flexural torsional buckling of thin walled columns

... because of the formation of 5-member ring structures [32] In present case, the formation of bambooshaped CNTs is more possibly attributed to the doping of nitrogen into CNTs because of the easy ... different temperatures: a 780°C, b 820°C, c 860°C Fig The thin- walled index (TWI, defined as the ratio of inner diameter and wall thickness of a CNT) of the CNTs produced at different temperatures: a ... Field-emission values of different samples are shown in Table It can be seen that thin- walled open-ended aligned 123 946 Fig Morphology of the as-grown products: a photograph of the products grown...

Ngày tải lên: 21/06/2014, 18:20

... 2.07 [)! buckling is by flexure, whereas below thls line buckling is by torsion Figure 18.24 Modes of buckling of a cruciform strut 454 Buckling of columns and beams 18.16 Lateral buckling of a ... buckling of a cruciform strut With a knowledge of the torsional and flexuralbuckling loads of a cruciform strut, we can estimate the range of struts, we can estimate the range of struts for which buckling ... q h x d A a Torsional buckling of a cruciform strut 45 Figure 18.23 Torsional buckling of a cruciform column The geometrical quantity s,h x2dA is the polar second moment of area of the cross-section...

Ngày tải lên: 08/04/2014, 11:27

... years Thin Films - A Historical Perspective Thin- film technology is simultaneously one of the oldest arts and one of the newest sciences Involvement with thin films dates to the metal ages of antiquity ... many years of experience teaching and advising graduate students at Stevens Institute of Technology, Professor Ohring has been the coordinator of an on-premises, M.S degree program offered by ... Several of these graduates have gone on to acquire Ph.D degrees The combination of teaching, research, and industrial involvement has provided Professor Ohring with a broad perspective of thin film...

Ngày tải lên: 05/03/2014, 17:20

... crucial importance of deposition technology is the fabrication of semiconductor devices, an industry that is totally dependent on the formation of thin solid films of a variety of materials by deposition ... billions of dollars • A large fraction of the fabricator’s cost is the cost of manufacturing equipment This book is a detailed account of the processes performed by the equipment 1.1 Role of Cleanliness ... and appreciation of these systems Key properties and areas of application of industrially important materials created by thin film deposition processes are described Extensive use of references,...

Ngày tải lên: 28/04/2014, 10:53

... nm The height profiles indicate the presence of an SWCNT bundle Radial breathing modes In the RBM region of the TERS spectra three or four different RBMs are observed at each of the marked positions ... depicted in Figure by the y-axis of the green ellipse The heights and the full widths at half maxima (FWHM) of the peaks after a Lorentzian fit of the height profiles are summarized in Table The ... the presence of an SWCNT Figure Left-hand side: Height profiles of the seven measured positions along an SWCNTs bundle Right-hand side: AFM topography together with an approximation of the far-field...

Ngày tải lên: 21/06/2014, 05:20

... sodium azide in the presence of ammonium chloride, as shown in Figure Typically, a solution of POSS (1.0 g 3.19 mmol) in tetrahydrofuran (THF) (5 ml) was added to a solution of sodium azide (208 mg ... molecule onto MWNTs Page of was precipitated into 200 ml of water and the product was vacuum dried at 40°C for 60 h The yield of azidefunctionalized POSS obtained was 85% Synthesis of MWNT-POSS nanohybrid ... mmol) solution of POSS-N3 in 15 ml of DMF The flask was equipped with a magnetic stirrer bar with a reflux condenser 162 mg (0.85 mmol) of copper iodide and 6.4 g (42.5 mmol) of 1,8-diazabicyclo[5,4]undecene-7-ene...

Ngày tải lên: 21/06/2014, 05:20

... rarely observed, in the very thin part of the specimen However, the repetitive observations of the same XTEM specimen after a series of sequential small duration of ion milling allow us to observe ... coming from the graphitic like lattice planes, in Page of the walls of the nanotube This small contrast can be observed only in the very thin areas of the XTEM specimen, similar to the case presented ... the top surface of the MWCNT-SiN layer, and the presence of the few nm thin Cr layer Looking at the XTEM specimen at higher magnification it was possible to observe the presence of the MWCNT in...

Ngày tải lên: 21/06/2014, 06:20

... diameter of the nanorods varies from 140 to 180 nm, and the length is of several hundreds of nanometers Figure presents the temperature dependence of the dc conductivity of thin films of a- GaxSe100-x ... well-established knowledge of the electrical and optical properties of GaSe thin films, in this paper, we report the results on electrical and optical measurements of amorphous thin films of GaSe nanorods ... system, the value of pre-exponential factor (r0) is of the order of 101 X-1 cm-1 On the basis of this value of r0, it is suggested that the conduction is taking place in the band tails of localized...

Ngày tải lên: 21/06/2014, 17:20

... this allows a substantial simplification of the equations describing the flow of the thin paint film 2.1 Physical model Here, we consider the leveling of a thin incompressible film deposited on an ... Fourier transform of a product of functions in physical space is the convolution of the Fourier transforms of the functions Numerically, care has to be taken when the Fourier transform of the product ... Piezanowski Rheology of thin films from flow observations In preparation 12 D.J Benney Long waves on liquid films J.Math.Phys., 45:150 – 155, 1966 13 V.Y Shkadov Wave flow regimes of a thin layer of viscous...

Ngày tải lên: 21/06/2014, 17:20

... the influence of growth temperature on the purity of prepared tube samples, we give the curve (Fig 4) showing the dependence of ID/IG on the growth temperature From Fig 4, two kinds of ID/IG distributions ... in the results and are coated by plenty of amorphous carbons Conclusions A temperature window of SWCNTs growth by catalytic chemical vapor deposition of CH4 over Mo-Fe/MgO catalyst has been studied ... the self-decomposition of CH4 The temperature window of SWCNTs efficiently growth is between 800 and 950 °C, and the optimum growth temperature is about 900 °C Fig Influence of growth temperature...

Ngày tải lên: 22/06/2014, 00:20

... temperature of weight loss of the P-MWNTs occurred at 600 °C while that of the F-MWNTs occurred at 460 °C The early weight loss of the F-MWNTs could be attributed to the stripping off of aromatic ... the effect of collector speed on the morphologies of the nanofibers and the crystal structures of the nylon-6 In the present study, we employed the aromatic amine functionalized multi -walled nanotubes ... electrical, mechanical, and physical properties of the polymeric materials can be improved by incorporating a minute amount of CNTs The dispersion and alignment of CNTs, however, have been problematic...

Ngày tải lên: 22/06/2014, 01:20

... on the surface of the tubes The ratio of H2 to O2 is critical to the process because it directly correlates with the composition of the generated cations In this study, the effect of gas composition ... and b TEM images of the pristine MWCNTs, c SEM, and d TEM images of ECR-plasma-treated MWCNTs with exposure under H2/O2 gas compositions of 40/10 (sccm/sccm) Fig XPS C 1s spectra of the pristine ... H2/O2 ratio of 25/25 (sccm/sccm), the highest concentration of Nanoscale Res Lett (2009) 4:234–239 237 Fig XPS C 1s spectra of the pristine MWCNTs and the ECRplasma-treated MWCNTs after of exposure...

Ngày tải lên: 22/06/2014, 01:20

... to b1, and TR2 to a2 An example of each type of BC2N nanotubes is given in Fig 1b–f Fig 2D projections of zigzag BC2N nanotubes (ZZ-1) z is a glide plane lack of horizontal symmetry axis/plane, ... symmetries at the C point of the 12 N (N is the number of unit cells in the tube and N = n for ZZ-1 BC2N nanotubes) of phonons in ZZ-1 BC2N nanotubes and the number of Raman- or IR-active modes, ... common divisor of 2n þ m and 2m þ n ; d is 0 the greatest common divisor of n and m ; SN/d and SN are the screw-axis operations with the orders of N/d and N, respectively The point group of the line...

Ngày tải lên: 22/06/2014, 01:20

... scanning in the 2h range of 10–90°, in steps of 0.05° X-ray diffraction pattern of DyNi2 alloy shows the formation of single phase with a C 15 type cubic structure XRD pattern of as-prepared CNTs ... yield of MWNT is defined as the ratio of weight loss between 500 °C and 700 °C to the weight that remain at 850 °C This is a measure of the ratio of the weight gain by MWNT to the weight of the ... burning of MWNT Final residual weight of 1.5% was obtained for the purified MWNT The purity of the purified sample is about 95% whereas the TG curve for the as-grown MWNT indicates a purity of only...

Ngày tải lên: 22/06/2014, 18:20

... years Thin Films - A Historical Perspective Thin- film technology is simultaneously one of the oldest arts and one of the newest sciences Involvement with thin films dates to the metal ages of antiquity ... many years of experience teaching and advising graduate students at Stevens Institute of Technology, Professor Ohring has been the coordinator of an on-premises, M.S degree program offered by ... Several of these graduates have gone on to acquire Ph.D degrees The combination of teaching, research, and industrial involvement has provided Professor Ohring with a broad perspective of thin film...

Ngày tải lên: 27/06/2014, 06:20

... years Thin Films - A Historical Perspective Thin- film technology is simultaneously one of the oldest arts and one of the newest sciences Involvement with thin films dates to the metal ages of antiquity ... many years of experience teaching and advising graduate students at Stevens Institute of Technology, Professor Ohring has been the coordinator of an on-premises, M.S degree program offered by ... Several of these graduates have gone on to acquire Ph.D degrees The combination of teaching, research, and industrial involvement has provided Professor Ohring with a broad perspective of thin film...

Ngày tải lên: 27/06/2014, 17:20

Ngày tải lên: 23/07/2014, 13:52

... to pilliation of these organisms, as well as a specific uptake sequence, within the genome of these bacterium [1] The use of mutations for the study of the capsular polysaccharide of N meningitidis ... transformation process of this bacterium is unknown This work aimed at the use of multi -walled carbon nanotubes (MWCNT) for the study of the nanostructures action on the transformation process of meningococci, ... at the action of MWCNT in the transformation of serogroup C N meningitidis against two different DNA obtained from isogenic mutants of this microorganism Methods Synthesis of multi -walled carbon...

Ngày tải lên: 11/08/2014, 08:20

... years Thin Films - A Historical Perspective Thin- film technology is simultaneously one of the oldest arts and one of the newest sciences Involvement with thin films dates to the metal ages of antiquity ... many years of experience teaching and advising graduate students at Stevens Institute of Technology, Professor Ohring has been the coordinator of an on-premises, M.S degree program offered by ... Several of these graduates have gone on to acquire Ph.D degrees The combination of teaching, research, and industrial involvement has provided Professor Ohring with a broad perspective of thin film...

Ngày tải lên: 11/08/2014, 20:21