In this study, nano-sized powder of Ni-ferrite was fabricated by spray pyrolysis process using the Fe-Ni complex waste acid solution generated during the shadow mask processing. The average particle size of the produced powder was below 100 nm. The effects of the reaction temperature, the inlet speed of solution and the air pressure on the properties of powder were studied. As the reaction temperature increased from 80 to 110, the average particle size of the powder increased from 40 nm to 100 nm, the fraction of the Ni-ferrite phase was also on the rise, and the surface area of the powder was greatly reduced. As the inlet speed of solution increased from 2 cc/min. to 10 cc/min., the average particle size of the powder greatly increased, and the fraction of the Ni-ferrite phase was on the rise. As the inlet speed of solution increased to 100 cc/min., the average particle size of the powder decreased slightly and the distribution of the particle size appeared more irregular. Along with the increase of the inlet speed of solution more than 10 cc/min., the fraction of the Ni-ferrite phase was decreased. As the air pressure increased up to 1 , the average particle size of the powder and the fraction of the Ni-ferrite phase was almost constant. In case of 3 air pressure, the average particle size of the powder and the fraction of the Ni-ferrite phase remarkably decreased.

Motor skill learning can be acquired implicitly without consciousness of what is being learned. The purpose of this study was to examine the characteristics of implicit motor learning in young and elderly people using a perceptual-motor task. Forty normal young and elderly subjects participated. A modified version of the Serial Reaction Time Task (SRTT) using six blocks of twelve perceptual motor sequences was administered. The paradigm consisted of the first random sequence block followed by the four patterned blocks and another random block. In each block, the go signal consisted of an asterisk displayed in the one of the four parallel arrayed boxes in the middle of the screen. Subjects were instructed to push the corresponding response buttons as quickly as possible. Young subjects demonstrated shorter reaction times during the consecutive patterned blocks reflecting appropriate learning accomplished. Elderly subjects were able to learn a perceptual-motor task with implicit knowledge, but the performance was lower than that of the young persons. These results indicated that implicit sequence learning is still preserved in elderly adults, but the rate of learning is slower.

Every human action concerning to human brain contains the time between the brain decision and the action, so it is very difficult for Scientists, who study about human, especially Ergonomist, to get correct analysis. This study, therefore, had an experiment to get a time during taking some action, which does not ask any brain work called human basic reaction time. Then, the result of this study can be used to have much more correct data analysis from your experiment by removing the time we do not need. Especially, this study deals with the basic reaction time of old people to compare with young age which took before by us, and we want to know the relation between the age and their basic reaction time.

A formation of aluminum hydroxide by hydrolysis reaction in the water has been studied by using nano aluminum powder fabricated by pulsed wire evaporation(PWE) method. The hydroxide type and morphology depending on temperature and pH were examined by structural analysis. The Boehmite(. or AIO(OH)) was predominantly formed in high temperature region over 4, while the Bayerite(. or ) below of hydrolysis temperature. The Boehmite formation was preferred to the Bayerite in acidic solution in the same hydrolysis temperature. The slowly formed Bayerite phase showed facet crystalline structure, while the fast formed Boehmite was fine fiber with a large aspect ratio of several nm in diameter and several hundred nm in length, and with much larger specific surface area(SSA) than that of Bayerite. The highest SSA was about /g.

The catalytic oxidation reaction of several cycloolefins in CH2Cl2 have been investigated using non-redox metalloporphyrin(M = Ga(III), In(III) and TI(III) complexes as a catalyst and sodium hypochlorite as a terminal oxidant. Porphyrins were (p-CH3O)TPP, (p-CH3)TPP, TPP, (p-F)TPP, (p-Cl)TPP and (F20)TPP (TPP=5,10,15,20-tetraphenyl-21H,23H-porphyrin) and olefins were cyclopentene, cyclohexene, cycloheptene and cyclooctene, The substrate conversion yield(%) was investigated according to the radius effect of non-redox metal ion, substituent effect and hindrance effect of metalloporphyrin. The conversion yield of cycloolefin was in the following order : C5 〈 C6 〈 C7 = C8.

근래에 들어 질병으로 인하여 의사표현이 곤란한 환자에게 뇌파에 기초한 BCI(Brain Compute, Interface)와 같은 새로운 인터페이스를 제공하고자 하는 연구가 활발히 진행되고 있다. 특정 자극에 대해 유발되는 뇌파의 측정과 분석은 BCI를 위한 뇌파의 패턴과 인터페이스의 설계에 중요한 역할을 한다. 이 연구의 목적은 시청각 자극 인가 후 피험자의 반응시간을 측정하는 시스템을 EEG와 같은 생체 신호 계측 시스템과 연동이 가능한 형태로 개발하는 것이다. 제안된 시스템은 기능적으로 자극신호 발생부, 반응시간 측정부, 유발뇌파 측정부, 동기신호 발생부로 나뉘어진다. 자극신호 발생부는 실험에 이용되는 자극신호를 제작하는 부분으로서 Flash를 사용하여 구현하였다. 반응시간 측정부는 문제에 대한 답 선택 요청시각으로부터 피험자의 반응까지의 시간을 측정하는 부분으로서 마이크로컴퓨터를 이용하여 구현하였다. 유발뇌파 측정부는 시판용 하드웨어와 소프트웨어를 그대로 사용하였다. 동기신호 발생부는 전체 시스템의 동기를 맞추기 위한 신호를 발생하는 부분으로서 문제제시, 답 요구와 동기한 화면상의 명암신호와 이를 검출하는 광센서로 구성하였다. 본 논문에서 제시한 방법에서는, 기존의 유발전위 측정 및 자극시스템에 특정 모듈(반응시간 측정 장치, 동기신호 발생장치)만을 추가하여 실험자의 의도에 맞는 시스템을 설계할 수 있어 유발응답 및 반응시간의 측정을 필요로 하는 연구를 가속화 할 것이 기대된다.

Two types of carbon fiber based high modulus- and isotropic-pitch were exposed to isothermal oxidation in air and CO2 gas and the weight change was measured by TGA apparatus. The kinetic equation was introduced f=1--(-atb) and the constant b was obtained in the range of 1.02~1.68 for the isotropic fiber and obtained 0.91~1.93 for the high modulus fiber respectively. In considering the effect of the atmosphere for isothermal oxidation, the value of the constant b obtained in the carbon dioxide was higher than that obtained in the air. Therefore, it was found that the pitch based carbon fiber shows sigmoidal characteristic when it is oxidized in the carbon dioxide. In addition, it was also found that kf = 0.5, which was reaction constant at f = 0.5, was a very useful parameter for evaluation of the oxidation reactivity of pitch based carbon fibers. According to the consideration, it is suggested that the conversion-time curves of the pitch based carbon fibers are correlated by normalized equation f=1--(-AτB), where τ=t/tf= 0.5.

Water-soluble cutting fluids are used for processing of aluminium materials. This short article describes properties of new additives of water-soluble cutting fluids for aluminium materials. Various Diels-Alder adducts of unsaturated fatty acids with acrylic acid of maleic anhydride were prepared by thermal reactions. Triethanolamine salts of Diels-Alder adducts of dehydrated castor oil fatty acids with acrylic acid or maleic anhydride showed excellent anti-corrosion property of aluminium materals. These thermal adducts showed anti-rust property for cast-iron chips, too.

불완전 분리의 실질적인 분리투과 특성을 근거로 하는 모사모델을 이용하여 투과증발 막촉진 에스터화 반응의 실질적인 거동을 연구하였다. 막의 분리효율, 막의 물제거 능력을 모델에 포함시킴으로써 반응모사를 통하여 이들이 막촉진반응에 어떻게 영향을 끼치는지를 체계적으로 관찰할 수 있었다. 막을 통한 비완전분리가 일어날 경우에 초기 반응물 몰비율이 1이 아닐 때 반응 혼합물중 소량으로 존재하는 반응성분이 투과되거나, 혹은 초기 반응물 몰비율이 1인 반응 혼합물중 어느 반응성분이 투과되든지 반응이 완결될 수 없었다. 생성물인 에스터가 물과 함께 일부 투과될 경우 정방향 반응속도를 증가시켜 시간에 따른 반응 전환률을 증가시킨다. 막을 통한 불완전 분리시 막을 통한 투과로 인하여 발생하는 반응혼합물의 부피감소로 인하여 반응성분 뿐 아니라 생성성분의 농도가 증가되는데 이들 농도증가가 반응속도에 상반된 영향을 끼친다; 반응물 농축은 반응속도를 증가시키나 생성물 농축은 역방향의 반응을 촉진시킴으로서 반응속도를 감소시킨다. 반응초기에는 반응물 농축효과가 우세하나 반응이 진행됨에 따라 생성물 농축효과가 우세하여 반응속도를 저하시킴이 모사결과 관찰되었다.

본 연구는 인간의 정신부하작업중 반응시간이 제한된 긴급상황에서 시스템이 비정상적인 상태로 변화할 경우 인간의 수행도 특성을 살펴보고 이를 보조할 수 있는 보조장치의 설계에 도움을 주는 기준안을 제시하고자 한다. 긴급상황에서의 최우선시 되는 수행도는 반응시간보다는 시스템을 성공적으로 제어하여 비극적인 재해를 방지하는 일이다. 그러므로 여러 작업 수행도들 중에서 제어에 실패하게 되는 요인의 영향도를 알아내는 것이 중요하다. 실험결과 인간의 반응은 극히 제한된 짧은 반응시간내의 수행도는 단일작업에서의 수행도는 시스템의 전체 영향도를 제대로 반영하지 못함을 알 수 있었다. 이럴 경우 부수작업을 부여했을 때 시스템의 변화 요인의 영향도를 더욱 잘 나타내는 것임을 유도하였다. 그러므로 시스템의 상황이 비 정상적인 상태로 진행될 경우, 특히 이러한 상황에서 반응해야 할 시간이 제한적일 경우 수행도 측정에는 다양한 형태의 부수작업을 개발하고 이를 이용한 측정이 더욱 효율이 있다는 점을 제시한다.. 이러한 실험의 결과를 유추해보면 안전장치 기기의 설계를 위해서는 운용되는 상황에 맞는 측정방법이 개발되어야 긴급 상황의 수행도를 측정할 수 있다.

Oxidized polyethylene wax is obtained by oxidation of polyethylene wax and it is composed of various chemicals, e.g., fatty acid, alcohol, ketone and ester. The application of oxidized polyethylene wax is determined by the composition of these chemical substances. In this basic study we observed the basic reaction parameters of time, temperature, oxygen concentration and catalysts on the oxidation reaction of low molecular weight polyethylene(PE wax) by analyzing the acid value, physical and chemical properties of oxidized PE wax to develop a new oxidation process. Acid values are increased with temperature increase in the rage of 150℃~180℃ but decreased beyond 190℃. Acid values are also increased with oxygen concentration. As the oxidation reaction proceeds the molecular weight and softening points of oxidation products are decreased by cracking reaction, but the viscosities are increased. To observe the crystallinity of oxidation products SEM experiment was performed. To obtain a high acid-value product in a mild condition, we adopted free radical catalysts and the acid value of the product using catalyst was higher than the product obtained without catalyst in the same reaction condition. The effective initiators were dicumyl peroxide(DCPO), t-butylperoxy-2-ethyl hexanoate(HOPO) and benzoyl peroxide(BPO) having long half-life.

본 연구는 인간의 물리적인 요소(머리너비, 가슴너비, 팔길이 등)에 따른 반응속도의 변화에 대해 다룬다. 본 연구에 따르면, 머리 앞뒤 너비나 팔길이 등의 요소들은 반응속도에 영향을 미치지 않았으나, 너비에 해당하는 요소들은 인간의 반응속도에 영향을 미치는 것으로 평가되었다. 본 연구의 결과는 특수상황에 보다 우수한 작업자를 선정하거나, 운동선수를 테스트 없이 우선적으로 선정하는 데 사용될 수 있다. 또한, 본 연구의 결과는 인간정보전달 경로상의 노이즈라고 명명된 채널 노이즈와 시간과의 관계를 규명하기 위한 채널 노이즈 타임분석을 위해 사용될 수 있다.