PDMS residues-free micro/macrostructures on flexible substrates

Transfer printing has been reported recently as a viable route for electronics on flexible substrates. The method involves transferring micro-/macrostructures such as wires or ultra-thin chips from Si (silicon) wafers to the flexible substrates by using elastomeric transfer substrates such as poly(dimethylsiloxane) (PDMS). A major challenge in this process is posed by the residues of PDMS, which are left over on Si surface after the nanostructures have been transferred. As insulator, PDMS residues make it difficult to realize metal connections and hence pose challenge in the way of using nanostructures as the building blocks for active electronics. This paper presents a method for PDMS residues-free transfer of Si micro-/macrostructures to flexible substrates such as polyimide (PI). The PDMS residues are removed from Si surface by immersing the transferred structures in a solution of quaternary ammonium fluoride such as TBAF (Tetrabutylammonium Fluoride) and non-hydroxylic aprotic solvent such as PMA (propylene glycol methyl ether acetate). The residues are removed at a rate (∼1.5 μm/min) which is about five times faster than the traditional dry etch methods. Unlike traditional alternatives, the presented method removes PDMS without attacking the flexible PI substrates

Optical absorption parameters of amorphous carbon films from Forouhi–Bloomer and Tauc–Lorentz models: a comparative study

International audienceParametrization models of optical constants, namely Tauc-Lorentz (TL), Forouhi-Bloomer (FB) and modified FB models, were applied to the interband absorption of amorphous carbon films. The optical constants were determined by means of transmittance and reflectance measurements in the visible range. The studied films were prepared by rf sputtering and characterized for their chemical properties. The analytical models were also applied to other optical data published in the literature pertaining to films produced by various deposition techniques. The different approaches used to determine important physical parameters of the interband transition yielded different results. A figure-of-merit was introduced to check the applicability of the models and the results showed that FB modified for an energy dependence of the dipole matrix element adequately represents the interband transition in the amorphous carbons. Further, the modified FB model shows a relative superiority over the TL ones for concerning the determination of the band gap energy, as it is the only one to be validated by an independent, though indirect, gap measurement by x-ray photoelectron spectroscopy. Finally, the application of the modified FB model allowed us to establish some important correlations between film structure and optical absorption properties

Investigation of work function and chemical composition of thin films of borides and nitrides

Thin films of various borides, nitrides, and barium fluorides were tentatively deposited by pulsed laser deposition and by magnetron sputtering in order to develop the components of thermionic-photovoltaic devices for the high-temperature thermal to electrical conversion by solid state. To improve the device performance, the materials characterized by a low work function were selected. In the present work, the chemical composition and work function of obtained films were investigated by X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy techniques. The values of work function were determined from the cut-off in the He I valence band spectra. Different films were compared and estimated on the basis of X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy results

Intrinsic defects and their influence on the chemical and optical properties of TiO2x films

International audienceIn this work, TiO2 films produced by rf sputtering of a TiO2 target in argon and argon–oxygen plasmas were studied. The oxygen content in the feed gas was varied in a range 3–20%. The chemical composition and structure of films were characterized by Rutherford backscattering spectrometry, x-ray photoelectron spectroscopy (XPS) and x-ray diffraction. Important information about the intrinsic defects of the films and their effects on the optical properties as well as a scheme of the energy band structure of the films could be derived from a combined use of optical spectroscopy and XPS

Methodology of Supervision by Analysis of Thermal Flux for Thermal Conduction of a Batch Chemical Reactor Equipped with a Monofluid Heating/Cooling System

We present the thermal behavior of a batch reactor to jacket equipped with a monofluid heating/cooling system. Heating and cooling are provided respectively by an electrical resistance and two plate heat exchangers. The control of the temperature of the reaction is based on the supervision system. This strategy of management of the thermal devices is based on the usage of the thermal flux as manipulated variable. The modulation of the monofluid temperature by acting on the heating power or on the opening degrees of an air-to-open valve that delivers the monofluid to heat exchanger. The study shows that the application of this method for the conduct of the pilot reactor gives good results in simulation and that taking into account the dynamics of the various apparatuses greatly improves ride quality of conduct. In addition thermal control of an exothermic reaction (mononitration) shows that the consideration of heat generated in the model representation improve the results by elimination any overshooting of the set-point temperature

A marine thruster’s model identification based on experimental-simulation approach

In recent years, underwater vehicles play a very important role in the marine field, and tasks cannot be accomplished quickly and accurately without the use of such devices. Despite the progress achieved, these vehicles still have prob- lems with their controls in order to have a very good dynamic positioning or a path tracking accurately, and these problems have a direct link to their thrusters, either by negligence or by ignorance of its mathematical model. Several works were carried out to have an accurate model of them, but its behavior is still diffi- cult to be described and it strongly influences the behavior of a vehicle in which it is integrated. In this work we try to deal this problem in the aim to iden- tify a marine thruster designed by us using a low-cost test bench and a hybrid identification approach, which combines the both experimental and simulation parts. The thruster will be integrated on a remotely operated vehicle under devel- opment by AVCIS-Lab to make simulation using UUV (unmanned underwater vehicle) Simulator and ROS (Robot Operating System) toolbox under Matlab. The outcomes will be presented at the end of this paper

ORGANIZING BIORHYTHM CYCLES AND THEIR IMPORTANCE TO ATHLETES IN THE CONTEXT OF THE REQUIREMENTS OF MODERN SPORTS TRAINING

The ever-increasing athletic performances in speed, strength and skills used in sports performance around the world has made the athlete more stressful to achieve their own objectives. This stress and pressure on the athlete's body will certainly result in injuries. The research is meant to identify the Biorhythm, its different Cycles and how to organize and perceive their impact on athletes.  Article visualizations

THE CONSUMPTION CULTURE OF SPORTS AND ENERGY DRINKS AND THEIR EFFECTS ON THE ATHLETE’S HEALTH

The consumption of energy drinks has grown considerably in recent years by virtue of which it occupies the beverage market today, and promoted its ability to promote energy levels and vigilance. It contains caffeine as an essential ingredient and other substances such as chlorine, enositol and glucuronolactone. The aim of this study is to understand the views of athletes and their awareness of the impact of energy drinks on tools. Materials: The questionnaire was used to include two axes, the first of which is the knowledge of athletes' awareness of the difference between sports drinks and energy drinks. The second is the health problems caused by energy drinks for athletes. Research methods: The descriptive approach and the study sample included 32 athletes who were deliberately selected. Results: The results were as follows: Most athletes do not realize the difference between drinkers and do not know the risks of energy drinks to their health and the risks they may pose. Conclusion: The results of the studies today are to sensitize and educate the athletes about what may cause these drinks problems on their health, and the athlete to take all the necessary precautions and know the perfect drink that covers the needs without compromising his health.  Article visualizations

THE IMPACT OF PROPOSED EXERCISES IN THE METHOD OF PLYOMETRIC TRAINING IN THE DEVELOPMENT OF EXPLOSIVE POWER AND SOME BASIC SKILLS OF HANDBALL CATEGORY (U17)

This study aimed to investigate the impact of plyometric training method on developing the explosive power and some basic skills in handball, by performing an experimental study where researchers chose one group pattern. This study was fulfilled on a sample of 12 players of Wafaa club in Ainwasara that belongs to Handball association of wilaya of Blida. After applying the suggested exercises, both pre-test results and post-test results of the explosive power (for upper and lower limbs) and some basic skills (performing the skills of aiming from jumping, passing and receiving the ball, dribble) were collected. The researchers treated these results statistically using arithmetic average, standard deviation, Pearson correlation coefficient, T test, therefore, they came to the fact that there are significant statistical significance for dimensional tests in the physical tests (the explosive power of the arms, the explosive power of the legs), and there are also differences of statistical significance for dimensional test in skills tests (aiming from jumping, passing and receiving the ball, dribble). Basing on that, the researchers recommend the necessity of encouraging the coaches on using the plyometric training method due to its big importance in developing the physical and skills sides and avoiding the traditional followed methods. In addition, they also emphasize the necessity of linking between some kinetic and physical abilities and also the performance of the different skills in handball as well as adopting some plyometric training exercises in order to develop the explosives power which is very imperative for many skills.  Article visualizations

DETERMINATION OF THE AGILITY CONTRIBUTION IN THE ACCURACY OF THE OVERWHELMING RATIONAL SHOOTING OF THE VOLLEYBALL YOUNGSTERS

The study aimed to determine the Agility contribution ratio in the accuracy of the Overwhelming shooting of the volleyball youngsters, where the researchers used the descriptive approach in its two methods associative and analytical approach center regional Algiers. The research sample has included 24 players from the second national department Center regional Algiers randomly chosen from the original group of (120) players percentage of 20%. The researcher used the Agility Test and the Overwhelming rational shooting Skill Test. The SPSS statistical package program was also used to analyze the results of the study and in the end, the following has been reached:there is a statistically significant correlation between the Agility and the Overwhelming rational shooting of the volleyball youngstersthe proportion of the contribution of Agility in Overwhelming rational shooting was good, which confirms the effectiveness of this capacity in the performance of the skill.draw an equation from which we can accurately predict the results in Overwhelming rational shooting in indication of the volleyball youngsters Agility.Accordingly, the researcher recommended the need to pay more attention to overwhelming rational shooting for players during the training sessions, rely on the predictive equivalent resulting from this study, and make studies on the contribution of other physical and kinetic abilities in various offensive and defensive skills in volleyball.  Article visualizations