• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.246-246
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• 2017

Salinity inhibits plant growth and restricts the efficiency of arbuscular mycorrhizal fungi. The selective uptake of nutrients from the soil and their effective transport to host roots make it essential for plant growth and development under salt stress. AMF spore associated bacteria shown to improve mycorrhizal efficiency under stress. Thus, this study aimed to understand the co-inoculation efficiency of AMF and SAB on maize growth and ion homeostasis under salt stress. Two AMF strains and one SAB were inoculated with maize either alone or in combination with one another. The results of our study showed that AMF and SAB co-inoculation significantly improved dry weight and nutrient uptake of maize under salt stress. Co-inoculation significantly reduced proline accumulation in shoots and Na+ accumulation in roots. Co-inoculation treatment also exhibited the high K+/Na+ ratios in roots at 25 mM NaCl. Mycorrhizal colonization showed positive influence for regulation of ZmAKT2, ZmSOS1 and ZmSKOR gene expressions, contributing to K+ and Na+ ion homeostasis. CLSM view showed that SAB were able move and localize into inter and intra cellular spaces of maize roots. In addition, CLSM view of AMF spores showed that gfp-tagged SAB also associated on the spore outer hyaline layer.

• 공업화학
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• 제31권3호
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• pp.305-309
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• 2020

본 연구에서는 에테르가 기능화된 이온성 액체인 [DMIm][MPEGP] (1,3-dimethylimidazolium (2-methoxy(2-ethoxy(2-ethoxy)))-ethylphosphite)와 리튬염인 LiTf₂N (lithium bis(trifluoromethanesulfonyl)imide)을 혼합하였고, 리튬염의 함량을 조절하여 전해질을 특성을 조사하였다. 제조된 전해질은 리튬염 혼합에 따라 불투명해지고 흐름성이 제한된 열방성 액정을 형성하였으며, 이때 리튬염의 함량에 따라 형성되는 이온성 액정의 자기조립구조와 이온 전도 현상을 다양한 분광학적 분석을 통해 조사하였다. 그 결과 이온성 액정의 향상된 이온전도도는 정렬된 구조를 통한 이온 전도 특성과 관계가 있음을 확인하였으며, 리튬이온전지 특성 평가에서 우수한 전기화학적 특성을 나타냄을 확인하였다.

• 한국전기전자재료학회논문지
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• 제18권2호
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• pp.125-129
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• 2005

Two kinds of physical treatments were examined for the analysis both of intrinsic surface and interior nature of CuInS $e_2$[CIS] and CuGaS $e_2$[CGS] films grown in separated systems. For the first method, a selenium protection layer which was immediately deposited after the growth of the CIS was investigated. The Se cap layer protects CISe surface from oxidation and contamination during the transport under ambient atmosphere. The Se cap was removed by thermal annealing at temperature above 15$0^{\circ}C$. After the decapping treatment at 2$25^{\circ}C$ for 60 min, ultraviolet photoemission and inverse photoemission measurements of the CIS film showed that its valence band maximum(VBM) and conduction band minimum (CBM) are located at 0.58 eV below and 0.52 eV above the Fermi level $E_{F}$, respectively. For the second treatment, an Ar ion beam etching was exploited. The etching with ion kinetic energy $E_{k}$ above 500 eV resulted in broadening of photoemission spectra of core signals and occasional development of metallic feature around $E_{F}$. These degradations were successfully suppressed by decreasing $E_{k}$ below 400 eV. CGS films etched with the beam of $E_{k}$ = 400 eV showed a band gap of 1.7 eV where $E_{F}$ was almost centered.st centered.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.344-349
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• 2016

Background: Carbon ion therapy has achieved satisfactory results. However, patients have a risk to get a secondary cancer. In order to estimate the risk, it is essential to understand particle transportation and nuclear reactions in the patient's body. The particle transport Monte Carlo simulation code is a useful tool to understand them. Since the code validation for heavy ion incident reactions is not enough, the experimental data of the elementary reaction processes are needed. Materials and Methods: We measured neutron production double-differential cross-sections (DDXs) on a carbon bombarded with 430 MeV/nucleon carbon beam at PH2 beam line of HIMAC facility in NIRS. Neutrons produced in the target were measured with NE213 liquid organic scintillators located at six angles of 15, 30, 45, 60, 75, and $90^{\circ}$. Results and Discussion: Neutron production double-differential cross-sections for carbon bombarded with 430 MeV/nucleon carbon ions were measured by the time-of-flight method with NE213 liquid organic scintillators at six angles of 15, 30, 45, 60, 75, and $90^{\circ}$. The cross sections were obtained from 1 MeV to several hundred MeV. The experimental data were compared with calculated results obtained by Monte Carlo simulation codes PHITS, Geant4, and FLUKA. Conclusion: PHITS was able to reproduce neutron production for elementary processes of carbon-carbon reaction precisely the best of three codes.

• 멤브레인
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• 제8권4호
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• pp.210-219
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• 1998

Fouling을 줄이기 위한 한외여과용 친수성 막을 제조하기 위해서 chlorosulfonic acid(CSA)를 사용하여 이온교환용량이 다른 여러 종류의 sulfonated polyethersulfone(SPES)을 불균일계에서 제조하고 특성조사를 하였다. CSA농도, 반응온도, 반응시간 등의 반응조건에 따른 반응도와 분해정도를 알아본 결과 10$\circ$C 이상의 온도와 0.05 mol 이상의 CSA 농도에서 효과적으로 반응이 일어나지만 고분자 주쇄의 분해가 심하게 일어나는 경향을 나타내었다. 술폰산기의 치환여부는 FTIR과 $^1$H-NMR로 확인할 수 있었다. 불균일계에서 개질된 SPES 한외여과막의 단백질에 의한 fouling 감소효과를 알아보기 위해 같은 투과성능을 갖는 막을 비용매인 DCM과 pore 형성제 PVP를 첨가제로 사용하여 막을 제조하였다. 이온교환용량이 증가함에 따라 투과속도는 감소하고 배제율은 상당히 증가되었다. 이런 결과는 SEM에 의해서도 확인할 수 있었다. Finger 구조가 사라지면서 top layer의 두께도 증가하였다. 비용매인 DCM에 의해서 치밀한 막을, pore 형성제인 PVP에 의해서 다공성 막을 제조할 수 있었다. 이온교환 용량이 높을수록 친수성이 증가하여 fouling을 감소시킬 수 있었다.

• Journal of Electrochemical Science and Technology
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• 제12권4호
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• pp.458-464
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• 2021

Lithium ion batteries (LIBs) is a kind of rechargeable secondary battery, developed from lithium battery, lithium ions move between the positive and negative electrodes to realize the charging and discharging of external circuits. Zeolitic imidazolate frameworks (ZIFs) are porous crystalline materials in which organic imidazole esters are cross-linked to transition metals to form a framework structure. In this article, ZIF-67 is used as a sacrificial template to prepare nano porous carbon (NPC) coated cobalt nanoparticles. The final product Co/NPC composites with complete structure, regular morphology and uniform size were obtained by this method. The conductive network of cobalt and nitrogen doped carbon can shorten the lithium ion transport path and present high conductivity. In addition, amorphous carbon has more pores that can be fully in contact with the electrolyte during charging and discharging. At the same time, it also reduces the volume expansion during the cycle and slows down the rate of capacity attenuation caused by structure collapse. Co/NPC composites first discharge specific capacity up to 3115 mA h/g, under the current density of 200 mA/g, circular 200 reversible capacity as high as 751.1 mA h/g, and the excellent rate and resistance performance. The experimental results show that the Co/NPC composite material improves the electrical conductivity and electrochemical properties of the electrode. The cobalt based ZIF-67 as the precursor has opened the way for the design of highly performance electrodes for energy storage and electrochemical catalysis.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.194-194
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• 2017

Camelina (Camelina sativa L.) is a potential bio-energy crop that has short life cycle about 90 days and contains high amount of unsaturated fatty acid which is adequate to bio-diesel production. Enhancing environmental stress tolerance is a main issue to increase not only crop productivity but also big mass production. CsRCI2s (Rare Cold Inducible 2) are cold and salt stress related protein that localized at plasma membrane (PM) and assume to be membrane potential regulation factor. These proteins can be divide into C-terminal tail (CsRCI2D/E/F/G) or no-tail group (CsRCI2A/B/C/H). However, function of CsRCI2s are less understood. In this study, physiological responses and functional characterization of CsRCI2s of Camelina under salt stress were analyzed. Full-length CsRCI2s (A/B/E/F) and CsPIP2;1 sequences were confirmed from Camelina genome browser. Physiological investigations were carried out using one- or four-week-old Camelina under NaCl stress with dose and time dependent manner. Transcriptional changes of CsRCI2A/B/E/F and CsPIP2;1 were determined using qRT-PCR in one-week-old Camelina seedlings treated with NaCl. Translational changes of CsRCI2E and CsPIP2;1 were confirmed with western-blot using the antibodies. Water transport activity and membrane potential measurement were observed by cRNA injected Xenopus laevis oocyte. As results, root growth rate and physiological parameters such as stomatal conductance, chlorophyll fluorescence, and electrolyte leakage showed significant inhibition in 100 and 150 mM NaCl. Transcriptional level of CsPIP2;1 did not changed but CsRCI2s were significantly increased by NaCl concentration, however, no-tail type CsRCI2A and CsRCI2B increased earlier than tail type CsRCI2E and CsRCI2F. Translational changes of CsPIP2;1 was constitutively maintained under NaCl stress. But, accumulation of CsRCI2E significantly increased by NaCl stress. CsPIP2;1 and CsRCI2A/B/E/F co-expressed Xenopus laevis oocyte showed decreased water transport activity as 61.84, 60.30, 62.91 and 76.51 % at CsRCI2A, CsRCI2B, CsRCI2E and CsRCI2F co-expression when compare with single expression of CsPIP2;1, respectively. Moreover, oocyte membrane potential was significantly hyperpolarized by co-expression of CsRCI2s. However, higher hyperpolarized level was observed in tail-type CsRCI2E and CsRCI2F than others, especially, CsRCI2E showed highest level. It means transport of $Na^+$ ion into cell is negatively regulated by expression of CsRCI2s, and, function of C-terminal tail is might be related with $Na^+$ ion influx. In conclusion, accumulation of NaCl-induced CsRCI2 proteins are related with $Na^+$ ion exclusion and prevent water loss by CsPIP2;1 under NaCl stress.

• Korean Chemical Engineering Research
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• 제48권3호
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• pp.283-291
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• 2010

리튬이온전지의 음전극으로 사용하기 위해 주로 알카리 수열합성법과 열처리에 의해 제조되는 $TiO_2$ 나노튜브의 전기화학적 특성에 관한 연구결과를 조사하여, 그 충방전 특성을 분석하였다. 현재까지 리튬과 $TiO_2$의 전기화학반응으로 생성되는 $Li_xTiO_2$의 이론용량인 $335mAh\;g^{-1}$(x=1)를 초과하는 최대방전용량 $338mAh\;g^{-1}$(x=1.01)을 $TiO_2(B)$ 상을 갖는 나노튜브가 나타내었다. 이것은 리튬의 자가확산이 활성에너지 0.48 eV 정도로 느리므로 이보다 확산거리가 짧도록 $TiO_2$ 나노튜브의 구조를 조정하여 리튬 수송이 원활하도록 하였기 때문이다. 또한 $TiO_2$ 나노튜브 구조체는 벌크상은 물론 표면에서의 뛰어난 이온저장성 때문에 리튬이온전지의 음전극 소재뿐만 아니라 고출력 특성이 필요한 커페시터 소자의 전극소재로도 활용할 수 있다.

• 대한기계학회논문집B
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• 제35권6호
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• pp.649-656
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• 2011

자동차용 리튬이온전지(lithium-ion batteries)의 성능향상 및 효과적인 셀 설계를 위한 준 2 차원 (pseudo-2-dimension) 해석 모델을 개발하였다. 전지 내부에 리튬, 리튬이온, 전자의 거동 및 계면에서 전해질과 활물질의 리튬이온 농도와 전기적 포텐셜 차이에 의한 전기화학 반응량 등을 계산할 수 있는 $Newman^{(1,2)}$ 모델을 기반에 변수 추정을 위한 최적화 기능을 추가하였다. 이 전기화학모델을 이용해 설계 변수, 재료의 물성 값 등의 의한 충/방전 특성을 계산할 수 있으며, 위치와 시간에 따른 전위, 농도, 생성전류량 등을 알 수 있다. 역으로 최적화 기능을 이용하여 실험에서 얻은 충/방전 곡선과 계산 값의 오차를 최소화하는 방법으로 측정이 어려운 물성값 추정이 가능하며 이를 이용하여 셀 성능 열화에 영향을 주는 변수 및 열화도를 예측할 수 있다. SB 리모티브에서 측정된 열화 과정의 방전 곡선들을 이용하여 최적화 해석을 수행하여 전지의 반복수명열화가 음극 및 양극활물질의 반응면적 및 전해질에 확산계수의 열화에 의한 것임을 알 수 있었다.

• Macromolecular Research
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• 제13권4호
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• pp.314-320
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• 2005

Crosslinked poly(vinyl alcohol) (PVA) membranes were prepared at various crosslinking temperatures using poly(acrylic acid-co-maleic acid) (PAM) containing different PAM contents. The thermal properties of these PVA/PAM membranes prepared at various reaction temperatures were characterized using differential scanning calorimetry (DSC). The proton conductivity and methanol permeability of PVA/PAM membranes were then investigated as PAM content was varied from 3 to 13 wt%. It was found that the proton and methanol transport were dependent on PAM content in their function both as crosslinking agent and as donor of hydrophilic -COOH groups. Both these properties decreased monotonously with increasing PAM concentration. The proton conductivities of these PVA/PAM membranes were in the range from $10^{-3}\;to\;10^{-2}S/cm$ and the methanol permeabilities from $10^{-7}\;to\;10^{-6}cm^{2}/sec$. In addition, the effect of operating temperature up to $80^{\circ}C$ on ion conductivity was examined for three selected membranes: 7, 9 and 11 wt% PAM membranes. Ion conductivity increased with increasing operating temperature and showed and S/cm at $80^{\circ}C$, respectively. The effects of crosslinking and ionomer group concentration were also examined in terms of water content, ion exchange capacity (IEC), and fixed ion concentration. In addition, the number of water molecules per ionomer site was calculated using both water contents and IEC values. With overall consideration for all the properties measured in this study, $7{\sim}9\;wt%$ PAM membrane prepared at $140^{\circ}C$ exhibited the best performance. These characteristics of PVA/PAM membranes are desirable in applications related to the direct methanol fuel cell (DMFC).