• 대한화학회지
• /
• 제44권3호
• /
• pp.266-280
• /
• 2000

본 연구에서는 일반화학 학습의 맥락을 형성하는 대학생의 개념생태를 알아 보고자하였다.연구는 1999년도 1학기에 일반화학을 수강하는 1학년 학생들 9명을 대상으로 하여 정성적 방법으로 수행 되었다. 연구 자료는 3차에 걸친 면담, 수업 직접관찰, 여러 번의 퀴즈와 중간${\cdot}$기말 시험, 그리고 학생들이 작성한 수필 형식의 글과 수업관찰 일지에서 수집 되었다. 연구자는 3 성분 분석 방법에 따라 자료를 연구 참여자별로 분석하고, 이를 상호 비교하였다. 연구의 결과,개념 생태는 크게 인식론적 관점,동기적 신념,사회-문화적 가치의 세 범주로 나뉘어졌다. 이들 개념생태의 세 범주 중에서도 특히, 동기적 신념과 사회 선회적 가치의 범주가 일반화학 학습에 중요한 영향을 미치고 있는 것으로 나타났으며, 그 결과를 전형적인 사례 연구로 제시하고 화학학습 접근법을 살펴보았다.

• Bulletin of the Korean Chemical Society
• /
• 제4권3호
• /
• pp.103-114
• /
• 1983

The NMR shift arising from the electron angular momentum and the electron spin dipolar-nuclear spin angular momentum interaction has been examined for a $3d_1$ system in a strong octahedral crystal field when the threefold axis is chosen as the quantization axis. To investigate the NMR shift in this situation, first, we have extended the evaluation of the hyperfine integrals to any pairs of 3d orbitals adopting a general method which is applicable to a general vector R, pointing in arbitrary direction in space. Secondly, a general expression using a nonmultipole technique is derived for the NMR shift resulting from the electron angular momentum and the electron spin dipolar-nuclear spin angular momentum interactions. From this expression all the multipolar terms are determined. ${\Delta}B/B$ for the $3d_1$ system in this case is compared with that for the 3d1 system when the z axis is chosen as the quantization axis. When we choose the threefold axis as the quantization axis, it is found that along the , and axes, ${\Delta}B/B$ values are significantly different from each other and along the , <-1-1-1>, <-11-1>, , <-1-11>, , and <-111> axes, ${\Delta}B/B$ values are however the same. We also find that the 1/R7 term contributes dominantly to the NMR shift for all values of R. When 1/$R^5$ term is included, there is good agreement between the exact solution and the multipolar terms when $R\; {\leqslant}\;0.35\;nm.$.

• 진공이야기
• /
• 제2권3호
• /
• pp.4-10
• /
• 2015

We developed a real-time three-polarizer spectroscopic ellipsometer based on a new data acquisition algorithm and a general data reduction (the process of extracting the ellipsometric sample parameters from the Fourier coefficients). The data acquisition algorithm measures Fourier coefficients of radiant flux waveform accurately and precisely. The general data reduction is introduced to represent the analytic functions of the standard uncertainties of the ellipsometric sample parameters, and the extracted theoretical values closely agree with the corresponding experimental data. Our approach can be used for optimization of measurement conditions, instrumentation, simulation, standardization, laboratory accreditation, and metrology.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1996년도 추계학술대회 논문집
• /
• pp.56-60
• /
• 1996

An experimental study on the grinding temperature and Acoustic Emission(AE) signals due to the different shapes of wheel was conducted. The grinding characteristics by slotted shapes of wheel changed by width and helical angle, were compared with those by general one. Lower grinding temperature was obtained for 30$^{\circ}$ helical angle with 10mm width, Root Mean Square(RMS) values of AE signals were higher for slotted wheel rather than general one.

• 한국멀티미디어학회논문지
• /
• 제18권8호
• /
• pp.960-967
• /
• 2015

In this paper, we propose a user interface technique based on embedded sensors applying to apps in smart phone. Especially, we implement avata generation application using image filtering technique for photo image in smart phone. In the application, The embedded sensors are used as intuitive user interface to adjust the image filtering effect for making user satisfied effect in real time after the system produced the image filtering effect for avatar. This technique provides not a simple typed method of parameter values adjustment but a new intuitively emotional adjustment method in image filtering applications. The proposed technique can use sound values from embedded mike sensor for adjusting key values of sketch filter effect if the smart phone user produces sound. Similiarly the proposed technique can use coordinate values from embedded acceleration sensor for adjusting masking values of oil painting filter effect and use brightness values from embedded light sensor for adjusting masking values of sharp filter effect. Finally, we implement image filtering application and evaluate efficiency and effectiveness for the proposed technique.

• 약학회지
• /
• 제45권3호
• /
• pp.251-257
• /
• 2001

The study was carried out to evaluate the preliminary toxicity and general pharmacology of KML-IIU, a purified pectin from Korean Mistletoe (Viscum album coloratum). KML-IIU was administered intravenously to ICR mice and Spargue-Dawley rats to investigate the acute toxicity. LD50 values in mice and rats were above 30 $\mu$g/kg. KML-IIU had no effects on the general behaviors, acetic acid induced writhing syndrome, pentobarbial induced sleeping time, pentylenetetrazole induced convulsion and the change of body temperature. In addition, KML-IIU did not show any effects on digestive system and blood coagulation system.

• International Journal of Control, Automation, and Systems
• /
• 제1권1호
• /
• pp.127-133
• /
• 2003

This paper proposes a new numerical method to check the stability of a general class of time delay systems. The proposed method checks whether there are characteristic roots whose real values are nonnegative through two steps. Firstly, rectangular bounds of characteristic roots whose real values are nonnegative are computed. Secondly, the existence of roots inside the bounds are checked using the numerical computation of argument principles. An adaptive discretization is proposed for the numerical computation of argument principles.

• Journal of applied mathematics & informatics
• /
• 제33권3_4호
• /
• pp.305-315
• /
• 2015

Recently, Jianxin Liu, Hao Pan and Yong Zhang in [On the integral of the product of the Appell polynomials, Integral Transforms Spec. Funct. 25 (2014), no. 9, 680-685] established an explicit formula for the integral of the product of several Appell polynomials. Their work generalizes all the known results by previous authors on the integral of the product of Bernoulli and Euler polynomials. In this note, by using a special case of their formula for Euler polynomials, we shall provide several reciprocity relations between the special values of Tornheim's multiple series.

• 전기의세계
• /
• 제21권4호
• /
• pp.7-14
• /
• 1972

The author has established a general equation for the travelling magnetic field in air gap with the end effect taken into consideration, which constitutes the basics for the analysis of characteristics of linear induction motor. This equation is verified by comparison of the experimental values with the theoretically calculated values. The properties of the travelling wave with attenuation, which is contained in the travelling magnetic field of linear induction motor, have been verified, and consequently the practicable equation is established with these effects taken into consideration. This provides the solid foundation for the theoretical analysis of the characteristics of the linear induction motor.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
• /
• pp.353-360
• /
• 1998

Dynamic measurements are used rather sparingly to determine the elastic moduli of rock cores and modulus values are not much utilized in design practice. The reason seems to result from the general perception that values obtained by dynamic measurement are much higher (about 10 times) than those determined statically. This paper presents results from dynamic and static tests on rock cores. The findings are : 1) elastic moduli can be consistently determined by laboratory seismic testing. 2) nonlear deformation characteristic of rock cores was tentatively proposed with variation in elastic modulus with strain.