Analysis of the carbon source for diamond crystal growth

The lattice constants of diamond and graphite at high pressure and high temperature （HPHT） were calculated on the basis of linear expansion coefficient and elastic constant. According to the empirical electron theory of solids and molecules （EET）, the valence electron structures （VESs） of diamond, graphite crystal and their common planes were calculated. The relationship between diamond and graphite structure was analyzed based on the boundary condition of the improved Thomas-Fermi-Dirac theory by Cheng （TFDC）. It was found that the electron densities of common planes in graphite were not continuous with those of planes in diamond at the first order of approximation. The results show that during the course of diamond single crystal growth at HPHT with metal catalyst, the carbon sources forming diamond structure do not come from the graphite structure directly. The diamond growth mechanism was discussed from the viewpoint of valence electron structure.     

Three-dimensional fluorescence spectral characteristics of dissolved organic carbon in cave drip waters and their responses to environment changes: Four cave systems as an example in Guizhou Province,China

Understanding the responses of fluorescence spectral characteristics of cave drip waters to modern environment and climate changes is key to the reconstructions of environmental and climatic changes using fluorescence spectral characteristics of speleothems. The fluorescence spectral characteristics of dissolved organic carbon （DOC） in four active cave systems were analyzed with a three-dimensional （3D） fluorescence spectral analysis method. We found that the fluorescence types of DOC were mainly of fulvic-like and protein-like fluorescences, both in soil waters and cave drip waters. The intensity of fulvic-like fluorescence was positively correlated with the concentrations of DOC, suggesting that the DOC of cave drip waters was derived from the overlying soil layer of a cave system. Compared with the other cave systems, the variation range of the excitation and emission wavelengths for fulvic-like fluorescence of cave drip waters in Liangfeng cave system that had forest vegetation was smaller and the excitation wavelength was longer, while its fluorescence intensity varied significantly. By contrast, the excitation and emission wavelengths and fluorescence intensity for that in Jiangjun cave system that had a scrub and tussock vegetation showed the most significant variation, while its excitation wavelength was shorter. This implies that the variation of vegetation overlying a cave appears to be a factor affecting the fluorescence spectral characteristics of cave drip waters.     

Effects of water mist addition on kerosene pool fire

The use of water mist to extinguish fire is a problem of particular interest since the banning of halogen-based agents for environmental reasons. This interest is reflected in the large number of researches performed on the main fire-extinguishing mechanisms of water mist： heat extraction, oxygen displacement and attenuation of heat fluxes. In contrast, there are still little known about the chemical and some other aspects of water mist addition on the pool fire. In this paper, a phenomenological study was conducted of the effect of water mist addition on the kerosene pool fire through the measurement of the heat release rate, CO, CO2 and O2 species concentration in combustion. The experimental results show that there is a significant enhancement effect at the beginning stage of water mist addition. Then, the flame size was decreased abruptly. By physical suppression effect combined with chemical effect, the experiments＇ results are explained especially. The study of effects of water mist on pool fire will be useful for optimizing designation of water mist fire-suppression system, improving the fire suppression efficiency and extending their application field.     

Study on the electronic structure of nickel hydroxide by quantum chemical DV-Xα calculation

The electronic structures of atom clusters NiTO12H12^2＋ and NiTO12H9^- of β-Ni（OH）2 were calculated by quantum chemical DV-Xα method. By analyzing the state densities, orbital populations, net charges and electric charge density differences of the selected clusters, it was indicated that β-Ni（OH）2was not typical ionic crystal, and the bonds between Ni and O atoms had obvious covalent characteristics. The bonds between H atom and other atoms in the crystal structure were weaker, which ensured that H atoms can easily deintercalate and intercalate into β-Ni（OH）2. The structure of β-Ni（OH）2 was not changed by moderate de-intercalation of H atoms. However, with the excessive de-intercalation of H atoms, the structure of β-Ni（OH）2 changed and the electrochemical active properties were reduced.     

Differentiation of human embryonic stem cells along a hepatocyte lineage and its application in liver regeneration

Hepatocyte transplantation and bioarUficial liver （BAL） as alternatives to liver transplantation offer the possibility of effective treatment for many inherited and acquired hepatic disorders. Unfortunately, the limited availability of donated livers and the variability of their derived hepatocytes make it difficult to obtain enough viable human hepatocytes for the hepatocyte-based therapies. Embryonic stem cells （ESCs）, which could be isolated directly from the blastocyst inner cell mass, have permanent self-renewal capability and developmental pluripotency and therefore might be an ideal cell source in the treatment of hepatic discords. However, differentiation of hESCs into hepatocytes with significant numbers remains a challenge. This review updates our current understanding of differentiation of ESCs into hepatic lineage cells, their future therapeutic uses and problems in liver regeneration.     

Flow characteristics and reaction properties of carbon dioxide in microtubules and porous media

Carbon dioxide reacts with porous media while flowing through them enhancing their permeability. Its flow behavior as well as the permeability enhancement effects were studied in synthetic cores, natural cores and microtubes with an inner diameter of 5 μm. The results show that the permeability of H2O-saturated cores （containing carbonate ingredients） was enhanced by increasing the injection volume of a CO2-H2O solution. This enhancement is attributable to carbon dioxide＇s corrosion, which is justified by SEM scanning. The same phenomenon occurs with a CO2-H2O solution in microtubes, but for a different reason. The gas flow velocity of carbon dioxide in microtubes was approximately 100% faster than that of nitrogen because of the scale and the squeezing effects. Carbon dioxide molecules dissolved in water accelerate the diffusion rate of water molecules within the boundary layer, which in turn diminishes the thickness of the water film and enlarges the effective pore size. This flow behavior facilitates the injection of carbon dioxide into low-permeability reservoirs for oil-displacement and formation energy buildup purposes. This behavior also increases the potential for carbon dioxide channeling or release from the formation.     

Analysis of DNA methylation variation in wheat genetic background after alien chromatin introduction based on methylation-sensitive amplification polymorphism

During the process of alien germplasm introduced into wheat genome by chromosome engineering, extensive genetic variations of genome structure and gene expression in recipient could be induced. In this study, we performed GISH （genome in situ hybridization） and AFLP （amplified fragment length polymorphism） on wheat-rye chromosome translocation lines and their parents to detect the identity in genomic structure of different translocation lines. The results showed that the genome primary structure variations were not obviously detected in different translocation lines except the same 1RS chromosome translocation. Methylation sensitive amplification polymorphism （MSAP） analyses on genomic DNA showed that the ratios of fully-methylated sites were significantly increased in translocation lines （CN12, 20.15%; CN17, 20.91%; CN18, 22.42%）, but the ratios of hemimethylated sites were significantly lowered （CN12, 21.41%; CN17, 23.43%; CN18, 22.42%）, whereas 16.37% were fully-methylated and 25.44% were hemimethylated in case of their wheat parent. Twenty-nine classes of methylation patterns were identified in a comparative assay of cytosine methylation patterns between wheat-rye translocation lines and their wheat parent, including 13 hypermethylation patterns （33.74%）, 9 demethylation patterns （22.76%） and 7 uncertain patterns （4.07%）. In further sequence analysis, the alterations of methylation pattern affected both repetitive DNA sequences, such as retrotransposons and tandem repetitive sequences, and low-copy DNA.     

Verification of GRAPES unified global and regional numerical weather prediction model dynamic core

During the past few years, most of the new developed numerical weather prediction models adopt the strategy of multi-scale technique. Therefore, China Meteorological Administration has devoted to developing a new generation of global and regional multi-scale model since 2003. In order to validate the performance of the GRAPES （Global and Regional Assimilation and PrEdiction System） model both for its scientific design and program coding, a suite of idealized tests has been proposed and conducted, which includes the density flow test, three-dimensional mountain wave and the cross-polar flow test. The density flow experiment indicates that the dynamic core has the ability to simulate the fine scale nonlinear flow structures and its transient features. While the three-dimensional mountain wave test shows that the model can reproduce the horizontal and vertical propagation of internal gravity waves quite well. Cross-polar flow test demonstrates the rationality of both for the semi-Lagrangian departure point calculation and the discretization of the model near the poles. The real case forecasts reveal that the model has the ability to predict the large-scale weather regimes in summer such as the subtropical high, and to capture the major synoptic patterns in the mid and high latitudes.     

Direct assimilation of satellite radiance data in GRAPES variational assimilation system

Variational method is capable of dealing with observations that have a complicated nonlinear relation with model variables representative of the atmospheric state, and so make it possible to directly assimilate such measured variables as satellite radiance, which have a nonlinear relation with the model variables. Assimilation of any type of observations requires a corresponding observation operator, which establishes a specific mapping from the space of the model state to the space of observation. This paper presents in detail how the direct assimilation of real satellite radiance data is implemented in the GRAPES-3DVar analysis system. It focuses on all the components of the observation operator for direct assimilation of real satellite radiance data, including a spatial interpolation operator that transforms variables from model grid points to observation locations, a physical transformation from model variables to observed elements with different choices of model variables, and a data quality control. Assimilation experiments, using satellite radiances such as NOAA17 AMSU-A and AMSU-B （Advanced Microwave Sounding Unit）, are carried out with two different schemes. The results from these experiments can be physically understood and clearly reflect a rational effect of direct assimilation of satellite radiance data in GRAPES-3DVar analysis system.     

Relationship between Chinese speech intelligibility and speech transmission index in rooms using dichotic listening

Speech intelligibility （SI） is an important index for the design and assessment of speech purpose hall. The relationship between Chinese speech intelligibility scores in rooms and speech transmission index （STI） under diotic listening condition was studied using monaural room impulse responses obtained from the room acoustical simulation software Odeon in previous paper. The present study employs the simulated binaural room impulse responses and auralization technique to obtain the subjective Chinese speech intelligibility scores using rhyme test. The relationship between Chinese speech intelligi-bility scores and STI is built and validated in rooms using dichotic （binaural） listening. The result shows that there is a high correlation between Chinese speech intelligibility scores and STI using dichotic listening. The relationship between Chinese speech intelligibility scores and STI under diotic and dichotic listening conditions is also analyzed. Compared with diotic listening, dichotic （binaural） listening （an actual listening situation） can improve 2.7dB signal-to-noise ratio for Mandarin Chinese speech intelligibility. STI method can predict and evaluate the speech intelligibility for Mandarin Chinese in rooms for dichotic （binaural） listening.