The effects of Quenching and Partitioning (Q&P) and Annealed Martensite (AM) heat treatment on the microstructure and tensile properties were investigated for 0.24C-0.5Si-1.5Mn-1Al steels. The Q&P steels were annealed at a single phase (γ) or a dual phase (γ+α), followed by quenching to a temperature between Ms and Mf. Then, enriching carbon was conducted to stabilize the austenite through the partitioning, followed by water quenching. The AM steels were intercritically annealed at a dual phase (γ+α) temperature and austempered at Ms and Ms±50˚C, followed by cooling in oil quenching. The dual phase Q&P steels showed lower tensile strength and yieldyield strength than those of the single phase Q&P steels, and tThe elongation for the dual phase Q&P steel was partitioning 100s higher than that of that for the single phase Q&P steels as the partitioning time was less than 100s up to partitioning 100s. For AM steels, the tensile/yield strength decreased and the total elongation increased as the austempering temperature increased. The stability of the retained austenite controlled the elongation for Q&P steels and the volume fraction of the retained austenite controlled the elongation for AM steels.

This study was undertaken to assess tear volume and stability in contaet lens wearers. Thirty-four young subjects(mean age 23. 79±3.1 years, 8 men and 26 women) without overt oeular disease were reeruited and eategorized into two groups based on eontact lens wear(soft lens, RGP lens). Measures from both eyes were made using a Sehirmer test, phenol red thread(PRT) and tear break time(tBUT) before eontaet lens wear, and at the time of 1 week, 1month and 3 month after lens wear. For the eomplete group of subjeets, the average Sehirmer wetting length was 13.76±8.34 mm, the average PRT wetting length was 17.42±6.26 mm and the tBUT averaged 4.77±2.69 see. The intereye differenees averaged 2.62±3.54 mm for Sehirmer test, 3.91±4.12 mm for PRT and 0.80±0.62 see for tBUT. Compared with the eontrol group the Sehirmer data showed a trend to be inereased at the first week but it reeovered after 1 month of RGP lens wear. After 3 months of RGP lens wear, the PRT and tBUT data showed a trend to be deereased to 27% and 21% respeetively. In the soft lens group, all the tear measures did not show any differenees at the first week eompared with the eontrol group. But after 3 months of soft lens wear, the Sehirmer and PRT data showed a trend to be deereased to 13% and 17% respeetively. As a result, wearing eontaet lenses seems to ehange the tear volume and stability. RGP lens seems to stimulate the reflex tearing but deerease the lower meniseus tear volume and tear stability, and soft lens seems not to influenee the tear film but to deerease the reflex tearing and lower meniseus tear volume.

As the amount of slag generated annually increases, attempts to recycle slag as high value products are underway in order to develop an efficient resource recycling industry based on slag and derive economic benefits as well. However, the application of electric arc furnace (EOS) slag as construction material is practically limited because of the unstable substances included in it, such as free CaO.(EOS contains a small amount of free CaO, but several limitations still exist. Slag is stored for more than 3 months depending on the quantity of slag, which leads to additional economic loss. In this study, the amount of free CaO present in EOS is quantitatively evaluated to examine its qualities as a potential construction material and verify its application as concrete material. The quantitative analysis of free CaO present in EOS is performed using ethylene glycol. The free CaO contents of EOS samples were found to be below 0.5%. This satisfies the criteria specified in KS F 4571, which states that the CaO content should be below 40% and CaO/SiO2 ratio should be below 2.0. In addition, it was confirmed that free CaO content difference appears to be dependent on the aging period and storage position.

Replacement aggregate source like as electric arc furnace slag will be important more and more in the domestic construction field. Recently KS F 4715 was revised in order to utilize electric arc furnace slag as concrete aggregate. However, stability for an actual structure has not been confirmed sufficiently. Therefore, more careful attention should be paid on the quality management of slag aggregate. To evaluate the volume stability of electric arc furnace slag, a method of immersion expansion for evaluating road aggregate has been used. These conventional method needs long time, so there are many demands from industry for fast testing method. This paper is intended to evaluate whether the acceleration test method in the hydro thermal condition is proper or not, and find the correlations between the volume expansion and oxide compounds of slag aggregate. The test results indicates that the acceleration test method has sufficient possibility as a way of evaluating the safety of electric arc furnace slag, and that there is no correlations between the volume expansion of mortar bar with slag aggregate and the oxide compositions of slag aggregate, but the main cause of the pop-out phenomenon is the MgO content of slag aggregate.