New Bi-metallic Single Source Precursors for the Deposition of Thin Films of Semiconductor Ceramics

Stable binary single source precursors （SSP） for the deposition of thin films of ceramic semiconductors of composition SnO·GeO were synthesized by close circuit chemical vapour deposition （CCCVD） method. Elemental analysis and spectroscopic techniques were used to characterize the precursors. Scanning electron microscopy （SEM） and energy dispersive spectroscopy （EDS） were employed to characterize the thin films. Resistivity measurements were conducted to show that the films are of semiconducting nature.

ZnO/TiO2 Nanocomposite Synthesized by Sol Gel from Highly Soluble Single Source Molecular Precursor

Single source molecular precursors （SSPs） provide an opportunity to get control over the microstructure of nanomaterials at atomic level. A SSP was designed and developed for the synthesis of ZnO/TiO2 nanocomposite by sol gel method. In a typical synthe-sis process, a bimetallic molecular compound with chemical formula [Cl2TiZn（dmae）4] （dmae=dimethylaminoethanol） was synthesized and its chemical composition was deter-mined by elemental analysis. The obtained compound has shown excellent solubility in common organic solvents, a prerequisite for its use in sol gel method as SSP. The SSP ob-tained was controllably hydrolyzed by adding equimolar amount of water using ethanol as solvent to get ZnO/TiO2 nanocomposite gel. The resulting gel was precipitated at pH=9 and sintered at 200 ℃ （T200）, 400℃ （T400）, and 600℃ （T600）. The XRD analyses have shown that the as synthesized （non-sintered, T00） powder was amorphous. However, the crystallinity improved upon sintering, and the XRD analyses revealed that the resulting nanomaterials were composed of mixed oxides i.e., ZnO and TiO2. The ZnO was in wurtzite （hexagonal） while the TiO2 was in brookite （orthorhombic） phase. The increase in particlesize was further confirmed from BET analysis and SEM micrographs. The IR spectra ob-tained for the resulting powder have shown the peculiar vibrational bands for Zn-O and Ti-O. Furthermore, the IR spectra revealed that the non-sintered ZnO/TiO2 nanocomposite had significant number of OH group which was removed upon sintering. The photocatalytic activities of the ZnO/TiO2 nanocomposites were tested. All the samples have shown good photocatalytic activities. However, the T400 has shown higher activity than the T00, T200, and T600. The higher photocatalytic activity of T400 than T00, T200, and T600 may be due to improved crystallinity which ensures efficient grain boundary interfaces.

Research on Locating the Source of Abnormal Disturbances in the Border Region of Shaanxi and Gansu

Abnormal disturbances, s uch as sharp pulses, w ere observed by vertical pendulum tiltmeters in Wudu, Hanzhong and Ningshaan seismic stations on August 6, 2008.According to the time and spatial location of the anomalies,we build a"source precursor"propagator to calculate possible focal region by aid of quasi-Newton least squares and grid search methods. The calculated focal region is located at the aftershock area of the Wenchuan earthquake on the northern section of Longmenshan fault zone,which may be related to the 54km-away M S5. 0 Pingwu-Beichuan earthquake,with starting time of about thirty three hours before the earthquake.

The Application of KMnO_4 Pre-oxidation in Emergency Treatment of High-algae Source Water

Mobile emergency pilot water plant was used to carry out pilot study of KMnO4 pre-oxidation enhanced coagulation treating high-algae source water. Research showed that the optimal dosages of coagulant and KMnO4 in the process were 6 and 0. 4- 0. 6 mg / L respectively. Under the dosage,removal rate of water turbidity after precipitation rose by 11% than simple coagulation,and removal rate of algae rose by 15%. Removal rates of total amount of odor and GSM by the process were respectively 73% and 59%. The removal rate of total amount of algae by KMnO4 preoxidation was 40%,and removal effect of THM precursors was obvious.

Numerical simulation of spatial-temporal evolution characteristics of subsurface fluid based on strong body seismogenic model$$$$

Using finite element technique of the plane-strain problem in solid-liquid two-phase medium, we Studied the char acteristics of 'field precursors' and 'focus precursors' of subsurface fluid and their spatial-temporal evolution in case of dip-slip earthquake. The results show that: ① the change of ground fluid is slow and the anomaly is not prominent in the early period which is of elastic accumulation and non-linear; ② dilatancy emerges and anomalyfocus mainly in the source region in the moderate period which is hardening and of local dilatancy. In the period the focus precursors emerge earlier than the field precursors; ③ anomalies spreed continuously in the source area and new regions with big anomaly emerge out of the source region in the middle-short period which is of large scale dilatancy.

Synthesis, Crystal Structure and Pyrolysis of a Heterobimetallic Peroxo-titanium(IV) Nitrilotriacetate Complex

A new heterobimetallic nitrilotriacetatoperoxotitanate complex with the formula of [Mn（H2O）5]2[Ti（O2）2O（nta）2]·7H2O （1, C6H6O6N = H3nta） has been isolated in pure crystals. It was characterized by elemental analyses, IR, thermal analysis （TGA） and single-crystal X-ray diffraction. Complex 1 crystallizes in monoclinic, space group C2/c with a = 15.088（3）, b = 13.311（3）, c = 17.741（4） , β = 100.92（3）°, Z = 4, V = 3498.6（12） 3, Mr = 968.19, Dc = 1.838 g/cm3, μ = 1.266 mm-1, F（000） = 1992, R = 0.0337 and wR = 0.0819. Single-crystal X-ray analysis reveals that the titanium atom is N,O,O＇,O＇＇-chelated by the nitrilotriacetate and O,O＇-chelated by the peroxo group, and is coordinated to the bridging O atom in an overall pentagonal-bipyramidal geometry. The manganese ions in the compound are both 6-coordinated by five water molecules and one bridged carboxylato oxygen atom. A decameric water cluster consisting of a cyclic water hexamer in a boat fashion is also found in complex 1. The TGA and XRD results prove that 1 undergoes facile thermal decomposition to form the mixture of Mn2O3 and TiO2 at 600～800 ℃, and pure MnTiO3 at 900 ℃.

Preparation of γ-Gd_2 S_3 via thermolysis of Gd[S_2 CN(C_4 H_8)]_3 ·phen coordination

Pure γ-Gd2S3 was synthesized by the thermolysis of a single Gd[S2CN（C4H8）]3 phen complex precursor in a flow of argon carrier gas containing sulfur vapor. The complex precursor was decomposed into amorphous Gd2S3 and carbon at about 350 ℃. Crystalline y-Gd2S3 could be achieved at temperature exceeding 600 ℃, and the obtained γ-Gd2S3 presented a very high degree of crystallinity at 800 ℃. Carbon prevented the formation of Gd2O2S impurity in the preparation of y-Gd2S3. However, the carbon blackened the product. At temperature ≥ 1000 ℃, the residual carbon impurity could be efficiently removed by introducing sulfur into the system for the volatile CS2 could be formed in situ via the reaction of sulfur with the deposited carbon. In the meantime, S also promoted the crystallization of γ-Gd2S3 remarkablely.