• Bulletin of the Korean Chemical Society
• /
• v.30 no.7
• /
• pp.1637-1640
• /
• 2009

• Bulletin of the Korean Chemical Society
• /
• v.20 no.9
• /
• pp.999-1004
• /
• 1999

Two compact sized globular proteins, β-lactoglobulin and α-lactalbumin were kinetically characterized at the aqueous solution surface with the measurement of surface pressure (π) and surface concentration (Γ) via a radiotracer method. The adsorption kinetics was of diffusion control at early times, the rates of increase of πand Γ being lower at longer times due to growing energy barrier. At low concentrations, an apparent time lag was observed in the evolution of π for β-lactoglobulin but not for α-lactalbumin which was shown to be due to the non-linear nature of the p- G relationship for the former. The area per molecule of an adsorbed β-lactoglobulin during adsorption was smaller than that for spread monolayer since β-lactoglobulin was not fully unfolded during the adsorption. For α-lactalbumin, however, no such difference in the molecular areas for adsorbed and spread monolayer was observed indicating thereby that α-lactalbumin unfolded much more rapidly (has looser tertiary structure) than β-lactoglobulin. Surface excess concentrations of α-lactalbumin was found to evolve in two steps possibly due to the change in the orientation of the adsorbed protein from a side-on to an end-on orientation.

• Journal of the Korean institute of surface engineering
• /
• v.15 no.1
• /
• pp.18-23
• /
• 1982

The microstructure of Watts and bright ni-ckel electrodepositss is correlated with pref-erred orientation. The characteristics lamellar structure of bright nickel was atributed to the periodic adsorption of organic additives and related to cyclic fluctuations in temper-ature.

• Journal of the Korean Chemical Society
• /
• v.53 no.4
• /
• pp.399-406
• /
• 2009

The fluorescence study was performed to see whether the adsorption orientation of 4-biphenyl acetonitrile(BPAN) on metal colloids can be changed by forming an inclusion complex with $\alpha$-cyclodextrin($\alpha$-CD). The fluorescence quenching was observed with increasing temperature to confirm the direct adsorption of BPAN to the Au and Ag colloidal surfaces. BPAN adsorbed on the metal colloids formed inclusion complex with $\alpha$-CD regardless of the kinds of metal colloids. The formation constants, 32 $M^{-1}$ and 13 $M^{-1}$ for Au and Ag colloids respectively, were obtained with Benesi-Hildebrand plot. The molecules adsorbed on both the Au and Ag colloidal surfaces behaved similarly to each other, leading to the conclusion that the orientation of BPAN adsorbed on the metal colloids can be modified with $\alpha$-CD.

• Clean Technology
• /
• v.28 no.3
• /
• pp.249-257
• /
• 2022

The adsorption equilibria of nitrogen on a region of nanoporous carbonaceous adsorbent with local molecular orientation (LMO) were calculated by grand canonical Monte Carlo simulation at 77.16 K. Regions of LMO of identical size were arranged on a regular lattice with uniform spacing. Microporosity was predominately introduced to the model by removing successive out-of-plane domains from the regions of LMO and tilting pores were generated by tilting the basic structure units. This pore structure is a more realistic model than slit-shaped pores for studying adsorption in nanoporous carbon adsorbents. Their porosities, surface areas, and pore size distributions according to constrained nonlinear optimization were also reported. The adsorption in slit shaped pores was also reported for reference. In the slit shaped pores, a clear hysteresis loop was observed in pores of greater than 5 times the nitrogen molecule size, and in capillary condensation and reverse condensation, evaporation occurred immediately at one pressure. In the LMO pore model, three series of local condensations at the basal slip plane, armchair slip plane and interconnected channel were observed during adsorption at pore sizes greater than about 6 times the nitrogen molecular size. In the hysteresis loop, on the other hand, evaporation occurred at one or two pressures during desorption.

• Journal of Advanced Marine Engineering and Technology
• /
• v.20 no.5
• /
• pp.103-113
• /
• 1996

The properties of the deposited film depend on the deposition condition and these, in turn depend critically on the morphology and crystal orientation of the films. Therefore, it is important to clarify the nucleation occurrence and growth stage of the morphology and orientation of the film affected by deposition parameters, e.g. the gas pressure and bias voltage etc. In this work, magnesium thin flims were prepared on cold-rolled steel substrates by a thermo-eletron activation ion plating technique. The influence of nitrogen gas pressure and substrate bias voltage on their crystal orientation and morphology of the coated films were investigated by scanning electron microscopy (SEM) and X-ray diffraction, respectively. The diffraction peaks of magnesium film became less sharp and broadened with the increase of nitrogen gas pressure. With an increase in nitrogen gas pressure, flim morphology changed from colum nar to granular structure, and surface crystal grain-size decreased. The morphology of films depended not only on gas pressure but also on bias voltage, i.e., the effect of increasing bias voltage was similar to that of decreasing gas pressure. The effect of crystal orientation and morphology of magnesium films on corrosion behaviors was estimated by measuring anodic polarization curves in deaerated 3%NaCl solution. Magnesium, in general, has not a good corrosion resistance in all environments. However, these magnesium films prepared by changing nitrogen gas pressure showed good corrosion resistance. Among the films, magnesium films which exhibited granular structure had the highest corrosion resistance. The above phenomena can be explained by applying the effects of adsorption, occlusion and ion sputter of nitrogen gas.

• Journal of the Korean Chemical Society
• /
• v.47 no.5
• /
• pp.439-446
• /
• 2003

Surface-enhanced Raman(SER) spectroscopy was utilized to investigate the adorption orientation of the 4-biphenylcarboxylic acid(BPCA) derivatives, such as 4'-cyano-BPCA(c-BPCA), 4'-mercapto-BPCA(m-BPCA), and 4'-amino-BPCA(a-BPCA), which were adsorbed on Au and Ag colloid monolayers. For the systematic approach, information regarding the adsorption behavior of benzoic acid, biphenyl, and BPCA was applied to the target molecules. From the spectral behaviors of benzene ring, C-H stretching, carboxylate anion, and the other finger printing vibrational modes, it was concluded that only the m-BPCA was adsorbed tilt with thiol group being adsorbed on Au surface, whereas the other molecules were adsorbed flat on both Au and Ag surfaces.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.8
• /
• pp.2553-2559
• /
• 2012

The adsorption properties of benzene, toluene, p-xylene in MCM-41 with heterogeneous and cylindrical pore were studied using grand canonical ensemble Monte Carlo simulation. The simulated isotherms were compared with experimental ones, and the different adsorption behaviors in MCM-41 with pore diameters of 2.2 and 3.2 nm were investigated. The simulated adsorption amounts above the capillary-condensation pressure agreed with the experimental ones. The simulation results showed that most molecular planes were nearly parallel to the pore axis. This orientation was not affected by the molecular position in the pore. The molecular planes were nearly parallel to the pore surface for the adsorbate molecules close to the pore wall, and the molecules in the MCM-41 with the pore diameter of 3.2 nm were ordered along the pore axis.

• Journal of the Korean Chemical Society
• /
• v.16 no.4
• /
• pp.208-213
• /
• 1972

Isostric heats of adsorption of amines on paraffin and polyethyleneglycol were measured by gas chromatography. Value with polyethyleneglycol were significantly higher than those with paraffin due to the N-H...O bonding. The contribution of C-H...O bonding to the isosoteric heats of adsorption was negligible. The additional heats of adsorption observed as the sample size increased also increased as the number of amino hydrogen atoms decreased. This tendency was more significant with polyethyleneglycol indicating that strong directing force of amino hydrogen of primary and secondary amines to the surface hinder lateral attractive interaction which could be favored with free orientation.

• Corrosion Science and Technology
• /
• v.3 no.4
• /
• pp.148-153
• /
• 2004

Magnesium thin flims were prepared on cold-rolled steel substrates by RF magnetron sputtering technique. The influence of argon gas pressure and substrate bias voltage on their crystal orientation and morphology of the coated films were investigated by scanning electron microscopy (SEM) and X-ray diffraction, respectively. And the effect of crystal orientation and morphology of magnesium films on corrosion behaviors was estimated by measuring anodic polarization curves in deaerated 3%NaCl solution. From the experimental results, all the sputtered magnesium films showed obviously good corrosion resistance to compare with 99.99% magnesium target of the sputter-evaporation metal. Finally it was shown that the Corrosion-resistance of magnesium films can be improved greatly by controlling the crystal orientation and morphology with effective use of the plasma sputtering technique.