Core Level Spectroscopy Studies Of Organosilicon Compounds

Si core level X-ray Absorption Fine Structures (XAFS) spectroscopy has been used to study, in the gas phase, the structure and bonding of a series of highly symmetric organosilicon compounds, Si(CH{dollar}\sb3)\sb4{dollar} (TMS), Si{dollar}\rm\sb2(CH\sb3)\sb6{dollar} (HMDS), Ge (Si(CH{dollar}\sb3)\sb3\rbrack\sb4{dollar} (GESI4), Si (Ge(CH{dollar}\sb3)\sb3\rbrack\sb4{dollar} (SIGE4), and Si (Si(CH{dollar}\sb3)\sb3\rbrack\sb4{dollar} (SISI4), which can be used as model compounds for silicon-germanium electronic materials.;The Si K- and L{dollar}\sb{lcub}2,3{rcub}{dollar}-edge X-ray absorption near edge structure (XANES) of HMDS, GESI4 SIGE4 and SISI4 have been recorded with synchrotron radiation and calculated by the multiple-scattering (MS) X{dollar}\alpha{dollar} method. It is found that there is a significant difference in the absorption coefficient in the near-edge region between local Si-Si interactions in these compounds and long range Si-Si interactions in crystalline solids. Both the experiment and the calculation show that, (a) Si-Si and Si-Ge are quite similar in shaping the pre-edge XANES for the three compounds, SIGE4, GESI4 and SISI4, which have identical molecular symmetry; (b) the XANES are different for HMDS and GESI4, where the local bonding is similar; the same is observed for SIGE4 and Si (100) crystal. Therefore, XANES is very sensitive not only to the local structure (nearest neighbours interaction) of the absorbing atom, but also to the extended structure (long range interaction). Based on the calculation results and the comparison of the gas phase and solid state L{dollar}\sb{lcub}2,3{rcub}{dollar}-edge spectra of HMDS, the low-lying energy features are assigned to transitions to mostly valence orbitals.;The extended X-ray Absorption Fine Structures (EXAFS) for TMS, HMDS, GESI4, SIGE4 and SISI4 compounds have also been recorded in the gas phase and analyzed by curve-fitting method. The Si-Ge bond lengths in SIGE4 and GESI4 are found to be 2.38(3) A and 2.396(15) A respectively. The comparison of the Si-Si and Si-Se interatomic distances in crystalline solids has been made.;Valence band photoelectron spectra have been assigned with the aid of MS-X{dollar}\alpha{dollar} calculation and the photon dependence of the intensities for TMS, HMDS, SISI4, GESI4 and a cyclic compound (Si(CH{dollar}\sb3)\sb2\rbrack\sb6{dollar} (DCHS). The correlation between the binding energy of the highest occupied molecular orbital measured by photoelectron spectroscopy and the inflection energy in K- and L{dollar}\sb{lcub}2,3{rcub}{dollar}-edge XANES is discussed

John Rawls: theory of justice and Communitarianism criticisms

The purpose of this paper is to analyze the John Rawls's theory of justice as fairness developed in A Theory of Justice and Political Liberalism, focusing on its model of complementarity between the deontological and the teleological with procedural and substantive, seeking to answer some of criticisms raised by the authors, communitarian and Rawlsian theory of justice for trying to point out their similarities. Natural of the criticisms of the communitarian theory of justice as fairness, analyze the aspects limited in the model teleological ethics, focus the fundamental relationship between the procedural and substantive, and finally present the answers to communitarian criticisms of Rawls, emphasizing the specificity of his conception of justice

Triplet–Triplet Energy Transfer Study in Hydrogen Bonding Systems

The 2,6-diiodoBodipy–styrylBodipy hydrogen bonding system was prepared to study the effect of hydrogen bonding on the triplet–triplet-energy-transfer (TTET) process. 2,6-DiiodoBodipy linked with N-acetyl-2,6-diaminopyridine (D-2) was used as the triplet energy donor, and the styrylBodipy connected with thymine (A-1) was used as triplet energy acceptor, thus the TTET process was established upon photoexcitation. The photophysical processes of the hydrogen bonding system were studied with steady-state UV-vis absorption spectroscopy, fluorescence spectroscopy, fluorescence lifetime measurement and nanosecond time-resolved transient absorption spectroscopies. The TTET of the intramolecular/hydrogen bonding/intermolecular systems were compared through nanosecond transient absorption spectroscopy. The TTET process of the hydrogen bonding system is faster and more efficient (kTTET = 6.9 × 104 s–1, ?TTET = 94.0%) than intermolecular triplet energy transfer (kTTET = 6.0 × 104 s–1, ?TTET = 90.9%), but slower and less efficient than intramolecular triplet energy transfer (kTTET > 108 s–1). These results are valuable for designing self-assembly triplet photosensitizers and for the study of the TTET process of hydrogen bonding systems

Determination method of the structure size interval of dynamic similar models for predicting vibration characteristics of the isotropic sandwich plates

A method is studied for determining the structure size interval of dynamic similar models of the isotropic sandwich plates. Firstly, a comparison between the two theories of plates, the Resineer theory and the Hoff theory, is conducted, including their governing equations and the ANSYS analytic solutions of frequency. The Resineer theory is chosen as the basic theory of this paper finally. Secondly, the scaling laws between the model and prototype of isotropic sandwich plate are established by combining the dimensional analysis and governing analysis. Both complete and incomplete geometric similarity conditions are discussed. Thirdly, the determination method of the structure size interval of the models is proposed. The nature vibration mode keeps the same and the nature frequency and harmonic response keep in proportion with the prototype of the sandwich plate. At last, the flow step of the intervals determination method is given

Examination of the Religious Nature of Secular Nationalism

This study aims to explore whether secular nationalism can be considered as a type of religion. In the first section, the term “religious nationalism” is perceived as nationalism that generally demonstrates characteristics commonly associated with religion. In the second section, definitions of nationalism and religion are explained respectively. This study then draws parallels between the two, depicting religion as a good “metaphor” for nationalism, thereby describing basic concepts of religious nationalism with reference to some policies in Revolutionary France in 1790 as an instance. In section three, more specific overlapping characteristics possessed by both nationalism and religion are elaborated in which this study not only analyses similarities between the hierarchical structure of the government and the Church, but also compares the devotion of the “state” maintained by citizens to worship of “God” maintained by believers. Drawing inspiration by a variety of scholars ranging from Carlton Hayes to Friedrich Nietzsche, this study eventually reaches a conclusion that, despite variations in the intensity of national sentiments across different countries, secular nationalism is undoubtedly a type of religion supported by these similar characteristics described above

Influence of uron resins on the performance of uf resins as adhesives for plywood

Uron resin, a kind of urea-formaldehyde (UF) resin containing much more uron structure, were prepared. Several modifi ed UF resins were obtained from mixing uron resins with normal UF resins as well as synthesizing UF resin with uron resin as raw material. This work demonstrated that the introducing of the uron structure reduced free formaldehyde content of UF resin and formaldehyde emission levels in bonded plywood panels signifi cantly, the former were reduced by 76% and 84% in the latter. The synthesis time of uron resin can be shortened to 8 hours. The test result of free formaldehyde content, formaldehyde emission levels and bond strength indicated that specimen of 20 parts uron resin synthesized in 8 hours mixed with 100 parts UF resins (F/U molar ratio of 1.3) had a potential advantage to industrial application. The benefi cial effect of uron resin on the performance of UF resin can be attributed to the opening of uron cycle structure and the following reaction with free formaldehyde and its oligomeric glycol forms

Direct correlation of electrochemical behaviors with anti-thrombogenicity of semiconducting titanium oxide films

Biomaterials-associated thrombosis is dependent critically upon electrochemical response of fibrinogen on material surface. The relationship between the response and anti-thrombogenicity of biomaterials is not well-established. Titanium oxide appears to have good anti-thrombogenicity and little is known about its underlying essential chemistry. We correlate their anti-thrombogenicity directly to electrochemical behaviors in fibrinogen containing buffer solution. High degree of inherent n-type doping was noted to contribute the impedance preventing charge transfer from fibrinogen into film (namely its activation) and consequently reduced degree of anti-thrombogenicity. The impedance was the result of high donor carrier density as well as negative flat band potential