Our goal was to assess regional differences in denticle density and skin tensile properties in four coastal species of shark. We hypothesized that the denticle density, tensile strength (MPa), stiffness (MPa), and toughness of skin (MJ·m^-3) would vary regionally along the body of an individual and among species. An hourglass-shaped punch was used to extract the skin samples at 10 anatomical landmarks and denticle density was quantified. Denticle density varied significantly among both regions and species, and showed a significant species by region interaction. Skin samples were tested in tension at a strain rate of 2 mm-s until failure. We found significant species and region effects for all tensile and denticle density properties. Also, denticle density increases with skin stiffness but decreases with toughness. Shark skin toughness is similar to that of mammalian tendons. These data show shark skin functions as an exotendon, able to conserve energy during swimming. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Zhang, Zhongxiang. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Ge(100) has atomic and electronic structures quite similar to those of Si(100). As a comparison, we have studied the oxidation of Ge(100) surface. Our comparison of the initial oxidation of Ge(100) with that of Si(100) by molecular oxygen shows that the precursor-mediate mechanism and direct adsorption mechanism are common to both systems. (Abstract shortened by UMI.) / It is often been argued that a direct [2+2] addition of unsaturated hydrocarbons to the Si-Si dimer is symmetry forbidden, according to the Woodward-Hoffmann rule. This view is now challenged by our calculations on the reaction path for a concerted [2+2] addition of C2H4 to a Si-Si dimer on Si(100), which identifies a barrier of only ∼0.1eV. Our analysis shows that this is due to the peculiar feature for a surface reaction, when the HOMO and LUMO bands cross the Fermi level of the substrate, as previously suggested by Hoffmann. It illustrates an important conceptual distinction between a gas phase and a surface reaction. / Many previous theoretical studies on the interaction between O2 and Si(100) have neglected the differences between triplet O2 (ground state) and singlet O2 (excited state), and are thus unable to explain the know experimental observations in surface scattering of O2. We demonstrate that in reality, triplet O2 can also react with Si(100). With our computation results on the potential energy curves of the adsorption of triplet O2 on Si(100) and the adsorption structures along these curves, we can explain the known experimental results. The proper adsorption pathway goes through a shallow physisorption potential well, a small transition state and reaches a molecular adsorption state. There are also some interesting interactions between the potential energy curves of the triplet O2 adsorption and singlet O2 adsorption. / This thesis addresses the basic physics and chemistry of some surface reactions by first-principles methods based on density functional theory. The reaction systems probed by this thesis include the cycloaddition of C2H4 on Si(100), and initial oxidation of Si(100), Ge(100) and Al(111) by molecular oxygen. They are all technologically important systems and yet simple enough for us to study them in details theoretically. Although they have been studied both experimentally and theoretically, our first principles calculations reveal new insights that are contrary to prevalent opinions. / Fan Xiaoli = 从头算法研究研究在硅100, 锗100 和铝111 表面上的反应 / 范晓丽. / "June 2005." / Adviser: Lau Woon-ming Leo. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 3854. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Text in English; abstracts in English and Chinese. / School code: 1307. / Fan Xiaoli = Cong tou suan fa yan jiu yan jiu zai gui 100, zhe 100 he lü111 biao mian shang de fan ying / Fan Xiaoli.

Finally, we have systematically investigated the SAMs of four specially designed anthracene-based thiols. These molecules include 9-mercaptoanthracene (MA), (4-mercaptophenyl) (9-anthryl) acetylene (MPAA), (4-mercaptophenyl) (10-nitro-9-anthryl) acetylene (MPNAA), and (4-mercaptophenyl) (10-carboxyl-9-anthryl) acetylene (MPCAA) adsorbed on Au(111). For all SAMs, the parallel-displaced pi-pi stacking interactions and adsorbate-substrate interactions are dominant, which leads to a common wave-like row structure along the pi-pi interaction direction. Compared to MA, the phenyl-acetylene group of MPAA acts as space, which enhances the molecular flexibility and improves the long-range ordering. The repulsive dipole-dipole interactions of MPCAA cause a slight enlargement of the unit cell. For MPCAA, a structure similar to that of MPNAA is formed first. Then with an extended growth time, hydrogen bonding drives the pairing of adjacent inter-row molecules in the expenses of compromising intea-row parallel-displaced pi-pi interaction. / Fourth, we studied the growth of CF3 CH2SH on Au(111). We found that the adsorbed molecules mainly form low coverage phases even after a long time growth in solution. This is attributed to the strong dipole-dipole repulsion between the molecules. However, due to the special short molecular geometry, the molecules can pack with a denser packing arrangement in comparison to the long-chain fluorinated thiols. A "liquid phase" is present in all the samples studied, which solidifies quickly at elevated temperatures. Annealing causes both the growth of stable phases and desorption of weakly adsorbed molecules. Six different stripe phases with the configuration of p x 3 and p x 2a are observed on the surface. The inter-molecular interactions are either van der Waals in nature or the Columbic attraction between the slightly negatively charged F atoms and the slightly positively charged H atoms of the CH 2 group. / Second, we have observed several dash-line structures on HOPG with STM. We suggest that the structures are formed by the gliding of some top surface layers of carbon atoms. The arrest of the gliding action causes the formation of a ridge of carbon atoms and the relaxation of the ridge at room temperature leads to the formation of amorphous carbon clusters queuing along the ridge. As such, the dash-line structures are formed. They are defect structures of HOPG. / Several adsorption systems have been studied by atomic force microscopy (AFM) and scanning tunneling microscopy (STM) in this thesis. / The first system is Fe deposited on 3 x 3 -Al on Si(111). We found by STM that at a low coverage of less than 0.1ML and room temperature; most Fe atoms are incorporated to the 3 x 3 -Al adatom lattice. When the Fe coverage increases further, clustering of Fe atoms into three-dimensional islands occurs. These clusters draw neighboring silicon surface or sub-surface atoms and the formation of Fe-Si bonds is evident. Samples with Fe deposited at or above 400°C show Fe-Si with the CsCl crystalline structure and a top surface lattice of 2 x 2 Si (111) in nature. The crystalline island has a triangular shape and a preferred location along the step edges of the Si(111) surface. / Third, STM has been used successfully in determining the molecular morphology of some novel dendrimers. The morphology of dispersed individual molecule can be identified. In this study, we found that AFM is not applicable because of considerable tip-molecule interactions which distort the morphology of the probed molecule. / Xi Luan = SPM对表面吸附分子的研究 / 席峦. / "June 2005." / Adviser: Lau Woon Ming Leo. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0491. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 109-117). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Text in English; abstracts in English and Chinese. / School code: 1307. / Xi Luan = SPM dui biao mian xi fu fen zi de yan jiu / Xi Luan.

Gong, Xiangjun = 新型全內反射顯微鏡的搭建及其在膠體研究中的應用 / 龔湘君. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2008. / Includes bibliographical references. / Abstracts in English and Chinese. / Gong, Xiangjun = Xin xing quan nei fan she xian wei jing de da jian ji qi zai jiao ti yan jiu zhong de ying yong / Gong Xiangjun. / Abstract (Chinese) --- p.i / Abstract --- p.iii / Contents --- p.v / Acknowledgement --- p.vii / Chapter Chapter 1 --- Introduction to Total Internal Reflection Microscopy (TIRM) / Chapter 1.1 --- History of TIRM --- p.1 / Chapter 1.2 --- Instrumentation --- p.1 / Chapter 1.2.1 --- Apparatus --- p.1 / Chapter 1.2.2 --- Optical Tweezer --- p.3 / Chapter 1.3 --- The principle of the technique --- p.5 / Chapter 1.3.1 --- Total Internal Reflection --- p.5 / Chapter 1.3.2 --- Details on Scattering of the Evanescent Wave --- p.7 / Chapter 1.3.3 --- Data analysis --- p.14 / Chapter 1.3.4 --- A typical potential energy profile --- p.17 / Chapter 1.4 --- Noise Analysis and Removal Method --- p.19 / Chapter 1.4.1 --- Noise analysis --- p.19 / Chapter 1.4.2 --- Noise removal: low-pass filtering --- p.22 / Chapter 1.5 --- Other techniques on force measurement --- p.25 / Chapter 1.6 --- References --- p.27 / Chapter Chapter 2 --- Experiments on TIRM Calibration / Chapter 2.1 --- Introduction --- p.30 / Chapter 2.2 --- Pre-Experimental Section --- p.30 / Chapter 2.2.1 --- Glass Surface Preparation Methods --- p.30 / Chapter 2.2.2 --- Experimental Setup --- p.33 / Chapter 2.3 --- Calibration Results and Discussion --- p.36 / Chapter 2.4 --- Conclusions --- p.42 / Chapter 2.5 --- References --- p.43 / Chapter Chapter 3 --- TIRM investigation on polymer-induced collodial interactions / Chapter 3.1 --- Introduction to polymer-induced forces --- p.45 / Chapter 3.1.1 --- Non-absorbing case - depletion force --- p.46 / Chapter 3.1.2 --- Attached polymer layers --- p.49 / Chapter 3.2 --- Applications of TIRM in polymer-mediated colloidal interactions --- p.54 / Chapter 3.2.1 --- Measurements on depletion force --- p.54 / Chapter 3.2.2 --- Measurements on Steric Forces --- p.56 / Chapter 3.3 --- Direct measurement of thermosensitive Poly(N-isopropylacrylamide)-mediated colloidal interactions with TIRM --- p.56 / Chapter 3.3.1 --- Introduction --- p.56 / Chapter 3.3.2 --- Experimental Section --- p.57 / Chapter 3.3.3 --- Results and Discussion --- p.60 / Chapter 3.3.4 --- Conclusions --- p.73 / Chapter 3.4 --- References --- p.74 / Publication List --- p.77

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 87-91). Also available on the Internet.

published_or_final_version / abstract / toc / Physics / Master / Master of Philosophy

Theoretical studies on the wetting of cylindrical solid surfaces with axisymmetric rugosities explicitly showed the presence of contact angle hysteresis, non-equilibrium jumps during contact line motion and the formation of composite surfaces. For physically rough surfaces with unidirectional randomness it was shown that hysteresis increases with decreasing roughness dimensions and with increasing standard deviation in the solid surface slope distribution. / The wetting of solid surfaces by liquids was investigated by a new tensiometric technique called capillarography. At large roughness wavelengths ((TURN)100 (mu)m) the contribution of concentric sawtooth-shaped regular roughness was found to be close to the values calculated theoretically. At smaller roughness wavelengths ((TURN)1 (mu)m) the wetting is complicated by intrinsic roughness and chemical heterogeneity. / High energy surfaces such as platinum and quartz exhibit a regular stick-jump behavior when wetted with water above a very low critical contact line velocity. This is caused by minute amounts of surface active impurities in the system. From the experimental data it can be deduced that surface active molecules diffuse onto and over the solid surface. / A relaxation of the contact angle was observed when an initially slow moving contact line was brought to a full stop. This is attributed to the slow establishment of a new equilibrium, possibly by surface capillary waves, involving metastable contact line positions separated by energy barriers. For receding contact angles, the main cause of the relaxation seems to be a stabilization of a liquid film left behind a receding contact line. / The observations made in this study contribute to a better understanding of the complicated nature of the wetting of solids.

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1990. / Includes bibliographical references (leaves 118-122) / Microfiche. / xv, 122 leaves, bound ill. 29 cm

Thesis (PhDBiomedicalScience)--University of South Australia, 2001.