On the synthesis of a hierarchically-structured ZSM-5 zeolite and the effect of its physicochemical properties with Cu impregnation on cold-start hydrocarbon trap performance

Kim, Heejoong,Jang, Eunhee,Jeong, Yanghwan,Kim, Jinseong,Kang, Chun Yong,Kim, Chang Hwan,Baik, Hionsuck,Lee, Kwan-Young,Choi, Jungkyu Elsevier 2018 CATALYSIS TODAY - Vol.314 No.-

<P><B>Abstract</B></P> <P>A hierarchically structured zeolite (self-pillared pentasil; SPP) comprised of MFI nanosheets or lamellae has been synthesized in various Si/Al ratios and mesoporosities. It turns out that a simple removal of ethanol in a synthesis sol resulted in increased mesoporosity, while the additional reduction of water further increased mesoporosity. In addition, we could synthesize the SPP particle with the actual Si/Al ratio as low as ∼23 with a modest mesoporosity. With these hierarchically structured SPP particles, we further conducted copper impregnation on them in order to use as a hydrocarbon (HC) trap. The resulting Cu-impregnated SPPs could not only adsorb HCs in the exit gas stream including water vapor, but also serve as an active oxidizer of HCs. Specifically, Cu-impregnated SPP with an actual Si/Al ratio of ∼22 and medium mesoporosity exhibited very high performance in cold-start trap tests; desirably adsorbing propene and toluene even in the presence of 10 vol% steam, holding them up to higher temperatures (90 °C for propene and 190 °C for toluene), and furthermore, oxidizing the hydrocarbons. The preferred adsorption can be attributed to the larger amount of exchanged Cu<SUP>2+</SUP> ions in SPP particles with a lower Si/Al ratio, while the additional oxidation was due to the CuO particles dispersed on the SPP surface. However, the hydrothermal stability test revealed that the zeolite structure in the Cu-impregnated SPPs was collapsed and transformed into another undesired phase, thus losing the above-mentioned adsorption ability. Nevertheless, the corresponding oxidation performance was well maintained, indicating the robust, active role of the CuO particles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The mesoporosity in SPP particles was increased by removing ethanol and water. </LI> <LI> Mesoporous SPP particles with a Si/Al ratio as low as ∼23 could be synthesized. </LI> <LI> Cu-impregnated SPPs were effective for eliminating hydrocarbon (HC) in a cold start. </LI> <LI> The effect of physicochemical properties of SPPs on the HC trap was investigated. </LI> <LI> Cu<SUP>2+</SUP> ions increased HC adsorption, while CuO contributed to HC oxidation. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

열적전처리반응에서 발생하는 물질 거동 특성

김희중 ( Heejoong Kim ),김태경 ( Taekyoung Kim ),고광범 ( Gwangbeom Ko ),김연권 ( Younkwon Kim ),박선욱 ( Seonuk Park ) 한국물환경학회(구 한국수질보전학회) 2016 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2016 No.-

Comparison of characteristics during backward walking according to various stride frequencies in underwater and ground environments

Kim, Heejoong,Chung, Yijung korean Academy of Physical Therapy Rehabilitation 2018 Physical therapy rehabilitation science Vol.7 No.2

Objective: The purpose of this study was to investigate the relationship between heart rate (HR), self-awareness of exercise intensity (rating of perceived exertion, RPE), and 5-meter walk test (5MWT) of persons affected by stroke during backward walking according to the preferred stride frequency (PSF), PSF+3 and PSF+6 conditions. Design: Cross-sectional study. Methods: A total of 11 persons with stroke (9 males, 2 females) participated voluntarily. All patients underwent backward walking under the PSF, PSF+3, and PSF+6 conditions in underwater and ground environments, and each condition was performed for 5 minutes. The HR, RPE, and walking speeds were measured during walking, and the measured values from underwater and ground environments were compared. Results: The HR and RPE in the ground environment were significantly increased (p<0.05), and although the 5MWT showed an increase in speed, it was not significant. The HR and RPE in the underwater environment were also significantly increased (p<0.05), however, although the 5MWT results was increased, it was not significant. The HR and RPE were significantly increased in the PSF+6 condition (p<0.05). Conclusions: The results of this study showed that backward gait training underwater can provide an appropriate exercise intensity for stroke survivors and suggests that exercises performed in an underwater environment is more effective compared to the ground environment.

Diet source of Euphausia pacifica revealed using carbon- and nitrogen-stable isotopes in the Yellow Sea Cold Water Mass in summer

Kim, Heejoong,Ju, Se-Jong,Kang, Jung-Hoon,Shin, Kyung-Hoon Springer-Verlag 2019 Journal of oceanography Vol.75 No.1

Comparison of characteristics during backward walking according to various stride frequencies in underwater and ground environments

( Heejoong Kim ),( Yijung Chung ) 물리치료재활과학회 2018 Physical therapy rehabilitation science Vol.7 No.2

Objective: The purpose of this study was to investigate the relationship between heart rate (HR), self-awareness of exercise intensity (rating of perceived exertion, RPE), and 5-meter walk test (5MWT) of persons affected by stroke during backward walking according to the preferred stride frequency (PSF), PSF+3 and PSF+6 conditions. Design: Cross-sectional study. Methods: A total of 11 persons with stroke (9 males, 2 females) participated voluntarily. All patients underwent backward walking under the PSF, PSF+3, and PSF+6 conditions in underwater and ground environments, and each condition was performed for 5 minutes. The HR, RPE, and walking speeds were measured during walking, and the measured values from underwater and ground environments were compared. Results: The HR and RPE in the ground environment were significantly increased (p<0.05), and although the 5MWT showed an increase in speed, it was not significant. The HR and RPE in the underwater environment were also significantly increased (p<0.05), however, although the 5MWT results was increased, it was not significant. The HR and RPE were significantly increased in the PSF+6 condition (p<0.05). Conclusions: The results of this study showed that backward gait training underwater can provide an appropriate exercise intensity for stroke survivors and suggests that exercises performed in an underwater environment is more effective compared to the ground environment.

Effect of Underwater Gait Training with a Progressive Increase in Speed on Balance, Gait, and Endurance in Stroke Patients

Kim, Heejoong,Chung, Yijung The Korean Society of Physical Therapy 2019 대한물리치료학회지 Vol.31 No.4

Purpose: This study aimed to investigate the effect of progressive speed increase during underwater gait training on stroke patients' balance, gait, and endurance, as well as to compare the effects of underwater gait training and land gait training. Methods: Subjects were randomly allocated into three groups. Underwater gait training group (n=10), land gait training group (n=9) and control group (n=9). The groups performed their respective programs as well as conventional physical therapy 3 times/week for 8 weeks. The patients were assessed before and after the experiment in terms of the Berg balance scale, characteristics of gait, and 6-minute walking test. Results: The beneficial effect perceived in the speed increase underwater gait training (UGT) group was significantly greater than in the groups who were trained with speed increase land gait training (LGT) group, and the control group regarding the following aspects: the Berg balance scale, the affected step length, the affected stride length, and the 6-minute walking test (p<0.05). The LGT group showed a more significant effect on the Berg balance scale, the affected step length, the affected stride length, and the 6-minute walking test (p<0.05), compared to the control group. Furthermore, the UGT group showed a significantly greater effect on the gait speed when compared to the control groupb (p<0.05). Conclusion: This study shows that progressive UGT is effective in improving balance, gait, and endurance in stroke patients. Therefore, we believe that progressive UGT may be used as a method for general physical therapy in patients with stroke.

Utility of Stable Isotope and Cytochrome Oxidase I Gene Sequencing Analyses in Inferring Origin and Authentication of Hairtail Fish and Shrimp

Kim, Heejoong,Kumar, K. Suresh,Hwang, Seung Yong,Kang, Byeong-Chul,Moon, Hyo-Bang,Shin, Kyung-Hoon American Chemical Society 2015 Journal of agricultural and food chemistry Vol.63 No.22

<P>Mislabeling of fishery products continues to be a serious threat to the global market. Consequently, there is an urgent necessity to develop tools for authenticating and establishing their true origin. This investigation evaluates the suitability of stable isotopes and cytochrome oxidase I (COI) sequencing in identifying and tracing the origin of hairtail fish and shrimp. By use of COI sequencing, the hairtail fish samples were identified as <I>Trichiurus japonicus</I> and <I>Trichiurus lepturus</I>, while the shrimp samples were identified as <I>Pandalus borealis</I>, <I>Marsupenaeus japonicus</I>, <I>Fenneropenaeus chinensis</I>, <I>Litopenaeus vannamei</I>, <I>Penaeus monodon</I>, and <I>Solenocera crassicornis</I>. Linear discriminant analysis (LDA) of stable isotopes further categorized the individuals of the same species based on the country of origin. Natural and farmed shrimp (from the same country) were distinctly differentiated on the basis of stable isotope values. Therefore, these two methods could be cooperatively utilized to identify and authenticate fishery products, the utilization of which would enhance transparency and fair trade.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jafcau/2015/jafcau.2015.63.issue-22/acs.jafc.5b01469/production/images/medium/jf-2015-014698_0004.gif'></P>

Effect of Underwater Gait Training with a Progressive Increase in Speed on Balance, Gait, and Endurance in Stroke Patients

( Heejoong Kim ),( Yijung Chung ) 대한물리치료학회 2019 대한물리치료학회지 Vol.31 No.4

Purpose: This study aimed to investigate the effect of progressive speed increase during underwater gait training on stroke patients’ balance, gait, and endurance, as well as to compare the effects of underwater gait training and land gait training. Methods: Subjects were randomly allocated into three groups. Underwater gait training group (n=10), land gait training group (n=9) and control group (n=9). The groups performed their respective programs as well as conventional physical therapy 3 times/week for 8 weeks. The patients were assessed before and after the experiment in terms of the Berg balance scale, characteristics of gait, and 6-minute walking test. Results: The beneficial effect perceived in the speed increase underwater gait training (UGT) group was significantly greater than in the groups who were trained with speed increase land gait training (LGT) group, and the control group regarding the following aspects: the Berg balance scale, the affected step length, the affected stride length, and the 6-minute walking test (p<0.05). The LGT group showed a more significant effect on the Berg balance scale, the affected step length, the affected stride length, and the 6-minute walking test (p<0.05), compared to the control group. Furthermore, the UGT group showed a significantly greater effect on the gait speed when compared to the control groupb (p<0.05). Conclusion: This study shows that progressive UGT is effective in improving balance, gait, and endurance in stroke patients. Therefore, we believe that progressive UGT may be used as a method for general physical therapy in patients with stroke.

On methanol to hydrocarbons reactions in a hierarchically structured ZSM-5 zeolite catalyst

Kim, Heejoong,Jang, Hoi-Gu,Jang, Eunhee,Park, Sung Jun,Lee, Taehee,Jeong, Yanghwan,Baik, Hionsuck,Cho, Sung June,Choi, Jungkyu Elsevier Science Publishers 2018 Catalysis today Vol.303 No.-

<P><B>Abstract</B></P> <P>Two type ZSM-5 catalysts (Si/Al ratio of ∼30) with different mesoporosity were synthesized by using a structure directing agent of tetra-<I>n</I>-butylphosphonium hydroxide. In particular, the molar compositions of ethanol and water in the synthetic precursor were changed in order to acquire the two type ZSM-5 catalysts. The resulting ZSM-5 catalysts were formed via the interconnection of very thin pillars or lamellae; (1) ∼6nm thick with marked mesoporosity (H_30; high mesoporous ZSM-5) and (2) ∼13nm thick without any considerable mesoporosity (L_30; low mesoporous ZSM-5). The pyridine-based acid titration reveals that H_30 had internal Brønsted acid sites similar to those in the commercially available ZSM-5 with a Si/Al ratio of 75 (referred to as C_75), though H_30 contained a large amount of external Brønsted acid sites. The methanol to hydrocarbons (MTH) reaction performance of these two ZSM-5 catalysts demonstrates that H_30 preferred to produce propene over ethene compared to C_75, while L_30 showed a very poor MTH performance mainly due to the lower amount of internal Brønsted acid sites. More desirably, a very short diffusional length (∼18,600 times lower than that in C_75) in H_30 considerably disfavored the aromatic dealkylation that is known to produce ethene. With this, H_30 allowed for achieving the ratio of propene to ethene as high as ∼9.1, which is, to the best of our knowledge, a highest value among the MTH results on ZSM-5 catalysts without any co-feed. Furthermore, ceria-doped H_30 not only enhanced the stability for the MTH reaction via a passivation of the external Brønsted acid sites, but also improved a propene to ethene ratio up to ∼15.0.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hierarchically structured ZSM-5 catalysts were synthesized via self-pillaring. </LI> <LI> Mesopores in the range of 2–10nm were formed due to the space among the pillars. </LI> <LI> The self-pillared ZSM-5 was used for methanol to hydrocarbons (MTH) reactions. </LI> <LI> Reduced diffusion length in a catalyst allowed for a selective production of propene. </LI> <LI> The propene/ethene ratio as high as 9.1 from the MTH reaction was achieved. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

열가수분해 공정을 이용한 하수슬러지의 감량화 및 재이용

김희중(Heejoong Kim),고광범(Gwangbeom Ko),김연권(Younkwon Kim),배복제(Bokje Bae),유선경(Sunkyung You) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.5-2