Resource allocation and optimization techniques in wireless relay networks

Relay techniques have the potential to enhance capacity and coverage of a wireless network. Due to rapidly increasing number of smart phone subscribers and high demand for data intensive multimedia applications, the useful radio spectrum is becoming a scarce resource. For this reason, two way relay network and cognitive radio technologies are required for better utilization of radio spectrum. Compared to the conventional one way relay network, both the uplink and the downlink can be served simultaneously using a two way relay network. Hence the effective bandwidth efficiency is considered to be one time slot per transmission. Cognitive networks are wireless networks that consist of different types of users, a primary user (PU, the primary license holder of a spectrum band) and secondary users (SU, cognitive radios that opportunistically access the PU spectrum). The secondary users can access the spectrum of the licensed user provided they do not harmfully affect to the primary user. In this thesis, various resource allocation and optimization techniques have been investigated for wireless relay and cognitive radio networks

Mass Production and Photocatalytic Activity of Highly Crystalline Metastable Single-Phase Bi₂₀TiO₃₂ Nanosheets

Highly crystalline metastable bismuth titanate (Bi20TiO32) nanosheets are prepared via a simple green wet chemical route for the first time. The Bi20TiO32 photocatalysts were characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FESEM), energy dispersive spectrum analysis (EDS), X-ray diffraction (XRD), N2 adsorption−desorption (BET), and UV−vis diffuse reflectance spectroscopy (DRS). Inspiringly, Bi20TiO32 nanosheets showed high photocatalytic activity for the degradation of nonbiodegradable azo dye under simulated sunlight and visible-light irradiation. The experimental results showed that the photocatalytic activity of the Bi20TiO32 nanosheets was superior to the commercial Degussa P25 TiO2, and demonstrated that the morphology and crystal structure have a distinct effect on the photocatalytic activity. The reasons for the high photocatalytic activity and the formation mechanism of Bi20TiO32 nanosheets are also discussed

Intercalation of Aggregation-Free and Well-Dispersed Gold Nanoparticles into the Walls of Mesoporous Silica as a Robust “Green” Catalyst for <i>n</i>-Alkane Oxidation

Intercalation of Aggregation-Free and Well-Dispersed Gold Nanoparticles into the Walls of Mesoporous Silica as a Robust “Green” Catalyst for n-Alkane Oxidatio

Application and Properties of Microporous Carbons Activated by ZnCl₂: Adsorption Behavior and Activation Mechanism

Herein, polypyrrole-based porous carbon (PPC) was prepared by ZnCl2 activation for toluene adsorption from paraffin liquid. The structure properties were adjusted by a dosage of activating agents and carbonization temperature. The result with a 3:1 mass ratio of ZnCl2/PPy at 600 °C showed the highest micropore area and percentage of micropore volume of 1105 m2/g and 86.26%, respectively. In addition, the PPC surface was rich in functional groups and obtained a high N-doped content from 7.00 to 8.82%. The toluene adsorption behavior onto the PPC was comprehensively investigated including isotherms, kinetics, and thermodynamics. The adsorption isotherm accorded with the Freundlich model well, and the kinetic model was fitted more closely to the pseudo-second-order chemisorption. The thermodynamic research uncovered that the adsorption was spontaneous and an endothermic process in essence. The ZnCl2 activation mechanism is discussed based on TG/TGA curves and pore structure analysis at last. The devised way of synthesized microporous carbon is green and simple, which is suited to mass production for the adsorption of toluene from paraffin liquid and reducing environmental pollution

Additional file 3 of Clinical significance and oncogenic function of NR1H4 in clear cell renal cell carcinoma

Additional file 3: Figure S1. The relationship between NR1H4 expression and immune cell infiltration levels in ccRCC. (A) The correlations between NR1H4 expression and immune infiltration levels of ccRCC by TISIDB database analysis. (B) The correlations between NR1H4 expression and macrophage infiltration levels by XCELL algorithm analysis

Additional file 2 of Clinical significance and oncogenic function of NR1H4 in clear cell renal cell carcinoma

Additional file 2: Table S2. Univariate and multivariate analyses for Clear Cell Renal Cell Cancer patients on overall survival in the TCGA

Additional file 1 of Clinical significance and oncogenic function of NR1H4 in clear cell renal cell carcinoma

Additional file 1: Table S1. Indicated primers used in PCR experiments

Additional file 4 of Clinical significance and oncogenic function of NR1H4 in clear cell renal cell carcinoma

Additional file 4. Original blots in the manuscript

TiO₂ Nanoflakes Modified with Gold Nanoparticles as Photocatalysts with High Activity and Durability under near UV Irradiation

Titania nanoflakes modified with gold nanoparticles (NPs) were successfully prepared by depositing of Au NPs onto TiO2 nanoflakes using a direct “green” process in the absence of organic capping agents. The photocatalyst has been characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and UV−vis diffuse reflectance spectroscopy. Results of these analyses revealed that the Au NPs (∼1 nm) are homogeneously dispersed on the surface of highly crystalline TiO2 (anatase) nanoflakes with a narrow size distribution. Further, XPS studies indicate a strong electronic interaction between Au (in metallic state) and TiO2. Inspiringly, the photocatalyst showed high-efficiency and ultrastability for the degradation of the nonbiodegradable azo dye brilliant red X-3B under near UV irradiation with activity 4.3 times higher than that exhibited by the commercial Degussa P25. Durability tests established that the catalyst remains intact even after 15 consecutive experiments. The ultrafine metal particle size and strong metal−support interaction were considered as the key factors for the overall photocatalytic activity of the metal-semiconductor composite system

Gold Nanoparticles Intercalated into the Walls of Mesoporous Silica as a Versatile Redox Catalyst

A nanoscaled reactor framework of well-dispersed gold particles intercalated into the walls of mesoporous silica (GMS) was prepared by functionalizing silica with thioether groups. The GMS maintains mesoporous structure with uniform pores of 5.6 nm and possesses high surface area of more than 800 m2·g–1. Very recently, we reported that the GMS catalyst was very active for the oxidation of alkanes and alcohols but was also durable and recyclable. Here, we show that the catalyst is also very active for the reduction of p-nitrophenol (PNP) and methylene blue (MB) displaying catalytic activity in the reduction of PNP with Knor‑PNP of 45.9 mmol–1·s–1. The unobstructed ordered mesoporous structure of the GMS catalyst and the small size of gold nanoparticles are the main factors leading to high catalytic activities. Further, for reduction of MB, the catalytic rate of the catalyst decreases by less than 6% when recycled 10 times. Therefore, the nanoreactor framework catalyst is very robust and is readily separable and reusable, demonstrating attractive potential for practical applications