A Chemism Analysis of Alkali in the Chemical Mechnical Polishing Process of SiC Substrate

2014 ◽  
Vol 1027 ◽  
pp. 208-212
Author(s):  
Jian Guo Yao ◽  
Li Jie Ma ◽  
Su Fang Fu ◽  
Zhan Kui Wang ◽  
Jian Xiu Su
Keyword(s):  
Removal Rate ◽  
Chemical Characteristic ◽  
Material Surface ◽  
Polishing Process ◽  
Organic Bases ◽  
Crystal Substrate ◽  
Ph Modifier ◽  
The Stability

In this study, according to physic-chemical characteristic of the SiC crystals, we analyzed and researched the role of pH modifier in SiC crystal substrate chemical mechanical polishing and the surface after polishing. We used different polish agents which was made up with inorganic and organic bases to experiment, and then analyzed the results. The parameters of the polishing specimen, such as the removal rate of material, surface scanning and the roughness, were analyzed and used to determine the different pH modifiers played different roles in the stability of polish agents and surface quality of the specimen.

Achieving Highly Stable Removal Rate in Small Tool Polishing of Glass Lenses

2020 ◽  
Author(s):  
Urara Satake ◽  
Toshiyuki Enomoto ◽  
Teppei Miyagawa ◽  
Takuya Ohsumi
Keyword(s):  
Removal Rate ◽  
Industrial Applications ◽  
Polishing Process ◽  
The Stability ◽  
Sudden Decrease ◽  
Polishing Pads ◽  
Glass Lenses ◽  
Polishing Pressure ◽  
Small Tool

Abstract The demand for improving the image quality of cameras has increased significantly, especially in industrial applications, such as broadcasting, on-vehicle, security, factory automation, and medicine. Surface of glass lenses, which is a key component of cameras, is formed and finished by polishing using small tools. However, the existing small tool polishing technologies exhibit serious problems including an unstable removal rate with the accumulated polishing time. In concrete, low removal rate at the beginning of the polishing process and sudden decrease in the removal rate during the polishing process significantly deteriorate stability of the removal rate. To improve the stability of the removal rate, we proposed a vibration-assisted polishing method using newly developed polishing pads with titanium dioxide particles in the previous work. Polishing experiments on glass lenses confirmed that the variation in the removal rate was suppressed by the developed polishing method; however, the reason for the improvement, in concrete, the relation between the vibration of polishing pressure and the stability of the removal rate remains unknown. In this study, we investigated and clarified the effect of the vibration of polishing pressure on the surface conditions of polishing pads, which strongly affected removal rate.

Analysis of Chemical Action of Oxidants in Chemical Mechanical Polishing of SiC Crystal Substrate

2014 ◽  
Vol 1027 ◽  
pp. 213-216
Author(s):  
Su Fang Fu ◽  
Jian Guo Yao ◽  
Li Jie Ma ◽  
Jian Xiu Su
Keyword(s):  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Removal Rate ◽  
Mechanical Polishing ◽  
Key Factors ◽  
Chemical Action ◽  
Crystal Substrate ◽  
The Stability ◽  
Polishing Efficiency

Chemical mechanical polishing (CMP) had been considered as the most practical and effective method of achieving an ultra-smooth and non-damage surface in manufacturing SiC crystal substrate. CMP slurry was one of the key factors of CMP technology. In this paper, through investigating the changes of several core factors to evaluate the performance of CMP, such as the material removal rate (MRR), surface roughness Ra, 3D surface profiler, etc., the influence of various slurry and its content on the polishing efficiency and surface finish quality had been studied. The research results showed that different oxidant had different chemical action mechanism, also affecting the stability of CMP slurry and surface quality of specimen; adding suitable an oxidant to slurry could effectively improve the CMP performance.

Structural and functional analysis of reconnaissance and fire system and decomposition of its functions and subsystems

2021 ◽  
pp. 38-48
Author(s):  
O. Maistrenko ◽  
O. Karavanov ◽  
A. Shcherba
Keyword(s):  
Functional Analysis ◽  
Fire Damage ◽  
Expert Group ◽  
Expert Evaluation ◽  
Military Conflicts ◽  
Main Factors ◽  
The Stability ◽  
The Impact

It is established that the role of reconnaissance and fire systems in the implementation of enemy fire damage in military conflicts occurring at the beginning of the XXI century. Increased  to 75%. However, it was found that the effectiveness of these systems depends on the quality of their equipment. The main factors that are often not taken into account in the acquisition are the possibility, interoperability, stability of each element, the impact of elements on the stability of each other and the functioning of the RVS as a whole. The analysis of recent research and publications has shown that as of today, the approaches to determining the composition of reconnaissance fire systems taking into account these factors are not justified. Given the above, it was decided to conduct a structural and functional analysis of the reconnaissance fire system and the decomposition of its functions and subsystems. To this end, based on the method of cluster analysis, an algorithm for combining a set of tasks performed by reconnaissance and fire systems into groups has been developed and substantiated. The method of expert evaluation was used to obtain substantiated data on the implementation of such a merger. According to the proposed algorithm, the main tasks were first identified, which involve reconnaissance and fire systems. Subsequently, an expert group was formed and the coefficient of relative competence of each member of the expert group was determined. The experts were then asked to combine the identified tasks according to their characteristics into an arbitrary number of groups. After processing the opinions of experts, 10 characteristic groups were identified. Finally, the experts were asked to combine the obtained groups in such a way that each association consisted of similar objects and the objects of different associations differed significantly. The results of the work revealed the functional interconnectedness of the tasks, processes and subsystems of the reconnaissance and fire system. It is also established that a typical reconnaissance fire system will consist of three subsystems (control, reconnaissance and fire influence), which perform specific functions for each of them.

Stabilization of Removal Rate in Small Tool Polishing of Glass Lenses

2019 ◽  
Vol 13 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Urara Satake ◽  
Toshiyuki Enomoto ◽  
Teppei Miyagawa ◽  
Takuya Ohsumi ◽  
Hidenori Nakagawa ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Material Removal Rate ◽  
Time Variation ◽  
Material Removal ◽  
Removal Rate ◽  
Polishing Process ◽  
Polishing Pad ◽  
The Stability ◽  
Polishing Pads ◽  
Glass Lenses

The demand for improving the image quality of cameras has increased significantly, especially in industrial fields such as broadcasting, on-vehicle, security, factory automation, and medicine. The surface of glass lenses as a key component of cameras is formed and finished by polishing using small tools. The existing polishing technologies, however, exhibit serious problems including an unstable material removal rate over time. In our previous work, the mechanism of time variation in material removal rate was clarified. Based on the findings, a vibration-assisted polishing method using polishing pads containing titanium dioxide particles was developed for improving the stability of the material removal rate with the accumulated polishing time. Our experiments revealed that the proposed polishing method suppressed the time variation significantly in the material removal rate. The developed polishing pads, however, possessed a short life because of their poor wear resistance; as such, they could not be applied to the mass-production process of lenses. In this study, we applied the vibration-assisted polishing method to the polishing process using commercial polishing pads that exhibit sufficient wear resistance for practical use. To investigate the effect of vibration on the stability of the material removal rate, polishing experiments and the observation of slurry flow on the surface of the polishing pads during the vibration-assisted polishing process were conducted. Based on the findings, a new polishing method utilizing a large-amplitude high-frequency vibration applied to the polishing pressure was developed. In addition, a new polishing method utilizing the overhang of a polishing pad, where the polishing pad was moved to hang over the edge of the workpiece for incorporating periodic dressing processes of the polishing pad surface during the polishing process, was also developed. Our polishing experiments revealed that both the proposed polishing methods improved the stability of the material removal rate significantly over the course of the polishing process.

An Approach to the Influence of Flotative Abrasive Balls on Polishing Process

2006 ◽  
Vol 532-533 ◽  
pp. 393-396 ◽  
Author(s):  
Yong Dai ◽  
Qian Fa Deng ◽  
Xun Lv ◽  
Ju Long Yuan ◽  
Xun Jie Yu
Keyword(s):  
Surface Roughness ◽  
Grain Size ◽  
Removal Rate ◽  
Great Influence ◽  
Work Piece ◽  
Polishing Process ◽  
Soft Contact ◽  
Ball Diameter ◽  
Experiment Device

Polishing with Flotative Abrasive Balls(FABs) is a kind of soft contact polishing means， and the conventional polishing plate and pad are not needed in this case. The pressure of polishing is the flotage which is the upward force that a fluid exerts on the FABs, but the movement of work piece is similar to that in conventional polishing, the removal rate and quality of polishing is influenced by FAB and its flotage. An experiment device is built up and two kinds of FAB are designed and produced. Some primary experiments are carried out in order to investigate the influences of the size of FABs on the removal rate and surface roughness in polishing with FABs. It is found from the experiments that the grain size and the layers of FAB may have great influence on the removal rate of polishing; the surface roughness is mainly decided by the ball diameter and the layers of FAB. The results of experiments are discussed and analyzed, it indicates that the efficiency and quality depend on flotage and the number of active grains when the velocity of workpiece is assigned.

scholarly journals The Role of Cultivation Systems in Quality Sugar Beet Production

2005 ◽  
pp. 134-138
Author(s):  
Kinga Diána Ungai ◽  
Zoltán Győri
Keyword(s):  
Sugar Beet ◽  
Production System ◽  
Plant Protection ◽  
Plant Production ◽  
High Yield ◽  
Yield And Quality ◽  
The Stability ◽  
Saccharose Content

Producing sugar beet, as it is a demanding field crop, has contributed to the raising standard of plant production. It has an outstanding place among the plants that are cultivated in the intensive plant production system. Rentability of sugar manufacture is determined by the stability of yield and the quality (saccharose content) of sugar beet. In this way, the fundamental interest both of the producers and the processing industry is high yield and quality, year by year. The yield and the quality of the sugar beet are mainly determined by the plant production system, so we studied the effect of fertilization, irrigation and plant protection.

scholarly journals Investigation of the influence of modification of the working tool for the manufacture of niobium case products

2021 ◽  
Vol 2094 (4) ◽  
pp. 042006
Author(s):  
E Yu Remshev ◽  
Z N Rasulov ◽  
S A Voinash ◽  
V A Sokolova ◽  
I A Teterina ◽  
...  
Keyword(s):  
Significant Proportion ◽  
Machine Building ◽  
Test Cycle ◽  
New Methods ◽  
Urgent Task ◽  
Main Production ◽  
The Stability ◽  
Cold Stamping

Abstract The main production of machine-building enterprises of various industries is the production of metal parts and products, 90-95% of which are manufactured using metal processing by pressure. Ensuring the stability of the technological processes of cold stamping is impossible without the use of interoperative coatings, which play the role of lubrication, preventing the diffusion “setting” (interpenetration at the atomic-molecular level) of the processed materials and tools. Therefore, one of the tasks in constructing the technology for manufacturing parts from these materials is to conduct a test cycle to establish the most acceptable coatings at the intermediate stages of processing. In the process of studying the operability and manufacturability, it is also advisable to use new methods for evaluating quality indicators at separate stages of processing semi-finished products and at the stages of control of finished products, which allows practically eliminating defects due to internal defects, ensuring the uniformity of the microstructure and predicting the operability of finished products during operation. Ensuring the quality of stamped semi-finished products made of refractory metals (niobium, molybdenum) is an urgent task due to the significant proportion of defects during cold stamping of these parts.

scholarly journals A viewpoint on material and design considerations for oesophageal stents with extended lifetime

2022 ◽  
Author(s):  
Caitlin E. Jackson ◽  
Liam S. J. Johnson ◽  
Dominic A. Williams ◽  
Hans-Ulrich Laasch ◽  
Derek W. Edwards ◽  
...  
Keyword(s):  
Patient Survival ◽  
Drug Eluting Stent ◽  
Material Surface ◽  
Device Performance ◽  
Stent Design ◽  
Novel Treatments ◽  
Construction Methods ◽  
Drug Eluting

AbstractOesophageal stents are meshed tubular implants designed to maintain patency of the oesophageal lumen and attenuate the symptoms of oesophageal cancer. Oesophageal cancers account for one in twenty cancer diagnoses and can lead to dysphasia, malnutrition and the diminishment of patient quality of life (QOL). Self-expanding oesophageal stents are the most common approach to attenuate these symptoms. Recent advances in oncological therapy have enabled patient survival beyond the lifetime of current devices. This introduces new complications for palliation, driving the need for innovation in stent design. This review identifies the factors responsible for stent failure. It explores the challenges of enhancing the longevity of stent therapies and outlines solutions to improving clinical outcomes. Discussions focus on the role of stent materials, construction methods, and coatings upon device performance. We found three key stent enhancement strategies currently used; material surface treatments, anti-migratory modifications, and biodegradable skeletons. Furthermore, radioactive and drug eluting stent designs were identified as emerging novel treatments. In conclusion, the review offers an overview of remaining key challenges in oesophageal stent design and potential solutions. It is clear that further research is needed to improve the clinical outcome of stents and patient QOL.

Party Systems: Types, Dimensions, and Explanations

2020 ◽  
Author(s):  
Zsolt Enyedi ◽  
Fernando Casal Bértoa
Keyword(s):  
Party System ◽  
Balance Of Power ◽  
Party Systems ◽  
Party Competition ◽  
System Stability ◽  
Informal Institution ◽  
Democratic Experience ◽  
The Stability

The study of political parties and party systems is intimately linked to the development of modern political science. The configuration of party competition varies across time and across polities. In order to capture this variance, one needs to go beyond the analysis of individual parties and to focus on their numbers (i.e. fragmentation), their interactions (i.e. closure), the prevailing ideological patterns (i.e. polarization), and the stability of the balance of power (i.e. volatility) in all spheres of competition, including the electoral, parliamentary, and governmental arenas. Together, these factors constitute the core informal institution of modern politics: a party system. The relevant scholarship relates the stability of party systems to the degree of the institutionalization of individual parties, to various institutional factors such as electoral systems, to sociologically anchored structures such as cleavages, to economic characteristics of the polity (primarily growth), to historical legacies (for example, the type of dictatorship that preceded competitive politics) and to the length of democratic experience and to the characteristics of the time when democracy was established. The predictability of party relations has been found to influence both the stability of governments and the quality of democracy. However, still a lot is to be learned about party systems in Africa or Asia, the pre-WWII era or in regional and/or local contexts. Similarly, more research is needed regarding the role of colonialism or how party system stability affects policy-making. As far as temporal change is concerned, we are witnessing a trend towards the destabilization of party systems, but the different indicators show different dynamics. It is therefore crucial to acknowledge that party systems are complex, multifaceted phenomena.

Study on 6H-SiC Crystal Substrate (0001) C Surface in FA-CMP Based on Diamond Particle

2015 ◽  
Vol 727-728 ◽  
pp. 244-247
Author(s):  
Zhu Qing Zhang ◽  
Kang Lin Xing
Keyword(s):  
Material Removal Rate ◽  
Chemical Mechanical Polishing ◽  
Material Removal ◽  
Removal Rate ◽  
Diamond Particle ◽  
Mechanical Polishing ◽  
Crystal Substrate ◽  
Fixed Abrasive ◽  
Free Abrasive

Through experimental study on the role of the free abrasive in chemical mechanical polishing, in this paper, four different types of abrasive which were chosen were used for the research of material removal rate(MRR) and surface quality of SiC single crystal . Finally ,Diamond abrasive which is considered was the most suitable for chemical mechanical polishing(CMP) abrasive of SiC Crystal Substrate. With diamond Particle polish pad polishing, it is draw a comparison result on the influence of the free abrasive and consolidation abrasive for the material removal rate and surface quality of 6H-SiC. The results showed that: the MRR is 140nm / min, the material removal rate if fixed abrasive chemical mechanical polishing(FA-CMP) more than three times that of traditional CMP, fixed abrasive chemical mechanical polishing pad, are involved in a large proportion of micro abrasive cutting, can greatly improve the material removal efficiency. And results from the test procedure, the FA-CMP surface has scratches after more technical problems for the polishing pad, the surface damage is relatively free of abrasive chemical mechanical polishing is more serious.

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