Haoquan Hu

Preparation of carbon adsorbents with high surface area and a model for calculating surface area

Abstract Carbon adsorbents (CAs) were made by heat treatment of a mixture of coal char and KOH under the protection of an inert argon flow and the influence of operating conditions on the properties of adsorbents was investigated. Changes in the characteristics of graphitic crystallites during manufacture by X-ray diffraction (XRD) analysis indicated that disappearance of the peak corresponding to 002 faces correlated to high specific surface area. Based on the experimental results, a new model of graphitic crystallites containing hydrogen atoms is proposed to calculate idealized surface area of CAs. With this model, the idealized surface areas of CA can be precisely calculated with the aid of X-ray diffraction. In this way, some experimental problems can be overcome, such as the difficulty to measure specific surface area with N 2 adsorption when pore diameters are too small and overestimation when surface areas are too large.

Analysis of chromosomal and organellar DNA of somatic hybrids between Triticum aestiuvm and Haynaldia villosa Schur.

Abstract. Intergeneric somatic hybridization between wheat (cv. Jinan 177) protoplasts that have 24–28 chromosomes and Haynaldia villosa protoplasts containing 11–14 chromosomes was carried out by the polyethylene glycol (PEG) method. A high frequency of hybrid calli and plants were obtained from the fusion products, as revealed by cytological and biochemical techniques and by PCR analysis of 5S rDNA spacer sequences. GISH (genomic in situ hybridization) analysis confirmed the presence of chromosomes from both parents in the hybrid clones and the common occurrence of translocations between them. The RFLP analysis of the organellar DNA using mitochondrion- and chloroplast-specific probes revealed that mitochondria from both parents existed in the cells of hybrid calli and their recombination, whereas chloroplasts segregated and recombined randomly. The gross morphology of hybrid plants resembled that of wheat, but the gross morphology of their ovaries and anthers were intermediate between those of the two parents. The relationship between hybrid plant regeneration and the balance of genetic materials in hybrid clones is discussed.

Extraction of lignite with water in sub- and supercritical states

Abstract On a semi-continuous apparatus, Dayan lignite was extracted with water in sub- and supercritical states. The experiments were carried out to investigate the effect of temperature on extract formation rate, extract yields and product components at different pressures and end temperatures. The results indicated that the extract formation rate has a maximum with the variation of temperature. The temperature corresponding to the maximum extract formation rate, changing with the pressure, is between 400 and 450°C. The extraction yields vary with the conditions. With the increase of pressure, the conversion and extract yield increase. With the increase of end temperature, the conversion also increases, but the increment is mainly gas and light oil. The main fraction in extract is preasphaltene and the main gas component is CO 2 .

Effect of solvent swelling on liquefaction of Xinglong coal at less severe conditions

Xinglong coal, a sub-bituminous coal, was swollen with pyridine or tetrahydrofuran followed by liquefaction in a 70-ml autoclave apparatus. The experiments were carried out to investigate the effects of temperature, solvent, atmosphere and catalyst on the liquefaction of solvent-swollen coal and untreated coal. The results indicate that the conversion of coal could be effectively improved in the temperature range of 320–420°C by swelling pretreatment. Molecular hydrogen shows no contribution to coal conversion during the liquefaction of pyridine-swollen coal in the absence of a catalyst and in the presence of hydrogen donor solvent such as tetralin. With the addition of a catalyst, the liquefaction conversion of pyridine-swollen coal is higher in H2 than that in N2. The swelling pretreatment of coal can improve the liquefaction yields, weaken the dependence of the process on the presence of molecular hydrogen and the hydrogen donation ability of the solvent, and increase the conversion of coal liquefaction.

Photosynthetic performance and acclimation of Incarvillea delavayi to water stress

The photosynthetic performance and related leaf traits of Incarvillea delavayi Bur. et Franch were studied at different water regimes to assess its capacity for photosynthetic acclimation to water stress. The initial response of I. delavayi to water stress was the closure of stomata, which resulted in down-regulation of photosynthesis. The stomatal limitation (SL) represented the main component to photosynthetic limitations but non-stomatal limitation (NSL) increased quickly with the increasing water stress, and had similar magnitude to SL under severe water stress (soil moisture 25–30 % of field capacity). Chlorophyll (Chl) a fluorescence parameters characterizing photosystem (PS) 2 photochemical efficiency (ΦPS2), electron transport rate (J) and photochemical quenching (qP) decreased with the increasing water stress, indicating impaired photosynthetic apparatus. However, the water-stressed plants had a increased mesophyll CO2 diffusional conductance, Chl a/b ratio, leaf nitrogen partitioning in RuBPCO and bioenergetics in later grown parts, indicating that I. delavay had a substantial physiological plasticity and showed a good tolerance to water stress.

Investigation of extracts of coal by supercritical extraction

Supercritical extraction of Leping coal was isothermally carried out with toluene and its co-solvent at 335–425°C5–10 MPa in a semi-continuous apparatus. The results indicated that extraction conditions affected the elemental composition, thermogravimetric characteristics and group components of extracts and their fractions. The yield of extract at 380°C with toluene reached a maximum 64 wt% (in daf coal) containing 31 wt% oil which included aliphatics 22 wt%, aromatics 20 wt% and polar compounds 39 wt%. HC atomic ratio of oil in such an extract was 1.38 and its weight loss at 300°C was 30%. Analysis of i.r. and 1H-n.m.r. spectra was employed to characterize the coal extract and its fractions.

Preparation of mesoporous activated carbons from coal liquefaction residue for methane decomposition

Abstract Mesoporous activated carbons were prepared from direct coal liquefaction residue (CLR) by KOH activation method, and the experiments were carried out to investigate the effects of KOH/CLR ratio, solvent for mixing the CLR and KOH, and carbonization procedure on the resultant carbon texture and catalytic activity for catalytic methane decomposition (CMD). The results showed that optimal KOH/CLR ratio of 2: 1; solvent with higher solubility to KOH or the CLR, and an appropriate carbonization procedure are conductive to improving the carbon pore structure and catalytic activity for CMD. The resultant mesoporous carbons show higher and more stable activity than microporous carbons. Additionally, the relationship between the carbon textural properties and the catalytic activity for CMD was also discussed.

Kinetic study of supercritical extraction of oil shales

Abstract The kinetics of supercritical toluene extraction of seven oil shales was studied in a semi-continuous apparatus using a non-isothermal technique. A new method is proposed for determining the order of reaction. An integral method was used to determine the activation energy and pre-exponential factor. The results indicate that the extraction process may be described by a first order kinetic equation with respect to the extractable matter present in the reaction system, and may consist of two stages which are controlled by chemical reactions. These stages include the decomposition of kerogen or bitumen and dissolution of the decomposition products. The temperature range from about 400 to 450°C, in which there is a higher rate of extract formation, has an activation energy between 130 and 190 kJ mol −1 and a pre-exponential factor between 10 7 and 10 11 s −1 . Both the activation energies and the pre-exponential factors show good linear relations with the kerogen content or volatile matter of the oil shales.

Integrated process of coal pyrolysis and CO2 reforming of methane with and without using dielectric barrier discharge plasma

ABSTRACT The integrated processes of Shenmu subbituminous coal pyrolysis and CO2 reforming of methane over catalyst (Ni/SiO2) with and without using dielectric barrier discharge plasma (ICCP and ICCC) were carried out to check the effectiveness of the integrated process on improving the tar yield of coal pyrolysis. The effects of the pyrolysis temperature and time on product yields were investigated. The results indicate that both the ICCC and ICCP have an effect on increasing the tar yield compared with coal pyrolysis under N2 or H2. The tar yield increases with the increase of pyrolysis temperature and time in the ICCC, while relatively lower pyrolysis temperature and shorter pyrolysis time is preferable in the ICCP. The highest tar yield is 24.8 wt% at 600°C for 22 min in the ICCC and that is 23.7 wt% at 500°C for 7 min in the ICCP.

Electric transport coefficients in highly epitaxial LaBaCo2O5 + δ films with “p-to-n” transition induced by oxygen deficiency

Electric transport coefficients such as carrier type, density, and mobility are the important physical parameters in designing functional devices. In this work, we report the study on the electric transport coefficients of the highly epitaxial LaBaCo2O5 + δ (LBCO) films, which were discussed as a function of electric conductivity for the first time and compared with the results calculated by the theory for mixed conduction. The mobility in the LBCO films was determined to be ∼0.85 and ∼40 cm2/V s for holes and electrons, respectively, and the density of p-type carriers strongly depends on the oxygen deficiency. Solid evidence is presented to demonstrate that the oxygen deficiency cannot make LBCO materials changed from p- to n-type. The n-type conduction observed in experiment is a counterfeit phenomenon caused by the deficiency in Hall measurement, rather than a realistic transition induced by oxygen deficiency. In addition, the temperature-dependent conductivity was discussed using the differential coef...