Recently, considerable attention has been given to nickel-based superalloys used in additive manufacturing. However, additive manufacturing is limited by a slow build rate in obtaining optimal densities. In this study, optimal volumetric energy density (VED) was calculated using optimal process parameters of IN718 provided by additive manufacturing of laser powder-bed fusion. The laser power and scan speed were controlled using the same ratio to maintain the optimal VED and achieve a fast build rate. Cube samples were manufactured using seven process parameters, including an optimal process parameter. Analysis was conducted based on changes in density and melt-pool morphology. At a low laser power and scan speed, the energy applied to the powder bed was proportional to and not . At a high laser power and scan speed, a curved track was formed due to Plateau-Rayleigh instability. However, a wide melt-pool shape and continuous track were formed, which did not significantly affect the density. We were able to verify the validity of the VED formula and succeeded in achieving a 75% higher build rate than that of the optimal parameter, with a slight decrease in density and hardness.

Ni–Cr–Al metal-foam-supported catalysts for steam methane reforming (SMR) are manufactured by applying a catalytic Ni/Al2O3 sol–gel coating to powder alloyed metallic foam. The structure, microstructure, mechanical stability, and hydrogen yield efficiency of the obtained catalysts are evaluated. The structural and microstructural characteristics show that the catalyst is well coated on the open-pore Ni–Cr–Al foam without cracks or spallation. The measured compressive yield strengths are 2–3 MPa at room temperature and 1.5–2.2 MPa at 750oC regardless of sample size. The specimens exhibit a weight loss of up to 9–10% at elevated temperature owing to the spallation of the Ni/Al2O3 catalyst. However, the metal-foam-supported catalyst appears to have higher mechanical stability than ceramic pellet catalysts. In SMR simulations tests, a methane conversion ratio of up to 96% is obtained with a high hydrogen yield efficiency of 82%.

In this study, the high-temperature oxidation properties of austenitic 316L stainless steel manufactured by laser powder bed fusion (LPBF) is investigated and compared with conventional 316L manufactured by hot rolling (HR). The initial microstructure of LPBF-SS316L exhibits a molten pool ~100 μm in size and grains grown along the building direction. Isotropic grains (~35 μm) are detected in the HR-SS316L. In high-temperature oxidation tests performed at 700oC and 900oC, LPBF-SS316L demonstrates slightly superior high-temperature oxidation resistance compared to HR-SS316L. After the initial oxidation at 700oC, shown as an increase in weight, almost no further oxidation is observed for both materials. At 900oC, the oxidation weight displays a parabolic trend and both materials exhibit similar behavior. However, at 1100oC, LPBF-SS316L oxidizes in a parabolic manner, but HR-SS316L shows a breakaway oxidation behavior. The oxide layers of LPBF-SS316L and HR-SS316L are mainly composed of Cr2O3, Febased oxides, and spinel phases. In LPBF-SS316L, a uniform Cr depletion region is observed, whereas a Cr depletion region appears at the grain boundary in HR-SS316L. It is evident from the results that the microstructure and the hightemperature oxidation characteristics and behavior are related.

The Fe-22wt.%Cr-6wt.%Al foams were fabricated via the powder alloying process in this study. The structural characteristics, microstructure, and mechanical properties of Fe-Cr-Al foams with different average pore sizes were investigated. Result of the structural analysis shows that the average pore sizes were measured as 474 μm (450 foam) and 1220 μm (1200 foam). Regardless of the pore size, Fe-Cr-Al foams had a Weaire-Phelan bubble structure, and α-ferrite was the major constituent phase. Tensile and compressive tests were conducted with an initial strain rate of 10−3 /s. Tensile yield strengths were 3.4 MPa (450 foam) and 1.4 MPa (1200 foam). Note that the total elongation of 1200 foam was higher than that of 450 foam. Furthermore, their compressive yield strengths were 2.5 MPa (450 foam) and 1.1 MPa (1200 foam), respectively. Different compressive deformation behaviors according to the pore sizes of the Fe-Cr-Al foams were characterized: strain hardening for the 450 foam and constant flow stress after a slight stress drop for the 1200 foam. The effect of structural characteristics on the mechanical properties was also discussed.

The prediction of Jominy hardness curves and the effect of alloying elements on the hardenability of boron steels (19 different steels) are investigated using multiple regression analysis. To evaluate the hardenability of boron steels, Jominy end quenching tests are performed. Regardless of the alloy type, lath martensite structure is observed at the quenching end, and ferrite and pearlite structures are detected in the core. Some bainite microstructure also appears in areas where hardness is sharply reduced. Through multiple regression analysis method, the average multiplying factor (regression coefficient) for each alloying element is derived. As a result, B is found to be 6308.6, C is 71.5, Si is 59.4, Mn is 25.5, Ti is 13.8, and Cr is 24.5. The valid concentration ranges of the main alloying elements are 19 ppm < B < 28 ppm, 0.17 < C < 0.27 wt%, 0.19 < Si < 0.30 wt%, 0.75 < Mn < 1.15 wt%, 0.15 < Cr < 0.82 wt%, and 3 < N < 7 ppm. It is possible to predict changes of hardenability and hardness curves based on the above method. In the validation results of the multiple regression analysis, it is confirmed that the measured hardness values are within the error range of the predicted curves, regardless of alloy type.

Traumatic eosinophilic granuloma(TEG) of the oral mucosa is considered to be a reactive benign condition. Histology revealed diffuse mixed infiltration of eosinophil and atypical mononuclear cells. We have described an additional case of TEG simulating oral malignany where immunohistochemistry revealed the presence of CD30+ large atypical cells. The CD30+ lymphoproliferative disorder(LPD) of oral mucosa, although rare, has also been described. In this case, there was scattered distribution of CD30+ cells. After the incisional biopsy, the remainder of oral lesion got disappeared progressively and there is no sign of recurrence. We believe that this case could be a reactive rather than neoplastic process, and it has been suggested that a subset of TEG could be included within the spectrum of CD30+ LPDs. Therefore, oral surgeon and pathologists’ awareness of this condition will reduce the likelihood of misdiagnosis and inappropriate aggressive treatment for this benign, self-limiting lesion.

Indirubin is the active ingredient 0 1' a traditional Chinese herbal medicine, Danggui Longhui Wan, used for the t reatment of chronic myelocytic leu kelma The author reports that novel indirubin derivative, 5'-nitro-indirubinox ime (5'-NIO) , has potent a nti -proliferative activity on human o1'al cancer cells , Treatment of KB cells with 5’ NIO s howed a s t rong cell growth inhibit ion during indicated time point , A typical apoptosis pattern was obtained with DNA fragmenta tion and i mmunofl uorescence analysis of annelxn-v-f!ous Western blot data revealed that p53 and p21CIP1/Waf- l level increased strongJy upon 5'-NIO treatment , The a uthor next tested whether 5'-NIO could activate apoptos is related proteins s uch as caspase-3/-7/-9, [n cells exposed to 5‘-NIO, activation of caspase-3 and -7 was observed, Interesti ngly‘ caspase-9 and cytochrome c cou ld s li ghtly activate in response to 5’-NIO. These results indicate that 5’-NIO strongly induces oral cancer cells apoptosis via a Mi tochondria-mediated cas pase cascade pathway, These observations together s uggest that 5’ NTO may have a possible therapeutic potentia[ to oral cancer

Polo-Like Kinase(PLK) is a cell cycle-regulated, cyclin-independent serine/threonine protein kinase. Recent reports have shown a critical role for PLK during tumorigenesis. To explore whether PLK plays a general role as a tumor marker of oral squamous cell carcinomas, we examined the expression of PLK mRNA and protein in oral squamous cell carcinoma cells and immortalized normal oral keratinocytes(INOK). We also investigated that PLK mRNA was expressed in specimens from 4NQO-induced SD rat tongue carcinomas using in situ RT-PCR methods. Immunocytochemically, most of the PLK was highly expressed in the nucleus of carcinoma cells, but not INOK. RT-PCR revealed PLK1 mRNA was detected in the FaDu and Hep2 cancer cells, but no detected in the INOK. In situ RT-PCR revealed PLK1 mRNA expression increased sequentially from hyperplasia to dysplasia, and squamous cell carcinoma during the malignant progression. PLK1 expression could reflect the degree of malignancy and proliferation in oral squamous cell carcinomas. Thus, in addition to being of diagnostic value, modulation of PLK1 activity in the tumors by chemotherapeutic agents or gene therapy may prove to be of therapeutic value.

해송×소나무 인공교배 차대들의 침엽 및 생장특성을 조사하였다. 해송×소나무 교잡종 3, 5, 8년생 수고생장은 조합간에 많은 차이가 있었다. 해송(충남 4)×소나무(강원 29) 조합 3, 5, 8년생의 수고생장이 110, 172, 234cm로 전 조합 평균보다 8%, 9%, 11% 우수하였으며, 교배 모수인 해송 수형목 충남4호와 화분수인 소나무 수형목 경북 5호 보다도 각각 46%, 61% 우수한 생장을 하여 잡종강세 현상으로 생각된다. 해송×소나무 침엽의 수지구지수는 0.71~0.89로서 교배모수인 해송을 더 많이 닮았다.

우리나라의 대표적 향토수종인 소나무 침엽의 지리적 변이를 알아보기 위하여 남한 전 지역을 대상으로 위도와 경도를 30' 간격으로 교차되는 35집단을 선정하고 침엽을 채취하여 형태적 특성을 조사하였다. 침엽길이, 침엽폭, 기공열수, 기공밀도, 거치수, 수지구수가 집단간, 개체간에 많은 차이가 있었으며, 개체간의 차이가 집단간의 차이보다 더 컸다. 기공밀도는 남부지역의 집단들 보다는 북부지역의 집단들이 더 높았으며, 표고가 낮은 지역의 집단들 보다는 표고가 높은 지역의 집단들이 기공밀도가 더 높았다. 거치수는 북부지역의 집단들보다는 남부지역의 집단들이 더 많았으며, 표고가 높은지역의 집단들보다는 표고가 낮은 지역의 집단들이 더 많았다. 수지구 수는 해안에서 거리가 먼 내륙의 집단들 보다는 해안에서 거리가 가까운 집단들이 더 많았다. 그리고 수지구 지수는 동부지역의 집단들 보다는 서부지역의 집단들이 더 높았다. 침엽의 형태적 특성으로 유집분석 결과 3개 군으로 구분되었으며 제III군은 I, II군에 비하여 거치수는 적고, 기공 밀도가 높은 태백산맥 주위의 집단들이었다.

한국 자생 개맨드라미를 초장생장을 억제시켜서 분화식물로서의 이용 가능성을 검토하기위하여 적심 및 왜화제처리에 따라서 생장 및 개화에 미치는 영향을 조사하였다. 적심의 횟수가 1회부터 3회까지 증가할수록 초장, 절간장 및 화서장은 월등히 작아지고 화서의 수, 엽수 및 측지수는 증가하였다. Diniconazole 12.5-50.0mg·L-1, hexaconazole 10.0-40.0mg·L-1 및 daminozide 3,400-13,600mg·L-1의 처리는 개맨드라미의 초장, 절간장 및 엽장 등의 생장을 감소시켰고 화서의 수 및 잎의 수는 증가되었다. 특히 diniconazole 50mg·L-1 및 daminozide 6,800mg·L-1 처리는 대조구의 초장이 81.3cm에 비교하여 50cm 이하로 월등히 작았고 화서의 수는 2.7개로 대조구 1개보다는 월등히 많았다. 한편 hexaconazole과 daminozide는 농도 및 처리횟수가 증가할 수록 초장이 감소하는 경향이었으나 diniconazole은 차이가 없었다. 따라서 개맨드라미를 왜화시키기 위해서는 12cm 정도 자란, 생육 초기에 diniconazole 50mg·L-1 및 daminozide 6,800mg·L-1를 1회 경엽에 살포하거나 2~3회 정도 적심해주는 것이 바람직하다.

다양한 광환경에 대한 음나무 유묘의 생장특성과 엽록소 함량, 파장별 흡광도, 광합성 속도 등 광합성 특성을 조사하였다. 엽면적, 엽병길이 , RGR은 낮은 광조건에서 생장시킨 개체에서 크게 나타났고, SLW는 강한 광조건에서 각각 생장한 개체에서 높았다. 엽록소 함량은 염록소 a, 엽록소 b, 엽록소 a+b 함량 등은 낮은 광조건에서 생장시킨 개체에서 높았고, 엽록소 a/b 율은 강한 광조건에서 각각 생장한 개체에서 높았다. 광합성 유효파장역에서 평균 흡광값은 음엽이 0.75로 양엽의 0.70보다 높았다. 광합성 속도는 강한 광조건에서 생장한 개체가 높은 광합성 속도를 나타내었다. 광포화점은 전광조건 하에서 생육시킨 유묘에서 700 μmol·m-2·s-1, 임내광 조건에서 생육시킨 조건에서 300 μmol·m-2·s-1이었고, 생장상의 강광조건에서는 500 μmol·m-2·s-1, 약광조건에서는 300 μmol·m-2·s-1이었다.

음나무는 잎을 산채로, 뿌리와 수피를 식의약용으로 다양하게 이용되고 있으며, 최근 농산촌의 신소득 작목으로 재배하기 시작하였다. 본 연구는 엽내 무기성분분석을 통하여 음나무 유묘의 생장에 미치는 영향을 조사하여 향후 재배 및 생산성 향상을 위한 기초자료를 제공하고자 수행하였다. 음나무 유묘의 엽내 무기영양원소는 다량 및 미량 무기성분에 따라 함량차이를 보였으며, N성분이 가장 많았으며, 다음으로 K, Ca, P, Mg, Mn, Fe, Zn 순으로 나타났다. N, P, K 성분은 유묘의 생장과 고도의 정의 상관관계를 나타내었으며, Mg와 Mn은 낮은 정의 상관을 보인 반면, Na과는 높은 부의 상관관계를 나타내었다. 한편 Ca, Fe, Cu, Zn 성분은 유묘의 생장과 상관관계가 인정되지 않았다. 분석된 무기성분 중에서 N, P, K, Mg, Mn, Na 성분은 음나무 유묘의 생장에 영향을 미치는 (P<0.01) 무기성분으로 나타났으며, 특히 N성분은 가장 영향을 미치는 성분으로 나타났다.

An inverse fluidized-bed biofilm reactor (IFBBR) was used for the treatment of highly-emulsified oily wastewater. When the concentration of biomass which was cultivated in the synthetic wastewater reached to 6000㎎/L, the oily wastewater was employed to the reactor with a input COD concentration range of 50㎎/L to 1900㎎/L. Virtually the IFBBR showed a high stability during the long operation period although some fluctuation was observed. The COD removal efficiency was maintained over 90% under the condition that organic loading rate should be controlled under the value of 1.5 ㎏COD/㎥/day, and F/M ratio is 1.0㎏COD/㎏VSS/day at 22℃ and HRT of 12 hrs. As increasing organic loading rates, the biomass concentration was decreased steadily with decreasing of biofilm dry density rather than biofilm thickness. Based on the experimental results, It was suggested that the decrease in biofilm dry density was caused by a loss of biomass inside the biofilm.