Synthesis and structure of stable 1,2-diaryldisilyne

2010 ◽  
Vol 82 (3) ◽  
pp. 603-612 ◽  
Author(s):  
Takahiro Sasamori ◽  
Joon Soo Han ◽  
Koji Hironaka ◽  
Nozomi Takagi ◽  
Shigeru Nagase ◽  
...  
Keyword(s):  
Triple Bond ◽  
Theoretical Calculations ◽  
Structural Features ◽  
Stable Compound ◽  
Theoretical Results ◽  
Bond Character ◽  
Methyl Phenyl

A novel 1,2-diaryldisilyne, BbtSi≡SiBbt (Bbt = 2,6-bis[bis(trimethylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl), was synthesized as a stable compound by reduction of the corresponding 1,2-dibromodisilene, Bbt(Br)Si=Si(Br)Bbt. The spectral and structural features of this first stable 1,2-diaryldisilyne are revealed, and the Si≡Si triple-bond character is evaluated with the aid of detailed theoretical calculations. The triple-bond characters of BbtSi≡SiBbt and BbtGe≡GeBbt are compared based on experimental and theoretical results.

MANUFACTURE INVESTIGATION OF CARTRIDGE WITH BOTTOM-MOST PART FLANGE BY DIRECT EXTRUSION WITH COUNTERPUNCH. REPORT 18. EXPERIMENTAL CHECK OF THEORETICAL RESULTS FOR DIFFERENT HOLLOW RADIUSES AND BOTTOM-MOST PART THICKNESSES

2020 ◽  
Vol 0 (9) ◽  
pp. 16-23
Author(s):  
A. L. Vorontsov ◽  
◽  
I. A. Nikiforov ◽  
Keyword(s):  
Strain Hardening ◽  
Theoretical Calculations ◽  
High Accuracy ◽  
Geometric Parameters ◽  
Strength Characteristics ◽  
Experimental Check ◽  
Hardening Material ◽  
Direct Extrusion ◽  
Theoretical Results

The results of an experimental check of the obtained theoretical formulae allowing us to determine the most important parameters of extrusion cartridges with a counterpunch for different hollow radiuses and bottom-most part thicknesses are presented. Characteristics of used tools, geometric parameters of extrusion experiments, strength characteristics of deformed materials and lubricants are described in detail. Both strain-hardening material and strain-unhardening material were studied. Methodology of the theoretical calculations is demonstrated in detail. High accuracy of the obtained design formulae was confirmed.

scholarly journals Frequency Response Evaluation of Guitar Bodies with Different Bracing Systems

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 795
Author(s):  
Mircea Mihălcică ◽  
Mariana D. Stanciu ◽  
Sorin Vlase
Keyword(s):  
Structural Features ◽  
Dynamic Force ◽  
Classical Guitar ◽  
Elastic Symmetry ◽  
Frequency Responses ◽  
Points Of View ◽  
Coupled Plates ◽  
Natural Composite ◽  
Theoretical Results ◽  
Symmetric Systems

Wood is a natural composite, having a porous structure, with a complex elastic symmetry specific to orthotropic solid, influenced by three mutually perpendicular planes of elastic symmetry. The classical guitar is obtained from different wooden species, each of them having their own elastic properties and, as a whole, forming a lignocellulosic composite structure. Generally, some constructive parts of the classical guitar body are based on symmetry, starting from the structural features of wooden plates, which are symmetrically cut, and some patterns of the stiffening bars. The other elements, such as the strings system, are not symmetric. This study aims to evaluate the frequency responses of the guitar body as a symmetrical mechanical system from constructive points of view. Because theoretical results (analytic and numeric) regarding the symmetrical systems cannot be applied to quasi-symmetric systems, the dynamic response was analyzed from experiments performed on four types of classical guitar body (without neck), different from each other by the pattern of stiffening bars placed inside of the top plate. The experiments were performed using a Brüel&Kjær mini-shaker to excite the structure, and the signal was captured with accelerometers. The symmetric behavior of coupled plates from the guitar body was noticed in the case of an applied dynamic force of 110 Hz and 440 Hz, but in the case of 146 Hz, 588 Hz, 720 Hz, quasi skew symmetrical modes were recorded.

scholarly journals IV. On the dynamical theory of incompressible viscous fluids and the determination of the criterion

1895 ◽  
Vol 186 ◽  
pp. 123-164 ◽  
Keyword(s):  
Singular Solution ◽  
Physical State ◽  
Theoretical Calculations ◽  
Equations Of Motion ◽  
Dynamical Theory ◽  
Viscous Fluids ◽  
Linear Functions ◽  
Incompressible Viscous Fluids ◽  
Theoretical Results

1. The equations of motion of viscous fluid (obtained by grafting on certain terms to the abstract equations of the Eulerian form so as to adapt these equations to the case of fluids subject to stresses depending in some hypothetical manner on the rates of distortion, which equations Navier seems to have first introduced in 1822, and which were much studied by Cauchy and Poisson) were finally shown by St. Venant and Sir Gabriel Stokes, in 1845, to involve no other assumption than that the stresses, other than that of pressure uniform in all directions, are linear functions of the rates of distortion, with a co-efficient depending on the physical state of the fluid. By obtaining a singular solution of these equations as applied to the case of pendulums in steady periodic motion, Sir G. Stokes was able to compare the theoretical results with the numerous experiments that had been recorded, with the result that the theoretical calculations agreed so closely with the experimental determinations as seemingly to prove the truth of the assumption involved. This was also the result of comparing the flow of water through uniform tubes with the flow calculated from a singular solution of the equations so long as the tubes were small and the velocities slow. On the other hand, these results, both theoretical and practical, were directly at variance with common experience as to the resistance encountered by larger bodies moving with higher velocities through water, or by water moving with greater velocities through larger tubes. This discrepancy Sir G. Stokes considered as probably resulting from eddies which rendered the actual motion other than that to which the singular solution referred and not as disproving the assumption.

scholarly journals DNA structure change induced by guanosine radicals – a theoretical and spectroscopic study

2018 ◽  
Author(s):  
J. Kobierski ◽  
E. Lipiec
Keyword(s):  
Dna Damage ◽  
Theoretical Calculations ◽  
Direct Interaction ◽  
Dna Structure ◽  
Structure Change ◽  
Proton Radiation ◽  
Dna Structures ◽  
Spectral Changes ◽  
Dna Strand ◽  
Theoretical Results

AbstractProton radiation therapy is one of the newest and most promising methods used in modern oncology. Nonetheless, the dissemination of that method may result challenging. This is partially due to the fact that the mechanism of DNA damage induced by protons, which is one of the ways proton radiation interacts with tissues, has not been fully understood yet. It is well known that ionizing radiation especially ions such as protons may directly damage DNA but it also causes the formation of radicals, which may lead to even more serious damage of the DNA sugar-backbone than direct interaction with charged ion. In this article we focus on the influence of guanine radicals on the DNA structure, namely the conformation and stability of the DNA strand. We present the theoretical results of the optimization calculations of DNA structures with guanine radical-adenine pairs as well as calculated Raman spectra. By combining theoretical calculations with the experimental spectra we were able to explain molecular modifications of the DNA sugar-backbone affected by guanine radicals formed upon radiation exposure, which lead to spectral changes between spectra of control and irradiated DNA. Thus we established a pathway of the formation of DNA damage caused by protons.

scholarly journals 3-Phenyl-N,N,N′,N′-tetramethyl-1-ethyne-1-carboximidamidium bromide

2012 ◽  
Vol 68 (6) ◽  
pp. o1812-o1812 ◽  
Author(s):  
Ioannis Tiritiris ◽  
Willi Kantlehner
Keyword(s):  
Double Bond ◽  
Title Compound ◽  
Triple Bond ◽  
Positive Charge ◽  
Bond Distance ◽  
Double Bond Character ◽  
Acetylenic Bond ◽  
Compound C ◽  
Bond Character

The reaction of 3,3,3-tris(dimethylamino)-1-phenylprop-1-yne with bromine in pentane yields the title compound, C13H17N2 +·Br−. The acetylenic bond distance [1.197 (2) Å] is consistent with a C[triple-bond]C triple bond. The amidinium C=N bonds [1.325 (2) and 1.330 (2) Å] have double-bond character and the positive charge is delocalized between the two dimethylamino groups.

scholarly journals Comparative analysis of the trypanocidal activity and chemical properties of E-lychnophoric acid and its derivatives using theoretical calculations

2005 ◽  
Vol 30 (3) ◽  
pp. 37-45 ◽  
Author(s):  
A. F. C. Alcântara ◽  
D. Silveira ◽  
E. Chiari ◽  
A. B. Oliveira ◽  
J. E. Guimarães ◽  
...  
Keyword(s):  
Theoretical Calculations ◽  
Geometry Optimization ◽  
Chemical Properties ◽  
Atomic Charge ◽  
Trypanocidal Activity ◽  
Orbital Population ◽  
Theoretical Results ◽  
Conformational Distribution ◽  
And Chemical Properties ◽  
Endocyclic Bond

E-Lychnophoric acid 1, its derivative ester 2 and alcohol 3 killed 100% of trypomastigote blood forms of Trypanosoma cruzi at the concentrations of 13.86, 5.68, and 6.48 µg/mL, respectively. Conformational distribution calculations (AM1) of 1, 2 and 3 gave minimum energies for the conformers a, b, c, and d, which differ from each other only in the cyclononene ring geometry. Calculations (DFT/BLYP/6-31G*) of geometry optimization and chemical properties were performed for conformers of 1, 2, and 3. The theoretical results were numerically compared to the trypanocidal activity. Calculated values of atomic charge, orbital population, and vibrational frequencies showed that the C-4-C-5 pi-endocyclic bond does not affect the trypanocidal activity of the studied compounds. Nevertheless, the structure of the group at C-4 strongly influences the activity. However, the theoretical results indicated that the intra-ring (C-1 and C-9) and pi-exocycle (C-8 and C-14) carbons of caryophyllene-type structures promote the trypanocidal activity of these compounds.

Forward Kinematics Simulation for a Surgical Robot Using CATIA 5

2015 ◽  
Vol 22 ◽  
pp. 21-28
Author(s):  
Shao Gang Liu ◽  
Farah Edris
Keyword(s):  
Minimally Invasive Surgery ◽  
Theoretical Calculations ◽  
Surgical Robot ◽  
Forward Kinematics ◽  
Kinematic Simulation ◽  
Kinematics Simulation ◽  
Robot Tracking ◽  
Simulation Results ◽  
Forward Kinematic ◽  
Theoretical Results

Forward Kinematic simulation of a 6 DOF surgical robot tracking a path through the constraint of the Remote Center of Motion point (RCM) is developed in this paper. Theoretical calculations of the forward kinematics are analyzed by solving the configuration kinematic equations of the robot. CAD prototype of the surgical robot and the patient are created using CATIA5 part and assembly tools. The theoretical results are validated through a Kinematic simulation of CATIA kinematics. The simulation results confirm the usefulness of the six revolute joint robots in minimally invasive surgery (MIS) and the efficiency of using the power full CATIA5 software to simulate surgical robot, and checking the robot mechanism capability of doing surgical procedures.

Level density model effects on the production cross-section calculations of some medical isotopes via (α, xn) reactions where x = 1–3

2020 ◽  
Vol 35 (24) ◽  
pp. 2050202
Author(s):  
Mert Şekerci ◽  
Hasan Özdoğan ◽  
Abdullah Kaplan
Keyword(s):  
Cross Section ◽  
Production Cross Section ◽  
Nuclear Reactions ◽  
Theoretical Calculations ◽  
Production Cross ◽  
Level Density ◽  
Medical Application ◽  
Density Model ◽  
Level Density Models ◽  
Theoretical Results

Level density models have an undeniable importance for a better perception on the nature of nuclear reactions, which influences our life via various ways. Many novel and advanced medical application use radioisotopes, which are produced with nuclear reactions. By considering the connection between the level density models and the importance of theoretical calculations for the production routes of medically important isotopes, this study is performed to investigate the level density model effects on the production cross-section calculations of [Formula: see text]Zn, [Formula: see text]Ga, [Formula: see text]Kr, [Formula: see text]Pd, [Formula: see text]In, [Formula: see text]I and [Formula: see text]At radioisotopes via some alpha particle induced and neutron emitting reactions. For theoretical calculations; frequently used computation tools, such as TALYS and EMPIRE codes, are applied. Obtained theoretical results are then compared with the experimental data, taken from Experimental Nuclear Reaction Data (EXFOR) library. For a better interpretation of the results, a mean weighted deviation calculation for each investigated reaction is performed in addition to a visual comparison of the graphical representations of the outcomes.

Absolutmessung der kontinuierlichen Strahlung des Heliums im Lichtbogen von λ = 109 bis 540 nm / Measurement of the Helium Continuum Radiation from λ = 109 to 540 nm in an Arc Plasma

1980 ◽  
Vol 35 (8) ◽  
pp. 808-819 ◽  
Author(s):  
P. Thoma
Keyword(s):  
Energy Balance ◽  
Theoretical Calculations ◽  
Continuum Emission ◽  
Kinetic Temperature ◽  
Arc Plasma ◽  
Plasma Parameters ◽  
Continuum Radiation ◽  
Theoretical Results ◽  
Helium Emission ◽  
Good Agreement

Abstract Absolute helium emission coefficients have been measured from 540 nm down to 109 nm in the near vuv. The radiation originates from the axis of a cylindrical He-arc of 2 mm ∅ at one atmosphere with electron temperatures between 25000 K and 26500 K. The electron densities range from 3.0 · 1016 cm-3 to 4.0 · 1016 cm-3 and have been determined independently from other plasma parameters by means of line shape measurements. The density of atoms and their kinetic temperature have been calculated from the energy balance of the electrons and Dalton's law. Comparison of the measured helium continuum emission coefficients with theoretical calculations in the wavelength range from 540 nm to 400 nm shows that, in this experiment, the radiation due to bremsstrahlung in the field of atoms must not be neglected. Taking into account this contribution very good agreement with theoretical calculations over the whole investigated spectral range from 540 nm down to 109 nm has been found. Thus the present experiment confirms the theoretical results for the photoionisation coefficients from the n = 2 and n = 3 levels. On the basis of these results the helium continuum radiation may be used for calibration purposes, which is of particular interest in the vuv.

PUNCHING CUPS WITH BOTTOM FLANGE BY DIRECT EXTRUSION WITH COUNTER-PUNCH. EXPERIMENTAL VERIFICATION OF THEORETICAL RESULTS ON HARDENING MATERIAL

2020 ◽  
pp. 17-24
Author(s):  
A. L. Vorontsov ◽  
I. A. Nikiforov
Keyword(s):  
Experimental Verification ◽  
Theoretical Calculations ◽  
High Accuracy ◽  
Geometric Parameters ◽  
Strength Characteristics ◽  
Bottom Flange ◽  
Hardening Material ◽  
Direct Extrusion ◽  
Theoretical Results

The results of an experimental verification of the obtained theoretical formulas on hardening material are presented, which make it possible to determine the most important parameters for extruding glasses with a counter-punch. The methods of theoretical calculations and the characteristics of the tools used, the geometric parameters of extrusion experiments, the strength characteristics of the wrought material, and its lubrication are described in detail. The high accuracy of the obtained calculation formulas is confirmed.

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