Many field, experimental, and theoretical studies have contributed greatly to our understanding of the occurrence and formation of deformation bands in porous granular materials, but questions remain regarding the mechanics of strain localization, and how the orientation, thickness and internal strain (shear relative to volume change) of deformation bands is influenced by loading history and evolving rock properties. Here we report on triaxial rock deformation experiments using a non-traditional sample geometry to investigate band formation across the brittle-ductile transition. Five-cm diameter cylinders of Berea sandstone were machined with a circular (8.77 cm radius) notch to form a dog-bone sample geometry. In triaxial compression, the sample geometry obviates end-effects without creating heterogeneous stress gradients that can influence localization. Samples were instrumented to measure local strains in the neck region and acoustic emissions (AE), and then shortened to failure at confining pressures of 50 to 250 MPa. Deformation bands formed at all conditions, and photo mosaics of the outer sample surface were used to determine the thickness and orientation of the bands. Band thickness increases from several to tens of mm thickness and the angle between the bands with the shortening axis changes from 35 to 80 degrees, as confining pressure increases from 50 to 250 MPa, respectively. Mechanical data, including local strain measurements through yield, were used to test theoretical models for the onset of localization and formation of deformation bands as an instability in the constitutive description of homogeneous deformation. Generally, theoretical predictions compare favorably with the observed onset of localization determined by marked changes in the AE rate, and are consistent with the formation of compacting shear bands at higher mean stress. Predictions of changes in band orientation with mean stress are largely consistent with observed trends, but deviate from the observed orientation by as much as twenty degrees.

Problem : How does Japanese company coordinate with its subsidiaries in Thai and Chinese markets? Purpose :  To describe organization structure of Japanese company as well as compare how headquarters coordinates with its subsidiaries in Thai and Chinese markets. Also, this thesis will give benefits for the academics and managers of other multinational corporations. Method :  Qualitative approach and comparative design are implemented in this thesis meanwhile secondary data from internet, documentary research  and primary data from semi-structured interview through telephone & email are used for collecting information. More importantly, Tokai Carbon is chosen as a case study to understand organization structure and its coordination between Japanese company and Thai & Chinese subsidiaries. Conclusion : The organization structure and coordination should  be concerned in multinational corporations. Tokai Carbon Co., Ltd. as a multinational Japanese company who runs business and establishes various subsidiaries in worldwide mostly centralizes power to headquarters. Also, Tokai Carbon Co., Ltd. applied means of formal and informal coordination in order to cooperate between Tokai Carbon Co., Ltd. (headquarters) and Thai Tokai Carbon Product Co., Ltd (Thai subsidiaries) & Tokai Carbon Tianjin Co., Ltd. (Chinese subsidiaries). With respect to formal and informal mechanisms, these two mechanisms are similarly implemented in collaboration between headquarters and Thai & Chinese subsidiaries. Nonetheless, there are a few differences on informal tools in form of lateral relations and socialization.

Discotic liquid crystals(DLCs) in this research absorb the light in visible region of spectrum, this characteristic is not found in rod-like liquid crystals. A majority of discotic liquid crystals form columnar mesophases probably due to intense £k-£k interactions of polyaromatic cores. £k-£k interactions are caused by intermolecular overlapping of p-orbitals in £k-conjugated systems, so they become stronger as the number of £k-electrons increases. Three new hexagonal columnar disctic liquid crystals 9-{11-[2,3,6,7-tetrakis(hexyloxy)dibenzo[a,c]phenazinylcarboxyalkyl]} have been successfully synthesized by covalently attaching carbazole moiety to a tetrakis (hexyloxy)dibenzo[a,c]phenazinyl core with an ester group containing different lengths of alkyl spacer having 3,6,and 11 carbon atoms. In order to set up a basic data base, we measure and analyze the discotic liquid crystals via various instruments.In addition, we also utilize both simulation systems of MMM and QMM to predict several molecular dynamics and properties such as: vibration, rotation, motion and heat of formation and so on.So we can see more depth inside how the concentration effects on the geometry structure arrangement of the discotic liquid crystals.

Improvements in process technology and design innovations have resulted in compact and cost effective digital baseband solutions. The radio part, however, has remained a bottleneck in terms of chip area and power consumption as the feature size of analog devices does not directly benefit from scaling. With the addition of yet more standards into emerging products, the requirements of future radios will extend over characteristic performance features into demands of programmable and reconfigurable hardware for radios covering multiple frequency bands. Hence, a guideline in the design of such radios is a large degree of hardware sharing. The thesis investigates the application of sigma-delta modulation to arising multistandard wireless radios. First, it reviews principles in wireless radios, such as selected modulation and access techniques. It also examines several communication standards of personal wireless radios as well as common receiver architectures for their implementation. This is followed by general considerations and background information about sigma-delta modulators. In the third and fourth chapter, implementations to two blocks of a wireless radio receiver system are suggested: An architecture for a frequency synthesizer and an implementation of an analog-to-digital converter. In the first contribution, the thesis develops a novel concept for frequency synthesis that is more suitable for multi-band, multi-standard radio architectures, achieving a large amount of hardware sharing among different wireless standards. As a second pillar, the thesis contributes with the design of a dual-standard sigma-delta modulator for data conversion within a radio receiver. Parts of the work concerning the dual-standard modulator are embodied in a granted swedish patent. / QC 20100830

The commensal Streptococcus gordonii expresses numerous surface adhesins with which it interacts with other microorganisms, host cells and salivary proteins to initiate dental plaque formation. However, this Gram-positive bacterium can also spread to non-oral sites such as the heart valves and cause infective endocarditis. One of its surface adhesins, Sgo0707, is a large protein composed of a non-repetitive N-terminal region followed by several C-terminal repeat domains and a cell wall sorting motif. Here we present the crystal structure of the Sgo0707 N-terminal domains, refined to 2.1 Å resolution. The model consists of two domains, N1 and N2. The largest domain, N1, comprises a putative binding cleft with a single cysteine located in its centre and exhibits an unexpected structural similarity to the variable domains of the streptococcal Antigen I/II adhesins. The N2-domain has an IgG-like fold commonly found among Gram-positive surface adhesins. Binding studies performed on S. gordonii wild-type and a Sgo0707 deficient mutant show that the Sgo0707 adhesin is involved in binding to type-1 collagen and to oral keratinocytes.

Large multi-component structures play an essential role in many crucial cellular processes. The morphogenetic pathway of the long, non-contractile tail of bacteriophage λ provides a superb paradigm for studying the assembly of macromolecular complexes. This thesis describes the structural and functional characterization of two λ tail proteins, gpU and gpV, with the aim of improving our understanding of phage tail assembly and evolution, while also providing a starting point to answering some of the fundamental questions surrounding the assembly and function of other supramolecular structures. Tail Terminator Proteins (TrPs) play an essential role in regulating the length of phage tails, and serve as the interaction surface for phage heads. To provide insight into the mechanisms by which TrPs exert their functions, I have determined the X-ray crystal structure of gpU, the TrP from phage λ, in its biologically relevant hexameric state. The gpU hexamer displays several flexible loops that are involved in head and tail binding. By comparing the hexameric crystal structure of gpU to its previously determined NMR solution structure I was able to identify large structural rearrangements in the protein, which are likely induced upon oligomerization. In addition, I have shown that the hexameric structure of gpU is very similar to the structure of a putative TrP from a contractile phage tail even though they display no detectable sequence similarity. This finding implies that the TrPs of non-contractile tailed phages are evolutionarily related to those of contractile-tailed phages. To determine the mechanism by which tail tubes self-assemble prior to termination, I have determined the NMR solution structure of the N-terminal domain of gpV (gpVN), the protein comprising the major portion of the phage λ tail tube. I found that approximately 30% of gpVN is disordered in solution and that some of these disordered regions are biologically important. Intriguingly, my gpVN structure is very similar to a previously solved tail tube protein from a contractile-tailed phage, once again suggesting an evolutionary connection between these two distinct tail types. A remarkable structural similarity is also seen to the hexameric structure of Hcp1, a component of the bacterial type VI secretion system. This finding, coupled with other similarities between phage and type VI secretion proteins support an evolutionary relationship between these systems. Using Hcp1 as a model, I proposed a mechanism for the oligomerization and polymerization of gpV involving several disorder-to-order transitions. Further supporting the importance of unstructured regions, I have shown that the unstructured linker between the N- and C-terminal domains of gpV is crucial for protein function and that a complete truncation of the C-terminal domain (gpVC) results in a 100-fold decrease in activity compared to full-length gpV (gpVFL). To provide insight into the role of gpVC, I determined its NMR solution structure and showed that it possesses an Ig-like fold, however the function of gpVC remains unknown. Interestingly, the gpVC structure revealed the location of two residues that when mutated were previously shown to either abrogate (G222D) or restore (G222D/P227L) function of gpVFL. In addition to being inactive, I demonstrated that the G222D mutation also exerts a temperature dependent dominant negative phenotype. My preliminary NMR data suggests that G222D causes gpVC to partially unfold and that this destabilized form of the domain interacts with gpVN in a region that is likely involved in both oligomerization and hexamer-hexamer interactions. To further our understanding of how these mutations exert their effect, I determined the NMR solution structure of gpVC-P227L. My structure reveals that the β7-β8 region of gpVC-P227L is altered compared to gpVC-WT and suggests that the conformational changes in gpVC-P227L may protect the domain from protein-folding defects induced by the G222D mutation.

Large multi-component structures play an essential role in many crucial cellular processes. The morphogenetic pathway of the long, non-contractile tail of bacteriophage λ provides a superb paradigm for studying the assembly of macromolecular complexes. This thesis describes the structural and functional characterization of two λ tail proteins, gpU and gpV, with the aim of improving our understanding of phage tail assembly and evolution, while also providing a starting point to answering some of the fundamental questions surrounding the assembly and function of other supramolecular structures. Tail Terminator Proteins (TrPs) play an essential role in regulating the length of phage tails, and serve as the interaction surface for phage heads. To provide insight into the mechanisms by which TrPs exert their functions, I have determined the X-ray crystal structure of gpU, the TrP from phage λ, in its biologically relevant hexameric state. The gpU hexamer displays several flexible loops that are involved in head and tail binding. By comparing the hexameric crystal structure of gpU to its previously determined NMR solution structure I was able to identify large structural rearrangements in the protein, which are likely induced upon oligomerization. In addition, I have shown that the hexameric structure of gpU is very similar to the structure of a putative TrP from a contractile phage tail even though they display no detectable sequence similarity. This finding implies that the TrPs of non-contractile tailed phages are evolutionarily related to those of contractile-tailed phages. To determine the mechanism by which tail tubes self-assemble prior to termination, I have determined the NMR solution structure of the N-terminal domain of gpV (gpVN), the protein comprising the major portion of the phage λ tail tube. I found that approximately 30% of gpVN is disordered in solution and that some of these disordered regions are biologically important. Intriguingly, my gpVN structure is very similar to a previously solved tail tube protein from a contractile-tailed phage, once again suggesting an evolutionary connection between these two distinct tail types. A remarkable structural similarity is also seen to the hexameric structure of Hcp1, a component of the bacterial type VI secretion system. This finding, coupled with other similarities between phage and type VI secretion proteins support an evolutionary relationship between these systems. Using Hcp1 as a model, I proposed a mechanism for the oligomerization and polymerization of gpV involving several disorder-to-order transitions. Further supporting the importance of unstructured regions, I have shown that the unstructured linker between the N- and C-terminal domains of gpV is crucial for protein function and that a complete truncation of the C-terminal domain (gpVC) results in a 100-fold decrease in activity compared to full-length gpV (gpVFL). To provide insight into the role of gpVC, I determined its NMR solution structure and showed that it possesses an Ig-like fold, however the function of gpVC remains unknown. Interestingly, the gpVC structure revealed the location of two residues that when mutated were previously shown to either abrogate (G222D) or restore (G222D/P227L) function of gpVFL. In addition to being inactive, I demonstrated that the G222D mutation also exerts a temperature dependent dominant negative phenotype. My preliminary NMR data suggests that G222D causes gpVC to partially unfold and that this destabilized form of the domain interacts with gpVN in a region that is likely involved in both oligomerization and hexamer-hexamer interactions. To further our understanding of how these mutations exert their effect, I determined the NMR solution structure of gpVC-P227L. My structure reveals that the β7-β8 region of gpVC-P227L is altered compared to gpVC-WT and suggests that the conformational changes in gpVC-P227L may protect the domain from protein-folding defects induced by the G222D mutation.

Optical properties of hybrid structures based on zinc oxide nanocrystals (NCs) and Gallium Nitride quantum well (QW) has been studied. The ZnO NCs thin films on the top of GaN QW structures were fabricated using spin coating. The surface morphology was characterized by scanning electron microscopy (SEM). We have performed temperature dependence time-resolved photoluminescence (TRPL) measurements of the bare AlGaN/GaN QW structures and hybrids, containing ZnO NCs. It was found that at some temperatures the QW PL decay has shorter decay time in the presence of ZnO NCs thin film compared to the bare QW. The effect was stronger for the samples with thinner cap layers. The results are discussed in terms of three models such as exciton nonradiative energy transfer (NRET), tunneling effect, and piezoelectric field influence on the QW exciton energy.

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No description available.