Study on Relationship of the Material Removal Amount and the Increase in Abrasive Nanoparticle Size during Si-CMP

2018 ◽  
Author(s):  
Siriwan Boripatkosol ◽  
Natthaphon Bun-Athuek ◽  
Panart Khajornrungruang ◽  
Keisuke Suzuki ◽  
Narin Chanthawong ◽  
...  
Keyword(s):  
Material Removal ◽  
Nanoparticle Size ◽  
Relationship Of

Study on Technological Parameters of Polishing Large Aspheric Elements

2012 ◽  
Vol 630 ◽  
pp. 142-147
Author(s):  
Xian Hua Chen ◽  
Bo Zhong ◽  
Zhi Gang Yuan
Keyword(s):  
Influencing Factors ◽  
Material Removal ◽  
Principal Axis ◽  
Rotational Velocity ◽  
Technological Parameters ◽  
Function Model ◽  
Laser Facility ◽  
Computer Controlled ◽  
Relationship Of ◽  
Polishing Pressure

Large aspheric elements in giant laser facility are fabricated using computer controlled rapid polishing technology. The technological parameters are main influencing factors of efficiency. Base on Preston hypothesis, linear relationship of material removal with polishing pressure, polishing velocity and other conditions are established. According to the material removal function model of computer controlled rapid polishing, the removal function is simulated using MATLAB software. The influencing factors of volume removal efficiency are analyzed. In practice, the optimum polishing parameters are eccentricity 0.4, rotational velocity of principal axis 330 rpm, rotational velocity of polishing pad -600 rpm.

Study on Cutting Force of Diamond Cutter in Special-Shaped Stone Processing

2011 ◽  
Vol 291-294 ◽  
pp. 804-809 ◽  
Author(s):  
Bo Huang ◽  
Zeng Wen Liu
Keyword(s):  
Cutting Force ◽  
Material Removal Rate ◽  
Feed Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Key Factors ◽  
Peripheral Speed ◽  
Factors Influencing ◽  
Relationship Of ◽  
The Relationship

The cutting force is the key factors influencing the processing precision and efficiency in special-shaped stone production. In this research, the cutting force is measured and analyzed in the process of special shaped cutter cutting stone. It is found that the relationship of cutting force with peripheral speed of cutter is nearly inverse proportional. The cutting force becomes smaller and smaller as the peripheral speed of cutter increases. The relationship of cutting force with feed rate is nearly proportional. The cutting force becomes larger and larger as the feed rate increases. The relationship between Fx, Fy and Fz is Fz > Fx > Fy. Enhancing the peripheral speed of cutter is a better way to increase the material removal rate.

Dynamic Model of Material Removal Process in Through-Feed Centerless Grinding Based on the Lagrange Equation

2015 ◽  
Vol 667 ◽  
pp. 173-180 ◽  
Author(s):  
Cui Qi ◽  
Shi Jin Chen ◽  
Hui Ding ◽  
Kai Cheng
Keyword(s):  
Material Removal ◽  
Lagrange Equation ◽  
Grinding Wheel ◽  
Removal Process ◽  
3D Space ◽  
Centerless Grinding ◽  
Control Wheel ◽  
Geometric Relationship ◽  
And Control ◽  
Relationship Of

Due to the unfixed state of the workpiece and the dissimilarity between sections in through-feed centerless grinding, the positions and orientations of the workpiece keep changing in the grinding process, which are coupled with the workpiece roundness generation. In this paper the positions and orientations of the workpiece are described by the dynamic equations obtained from Lagrange equation. And the homogeneous coordinate transformation is applied to present the profiles of the workpiece, grinding wheel and control wheel in the reference frame. Finally the time varying profile of the workpiece is obtained for the investigation of the material removal process in 3D space. The material properties of the workpiece, the wheels and the workrest combined with the geometric relationship of their profiles are utilized to calculate the interaction between them, including the three forces along the axes and the three moments about the axes.

Smoothing Mechanism of Reaction Sintered SiC in Plasma Assisted Polishing Using Ceria Abrasive

2012 ◽  
Vol 516 ◽  
pp. 119-124
Author(s):  
Hui Deng ◽  
Masaki Ueda ◽  
Kazuya Yamamura
Keyword(s):  
Material Removal Rate ◽  
Oxidation Rate ◽  
Material Removal ◽  
Removal Rate ◽  
Rf Power ◽  
Plasma Irradiation ◽  
Oxidation Rates ◽  
Mechanism Of Reaction ◽  
Lower Load ◽  
Relationship Of

For the finishing of some difficult-to-machine materials, a novel polishing technique named plasma assisted polishing (PAP) was proposed. Ceria abrasive polishing with different electric power plasma irradiation was conducted on RS-SiC surface. Low RF power plasma (8 W) was used, many protrusions were generated which made the surface roughnesses bad (60.93 nm p-v, 5.51 nm rms). In contrast, the height and amount of protrusions decreased when RF power was increased to 12 W, which made the surface roughness better (31.83 nm p-v, 2.63 nm rms). Also, scratches completely disappeared after PAP. To explain the above results, the relationship of oxidation rate by plasma irradiation and material removal rate by abrasive polishing was taken into consideration. The different compositions in RS-SiC have different oxidation rates and levels of hardness. When the oxidation rate is higher than material removal rate, the heterogeneous polishing of RS-SiC is turned to homogeneous polishing of SiO2, and then a flat surface with an oxide layer can be obtained. To prove the above assumption, we firstly oxidized the surface with plasma irradiation for 1 h, and then PAP with a much lower load was conducted on the oxidized surface for 0.5 h. A scratch-free surface with 12.61 nm p-v and 1.45 nm rms was obtained which coincides with the mechanism we propose.

The relationship of the scleractinian corals to the rugose corals

Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver
Keyword(s):  
Critical Points ◽  
Scleractinian Corals ◽  
Convincing Evidence ◽  
Early Triassic ◽  
Rugose Corals ◽  
History Of ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Biologic Factors

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Studies on Leukemogenic and Sarcomagenic Viruses

1970 ◽  
Vol 28 ◽  
pp. 156-157
Author(s):  
Leon Dmochowski
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Morphological Properties ◽  
Mode Of Development ◽  
Relationship Of ◽  
The Relationship

Electron microscopy has proved to be an invaluable discipline in studies on the relationship of viruses to the origin of leukemia, sarcoma, and other types of tumors in animals and man. The successful cell-free transmission of leukemia and sarcoma in mice, rats, hamsters, and cats, interpreted as due to a virus or viruses, was proved to be due to a virus on the basis of electron microscope studies. These studies demonstrated that all the types of neoplasia in animals of the species examined are produced by a virus of certain characteristic morphological properties similar, if not identical, in the mode of development in all types of neoplasia in animals, as shown in Fig. 1.

The relationship of IGE receptor topography to signaling activity in RBL-2H3 mast cells

1991 ◽  
Vol 49 ◽  
pp. 236-237
Author(s):  
J.R. Pfeiffer ◽  
J.C. Seagrave ◽  
C. Wofsy ◽  
J.M. Oliver
Keyword(s):  
Mast Cells ◽  
Protein A ◽  
Scattered Electron ◽  
Ige Receptor ◽  
Receptor Complexes ◽  
Ige Binding ◽  
Electron Imaging ◽  
Small Clusters ◽  
Relationship Of ◽  
The Relationship

In RBL-2H3 rat leukemic mast cells, crosslinking IgE-receptor complexes with anti-IgE antibody leads to degranulation. Receptor crosslinking also stimulates the redistribution of receptors on the cell surface, a process that can be observed by labeling the anti-IgE with 15 nm protein A-gold particles as described in Stump et al. (1989), followed by back-scattered electron imaging (BEI) in the scanning electron microscope. We report that anti-IgE binding stimulates the redistribution of IgE-receptor complexes at 37“C from a dispersed topography (singlets and doublets; S/D) to distributions dominated sequentially by short chains, small clusters and large aggregates of crosslinked receptors. These patterns can be observed (Figure 1), quantified (Figure 2) and analyzed statistically. Cells incubated with 1 μg/ml anti-IgE, a concentration that stimulates maximum net secretion, redistribute receptors as far as chains and small clusters during a 15 min incubation period. At 3 and 10 μg/ml anti-IgE, net secretion is reduced and the majority of receptors redistribute rapidly into clusters and large aggregates.

Organization of transcription and pre-mRNA splicing within the mammalian cell nucleus

1995 ◽  
Vol 53 ◽  
pp. 768-769
Author(s):  
D.L. Spector ◽  
S. Huang ◽  
S. Kaurin
Keyword(s):  
Rna Polymerase Ii ◽  
Cell Nucleus ◽  
Functional Organization ◽  
Mrna Splicing ◽  
Splicing Factors ◽  
Interchromatin Granule Clusters ◽  
Interchromatin Granule ◽  
Nuclear Regions ◽  
Relationship Of ◽  
Perichromatin Fibrils

We have been interested in the organization of RNA polymerase II transcription and pre-mRNA splicing within the cell nucleus. Several models have been proposed for the functional organization of RNA within the eukaryotic nucleus and for the relationship of this organization to the distribution of pre-mRNA splicing factors. One model suggests that RNAs which must be spliced are capable of recruiting splicing factors to the sites of transcription from storage and/or reassembly sites. When one examines the organization of splicing factors in the nucleus in comparison to the sites of chromatin it is clear that splicing factors are not localized in coincidence with heterochromatin (Fig. 1). Instead, they are distributed in a speckled pattern which is composed of both perichromatin fibrils and interchromatin granule clusters. The perichromatin fibrils are distributed on the periphery of heterochromatin and on the periphery of interchromatin granule clusters as well as being diffusely distributed throughout the nucleoplasm. These nuclear regions have been previously shown to represent initial sites of incorporation of 3H-uridine.

Locating Al in the DABCO catalyst before and after Al extraction

1990 ◽  
Vol 48 (4) ◽  
pp. 265-267
Author(s):  
Kathleen B. Reuter
Keyword(s):  
Active Site ◽  
Inverse Relationship ◽  
Transverse Direction ◽  
Reaction Rate ◽  
Acid Phosphate ◽  
Fracture Surfaces ◽  
Al Content ◽  
Before And After ◽  
Relationship Of

The reaction rate and efficiency of piperazine to 1,4-diazabicyclo-octane (DABCO) depends on the Si/Al ratio of the MFI topology catalysts. The Al was shown to be the active site, however, in the Si/Al range of 30-200 the reaction rate increases as the Si/Al ratio increases. The objective of this work was to determine the location and concentration of Al to explain this inverse relationship of Al content with reaction rate.Two silicalite catalysts in the form of 1/16 inch SiO2/Al2O3 bonded extrudates were examined: catalyst A with a Si/Al of 83; and catalyst B, the acid/phosphate Al extracted form of catalyst A, with a Si/Al of 175. Five extrudates from each catalyst were fractured in the transverse direction and particles were obtained from the fracture surfaces near the center of the extrudate diameter. Particles were also obtained from the outside surfaces of five extrudates.

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