Rapid deposition of YBCO films by laser CVD and effect of lattice mismatch on their epitaxial growth and critical temperature

a-Axis- and c-axis-oriented YBa₂Cu₃O_7–δ (YBCO) films were grown on (100) SrTiO₃ substrate by laser chemical vapour deposition (laser CVD). The effect of lattice mismatch between films and substrates on in-plane and out-of-plane crystallinity and critical temperature (T_C) was investigated. The preferred orientation changed from a-axis to c-axis as the deposition temperature increased from 928 to 1049 K. The c-axis-oriented YBCO showed a minimum of full width at half maximum of 0.5° for the ω-scan and 1.0° for the φ-scan. A smaller mismatch between YBCO films and substrates led a higher crystallinity for in-plane and out-of-plane epitaxial growths. A high T_C of 90 K was obtained for the c-axis-oriented YBCO films. The deposition rate of the YBCO films was 58–101 μm h⁻¹, approximately 60–1000 times higher than that of conventional CVD.     

9‐Oxo‐10(E),12(Z),15(Z)‐Octadecatrienoic Acid Activates Peroxisome Proliferator‐Activated Receptor α in Hepatocytes

The peroxisome proliferator‐activated receptor (PPAR)α is mainly expressed in the liver and plays an important role in the regulation of lipid metabolism. It has been reported that PPARα activation enhances fatty acid oxidation and reduces fat storage. Therefore, PPARα agonists are used to treat dyslipidemia. In the present study, we found that 9‐oxo‐10(E),12(Z),15(Z)‐octadecatrienoic acid (9‐oxo‐OTA), which is a α‐linolenic acid (ALA) derivative, is present in tomato (Solanum lycopersicum) extract. We showed that 9‐oxo‐OTA activated PPARα and induced the mRNA expression of PPARα target genes in murine primary hepatocytes. These effects promoted fatty acid uptake and the secretion of β‐hydroxybutyrate, which is one of the endogenous ketone bodies. We also demonstrated that these effects of 9‐oxo‐OTA were not observed in PPARα‐knockout (KO) primary hepatocytes. To our knowledge, this is the first study to report that 9‐oxo‐OTA promotes fatty acid metabolism via PPARα activation and discuss its potential as a valuable food‐derived compound for use in the management of dyslipidemia.     

Effect of Pressure on Microstructure of <111>‐Oriented β‐SiC Films: Research via Electron Backscatter Diffraction

Scanning electron microscopy (SEM) and high‐resolution electron backscatter diffraction (EBSD) has been employed to study the microstructure development of <111 > ‐oriented β‐SiC films prepared by laser chemical vapor deposition (LCVD) with various total pressure (P_tot). The Surface morphology of films evolved from pyramids with sixfold symmetry to needlelike structure by increasing the P_tot. The EBSD results indicated that the higher P_tot (800 Pa) led to the lower neighbor‐pair misorientation and large in‐plane domains in β‐SiC films.     

Structural study of β‐SiC(001) films on Si(001) by laser chemical vapor deposition

β‐SiC thin films have been epitaxially grown on Si(001) substrates by laser chemical vapor deposition. The epitaxial relationship was β‐SiC(001){111}//Si(001){111}, and multiple twins {111} planes were identified. The maximum deposition rate was 23.6 μm/h, which is 5‐200 times higher than that of conventional chemical vapor deposition methods. The density of twins increased with increasing β‐SiC thickness. The cross section of the films exhibited a columnar structure, containing twins at {111} planes that were tilted 15.8° to the surface of substrate. The growth mechanism of the films was discussed.     

Electrochemical preparation of an electroactive polymer poly(dodecyloxy dibenzothiophene) (polyDDBTh) from hydroxyl dibenzothiophene (HDBTh) as a bioconverted monomer

A combination of biotechnological and electrochemical techniques is employed to synthesize an electroactive π-conjugated polymer. The monomer precursor bearing a hydroxyl group is obtained by the bioconversion of dibenzothiophene. An alkyl chain substituent is introduced by Williamson etherification with the aid of crown ether, and electrochemical polymerization is carried out by repeated potential scanning of the monomer in an electrolytic reaction solution. The polymer film thus prepared is shown to exhibit good electroactive characteristics.     

Nitrogen budgets and environmental capacity in farm systems in a large-scale karst region, southern China

Field surplus nitrogen (N) and farm disposal N are major sources of water pollution in farming systems. These sources are estimated from N budgets in field and whole farms, which are associated with the production and consumption of food. This study was conducted to evaluate these two pollution sources in the steep mountainous karst region of Quibainong, Guangxi Province, southern China. The region is, characterized as an area of upland farms, due to the shallow soils and rapid water drainage through cracks in the limestone. Although field surplus N in 1960 was only 4.1 kg N ha^–1, current field surplus N ranged from 10.1 to 463 kg N ha^–1, with values above 50 kg N ha^–1 in farms along roads and less than 40 kg N ha^–1 in the farms away from roads. The results obtained in near-road farms were similar to those in a previous study of N budgets in China. There was a significant positive correlation between the field surplus N and N application rate, including when the previous data were incorporated. The proportion of manure to total N application decreased with increase of N application. Chemical fertilizer was applied in greater quantity in economically rich farms. Therefore, the increase of field surplus N in Quibainong may be caused by economic improvement. Although livestock and human excreta were stocked in manure barns, unused excreta N increased with the increase of N excreted. The unused excreta N also increased with the decrease of feed self-sufficiency, but was not related to N application rate. These facts indicate that livestock husbandry in Quibainong is related to economic status of farms, but independently of crop production.The N application rate of more than 160 kg N ha^–1 increased field surplus N to an extent greater than crop uptake N, and a N application rate of more than 185 kg N ha^–1 increased the potential nitrate-N concentration to more than 10 mg L^–1. Therefore, 160–185 kg N ha^–1 is suggested to be the environmental capacity to sustain optimal N cycling in Quibainong. The average value of excreta N produced on near-road farms in Quibainong was 171 kg N ha^–1. If excreta N was used evenly for crop cultivation without chemical fertilizer in whole fields, the optimal N cycling would be maintained.The survey conducted here using a questionnaire was effective in evaluating all kind of N flows in the farming systems.     

Decaborane (B10H14) ion implantationtechnology for sub-0.1-μm PMOSFET's

A low-energy, high-dosage boron ion implantation technology using a decaborane (B₁₀H₁₄) molecule is developed. Since B₁₀N₁₄ consists of ten boron atoms, they are implanted with about a one-tenth lower effective acceleration energy and ten times higher effective beam current compared with those of boron. We demonstrated an ultrashallow boron profile with 0.5 keV effective acceleration energy, which does not cause transient enhanced diffusion (TED) after rapid thermal annealing (RTA). Using this technology, we succeeded in fabricating 0.1-μm PMOSFET's with good device performances and excellent suppression of short-channel effects     

TPD study and carbazole hydrodenitrogenation activity of nitrided molybdena–alumina

The relationship between the activity and surface molybdenum species of nitrided 12.5% MoO₃/Al₂O₃ was studied in the hydrodenitrogenation (HDN) of carbazole at 573 K and 10.1 MPa total pressure. The surface molybdenum species were determined by the desorption of nitrogen gas during TPD. The surface area of NH₃-cooled Mo/Al₂O₃ nitrided at 773 and 1173 K was decreased by 8% and 61% from 245 m² g⁻¹ of the fresh MoO₃/Al₂O₃, respectively. The NH₃-cooled Mo/Al₂O₃ catalysts had slightly higher surface area than the He-cooled catalysts. The HDN rate increased with increasing nitriding temperature in the HDN of carbazole on the nitride catalysts. The NH₃-cooled Mo/Al₂O₃ catalysts nitrided at 1173 K were the most active in carbazole HDN and the He-cooled catalyst nitrided at 773 K was the least.     

Liquid—liquid equilibria of ternary ETBE-ETOH-H2O and quaternary ETBE-ETOH-H2O-TBA mixtures

Liquid-liquid equilibria of ETBE-EtOH-H₂O mixtures are measured at 15,25 and 35°C. UNIQUAC and NRTL equations are fitted to the experimental data using ASPEN PLUS. Both the experimental and correlated values of the equilibrium compositions are compared with the values predicted by UNIFAC method. The same procedure is extended to quaternary ETBE-EtOH-H₂O-TBA system at low TBA concentration.