scholarly journals Role of the Features of Focused Laser Beam at Pulsed Laser Cutting

2019 ◽  
Vol 2 (2) ◽  
pp. 115-120
Author(s):  
György Meszlényi ◽  
Enikő Bitay

Abstract In this article investigation of the roles of two important factors of focused laser beam, the focal spot diameter and the Rayleigh length as determining variables of the beam quality were made. The equations of these two factors are based on those most commonly used in the literature. The exchange between three different beam quality numbers were shown. It is proven on the basis of the scientific literature, that the beam quality degrades compared to the original data given by the factory of laser. The causes of the beam quality degradation are lens aberrations in the optical path of the given laser, and the shifting of the beam propagation ratio (M2) to higher values. A new equation for estimation of the new, lowest value for M2 factor is presented, based on the comparison of the laser cut material thickness to the depth of focus, which is two times the Rayleigh length.

2021 ◽  
Vol 9 ◽  
Author(s):  
Deen Wang ◽  
Xin Zhang ◽  
Wanjun Dai ◽  
Ying Yang ◽  
Xuewei Deng ◽  
...  

Abstract A 1178 J near diffraction limited 527 nm laser is realized in a complete closed-loop adaptive optics (AO) controlled off-axis multi-pass amplification laser system. Generated from a fiber laser and amplified by the pre-amplifier and the main amplifier, a 1053 nm laser beam with the energy of 1900 J is obtained and converted into a 527 nm laser beam by a KDP crystal with 62% conversion efficiency, 1178 J and beam quality of 7.93 times the diffraction limit (DL). By using a complete closed-loop AO configuration, the static and dynamic wavefront distortions of the laser system are measured and compensated. After correction, the diameter of the circle enclosing 80% energy is improved remarkably from 7.93DL to 1.29DL. The focal spot is highly concentrated and the 1178 J, 527 nm near diffraction limited laser is achieved.


2021 ◽  
Vol 2021 (5) ◽  
pp. 18-23
Author(s):  
S.V. Adjamskyi ◽  
◽  
G.A. Kononenko ◽  
R.V. Podolskyi ◽  
◽  
...  

2001 ◽  
Vol 8 (6) ◽  
pp. 416-421
Author(s):  
Yusuke Ogura ◽  
Jun Tanida ◽  
Yoshiki Ichioka ◽  
Yoshiaki Mokuno ◽  
Katsunori Matsuoka

Procedia CIRP ◽  
2018 ◽  
Vol 74 ◽  
pp. 466-469 ◽  
Author(s):  
Kerstin Schaumberger ◽  
Vincent Mann ◽  
Michael Mödl ◽  
Konstantin Hofmann ◽  
Stefan Stein ◽  
...  

2021 ◽  
Vol 2021 (5) ◽  
pp. 21-27
Author(s):  
S.V. Adjamskiy ◽  
◽  
G.A. Kononenko ◽  
R.V. Podolskyi ◽  
◽  
...  

Author(s):  
D. A. Carpenter ◽  
Ning Gao ◽  
G. J. Havrilla

A monolithic, polycapillary, x-ray optic was adapted to a laboratory-based x-ray microprobe to evaluate the potential of the optic for x-ray micro fluorescence analysis. The polycapillary was capable of collecting x-rays over a 6 degree angle from a point source and focusing them to a spot approximately 40 µm diameter. The high intensities expected from this capillary should be useful for determining and mapping minor to trace elements in materials. Fig. 1 shows a sketch of the capillary with important dimensions.The microprobe had previously been used with straight and with tapered monocapillaries. Alignment of the monocapillaries with the focal spot was accomplished by electromagnetically scanning the focal spot over the beveled anode. With the polycapillary it was also necessary to manually adjust the distance between the focal spot and the polycapillary.The focal distance and focal spot diameter of the polycapillary were determined from a series of edge scans.


2020 ◽  
pp. 15-27

In order to study the effect of phosphogypsum and humic acids in the kinetic release of salt from salt-affected soil, a laboratory experiment was conducted in which columns made from solid polyethylene were 60.0 cm high and 7.1 cm in diameter. The columns were filled with soil so that the depth of the soil was 30 cm inside the column, the experiment included two factors, the first factor was phosphogypsum and was added at levels 0, 5, 10 and 15 tons ha-1 and the second-factor humic acids were added at levels 0, 50, 100 and 150 kg ha-1 by mixing them with the first 5 cm of column soil and one repeater per treatment. The continuous leaching method was used by using an electrolytic well water 2.72 dS m-1. Collect the leachate daily and continue the leaching process until the arrival of the electrical conductivity of the filtration of leaching up to 3-5 dS m-1. The electrical conductivity and the concentration of positive dissolved ions (Ca, Mg, Na) were estimated in leachate and the sodium adsorption ratio (SAR) was calculated. The results showed that the best equation for describing release kinetics of the salts and sodium adsorption ratio in soil over time is the diffusion equation. Increasing the level of addition of phosphogypsum and humic acids increased the constant release velocity (K) of salts and the sodium adsorption ratio. The interaction between phosphogypsum and humic acids was also affected by the constant release velocity of salts and the sodium adsorption ratio. The constant release velocity (K) of the salts and the sodium adsorption ratio at any level of addition of phosphogypsum increased with the addition of humic acids. The highest salts release rate was 216.57 in PG3HA3, while the lowest rate was 149.48 in PG0HA0. The highest release rate of sodium adsorption ratio was 206.09 in PG3HA3, while the lowest rate was 117.23 in PG0HA0.


Author(s):  
Ирина Викторовна Евстафьева

В статье исследуются вопросы попечительства в отношении несовершеннолетних, отбывающих наказание в виде лишения свободы. Проблема, поднимаемая автором настоящей статьи, многогранна, касается различных аспектов отбывания наказания несовершеннолетними в воспитательных колониях и требует комплексного исследования, способного ответить на определенно значимый вопрос: является ли колония законным представителем находящихся в ней несовершеннолетних со всеми вытекающими из статуса законных представителей последствиями. При этом необходимо обращать внимание на специфику правового статуса лиц, отбывающих наказание в воспитательных колониях, которые, во-первых, являются несовершеннолетними, то есть не обладают дееспособностью в полном объеме и нуждаются в особой заботе, защите и представительстве, а во-вторых, осуждены за совершение тяжкого или особо тяжкого преступления, влекущего изоляцию от общества и определенные ограничения и лишения. Отечественное законодательство достаточно детально регламентирует особенности режима отбывания наказания в виде лишения свободы несовершеннолетними, не определяя при этом статуса воспитательных колоний, кем они являются: воспитателями, попечителями или исключительно учреждениями исполнения наказаний. Между тем правильное понимание значения и роли воспитательной колонии в жизни находящихся в ней несовершеннолетних преступников, по мнению автора, поможет избежать ряда проблем, объективно складывающихся в учреждениях подобного рода. С этой точки зрения предлагаемая тема представляет интерес не только для ученых-теоретиков, но и для практиков - сотрудников соответствующих учреждений. Особо следует подчеркнуть, что исследований по данной тематике в специальной литературе нет. Отдельные исследования, встречающиеся в современной литературе, касаются исключительно общего гражданско-правового статуса несовершеннолетних осужденных. Однако это обстоятельство может свидетельствовать только о новизне данной темы, но никак не об отсутствии самой проблемы. The article analyzes the issues of the status of educational colonies as guardians of minors serving a sentence of imprisonment. In fact, the problem raised by the author of this article is multifaceted, concerns various aspects of the serving of punishment by minors in educational colonies and requires a comprehensive study that can answer, it seems, a definitely significant question: whether the colony is the legal representative of the minors in it with all the consequences arising from the status of legal representatives in the form of duties and responsibilities. At the same time, it seems, it is necessary to pay attention to the specifics of the legal status of citizens serving sentences in educational colonies, who, firstly, are minors, i.e. do not have full legal capacity and need special care, protection and representation, and, secondly, are convicted of committing a serious or particularly serious crime, entailing isolation from society and certain restrictions and deprivation. Domestic legislation regulates in sufficient detail the peculiarities of the regime of serving sentences in the form of deprivation of liberty by minors, without determining the status of educational colonies. Who are they: educators, Trustees or only institutions of execution of punishments. Meanwhile, the correct understanding of the importance and role of the educational colony in the life of juvenile offenders in it, according to the author, will help to avoid a number of problems that objectively develop in institutions of this kind. From this point of view, the proposed topic is of interest not only for theoretical scientists, but for practitioners-employees of relevant institutions. It should be emphasized that there are no studies on this subject in the special literature. However, this circumstance can testify only about novelty of the given subject, but in any way about absence of the problem. It seems that the relevance and importance of a problem is not always measured by the number of studies devoted to it. Sometimes these its traits are manifest only under particularly careful consideration.


2021 ◽  
Vol 22 (15) ◽  
pp. 7975
Author(s):  
Saioa Gómez-Zorita ◽  
Iñaki Milton-Laskibar ◽  
Laura García-Arellano ◽  
Marcela González ◽  
María P. Portillo

The present review is aimed at analysing the current evidence concerning the potential modulation of obesity and/or diet in adipose tissue ACE2. Additionally, the potential implications of these effects on COVID-19 are also addressed. The results published show that diet and obesity are two factors that effectively influence the expression of Ace2 gene in adipose tissue. However, the shifts in this gene do not always occur in the same direction, nor with the same intensity. Additionally, there is no consensus regarding the implications of increased adipose tissue ACE2 expression in health. Thus, while in some studies a protective role is attributed to ACE2 overexpression, other studies suggest otherwise. Similarly, there is much debate regarding the role played by ACE2 in COVID-19 in terms of degree of infection and disease outcomes. The greater risk of infection that may hypothetically derive from enhanced ACE2 expression is not clear since the functionality of the enzyme seems to be as important as the abundance. Thus, the greater abundance of ACE2 in adipose tissue of obese subjects may be counterbalanced by its lower activation. In addition, a protective role of ACE2 overexpression has also been suggested, associated with the increase in anti-inflammatory factors that it may produce.


2021 ◽  
pp. 245513332110316
Author(s):  
Tiken Das ◽  
Pradyut Guha ◽  
Diganta Das

This study made an attempt to answer the question: Do the heterogeneous determinants of repayment affect the borrowers of diverse credit sources differently? The study is based on data collected from 240 households from three districts in the lower Brahmaputra valley of Assam through a carefully designed primary survey. Besides, the study uses the double hurdle approach and the instrumental variable probit model to reduce possible selection bias. It observes better repayment performance among formal borrowers, followed by semiformal borrowers, while occupation wise it is prominent among organised employees. It has been found that in general, the household characteristics, loan characteristics and location-specific characteristics significantly affect repayment performance of borrowers. However, the nature of impact of the factors influencing repayment performance is remarkably different across credit sources. It ignores the role of traditional community-based organisations in rural Assam while analysing the determinants of repayment performance. The study also recommends for ensuring productive opportunities and efficient market linkages in rural areas of Assam. The study is based on an original data set that has specially been collected to examine question that—do the heterogeneous determinants of repayment affect the borrowers of diverse credit sources differently in the lower Brahmaputra valley of Assam—which has not been studied before.


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