The aggressive scaling of dynamic random-access memory capacitors has increased the need to maintain high capacitance despite the limited physical thickness of electrodes and dielectrics. This makes it essential to use high-k dielectric materials. TiO2 has a large dielectric constant, ranging from 30~75 in the anatase phase to 90~170 in rutile phase. However, it has significant leakage current due to low energy barriers for electron conduction, which is a critical drawback. Suppressing the leakage current while scaling to achieve an equivalent oxide thickness (EOT) below 0.5 nm is necessary to control the influence of interlayers on capacitor performance. For this, Pt and Ru, with their high work function, can be used instead of a conventional TiN substrate to increase the Schottky barrier height. Additionally, forming rutile-TiO2 on RuO2 with excellent lattice compatibility by epitaxial growth can minimize leakage current. Furthermore, plasma-enhanced atomic layer deposition (PEALD) can be used to deposit a uniform thin film with high density and low defects at low temperatures, to reduce the impact of interfacial reactions on electrical properties at high temperatures. In this study, TiO2 was deposited using PEALD, using substrates of Pt and Ru treated with rapid thermal annealing at 500 and 600 °C, to compare structural, chemical, and electrical characteristics with reference to a TiN substrate. As a result, leakage current was suppressed to around 10-6 A/cm2 at 1 V, and an EOT at the 0.5 nm level was achieved.

L-asparaginase (ASNase) is a therapeutic enzyme used to treat acute lymphoblastic leukemia. Currently, the most widely used ASNases are originated from bacteria. However, owing to the adverse effects of bacterial ASNases, new resources for ASNase production should be explored. Fungal enzymes are considered efficient and compatible resources of natural products for diverse applications. In particular, fungal species belonging to the genus Trichoderma are well-known producers of several commercial enzymes including cellulase, chitinase, and xylanase. However, enzyme production by marine-derived Trichoderma spp. remains to be elucidated. While screening for extracellular ASNase-producing fungi from marine environments, we found four strains showing extracellular ASNase activity. Based on the morphological and phylogenetic analyses using sequences of translation elongation factor 1-alpha (tef1α), the Trichoderma isolates were identified as T. afroharzianum, T. asperellem, T. citrinoviride, and Trichoderma sp. 1. All four strains showed different ASNase activities depending on the carbon sources. T. asperellem MABIK FU00000795 showed the highest ASNase value with lactose as a carbon source. Based on our findings, we propose that marine-derived Trichoderma spp. are potential candidates for novel ASNase production.

In this study, a chlorination technique for recycling Li2ZrO3, a reaction product of ZrO2-assisted rinsing process, was investigated to minimize the generation of secondary radioactive pyroprocessing waste. It was found that the reaction temperature was a key parameter that determined the reaction rate and maximum conversion ratio. In the temperature range of 400−600℃, an increase in the reaction temperature resulted in a profound increase in the reaction rate. Hence, according to the experimental results, a reaction temperature of at least 450℃ was proposed to ensure a Li2ZrO3 conversion ratio that exceeded 80% within 8 h of the reaction time. The activation energy was found to be 102 ± 2 kJ·mol−1·K−1 between 450 and 500℃. The formation of LiCl and ZrO2 as reaction products was confirmed by X-ray diffraction analysis. The experimental results obtained at various total flow rates revealed that the overall reaction rate depends on the Cl2 mass transfer rate in the experimental condition. The results of this study prove that the chlorination technique provides a solution to minimize the amount of radioactive waste generated during the ZrO2-assisted rinsing process.

The reaction between Li2CO3 and Cl2 was investigated to verify its occurrence during a carbon-anode-based oxide reduction (OR) process. The reaction temperature was identified as a key factor that determines the reaction rate and maximum conversion ratio. It was found that the reaction should be conducted at or above 500℃ to convert more than 90% of the Li2CO3 to LiCl. Experiments conducted at various total flow rate (Q) / initial sample weight (W i) ratios revealed that the reaction rate was controlled by the Cl2 mass transfer under the experimental conditions adopted in this work. A linear increase in the progress of reaction with an increase in Cl2 partial pressure (pCl2) was observed in the pCl2 region of 2.03–10.1 kPa for a constant Q of 100 mL∙min−1 and W i of 1.00 g. The results of this study indicate that the reaction between Li2CO3 and Cl2 is fast at 650℃ and the reaction is feasible during the OR process.

Strontium is known as a salt-soluble element during the electrolytic oxide reduction (EOR) process. The chemical behavior of SrO during EOR was investigated via thermodynamic calculations to provide quantitative data on the chemical status of Sr. To achieve this, thermodynamic calculations were conducted using HSC chemistry software for various EOR conditions. It was revealed that SrO reacts with LiCl salt to produce SrCl2, even in the presence of Li2O, and that the ratio of SrCl2 depends on the initial concentration of Li2O dissolved in LiCl. It was found that SrO reacts with Li to produce Sr during EOR and that the reduced Sr reacts with LiCl salt to produce SrCl2. As a result, the proportions of metallic forms were lower in Sr than in La and Nd under various EOR conditions. The thermodynamic calculations indicated that the three chemical forms of SrO, SrCl2, and Sr co-exist in the EOR system under an equilibrium with Li, Li2O, and LiCl.

The corrosion behavior of Hastelloy C-276 was investigated to identify its applicability for carbon-anode-based oxide reduction (OR), in which Cl2 and O2 are simultaneously evolved at the anode. Under a 30 mL·min-1 Cl2 + 170 mL·min-1 Ar flow, the corrosion rate was less than 1 g·m-2·h-1 up to 500℃, whereas the rate increased exponentially from 500 to 700℃. The effects of the Cl2-O2 composition on the corrosion rate at flow rates of 30 mL·min-1 Cl2, 20 mL·min-1 Cl2 + 10 mL·min-1 O2, and 10 mL·min-1 Cl2 + 20 mL·min-1 O2 with a constant 170 mL·min-1 Ar flow rate at 600℃ was analyzed. Based on the data from an 8 h reaction, the fastest corrosion rate was observed for the 20 mL·min-1 Cl2 + 10 mL·min-1 O2 case, followed by 30 mL·min-1 Cl2 and 10 mL·min-1 Cl2 + 20 mL·min-1 O2. The effects of the chlorine flow rate on the corrosion rate were negligible within the 5–30 mL·min-1 range. A surface morphology analysis revealed the formation of vertical scratches in specimens that reacted under the Cl2-O2 mixed gas condition.

The corrosion behavior of the Inconel X-750 alloy was investigated for its potential application under a Cl2-O2 mixed gas flow in an Ar atmosphere. The corrosion rate was found to be negligible at temperatures up to 400℃ under a flow rate of 30 mL·min-1 Cl2 + 170 mL·min-1 Ar, whereas an exponential increase was observed in the corrosion rate at temperatures greater than 500℃. The suppression of the corrosion reaction due to the presence of O2 was verified experimentally at flow rates of 30 mL·min-1 Cl2 (4.96 g·m-2·h-1), 20 mL·min-1 Cl2 + 10 mL·min-1 O2 (2.02 g·m-2·h-1), and 10 mL·min-1 Cl2 + 20 mL·min-1 O2 (1.34 g·m-2·h-1) under a constant Ar flow rate of 170 mL·min-1 at 600℃ for 8 h. The surface morphology analysis results revealed that porous surfaces with tunnel-type holes were produced under the Cl2-O2 mixed-gas condition. Furthermore, the effects of the Cl2 flow rate on the corrosion rate were investigated, indicating that its impact was negligible within the range of 5–30 mL·min-1 Cl2 at 600℃.

Here, the stability of stainless steel 316 (SS-316) was investigated to identify its applicability in the oxide reduction process, as a component in related equipment, to produce a complicated gas mixture composed of O2 and Cl2 under an argon (Ar) atmosphere. The effects of the mixed gas composition were investigated at flow rates of 30 mL/min O2, 20 mL/min O2 + 10 mL/min Cl2, 10 mL/min O2 + 20 mL/ min Cl2, and 30 mL/min Cl2, each at 600℃, during a constant argon flow rate of 170 mL/min. It was found that the corrosion of SS-316 by the chlorine gas was suppressed by the presence of oxygen, while the reaction proceeded linearly with the reaction time regardless of gas composition. Surface observation results revealed an uneven surface with circular pits in the samples that were fed mixed gases. Thermodynamic calculations proposed the combination of Fe and Ni chlorination reactions as an explanation for this pit formation phenomenon. An exponential increase in the corrosion rate was observed with an increase in the reaction temperature in a range of 300 ~ 600℃ under a flow of 30 mL/min Cl2 + 170 mL/min Ar.

Momordica charantia is therophyte vine plants. It is called natural insulin and contains carantine and vitamin C and so on. Momordica charantia is one of the representative subtropical crops as a functional crop, showing efficacy on improvement of diabetes, cancer, abdominal obesity and improvement of hypertension. According to climate change, Momordica charantia is growing cultivation area, but there is still insufficient research for insect pest occurrence and insecticides. Due to the lack of proper control measures, the damage caused by insect pests is increasing as the year goes by. This study was conducted to investigate the occurrence and damage of insect pests in Momordica charantia and utilize it as basic data for development of insect pest control technology. As a result, 5 orders of 13 species of insect pests were investicated. Among them, Aphis gossypii, Frankliniella intonsa, and Frankliniella occidentalis showed high density. In particular, Aphis gossypii showed the highest density in mid-May, also Frankliniella intonsa and Frankliniella occidentalis showed high density in the middle of June. The leaf damage caused by the larvae of Palpita indica was observed in late June. After mid July, the biginning of the high temperature period, the insect pest density decreased, but the damages caused by moths were severe.