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Effect of Nitrogen Ion Implantation on the Surface Hardness, Corrosion Rate, and Crystal Structure of Pure Aluminium
Dwi Priyantoro,
Emy Mulyani,
Tjipto Sujitno
Issue:
Volume 8, Issue 4, December 2019
Pages:
137-141
Received:
22 July 2019
Accepted:
16 September 2019
Published:
9 October 2019
Abstract: The weakness of aluminium and its alloys are relative low hardness and wear resistance. To improve this weakness a nitrogen ion implantation technique has been carried out. For the purpose, an ion implantation process was carried out for various of dose such as 0.578×1016 ion/cm2, 0.706×1016 ion/cm2, 0.842×1016 ion/cm2, 0.970×1016 ion/cm2, and 1.106×1016 ion/cm2 at a certain energy and beam current, 60 keV and 75 μA, respectively. Hardness test was performed using microhardness tester, the corrosion resistance was tested using the electrochemical method, and the crystal structure was analyzed using X-ray diffraction. From the hardness test result, it can be concluded that the optimum hardness in order of 37.5 VHN was achieved at an ion dose of 0.83×1017 ion/cm2. While the hardness for the untreated sample was 18.70 VHN. It meant, there is an increasing hardness by a factor of 100,53%. At these conditions, the corrosion rate reduces from 0.012 mmpy to 0.011 mmpy or reduce by a factor of 8.3%. Based on the XRD analysis, it can be obtained the AlN phase is formed through the peaks at 2-theta was 39.37° (111), 45.76° (200), and 66.88° (202).
Abstract: The weakness of aluminium and its alloys are relative low hardness and wear resistance. To improve this weakness a nitrogen ion implantation technique has been carried out. For the purpose, an ion implantation process was carried out for various of dose such as 0.578×1016 ion/cm2, 0.706×1016 ion/cm2, 0.842×1016 ion/cm2, 0.970×1016 ion/cm2, and 1.10...
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Environmentally Benign All-inorganic Perovskite Solar Cells
Liqiu Zheng,
Robert S. Owor,
Zhongrui Li
Issue:
Volume 8, Issue 4, December 2019
Pages:
142-155
Received:
19 September 2019
Accepted:
29 September 2019
Published:
14 October 2019
Abstract: Organic/inorganic hybrid lead halide perovskite solar cells have recently emerged as the forerunner in the next generation of photovoltaic technology due to unprecedented progress in power conversion efficiency from their debut of 3.8% in 2009 to the currently certified 23.3%. Mixed PSC solar cells are subject to compositional degradation when exposed to ambient surroundings, which thwarts their real-world applications. Moreover, lead-based compounds pose environmental/health hazards. Very recently, all-inorganic lead-free perovskites have attracted enormous attention because this type successfully dismantles two roadblocks—instability and toxicity, which would accelerate the commercialization. In this outlook, we offered our perspective on the most recent developments in material sciences of halides all inorganic perovskites with possible alternatives to lead, the synthesis approaches, assessment of various device configurations and their progress in solar cells. For the sake of comparison, we also reviewed some all-inorganic but lead-based counterparts in order to motivate researchers to explore all the potentials. Surveying recent developments toward lead-free all-inorganic perovskite solar cells would offer a roadmap for developing new materials and navigate uncharted territory in solar energy fields.
Abstract: Organic/inorganic hybrid lead halide perovskite solar cells have recently emerged as the forerunner in the next generation of photovoltaic technology due to unprecedented progress in power conversion efficiency from their debut of 3.8% in 2009 to the currently certified 23.3%. Mixed PSC solar cells are subject to compositional degradation when expo...
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Results of Theoretical and Experimental Researches of Anomalous Low Friction and Wear in Tribosystems
Viacheslav Stadnychenko,
Valeriy Varvarov
Issue:
Volume 8, Issue 4, December 2019
Pages:
156-165
Received:
30 August 2019
Accepted:
7 October 2019
Published:
25 October 2019
Abstract: The paper presents results of theoretical and experimental researches of anomalously low friction from the standpoint of thermodynamics of non-equilibrium processes occurring under conditions of elastic interaction of microrelief of tribosystem elements. The search of theoretical prerequisites for the transfer of external friction from the "normal mode" to “abnormally low friction mode” is a timely and urgent task which this article addressed to. The conditions for achieving of the abnormally low friction and wear are the creation of the most favorable conditions for microcontact quasi-elastic interaction arising at the microrelief level. The rheological and structural conditions for the transformation of the external input energy by the contact interaction of the roughness of the surface layer of tribosystems are presented. Research have shown that the rheological properties of the surface layer are the main reason for the transition of tribosystems to abnormally low friction and wear mode. The analysis of the contact interaction of the roughnesses by the model of solid body in the form of interatomic bonds made possible to estimate the elastic energy which is released during the destruction of the bonds due to the coupling of the microroughnesses. The evaluation of the interaction as a Markov process with two bilateral states (decay and recovery) made possible to obtain a mathematical dependence of the generalized component of the impulse of force on the contact spot in the coupling state and the parameter of the distribution of contact spots by the modulus of canonical distribution of contact energy on the contact line.
Abstract: The paper presents results of theoretical and experimental researches of anomalously low friction from the standpoint of thermodynamics of non-equilibrium processes occurring under conditions of elastic interaction of microrelief of tribosystem elements. The search of theoretical prerequisites for the transfer of external friction from the "normal ...
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A Hybrid Q-switched Yb3+s-doped All-fiber Laser Based on the Acousto-optic Q-switch and SBS Effect
Lianju Shang,
Hui Xu,
Zhenzhong Cao,
Mingsheng Niu
Issue:
Volume 8, Issue 4, December 2019
Pages:
166-169
Received:
30 September 2019
Accepted:
18 October 2019
Published:
25 October 2019
Abstract: In the past 30 years, the studies on Q-switched fiber lasers have made great progress in both theoretical and experimental fields. So far there have been many reports about the acousto-optic active Q-switched fiber lasers. At the same time, there are many reports about the passive Q-switched pulse output using SBS effect in optical fibers, and this Q-switched mechanism based on SBS effect has become a simple and feasible scheme to narrow the pulse width. However, there are few reports about the Q-switched all-fiber lasers which have the two advantages mentioned above simultaneously. Theoretically the active and passive hybrid Q-switch can make the laser pulse stable and narrow. In this paper, by using the acousto-optic Q-switch and the SBS effect, the operation of a hybrid Q-switched Yb3+-doped all-fiber laser is realized. The pulse width 150ns is obtained at the repetition rate 50kHz. Furthermore, the output wavelength is 1083nm, with the pulse energy 0.02mJ and the peak power 133W achieved. In this experiment, the acousto-optic Q-switch and single-mode fiber play the role of Q-switching at the same time. The active acousto-optic Q-switch plays the role of frequency stabilization. The SBS effect in single-mode fiber plays the role of compressing pulse width. Hence the advantages of active and passive Q-switching modes are reflected.
Abstract: In the past 30 years, the studies on Q-switched fiber lasers have made great progress in both theoretical and experimental fields. So far there have been many reports about the acousto-optic active Q-switched fiber lasers. At the same time, there are many reports about the passive Q-switched pulse output using SBS effect in optical fibers, and this...
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Analysis of Active Mechanism of Chemical Activated Strontium Slag
Hongzhou Zhu,
Li Ou,
Daqian Wang,
Lanxin Hu,
Erhu Yan
Issue:
Volume 8, Issue 4, December 2019
Pages:
170-175
Received:
16 October 2019
Accepted:
6 November 2019
Published:
21 November 2019
Abstract: In order to improve the activity of strontium slag, the mixed cementitious material of strontium slag cement was prepared by adding 30% (mass fraction) of pulverized strontium slag into cement. Chemical activators such as Na2SiO4, NaOH, CaCl2, NaCl, Ca(OH)2, Na2SO4 were added to the cementitious material. The flexural and compressive strength values of 3d, 7d, 28d were obtained by mortar strength test, and were used as the base with standard samples. The mechanism of activator improving the activity of strontium slag is analyzed. CaCl2 and NaCl are cement early strength agents. So the substitution of strontium slag with silica powder is compared. The strength of strontium slag is judged by principle analysis. The results show that NaOH and Ca(OH)2 are beneficial to the activation of SiO2 and Al2O3, but the amount of ettringite is large and the strength is reduced, so there is a certain active excitation for strontium slag, but the effect is not very good; the addition of Na2SiO4 causes damage to volume stability and it is the worst of all activators. the compressive strength increases rapidly in 3d and 7d after adding NaCl, so it is mainly to stimulate the early strength of cement; The 28d compressive strength of strontium slag cement containing CaCl2 is higher than that of strontium slag cement containing other chemical activators, which can reach 91% of the compressive strength of cement mortar. It is preliminarily judged that CaCl2 has an exciting effect on strontium slag and the exciting effect is obvious.
Abstract: In order to improve the activity of strontium slag, the mixed cementitious material of strontium slag cement was prepared by adding 30% (mass fraction) of pulverized strontium slag into cement. Chemical activators such as Na2SiO4, NaOH, CaCl2, NaCl, Ca(OH)2, Na2SO4 were added to the cementitious material. The flexural and compressive strength value...
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Gas Ingress and Egress of MEMS Multi-Chip Modules and MEMS Devices
Lu Fang,
Lyle Alexander Menk
Issue:
Volume 8, Issue 4, December 2019
Pages:
176-182
Received:
12 November 2019
Accepted:
5 December 2019
Published:
13 December 2019
Abstract: Hermetic microcircuit packaging was the dominant method of protecting semiconductor devices in the 1960s and 1970s. After losing majority market sectors to plastic encapsulated microelectronics over the last a few decades, hermetic packaging remains the preferred method of protecting semiconductor devices for critical applications such as in military, space, and medical fields, where components and systems are required to serve for several decades. MEMS devices impose additional challenges to packaging by requiring specific internal cavity pressures to function properly or deliver the needed quality (Q) factors. In MEMS multichip modules, internal pressure requirement conflicts arise when different MEMS devices require different internal gases and pressures. The authors developed a closed-formed equation to model pressure changes of hermetic enclosures due to gas ingression. This article expands the authors mathematical model to calculate gas pressure of a MEMS multichip module package as well as those of MEMS devices inside the multichip module package. These equations are not only capable of calculating service lifetimes of MEMS devices and multi-chip modules but can also help develop MEMS device packaging strategies to extend the service life of MEMS multi-chip modules.
Abstract: Hermetic microcircuit packaging was the dominant method of protecting semiconductor devices in the 1960s and 1970s. After losing majority market sectors to plastic encapsulated microelectronics over the last a few decades, hermetic packaging remains the preferred method of protecting semiconductor devices for critical applications such as in milita...
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