• Journal of Pharmaceutical Investigation
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• 제24권4호
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• pp.273-279
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• 1994

The stability of three oximes, Hl-6 [(4-carbamoyl-2'[(hydroxyimino)-methyl]- 1,1'-oxydimethylenedi-(pyridinium chloride)], Hl-CN [(4 cyano-2'-[(hydroxyimino)-methyl] -1,1'-oxydimethylene-di-(pyridinium chloride)], and 2-PAM [pralidoxime chloride] in aqueous solutions was evaluated by HPLC assay. The rate of degradation is dependent on the pH as well as the temperature at which the solution is stored. The optimum pH for the stability of these oximes was pH 2 to 3. The degradation rate constant for 2-PAM ($k\;at\;70^{\circ}C$, $2.07{\times}10^{-4}/hr;\;E_a\;value$, 27.2 kcal/mol) was smaller than those for bis-pyridiniumoximes, Hl-6 ($k\;at\;70^{\circ}C$, $3.38{\times}10^{-3}/hr$) and Hl-CN ($k\;at\;70^{\circ}C$, $8.66{\times}10^{-3}/hr;\;Ea\;value$, 20.7 kcal/mol). In mechanistic analyses, it was found that Hl-CN was decomposed through not only the hydrolysis of nitrile group but also the cleavage of methylene ether bridge, in contrast to Hl-6 which was degraded mainly through the cleavage of methylene ether bridge.

• Journal of Mechanical Science and Technology
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• 제15권7호
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• pp.982-994
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• 2001

Commercially available software packages permit to position human models of various geometries in practical scenarios while respecting the anatomical constraints of the skeletal joints and of the bulk of the bodies. Beyond such features, the PAM-Comfort(sup)TM software has been conceived to provide direct access to the muscular forces needed by humans to perform physical actions where muscle force is required. The PAM-Comfort(sup)TM human models are made of multi-body linked anatomical skeletons, equipped with finite elements of the relevant skeletal muscles. The hyper-static problem of determination of muscle forces is solved by optimisation technique. Voluntary stiffening of muscles can be added to the basic contraction levels needed to perform a specific task. The calculated muscle forces obey Hills model. The model and software have been applied in several interesting scenarios of various fields of application, such as car industry, handling of equipment and sports activities.

• 펄프종이기술
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• 제31권2호
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• pp.34-41
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• 1999

Adsorption of cationic polyacrylamide dry strength resins onto the surface of papermaking fibers and fines is critical for their effective utilization. Since dry strength resins are frequently employed when recycled fibers containing a great deal of fines are used as a raw material, their adsorption characteristic onto the recycled fiber fines is of great importance. In this study, effects of recycling on adsorption characteristics of cationic polyacrylamide onto primary and secondary fines were examined. Never dried bleached hardwood kraft pulp was beaten and dried for recycling. In each recycling step the adsorption characteristic of a cationic PAM onto primary and secondary fines was evaluated by kjeldahl nitrogen analysis method. The influence of recycling on water retention value and carboxyl content along with the sheet density and tensile strength was examined. Secondary fines of never dried pulp adsorbed twice as much of C-PAM as the primary fines, however, the adsorption capacity of the secondary fines decreased rapidly during the course of recycling and showed lower adsorption capacily than primary fines.

• 대한생식의학회:학술대회논문집
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• 대한불임학회 2001년도 제41차 추계학술대회
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• pp.109.2-109.2
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• 2001

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 춘계학술발표논문집
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• pp.1-7
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• 2006

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 총회 및 춘계학술발표회
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• pp.227-230
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• 2004

본 연구에서는 유류오염토양 세척유출수내 미세토사의 효율적 제거를 위한 최적의 방안 및 적용 운전 조건을 도출하고자 하였다. 응집제를 주입하지 않은 blank 실험결과, 광운대학교 토양 세척유출수는 pH 7～12의 범위에서 65～75%의 효율을 나타내었고, 우이천 하천퇴적 토양 세척유출수는 pH 7～11의 범위에서 30% 안팎의, pH 12에서는 70% 정도의 낮은 효율을 나타내었다. pH 13에서는 두 가지 세척유출수에서 각각 91%, 85%의 효율을 나타내었다. 응집ㆍ침전 실험 결과, 광운대학교 토양 세척유출수는 FeC13, alum, PAC을 적용하였을 때 대체로 99% 이상의 효율을 보였으나, PAM을 적용하였을 때는 pH 13에서만 약 95%의 효율을 보였을 뿐 pH 7～12의 범위에서는 50～70%의 낮은 효율을 보였다. 우이천 하천퇴적 토양 세척유출수는 alum과 PAC을 적용하였을 때 대체로 90% 이상의 효율을 나타내었으나, FeC13와 PAM을 적용하였을 때는 pH 13일 경우에서만 98%이상의 효율을 보였을 뿐 다른 pH조건에서는 대체로 60%이하의 효율을 보였다. 두 가지 세척유출수에 대하여 높은 효율을 보인 alum과 PAC의 경제성을 비교해본 결과 같은 양의 세척유출수를 응집처리 할 경우 PAC에 비하여 alum을 적용하였을 때 적은 비용이 소요되었다. 따라서 alum이 효율성과 경제성에서 가장 우수함을 알 수 있었다.

• 한국건축시공학회지
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• 제2권3호
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• pp.131-138
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• 2002

The objective of the study is to examine the characteristic correlations between reinforcing carbon fiber and interfacial adhesion agent since the interfacial adhesion strength between reinforcing carbon fiber and matrices is believed to be an essential element influencing the physical properties in carbon fiber reinforced cement composite using slurry method. The integrity of interfacial adhesion between reinforcing fiber and cement not only affects the quality of fiber reinforced cement composite but also influences to a large degree the physical properties of the cement composite when producing carbon fiber reinforced cement composite using slurry method. Having analyzed the physical properties 1.e., water content, tensile strength, flexural strength and flexural toughness of carbon fiber reinforced cement composite specimens, C-PAM(cation polyacrylamide) was determined to be an optimum interfacial adhesion agent. The study has also demonstrated that interfacial adhesion strength varies largely on the content and type of the reinforcing fiber. Judging from magnified view of the tensile shear cross-section using VMS(video microscope system), interfacial adhesion strength between reinforcing fiber and matrices is affected by the type of interfacial adhesion agent. According to the result of the experiments, C-PAM was determined to be an ideal interfacial adhesion agent when using carbon fiber in producing carbon fiber reinforced cement composite with the optimum content of carbon fiber being established.

• 한국해양학회지:바다
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• 제14권2호
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• pp.118-126
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• 2009

저서규조류는 하구역 먹이망을 이해하는 데 중요한 생물로서 그들의 광생리 특성에 따라 일차생산력이 크게 변화한다. 본 연구에서는 단기간 온도 변화가 저서규조류 4종(Navicula sp., Nitzschia sp., Cylindrotheca closterium, Pleurosigma elongatum)의 광합성 반응에 미치는 영향을 Diving PAM을 이용한 엽록소 형광 분석법으로 측정하여 광생리 특성을 분석하였다. 6개의 온도 조건(10, 15, 20, 25, 30, $35^{\circ}C$)에서 2시간 간격으로 24시간 동안 엽록소 형광을 측정하여 P-I 곡선을 도출하였다. 제2광계의 유효양자수율($\Phi_{PSII}$)은 대부분의 종에 있어서 온도가 증가함에 따라 감소하였으며, 상대 최대 전자전달율(rETRmax)은 최적 온도까지 증가한 후 급격하게 감소하였다. 최대 빛이용 효율($\alpha$)은 다른 광합성 매개변수에 비해 온도에 덜 민감하였으나, 높은 온도에서는 감소하였으며, 광포화 계수($E_K$)는 상대 최대 전자전달율의 반응과 매우 유사하였다. 종별 광생리 특성을 분석한 결과, Navicula sp.와 Cylindeotheca closterium가 광생리적 조절을 통하여 단시간의 온도 변화에 광순응하는 것을 확인할 수 있었다.

• Macromolecular Research
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• 제13권2호
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• pp.135-140
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• 2005

Poly(vinyl alcohol) (PVA) membranes crosslinked with poly(acrylic acid-co-maleic acid) (PAM) were prepared to investigate the effect of aging on their morphology by swelling them for up to 7 days. PAM was used both as a crosslinking agent and as a donor of the hydrophilic-COOH group. A $30 wt\%$ weight loss of the dry membrane was observed in the swelling test after 6 days. The surface of the membrane was dramatically changed after the swelling test. The surface roughness of the PVA/PAM membrane was increased, as determined by atomic force microscopy (AFM). The swelling loosened the polymer structure, due to the release of the unreacted polymer and the decomposition of the ester bond, thereby resulting in an increase in the free volume capable of containing water molecules. The water molecules present in the form of free water were determined by differential scanning calorimetry (DSC). The fraction of free water increased with increasing swelling time. The swelling of the membrane may provide space for the transport of protons and increase the mobility of the protonic charge carriers. The proton conductivity of the membranes measured at T= 30 and $50^{\circ}C$ was in the range of $10^{-3} to 10^{-2} S/cm$, and slightly increased with increasing swelling time and temperature.

• 펄프종이기술
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• 제47권2호
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• pp.53-60
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• 2015

The effects of stirring speed during filler modification by dual polymers on flocculation and reflocculation of PCC (precipitated calcium carbonate) particles and its effect on handsheet properties were elucidated. PCC surface was modified by adsorbing A-PAM (anionic polyacrylamide) and C-starch (cationic starch) in series at various stirring speeds. It was found that increasing stirring speed during filler modification decreased the initial floc size of PCC. Continuous stirring with the same speed for filler modification resulted in the decrease of a floc size, eventually reached a steady state. The variations in a floc size was influenced by the stirring speed during filler modification: the lower the stirring speed during filler modification, the larger the floc size variations. Conclusively, the stability of PCC floc could be improved by increasing the stirring speed. In addition, the stirring speed influenced the handsheet properties. The smaller the PCC floc, the lower the strength of handseet. However, too much larger floc size also deteriorated paper strength. There exists an optimum floc size in term of paper strength which shall be controlled by stirring speed during filler modification.