Theoretical exploration of mechanical, electronic structure and optical properties of aluminium based double halide perovskite.

The mechanical, electronic structure and optical properties of aluminium based double halide perovskite were calculated by density functional theory. The formation energy and elastic constant confirm the stability of the cubic perovskite materials. The materials are all ductile and suitable for flexible photovoltaic and optoelectronic devices. The band gap values vary from 0.773 eV to 3.430 eV, exactly corresponding to the range of ideal band gap values for good photoresponse. The band structure analysis shows that all the materials possess small effective mass, which indicates a good transport of carriers. And these materials have a broad energy range of optical absorption for utilization and a detector of photons. Moreover, less expensive K2AgAlBr6 were investigated for comparison with materials containing a cesium element, and according to the results, is also a candidate for photoelectronic devices due to the similar properties.

Study on the properties of perovskite materials under light and different temperatures and electric fields based on DFT.

The photoelectric conversion efficiency of perovskite solar cells has improved rapidly, but their stability is poor, which is an important factor that restricts their commercial production. This paper studies the physical and chemical stability of perovskite solar cells based on first principles. It is well known that methylamido lead iodide compounds and methylamino lead iodide compounds are easily degraded into NH2CH[double bond, length as m-dash]NH2I, CH3NH3I and PbI2. First, the chemical stability of the above two perovskite-type solar cell materials is discussed by calculating the binding energy. Then, their phonon scattering lines, state density and thermodynamic properties are calculated and analyzed, and the work functions of different types of crystals along different planes such as [1 0 0], [0 1 0 0], [0 0 1] and [1 1 1] are calculated. The results show that the work function of the methylamine iodized lead compound is greater than that of the methylamidine iodized lead compound, which means that the electrons of the methylamidine iodized lead compound escape more easily and the carrier transfer efficiency is higher under the same conditions. Finally, the effects of different temperatures, different electric fields and light on the two kinds of crystal materials are analyzed. This provides theoretical guidance for us to improve the stability of perovskite materials experimentally.

cDNA cloning of glucose-6-phosphate isomerase from crucian carp (Carassius carassius) and expression of the active region as myofibril-bound serine proteinase inhibitor in Escherichia coli.

Glucose-6-phosphate isomerase (GPI) (EC 5.3.1.9) can act as a myofibril-bound serine proteinase (MBSP) inhibitor (MBSPI) in fish. In order to better understand the biological information of the GPI and its functional domain for inhibiting MBSP, the cDNA of GPI was cloned from crucian carp (Carassius carassius) with RT-PCR, nested-PCR and 3'-RACE. The result of sequencing showed that the GPI cDNA had an open reading frame of 1662bp encoding 553 amino acid residues. After constructing and comparing the three-dimensional structures of GPI and MBSP, the middle fragment of crucian carp GPI (GPI-M) was predicted as a functional domain for inhibiting MBSP. Then the crucian carp GPI-M gene was cloned and expressed in Escherichia coli. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) showed that the recombinant GPI-M (rGPI-M) with molecular mass of approximately 21kDa in the form of inclusion bodies. The rGPI-M was obtained at an electrophoresis level purity of approximately 95% after denaturation and dialysis renaturation.

[Chemical constitunents of seeds of Oroxylum indicum].

OBJECTIVE: To study the chemical constituents in the seeds of Oroxylum indicum. METHOD: Twenty compounds were isolated and purified by silica gel, and Sephadex LH-20 column chromatography, and their structures were determined by spectroscopic analysis including NMR and MS. RESULT: Twenty compounds were isolated and identified as oroxin A (1), oroxin B (2), chrysin (3), baicalein (4), quercetin (5), apigenin (6), kaempferol (7), quercetin-3-O-ara-binopyranoside (8), lupeol C9), lup-20 (29)-ene-2alpha,3beta-diol (10), pinosylvin (11), dihydropinosylvin (12), cholest-5-ene-3, 7-diol (13), rengyol (14), isorengyol (15), zarzissine (16), (E) -pinosylvin-3-O-beta-D-glucopyranoside (17), adenosine (18), sitosterol (19) and daucosterol (20). CONCLUSION: Compounds 11-13 and 15-18 were obtained from the genus Oroxylum for the first time, and except compound 18, the remaining 6 compounds were obtained from the family Bignoniaceae for the first time.