Transition from Ferromagnetism to Antiferromagnetism in Ga1−x_{1-x}Mnx_xN

Using density functional theory, we study the magnetic stability of the Ga$_{1-x}$Mn$_x$N alloy system. We show that unlike Ga$_{1-x}$Mn$_x$As, which shows only ferromagnetic (FM) phase, Ga$_{1-x}$Mn$_x$N can be stable in either FM or antiferromagnetic phases depending on the alloy concentration. The magnetic order can also be altered by applying pressure or with charge compensation. A unified model is used to explain these behaviors.Comment: 4 pages, 4 figure

Characterisation of titanium tetrachloride and titanium sulfate flocculation in wastewater treatment

Flocculation with titanium tetrachloride (TiCl4) and titanium sulfate (Ti(SO4)2) was investigated in terms of different coagulant doses, pH, turbidity, dissolved organic carbon (DOC), UV-254, colour, zeta potential, particle size and molecular weight distribution. The two coagulants were compared with the commonly used coagulants such as ferric chloride (FeCl3) and aluminium sulfate (Al2(SO 4)3). Titanium tetrachloride showed the highest turbidity removal, while titanium sulfate showed the highest reduction of UV-254 and colour at all pH values. The four coagulants were found to have similar organic removal up to 60-67% and resulted in similar organic removal in terms of various MW ranges. The decantability of the settled flocs was very high for titanium tetrachloride, titanium sulfate and ferric chloride compared with aluminium sulfate. The dominating coagulation mechanisms for titanium tetrachloride and titanium sulfate are still to be studied, since different precipitation reactions might take place at different pH even without flocculant addition. Titanium tetrachloride and titanium sulfate were found as effective new coagulants in wastewater treatment not only in terms of organic matter removal, but also in sludge reduction through the production of titanium dioxide. © IWA Publishing 2009

Enhancement of magnetic properties by nitrogen implantation to Mn-implanted p-type GaN

N and Mn ions were co-implanted into p-type GaN and subsequently annealed at 700-900degreesC. Compared with Mn-implanted sample, the (Mn+N)-implanted sample revealed a larger ferromagnetic signal. This was attributed to the increase of Ga-Mn magnetic phases. Mn-N compounds, such as Mn6N2.58 and Mn3N2, decreased and the resistivity significantly increased, meaning a reduction of N vacancies. It is suggested that enhancement in ferromagnetic properties in the (Mn+N)-implanted GaN originated from the reduction of N vacancies and the increase of Ga-Mn magnetic phases.open293

Fabrication of (Ga,Mn)N nanowires with room temperature ferromagnetism using nitrogen plasma

Ferromagnetic properties of (Ga,Mn)N nanowires were examined by treating with nitrogen plasma at 200 ??C. Nanowires grown by chemical vapor deposition were n-type and no secondary phases were found. The magnetic moment increased and was maintained at room temperature by this treatment. Synchrotron radiation photoemission spectroscopy revealed that Ga vacancies significantly increased, but N vacancies decreased by plasma treatment, leading to a decrease of MnGa-VN complex and the enhancement of Mn activation.open111

Microstructural, optical, and magnetic properties of Mn-implanted p-type GaN

The microstructural, optical and magnetic properties of Mn-implanted p-type GaN were investigated. Dilute magnetic semiconductor was achieved by implanting Mn ions into p-type GaN and subsequently annealing. The Ga-Mn magnetic phases contributing to the ferromagnetic property were produced after annealing Mn-implanted p-type GaN below 800??C.open151

Possible Verification of Tilted Anisotropic Dirac Cone in \alpha-(BEDT-TTF)_2 I_3 Using Interlayer Magnetoresistance

It is proposed that the presence of a tilted and anisotropic Dirac cone can be verified using the interlayer magnetoresistance in the layered Dirac fermion system, which is realized in quasi-two-dimensional organic compound \alpha-(BEDT-TTF)_2 I_3. Theoretical formula is derived using the analytic Landau level wave functions and assuming local tunneling of electrons. It is shown that the resistivity takes the maximum in the direction of the tilt if anisotropy of the Fermi velocity of the Dirac cone is small. The procedure is described to determine the parameters of the tilt and anisotropy.Comment: 4 pages, 4 figures, corrected Fig.

Electric Conductivity of the Zero-gap Semiconducting State in Alpha-(BEDT-TTF)2I3 Salt

The electric conductivity which reveals the zero gap semiconducting (ZGS) state has been investigated as the function of temperature $T$ and life time $\tau$ in order to understand the ZGS state in quarter-filled $\alpha$-(BEDT-TTF)$_2$I$_3$ salt with four sites in the unit cell. By treating $\tau$ as a parameter and making use of the one-loop approximation, it is found that the conductivity is proportional to $T$ and $\tau$ for $k_B\gg\hbar/\tau$ and independent of $T$ and $\tau$ for $k_B T\ll\hbar/\tau$. Further the conductivity being independent of $T$ in the ZGS state is examined in terms of Born approximation for the impurity cattering.Comment: 5 pages, 4 figures, submitted to J. Phys. Soc. Jp

Preparation and characterisation of titanium dioxide produced from Ti-salt flocculated sludge in water treatment

During the past few years, titanium salts were investigated as alternative coagulants for the removal of organic matter of different molecular sizes in contaminated water. The flocculation efficiency of Ti-salt was comparable to those of FeCl3 and Al2(SO4)3 salts, commonly used coagulants. Incinerated sludge-TiO2 showed higher surface area and photocatalytic activity than commercially available TiO2. Metal-doped forms were produced by adding coagulant aids such as iron (Fe-), aluminium (Al-) and (Ca-) calcium salts during Ti-salt flocculation to increase pH. Ca- and Al- doped TiO2 showed very high photocatalytic activity compared to Fe-doped TiO2. When tested in a pilot scale plant for treatment of dye wastewater to check practical feasibility of the novel process, the removal ratio of the chemical oxygen demand was comparable to those of commonly used coagulants but the settling of sludge was faster. The TiO2 generated after sludge incineration showed a high photocatalytic activity for degradation of volatile organic compounds and increased the rate of hydrogen production by water photosplitting. TiCl4 coagulant and TiO2 produced from different water sources with different concentrations had low acute toxicity compared to heavy metals and commercial TiO2 when examined based on D. Magna mortality. This paper presents the production, characterisation and the photoactivity of TiO2 produced from Ti-salt flocculated sludge. Different case studies are discussed to highlighted recent advances in this field

Safety and efficacy of an intra-oral electrostimulator for the relief of dry mouth in patients with chronic graft versus host disease: case Series

Objectives: Patients with chronic graft-versus-host disease (cGVHD) often suffer from dry mouth and oral mu - cosal lesions. The primary objective of this study was to investigate the safety of an intra-oral electrostimulator (GenNarino) in symptomatic cGVHD patients. The secondary objective was to study the impact on the salivary gland involvement of cGVHD patients. Study Design: This paper presents a case series. The study included patients treated for 4 weeks, randomly as - signed to the active device and then crossed-over to a sham-device or vice versa. The patients and clinicians were blind to the treatment delivered. Data regarding oral mucosal and salivary gland involvement were collected. Results: Six patients were included in this series. Most of the intraoral areas with manifestations of cGVHD were not in contact with the GenNarino device. Two patients developed mild mucosal lesions in areas in contact with the GenNarino during the study. However, only one of them had a change in the National Institutes of Health (NIH) score for oral cGVHD. The unstimulated and stimulated salivary flow rate increased in 4 out of the 5 pa - tients included in this analysis. Symptoms of dry mouth and general oral comfort improved. Conclusion: This study suggests that GenNarino is safe in cGVHD patients with respect to oral tissues. Furthermore the use of GenNarino resulted in subjective and objective improvements in dry mouth symptoms. A large scale study is needed to confirm the impact and safety of GenNarino on systemic cGVHD

Visible light responsive titanium dioxide (TiO<inf>2</inf>)

Titanium dioxide (TiO2) is one of the most researched semiconductor oxides that has revolutionised technologies in the field of environmental purification and energy generation. It has found extensive applications in heterogenous photocatalysis for removing organic pollutants from air and water and also in hydrogen production from photocatalytic water-splitting. Its use is popular because of its low cost, low toxicity, high chemical and thermal stability, But one of the critical limitations of TiO 2 as photocatalyst is its poor response to visible light. Several attempts have been made to modify the surface and electronic structures of TiO2 to enhance its activity in the visible light region such as noble metal deposition, metal ion loading, cationic and anionic doping and sensitisation, Most of the results improved photocatalytic performance under visible light irradiation. This paper attempts to review and update some of the information on the TiO2 photocatalytic technology and its accomplishment towards visible light region