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Emission of particulate and gaseous pollutants from household laser processing machine

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Journal of Environmental Sciences 2021年第5期33卷 148-156页

作者： Hyun sik Ko Sang Bin Jeong Sooyeol Phyo Jiwon Lee Jae Hee jung Department of Mechanical Engineering Sejong UniversitySeoul 05006Republic of Korea Center for Environment Healthand Welfare ResearchKorea Institute of Science and Technology(KIST)Seoul 02792Republic of Korea Graduate School of Energy and Environment Korea UniversitySeoul 02841Republic of Korea Department o f Materials Science and Engineering Korea UniversitySeoul 02841Republic of Korea

Indoor air quality(IAQ) directly affects the health of occupants. Household manufacturing equipment(HME) used for hobbies or educational purposes is a new and unexplored source of air pollution. In this study, we evaluated the characteristics of particulate and gaseous pollutants produced by a household laser processing equipment(HLPE). Various target materials were tested using a commercial HLPE under various operating conditions of laser power and sheath air flow rate. The mode diameters of the emitted particles gradually decreased as laser power increased, while the particle number concentration(PNC) and particle emission rate(PER) increased. In addition, as the sheath air flow rate quadrupled from 10 to 40 L/min, the mode diameter of the emitted particles decreased by nearly 25%, but the effect on the PNC was insignificant. When the laser induced the target materials at 53 m W, the mode diameters of particles were 2.0 × 10^(4) particles/cm^(3). Particularly, analyses of sampled aerosols indicated that harmful substances such as sulfur and barium were present in particles emitted from leather. The carcinogenic gaseous pollutants such as acrylonitrile, acetaldehyde, 1,3-butadiene, benzene, and C 8 aromatics(ethylbenzene) were emitted from all target materials. In an actual indoor environment, the PNC of inhalable ultrafine particles(UFPs) was > 5 × 10^(4) particles/cm^(3) during 30 min of HLPE operation. Our results suggest that more meticulous control methods are needed, including the use of less harmful target materials along with filters or adsorbents that prevent emission of pollutants.

关键词： Indoor air quality(IAQ) Emission Laser processing Ultrafine particles(UFPs) Volatile organic compounds(VOCs)

Value of controlled attenuation parameter in fibrosis prediction in nonalcoholic steatohepatitis

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World Journal of Gastroenterology 2019年第33期25卷 4959-4969页

作者： jung Il Lee Hyun Woong Lee Kwan sik Lee Department of Internal Medicine Gangnam Severance Hospital Yonsei University College of Medicine

BACKGROUND Liver stiffness measurement(LSM)tends to overestimate fibrosis stage in nonalcoholic fatty liver disease(naFLD).Controlled attenuation parameter(CAP),provided by LSM device,has been introduced for noninvasive quantification of hepatic *** To determine the role of CAP values in predicting liver fibrosis stage by LSM in nonalcoholic steatohepatitis(naSH).METHODS One hundred eighty-four patients with biopsy proven naSH had LSM and CAP evaluated at *** them,130 patients had 1-year follow up LSM and analyzed for the changes of LSM after pioglitazone or ursodeoxycholic acid(UDCA)*** In Kleiner fibrosis stage F0-1,LSM values increased at higher CAP tertile(P=0.001),and in F2,at middle and higher tertiles(P=0.027).No difference across CAP tertiles was noticed in F3-4(P=0.752).Receiver operating characteristic curve for LSM cutoff in diagnosis of F≥2 identified 8.05 kPa for lower CAP tertile,9.35 kPa for middle,and 10.55 kPa for high *** changes in proportion of significant fibrosis(F≥2)were assessed among pioglitazone and UDCA treated patients considering CAP values,pioglitazone treated patients demonstrated decrease in proportion of high *** In patient with naFLD,interpretation of LSM in association with CAP scores may provide helpful information sparing unnecessary liver biopsy.

关键词： Fibroscan Controlled attenuation parameter Liver stiffness Nonalcoholic steatohepatitis Liver fibrosis

Synergistic passivation of MAPbI_(3) perovskite solar cells by compositional engineering using acetamidinium bromide additives

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Journal of Energy Chemistry 2021年第8期30卷 755-762,I0016页

作者： Kyungeun jung Weon-sik Chae Jae Won Choi Ki Chul Kim Man-Jong Lee Department of Chemistry Konkuk University143-701 SeoulSouth Korea Department of Advanced Technology Fusion Konkuk University143-701 SeoulSouth Korea Analysis Research Division Daegu CenterKorea Basic Science Institute702-701 DaeguSouth Korea Division of Chemical Engineering Konkuk University05029 SeoulSouth Korea

For the global commercialization of highly efficient and stable perovskite solar cells(PSCs),it is necessary to effectively suppress the formation of various defects acting as nonradiative recombination sources in perovskite light-harvesting *** defects between the charge-selective layer and the perovskite are easily formed in the solution process used to fabricate perovskite *** addition,owing to the difference in thermal expansion coefficients between the substrate and the perovskite film,internal residual tensile stress inevitably occurs,resulting in increased nonradiative ***,a simple compositional engineering scheme for realizing efficient and stable PSCs,which incorporates acetamidinium bromide(AABr)as an additive into the MAPbI_(3) lattice,is *** an additive,AABr has been found to provide synergistic multiple passivation for both internal and interfacial *** was found to effectively release the tensile strain of the MAPbI_(3) film by forming a structure stabilized by NH-I hydrogen bonds,as evidenced by calculations based on density functional theory(DFT).Furthermore,the incorporated AABr additives created a charge carrier recombination barrier to enhance charge collection capability by reducing interfacial ***,a power conversion efficiency(PCE)of 20.18%was achieved using a planar device employing AABr-incorporated MAPbI_(3).This was substantially higher than the 18.32% PCE of a pristine MAPbI_(3)-based ***,unencapsulated PSCs using AABr-incorporated MAPbI_(3) absorbers exhibited excellent long-term stability,maintaining>95% of initial PCE up to 1200 hours in ambient air.

关键词： Acetamidinium bromide Planar perovskite solar cell Tensile stress Interface passivation Recombination barrier

Clinicopathological features of familial adenomatous polyposis in Korean patients

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World Journal of Gastroenterology 2016年第17期22卷 4380-4388页

作者： Sung Min jung Yong sik Yoon Seok-Byeong Lim Chang sik Yu Jin Cheon Kim Division of Colon and Rectal Surgery Department of Surgery University of Ulsan College of Medicine Seoul 05505 South Korea Asan Medical Center Seoul 05505 South Korea

AIM: To identify prognostic factors and to correlate APC mutations with clinical features, including extracolic manifestations. METHODS: One hundred thirty-five patients who underwent surgical procedures for familial adenomatous polyposis(FAP) were included. FAP was diagnosed when the number of adenomatous polyps was > 100. Data related to patient, extracoloic manifestations, cancer characteristics, operative procedure, follow up and surveillance were collected. APC mutation testing was performed in the 30 most recent patients. Dna was extracted from peripheral blood and polymerase chain reaction products using 31 primer pairs on APC gene were sequenced. A retrospective study was performed to investigate a causal relationship between prognosis and feature of ***: The mean age of the 51 patients with colorectal cancer(CRC) was older than that of those without CRC(30.5 vs 36.9, P = 0.002). Older individuals were more likely to have colon cancer at the time of FAP diagnosis [odds ratio, 4.75(95%CI: 1.71-13.89) and 5.91(1.76-22.12) for 40-49 years and age > 50 vs age nant rectal or ileal mucosa after surgery was not observed. The APC mutation testing revealed 23 pathogenic mutations and one likely pathogenic mutation, among which were four novel mutations. The correlation between mutational status and clinical manifestations was investigated. Mutations that could prodict poor prognosis were at codon 1309 which located on mutation cluster region, codon 1465 and codon ***: Identification of APC mutations should aid in the diagnosis and counseling of family members in terms of early diagnosis and management of FAP.

关键词： Adenomatous polyposis coli Colorectal neoplasms APC gene Prognosis Survival

Trap and 1/f-noise effects at the surface and core of GaN nanowire gateall-around FET structure

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nano Research 2019年第4期12卷 809-814页

作者： Mallem Siva Pratap Reddy Ki-sik Im jung-Hee Lee Raphael Caulmione Sorin Cristoloveanu School of Electronics Engineering Kyungpook National University Daegu 41566 Republic of Korea Advanced Material Research Center Kumoh National Institute of Technology Gumi 39177 Republic of Korea SOITEC Bernin 38190 France Institute of Microelectronics Electromagnetism and Photonics Grenoble Polytechnic Institute Minatec Grenoble 38016 France

Using capacitance,conductance and noise measurements,we investigate the trapping behavior at the surface and in the core of triangular-shaped one-dimensional (1 D) array of GaN nanowire gate-all-around field effect transistor (GAA FET),fabricated via a top-down *** surface traps in such a low dimensional device play a crucial role in determining the device *** estimated surface trap density rapidly decreases with increasing frequency,ranging from 6.07 × 1012 cm-2·eV-1 at 1 kHz to 1.90 × 1011 cm-2·eV-1 at 1 MHz,*** noise results reveal that the power spectral density increases with gate voltage and clearly exhibits 1/f-noise signature in the accumulation region (Vgs > Vth =3.4 V) for all *** the surface depletion region (1.5 V nal generation-recombination (G-R),mostly caused by the electron trapping/detrapping process through deep traps located in the surface depletion region of the *** cutoff frequency for the 1/f2 noise characteristics further shifts to lower frequency of 102-103 Hz when the device operates in deep-subthreshold region (Vgs nanowire core and the G-R noise prevails in the entire nanowire channel.

关键词： gate-all-around field effect transistor (FET) nanowire GaN trap 1/f-noise

2.47 GPa grade ultra-strong 15Co-12Ni secondary hardening steel with superior ductility and fracture toughness

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Journal of Materials Science & Technology 2021年第7期66卷 36-45页

作者： Young-Kyun Kim Kyu-sik Kim Young-Beum Song jung Hyo Park Kee-Ahn Lee Department of Materials Science and Engineering Inha UniversityIncheon22212Republic of Korea Agency for Defense Development(ADD) Yuseong-guDaegeon34186Republic of Korea

This study investigated the effect of multi-step heat treatment on the microstructure, mechanical properties and fracture behavior of thick 15 Co-12 Ni secondary hardening steel. As-quenched sample was found to have elongated prior austenite grain(PAG) and coarse lenticular martensitic structure. On the other hand, heat-treated sample was observed to have fine lenticular martensitic structure due to fine PAG size and a lot of nano-sized carbides. Also, after heat treatment, nano-scale reverted austenite film was formed at the martensite interfaces. The heat-treated sample showed 2.47 GPa superior tensile strength and superior elongation of about 12 %. The high strength was mainly due to fine block size and high number density of nano-sized carbides. The average value of plane strain fracture toughness(KIC) was 29.3 MPa m1/2, which indicated a good fracture toughness even with the high tensile strength. The tensile fracture surface was observed to have ductile fracture mode(cup-and-cone) and the formation of about ~1 μm ultra-fine dimples. In addition to this, nano-sized carbides were observed within the *** findings suggested that the nano-sized carbide had a positive effect not only on the strength but also on the ductility of the alloy. The fractured surface after toughness test, also showed ductile fracture mode with a lot of dimples. Based on the above results, correlation among microstructural evolution,deformation and fracture mechanisms along the heat-treatment was also discussed.

关键词： Ultra-high strength High Co-Ni secondary hardening steel Microstructure Tensile properties Fracture toughness Reverted austenite

Intelligent reflecting surface for sum rate enhancement in MIMO systems

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Digital Communications and Networks 2024年第1期10卷 94-100页

作者： Chan-Yeob Park Ji-Sung jung Yeong-Rong Lee Beom-sik Shin Hyoung-Kyu Song Department of Information and Communication Engineering Sejong UniversitySeoulGwangjin-guGunja-dong 98Republic of Korea Department of Convergence Engineering for Intelligent Drone Sejong University SeoulGwangjin-guGunja-dong 98Republic of Korea

The research for the Intelligent Reflecting Surface(IRS)which has the advantages of cost and energy efficiency has been *** capacity can be effectively increased by appropriately setting the phase value of IRS elements according to the channel ***,the problem of obtaining an appropriate phase value of IRs is difficult to solve due to the non-convex *** paper proposes an iterative algorithm for the alternating optimal solution in the Single User Multiple-Input-Multiple-Output(SU-MIMO)*** proposed iterative algorithm finds an alternating optimal solution that is the phase value of IRS one by *** results show that the proposed method has better performance than that of the randomized IRS *** number of iterations for maximizing the performance of the proposed algorithm depends on the channel state between the IRS and the receiver.

关键词： Intelligent reflecting surface MIMO Sum rate

Pyruvate dehydrogenase kinase is a negative regulator of interleukin-10 production in macrophages

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Journal of Molecular Cell Biology 2020年第7期12卷 543-555页

作者： Yi Rang na Daun jung Juha Song Jong-Wan Park jung Joo Hong Seung Hyeok Seok Macrophage Lab Department of Microbiology and Immunology and Institute of Endemic DiseaseSeoul National University College of MedicineChongno-guSeoul 03080Republic of Korea Department of Biomedical Science BK21-Plus Education ProgramSeoul National University College ofMedicineJongno-guSeoul 03080Republic of Korea Department of Pharmacology Seoul National University College of MedicineJongno-guSeoul 03080Republic of Korea Cancer Research Institute and Ischemic/Hypoxic Disease Institute Seoul National University College ofMedicineJongno-guSeoul 03080Republic of Korea national Primate Research Center Korea Research Institute of Bioscience and BiotechnologyCheongju 28116Republic of Korea

Interleukin-10(IL-10)is the most potent anti-inflammatory cytokine in the body and plays an essential role in determining outcomes of many inflammatory *** metabolism is a critical determinant of immune cell function;however,it is currently unclear whether metabolic processes are specifically involved in IL-10 *** this study,we aimed to find the central metabolic molecule regulating IL-10 production of macrophages,which are the main producers of *** analysis identified that metabolic changes were predominantly enriched in Kupffer cells at the early inflammatory phase of a mouse endotoxemia *** them,pyruvate dehydrogenase kinase(PDK)-dependent acute glycolysis was negatively involved in IL-10 *** or knockdown of PDK selectively increased macrophage IL-10 ***,PDK inhibition increased IL-10 production via profound phosphorylation of adenosine monophosphate(AMP)-activated protein kinase alpha 1(AMPKα1)by restricting glucose uptake in lipopolysaccharide-stimulated ***α1 consequently activated p38 mitogen-activated protein kinase,c-Jun N-terminal kinase,and cyclic AMP-responsive element-binding protein to regulate IL-10 *** study uncovers a previously unknown regulatory mechanism of IL-10 in activated macrophages involving an immunometabolic function of PDK.

关键词： macrophage pyruvate dehydrogenase kinase AMP-activated protein kinase interleukin-10

Experiments and computer simulation analysis of impact behaviors of micro-sized abrasive in waterjet cutting of thin multiple layered materials

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中国有色金属学会会刊：英文版 2012年第S3期22卷 864-869页

作者： jung-Han LEE Kang-Su PARK Myung Chang KANG Bo sik KANG Bo Sung SHIN Engineering Research Center Pusan National University national Core Research Center Pusan National University Mechanical System Safety Research Division Korea Institute of Machinery and Materials

The abrasive waterjet (AWJ) is now widely used in the advanced cutting processes of polymers,metals,glass,ceramics and composite materials like thin multiple-layered material (TMM).Various research and development efforts have recently been made to understand the science of ***,the interaction mechanism between a workpiece and high-velocity abrasive particles still remains a complicated *** this work,the material removal mechanisms of AWJ such as micro penetration and micro dent were experimentally *** addition,a new computer simulation model considering high strain rate effect was proposed to understand the micro impact behavior of high-velocity micro-sized abrasives in AWJ cutting.

关键词： abrasive waterjet thin multiple layered materials micro-sized abrasive micro penetration micro dent