studies that are the most common type of DM studies, various Korean medicine treatments such as single medicinal herbs, herbal complexes, diets and pharmacopuncture were used. Anti-diabetic effects were demonstrated in most of the studies. 4. 7 clinical studies about acupuncture, electroacupuncture, herbal medicine, etc. were reported. 5. 8 cases about DM complications and comorbidities were reported. Clinical symptoms improved in all of studies, blood sugar level decreased in four studies. Conclusions : Further clinical and case study based on experimental researches should be performed.

• Fibers and Polymers
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• v.4 no.3
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• pp.114-118
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• 2003

The prepolymer and the final polyurethane (PU) block copolymer were synthesized by reacting 4,4-methylene bis(phenylisocyanate) with poly(tetramethylene glycol) and the prepolymer with 1,4-butanediol as a chain extender, respectively, to investigate the relation between phase separation and it's resulting properties. According to FT-IR data, the phase separation of hard and soft segments in the prepolymer and the PU block copolymer grew bigger by increasing the hard segment content, and the PU showed more dominant phase separation than the prepolymer. The heat of fusion due to soft segments decreased in both the prepolymer and the PU by increasing the hard segment content, whereas the heat of fusion due to hard segments increased in the PU did not appear in the prepolymers. The breaking stress and modulus of the prepolymer increased by increasing the hard segment content, and the elongation at break decreased gradually, and the PU showed the highest breaking stress and modulus at 58% hard segment content. However, the best shape recovery of the PU was obtained at 47% hard segment content due to the existence of proper interaction among the hard segments for shape memory effect. Consequently, the mechanical properties and shape memory effect of the PU were influenced by the degree of phase separation, depending on the incorporation of chain extender as well as the hard segment content.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.281-292
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• 2014

Objectives: The aim of this case study is to verify the chemical exposure reductions for various chemicals by substituting the ingredients of raw materials in a polyurethane(PU) foaming industry. The PU foaming process was making various passenger car seats from chemicals such as toluene diisocinate(TDI), methylene bisphenyl isocyanate(MDI) and polyols. Methods: Basic process data and workers' health effects could be gathered by interviewing managers and reviewing previous exposure monitoring data. Amine, aldehyde and isocyanate chemicals were analyzed following the NIOSH-NMAM. Area sampling methods rather than personal sampling were introduced for this field investigation. Results: Two amines, triethylene diamine(TEDA) and N,N,N',N'-Tetramethyl-1,6- hexanediamine(TMHDA) were identified in raw polyol, cured PU foam and air. The average concentrations of TEDA and TMHDA showd less than 1 ppm by area sampling; however, that caused halovision among workers in PU-PAD process. Aldehydes and isocyanates were detected in the air while the concentrations were relatively low compare to occupational exposure limits. Successful raw material substitution from nonreactive amine to reactive amine could reduces air-borne amine and aldehyde levels by about 70%. Halovision had been disappeared successfully in the process. Conclusions: Several amines caused halovision among workers in PU-PAD process, especially during summer season in spite of relatively low levels. Combination of reactive amines into urethane foam could reduced vapor generation into air, which resulted in the elimination of eye troubles in the process.

• Journal of Korean Medicine Rehabilitation
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• v.21 no.2
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• pp.203-210
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• 2011

Objectives : The aim of this study is to establish evidence-based guideline on infrared therapy on acupoints. Methods : We investigated all the articles in websites including Pubmed, China national knowledge Infrastructure(CNKI) and medical journals authorized by national research foundation of Korea. The key words are acupoints and infrared. For the first time, we withdrew some papers no relationship to key words by reading titles and abstracts. In the second, we only selected randomized clinical trials(RCT) published from 2000 to 2010. Results : Out of 62 papers, only 2 RCT were analyzed. One (RCT 1) was about depression patients with insomnia(jadad score: 1). The other(RCT 2) was about urimic pruritus patients(jadad score: 5). In RCT 1, experimental group was significantly better than control group. In RCT 2, there was not statistical signification between two groups. Conclusions : In reality, there were not many papers on infrared therapy applications. Further study just like RCTs may be needed to establish evidenced-based guideline on infrared.

• Journal of Microbiology and Biotechnology
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• v.16 no.9
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• pp.1369-1376
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• 2006

Self-organized nanogels were prepared from pullulan/biotin conjugates (PU/Bio) for the development of an effective anticancer drug delivery system. The degree of biotin substitution was 11, 19, and 24 biotin groups per 100 anhydroglucose units of pullulan. The physicochemical properties of the nanogels (PU/Bio1, 2 and 3) in aqueous media were characterized by dynamic light scattering, transmission electron microscopy, and fluorescence spectroscopy. The mean diameter of all the samples was less than 300 nm with a unimodal size distribution. The critical aggregation concentrations (CACs) of the nanoparticles in distilled water were $2.8{\times}10^{-2},\;1.6{\times}10^{-2}$, and $0.7{\times}10^{-2}mg/ml$ for the PU/Bio1, 2, and 3, respectively. The aggregation behavior of the nanogels indicated that biotin can perform as a hydrophobic moiety. To observe the specific interaction with a hepatic carcinoma cell line (HepG2), the conjugates were labeled with rhodamine B isothiocyanate (RITC) and their intensities measured using a fluorescence microplate reader. The HepG2 cells treated with the fluorescence-labeled PU/Bio nanoparticles were strongly luminated compared with the control (pullulan). Confocal laser microscopy also confirmed internalization of the PU/Bio nanogels into the cancer cells. Such results demonstrated that the biotin in the conjugate acted as both a hydrophobic moiety for self-assembly and a tumor-targeting moiety for specific interaction with tumor cells. Consequently, PU/Bio nanogels would appear to be a useful drug carrier for the treatment of liver cancer.