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991.
Volatile organic compounds in honey are known for their considerable impact on the organoleptic properties of honey, such as aroma, flavor, taste, and texture. The type and composition of volatile organic compounds are influenced by entomological, geographical, and botanical origins; thus, these compounds have the potential to be chemical markers. Sixty-two volatile compounds were identified using gas chromatography–mass spectrometry from 30 Heterotrigona itama (H. itama) honey samples from 3 different geographical origins. Hydrocarbons and benzene derivatives were the dominant classes of volatile organic compounds in the samples. Both clustering and discriminant analyses demonstrated a clear separation between samples from distant origins (Kedah and Perak), and the volcano plot supported it. The reliability and predictability of the partial least squares–discriminant analysis model from the discriminant analysis were validated using cross-validation (R2: 0.93; Q2: 0.83; accuracy: 0.97) and the permutation test (p < 0.001), and the output depicted that the model is legitimate. In combination with the variable importance of projection (VIP > 1.0) and the Kruskal–Wallis test (p < 0.01), 19 volatile organic compounds (encompassed aldehydes, benzene derivatives, esters, hydrocarbons, and terpenoids) were sorted and named potent chemical markers in classifying honey samples from three geographical origins. In brief, this study illustrated that volatile organic compounds of stingless honey originated from the same bee species, but different geographical origins could be applied as chemical markers. 相似文献
992.
This study explores how organizational management can promote employee voice behaviours, as positive behavioural reactions with constructive ideas, in responding to organizational crisis. Using an experimental study (N = 640) among full‐time employees in the United States, the study found that pre‐crisis internal reputation and crisis communication strategies—accommodative response and stealing thunder—positively and directly affected constructive employee voice behaviours in a crisis situation. Furthermore, the study revealed how post‐crisis internal reputation mediates the influences of pre‐crisis internal reputation and stealing thunder on positive/constructive and negative/destructive employee voice behaviours. The findings of this study contribute to the theoretical development of crisis communication in the internal context of an organization, especially with respect to employee voice behaviours. The study also highlights an important practical implication for crisis managers who can activate and promote positive employee behaviour voices, thereby influencing leadership's strategic decision‐making in an organizational crisis. 相似文献
993.
Improving the bit error rate (BER) performance at low elevation angles is a crucial determining factor for the capacity of any low earth orbit (LEO) satellite system. In previous work, it has been demonstrated that the BER performance of a DS/CDMA-based equatorial LEO satellite system on a downlink can be improved significantly by using satellite diversity. The authors address the issue of improving BER at low elevation angles by using turbo codes 相似文献
994.
Complete benzene oxidation over Pt-Pd bimetal catalyst supported on γ-alumina: influence of Pt-Pd ratio on the catalytic activity 总被引:1,自引:0,他引:1
Hyoung Sik Kim Tae Won Kim Hyoung Lim Koh Seo Ho Lee Byoung Ryul Min 《Applied Catalysis A: General》2005,280(2):125-131
Pt-Pd bimetal catalysts were prepared in order to develop and investigate catalysts with excellent activity and stability for benzene destruction. In the reaction results, the addition of Pt to Pd/γ-Al2O3 catalyst brought about the increase of catalytic activity. Moreover, it was effective in preventing the deactivation of the catalysts in benzene combustion. The addition of some amount of Pt made Pd particles available for better benzene combustion. On the contrary, the addition of Pt beyond a certain amount decreases activity because of the Pd active sites overlapped with the Pt active sites. The activity of the catalysts is related to oxidation state of metal, Pd/Al ratio and particle size on γ-Al2O3. These effects of Pt addition to Pd catalysts were studied by XPS, XRD, and TEM analyses. 相似文献
995.
L. A. P. Freitas O. M. Dogan C. J. Lim J. R. Grace B. Luo 《Chemical Engineering Communications》2000,181(1):243-258
Tests were carried out with rectangular spouted bed columns of different thickness, i.e., front-to-back dimension, while holding the column width and air-entry slot width constant, to investigate the effects on spoul stability and bed hydrodynamics. For the three sizes of glass beads and one size of polyethylene beads examined, increasing the column thickness led to three-dimensional effects, such as formation of multiple spouts, and affected such hydrodynamics variables as the minimum spouting velocity, maximum spoutable bed depth and maximum pressure drop. 相似文献
996.
TixSi1xOy (TSO) thin films are fabricated using plasma‐enhanced atomic layer deposition. The Ti content in the TSO films is controlled by adjusting the sub‐cycle ratio of TiO2 and SiO2. The refractive indices of SiO2 and TiO2 are 1.4 and 2.4, respectively. Hence, tailoring of the refractivity indices from 1.4 to 2.4 is feasible. The controllability of the refractive index and film thickness enables application of an antireflection coating layer to TSO films for use as a thin film solar cell. The TSO coating layer on an Si wafer dramatically reduces reflectivity compared to a bare Si wafer. In the measurement of the current‐voltage characteristics, a nonlinear coefficient of 13.6 is obtained in the TSO films. 相似文献
997.
Jae-Shin Lee Min-Sun Keel Shin-Il Lim Suki Kim 《Electronics letters》2000,36(23):1907-1908
Conventional CMOS charge pump circuits have some current mismatching characteristics. The current mismatch of the charge pump in the PLLs generates a phase offset, which increases spurs in the PLL output signals. In particular, it reduces the locking range in wide range PLLs with a dual loop scheme. A new charge pump circuit with perfect current matching characteristics is proposed. By using an error amplifier and reference current sources, one can achieve a charge pump with good current matching characteristics. It shows nearly perfect current matching characteristics over the whole VCO input range, and the amount of the reference spur is <-75 dBc in the PLL output signal. The charge pump circuit is implemented in a 0.25 μm CMOS process 相似文献
998.
Sae Bom Lim Jagan Mohan Rao Tingirikari Ji Sun Seo Ling Li Sangmin Shim Jin-Ho Seo Nam Soo Han 《Food science and biotechnology》2018,27(1):73-78
Lactic acid bacteria (LAB) are key for the fermentation of sourdoughs to improve the quality and nutritive value of bread. The aim of this study was to isolate the LAB starter for sourdough fermentation from Jeung-pyun, a Korean traditional rice cake. Among the twenty two LAB screened, five isolates were selected based on exo-polysaccharide production. Among them, three isolates showed cell growth greater than 8.5 Log CFU/g, maximum increase in the volume of dough, and dextran concentration up to 0.16%. During the sourdough fermentation, pH and total titratable acidity (TTA) were changed, as the three isolates synthesized lactic acid and acetic acid with fermentation quotients less than 2.0. They were identified as Leuconostoc lactis EFEL005, Lactobacillus brevis EFEL004, and Le. citreum EFEL006. They displayed good fermentation properties (growth, dextran production, pH, and TTA) in dough and they are regarded as potential starters to be used in sourdough fermentation. 相似文献
999.
The LixNi0.23Co0.12Mn0.65O2 electrode system with various compositions (x = 1.19, 1.33, 1.46, 1.58) was synthesized from a metal oxide precursor synthesized by co-precipitation method. The XRD patterns of the prepared powders revealed a hexagonal α-NaFeO2 structure (space group: R-3m, 166) and the existence of a Li2MnO3 phase in the composite structure. In particular, the low Li content sample shows a three integrated structure (spinel, Li2MnO3, LiMO2) for a Li/Metal(Ni/Co/Mn) mol ratio of 1.2. Scanning electron microscopy showed that all the synthesized samples contained spherical agglomerates with a size of 8–10 μm. Among the samples tested, Li1.46Ni0.23Co0.12Mn0.65O2 shows relatively high charge and discharge capacity for the first cycle is 287, 192.9 mA h g?1, respectively. Also, charge transfer resistance was also significantly improved compare with other samples. 相似文献
1000.
Relative dissociation energies (RDEs) are obtained for the major fragment ions produced by electrospray ionization/surface-induced dissociation of singly protonated triglycine, tetraglycine, leucine enkephalin, and leucine enkephalin arginine. A previously described data analysis method (Lim, H.; et al. J. Phys. Chem. B 1998, 102, 4753) is employed to analyze the energy-resolved mass spectra by subtracting out the distribution of energy transferred to the surface, integrating over the distribution of the incident ion energy, and taking into account the precursor ion initial internal energy and kinetic energy distributions. These variables are optimized by anchoring the RDE for the lowest energy fragment of a given precursor ion to its literature values and then using these optimized parameters to obtain the other RDEs. The RDEs of the four major fragments of triglycine vary from 2.4 eV for the b(2) fragment ion to 6.0 eV for the a(2) ion. The RDEs of the four major fragments of tetraglycine vary from 3.2 eV for the y(2) ion to 5.7 eV for the a(2) ion. The leucine enkephalin RDEs range from 1.1 eV for the b(4) ion to 2.1 eV for the b(2) ion. The leucine enkephalin arginine RDEs all lay between 2.5 and 3.5 eV. The overall trend of fragmentation order for all peptides is (y(n), b(n)) < a(n) and is consistent with the results from other experiments. The peptide RDEs presented here are only as accurate as the literature values to which they are anchored. Determination of absolute dissociation energies from SID data will require further refinement of the data analysis method. 相似文献