The dynamics of laser melting of atomically clean Si is investigated in ultra-high-vacuum (UHV) by transient reflectivity with single-pulse sensitivity in the presence of monitored amounts of chlorine, oxygen or propene. Adsorption of one monolayer (1 ML) leads to measurable variations of the melting dynamics, which are strongly adsorbate-dependent. The variations differ qualitatively and quant...

For biodegradable polymers such as poly (Llactic acid) (PLLA), material crystallinity has a considerable effect on degradation and physical properties. In this work, the effects of laser fluence of a 355 nm UV Q-switched Nd-YAG laser on the crystallinity and conformation at the surface of PLLA films and the factors affecting the transformation are investigated. Electron microscopy, X-ray diffra...

Recently, high-performance lightweight materials with outstanding mechanical properties have opened up their way to some sophisticated industrial applications. As one of these systems, aluminum matrix composites/nanocomposites (AMCs) offer an outstanding combination of relative density, hardness, wear resistance, and mechanical strength. Until now, several additive manufacturing methods have be...

INTRODUCTION The aim of this study was to evaluate the effect of dental surface treatment with Erbium-Doped Yttrium Aluminum Garnet(Er: YAG), Neodymium-Doped Yttrium Aluminium Garnet(Nd: YAG) and Carbon Dioxide Laser (CO2) lasers and sodium ascorbate to recently home bleached enamel by scanning electron microscope (SEM). METHODS Thirty extracted human third molars were selected for this in vi...

Since the late eighties generative manufacturing methods have been established as manufacturing systems for the product development in various sectors of industries. After only used for the production of demonstration models (Rapid Prototyping) is the rapid tooling and manufacturing now able to service a steady increasing range of applications. In order to achieve this status the range of usabl...

Using bioresorbable materials implants can be manufactured which dissolve in the human body and are replaced by natural bone structure. For large implants an interconnecting porous structure needs to be integrated in the implant for a good vascularisation. Using additive manufacturing technology these internal structures can be directly manufactured. The structure can be designed by consequent ...

A new method for improving the efficiency of laser drilling has been developed. Two synchronized free-running laser pulses from a tandem-head Nd:YAG laser are capable of drilling through 1/8-in-thick stainless-steel targets at a standoff distance of 1 m without gas-assist. The combination of a high-energy laser pulse for melting with a properly tailored high-intensity laser pulse for liquid exp...

introduction: the main purpose of the present study was to describe the ultra structural changes which happened after treatment of the root surfaces with ultrasonic and hand devices followed by erbium-doped yttrium aluminum garnet (er:yag) laser irradiation. methods: sixty single-rooted maxillary and mandibular teeth which had been extracted due to periodontal problems were collected. crown and...

Temperature, thermal history, and dynamics of Earth rely critically on the knowledge of the melting temperature of iron at the pressure conditions of the inner core boundary (ICB) where the geotherm crosses the melting curve. The literature on this subject is overwhelming, and no consensus has been reached, with a very large disagreement of the order of 2,000 K for the ICB temperature. Here we ...

Excimer laser ablation of gold films deposited on a quartz crystal microbalance is investigated. The ablation rate is directly obtained from the frequency shift of the microbalance. The measured single-shot ablation rate is found to be at least two orders of magnitude higher than the numerical predictions based on a surface vaporization model. Surface morphologystudies indicate that hydrodynami...