Water Dissociation Kinetic-Oriented Design of Nickel Sulfides via Tailored Dual Sites for Efficient Alkaline Hydrogen Evolution

The reaction kinetics of alkaline hydrogen evolution reactions (HER) is a trade-off between adsorption and desorption for intermediate species (H₂O, OH, and H_ads). However, due to the complicated correlation between the intermediates adsorption energy and electronic states, targeted regulating the adsorption energy at the atomic level is not comprehensive. Herein, nonmetals (B, N, O, and F) are used to modulate the adsorption energy and electronic structure of Ni₃S₄, and propose that H₂O and OH adsorption energy are correlate directly with d-band center (ε_d) of transition metal Ni, and H_ads adsorption energy has a linear dependence on p-band center (ε_p) of nonmetal S. Direct experimental evidence is offered that in all nonmetals doping samples, Tafel slope and exchange current density can be improved regularly with the ε_d and ε_p, and F-Ni₃S₄ shows the optimum activity with tiny overpotential 29 and 92 mV for harvesting current density 10 and 100 mA cm⁻², respectively. Furthermore, the micro-kinetics analysis and density functional theory calculations verify that F-doping can efficiently reduce the energy barrier of the Volmer step, eventually accelerating the HER kinetics. This work provides atomic-level insight into the structure-properties relationship, and opens an avenue for kinetic-oriented design of alkaline HER and beyond.     

Underwater light polarization and radiance fluctuations induced by surface waves

The underwater light field is an ever-changing environment. Surface waves induce variability in the radiance and the light's polarization. We examined the dependence of the polarization fluctuations associated with diffuse light (not including contribution from direct skylight) on the viewing zenith angle (30 degrees, 70 degrees, and 90 degrees), solar zenith angle (23 degrees -72 degrees), depth of 0.5-3 m, and light wavelength (380-650 nm) while observing within the azimuthal plane in the wind-wave direction. Polarization and radiance fluctuated with time. Light variability (presented by the coefficient of variation calculated over a series of fluctuations in the radiance and percent polarization, and by the standard deviation calculated over a series of fluctuations in the e-vector orientation) was highest at a viewing zenith angle of 70 degrees , depended positively on the solar zenith angle, and decreased with depth at viewing zenith angles of 30 degrees and 70 degrees . Additionally, the variability of the percent polarization was significantly higher than that of the radiance. The temporal light fluctuations offer possibilities, such as enhancing the detection of transparent and reflecting objects; however, they set constraints on the optimal underwater polarization vision by both animals and by the use of instruments.     

特高压输变电设备状态监测数据通信仿真研究

针对特高压输变电设备状态监测系统主站转发数据时效性低、负荷重的问题,提出从特高压变电站直接获取输变电设备状态监测数据的获取方式,并利用OPNET建立仿真模型,对比了转发方式与直采方式下,输变电设备状态监测系统主站数据中心服务器与特高压端数据服务器系统负载、CPU使用率、业务处理时间的异同。结果表明,通过直采方式获取特高压变电站设备状态监测数据效率较高,对服务器影响较小。     

Surface-induced dissociation of peptides and protein complexes in a quadrupole/time-of-flight mass spectrometer

A novel in-line surface-induced dissociation (SID) device was designed and implemented in a commercial QTOF instrument (Waters/Micromass QTOF II). This new setup allows efficient SID for a broad range of molecules. It also allows direct comparison with conventional collision-induced dissociation (CID) on the same instrument, taking advantage of the characteristics of QTOF instrumentation, including extended mass range, improved sensitivity, and better resolution compared with quadrupole analyzers and ion traps. Various peptides and a noncovalent protein complex have been electrosprayed and analyzed with the new SID setup. Here we present SID of leucine enkephalin, fibrinopeptide A, melittin, insulin chain-B, and a noncovalent protein complex from wheat, heat shock protein 16.9. The SID spectra were also compared to CID spectra. With the SID setup installed, ion transmission proved to be efficient. SID fragmentation patterns of peptides are, in general, similar to CID, with differences in the relative intensities of some peaks such as immonium ions, backbone cleavage b- versus y-type ions, and y- versus y-NH3 ions, suggesting enhanced accessibility to high-energy/secondary fragmentation channels with SID. Furthermore, these results demonstrate that the in-line SID setup is a valid substitute for CID, with potential advantages for activation of singly/multiply charged peptides and larger species such as noncovalent protein complexes.     

The impact of anthocyanin-rich red raspberry extract (ARRE) on the properties of edible soy protein isolate (SPI) films

To modify the properties of edible soy protein isolate (SPI) films, 0.5% anthocyanin-rich red raspberry (Rubus strigosus) extract (ARRE) (0.5 g raspberry powder in 95% ethyl alcohol/water/85% lactic acid [80:19:1. v/v/v]) was incorporated into film-forming solutions. ARRE resulted in an SPI film having significantly enhanced tensile strength (P < 0.05) and % elongation at break (P < 0.05), as well as increased water swelling ratio (P < 0.05) and in vitro pepsin digestibility (P < 0.05). The resultant films also showed significantly decreased water solubility and water vapor permeability (P < 0.05). In addition, ARRE increased darkness, redness, and yellowness film appearance as evidenced by a lower L* (P < 0.05), greater positive a* (P < 0.05), and a higher b* (P < 0.05) than the control film. Scanning electron microscopy images revealed that extract-added films had denser and more compact cross-section microstructure. Fourier transform infrared spectra illustrated that ARRE-created hydrogen bonding involved conformational changes of soy protein without destroying its backbone structure. SDS-PAGE electrophoretograms revealed that the extract induced intermolecular interaction of the soy protein monomers. Natural plant extracts would be a promising ingredient to make SPI films with different physicochemical properties and applications. PRACTICAL APPLICATION: This study characterizes the potential physicochemical changes of SPI film with incorporated raspberry extract. Upon the above modification, the resultant film was found to enhance the applications of pure SPI film in food packaging. For example, SPI-ARRE film could prolong the usage life of SPI film due to increased strength, or could be useful as a desiccant (drying agent) such as a water-absorbing sheet for preserving dried foods due to its increased hydrophilic surface and water-swelling ratio. SPI-ARRE film could also be alternately used as a food wrap with unique color.     

Effect of retail lights on acceptability of salami

The effects of light source on the acceptability of Hungarian, Hot-Hungarian and regular salamis were investigated. The color of all salamis was most preferred (P<0.05) under incandescent (INC) light, as compared to fluorescent (FL) and metal halide (MH). Higher buying response was also evident when INC was used. The two Hungarian salamis, which had a high red component (higher a* and chroma values), received higher color preference scores under FL compared to MH. Most panelists described the color of the Hungarian salami under INC light as red, but brown under FL and MH. Relative luminance data, collected with a fiber optic probe connected to a photo-diode array, demonstrated the reason to be low red color seen in salamis presented under FL and MH lights.     

Arabidopsis thaliana Plants with Different Levels of Aliphatic- and Indolyl-Glucosinolates Affect Host Selection and Performance of Bemisia tabaci

Generalist insects show reduced selectivity when subjected to similar, but not identical, host plant chemical signatures. Here, we produced transgenic Arabidopsis thaliana plants that over-express genes regulating the aliphatic- and indolyl- glucosinolates biosynthetic pathways with either a constitutive (CaMV 35S) or a phloem-specific promoter (AtSUC2). This allowed us to examine how exposure to high levels of aliphatic- or indolyl-glucosinolates in homogenous habitats (leaf cage apparatus containing two wild-type or two transgenic leaves) and heterogeneous habitats (leaf cage apparatus containing one wild-type and one transgenic leaf) affects host selection and performance of Bemsia tabaci, a generalist phloem-feeding insect. Data from homogenous habitats indicated that exposure to A. thaliana plants accumulating high levels of aliphatic- or indolyl-glucosinolates negatively affected the performance of both adult females and nymphs of B. tabaci. Data from heterogeneous habitats indicated that B. tabaci adult females selected for oviposition plants on which their offspring perform better (preference-performance relationship). However, the combinations of wild-type and transgenic plants in heterogeneous habitats increased the period of time until the first choice was made and led to increased movement rate on transgenic plants, and reduced fecundity on wild-type plants. Overall, our findings are consistent with the view that both performance and selectivity of B. tabaci decrease in heterogeneous habitats that contain plants with closely-related chemical signatures.     

并联电池模块用磁性元件优化设计

为了有效地利用有限的占用蓄电池电能,直流变换模块的电能转换效率成为直流模块认证的关键参数之一。直流模块的能量损耗主要集中在功率开关管、磁性元件、整流管三方面。其中磁性元件的设计方式决定了变换器的转换效率,在提高模块效率方面起着关键作用。本文从磁性器件的几个关键设计点进行分析,实现了变换器的最高电能转换效率。     

A leucine zipper-like sequence from the cytoplasmic tail of the HIV-1 envelope glycoprotein binds and perturbs lipid bilayers

HIV-1 transmembrane envelope glycoprotein (gp41) has an unusually long cytoplasmic domain that has secondary associations with the inner leaflet of the membrane. Two highly amphiphatic alpha-helices in the cytoplasmic domain of gp41 have previously been shown to interact with lipid bilayers. We have detected a highly conserved leucine zipper-like sequence between the two alpha-helices. A peptide corresponding to this segment (residues 789-815, LLP-3) aggregates in aqueous solution, but spontaneously inserts into phospholipid membranes and dissociates into alpha-helical monomers. The peptide perturbs the bilayer structure resulting in the formation of micelles and other non-bilayer structures. Tryptophan fluorescence quenching experiments using brominated phospholipids revealed that the peptide penetrates deeply into the hydrophobic milieu of the membrane bilayer. The peptide interacts equally with zwitterionic and negatively-charged phospholipid membranes and is protected from proteolytic digestion in its membrane-bound state. Polarized attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy showed that the LLP-3 alpha-helix axis is about 70 degrees from the normal to the membrane plane. The ATR-FTIR CH2-stretching dichroic ratio increases when the peptide is incorporated into pure phospholipid membranes, further indicating that the peptide can deeply penetrate and perturb the bilayer structure. Integrating these data with what is already known about the membrane-associating features of adjacent segments, we propose a revised structural model in which a large portion of the cytoplasmic tail of the HIV-1 envelope glycoprotein is associated with the membrane.