Electric double layer capacitors employing nitrogen and sulfur co-doped, hierarchically porous graphene electrodes with synergistically enhanced performance

Kannan, Aravindaraj G.,Samuthirapandian, Amaresh,Kim, Dong-Won Elsevier 2017 Journal of Power Sources Vol.337 No.-

<P><B>Abstract</B></P> <P>Hierarchically porous graphene nanosheets co-doped with nitrogen and sulfur are synthesized via a simple hydrothermal method, followed by a pore activation step. Pore architectures are controlled by varying the ratio of chemical activation agents to graphene, and its influence on the capacitive performance is evaluated. The electric double layer capacitor (EDLC) assembled with optimized dual-doped graphene delivers a high specific capacitance of 146.6 F g<SUP>−1</SUP> at a current density of 0.8 A g<SUP>−1</SUP>, which is higher than that of cells with un-doped and single-heteroatom doped graphene. The EDLC with dual-doped graphene electrodes exhibits stable cycling performance with a capacitance retention of 94.5% after 25,000 cycles at a current density of 3.2 A g<SUP>−1</SUP>. Such a good performance can be attributed to synergistic effects due to co-doping of the graphene nanosheets and the presence of hierarchical porous structures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Nitrogen and sulfur co-doped, hierarchically porous graphene is synthesized. </LI> <LI> EDLC with co-doped graphene exhibits high capacitance and good cycling stability. </LI> <LI> Good performance is attributed to co-doping and hierarchical porous structures. </LI> </UL> </P>

우리나라 1개 농촌 지역 주민의 질병상태에 관한 조사 : 경기도 양주군 수동면

이옥엽,박순복,원규숙,이내숙,등영문 梨花女子大學校 醫科大學 1979 梨花醫學誌 Vol.11 No.-

Radiolysis of Paraffin Encapsulation Wax

Chang Lak Kim,Myung Chan Lee,Won Jae Park,Tae Won Suk,William G. Burns 대한방사선방어학회 1995 방사선방어학회지 Vol.20 No.4

Highly interconnected hollow graphene nanospheres as an advanced high energy and high power cathode for sodium metal batteries

Thangavel, Ranjith,Kannan, Aravindaraj G.,Ponraj, Rubha,Sun, Xueliang,Kim, Dong-Won,Lee, Yun-Sung The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.21

<P>Developing sodium based energy storage systems that retain high energy density at high power along with stable cycling is of paramount importance to meet the energy demands of next generation applications. This requires the development of electrodes beyond the conventional intercalation-based chemistry to overcome the sluggish diffusion-limited reaction kinetics and limited cycle life. Herein, we report a rationally designed hollow graphene nanosphere (HGS) cathode, which utilizes non-destructive, ultra-fast surface redox reactions at oxygen functional groups and delivers a discharge capacity of ∼155 mA h g<SUP>−1</SUP> (0.1 A g<SUP>−1</SUP>) corresponding to a high energy of ∼415 W h kg<SUP>−1</SUP> and retains ∼88 W h kg<SUP>−1</SUP> of energy at a remarkable specific power of ∼84 kW kg<SUP>−1</SUP> (40 A g<SUP>−1</SUP>), which are beyond the capabilities of intercalation-based electrodes. Moreover, the achieved cycling performance (86% capacity retention after 50 000 cycles at 10 A g<SUP>−1</SUP>) is the most stable cathode performance reported so far. The rationally designed sodium metal battery full cells with a sodium metal deposited aluminium current collector anode and the HGS cathode showed a similar sodium ion storage performance with high capacity, good rate capability, and stability. We certainly believe that the current research could direct the future research development towards transition metal-free, ultra-high power and super stable cathodes for sodium energy storage devices.</P>

Nitrogen- and sulfur-enriched porous carbon from waste watermelon seeds for high-energy, high-temperature green ultracapacitors

Thangavel, Ranjith,Kannan, Aravindaraj G.,Ponraj, Rubha,Thangavel, Vigneysh,Kim, Dong-Won,Lee, Yun-Sung The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.36

<P>Electrochemical ultracapacitors exhibiting high energy output and an ultra-long cycle life, utilizing green and sustainable materials, are of paramount importance for next-generation applications. Developing an ultracapacitor that has high output energy under high power conditions in a high-voltage non-aqueous electrolyte and maintaining a long cycle life is an ongoing challenge. Herein, we utilize watermelon seeds, a bio-waste from watermelons, for use in high-voltage, high-energy, and high-power ultracapacitors in a sodium ion-based non-aqueous electrolyte. The as-synthesized hierarchically porous, high surface area carbon is surface-engineered with a large quantity of nitrogen and sulfur heteroatoms to give a high specific capacitance of ∼252 F g<SUP>−1</SUP> at 0.5 A g<SUP>−1</SUP> and 90 F g<SUP>−1</SUP> at 30 A g<SUP>−1</SUP>. An ultra-high stability of ∼90% even after 150 000 cycles (10 A g<SUP>−1</SUP>) with 100% coulombic efficiency is achieved at room temperature (25 °C), equivalent to an ultra-low energy loss of ∼0.0667% per 1000 cycles. Furthermore, the porous carbon demonstrates remarkable stability even at high temperature (55 °C) for 100 000 cycles (10 A g<SUP>−1</SUP>), ensuring the safety of the device and enabling it to outperform graphene-based materials. A maximum energy of ∼79 W h kg<SUP>−1</SUP> and a maximum power of 22.5 kW kg<SUP>−1</SUP> with an energy retention of ∼28.2 W h kg<SUP>−1</SUP> was attained. The results provide new insights that will be of use in the development of high-performance, green ultracapacitors for advanced energy storage systems.</P>

우리나라 1개 농촌 지역 주민의 질병상태에 관한 조사 : 경기도 양주군 수동면 Su-Dong Myun, Yang-Ju Gun, Kyung-Gi Do

이옥엽,박순복,원규숙,이내숙,등영문 이화여자대학교 의과대학 1979 梨花醫學誌 Vol.- No.11

A study on the status of disease in a Korean rural Community, Su-Dong Myun, Yong Ju Gun, Kyung-Gi Do was carried out from December, 28 1978 to January, 19 1979 through analizing the meclical records of Su-Dong Health Subcenter during the period september, 1977 to August, 1978 and following results were obtained. 1. New cases of out patients were 5,695 composed of 49.1% male and 50.9% female during the study period. 2. Cumulative cases of out patients were 9,956 composed of 56.4% male and 43.6% female during the study period. 3. Annual morbidity rate was 908.6 per 1,000 for male and 986.4 for female and average annual morbidity rate was 946.6 per 1,00 population. 4. The highest morbidity rate was 3,660.0 as composed of aged 0∼4, the lowest was 498.4 as composed of aged 10∼14 per 1m000 population per year. 5. Following was the order of five major disease which were classified with I.C.D. ① Diseases of the respiratory system : 33.4% ② Diseases of the digestive system : 21.5% ③ Diseases of the skin and subcutaneous tissue : 15.4% ④ Diseases of the nervous system and sense organs : 7.9% ⑤ Accidents, poisonings and violence : 9.4% 6. The visiting rate in the health subcenter were 2.01 for male, 1.44 for female and the average 1.75 per each out patient. 7. Average medical fee per new case was 653±510 won and average cumulatived fee per case was 923±833 won. 8. The distribution of out patients according to the cost of medical fee, 48.9% of total new patients was treated with less than 500 won and 93.3% of new patients was treated with less than 1,000 won.

A SPECTRAL LINE SURVEY OF THE ULTRACOMPACT H II REGION G34.3+0.15. II: 155.3-165.3 GHZ

KIM HUN-DAE,CHO SE-HYUNG,LEE CHANG-WON,BURTON MICHAEL G. The Korean Astronomical Society 2001 Journal of The Korean Astronomical Society Vol.34 No.3

A molecular line survey towards the UC H II region G34.3+0.15 from 155.3 to 165.3GHz has been conducted with the TRAO 14-m radio telescope. Combined with our previous observations from 84.7 to 115.6GHz and 123.5 to 155.3GHz (Paper I), the spectral coverage of this survey in G34.3+0.15 now runs from 85 to 165 GHz. From these latest observations, a total of 18 lines from 6 species were detected. These include four new lines corresponding to ${\Delta}$J = 0, ${\Delta}$K = 1 transitions of the $CH_3OH$ E-type species, and two new lines corresponding to transitions from $SO_2$ and $HC_3N$. These 6 new lines are $CH_3OH$[1(1) - 1(0)E], $CH_3OH$[2(1) - 2(0)E], $CH_3OH$[3(1) - 3(0)E], $CH_3OH$[4(1) - 4(0)E], $SO_2$[14(1, 13) -14(0, 14)] and $HC_3N$[18 -17]. We applied a rotation diagram analysis to derive rotation temperatures and column densities from the methanol transitions detected, and combined with NRAO 12-m data from Slysh et al. 1999. Applying a two-component fit, we find a cold component with temperature 13-16K and column density $3.3-3.4 {\times} 10^{14} cm^{-2}$, and a hot component with temperature 64 - 83K and column density $9.3{\times}10^{14} - 9.7 {\times} 10^{14} cm^{-2}$. On the other hand, applying just a one-component fit yields temperatures in the 47 -62 K range and column densities from $7.5-1.1 {\times} 10^{15} cm^{-2}$.

Highly porous coral-like silicon particles synthesized by an ultra-simple thermal-reduction method

Ngo, Duc Tung,Le, Hang T. T.,Pham, Xuan-Manh,Jung, Ji-Won,Vu, Ngoc Hung,Fisher, John G.,Im, Won-Bin,Kim, Il-Doo,Park, Chan-Jin The Royal Society of Chemistry 2018 Journal of materials chemistry. A, Materials for e Vol.6 No.6

<P>Porous Si is considered a potential anode material for next-generation Li-ion batteries (LIBs) because of its high specific capacity, low lithiation/delithiation potential, low cost, and environmental friendliness. In this work, we introduce a simplified Mg-thermal-reduction method for the production of mass-scalable coral-like bulk-Si powder with a high surface area (38 m<SUP>2</SUP> g<SUP>−1</SUP>), broad pore-size distribution (2-200 nm), and 3-dimensionally (3D) interconnected Si structure for application in LIBs. The porous, coral-like Si electrode delivered a high reversible capacity of 2451 mA h g<SUP>−1</SUP>, corresponding to ∼70% of the theoretical capacity of Si, at a rate of C/10. After 100 cycles, the porous, coral-like Si electrode maintained a capacity of 1956 mA h g<SUP>−1</SUP>, corresponding to 79.8% of the initial reversible capacity. Importantly, a reasonably high reversible capacity of 614 mA h g<SUP>−1</SUP> was achieved even at a high rate of 10C. These outstanding results demonstrate that the 3D-networked, porous, coral-like Si powder, synthesized <I>via</I> a NaCl-assisted Mg-thermal-reduction process on a stainless-steel plate over a period of one minute, can be employed as a promising anode material for the next generation of high-energy LIBs.</P>

한우 미경산우에 대한 난소적출이 발육 및 도체형질에 미치는 영향

원유석,박노형,정준,정재경,임연수,박종관,이문걸 한국축산학회 1999 한국축산학회지 Vol.41 No.5

Five intact control(IC) and 5 ovariectomized heifers(OVX), born in the Livestock Improvement Main Center of National Livestock Co-operatives Federation, were used to study the effects of ovariectomy on growth and carcass traits. Ovariectomy was performed surgically at an average of 6 months old via an incision through the left lumbar fossa area. All heifers were fed concentrates and rice straw based on NLCF's feeding program. Heifers were slaughtered at an average of 24 months old and carcass traits were investigated according to the standard of the Animal Product Grading Service. Physical traits and chemical contents including fatty acids composition and cholesterol concentration in M. longissimus dorsi muscle were examined. Though feed intakes were not different, average daily gain of OVX was higher about 8.4% than that of IC, resulting in improved feed efficiency. The pH of the strip loin from OVX was higher than that of IC(OVX vs IC : 5.43 vs 5.36, P$lt;0.05), however, lowered in cholesterol content(OVX vs IC : 81.76 vs 89.36). Ovariectomy did not affect on tenderness and cooking loss but water holding capacity of the strip loin was higher than IC. Contents of myristic acid, palmitic acid, palmitoleic acid, stearic acid and oleic acid tended to be decreased by OVX, in contrast, linoleic acid was increased. Meat production index(MPI) and meat quality gade(MQG) were not influenced by ovariectomy. All of the OVX got lst grade in the carcass quality grade. Though an ovariectomy was little beneficial effects to improve the MPI and MQG items, overall meat quality grade of OVX was better than IC.

요추부의 고립성 골수종 1예

신원한,변박장,이인수,지제근 대한신경외과학회 1982 Journal of Korean neurosurgical society Vol.11 No.3

A 48-year-old male with back pain and foot drop had been treated. Studies for myelomatosis were all negative. A plain lumbar spine X-ray showed an erosion of the left pedicle of the first lumbar vertebra. A myelography via lumbar and cisternal routes revealed total block with feather appearance at the upper level of the L₂ and the lower level of the T_(12) vertebra. Pathologic evaluation confirmed the diagnosis of solitary myeloma of the bone. After undergoing almost total excision, followed by radiation, the patient was still doing well.