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

Magnesium stress corrosion cracking

The service performance of magnesium alloy wheel hub was simulated by studying the effect of surface defect size on the corrosion resistance of a calcium phosphate conversion coated AZ80 magnesium alloy. The surface defects were produced with different sizes using a Film Impactor. The corrosion behaviour was studied using electrochemical, hydrogen evolution and immersion tests. The microstructures were characterized using a scanning electron microscope and a laser confocal microscope. Phases and the corrosion products were analyzed using XRD and XPS. The size of the surface defects influenced the corrosion resistance of the coating and the corrosion initiation area. The coating provided no protection for an indentation larger than 2.7 mm. The corrosion mechanism of the coating was also clarified.

Influence of indentation size on the corrosion behaviour of a phosphate conversion coated AZ80 magnesium alloy

The effect of B addition on the microstructure and mechanical properties of AM50 was investigated, and the mechanism of grain refinement was clarified. Optical microscopy, X-ray diffraction, scanning electron microscopy, and electron probe microanalysis were used to characterize the microstructure evolution. The grain size of as-cast AM50 decreased from 550 μm to 100 μm with the B content increasing from 0 to 0.15 wt.%. AlB₂ particles in the Al-3B master alloy transformed to Mg-B, and acted as the grain refiner. The addition of B to as cast AM50 alloy results in improved mechanical properties of AM50 + xB alloys. For instance, the YTS (yield tensile strength), UTS (ultimate tensile strength), and elongation of as cast AM50 + 0.15 wt.% B alloy was 94 MPa, 215 MPa, and 12.3%.

https://www.mdpi.com/1996-1944/12/7/1100/pdf

Effect of Boron on the Grain Refinement and Mechanical Properties of as-Cast Mg Alloy AM50

The properties of copper rich Cu-Fe-Cr alloys were characterized for the purpose of developing a new cost effective, high strength, high conductivity copper alloy. The copper rich corner of the ternary Cu-Fe-Cr phase diagram was determined using wavelength dispersive spectroscopy and resistivity measurements.

Cu-rich corner of the Cu-Fe-Cr phase diagram

Our recently developed plug-in specimens allow direct comparison between corrosion rates measured by weight loss, hydrogen evolution and from Tafel extrapolation of polarization curves. These have allowed identification of some of the reasons why Tafel extrapolation has previously not provided a good measure of steady state corrosion for Mg, because: (i) of crevice corrosion in the specimen mount, (ii) of decoupling of the Mg corrosion from the electrochemical measurements; and (iii) Tafel extrapolation has often been used to study Mg corrosion soon after specimen insertion into the solution, despite the fact that Mg alloy corrosion is often non-linear, the corrosion rate accelerates to a steady state rate after an initial period of low corrosion rate.

Andrej Atrens

Papers

Magnesium stress corrosion cracking

Influence of indentation size on the corrosion behaviour of a phosphate conversion coated AZ80 magnesium alloy

Effect of Boron on the Grain Refinement and Mechanical Properties of as-Cast Mg Alloy AM50

Cu-rich corner of the Cu-Fe-Cr phase diagram

Overview of the Mg Corrosion Mechanism