The detailed understanding of fluorescence emission processes is still unclear. This study demonstrates Aegle marmelos derived luminescent heteroatoms (N, Ca, K) doped carbon quantum dots (CQDs) using an economically and ecologically sustainable synthesis process without the necessity for any doping precursors due to its phytochemical, vitamin and mineral content. Carboxyl functionalization was done by adding lemon juice to the fruit extract. The morphological, physiochemical, compositional, crystallinity, and surface functional groups having heteroatom doped CQDs were analysed by HRTEM, EDX, XPS, XRD, FTIR etc. Besides, CQDs exhibited pH and solvent-dependent tuneable fluorescence characteristics. In fact, beyond pH 7.77, a protonation-deprotonation-driven red-shift was observed together with a decrease in the contribution of prominent peaks. Meanwhile, the features of solvatochromic fluorescence were examined in a range of aprotic and protic solvents with low and high polarity. Based on the studied Kamlet–Taft parameters and the obtained spectroscopic characterizations, a suitable fluorescence emission mechanism is provided. The observed solvatochromic fluorescence is thought to be caused by a combination of dipole moment polarisation, intramolecular charge transfer processes with or without H-bond stabilisation via the interaction of heteroatoms doped CQDs with solvent mediated by electron donation and acceptance from various surface functional groups such as hydroxyl, carboxyl with solvent molecules. Hence, this study is believed to promote the development of eco-tuneable fluorescent heteroatom doped CQDs and provide further insights into the fundamental fluorescence mechanisms, which include the relationship between morphology, surface properties and plausible quantum effects between CQDs and solvents.

Depending on the type of waste, DC plasma torch uses a transfer type operation for conductive waste and a non-transfer type operation for non-conductive waste. The transfer mode plasma torch can secure high throughput because the arc directly contacts the object and has high thermal efficiency. However, since the non-transfer mode does not have a higher thermal efficiency than the transfer mode, higher output is required to secure high throughput. A method of increasing the output of the plasma torch is increasing the current or extending the length of the plasma arc. However, the method of increasing the current affects the life of the electrode, and there is a limit to extending the arc length in the positive polarity plasma torch. Therefore, it is effective to design the plasma torch with reverse polarity to secure life and extend the arc length. In the reverse polarity plasma torch, the front electrode serves as the cathode, and the cathode point is not easy to control compared to the anode point, which may cause abnormal arcing and damage the plasma torch. This paper was conducted to investigate the conditions for securing the safety of these non-transferable reverse polarity plasma torch. The plasma torch is designed to have an output of 100 kW or less and to use the detachable nozzle to control the cathode point. The test showed that the shape of the nozzle prevented the cathode point moving outside of plasma torch and the excessive extension of the arc. Thanks to this, it was confirmed that plasma could be stably formed and abnormal arcing could also be prevented.

DC plasma torch is reported as a technology that can be treated regardless of waste types because it can select transfer or non-transfer operation modes depending on the electrical conductivity of waste. Thanks to this characteristic, countries that operate nuclear power plants such as Switzerland, Japan, and Taiwan have developed high-power DC plasma torch to dispose of radioactive waste. And also in korea, a plasma torch is being developed to dispose of radioactive waste. This study was conducted to investigate the characteristics of the reverse polarity plasma torch according to the conditions of interelectrodes. The inter-electrodes of plasma torch used in the study was designed to be 25, 37 mm in diameter and 180 to 400 mm in length. As a result of the test, it was confirmed that the smaller the diameter and the longer the length of the inter-electrode, the more advantageous it was to achieve a high output power. And it was confirmed that the power torch would be 500 kW when the diameter of the inter-electrode was 25 mm, the length was 400 mm, and the current was 500 A.

미세먼지발생 문제는 커다란 사회적 문제로 대두되고 있다. 선박에서는 주 추진 동력원으로 디젤엔진을 주로 사용하고 있다. 본 연구에서는 디젤엔진에서 발생하는 미세먼지로 알려진 입자상 물질을 줄이기 위해서 디젤엔진의 후처리시스템으로 사용 중인 DPF(디 젤미립자 필터, Diesel particulate filter)를 소개하고자 한다. DPF의 소재로는 Cordierite와 SiC (Silicon carbide)의 두 가지가 사용되고 있다. 본 논문에서는 SiC DPF에 사용되는 접합제의 물성 향상을 위해서 기존 접합제로 사용된 SiC 계열의 물질 대신 코디얼라이트를 사용하여 열 팽창계수 변화를 통한 고온 변형에 대한 열 내구성을 평가하였으며, 접합제와 Segment 사이의 결합을 결정짓는 바탕제에 주성분인 실리카 졸의 pH 변화에 따른 물성 변화를 확인하였다. 이를 기반으로 실리카 졸의 반응성을 높이기 위해 Siline계 커플링제를 첨가하거나 SiC를 일부 첨가함으로써 접합제의 물성 변화의 영향에 대해서 실험을 통하여 확인하였다.

Carbonaceous materials have widely been used as sorbents. For advanced applications, fine-tuning porosity and polarity of carbonaceous materials is highly desired. Various control methods for porosity and polarity of carbonaceous materials are introduced and the designed carbonaceous materials are implemented for their intrinsic adsorption applications for various gas molecules (e.g., CO2, N2, H2), organic molecules, and metal ions.

에멀젼은 섞이지 않은 두 물질을 분산시스템으로 혼합시켜 놓은 것이다. 에멀젼의 점도에 영향을 미치는 인자는 유화입자 크기, 연속상 및 분산상 종류, 연속상과 분산상의 비, 유화제 종류 및 유화기기 등 다양한 요소들이 있다. 본 연구에서는 오일 극성도에 따라 에멀젼의 점도 변화를 관찰하였고 이를 유기개념도를 이용하여 해석하였다. 탄화수소계, 에스테르계 및 실리콘계 오일을 사용하여 에멀젼을 제조하여 점도를 측정하였다. 오일 극성도가 높을수록 계면에 위치하는 유화제 및 유화안정제의 양이 적어지기 때문에 점도는 감소하였다. 극성 오일간 극성도를 수치적으로 비교하기 위해 유기개념도 이용하였으며 유기개념도상의 해석과 에멀젼의 점도 측정 결과가 실리콘 오일을 제외하고는 모두 일치하였다.

Aluminum nitride(AlN) films were grown on the C-face and on the Si-face of (0001) silicon carbide(SiC) substrates using plasma-assisted molecular-beam epitaxy(PA-MBE). This study was focused on first-stage growth manipulation prior to the start of AlN growth. Al pre-exposure, N-plasma pre-exposure, and simultaneous exposure(Al and N-plasma) procedures were used in the investigation. In addition, substrate polarity and, first-stage growth manipulation strongly affected the growth and properties of the AlN films. Al pre-exposure on the C-face and on the Si-face of SiC substrates prior to initiation of the AlN growth resulted in the formation of hexagonal hillocks on the surface. However, crack formation was observed on the C-face of SiC substrates without Al pre-exposure. X-ray rocking-curve measurements revealed that the AlN epilayers grown on the Si-face of the SiC showed relatively lower tilt and twist mosaic than did the epilayers grown on the C-face of the SiC. The results from the investigations reported in this paper indicate that the growth conditions on the Si-face of the SiC without Al pre-exposure was highly preferred to obtain the overall high-quality AlN epilayers formed using PA-MBE.

As the demand for large-scale analysis of gene expres- sion using DNA arrays increases, the importance of the surface characterization of DNA arrays has emerged. We com- pared the efficiency of molecular biological applications on solid-phases with different surface polarities to identify the most optimal conditions. We employed thiol-gold reactions for DNA immobilization on solid surfaces. The surface polarity was controlled by creating a self-assembled monolayer (SAM) of mercaptohexanol or hepthanethiol, which create hydrop- hilic or hydrophobic surface properties, respectively. A hyd- rophilic environment was found to be much more favorable to solid-phase molecular biological manipulations. A SAM of mercaptoethanol had the highest affinity to DNA mole- cules in our experimetns and it showed greater efficiency in terms of DNA hybridization and polymerization. The opti- mal DNA concentration for immobilization was found to be 0.5 mM. The optimal reaction time for both thiolated DNA and matrix molecules was 10 min and for the polymerase reaction time was 150 min. Under these optimized condi- tions, molecular biology techniques including DNA hybri- dization, ligation, polymerization, PCR and multiplex PCR were shown to be feasible in solid-state conditions. We de-monstrated from our present analysis the importance of surface polarity in solid-phase molecular biological appli- cations. A hydrophilic SAM generated a far more favorable envi- ronment than hydrophobic SAM for solid‐state molecular techniques. Our findings suggest that the conditions and met- hods identified here could be used for DNA‐DNA hybri- dization applications such as DNA chips and for the further development of solid-phase genetic engineering applicatio- ns that involve DNA-enzyme interactions.

This paper reports a characteristic motion of a polarity inversion line (PIL) formed at the solar surface, which is newly found by performing a three-dimensional magnetohydrodynamic simulation of flux emergence in the Sun. A magnetic flux tube composed of twisted field lines is assumed to emerge below the surface, forming a bipolar region with a PIL at the surface. A key finding is the successive half-turn rotation of the PIL, leading to the formation of a quadrupolar-like region at the surface and a magnetic configuration in the corona; this configuration is reminiscent of, but essentially different from the so-called inverse-polarity configuration of a filament magnetic field. We discuss a physical mechanism for producing the half-turn rotation of a PIL, which gives new insights into the magnetic structure formed via flux emergence. This presents a reasonable explanation of the configuration of a filament magnetic field suggested by observations.

이 연구에서는 기상청에서 관측한 최근 7년(2002-2008)간의 낙뢰자료를 이용하여 남한지역에서 발생한 구름-지면 낙뢰 현상의 극성별 시 공간적 특성을 분석하였다. 낙뢰빈도는 극성에 관계없이 강한 경년변동, 계절변동 및 일 변동을 보이고 있다. 낙뢰빈도는 여름과 겨울에 각각 최대(74%) 및 최소(0.6%)를 보이고 있다. 또한 계절과 극성에 따라 다르지만 낙뢰는 평균적으로 새벽과 오후에 최대로 발생하는 일 변동을 보이고 있다. 정극성 비율(정극성/부극성)은 여름에 7.3%로 낮으나 겨울에는 62.5%로 강한 계절 변동을 보이고 있다. 낙뢰강도는 경년 및 일 변동은 거의 보이지 않고 있으며 낙뢰가 많이 발생하는 여름에 약하고 낙뢰가 적게 발생하는 겨울에 강한 계절 변동을 보이고 있다. 또한 정극성 낙뢰강도는 강한 계절 변동을 보이는 반면 부극성은 상대적으로 약한 계절 변동을 보이고 있다. 낙뢰밀도는 영동과 동해 지역보다 서부 내륙 및 서 남해상에서 높게 나타나고 있다. 낙뢰강도의 경우 극성에 관계없이 내륙에서보다 바다, 특히 동해상에서 강하게 나타나고 있다.

[n order to obtain the trlle expected DNA prod uct from PCR and RT-PCR using genornic DNA or cDNA reversely transcribed from mRNA. the PCR should be done in an appropriated condition. Sometimes the PCR was repeatedly fail ed. and cventllally the PCR product was turned out to be nonspecific and rudimentary . And more‘ t he PCR prodllctwas not reproducible even though careflll repeat of experiments. As the PCR was based on the exact primel hybridization. the condition of primer hybridization should be properly controlled by a nnealing temperatllre. But the selection of primer seqllences for targeting a specific gene is mostly important. A new method of primer eval uation is now available llsing DNA base pair polarity program. This study presents an example of PCR targeting to human Bax gene using genomic DNA. The DNA base pair polarity theory can di vide the genetic cord into propel DNA segments and calclllaLe their DNA base pair hybridization energy. Thus. mathematically the degree 0(' exact primer hybridization can be expected for the t r1l8 targeting of PCR. However, the DNA base pair polal'ityanalysis demonstrates that the more frequent number of DNA segment incl'eased the specificity of PCR. but decreased its sensitivity . While the greater polarity of DNA segment composed of increased nllmber of polarized DNA base pairs showed increased sensitivi ty 0 1' PCR. bllt relati vely decreased specificity of PCR. With the mllltiple analysis of PCR. especially for PCR cloning from the gDNA and cDNA, we found that the primers themselves showed secondary strllcture of partial hybridization between sameprimers or each pair primers. The DNA base pail‘ polarity signal can directly demonstrated symmetric sequences 0 1' each primer. and also can distinguish the dimmer formation from each pair primers. At least the symmetric seqllence of fOlll‘ base pairs dramatically showed the dimrner formation. On the other hand. in addi tion Lo the statlls of DNA base pair polarity the three-dimensional strllctllre of DNA dOllble helix targeted by the primer seqllences may affect the sensitivity and specificity of PCR detection. The present study introduced a new method of primer evalllation and selection in order to obtain abundant and exacL! y-trlle DNA product for genomic ffilltation analysis and gene expression profï le

이 연구에서는 강교량과 같은 토목 구조물에서 유도파의(Guided waves)한 종류인 램파(Lamb wave)를 이용하여 실시간으로 균열손상을 감지할 수 있는 새로운 비파괴 검사방법을 제안한다. 기존의 유도파를 이용한 기술들은, 손상을 감지하기 위해 비손상 상태의 자료를 저장하고 이를 새로이 얻어진 결과와 비교하는 방법을 사용함으로써 잠재적인 손상을 진단해 왔다. 그러나, 공용중인 강구조물은 다양한 하중 뿐 아니라 상시로 변화하는 자연환경에 노출되어 있기 때문에 동일한 비손상 상태의 응답을 얻는 것이 매우 어려우며 이러한 방법을 적용할 경우 오보(false alarm)의 우려도 매우 높다고 할 수 있다. 따라서 이 연구에서는 보다 안정적인 손상감지기법을 개발하기 위해 기존에 얻어진 초기치를 이용하지 않으면서 실시간으로 손상 여부를 판단할 수 있는 방법을 제안하고자 한다. 이 연구에서 제안된 감지 기술은, 압전소자의 극성과 판파의 특성을 이용하는 것으로 얇은 판의 양면에 부착된 압전소자를 통하여 균열손상에 의한 신호를 선택적으로 감지해 내는 데에 그 목적이 있다. 균열이 발생한 판에서 진행하는 판파는 균열로 인한 판의 두께변화로 인해 모드 변화를 일으키게 되는데, 제안된 감지기법으로 이러한 모드 변화만을 선택적으로 추출할 수 있다. 다양한 수치해석과 실험을 통해 이 연구에서 제안된 손상감지기법의 효율성과 적용성을 입증한다.

The influence of the polarity of the spreading solvent on the properties of the monolayer of poly(styrene-co-acrylonitrile)'s with various acrylonitrile contents was studied. The surface pressure - area isotherm and the apparent dipole moment - area isotherm were obtained and analyzed when the mixtures of methylene chloride and N-N-dimethylformamide used as spreading solvent. The isotherms were strongly influenced by the polarity of the solvent.

Observing some asymmetries in cross-clausal negative polarity licensing in Korean, Lee (2017) proposes that, under the SVO word order hypothesis (Kayne 1994), negative polarity items (NPIs) are licensed at the “Spec domain” of a negated predicate, rather than being regulated by the clause mate condition (CMC, Choe 1988, Lee 1994, Sohn 1995, Kim 1995, Chung 2006, a.o.). This paper argues, however, that Lee’s Spec domain approach faces some non-trivial difficulties and that a CMC-based theory like Sohn’s (1995) in terms of NPI movement to Spec of NegP more appropriately accommodates the cross-clausal NPI licensing facts.