The Pythagorean hodograph (PH) curves are polynomial parametric curves whose hodograph (derivative) components satisfy the Pythagorean condition. Lots of research works had been done with PH curves relevant topics due that PH curves own many remarkable properties, e.g., its offset curves have exact rational representations. In this paper, ball curves with rational polynomial offset are studied....

Alkyl-terminated silicon nanoparticles (SiNPs) were prepared through reactive high-energy ball milling with contamination of iron from the steel milling materials. Iron impurities in the form of iron nanoparticles cause a decrease of photoluminescence intensity and an increase of the UV absorption. The iron impurities were removed either by gel permeation chromatography separation or by treatme...

Selective laser melting (SLM) technology has strict demand to its powder materials which is needed be spread evenly and conducted sintering layer by layer. Therefore, the uniformity flatness of bed are basic conditions for processing. Ball milling an important composite preparation process SLM. Three kinds ball processes, dry milling, wet hollow with various parameters adopted prepare TC4 / TiB...

although cu and fe are immiscible under equilibrium conditions, they can form supersaturated solid solutions by mechanical alloying. in this paper, nano-structured of the metastable cu-fe phase containing 10, 15, 20 and 25% wt fe were synthesized by intensive ball milling for 15h, in order to achieve a solid solution of fe in cu. the phase composition, dissolution of the fe atoms into the cu ma...

In this work, iron-doped SnO2 powders were prepared by two methods: mechanical alloying and mechanochemical alloying with successive thermal treatment. The influence of different milling conditions such as ball to powder weight ratio, milling time, rotation velocity of supporting disc and the type of iron starting reactive and their Fe concentration on the structural and magnetic properties of ...

The use of mechanochemistry to carry out enantioselective reactions has been explored in the last ten years with excellent results. Several chiral organocatalysts and even enzymes have proved to be resistant to milling conditions, which allows for rather efficient enantioselective transformations under ball-milling conditions. The present article reports the first example of a liquid-assisted g...

We provide the first in situ and real-time study of the effect of milling frequency on the course of a mechanochemical organic reaction conducted using a vibratory shaker (mixer) ball mill. The use of in situ Raman spectroscopy for real-time monitoring of the mechanochemical synthesis of a 2,3-diphenylquinoxaline derivative revealed a pronounced dependence of chemical reactivity on small variat...

Hydroxyapatite (HA) is the most important bioactive ceramics because of biocompatibility and structural similarity to the mineral part of bones and teeth of broad clinical application in the field of dentistry, orthopedic and coatings are Biomaterials. The aim of this study was to construct nano-hydroxyapatite micro particles using calcite, silica and zinc oxide using ball milling, powder, thes...

Nanocrystalline magnesium hydride powder was synthesized by mechanical milling of MgH2 in a planetary ball mill for various times. The effect of MgH2 structure, i.e. crystallite size, lattice strain, particle size and specific surface area on the hydrogen desorption properties was investigated. A single peak of hydrogen desorption was observed for as-received powder, exhibiting an average parti...

In the present work, the behavior of Cu-Cr powder mixtures during mechanical alloying has been studied. The powder mixtures with 1, 3 and 6 weight percents of Cr in Cu were treated. They were milled in a ball mill with two different speeds of 250 and 500 rpm using equal numbers of 1 and 2 centimeters balls. The weight ratio of balls to powders was 10 to 1 under argon atmosphere. Ethanol was use...