• Weed & Turfgrass Science
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• v.2 no.3
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• pp.242-247
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• 2013

Currently, methods for controlling weeds in organically produced crops have not been as effective as conventional methods. This research was carried out to determine the herbicidal effects of leaf, stem, fruit, root extracts of Trichosanthes kirilowii. The extraction methods used were water, boiling water and ethanol. The characteristics of potential herbicidal components among extraction methods were investigated by using the following solvent fractions: hexane, chloroform, ethyl acetate, butanol, and water. Generally, water extracts provided the best on inhibition of germination rate, plant height, and root length in cucumber and barley. Specifically, extractions made from fruit parts of T. kirilowii provided the greatest inhibition effect on plant growth in cucumber and barely. Inhibition of germination rate, plant height, and root length in cucumber and barley in solvent fractions was the best in water fractions, but there were no significant differences among the other fractions. Digitaria siliaris and Solanum nigrum were controlled 80-100% by 5% extractions of water fraction. However, there were no herbicidal effects from foliar treatment in cucumber, barley, black nightshade, and henry crabgrass by 5% extractions of the water fraction. These results show that extractions of T. kirilowii can be used for controlling some weeds in organically produced crops.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.5-5
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• 2011

The research and development of hybrid electric vehicle (HEV), plug-in hybrid electric vehicle (PHEV) and electric vehicle (EV) are intensified due to the energy crisis and environmental concerns. In order to meet the challenging requirements of powering HEV, PHEV and EV, the current lithium battery technology needs to be significantly improved in terms of the cost, safety, power and energy density, as well as the calendar and cycle life. One new technology being developed is the utilization of composite cathode by mixing two different types of insertion compounds [e.g., spinel $LiMn_2O_4$ and layered $LiMO_2$ (M=Ni, Co, and Mn)]. Recently, some studies on mixing two different types of cathode materials to make a composite cathode have been reported, which were aimed at reducing cost and improving self-discharge. Numata et al. reported that when stored in a sealed can together with electrolyte at $80^{\circ}C$ for 10 days, the concentrations of both HF and $Mn^{2+}$ were lower in the can containing $LiMn_2O_4$ blended with $LiNi_{0.8}Co_{0.2}O_2$ than that containing $LiMn_2O_4$ only. That reports clearly showed that this blending technique can prevent the decline in capacity caused by cycling or storage at elevated temperatures. However, not much work has been reported on the charge-discharge characteristics and related structural phase transitions for these composite cathodes. In this presentation, we will report our in situ x-ray diffraction studies on this mixed composite cathode material during charge-discharge cycling. The mixed cathodes were incorporated into in situ XRD cells with a Li foil anode, a Celgard separator, and a 1M $LiPF_6$ electrolyte in a 1 : 1 EC : DMC solvent (LP 30 from EM Industries, Inc.). For in situ XRD cell, Mylar windows were used as has been described in detail elsewhere. All of these in situ XRD spectra were collected on beam line X18A at National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory using two different detectors. One is a conventional scintillation detector with data collection at 0.02 degree in two theta angle for each step. The other is a wide angle position sensitive detector (PSD). The wavelengths used were 1.1950 ${\AA}$ for the scintillation detector and 0.9999 A for the PSD. The newly installed PSD at beam line X18A of NSLS can collect XRD patterns as short as a few minutes covering $90^{\circ}$ of two theta angles simultaneously with good signal to noise ratio. It significantly reduced the data collection time for each scan, giving us a great advantage in studying the phase transition in real time. The two theta angles of all the XRD spectra presented in this paper have been recalculated and converted to corresponding angles for ${\lambda}=1.54\;{\AA}$, which is the wavelength of conventional x-ray tube source with Cu-$k{\alpha}$ radiation, for easy comparison with data in other literatures. The structural changes of the composite cathode made by mixing spinel $LiMn_2O_4$ and layered $Li-Ni_{1/3}Co_{1/3}Mn_{1/3}O_2$ in 1 : 1 wt% in both Li-half and Li-ion cells during charge/discharge are studied by in situ XRD. During the first charge up to ~5.2 V vs. $Li/Li^+$, the in situ XRD spectra for the composite cathode in the Li-half cell track the structural changes of each component. At the early stage of charge, the lithium extraction takes place in the $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ component only. When the cell voltage reaches at ~4.0 V vs. $Li/Li^+$, lithium extraction from the spinel $LiMn_2O_4$ component starts and becomes the major contributor for the cell capacity due to the higher rate capability of $LiMn_2O_4$. When the voltage passed 4.3 V, the major structural changes are from the $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ component, while the $LiMn_2O_4$ component is almost unchanged. In the Li-ion cell using a MCMB anode and a composite cathode cycled between 2.5 V and 4.2 V, the structural changes are dominated by the spinel $LiMn_2O_4$ component, with much less changes in the layered $LiNi_{1/3}Co_{1/3}Mn_{1/3}O_2$ component, comparing with the Li-half cell results. These results give us valuable information about the structural changes relating to the contributions of each individual component to the cell capacity at certain charge/discharge state, which are helpful in designing and optimizing the composite cathode using spinel- and layered-type materials for Li-ion battery research. More detailed discussion will be presented at the meeting.

• Clean Technology
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• v.26 no.2
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• pp.91-95
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• 2020

A new eco-friendly synthetic method for N-hydroxysuccinimide (NHS), widely used in the pharmaceutical and fine chemical industries, is developed. Conventional synthesis method yields NHS of about 70% after its reaction with NH₂OH to succinic acid. In this method, NHS can be obtained using low-cost succinic acid, but a great deal of solvents are required as an extraction method to purify NHS, while the work-up process is complicated, resulting in low yield. In addition, there is a safety risk due to the high reaction temperature for commercial production, and it is not economical due to the high cost of production from the generation of much waste because of an acid catalyst and the use of various solvents. In order to make up for this shortcoming, this study used succinic anhydride as a raw material under low temperature reaction and developed a new eco-friendly industrial synthesis method using isobutyl alcohol for a single solvent and non-catalytic reaction. The economic evaluation confirms that there is a cost reduction effect of about 20%. In the future, based on this result, studies may establish a commercial production technology through scale-up research and proceed with foreign technology transfer.

• Korean Journal of Medicinal Crop Science
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• v.18 no.6
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• pp.421-428
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• 2010

The bark of Berberis koreana Palibin was fermented by Bifidobacterium longum B6 and Lactobacillus paracasei at $37^{\circ}C$ for 72 hour, then extracted by water solvent at $100^{\circ}C$ for 180 min. Total pholyphenol and flavonoid contents were improved by fermentation process, compared to conventional water extraction. The barks of B. koreana Palibin extracts by B. longum B6 (FE-B.L.) and by L. paracasei (FE-L.P.) showed 17% and 16% cytotoxicity on human normal cell lines(HEK293) at 1.0 mg/$m{\ell}$ of the highest concentration, respectively, which was about 3~5% lower than 20% from normal extracts (NE). DPPH radical scavenging activity of the FE-B.L. and FE-L.P. were about 73% and 75.9% higher than 56.8% of NE. The highest inhibitory potency on xathine oxidase and superoxide dismutase (SOD)-like activities were also measured as 31.9% and 61.9% by adding FE-L.P. of 1.0 mg/$m{\ell}$. On tyrosinase inhibition test, the FE-L.P. showed highest activity as 75.9% at 1.0 mg/$m{\ell}$. Generally, FE-L.P. showed higher antioxidant activities as well as higher tyrosinase inhibition activity, possibly due to high contents of total pholyphenol and flavonoid. In general, fermentation of barks of B. koreana Palibin has relatively better biological activities than normal extracts. Specifically, the extracts fermented by L. paracasei showed higher activities than that from B. longum B6.