• 한국축산식품학회지
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• 제38권2호
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• pp.362-375
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• 2018

This study proposed a rapid microscopic examination method for pork freshness evaluation by using the self-assembled hyperspectral microscopic imaging (HMI) system with the help of feature extraction algorithm and pattern recognition methods. Pork samples were stored for different days ranging from 0 to 5 days and the freshness of samples was divided into three levels which were determined by total volatile basic nitrogen (TVB-N) content. Meanwhile, hyperspectral microscopic images of samples were acquired by HMI system and processed by the following steps for the further analysis. Firstly, characteristic hyperspectral microscopic images were extracted by using principal component analysis (PCA) and then texture features were selected based on the gray level co-occurrence matrix (GLCM). Next, features data were reduced dimensionality by fisher discriminant analysis (FDA) for further building classification model. Finally, compared with linear discriminant analysis (LDA) model and support vector machine (SVM) model, good back propagation artificial neural network (BP-ANN) model obtained the best freshness classification with a 100 % accuracy rating based on the extracted data. The results confirm that the fabricated HMI system combined with multivariate algorithms has ability to evaluate the fresh degree of pork accurately in the microscopic level, which plays an important role in animal food quality control.

• 한국재료학회지
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• 제14권9호
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• pp.676-681
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• 2004

In-situ observation in SBM on the microfracture behavior of coating layer was performed for GA steel sheets that have various Fe contents and thickness of coating layer. In case of cross sectional side of coating layer that was in a tensile stress state during bending, fine perpendicular crack pre-induced during galvannealing grew and propagated rapidly toward the coating surface with the increase of strain. And then it grew and propagated along the ${\Gamma}/Fe$ matrix interface, and combined with the nearest another perpendicular crack. Consequently, flaking occurred. The more Fe content and thickness of coating layer increased, the more average crack interval and flaking resistivity increased. Exfoliation was little observed at coating surface in a tensile stress state.

• 자원환경지질
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• 제17권1호
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• pp.35-47
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• 1984

Combined mineralogical and geochemical studies were made on two hundred eighty one representative samples from uraniferous coaly meta-pelites of the Ogcheon metamorphic terrain. Different mineral occurrence of the areas investigated should be taken into account for chemical processes for uranium extraction. Secondary uranium minerals identified are metauranocircite, metatorbernite and autunite. These are disseminated mostly on the laumontites which infused and filled secondary openings in the coaly matrix, and are often closely associated with iron oxides. The uranium distribution show distinctly log normal. Geochemical correlation coefficient of uranium and organic carbon displays +0.624~+0.796. The relationship of the major components to uranium can be expressed by the following regression equation: Log $(U_3O_8{\times}10^4)$=1.40117-0.00076 (quartz) -0.00118 (muscovite) +0.00235 (biotite) +0.00323 (other silicates) - 0.01114 (apatite) +0.01124 (hematite) +0.00149 (limonite) -0.01823 (opaques)+0.03049 (organic carbon). Uranium in the coaly meta-pelites of the Ogcheon Group was deposited together under same physico-chemical environmental conditions. There is a considerable variation in the ${\delta}^{34}S$ values (11.2~16.8 per mil) of the pyrites from the U-bearing meta-pelites, which implies sedimentary origin. The two U-bearing coaly rocks analyzed have ${\delta}^{13}C$ values between -16.88~-18.00 per mil, which suggests organic.

• 분석과학
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• 제30권2호
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• pp.102-111
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• 2017

Here we reported a methodology for identification of triacylglycerols (TAGs) and diacylglycerols (DAGs) in coix seed by preparative thin layer chromatography (prep-TLC) and non-aqueous reversed-phase liquid chromatography (NARP LC)-atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (MS/MS). Lipid components were extracted from coix seed by reflux extraction using n-hexane for 3 hr. TAGs and DAGs in coix seed extract were effectively purified and isolated from matrix interferences by prep-TLC and then analyzed by LC-APCI-MS and MS/MS for identification. TAGs were effectively identified taking into consideration of their LC retention behavior, APCI-MS spectra patterns, and MS/MS spectra of $[DAG]^+$ ions. In MS/MS spectra of TAGs, diacylglycerol-like fragment $[DAG]^+$ ions were useful to identify TAGs with isobaric fragment ions. Based on an established method, 27 TAGs and 8 DAGs were identified in coix seed extract. Among them, 15 TAGs and 8 DAGs were for the first time observed in coix seed. Interestingly, some of TAGs isolated by prep-TLC were partly converted into DAGs through probably photolysis process during storing in room temperature. Thus, degradation phenomenon of TAGs should be considered in the quality evaluation and nutritional property of coix seed. LC-APCI-MS/MS combined with prep-TLC will be practical method for precise TAG and DAG analysis of other herbal plants.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권1호
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• pp.321-340
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• 2016

The Compressive Video Sensing (CVS) is a useful technology for wireless systems requiring simple encoders but handling more complex decoders, and its rate-distortion performance is highly affected by the quantization of measurements and reconstruction of video frame, which motivates us to presents the Space-Time Quantization (ST-Q) and Motion-Aligned Reconstruction (MA-R) in this paper to both improve the performance of CVS system. The ST-Q removes the space-time redundancy in the measurement vector to reduce the amount of bits required to encode the video frame, and it also guarantees a low quantization error due to the fact that the high frequency of small values close to zero in the predictive residuals limits the intensity of quantizing noise. The MA-R constructs the Multi-Hypothesis (MH) matrix by selecting the temporal neighbors along the motion trajectory of current to-be-reconstructed block to improve the accuracy of prediction, and besides it reduces the computational complexity of motion estimation by the extraction of static area and 3-D Recursive Search (3DRS). Extensive experiments validate that the significant improvements is achieved by ST-Q in the rate-distortion as compared with the existing quantization methods, and the MA-R improves both the objective and the subjective quality of the reconstructed video frame. Combined with ST-Q and MA-R, the CVS system obtains a significant rate-distortion performance gain when compared with the existing CS-based video codecs.

• 한국미생물·생명공학회지
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• 제17권1호
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• pp.74-80
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• 1989

광합성 세균의 수소생성 향상을 위한 노력의 일환으로 수소생성능이 좋은 Rhodopseudomonas E15-1 을 고정화하여 수소생성에 적당한 조건을 조사하였다. 담체로 4%의 alginate를 사용하였을 때 수소생성량이 많았으며 고정화함에 따라 산소. 질소에 대한 억제효과를 덜 받았다. Alginate 고정화 세포는 그 지름을 2mm 이하로 하는 것이 겔내로의 확산저항이 적으므로 적당했다. 여러가지 유기물을 활용하여 수소를 생성할 수 있었으며 특히 citrate, fumarate와 malate 같은 유기산의 경우 30mM의 농도가 수소생성에 있어서 적당하였다. 또한 고정화세포를 이용한 계속적인 수소생성에 있어서 20일부터 활성이 감소하기는 하나 겔의 구조적 안정성은 30일까지 유지되었다.

• 한국항해항만학회지
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• 제32권8호
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• pp.653-658
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• 2008

국제물류환경변화에 따라 국제복합운송의 수요가 지속적으로 증가하고 있는 상황에서 해공복합운송의 중요성은 더욱 높아지고, 적극적인 시장개발 등의 노력에 의해 추가적인 물량 확보가 충분히 가능하다. 본 연구의 목적은 복합운송의 국제유통경로분석과 포트폴리오분석을 통해 해공복합운송 화물유치를 위한 정책대안을 제시하는 것이다. 유통경로분석과 포트폴리오 분석결과, 우리나라 전체 해공복합운송 물동량의 88.1%를 차지하고 있는 Qingdao, Shanghai, Weihai, Yantai지역을 중심으로 구체적인 화물유치전략이 필요한 것으로 나타났다. 이를 제외한 지역들은 물동량이 매우 적고, 상대적으로 변동성이 매우 큰 것으로 분석되었다. 특히, Vladivostok, Dandong, Tianjinxingang은 지속적으로 물동량이 감소하여 성장률과 시장점유율이 낮아지고 있어, 이들 지역에 대해서는 공격적인 화물유치전략보다는 안정적인 화물유지전략이 필요할 것이다.

• Corrosion Science and Technology
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• 제8권3호
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• pp.110-115
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• 2009

At the onset of corrosion of steel in concrete, hydrogen ions usually evolve in the process of electrochemical reaction, thereby decreasing the pH of the pore solution, which can be buffered by cement hydration products, as being representatively illustrated by calcium hydroxide. Hence, a fall in the pH is dependent on properties of cement hydration (i.e. hydration products and degree of hydration). The present study tested acid neutralization capacity (ANC) of cementitious binders of OPC(Ordinary Portland Cement), 30% PFA(Pulverized Fuel Ash), 60% GGBS(Ground Granulated Blast Furnace Slag), 10% SF(Silica Fume) to quantify the resistance of cement matrix to a pH fall. Cement pastes were cast at 0.4 of a free W/C ratio with 1.5% chlorides by weight of binder in cast. Powder samples obtained crushed and ground specimen after 200 days of curing were diluted in still water combined with different levels of 1M nitric acid solution, ranging from 0.5 to 20 mol/kg. Then, the pH of diluted solution was monitored until any further change in the pH did not take place. It was seen that the pH of the diluted solution gradually decreased as the molar amount of nitric acid increased. At some particular values of the pH, however, a decrease in the pH was marginal, which can be expressed in the peak resistances to a pH fall in the ANC curve. The peaks occurred at the variations in the pH, depending on binder type, but commonly at about 12.5 in the pH, indicate a resistance of precipitated calcium hydroxide. The measurement of water soluble chloride at the end of test showed that the amount of free chloride was significantly increased at the pH corresponding to the peaks in the ANC curve, which may reflect the adsorption of hydration products to chlorides.

• 한국지반공학회논문집
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• 제29권8호
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• pp.65-73
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• 2013

지중 열교환 시스템은 지속적인 에너지 효율의 개선으로 공간 냉난방을 위한 친환경적 에너지 기술로 주목받고 있다. 지중에 매설된 파이프는 내부 유체 순환을 통하여 인접한 지반과 열적 상호작용으로부터 직접적인 열에너지 교환을 수행한다. 하지만, 파이프의 수치모델링에서 열-수리가 연관된 난류해석과 파이프의 긴 세장비에 의한 메쉬사이즈의 부적합성은 열교환 시스템의 적절한 수치해석을 어렵게 하고 있다. 본 논문에서는 파이프 내부 유체흐름에 대한 에너지 보존의 법칙을 적용하여 지배방정식을 유도하였으며, Galerkin수식화와 시간적분을 통하여 열-수리 연동일차원 파이프 요소를 개발하였다. 그리고 제안된 파이프 요소를 기 개발된 다공질 재료를 위한 열-수리-역학(Thermo-Hydro-Mechanical) 해석을 위한 유한요소 프로그램과 결합하였다. 개발된 요소를 이용한 수치해석 결과는 열응답 시험(Thermal Response Test) 결과로부터 주위지반의 유효 열전도도를 평가하기 위하여 사용하는 선형 열원 모델이 인접 파이프간의 열적상호작용과 파이프의 단부효과에 의하여 지반의 열전도도를 과다 평가하는 것으로 보여주었다. 따라서 열응답 시험 해석 결과에 대한 역해석을 적용하여 최적의 수렴성을 보여주는 변환행렬을 제시하였다.

• Korean Chemical Engineering Research
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• 제47권4호
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• pp.436-440
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• 2009

본 연구에서는 초산화칼륨이 포함된 화학 폐를 이용하여 이산화탄소를 산소로 전환시켰다. 우선 초산화칼륨을 수산화칼슘과 혼합하여 초산화칼륨의 반응성을 낮추었다. 기제조한 수산화칼슘-초산화칼륨 혼합물을 수분제거에 용이한 실리콘 고분자 매트릭스에 여러 가지 비율로 분산시켜 화학 폐를 제조하였다. 일반적으로 화학 폐에 있는 초산화칼륨의 양이 많아질수록 변환되는 이산화탄소와 발생되는 산소의 양이 증가하였다. 후리에 적외선 분광기 분석결과 화학 폐에 분산되어 있는 규소-산소의 단일결합이 $1,050cm^{-1}$에서 나타났다. 규소-산소 단일결합의 흡수도는 화학 폐에 있는 규소고분자의 함량이 높을수록 높았다. 본 실험결과는 이산화황이나 이산화질소같은 산성 가스의 전환에도 이용될 수 있음을 보여준다.