We model dust around Herbig Ae/Be stars using a radiative transfer model for multiple isothermal circumstellar dust shells to reproduce the multiple broad peaks in their spectral energy distributions (SEDs). Using the opacity functions for various types of dust grains at different temperatures, we calculate the radiative transfer model SEDs for multiple dust shells. For eight sample stars, we compare the model results with the observed SEDs including the Infrared Space Observatory (ISO) and AKARI data. We present model parameters for the best fit model SEDs that would be helpful to understand the overall structure of dust envelopes around Herbig Ae/Be stars. We find that at least four separate dust components are required to reproduce the observed SEDs. For all the sample stars, two innermost dust components (a hot component of 1000-1500 K and a warm component of 300-600 K) with amorphous silicate and carbon grains are needed. Crystalline dust grains (corundum, forsterite, olivine, and water ice) are needed for some objects. Some crystalline dust grains exist in cold regions as well as in hot inner shells.

The fabrication of Fe alloy-40 wt.%TiC composite materials using spark plasma sintering process after ball-milling was studied. Raw powders to fabricate Fe alloy-TiC composite were Fe alloy, and activated carbon. Fe alloy powder was Distaloy AE (4%Ni-1%Cu-0.5%Mo-0.01%C-bal.%Fe) made by Hoeganes company with better toughness and lower melting point. These powders were ball-milled in horizontal attrition ball mill at a ball-to-powder weight ratio of 30 : 1. After that, these mixture powders were sintered by using spark plasma sintering apparatus for 5 min at in vacuum atmosphere under torr. DistaloyAE-40 wt.%TiC composite was directly synthesized by dehydrogenation and carburization reaction during sintering process. The phase transformation of as-milled powders and sintered materials was confirmed using X-ray diffraction (XRD) and transmission electron microscope (TEM). The density and harness materials was measured in order to confirm the densification behavior. In case of DistaloyAE-40 wt.%TiC composite retained for 5 min at , it has the relative density of about 96% through the influence of rapid densification and fine TiC particle reinforced Fe-based composites materials.

Increased complexity of products and their manufacturing processing demans higher quality control and monitoring than ever before. Therefore, flexible automatization or flexible manufacturing systems (FMS) offer numerous advantages over alternative manufacturing methods. In this state, a in-process monitoring is one of the important flexible automatino system. And as use of NC and CNC machine tool has been increasing, cutting work has automating and it is necessary to develop the automatic production system combined a couple of machine tool. Thus, in this paper to search examination it can measure the tool wear and the tool life and can be more practical research subject.

Increased complexity of products and their manufacturing processing demans higher quality control and monitoring than ever before. Therefore, flexible automatization or flexible manufacturing systems (FMS) offer numerous advantages over alternative manufacturing methods. In this state, a in-process monitoring is one of the important flexible automation system. And as use of NC and CNC machine tool has been increasing, cutting work has automating and it is necessary to develop the automatic production system combined a couple of machine tool. Thus, in this paper to search examination it can measure the tool wear and the tool life and can be more practical research subject.

Circumstellar peculiarities of the young Herbig Ae/Be stars are analyzed using high-resolution CCD spectroscopic data, obtained in 1991-1996 at the ESO and the Crimean Astrophysical Observatory (about 450 spectrograms). The results of investigation of the rapid line variability in Hα, Hβ, HeI 5876 and DNaI lines are presented for AB Am, HD 163296, HD 36112, HD 100546, and HD 50138. We conclude that the behaviour of these lines can be explained in the framework of the model containing an equatorially concentrated and azimuthally inhomogeneous stellar wind, and an external cool shell that occasionally looses matter in form of infall onto the star.

본 연구는 화강암 폐재의 재활용을 목적으로 한 기초적인 연구로서, 분말형태의 화강암폐재를 Ca(OH2)와 혼합하여 수열 hot press 법에 의해 고화시켰다. 아울러 고화체의 기계적 성질을 평가하였으며, 미시적 조직구조의 변화 및 파괴거동을 파악하기 위해 음향방출실험을 실시하였다. 고화체의 기계적 성질은 수열온도의 의존성이 있었으며, 280˚C에서 최대강도를 보였다. 또한 고화체의 파면은 수열온도에 따라 현저히 다른 양상을 보였으며, 수열실험동안 다양한 화합물이 생성되었다. 그 중에서 cyclowollastonite, tobermorite 및 rankinite 등은 강도를 향상시키는 주된 화합물이었고, crossite 및 xonotlite 등은 강도의 저하를 초래하였다. 한편, 기공이 많이 존재할수록 AE counts는 더많이 발생하였으며, 최대하중에서 AE counts는 최대치를 보였고, 강도가 증가함에 따라 AE신호는 보다 많이 방출되었다.

The structural integrity of concrete silos is important from the perspective of long-term operation of radioactive waste repository. Recently, the application of acoustic emission (AE) is considered as a promising technology for the systematic real-time health monitoring of concrete-like brittle material. In this study, the characteristics of AE wave propagation through concrete silo of Gyeongju radioactive waste repository were evaluated under the effects of groundwater and temperature for the quantitative damage assessment. The attenuation coefficients and absolute energies of AE waves were measured for the temperature cases of 15, 45, 75°C under dry and saturated concrete specimens, which were manufactured based on the concrete mix same as that of Gyeongju concrete silo. The geometric spreading and material loss were taken into account with regard to the wave attenuation coefficient. The attenuation coefficient shows a decreasing pattern with temperature rise for both dry and saturated specimens. The AE waves in saturated condition attenuate faster than those in dry condition. It is found that the effect of water content has a greater impact on the wave attenuation than the temperature. The results from this study will be used as valuable information for estimating the quantitative damage at the location micro-cracks are generated rather than the AE sensor location.

Acoustic Emission (AE) technique applied to detect the crack occurrence of the actual beam element. An optimum position for a limited number of AE transducer was considered to accurately detect the location of the cracks in the three-dimensional space. Six AE transducer was used to detect cracks in the L400mm×H200mm×T100mm region, and several position combinations were applied. Considerable six position combinations were selected, and the weak or incorrect position detection was investigated. The optimum position applied to the experiment for actual beam element and the detected crack position was compared with the visual inspection location. A reliable crack position detecting was confirmed for loadings.

In case of cable supported bridges, the cable system is a very important element that transfers the load of the girder to the pylon or substructure is the most important feature. The safety management of these cable systems is very important because they are directly linked to the safety of the entire bridge. This paper presents the applicability of the acoustic emission (AE) method is one of the non-destructive evaluation methods, is evaluated for the detection and monitoring of bridge cable damage. In order to verify the performance of the cable inspection method using the AE sensor, experiments were conducted. As a result, it is considered that the acoustic emission technique will be able to detect corrosion breakage and signs of rupture of cables if sufficient database of AE signal with various environmental conditions is secured.

In this study, a series of studies is intended to elicit the improvement of the quality of Admixture Substitute Concrete using oil refined for petrochemical work (ERCO). In other words, ERCO is used to analyze the basic properties of Admixture Substitute Concrete by pre-adding the AE liquid solution on its products. As an experimental variable, the method of adding ERCO was added after mixing it with concrete. In addition, the mixing ratio was planned to be 2 levels of 0, 0.5 %, and the total volume of the AEs injection quantity is 5 % that combines 0, 1, 2, and 3 % of the mixed ERCO mass of concrete. As a result, as the pre-injection of AE was increased, the characteristics of the concrete showed that the slump, and air contents were not improved, and the pre-adopting effects of AE agent were also significantly increased in the concrete.

This paper aims to develop the AE non-destructive testing equipment and signal analysis method for external tendon of PSC (Pre-Stressed Concrete) bridge. The AE NDT equipment, which has developed in this research, is composed of AE sensor, signal receiver, hitting device, driving part and main frame. Defective and non-defective specimens, designed to emulate signal characteristics for external duct with void(25%, 50% and 100%) or not, were constructed and tested to verify the effectiveness of AE NDT equipment. Test results and AE parameters comparisons between defective and non-defective specimens are presented.

蒼崖 許萬璞(1866~1917)은 진주 지역에서 활동한 한말의 유학자 이다. 武科에 급제하여 잠시 武人으로 살았으나, 외세의 침략과 문란한 정치 현실에 비분강개하여 스스로 관복을 벗어던지고 고향인 진주 지 수 승산마을로 낙향하였다. 그리고 세상을 마칠 때까지 은둔하다시피 하면서 經史를 탐구하고 스승을 찾아다니며 도학을 강론하였다. 본고 는 그 동안 연구가 이루어지지 않았던 진주 지역의 한말 유학자 창애 허만박을 주목한 것이다. 이 글에서는 허만박의 문집을 토대로 그의 삶을 보다 세밀하게 추적해보고 그 자취를 담고 있는 한시를 검토 분석 하여 그의 내면의식을 따라가 보고자 했다. 52세의 나이로 비교적 짧은 생을 살다간 허만박은 선조들의 행적이 그러하듯 젊어서부터 은거 지 향적 면모를 보이다가 무과 급제 후 관직에 진출해 서울 생활을 시작했 다. 그러나 서울에서 보고 겪은 외세의 침략과 국가적 위기에 그는 절망 하고 스스로 사직하였다. 그리고 고향으로 내려가 승산 마을의 염창강 가에 은둔하면서 도학의 근본 탐구에 골몰하며 절의를 실천하고자 하 였다. 1905년 을사조약의 체결로 인해 스승 송병선을 잃은 허만박은 이후 송병순과 최익현, 전우를 차례로 스승으로 모시며 도학을 강론하 고 자제와 후진 교육에 힘을 쏟았다. 이 시절 그는 상소문과 편지 또는 제문에서 혼란하고 무력한 정치 현실과 일본의 침략에 대해 비분강개 하며 통탄과 憂國의 심정을 드러내기도 했지만 그와 동시에 거듭되는 집안의 불행으로 위축된 모습과 하루하루 견디는 심정을 표출하기도 했다. 삶의 이력으로 볼 때 그는 폭넓은 교유 관계를 형성하기는 어려웠 던 것으로 보인다. 허만박은 자신이 살았던 智水 勝山 마을의 山水를 대상으로 삼아 시를 많이 지었다. 더불어 인근 주변 지역의 승경이나 또는 자연 속의 구체적인 사물들에 대해서도 시적 감수성을 발휘해 시를 짓는 계기로 삼았다. 물론 한시에 묘사된 산수 자연은 허만박의 삶의 흐름과 그에 따른 정서가 스며들면서 시기에 따라 다른 느낌과 이미지를 전달하고 있다. 허만박은 자신의 삶 대부분을 아름다운 고향의 산수에서 은둔하 며 조용하게 보냈지만, 당시 나라의 형세가 혼란하고 위급했던 만큼 그에 대한 심정과 감성도 시의 소재나 때에 따라 드러내기도 하였다. 1910년을 전후해 지은 시에서는 나라 잃은 분노와 비통함의 시적 정서 가 점점 고조되고 있었으며, 더불어 체념과 자조적 한탄도 뒤섞여 표출 되었다. 또 현실과 차단한 채 은거의 즐거움만으로 스스로를 위로하는 의식도 담아내었음을 확인할 수 있었다.

RC bridge deck replacement will be taking more than half of budget in intensive renovation program of road investment in Japan. Prolong life-time measures such as improvement of the materials and effective repair methods to sustain a long life span are thus studying rigorously. Those countermeasures are implemented when the damage or deterioration becomes remarkable as to be observed by naked eyes, and therefore these activities can be regarded as a corrective maintenance activity, contrary to proactive maintenance. As for the proactive maintenance overall health evaluation for the infrastructures even in the early damage/ deterioration stage would be vital. Acoustic emission is an elastic wave generated due to cracks occurrence, growth and nucleation, and these AEs are referred to as primary AE activity while the emissions due to existent cracks’ reversible motion induced by internal stress distributions are referred to as secondary AE activity. In general the further deterioration proceeds, the more intensive AE activity are obtained. While as for the elastic wave velocities within the objective, smaller velocities imply more deteriorated condition than that of large velocities. Accordingly, it can be appeared that small velocity with remarkable AE occurrence could suggest serious deterioration condition; however careful examinations of AE activity in combination with wave velocity in seriously fatigue-damage RC deck questions this fact, e.g., serious damage areas, assumed both from elastic wave velocity and developed cracks on the surface, generates less emissions than of miner damage. This study details those findings with on-site AE monitoring and AE tomography results.

교배종 ‘농협 애’ 호박은 F₁ 교배종으로 수량성이 뛰어나 고, 과형이 H형으로 외관상 모양이 우수할 뿐만 아니라 잎이 작고 절간이 짧아 저온기 터넬 억제재배에 알맞은 품종이다. 모계 SA11은 과형이 H형으로 다소 통통하고 짧으면서 절간 길이가 짧아 절성이 좋은 계통으로 육성하였고, 부계 SJ23은 과장이 다소 길면서 육질이 단단한 계통으로 선발 육성하였 다. 1996년도에 조합작성 교배하여, 1997년도에 조합선발시 험과 시교채종을 하였고, 1998～1999년도에 주요 재배단지에 서 농가 실증시험을 실시하여 우수한 평가결과를 얻어 1999 년에 품종등록한 후 농가에 공급하기 시작하였다. ‘농협 애’ 호박 품종의 특징은 기존의 애호박 품종보다 마디 절성이 높 고 수량이 많은 다수확 품종으로 잎이 작고 절간이 짧으며, 초세가 적당하여 밀식재배가 가능하다. 특히 절간이 짧고 절 성이 좋기 때문에 장기재배시 덩굴내림을 해 주어야하는 노 동력을 줄일 수 있는 특성을 가지고 있다. 과형은 H자형으로 외관상 모양이 우수하고, 과피색은 연한 담녹색으로 상품성이 우수하다. 과육질은 단단한 편으로 수송성이 뛰어나고, 측지 발생이 잘 되므로 측지를 이용한 재배도 가능하다. 기존 품종 에 비해 수확량이 많은 다수확 품종으로 터넬 억제재배를 주 로 하는 전남, 경남, 충남지역에서 가장 인기 있는 품종으로 널리 재배되고 있다.

In this study, it was evaluated air content properties of concrete using air-entraining agents for modified flyash.