Advanced Materials Research Vol. 918

Abstract: Magnesium tetraphenylporphyrin (MgTPP) had been synthesized with tetraphenylporphyrin (TPP) and magnesium acetate according to reported paper. The photoanode of photoelectrochemical biofuel cell (PEBFC) was constructed including TiO₂ conductive film and photosensitizer Magnesium Tetraphenylporphyrin. The interaction between MgTPP sensitizer and TiO₂ was evaluated by X-ray photoelectron spectra, indicating that the MgTPP adsorbed on TiO₂ was easier to accept electrons compared with synthesized MgTPP itself. The spectroscopic properties of synthesized MgTPP and MgTPP-sensitization TiO₂ in dichloromethane solution were obtained by Uv-vis absorption spectra, demonstrating that the characteristic absorption peaks of MgTPP on TiO₂ displayed slight red shift compared with synthesized MgTPP. The photocurrent action spectrum evidenced that current of the PEBFC originated from MgTPP-sensitization TiO₂ photoanode.

Abstract: Straight rod-shaped mesoporous silica materials (SRMS) were successfully prepared using polyvinylpyrrolidone and triblock copolymer as dual template, which would be further functionalized with (3-aminopropyl) triethoxysilane. SRMS and functionalized SRMS (NH-SRMS) were characterized by means of small-angle X-ray powder diffraction, field emission scanning electron microscopy, transmission electron microscopy, N₂ adsorptiondesorption. The results indicated that SRMS was straight rod-shaped mesoporous silica with a hexagonal symmetry structure (p6mm) and the structure did not change after functionalization. A comparative study of the loading and release of ibuprofen on the carriers of SRMS and NH-SRMS were carried out in phosphate buffered saline. NH-SRMS exhibited a lower release rate than SRMS, suggesting that NH-SRMS was a promising carrier for achieving prolonged drug release.

Abstract: TiO₂ nanorods were successfully fabricated via hydrothermal method using cetyltrimethylammonium bromide (CTAB) as the structure-directing agent. The synthesized samples were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), and field-emission scanning electron microscope (FESEM). The study showed that as-prepared samples were the mixed crystalline phase of rutile and brookite. The weight fraction of rutile and brookite in the mixed-phase were accurately tuned by changing the concentration of CTAB. The morphology of prepared samples was TiO₂ nanorods with the diameter of 2530 nm and the length of 80150 nm. The samples for degradation of papermaking wastewater under ultraviolet light irradiation showed better photocatalytic activity than the commercial Degussa P25. HRT-3 prepared from CTAB: TBT molar ratio of 0.48 exhibited the highest photocatalytic activity, achieving 47.2% COD_cr removal rate and 89.5% chroma removal rate under irradiation 12 h.

Abstract: Mesoporous TiO₂ with high surface area (S_BET) and different pore size was successfully fabricated via hydrothermal method using cetyltrimethylammonium bromide and PEO-PPO-PEO as the structure-directing agents, and tetrabutyl titanate (TBT) as titanium source. S_BET and pore size of the materials were adjusted by using different amount of TBT. S_BET was increased as TBT changing from 0.5 g to 1.0 g, and then dropped as 2.0 g TBT added. Among as-prepared samples (PC), PC-1.0 showed the highest S_BET of 92.72 m² g¹. With the increase amount of TBT, pore size increased from 10.36 nm to 12.72 nm. The phtocatalysis study showed that PC-1.0 had the highest percent degradation of 99.6 %. We believed that the design and synthesis of mesoporous TiO₂ with changing mesopores and S_BET are important for both fundamental and technological viewpoints.

Abstract: In this study, the transport theorem of phonons and electrons is utilized to create a model to predict the thermal conductivity of composite materials. By observing or assuming the dopant displacement in the matrix, a physical model between dopant and matrix can be built, and the composite material can be divided into several regions. In each region, the phonon or electron scattering caused by boundaries, impurities, or U-processes was taken into account to calculate the thermal conductivity. The model is then used to predict the composite thermal conductivity for several composite materials. It shows a pretty good agreement with previous studies in literatures. Based on the model, some discussions about dopant size and volume fraction are also made.

Abstract: N doped TiO₂ was prepared by methods of sol-gel, precipitation, and temperature programmed nitridation (TPN) with NH₃, respectively. The physical structure and chemical properties of the prepared N-TiO₂ were characterized by DRS, XRD, XPS, and EPR spectra techniques. The result of XRD illustrated that all the samples were anatase, and no rutile or brookite phase. XPS and EPR indicated that N-TiO₂ prepared by precipitate exist Ti³⁺ on the surface of TiO₂. DRS pattern demonstrated N doping lead to the band gap narrow of all the samples, and the smallest band-gap energy of the samples prepared by precipitation was about 2.45eV. The photocatalytic activities were investigated by the photocatalytic degradation of methylene blue (MB) under simulated sunlight, and the highest activities reached to 75% during 120min.

Abstract: Discovery of bioactive ingredients from plants and fungi is always the hot spots in medicinal chemistry. The trametenolic acid B was a bioactive lanostane-type triterpenoid in Trametes lactinea (Berk.) Pat. In this work, four semi-synthetic derivatives were synthesized, characterized and evaluated the anti-gastric cancer activities against HGC-27 cells with the aim of obtaining better anti-tumor agents. The compounds 2a and 3b possessed good anti-proliferative effects under normal physiological conditions, and their anti-cancer effects increased as the pH decrease to 5.5 with the IC₅₀ of 17.55 and 10.63 μM, respectively. These compounds might be further developed as anti-gastric cancer drugs.

Abstract: The mechanism of the formation of Cooper pairs and their role in the occurrence of nondissipative diamagnetic currents is investigated. In the previous works [1-, we suggested that in the materials with large HOMO-LUMO gaps (ΔE_HOMO-LUMO,N), the Cooper pairs are formed by the large HOMO-LUMO gaps as a consequence of the quantization of the orbitals by nature, and by the attractive Coulomb interactions between two electrons with opposite momentum and spins occupying the same orbitals via the positively charged nuclei. On the other hand, according to the recent experimental research [, the Cooper pairs have been observed at room temperatures in the neutral benzene (6an), naphthalene (10ac), anthracene (14ac), and coronene molecules. That is, our prediction in our theoretical researches [1-can be well confirmed by the recent experimental research [, and our previous theory can be reasonably applied to the explanation of the mechanism of the occurrence of the granular high temperature superconductivity in carbon materials [. We show that the forming of Cooper pairs [ can be well explained by our theory previously suggested [1-. We also suggest the reasonable mechanism of the occurrence of granular high temperature superconductivity in the graphite powder treated by water or exposed to the hydrogen plasma, discovered by Esquinazi et al. [, on the basis of our previous theoretical works described above [1-, which can be well confirmed by the recent experimental work [. We also suggest the general guiding principle towards high temperature superconductivity. We suggest that any material with large ΔE_HOMO-LUMO,N value (more than a few eV), in which valence bands are completely occupied by electrons, which has been believed to be typical insulator in view of solid state physics and chemistry, has a possibility to exhibit high temperature superconductivity in solids.

Abstract: A kind of hill-like black silicon have been designed and fabricated by using the combination method of KOH anisotropic etching and gold-assisted HF etching. Pillars array on the surface of a silicon sample was obtained by KOH etching with a SiN_x film dots pattern used as a mask. The sample was then etched in the oxidant HF solution catalyzed by Au nanoparticles for 5 minutes. The etched sample appears dark black. This black silicon is orderly hill-like textures in micro-scale with density nanopores on them. It can suppress the reflection to less than 4% in wavelength range from 250nm to 1000nm, and to about 2.5% at the wave number of 2000-4000 cm^-1. It also has high additional absorption in IR range.