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Key message Seventy-three QTL related to grain color and tannin content were identified in Chinese sorghum accessions, and a new recessive allelic variant of TAN2 gene was discovered. Abstract Sorghum is mainly used for brewing distilled liquors in China. Since grain tannins play an important role in liquor brewing, accurately understanding the relationship between grain color and tannin content can provide basis for selection standards of tannin sorghum. We resequenced a panel of 242 Chinese sorghum accessions and performed population structure and genome-wide association study (GWAS) to identify quantitative trait locus (QTL) affecting pericarp color, testa pigment, and tannin content. Phylogenetic analysis, principal component analysis (PCA), and admixture model were used to infer population structure. Two distinct genetic sub-populations were identified according to their corresponding northern and southern geographic origin. To investigate the genetic basis of natural variation in sorghum grain color, GWAS with 2,760,264 SNPs was conducted in four environments using multiple models (Blink, FarmCPU, GLM, and MLM). Seventy-three QTL were identified to be associated for the color of exocarp, mesocarp, testa, and tannin content on all chromosomes except chromosome 5, of which 47 might be novel QTL. Some important QTL were found to colocalize with orthologous genes in the flavonoid biosynthetic pathway from other plants, including orthologous of Arabidopsis (Arabidopsis thaliana) TT2, TT7, TT12, TT16 and AT5G41220 (GST), as well as orthologous of rice (Oryza sativa) MYB61 and OsbHLH025. Our investigation of the variation in grain color and tannin content in Chinese sorghum germplasm may help guide future sorghum breeding for liquor brewing.

Sorghum is mainly used for brewing distilled liquors in China. Since grain tannins play an important role in liquor brewing, accurately understanding the relationship between grain color and tannin content can provide basis for selection standards of tannin sorghum. We resequenced a panel of 242 Chinese sorghum accessions and performed population structure and GWAS analysis to identify QTLs affecting pericarp color, testa pigment, and tannin content. Dendrogram, principal component analysis (PCA), and admixture model were used to infer population structure. Two distinct genetic sub-populations were identified according to their corresponding northern and southern geographic origin. To investigate the genetic basis of natural variation in sorghum grain color, a genome-wide association study (GWAS) with 2,760,264 SNP was conducted with multiple models (Blink, FarmCPU, GLM, and MLM). The four models identified 1090, 259, 32 and 251 SNP loci for the color of exocarp, mesocarp, testa, and tannin content, respectively. These SNPs were distributed in 440 SNP peaks. Some novel quantitative trait loci for sorghum pericarp color, testa pigments and tannin content colocalized with homologous genes in the flavonoid biosynthetic pathway from other plants, including an orthologue of maize ( Zea mays ) bz2 and homologues of Arabidopsis ( Arabidopsis thaliana ) TT2 , TT12 , and TT16 . Our investigation of the variation in grain color and tannin content in Chinese sorghum germplasm may help guide future sorghum breeding for liquor brewing.

Using surface photovoltaic and electric-field-induced surface photovoltaic techniques, as well as a CASTEP simulation method, we have studied the photo-excited and field-induced charge transfer (CT) behaviors of anatase nano-TiO2 particles adsorbed by O2, N2, and water vapor. Our results suggest that the photo-generated carriers transport process is strongly influenced by the adsorbates on the TiO2 nanoparticles. Oxygen molecules enhance the main-band-gap CT transition at 345 nm and inhibit the sub-band-gap CT transition at 419 nm. This can be explained by the 1 π g electrons in adsorbed O2 and the widened bandgap after adsorbing O2. Nitrogen molecules inhibit the main-band-gap and the sub-band-gap CT transitions differently. This can be explained by the 3 σ g and 1 π g electrons of adsorbed N2, which may cause more new surface states in between the bandgap and decrease the valence band edge of nano-TiO2, as suggested by the CASTEP simulation. The influence of adsorbed water molecule on the main-band-gap CT transition is much stronger than that on the sub-band-gap CT transition.

The photogenerated carriers’ transport and microstructure of self-assembled core–shell ZnSe/ZnS/L-Cys quantum dots (QDs), which was synthesized at room temperature, are studied via the surface photovoltaic and transient photovoltaic techniques, X-ray diffraction, high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy and ultraviolet–visible absorption spectra. The results suggest that the ZnSe nanocrystals prepared at room temperature prefer to nucleate at (111) and (220) faces, and grow a shell–ZnS at (220) face rather than at (311) face. The quantum well depth in some interface space charge region (SCR) of the QDs prepared at room temperature is smaller than that prepared at 90 °C. The evolution of the band bending from a depletion layer to an accumulation layer may occur in the graded-band-gap and at the side of the interface SCR, as compared the QDs with p-type photovoltaic characteristic synthesized at room temperature to that at 90 °C. This electron structural shift may be ascribed to the reduced quantum well depth and then an obvious resonance quantum tunneling of the QDs synthesized at room temperature.

Adjustment of the nanostructure and carrier behaviour of CdSe quantum dots (QDs) by varying the ligands used during QD synthesis enables the design of specific quantum devices via a self-assembly process of the QD core–shell structure without additional technologies. Surface photovoltaic (SPV) technology supplemented by X-ray diffractometry and infrared absorption spectroscopy were used to probe the characteristics of these QDs. Our study reveals that while CdSe QDs synthesized in the presence of and capped by thioglycolic acid, 3-mercaptopropionic acid, mercaptoethanol or α-thioglycerol ligands display zinc blende nanocrystalline structures, CdSe QDs modified by l -cysteine possess wurtzite nanocrystalline structures, because different end groups in these ligands induce distinctive nucleation and growth mechanisms. Carboxyl end groups in the ligand served to increase the SPV response of the QDs, when illuminated by hν ≥ Eg,nano-CdSe. Increased length of the alkyl chains and side-chain radicals in the ligands partially inhibit photo-generated free charge carrier (FCC) transfer transitions of CdSe QDs illuminated by photon energy of 4.13 to 2.14 eV. The terminal hydroxyl group might better accommodate energy released in the non-radiative de-excitation process of photo-generated FCCs in the ligand's lowest unoccupied molecular orbital in the 300–580 nm wavelength region, when compared with other ligand end groups.

The traditional view that the role of the composite template that is adopted in the preparation of nano-TiO2 is only for forming a pore structure and increasing the material's specific surface area is challenged by this study. The complex impact of the composite template and La-doping on the microdynamic behavior of photo-generation free charge carriers (FCCs) in the mesoporous nano-TiO2 is investigated using the transient photovoltaic (TPV) technique, supplemented by electric field-induced surface photovoltaic spectroscopy and a computer simulation method. The experimental results reveal that utilizing an appropriate composite template, such as polyethylene glycol and octadecylamine with a molar ratio of 1:1, may result in the rapid separation and prolonged diffusion distance of electron–hole pairs that were excited by a 355 nm and 50 μJ laser pulse. These may be responsible for the stronger and broader TPV response in the microsecond and millisecond regions of the La-doped nano-TiO2 in TPV spectroscopy, as compared with that for materials that used other composite templates. This response is closely related to the reduced content of the surface state located at 367 nm. A suitable level of La-doping, however, was only responsible for the stronger and broader TPV response in the microsecond region of the spectrum of the nano-TiO2. The computer simulation results confirm that the photo-generation FCCs microdynamic characteristics in the microsecond region may partially originate from the state density distribution of both the d-electron in the antibonding orbital and the p-electron in the bonding orbital moving up to higher levels, and from a broader band-gap after La-doping in the anatase lattice cell.

A mesoporous La-doped nano-TiO2 was prepared by the sol–gel method using polyethylene glycol as the template. A combination of surface photovoltaic (SPV) and photoacoustic technologies, aided by laser Raman technology, was used to probe the photoexcited charge transfer transition behaviors in the surface space charge region of the sample. The results confirm that the lanthanum doping was responsible for inhibiting the transformation from the anatase to rutile form and grain growth, thus strengthening the microstructure that was formed after removal of the template clearly. The experiment reveals that appropriate La-doping resulted in an obvious increase in the SPV response. By contrast, the remainder of the template had a somewhat negative effect on the SPV response of the samples. The effect of both the La-doping and the removal of the template on the nonradiative de-excitation process of the main band-gap can be negligible, in spite of the nonradiative de-excitation processes of the sub-band-gap of the La-undoped sample, in which the surface states possessed the donor characteristic, being more obvious than that of the La-doped samples. The results showed that the electron–phonon interactions on the surfaces resulting from the nonradiative de-excitation process were closely dependent on the effect of quantum confinement of the mesoporous nano-TiO2.

A microdynamics study of high-quality CdTe/ligand self-assembled quantum dots (QDs) is significant because it is closely related to the energy transformation among specific quantum states, such as the electron and vibration levels of an elementary reaction. Transient photovoltaic (TPV) technology was used to probe the microdynamics behavior of the photogenerated carriers in the QDs. The TPV polarity of the nanocrystalline CdTe particles depended on the type of capping ligand used [3-mercaptopropionic acid (MPA) or β-mercaptoethylamine (MA)] because of a quantum tunneling effect. This resulted in a negative TPV polarity of the MPA samples upon illumination with a laser pulse of 532 nm and excitation intensity of 50 μJ, the opposite to the situation for the MA sample. The effect of the concentration of Cd 2+ cations on the separation and recombination rates of the photo-induced free charge carriers of the CdTe/MPA self-assembled QDs was negligible. The different chemical bonds that formed at the interface between the core-CdTe nanoparticles and the capping ligand led to the change in the intensity of the photoacoustic signal in the 550–800 nm region caused by the non-radiative de-excitations as compared to the CdTe QDs capped by MA with that capped by MPA, and to the differences in the Raman scattering between the two samples. The property of those lattice vibration quantum states locating at the Brillouin zone boundary or near the Brillouin zone boundary was associated to a great extent with the formation of the shell-CdS in between the core-CdTe and the capping ligand according to the computer simulation results.

Surface photovoltage spectroscopy and photoacoustic spectroscopy were combined to explore the surface electron structures of anatase TiO2 nanoparticles and their reorganization induced by the presence of the rutile phase. The presence of the rutile phase on the nanoparticles created a new surface state T i 3 d ( s 2 ) 3 + , at the same time decreased the state density of T i 3 d ( s 1 ) 3 + . The critical weight fraction of the rutile phase was demonstrated 8 wt%, above which the surface electron structure of anatase TiO2 nanoparticles was turned from anatase to rutile-like. It was found after the relationship of the photogenic free charge carriers and the nonradiative transitions was confirmed that the surface electron reorganization greatly suppressed the nonradiative transitions.

A novel type of hollow glass waveguide with β-SiC dielectric films was manufactured by a modified chemical vapor deposition method. FTIR absorption spectra and SEM results show that the change of film structure is responsible for the phenomena of the blue shift and the narrow width of the fundamental absorption band of β-SiC, and that the microfissures at the films provide the heterocrystallization centers for promoting the formation of β-SiC crystal. The influences of the concentration of hydrogen gas passed through the system and the reaction temperature are discussed with regard to the film structure.

Electron transport types and photovoltage gas-sensitive characters of nano-La1−xSrxFeO3 were probed by the vacuum adsorptive surface photovoltage technique. The results show that the band distortion and the increased anion vacancy caused by doping with a little Sr2+ ions in the nanomaterial are of advantage to form new exciton levels and the localized photogenic free charge carriers, to promote the separation of exciton pairs with increasing sensor gas pressure, and to increase quantum-optical efficiency as result of the effect of surface and quantum confinement.

The electron transport types and photovoltage gas-sensitive characters of nano-LaFeO3 surface adsorbed by the active gas are probed by surface photovoltage and electric field induced surface photovoltage techniques. The results show that nano-LaFeO3 has the effects of surface and quantum confinement, which results in producing a new surface state band ca. 0.61 eV at the top of the valence band and the photogenic exciton pair in relevant transition. A plot of optimum phase of SPV response versus particle size of the nanocrystalling material is obtained.

The effects of surface and quantum confinement on nano-LaFeO 3 surface adsorbed by the sensor gas are probed by vacuum adsorptive surface photovoltage technique. The quantum confinement effect depends exponentially on the pressure of the sensor gas. There are two main ways of charge transfer transition on the adsorbed nano-LaFeO 3 surface.

Nanoparticles of the TiO2/ZnO composite photocatalysts were prepared via sol-gel process. The crystalline structure, morphology, thermal stability, and pore structure properties of the composite photocatalysts were characterized by XRD, FE-SEM, TG-DTA, and N2physical adsorption measurements. The photocatalytic activity of the composite catalysts was evaluated by photocatalytic degradation reaction of methyl orange (MO) in aqueous solution. The best preparation parameters for the composite photocatalysts were obtained through systematical experiments. Furthermore, the photocatalytic degradation reaction of aqueous MO solution followed the first-order reaction kinetics; the relative equation can be described asln(C0/C)=0.5689t, and the calculated correlation constant (R2) is 0.9937 for the calibration curve.

By combining surface photovoltaic and photoacoustic techniques, we probed the photogenerated charge transport channels of 3-mercaptopropionic acid (MPA)- and 2-mercaptoethylamine (MA)-capped crystalline CdTe nanoparticles on illumination with UV-near IR light. The results experimentally confirmed the presence of a CdS shell outside the CdTe core that formed through the self-assembly and decomposition of mercapto ligands during CdTe preparation. The data revealed that the CdS layer was partly responsible for the deexcitation behavior of the photogenerated carriers, which is related to the quantum tunnel effect. Experiments demonstrated that two quantum wells were located at wavelengths of 440 and 500 nm in buried interfacial space–charge regions, whereas the formation of a ligand layer obstructed charge transfer transitions of the core CdTe nanoparticles to a certain extent.

The combination of the surface photovoltaic and the photoacoustic techniques was used for probing the surface electron-phonon interaction (SEPI) and the mechanism of nonradiative transitions of the three typical nanocrystalline semiconductors at room temperature upon illumination of UV. near IR light. The results showed that the SEPIs on the La-doped nano-TiO2 and the nano-La1-xSrxFeO3 had nothing to do with the charge transfer transitions of the main bandgap. The SEPI of the nano-La1-xSrxFeO3 depended close on both exciton transitions and crystal-field transitions upon illumination at the photon energy hnu was smaller than the bandgap Eg, La 1-x Sr x FeO 3. The photogenic free charge carriers at hnu

A new type of the double layers polycrystal dielectric film in the quartz capillary has been fabricated. The first film is composed of nanoscale germanium dioxide obtained from controlling reaction temperature, gas flow rate and the proportion of reactants, and the second film is metal layer that has high refractive index at infrared region. So the dual-layer thin film has very high reflectivity at the wavelength range of 8-11 .6 µ m. The hollow-core optical fiber with this film on inner wall can transmit over 400 watts of cw carbon dioxide laser power or the pulse carbon dioxide laser with pulse width of 0.1 second and peak-power of 1000 watts, and transmission loss is less than O.6dB/m at 10.6 µ m in transmitting high power. The transmitting laser power fibers can be applied in medical treatment, mechanical process or the relevant scientific research etc.