다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

There is a special reason for reviewing this book at this time: it is the 50th edition of a compendium that is known and used frequently in most chemical and physical laboratories in many parts of the world. Surely, a publication that has been published for 56 years, withstanding the vagaries of science in this century, must have had something to offer. There is another reason: while the book is a standard fixture in most chemical and physical laboratories, including those in medical centers, it is not as frequently seen in the laboratories of physician's offices (those either in solo or group practice). I believe that the Handbook can be useful in those laboratories. One of the reasons, among others, is that the various basic items of information it offers may be helpful in new tests, either physical or chemical, which are continuously being published. The basic information may relate

Handbook of Chemistry and Physics

Biodegradable metals are breaking the current paradigm in biomaterial science to develop only corrosion resistant metals. In particular, metals which consist of trace elements existing in the human body are promising candidates for temporary implant materials. These implants would be temporarily needed to provide mechanical support during the healing process of the injured or pathological tissue. Magnesium and its alloys have been investigated recently by many authors as a suitable biodegradable biomaterial. In this investigative review we would like to summarize the latest achievements and comment on the selection and use, test methods and the approaches to develop and produce magnesium alloys that are intended to perform clinically with an appropriate host response.

/pdf/degradable-biomaterials-based-on-magnesium-corrosion-4sw919tlb2.pdf

Degradable biomaterials based on magnesium corrosion

https://material.karlov.mff.cuni.cz/people/janecek/studenti/FyzMetNano/Estrin_AM61_2013_782.pdf

Extreme grain refinement by severe plastic deformation: A wealth of challenging science

The objective of this study is to review and evaluate the applications of magnesium in the automotive industry that can significantly contribute to greater fuel economy and environmental conservation. In the study, the current advantages, limitations, technological barriers and future prospects of Mg alloys in the automotive industry are given. The usage of magnesium in automotive applications is also assessed for the impact on environmental conservation. Recent developments in coating and alloying of Mg improved the creep and corrosion resistance properties of magnesium alloys for elevated temperature and corrosive environments. The results of the study conclude that reasonable prices and improved properties of Mg and its alloys will lead to massive use of magnesium. Compared to using alternative materials, using Mg alloys results in a 22% to 70% weight reduction. Lastly, the use of magnesium in automotive components is increasing as knowledge of forming processes of Mg alloys increases.

Magnesium and its alloys applications in automotive industry

Hydrogen Mobility in a Ni-Base Alloy

This paper studied the electrical resistivity of in situ Cu-Fe microcomposites using theoretical analysis and experiments. The model alloys Cu-XFe (X = 3, 4.3, 11, 14 and 17 wt.%) were produced by casting, and the microcomposites were prepared by thermomechanical treatment. The solid solubility of iron in the copper matrix was measured using an energy dispersive spectrometer. The electrical resistivity and conductivity was evaluated using a micro-ohmmeter. The conductivity of the Cu-XFe (X = 3 and 4.3) was essentially constant at ~ 40% IACS. The conductivity of the Cu-XFe (X = 11, 14, 17) microcomposites decreased in a nonlinear manner with increasing iron content and increasing cold deformation strain, which was mainly determined by the interface scattering resistivity caused by the interface between the copper matrix and the iron fibers.

Microstructure and Electrical Resistivity of In Situ Cu-Fe Microcomposites

Mg-Zn-Y alloys solidified under high pressure were characterized using XRD, DTA, SEM, and TEM. After solidification at atmospheric pressure, Mg-6Zn-1Y consisted of α-Mg, Mg7Zn3, and Mg3YZn6, while Mg-6Zn-3Y consisted of α-Mg, Mg3Y2Zn3, and Mg3YZn6. After solidification at 6 GPa pressure, both alloys consisted of α-Mg, MgZn, and Mg12YZn. The size and the shape of the second-phase particles formed for atmospheric solidification were significantly different to those formed for solidification at 6 GPa pressure. In Mg-6Zn-1Y, the second-phase size decreased from 300 to 50 nm, and the shape changed from needle like to blocky. In Mg-6Zn-3Y, the size decreased from 100 to 50 nm and the shape changed from short rod like to small and round. After aging at 200 °C for 12 h, the new MgZn phase transformed into the intermediate MgZn2 phase. Increasing the aging time to 24 h caused the intermediate MgZn2 phase to transform into Mg7Zn3 with a size of 50 nm, while the Mg12YZn phase remained unchanged.

Solidification of Mg-Zn-Y Alloys at 6 GPa Pressure: Nanostructure, Phases Formed, and Their Stability

Primary Creep and Stress-Corrosion Cracking

Corrosion of Mg-Y alloys was studied using electrochemical evaluations, immersion tests and direct observations. There were two important effects. In 0.1 M NaCl, the corrosion rate increased with increasing Y content due to increasing amounts of the Y-containing intermetallic. In 0.1 M Na SO , the corrosion rate decreased with increasing Y content above 3%, attributed to a more protective surface film, despite the intermetallic. The corrosion rate evaluated by electrochemical impedance spectroscopy was somewhat smaller than that evaluated from H evolution as expected from the Mg corrosion mechanism.

Andrej Atrens

Papers

Hydrogen Mobility in a Ni-Base Alloy

Microstructure and Electrical Resistivity of In Situ Cu-Fe Microcomposites

Solidification of Mg-Zn-Y Alloys at 6 GPa Pressure: Nanostructure, Phases Formed, and Their Stability

Primary Creep and Stress-Corrosion Cracking

Corrosion of magnesium-yttrium alloys