Modeling of temperature sensor built on thin silicon on insulator using advanced carrier-mobility model

An analytical device model to study the characteristics of the temperature sensor built on thin silicon film was developed. The device had higher maximum operating temperature due to larger minority-carrier exclusion length. The carrier-concentration distribution in the minority-exclusion region, exclusion length and the temperature dependence of the sensor resistance of the model was verified by device simulation. The model can be used to study the principle of the minority-carrier exclusion effect and also to guide the design of temperature sensors built on thin silicon film for high-temperature applications.published_or_final_versio

Influence of amendments on soil structure and soil loss under simulated rainfall China’s loess plateau

Macromolecule polymers are significant types of chemical amendments because of their special structure, useful functions and low cost. Macromolecule polymers as soil amendment provide new territory for studying China’s agricultural practices and for soil and water conservation, because polymers have the ability to improve soil structure, increase rainfall penetration and control slope runoff. Through indoor laboratory experiments and outdoor artificial rainfall simulations, this study applied different consistencies of three amendments; polypropylene acid (PPA), polythene alcoholic (PTA) and urea-formaldehyde poly-condensate (UR) to China’s Loess and determined their effects on soil physical properties and on runoff-sediment yield. The results indicate that as a result of applying the amendments, (1) the water-stable soil aggregates content increases by 17.3%, the soil permeability increases by 41.8%, the soil density decreases by 11.2% and the soil water content increases by 28.0% compared to the control; (2) three amendment applied on sloping land can delay runoff and decrease runoff velocity; decrease erosive forces of raindrop impact and flowing water, reduce surface crusting and improve water infiltration, delay runoff engenderation and decrease runnoff velocity and soil erosion yield. Finally, this study also ascertained optimal application quantities and the most effective sort in three amendments, which PPA is most effective at lowering surface runoff, reducing soil loss and increasing soil penetration. These three amendments have broad potential for soil and water conservation; however, the duration of their effect and the optimal application quantities need to be researched further.Key words: Amendment, Runoff-Sediment Yield, Soil Physical Properties, Soil erosio

Pyrolysis/reforming of rice husks with a Ni–dolomite catalyst: Influence of process conditions on syngas and hydrogen yield

The influence of process conditions on the production of syngas and H2 from biomass in the form of rice husks was investigated using a two-stage pyrolysis/catalytic reforming reactor. The parameters investigated were, reforming temperature, steam flow rate and biomass particle size and the catalyst used was a 10 wt.% Ni–dolomite catalyst. Biomass was pyrolysed in the first stage, and the product volatiles were reformed in the second stage in the presence of steam and the Ni–dolomite catalyst. Increase in catalyst temperature from 850 °C to 1050 °C marginally improved total syngas yield. However, H2 yield was increased from 20.03 mmol g−1 at 850 °C to 30.62 mmol g−1 at 1050 °C and H2 concentration in the product gas increased from 53.95 vol.% to 65.18 vol.%. Raising the steam flow rate increased the H2 yield and H2 gas concentration. A significant increase in H2:CO ratio along with a decrease in CO:CO2 ratio suggested a change in the equilibrium of the water gas shift reaction towards H2 formation with increased steam flow rate. The influence of particle size on H2 yield was small showing an increase in H2 production when the particle size was reduced from 2.8–3.3 to 0.2–0.5 mm

When Neil Smith Met Pierre Bourdieu in Nanjing, China: Bringing Cultural Capital into Rent Gap Theory

In this paper, we expand rent-gap theory in conceptual and territorial terms. Hitherto, the theory has, as Neil Smith intended, been used in an economic sense; we argue here, borrowing ideas from Pierre Bourdieu, that in the competitive environment of Chinese education, a rent gap in cultural capital is created which can later be converted into economic capital. The process we identify is triggered by the purchase of an apartment in a catchment zone, crucial to obtaining entry into a prestigious ‘key’ school in most Chinese cities. This leads to apartments changing hands for high prices despite generally being old and dilapidated. The rent gap in cultural capital occurs when parents forego potential short-term gains to capitalize on the long-term benefits of a superior education. This is contrasted here with a somewhat more conventional scenario, where property developers exploit a rent gap on suburban apartments built in the catchment of branch ‘key’ schools

The underperformance of the growth enterprise market in Hong Kong

This paper examines the stock return performance of the IPO stocks which are listed on the Growth Enterprise Market (GEM) in Hong Kong. By using several benchmarks, over 3 years, this paper finds that the results produced are sensitive to the benchmark employed. The two factors causing the underperformance of GEM stocks are the `technology boom and `IPO effects. This suggests that appropriate benchmarks are very important for assessing the performance of newly issued stocks. The results of the cross-sectional analyses suggest that the Hong Kong GEM is a unique market. Since at least 70 percent of the IPO stocks listed on theGEMare technology stocks, the `technology factor outweighs the various hypotheses advocated by previous researchers to explain the poor performance of newly listed stocks

Lithium chloride reinforces the regeneration-promoting effect of chondroitinase ABC on rubrospinal neurons after spinal cord injury

After spinal cord injury, enzymatic digestion of chondroitin sulfate proteoglycans promotes axonal regeneration of central nervous system neurons across the lesion scar. We examined whether chondroitinase ABC (ChABC) promotes the axonal regeneration of rubrospinal tract (RST) neurons following injury to the spinal cord. The effect of a GSK-3β inhibitor, lithium chloride (LiCl), on the regeneration of axotomized RST neurons was also assessed. Adult rats received a unilateral hemisection at the seventh cervical spinal cord segment (C7). Four weeks after different treatments, regeneration of RST axons across the lesion scar was examined by injection of Fluoro-Gold at spinal segment T2, and locomotor recovery was studied by a test of forelimb usage. Injured RST axons did not regenerate spontaneously after spinal cord injury, and intraperitoneal injection of LiCl alone did not promote the regeneration of RST axons. Administration of ChABC at the lesion site enhanced the regeneration of RST axons by 20%. Combined treatment of LiCl together with ChABC significantly increased the regeneration of RST axons to 42%. Animals receiving combined treatment used both forelimbs together more often than animals that received sham or single treatment. Immunoblotting and immunohistochemical analysis revealed that LiCl induced the expression of inactive GSK-3β as well as the upregulation of Bcl-2 in injured RST neurons. These results indicate that in vivo, LiCl inhibits GSK-3β and reinforces the regeneration-promoting function of ChABC through a Bcl-2-dependent mechanism. Combined use of LiCl together with ChABC could be a novel treatment for spinal cord injury.published_or_final_versio

Characterization and evaluation of Ni/SiO catalysts for hydrogen production and tar reduction from catalytic steam pyrolysis-reforming of refuse derived fuel

A series of Ni/SiO catalysts have been prepared and investigated for their suitability for hydrogen production and tar reduction in a two-stage pyrolysis-reforming system, using refuse derived fuel (RDF) as the raw material. Experiments were conducted at a pyrolysis temperature of 600°C, and a reforming temperature of 800°C. The product gases were analysed by gas chromatography (GC) and the condensed fraction was collected and quantified using gas chromatography-mass spectrometry (GC-MS). The effects of the catalyst preparation method, nickel content and the addition of metal promoters (Ce, Mg, Al), were investigated. Catalysts were characterised using BET surface area analysis, temperature programmed oxidation (TPO), and scanning electron microscopy (SEM). The TPO and SEM analysis of the reacted catalysts showed that amorphous type carbons tended to be deposited over the Ni/SiO catalysts prepared by impregnation, while filamentous type carbons were favoured with the sol-gel prepared catalysts. The influence of catalyst promoters (Ce, Mg, Al) added to the Ni/SiO catalyst prepared by the sol-gel method was found not to be significant, as the H production was not increased and the tar formation was not reduced with the metal-added catalyst. The highest H concentration of 57.9vol.% and lower tar amount produced of 0.24mg/g; were obtained using the 20wt.% Ni/SiO catalyst prepared by sol-gel. On the other hand a low catalytic activity for H production and higher tar produced were found for the impregnated series of catalysts, which might be due to the smaller surface area, pore size and due to the formation of amorphous carbons on the catalyst surface. Alkenes and alcohol functional groups were mainly found in the analysed tar samples, with major concentrations of styrene, phenol, indene, cresols, naphthalene, fluorene, and phenanthrene

Production and application of carbon nanotubes, as a co-product of hydrogen from the pyrolysis-catalytic reforming of waste plastic

Hydrogen production from waste plastics is an important alternative for managing waste plastics. This work addresses a promising technology for co-producing high value carbon nanotubes (CNTs) in addition to the production of hydrogen; thus significantly increasing the economic feasibility of the process. Catalyst design is a critical factor to control the production of hydrogen and CNTs. NiMnAl catalysts, prepared by a co-precipitation method, with different metal molar ratios were developed and investigated using a two-stage fixed-bed reactor. It was found that the NiMnAl catalyst with the higher Mn content produced a higher yield of carbon (57.7 wt.%). Analysis of the carbon on the NiMnAl catalysts showed it to consist of ∼90 wt.% of carbon nanotubes. The CNTs were recovered from the catalyst and added at 2 wt.% to LDPE plastic to form a composite material. The tensile and flexural strength and the tensile and flexural modulus of the CNT composite material were significantly improved by the addition of the recovered CNTs. Thus it is suggested that cost-effective CNTs could be produced from waste plastics as by-product of the production of hydrogen, enhancing the potential applications of CNTs in the composite industry

Hydrogen production from pyrolysis catalytic reforming of cellulose in the presence of K alkali metal

The inherent alkaline metals in biomass material are known to be volatile during biomass pyrolysis. However, there are very limited works about the investigation of the influence of alkaline metal on hydrogen production from downstream catalytic reforming of pyrolysis vapors. In this study, the influence of volatile K inside the cellulose sample was investigated in terms of hydrogen production and catalyst stability using a two-stage fixed-bed reaction system in the presence of a Ni/Al2O3 catalyst. When the content of K in the cellulose sample was increased from 0 to 15%, the deposition of K on the surface of the reacted catalyst was kept constant at around 0.5 wt.% in terms of the weight of the catalyst. The life time test shows that hydrogen production was around 28 (mmol g-1 cellulose) for each experiment, when the catalyst was reused 5 times using the pure cellulose sample. However, the hydrogen production was significantly reduced to 22 (mmol g-1 cellulose) after the catalyst was reused 5 times with the 2.5% K/cellulose sample. X-Ray Fluorescence analysis shows that the reduce hydrogen production might be ascribed to the increase of the K deposition on the surface of the reused catalyst

Development of Fe-Promoted Ni–Al Catalysts for Hydrogen Production from Gasification of Wood Sawdust

The production of renewable hydrogen-enriched gas from biomass waste is a promising technology for the development of a sustainable economy and society. Until now, there are still challenges of the technology in terms of the efficiency of hydrogen production. A catalyst is known and has been tested to enhance hydrogen production from biomass gasification, in particular, using Ni-based catalysts, which have high reactivity for hydrogen production and are cost-effective. However, developing a Ni-based catalyst with high thermal stability and resistance of coke deposition on the surface of the catalyst is still a challenging topic. In this work, Ni–Al catalysts doped with low-cost Fe metal were investigated for hydrogen-enriched syngas production from gasification of biomass using a two-stage fixed bed reactor. NiO–Fe2O3–Al2O3 catalysts with various Ni/Fe molar ratios (9:1, 8:2, 6:4, 5:5, 4:6, 2:8, and 1:9) were studied, aiming to understand the influence of Fe addition on the production of hydrogen and the catalyst stability in terms of coke deposition on the surface. X-ray diffraction, temperature-programmed reduction, and transmission electron microscopy (TEM) analysis of the fresh catalysts showed that nanoparticles (mainly NiAl2O4 spinel phase and Al2O3, ∼5 nm) were identified in the catalysts. High dispersion of metal particles was obtained using a co-precipitation method of catalyst preparation. With the increase of Fe addition, hydrogen production was reduced from around 11 to 8 mmol of H2 g–1 of biomass. However, the addition of Fe to the Ni-based catalyst significantly reduced the amount of coke deposited on the surface of the catalyst. The H2/CO molar ratio was maximized to 1.28 when the Ni/Fe molar ratio was 1:1. In addition, sintering of metal particles was not observed through the TEM analysis of the fresh and reacted catalysts