Atomic layer etching (ALE) is a promising technique with atomic-level thickness controllability and high selectivity based on self-limiting surface reactions. ALE is performed by sequential exposure of the film surface to reactants, which results in surface modification and release of volatile species. Among the various ALE methods, thermal ALE involves a thermally activated reaction by employing gas species to release the modified surface without using energetic species, such as accelerated ions and neutral beams. In this study, the basic principle and surface reaction mechanisms of thermal ALE?processes, including “fluorination-ligand exchange reaction”, “conversion-etch reaction”, “conversion-fluorination reaction”, “oxidation-fluorination reaction”, “oxidation-ligand exchange reaction”, and “oxidation-conversion-fluorination reaction” are described. In addition, the reported thermal ALE processes for the removal of various oxides, metals, and nitrides are presented.

It is necessary to fabricate uniformly dispersed nanoscale catalyst materials with high activity and long-term stability for polymer electrolyte membrane fuel cells with excellent electrochemical characteristics of the oxygen reduction reaction and hydrogen oxidation reaction. Platinum is known as the best noble metal catalyst for polymer electrolyte membrane fuel cells because of its excellent catalytic activity. However, given that Pt is expensive, considerable efforts have been made to reduce the amount of Pt loading for both anode and cathode catalysts. Meanwhile, the atomic layer deposition (ALD) method shows excellent uniformity and precise particle size controllability over the three-dimensional structure. The research progress on noble metal ALD, such as Pt, Ru, Pd, and various metal alloys, is presented in this review. ALD technology enables the development of polymer electrolyte membrane fuel cells with excellent reactivity and durability.

Atomic layer deposition (ALD) is widely used as a tool for the formation of near-atomically flat and uniform thin films in the semiconductor and display industries because of its excellent uniformity. Nowadays, ALD is being extensively used in diverse fields, such as energy and biology. By controlling the reactivity of the surface, either homogeneous or inhomogeneous coating on the shell of nanostructured powder can be accomplished by the ALD process. However, the ALD process on the powder largely depends on the displacement of powder in the reactor. Therefore, the technology for the fluidization of the powder is very important to redistribute its position during the ALD process. Herein, an overview of the three types of ALD reactors to agitate or fluidize the powder to improve the conformality of coating is presented. The principle of fluidization its advantages, examples, and limitations are addressed.

The design and fabrication of photoelectrochemical (PEC) electrodes for efficient water splitting is important for developing a sustainable hydrogen evolution system. Among various development approaches for PEC electrodes, the chemical vapor deposition method of atomic layer deposition (ALD), based on self-limiting surface reactions, has attracted attention because it allows precise thickness and composition control as well as conformal coating on various substrates. In this study, recent research progress in improving PEC performance using ALD coating methods is discussed, including 3D and heterojunction-structured PEC electrodes, ALD coatings of noble metals, and the use of sulfide materials as co-catalysts. The enhanced long-term stability of PEC cells by ALD-deposited protecting layers is also reviewed. ALD provides multiple routes to develop improved hydrogen evolution PEC cells.

Introduction : The obesity can be a serious problem that frequently induces a great deal of complications. Numerous methods have been applied to control obesity and one of them is aromatherapy. This study is a first attempt to verify the effect of the inhalation of essential oils on the obesity. This study was designed as the animal study, because the human study has many socio-psycho compounding variables. Methods : This study was designed to verify the effect of inhalation of essential oils on the body weight, feeding amount, food efficiency rate and serum leptin of SD rats. The research design is repeated measures over time, equivalent control group pretest-posttest experimental design. The subjects of this experiment were obese SD rats. They were allocated to one of four groups, the Fennel G., the Patchouli G., the Bergamot G. and control G. The experimental treatment was the inhalation of aromatherapy essential oils (Fennel, Patchouli, Bergamot). The experimental treatment was applied two times a day for 10 minutes each during 8 weeks. To evaluate the effect of inhalation of essential oils, the body weight, feeding amount and food efficiency rate was measured every week and serum leptin was measured before and after the experiment. The collected data was analyzed by repeated measures of ANOVA, Greenhouse-Geisser, ANOVA, Tukey, Kruskal Wallis test and χ²- test with SPSS program. Results : The results were as follows. The subjects of this study was 84 obese SD rats(40 males and 44 females). The means of age and body weight in obese SD rats were 30 weeks and 344.6g. The food efficiency rate was significantly lower in the Patchouli group and Fennel group than in Bergamot group and control group(P=.000). No significant group effects were found, but significant time effects were found for SD rat's body weight, feeding amount and serum leptin. Conclusions : In conclusion, these findings indicate that the inhalation of essential oils could be effective in lowering the food efficiency rate. 2)