• 전기화학회지
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• 제9권4호
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• pp.158-169
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• 2006

The present article is concerned with the overview of the chemically/surface modified cubic spinel $LiMn_2O_4$ as a cathode electrode far lithium ion secondary batteries. Firstly, this article presented a comprehensive survey of the cubic spinel structure and its correlated electrochemical behaviour of $LiMn_2O_4$. Subsequently, the various kinds of the chemically/surface modified $LiMn_2O_4$ and their electrochemical characteristics were discussed in detail. Finally, this article reviewed our recent research works published on the mechanism of lithium transport through the chemically/surface modified $Li_{1-\delta}Mn_2O_4$ electrode from the kinetic view point by the analyses of the experimental potentiostatic current transients and ac-impedance spectra.

• 호남수학학술지
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• 제46권2호
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• pp.279-290
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• 2024

In this study, tubular surfaces were introduced according to the modified orthogonal frame defined at the points where the torsion is different from zero in the 3-dimensional Euclidean space. First, the relations between the Frenet frame and the modified orthogonal frame with torsion are given. Then, the singularity, Gaussian curvature, mean curvature and basic forms of the tubular surface given according to the modified orthogonal frame with torsion were calculated. In addition, the conditions for the parameter curves of the tubular surface to be geodesic, asymptotic and line of curvature were examined. Finally, tubular surface examples based on both the Frenet frame and the modified orthogonal frame with torsion were given to support the study.

• Corrosion Science and Technology
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• 제13권5호
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• pp.170-177
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• 2014

Polyurethane coating was designed to give a hydrophobic property on its surface by modifying it with hydroxyl terminated polydimethylsiloxane and then effects of surface hydrophobic tendency, water transport behavior and hence corrosion protectiveness of the modified polyurethane coating were examined using FT-IR/ATR spectroscopy, contact angle measurement and electrochemical impedance test. As results, the surface of polyurethane coating was changed from hydrophilic to hydrophobic property due primarily to a phase separation tendency between polyurethane and modifier by the modification. The phase separation tendency is more appreciable when modified by polydimethylsiloxane with higher content. Water transport behavior of the modified polyurethane coating decreased more in that with higher hydrophobic surface property. The decrease in the impedance modulus ${\mid}Z{\mid}$ at low frequency region in immersion test for polyurethane coatings was associated with the water transport behavior and surface hydrophobic properties of modified polyurethane coatings. The corrosion protectiveness of the modified polyurethane coated carbon steel generally increased with an increase in the modifier content, confirming that corrosion protectiveness of the modified polyurethane coating is well agreed with its water transport behavior.

• Journal of Pharmaceutical Investigation
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• 제25권2호
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• pp.101-108
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• 1995

The surface of albumin microspheres could be modified with methotrexate (MTX) by using 1,3-dicyclohexylcarbodiimide (DCC). Surface-modified albumin microspheres entrapping no MTX (SAMS), free MTX (SAMSF) and MTX-bovine serum albumin (BSA) conjugates (SAMSC) were prepared. respectively, and their release characteristics were investigated in the presence of trypsin using a dissolution tester. The mean diameters of all the microspheres were $5{\sim}8\;{\mu}m$, and their shapes was small and uniform. MTX bound tn their surfaces was released slower than the entrapped free MTX, and laster than the entrapped MTX-BSA conjugates. Also, surface-modified MTX was scarcely released in the absence of a proteolytic enzyme. Therefore, the surface-modified MTX may be released rapidly from SAMSC at the target site, and thereafter MTX may be released slowly from the encapsulated MTX-BSA conjugates in SAMSC for a long period.

• 전기학회논문지
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• 제63권8호
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• pp.1128-1133
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• 2014

Most of the statistical signal analysis processed in the time domain and the frequency domain are based on the assumption that the signal is weakly stationary(wide sense stationary). Therefore, it is necessary to know whether the surface EMG signals processed in the statistical basis satisfy the condition of the weak stationarity. The purpose of this study is to find optimal segment length of surface EMG signal for assessing stationarity with the modified Run-test and RA-test. Ten stationary surface EMG signals were simulated by AR(autoregressive) modeling, and ten real surface EMG signals were recorded from biceps brachii muscle and then modified to have non-stationary structures. In condition of varying segment length from 20ms to 100ms, stationarity of the signals was tested by using six different methods of modified Run-test and RA-test. The results indicate that the optimal segment length for the surface EMG is 30ms~35ms, and the best way for assessing surface EMG signal stationarity is the modified Run-test (Run2) method using this optimal length.

• 한국환경보건학회지
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• 제45권6호
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• pp.561-568
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• 2019

Objectives: The most commonly detected heavy metals in rocks and soils, including Pb, Cd, Cu, Fe, Mn and As, are representative pollutants discharged from abandoned mines and have been listed as potential sources of contamination in drinking water. This study focused on increasing the removal efficiency of heavy metals from drinking water resources by surface modification of natural adsorbents to reduce potential health risks. Methods: Iron oxide coating and graft polymerization with zeolites and talc was conducted for bipolar surface modification to increase the combining capacity of heavy metals for their removal from water. The removal efficiency of heavy metals was measured before and after the surface modification. Results: The removal efficiency of Pb, Cu, and Cd by surface modified zeolite showed 100, 92, and 61.5%, respectively, increases compared to 64, 64, and 38% for non-modified zeolite. This implies that bipolar surface modified natural adsorbents have a good potential use in heavy metal removal. The more interesting finding is the removal increase for As, which has both cation and anion characteristics showing 27% removal efficiency where as non-modified zeolite showed only 2% removal. Conclusions: Zeolite is one of the most widely used adsorptive materials in water treatment processes and bipolar surface modification of zeolite increases its applicability in the removal of heavy metals, especially As.

• 호남수학학술지
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• 제43권3호
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• pp.453-463
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• 2021

In this study, tubular surfaces that play an important role in technological designs in various branches are examined for the case of the base curve is not satisfying the fundamental theorem of the differential geometry. In order to give an alternative perspective to the researches on tubular surfaces, the modified orthogonal frame is used in this study. Firstly, the relationships between the Serret-Frenet frame and the modified orthogonal frame are summarized. Then the definitions of the tubular surfaces, some theorems, and results are given. Moreover, the fundamental forms, the mean curvature, and the Gaussian curvature of the tubular surface are calculated according to the modified orthogonal frame. Finally, the properties of parameter curves of the tubular surface with modified orthogonal frame are expressed and the tubular surface is drawn according to the Frenet frame and the modified orthogonal frame.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.360-362
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• 2003

The adhesion of hydrocarbon degrading bacteria(HDB) differing in surface hydrophobicity was investigated. Cell wall hydrophobicity was modified chemically and physiologically. Modified adhesion deficient mutant of HDB was selected in a soil column assay Physiologically and chemical modification increased cell surface hydrophobicity. Cell surface charcteristis including BATH and zeta potential were measured. Physiological modification using ampicillin was not stable, but chemical modification was stabel. Hydrocarbon degrading potential was measured for modified and unmodifed HDB.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.273-276
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• 2004

The adhesion of hydrocarbon degrading bacteria(HDB) differing in surface hydrophobicity was investigated. Cell wall hydrophobicity was modified chemically and physiologically. Modified adhesion deficient mutant of HDB was selected in a soil column assay. Physiologically and chemical modification increased cell surface hydrophobicity. Cell surface characteristics including BATH and FTIR were measured. Physiological modification using ampicillin was not stable, but chemical modification was stable. Hydrocarbon degrading efficiency was measured of TPH modified and unmodifed HDB.

• 한국주조공학회지
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• 제17권2호
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• pp.135-144
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• 1997

The relative machinability of the invar-type cast alloys, such as invar cast steel, invar-type cast iron, Meehanite cast iron, and the modified Invar-type cast iron containing Mo and V was evaluated based on the tool life test, the surface roughness test and the chipping test. Tool life and surface roughness were measured under various cutting conditions. The tool lives of Invar cast steel, Meehanite cast iron, the modified Invar cast iron and Invar cast iron was 12 min, 8 min, 1 min, 41 min, respectively. The surface finish of Invar cast steel and the modified Invar cast iron was better than that of Meehanite cast non, and the chip breakability of invar cast iron and Meehanite cast iron was better than that of invar cast steel. The Taylor's equations of invar cast steel and the modified invar cast iron were $VT^{0.3076}=154.479$ and $VT^{0.3880}=102.326$, respectively. As the cutting speed increases, the surface finish of the modified invar cast iron was improved.