x ray diffraction studies of chitin chitosan and their derivatives

... carbide XRD : x- ray diffraction HR-XRD : High-resolution synchrotron x- ray diffraction RSM : Reciprocal space mapping PLM : Polarized light microscope xx FWHM : Full-width-at-half-maximum ε’ ... et al [24] and the phenomenological theoretical work of Vanderbilt and Cohen [25] Subsequently, extensive structural studies by means of high-resolution synchrotron x- ray and neutron diffractions ... evidence of R micro- and nanotwins These diffraction patterns indicate the possible coexistence of {100}-type and {110}-type R* (see text for details) Fig 7.7 (a) ZFH ε’ and (b) ZFH J of unpoled...

Ngày tải lên: 14/09/2015, 08:40

... Synchrotron x- ray diffraction of higher energy, being 18 keV, revealed similar penetration depth in PZN-8%PT sample [32] Meanwhile, using synchrotron x- ray diffraction at 10.7 keV, 32 keV, and 67 ... µm, 59 µm, and 412 µm of a PZN sample [57] This suggests a nonlinear relation between the x- ray energy and the penetration depth despite similar test samples were used Whether the x- ray diffraction ... structure of the thin surface layer The experimental results pertaining to the origin of the broad lower 2θ peak adjacent to the major (002)R peak and the effects of surface layer on x- ray diffraction...

Ngày tải lên: 14/09/2015, 08:40

... the x- ray diffraction patterns (Figures 5.11a, c, and e) As a result, the polished surface can hardly reveal any useful structural information of the crystals hence unsuitable for x- ray diffraction ... x- ray diffraction study 5.3.2 Electrical resistance 73 The effect of room-temperature poling on the stability of the deformed surface layer was also investigated Figure 5.12 shows the XRD profiles ... treatment 5.4 (a) Summary of main observations The cause for the occurrence of the extremely broad lower 2θ peak adjacent to the main (002)R peak in standard XRD profiles of (001)-orientated PZN-PT...

Ngày tải lên: 14/09/2015, 08:40

... in the x- ray profile following any direction of polishing, suggesting that the surface phase is always present regardless of the direction and/ or mode of polishing This behavior can be explained ... treatments The heating and cooling rates used were 1.5 ºC/min Figure 5.9 shows the (002) XRD profiles of the differently annealed PZN-4.5%PT samples and the (002) XRD profile of the as-polished sample ... tilted by an angle of 45° and again polished back and forth in the new direction After the second polishing, the earlier set of domains disappeared and was replaced by a new set of elongated domains...

Ngày tải lên: 14/09/2015, 08:40

... streaking effect of untilted T nanodomains, (i) streaking effects of tilted T nanodomains, and (l) combined diffraction patterns of T micro/nanodomains of all configuration 84 result of their nano-size ... d4, and d6, d7 being the bm diffraction) + T (d2 and d5), (b) T (d2 and d5) + T* (d1, d3, d4 and d6) + R (d7), or (c) T (d2 and d5) + T* (d1, d3, d4, d6, and d7, d7 being the T nanotwin diffraction ... Subtle changes of the various diffractions with increasing temperature indicate that these diffractions is a mixture of R phase and the coherent effects of (100)T-(001) T nanodomain diffractions...

Ngày tải lên: 14/09/2015, 08:40

... projection of coexistence of the {100}-type and {110}-type R nanotwins onto the (002) RSM (b) The projection of the coexistence of R micro- and nanotwins onto (002) RSM 112 coexistence of R micro- and ... {100}-type and/ or {110}-type R microtwin domains, a result of the large diffraction width associated with the fine domain structure and the extreme compliant nature of the R phase The diffraction ... R peak while (b) shows evidence of R micro- and nanotwins These diffraction patterns indicate the possible coexistence of {100}-type and {110}-type R* (see text for details) 114 7.4 Thermally-induced...

Ngày tải lên: 14/09/2015, 08:40

... of the {100}-type and/ or {110}-type R micro- and/ or nanotwin domains, a result of the large diffraction half-width associated with the fine domain structure and the extreme compliant nature of ... Room temperature HR-XRD (002) RSMs of unpoled (annealed) (a) and (b) PZN-7%PT, and (c) and (d) PZN-8%PT single crystals 127 sample of PZN-7%PT and PZN-8%PT, respectively, but of the same wafers ... 6.1 gives the relationships between the m axes and the pc axes of the various M phases and the O phase Judging from the nature of splitting, these diffraction peaks in Figure 8.1(d), say, may...

Ngày tải lên: 14/09/2015, 08:40

... (d1, d2, d3, d4, and d6) + T (d2 and d5), or (c) T* (i.e., d1, d3, d4, and d6) + T (i.e., d2 and d5) We may rule out possibilities (a) and (b) as transformations of the type MB-C and MC-C are not ... located at 2θ ≈ 44.90° and lying out of the ω = 0° plane indicates that a small amount of the T phase may be present The room temperature structure of PZN-7%PT is thus a mixture of (R+Tσ) in which ... and d6 lie in the ω = 0° plane, the remaining peaks lie out of the ω = 0° plane Upon increasing the temperature to 115 °C, six peaks were diffracted (Figure 8.13e) Of the six peaks, d1, d2, and...

Ngày tải lên: 14/09/2015, 08:40

... entire MPB (standard + extended) region where (R+T) coexist, the crystal exhibits extremely high piezoelectric properties This suggests that the presence of (R+T) phase mixture in the form of micro/nanotwin ... of the {110}-type R nanotwins if the diffraction is of considerably smaller FWHM and lies in the ω = 0°, or (c) the convoluted peak of both {100}-type and {110}-type R micro- and nanotwin mixture ... these crystals is thus the R phase of micro/nanotwin structure Samples showing similar RSMs were ground into powder of

Ngày tải lên: 14/09/2015, 08:40

... transformation in relaxor single crystals occurs over a temperature range, manifested by the coexistence of R* and T* domains, a string of thermal current signals, and continued degradation of KT and k31 The ... the x- axis Both the KT and k31 of PZN-4.5%PT started to degrade after it was heated to 105 ºC 174 domains are parallel to the E-field direction which is normal to the fractured surface being x- rayed ... HR-XRD results suggest TR-T ≅ 100-135 °C for [001]-annealed -and- poled PZN-4.5%PT and 95-115 °C for [001]-annealed-andpoled PZN-7%PT single crystals 175 Table 9.2 TDP, TR-T(L), and TR-T(U) of...

Ngày tải lên: 14/09/2015, 08:40

... diagram of the ferroelectric relaxor (1 -x) Pb(Mg1/3Nb2/3)O3-xPbTiO3, Phys Rev B, 66, p 054104 2002 36 Bai, F., N Wang, J Li, D Viehland, P M Gehring, G Xu and G Shirane X- ray and neutron diffraction ... Shrout X- ray diffraction and phenomenological studies of the engineered monoclinic crystal domains in single crystal relaxor ferroelectric, J Appl Phys., 87, p 8159-8164 2000 70 Yin, J and W Cao ... tensors and matrices p 20-24, 78-81, Oxford University Press, USA 1957 93 Cao, H., J Li, D Viehland and G Xu Fragile phase stability in (1- x) Pb(Mg1/3Nb2/3O3)-xPbTiO3 crystals: a comparison of [001]...

Ngày tải lên: 14/09/2015, 08:40

... mixtures of phospholipid and cholesterol Small-angle X- ray scattering intensity patterns of binary mixtures of (A) brainSM and (B) egg-PtdCho with the indicated mol% cholesterol at 37 °C (C) and ... Synchrotron X- ray diffraction measurements X- Ray diffraction measurements were performed on beamline 2.1 at the Daresbury Laboratory The X- ray wavelength was 0.154 nm with a beam geometry of $ 0.2 ... egg-PtdCho peaks of the mixture shown in Fig The d-spacing of peak in Fig 4B coincides closely with bilayers formed from a binary mixture of egg-PtdCho and proportions of cholesterol of $ 25 mole%...

Ngày tải lên: 15/03/2014, 23:20

... characterized by a consensus 23-residue sequence of GX5EX7REUXEEXGU termed the Nudix motif (U is a bulky residue and X is any residue), which is the Mg2+ binding site and the 27 a Dcp2 P593780 GKIDKDESDVDCAIREVYEETGF ... decapped by Dcp1/Dcp2 complex, followed by 5’ exonuclease Xrn1 digestion Alternatively, the deadenylated transcript can be degraded by the 3’ exonuclease complex of exosome And the resulting short ... cerevisiae 5’ decay complex Budding yeast 5’ decay complex are composed of 5’-3’ exonuclease Xrn1p, decapping enzyme Dcp2p/Dcp1p, DEADbox helicase Dhh1p, Lsm1-7, Edc3p and other auxiliary RNA-binding...

Ngày tải lên: 14/09/2015, 12:28

... fixed value of t variation of E, (a) with t at a fixed value of x and (b) with x at PKOPERTIES OF X- RAYS [CHAP film arbitrary units, such as the degree of blackening of a photographic to the x- ray ... the exact relation The region between netic X X X bemg lkX= 1.00202A worth while to review briefly some properties of electromagnetic Suppose a monochromatic beam of x- rays, i.e., x- rays of a ... understanding of the radiation used, because it was not until 1912 that the exact nature of x- rays was established In that year the phenomenon of x- ray diffraction by crystals was discovered, and...

Ngày tải lên: 29/03/2014, 11:20

... (see Figure and text for details) where SX denotes the size of the largest cluster of type X, xX is the number fraction of each structure type ( X xX = 1), and fX (n) is the value of log-normal ... function of the structure type and cluster size is aX (n) = X + X − X × π + atan n0 − n /wX X , π + atan n0 − /wX X (5) Table 1: Values of parameters used in (6) to compute synthetic XRD intensity ... distribution fX (n) = exp − sX /2 2π X sX exp − log n − log X 2s2 X , (4) M Ladisa et al with mode X and logarithmic width sX Structural distances for the different structure types X are generally...

Ngày tải lên: 22/06/2014, 20:20

Ngày tải lên: 19/04/2016, 11:32

... piles of cabbage and cauli-flowers, the rows of tin ware and copper saucepans, the heaps of maccaroni and pastes, of spices and drugs; the garlands of onions and red peppers and piles of apples; ... re-writing it, and the poems of Walther, of Gottfried, of Wolfram, of Ulrich, and of Tannhọuser, full as they are of references to stories of the Carolingian and Arthurian cycles, nay, to Antique and Oriental ... been expeditiously emptied of all its contents, to make room for kingdoms of Gaul, of Rome, of the Firm Island, of Sobradisa, etc., which are less like the Land West of the Moon and East of the...

Ngày tải lên: 21/02/2014, 21:20

... and overall text quality We would expect that the presence of disfluent sentences in text will make it appear less well written Five annotators had previously assess the overall text quality of ... stretches of text But even in human written text, the presence of more verbs can make a difference in fluency (Bailin and Grafstein, 2001) Consider the following two sentences: Table 1: Distribution of ... the content of the sentence compared to a human gold-standard Yet, the assessments of the two aspects were often the same—readability/fluency of the sentence is important for understanding the...

Ngày tải lên: 22/02/2014, 02:20

... II (PSII) of C reinhardtii [16] We now report the expression of His- and Strep-tagged plant PSI Results A series of cassettes containing tagged variants of the full-length precursor of Arabidopsis ... topology of cyanobacterial PSI-K, as determined by X- ray crystallography of Synechococcus elongatus PSI [11,12] The crystal structure placed cyanobacterial PSI-K at the outside edge of the complex, ... to determine the topology of PSI-G and to test the feasibility of rescuing Arabidopsis PSI complexes lacking PSI-G with tagged constructs Successful introduction of a hexa-histidine (His)- or Strep-tagged...

Ngày tải lên: 07/03/2014, 21:20

... T, Jarvest RL & Sanderson MR (1998) Exploring the active site of herpes simplex virus type-1 thymidine kinase by X- ray crystallography of complexes with aciclovir and other ligands Proteins 32, ... in the P loop, and the substrates are at nearly identical positions in the active site The interactions of the deoxyribose and the base are identical to those of the dT complex, except for the ... BVDU and brivudine monophosphate (BVDUMP) in the HSV-1-TK + BVDU complex [19] and the VZV + BVDUMP and ADP complex [20] Zidovudine (AZT) is a potent inhibitor of HIV replication in vitro and at...

Ngày tải lên: 16/03/2014, 06:20