Phase Equilibria and Thermodynamics in the Al2O3–SiO2 System—Modeling of Mullite and Liquid

The Al₂O₃–SiO₂ system has been reassessed using a solution model for mullite extending from sillimanite to a hypothetical state of alumina. The property of sillimanite, to be used to describe one of the end-members, was extracted from an analysis of the T – P phase diagram for Al₂SiO₅ polymorphs. It was possible to represent the information on the range of stability of mullite, including some showing that mullite extends to higher SiO₂ contents than represented by the composition of 3:2 mullite. An attempt was made to model the liquid with the ionic two-sublattice model using a new species AlO₂⁻¹. The pressure dependence of Al₂SiO₅ polymorphs was optimized by a new model recently implemented in Thermo-Calc.     

千鹅冲铜钼矿床地球物理特征及找矿模型

大别山北麓千鹅冲铜钼矿是斑岩型矿床,矿体、控矿构造、岩浆岩、赋矿地层以及周围地质体之间存在某种物理性能差异,具有明显的地球物理异常特征。对此,在对矿床地球物理特征分析的基础上,建立了该区域的地球物理找矿模型,以期为正在进行中的大别山地区多金属成矿带的找矿工作提供参考。     

Effect of the Sapphire-Nitridation Level and Nucleation-Layer Enrichment with Aluminum on the Structural Properties of AlN Layers

The effect of atomic aluminum deposited onto sapphire substrates with different nitridation levels on the quality of AlN layers grown by ammonia molecular-beam epitaxy is investigated. The nitridation of sapphire with the formation of ~1 monolayer of AlN is shown to ensure the growth of layers with a smoother surface and better crystal quality than in the case of the formation of a nitrided AlN layer with a thickness of ~2 monolayers. It is demonstrated that the change in the duration of exposure of nitrided substrates to the atomic aluminum flux does not significantly affect the parameters of subsequent AlN layers.     

What Are Quantum States?

We present three strong arguments against the ontic interpretation of quantum states. We then show that the appropriate alternative is not an epistemic interpretation, but viewing quantum states as representing the available knowledge about the potentialities of a quantum system from the perspective a of a particular point in space. Unlike ordinary knowledge, which requires a knower, available knowledge can be assumed to be present regardless of a knower. The relationship between “perspectives on potentialities” and “the potentialities themselves” is clarified.     

Top-down characterization of nucleic acids modified by structural probes using high-resolution tandem mass spectrometry and automated data interpretation

A top-down approach based on sustained off-resonance irradiation collision-induced dissociation (SORI-CID) has been implemented on an electrospray ionization (ESI) Fourier transform mass spectrometer (FTMS) to characterize nucleic acid substrates modified by structural probes. Solvent accessibility reagents, such as dimethyl sulfate (DMS), 1-cyclohexyl-3-(2-morpholinoethyl)carbodiimide metho-p-toluenesulfonate (CMCT), and beta-ethoxy-alpha-ketobutyraldehyde (kethoxal, KT) are widely employed to reveal the position of single- vs double-stranded regions and obtain the footprint of bound proteins onto nucleic acids structures. Established methods require end-labeling of the nucleic acid constructs, probe-specific chemistry to produce strand cleavage at the modified nucleotides, and analysis by polyacrylamide gel electrophoresis to determine the position of the susceptible sites. However, these labor-intensive procedures can be avoided when mass spectrometry is used to identify the probe-induced modifications from their characteristic mass signatures. In particular, ESI-FTMS can be directly employed to monitor the conditions of probe application to avoid excessive alkylation, which could induce unwanted distortion or defolding of the substrate of interest. The sequence position of the covalent modifications can be subsequently obtained from classic tandem techniques, which allow for the analysis of individual target adducts present in complex reaction mixtures with no need for separation techniques. Selection and activation by SORI-CID has been employed to reveal the position of adducts in nucleic acid substrates in excess of 6 kDa. The stability of the different covalent modifications under SORI-CID conditions was investigated. Multiple stages of isolation and activation were employed in MS(n)() experiments to obtain the desired sequence information whenever the adduct stability was not particularly favorable, and SORI-CID induced the facile loss of the modified base. A new program called MS2Links was developed for the automated reduction and interpretation of fragmentation data obtained from modified nucleic acids. Based on an algorithm that searches for plausible isotopic patterns, the data reduction module is capable of discriminating legitimate signals from noise spikes of comparable intensity. The fragment identification module calculates the monoisotopic mass of ion products expected from a certain sequence and user-defined covalent modifications, which are finally matched with the signals selected by the data reduction program. Considering that MS2Links can generate similar fragment libraries for peptides and their covalent conjugates with other peptides or nucleic acids, this program provides an integrated platform for the structural investigation of protein-nucleic acid complexes based on cross-linking strategies and top-down ESI-FTMS.     

The sharpness of melting maxima

The shape of melting maxima for strictly stoichiometric phases is examined by computer calculations. For a simplified case, it is found that such maxima look sharp, in apparent violation of Konovalov’s rule, if the Gibbs energy of formation of the phase is −20T _m J/mole of atoms or lower (more negative).     

Effect of gate length in InAs/AlSb HEMTs biased for low power or high gain

The effect of gate-length variation on DC and RF performance of InAs/AlSb HEMTs, biased for low DC power consumption or high gain, is reported. Simultaneously fabricated devices, with gate lengths between 225 nm and 335 nm, have been compared. DC measurements revealed higher output conductance g_ds and slightly increased impact ionization with reduced gate length. When reducing the gate length from 335 nm to 225 nm, the DC power consumption was reduced by approximately 80% at an f_T of 120 GHz. Furthermore, a 225 nm gate-length HEMT biased for high gain exhibited an extrinsic f_T of 165 GHz and an extrinsic f_max of 115 GHz, at a DC power consumption of 100 mW/mm. When biased for low DC power consumption of 20 mW/mm the same HEMT exhibited an extrinsic f_T and f_max of 120 GHz and 110 GHz, respectively.     

Improved lean deNOx performance of Cu-ZSM-5 through alternative synthesis conditions for ZSM-5

A series of ZSM-5 samples with similar SiO₂/Al₂O₃ ratio was synthesised using different aluminum sources and by including varying amounts of calcium hydroxide during the synthesis. The samples were subsequently ion-exchanged with Cu-ions, and evaluated with respect to deNOx activity in the absence and presence of water. The choice of aluminum source and the presence of calcium hydroxide during the zeolite synthesis affected the lean deNOx activity of Cu-ZSM-5.     

双歧杆菌发酵中国黑米口服液的研制

以中国黑米为主要原料，制作发酵培养基，采用耐氧两歧双歧杆菌进行发酵扩大培养，以双歧杆菌发酵中国黑米口服液。应用该口服液对腹泻、消化不良病人进行治疗观察，疗效明显