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This study evaluated the effectiveness of antioxidants in animal models with damaged lungs such as inflammatory mediator-induced acute respiratory distress syndrome (ARDS) and established an ARDS therapy technique by suppressing active oxygen with membrane oxygenator. When inflammatory mediator that has an endotoxin, such as LPS, was injected directly into the airway, inflammatory pulmonary edema developed in the lung, and could induce ARDS. To treat such endotoxin-induced ARDS, the antioxidants such as taurine and dexamethasone were injected and their antioxidant effects were evaluated. They turned the blood pH to the normal condition, increased blood hemoglobin and hemocrit concentration and oxygen partial pressure (PO2), and improved survival. When a membrane oxygenator was used alone on the animal models with ARDS, similar antioxidant effects were identified. When a membrane oxygenator and antioxidants were used simultaneously, synergistic antioxidant effects were revealed. Therefore, the simultaneous use of antioxidants and membrane oxygenator is more effective than the use of either of them in treating the animal models with ARDS. This result indicates that bilateral use of antioxidants and membrane oxygenator may be useful as a potential therapy technique for the treatment of acute respiratory distress syndrome.

The objective of this study was to scrutinize the involvement of nitric oxide (NO) and the diagnosis of blood in ARDS in a rat model determined by the sequential exposure to lipopolysaccharide (LPS). Also, the present study was designed to evaluate the effects of taurine and dexamethasone on ARDS induced by LPS. Measurements of nitrite/nitrate were elevated in BAL of LPS challenged rats, indicative of an induction of the NO synthase. Taurine and dexamethasone abrogated the extent of endotoxin-induced ARDS, as evidenced by the decreases BAL nitrate/nitrite, BALF protein and lung pathology. T+L+D-group had higher PaO2 and lower PaCO2 values than L-group and T+Lgroup. But, ionized Ca2+ and Mg2+ both were not shown significant change. Also, T+L and T+L+D-group showed significant increase compared with L-group, but for the other side no significant difference was seen between T+L and T+L+D group. We suggest that taurine and dexamethasone may be a drug of choice for preventing ARDS.

Use of Al alloy in the shipping industry has been increased due to various advantages such as high speed by lightness, increased load capacity by high strength and environmental-friendly compared with fiber-reinforced plastic (FRP) material. The welding of Al alloys have been conducted with MIG or TIG welding. However, the strength decrease by heat, become a serious problem in the process of ship construction. It can cause the deterioration of corrosion resistance at the heat-affected zone (HAZ) and the decrease in mechanical properties. The mechanical properties of dissimilar Al alloys (5052-O: 5083-H321) by FSW under various parameters such as rotating speed, traveling speed and the location of materials. First of all, the welding is conducted to find optimum FSW condition for dissimilar Al alloy with various parameters.

The structural steel demands are surging by the industry development. Among them, the demands of stainless steel has excellent anti-corrosion properties are expanding to various fields including the ship, offshore structure, petrochemical industry and living appliance. The stainless steel has some advantages that can change the property due to add chemical elements, various heat treatments and processing. However, in the STS 304, which makes up the majority of demands currently, involves a lot of risks the possibility of occurring stress corrosion cracking and hydrogen embrittlement of marine structure exposed to external forces and lower corrosion protection properties as destruction of passive layer in chloride environment. In this paper, we discuss the results of our investigations using potentiostatic slow strain rate test to estimate the durability of STS 304 against stress corrosion cracking (SCC) and hydrogen embrittlement (HE) under corrosive conditions of chloride ion exposure and tensile stress applied from external force. The optimum corrosion protection range without stress corrosion cracking and hydrogen embrittlement was concluded with the potential range of −0.5 ∼ −0.2 V (vs. Ag/AgCl).

Recent developments in high-technology experimental equipment and semiconductor micro fabrication technology have made it possible to study various characteristic quantum phenomena such as quantized conductance and coulomb-blockade effects at the nano-scale level. One recent study attempted to fabricate a normal-super-normal double tunneling junction in a split-gate wire. In this study, we describe the results of transmission electron microscopy (TEM) observation of a single 100 nm wide and 200 nm high Ni dot, which had been fabricated using scanning tunneling microscopy (SEM), placed on the top of the bridge of a Si-doped GaAs epitaxial layer grown by molecular beam epitaxy using a Riber 32 apparatus. The results from the successful use of TEM to observe the results of a SEM fabrication procedure support the contention that the fabricated Ni dot became a poly-crystal that was amorphous between GaAs crystal and a surface dot fabricated by applying voltage pulse to a STM tip, covered by an oxygenated film approximately 20 nm thick.

The purpose of this study was to investigate the effect of multiple mechanical forces in gas exchange and hemolysis in an intravascular lung assist device (IVLAD). Specific focus was given to the effect of membrane vibration. We designed the oscillatory type artificial lung assist device attached with a polyvinylidene fluoride sensor and a lead zirconate titanate (PZT) actuator (vibrator). Maximum oxygen transfer occurred at a frequency of 7 Hz for bovine blood and 35 Hz for distilled water. The normalized index of hemolysis oxygenator values for the circuit was 0.0014 g/mL for excitation of the PZT actuator with a sinusoidal 10-V wave and 0.0018 g/mL for a 50-V wave. The experiment results indicate effective performance in enhancing the gas transfer of the IVLAD. This novel hollow membrane filter IVLAD design demonstrates an acceptable level of gas exchange performance with an acceptable level of blood compatibility, and so it has potential as an implantable lung assist device for patients with acute respiratory distress syndrome.

We investigated the mechanical and electrochemical properties of aluminum alloys. Aluminum alloys do not corrode due to the formation of an anti-corrosive passive film, such as Al2O3 or Al2O3·3H2O, which resists corrosion in neutral solutions. In seawater, however, Cl − ions destroy this passive film. The current density in the first passivity range during the application of anodic protection had a similar value as that for concentration polarization by dissolved oxygen during the application of cathodic protection. The current density in the first passivity range had the lowest value overall. The lowest current densities in the potentiostatic and galvanostatic tests occurred at potentials of −1.4 to −0.7 V and −0.9 to −0.7 V, respectively.

Atomic force microscopy (AFM) has become an attractive technique to fabricate nano devices since the observing mechanism is different from fabricating one. We have fabricated the superconducting flux flow transistor (SFFT) with a serial-channel structure using the AFM lithography analyzed the modified surface by the AFM image. We investigated the induced voltage in a serial-channel terminals dependence on the gate current by the I–V measurement system. We performed the numerical simulation to get the theoretical characteristics of the SFFT controlled by the gate current via the modified channel. The transresistance was 0.006 Ω for Id=51 mA at Ig=5 mA. It is very low transresistance in comparison with SFFTs fabricated by the other processes, however our results show that the SFFT with a serial-channel structure is effectively fabricated by an AFM lithography method.

We report on the optimum corrosion protection potential range for stress corrosion cracking and hydrogen embrittlement of 5083-H112 Al alloy specimens using electrochemical methods and slow strain rate testing (SSRT) in seawater. In the results of the cathodic polarization curve, the concentration polarization due to dissolved oxygen reduction reaction correspondeds to a protection potential of OCP≈ −1.55 V. However, a potential of −1.2 V in the SSRT showed little effect of atomic hydrogen evolution. Potentials less than −1.6 V are affected by atomic and molecular hydrogen. We thus concluded that the effect of atomic hydrogen predominates. Overall, the optimum corrosion protection range for SCC and hydrogen embrittlement of 5083-H112 seems to be between −0.9 V and −0.7 V.

Recently, there has been increased interest in using aluminum alloys in ship construction instead of fiber-reinforced plastic (FRP). Aluminum alloy ships are faster, have a greater load capacity, and are easier to recycle than FRP ships. We investigated the mechanical and electrochemical properties of aluminum alloys using slow strain rate and potentiostatic tests under various potential conditions. Aluminum and aluminum alloys do not corrode due to the formation of an anti-corrosive passive film, such as Al2O3 or Al2O3·3H2O, which resists corrosion in neutral solutions. In seawater, however, Cl− ions destroy this passive film. The optimum protection potential range with regards to hydrogen embrittlement and stress corrosion cracking was determined to lie between −1.5 and −0.7 V (SSCE). These results can be used as reference data for ship design.

A series of electrochemical experiments on Al alloys were undertaken to determine their optimum protection potentials in seawater. With 1050 and 5456 alloys, passive films form during anodic polarization but are destroyed by the Cl in seawater, only to regrow as a result of the self-healing capacity of aluminum. The current density of 5456 Al alloy proved to be lower than that of 1050 as a whole. Any shift to more anodic or cathodic conditions in the potential range of-1.5∼-0.68 V resulted in a sudden increase in current density. Current densities in the high-strength 7075 Al alloy showed the greatest values. In contrast, the current densities of 5456 alloy, known to have excellent corrosion resistance in seawater, were the lowest in the range of -0.70∼-1.3 V, and we concluded that this potential range offered optimal protection.

The purpose of this study was to assess and quantify the beneficial effects of gas exchange according to the various frequencies of the sinusoidal wave that are excited by a PZT actuator, on patients suffering from acute respiratory distress syndrome (ARDS). In this study, an experimental method for the flow hydrodynamics was developed through a bundle of sinusoidally vibrated hollow fibers to observe how well vibrations might enhance the performance of the VIVLAD. We measured the effect of the various excitation frequencies of the PZT actuator on the gas transfer rates and hemolysis from the maximum gas transfer rate. As a result, the maximum oxygen transfer rate was reached at the maximum amplitude and through the transfer of vibrations to the hollow fiber membranes. The device was maximum excited by a frequency band of 7 Hz at various water flow rates, as this frequency was the 2nd mode resonance frequency of the flexible beam. 675 hollow fiber membranes were also bundled, within the blood flow, into the device.

Electrochemical properties and mechanical properties of welded high strength steel were investigated by the slow strain rate test (SSRT) method with an applied constant cathodic potential. There was no correlation between maximum tensile strength, yield strength, stress at failure, and hydrogen embrittlement. However, the elongation, time-to-fracture, and strain-to-failure ratio decreased with shifting potential of the negative direction. Elongation, time-to-fracture, and strain-to-failure ratio for the various welding methods displayed the highest values when the potential was −770 mV regardless of post-weld heat treatment (PWHT) conditions. The elongation, time-to-fracture, and amount of dimples by PWHT were increased. The optimum potential region for cathodic protection without hydrogen embrittlement was observed between −770 and (above) −850 mV (SCE) in the post-weld specimens heat treated at 550°C and the as-welded specimens.

Mg alloys were anodized in alkaline NaOH solutions with various additives as a non-chromate method. Specimen AZ91 was anodized at a potential that produced a strong surface dissolution reaction and generated a large amount of Mg(OH)2. The effect of sealing after anodizing was investigated, focusing on the effects of sealing time, temperature and solution conditions. The current density decreased with increasing A1(OH)3 concentration in 1 M NaOH solution during anodizing; sparking occurred at potentials above 80 V. The best corrosion resistance with anodizing in 1 M NaOH solution occurred at a potential of 4 V, which caused the strongest active dissolution reaction. The sealing effect improved with increasing time and temperature, and corrosion resistance was proportional to the relative ratio of Mg(OH)2. If the oxygen thickness observed by EDX equaled the film thickness, the film formed at 4 V in 1 M NaOH was 10–15 Μm thickness. The optimum corrosion resistance in sealing at various solutions after anodizing was 1M-NaOH solution.

The state in which a stainless steel (STS) exhibits a very low corrosion rate is known as passivity, which is self-healing in a wide variety of environments. However, for those STS the corrosion includes pitting, crevice corrosion, galvanic corrosion, hydrogen embrittlement and stress corrosion cracking etc. And the corrosion resistance of STS is affected by area ratio, solution temperature and solution condition etc. Corrosion characteristics of STS 304, welding parts STS 316, STS 329 and STS 444 were investigated with parameters such as corrosion potential, galvanic current measurements, cathodic and anodic polarization behaviors as a function of area ratio and solution temperature in solution for hot water tank. It was found that galvanic current is affected by the area ratio, temperature and a kind of STS for hot water tank. Corrosion potential of welding part STS 316 was lower than that of STS 304, STS 329, STS 444 in solution for #1, #2 hot water tank. Therefore, it is suggested that the welding part STS 316 acts as anode for the other STSs. The amplitude of galvanic current between welding parts STS 316 and STS 304, STS 329, STS 444 in #1 solution is smaller than that in #2 solution. This is the reason that chloride ion quantity in #2 solution is more than that for #1 solution. And then welding part STS 316 corrodes easily by acting as anode compared to the other STS.

Impressed current cathodic protection can result in hydrogen embrittlement, which can cause trouble with high-strength steels, particularly at welds. Therefore, the limiting potential for hydrogen embrittlement should be examined in detail as a function of the cathodic protection potential. This study investigated the effects of post-weld heat treatment (PWHT) on marine structural steels from an electrochemical viewpoint. In addition, the slow strain rate test (SSRT) was used to investigate both the electrochemical and mechanical effects of PWHT on impressed current cathodic protection. According to the SSRT, the optimum cathodic protection potential was −770 mV [with a saturated calomel electrode (SCE)]. SEM fractography analysis showed that the fracture morphology at an applied cathodic protection potential of −770–850 mV (SCE) was a dimpled pattern with ductile fractures, while a transgranular pattern was seen at potentials below −875 mV (SCE). Therefore, the cathodic protection potential range should be −770–850 mV (SCE).

Chemical conversion treatment of Mg−Al alloy (AZ91) using colloidal silica as an alternative to chromate conversion was investigated as a function of solution pH, temperature, solution conditions, and treatment time. The solution used for the colloidal silica coating consisted of colloidal silica, titanium sulfate, and cobalt ions to maintain good anti-corrosion and adhesion properties. Adding CoSO4 to the colloidal silica solution enhanced the adhesion force between the silica film and magnesium substrate. The optimum conditions for the chemical conversion treatment solution were pH 2, 90-sec treatment, and 25°C.

The cathodic protection method is being widely used in marine structural steel. However, a high tensile steel such as RE 36 steel used for marine structural steel is easily susceptible to hydrogen embrittlement due to overprotection as well as the preferential corrosion of the heat affected zone (HAZ). In this paper, corrosion resistance and mechanical properties were investigated from the electrochemical view and mechanical view in as-wedded and post-weld heat treated specimens. Fracture surface was analyzed by SEM. The corrosion resistance in post-weld heat treated at 550°C was superior to that at other post-weld heat treatment (PWHT) temperature. On the other hand, elongation was decreased with a shift to the low potential direction which may cause hydrogen embrittlement. And a quasi-cleavage (Q.C) fracture mode was also observed significantly with a potential increase to the active direction.

Corrosion resistance, mechanical properties and hydrogen embrittlement were investigated from an electrochemical view, with the slow strain rate test (SSRT) method with applied constant cathodic potential. Fracture surface was analyzed by SEM. Corrosion resistance and mechanical properties were increased by post-weld heat treatment (PWHT) compared to those in the as-welded condition. Elongation and time-to-fracture were decreased with shifting cathodic polarization potential to the low potential direction. On analysis of SEM fractography, the quasi-cleavage (Q.C) fracture mode was also observed with an increase of susceptibility to hydrogen embrittlement. At the applied cathodic potential between −770 mV and −875 mV (SCE; saturated calomel electrode), the fracture morphology was of the dimple pattern with ductile fracture, while it changed to the transgranular pattern at under −900 mV (SCE). Eventually it is suggested that an optimum cathodic protection potential range was from −770 mV to −875 mV (SCE) without regard to PWHT condition.