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21.
Summary Mono- and diterpenoid components of severalNasutitermitinae soldier secretions have been characterised by gas chromatographymass spectrometry. Patterns in monoterpene distribution are useful, but not sufficient for chemotaxonomic purposes without determination of the diterpene distribution. Diterpenoids are structurally complex and can have tetracyclic, tricyclic and bicyclic skeletal structures with various degrees of oxygenation. The relative retention indices for several identified diterpenoid compounds have been determined on OV-1 and OV-17 columns. The amount and distribution of the terpenoid components are useful aids to chemotaxonomy forNasutitermitinae termites.
Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980. 相似文献
Gaschromatographisch-massenspektrometrische Analyse der Verteidigungs-Sekrete der Termiten-Subfamilie Nasutitermitinae
Zusammenfassung Mono- und Diterpenderivate in den Sekreten verschiedenerNasutitermitinae-Soldaten wurden mit Hilfe der Gaschromatographie-Massenspektro-metrie charakterisiert. Verteilungsmuster der Monoterpene sind nützlich, aber für chemotaxonomische Zwecke ohne Bestimmung der Diterpen-Verteilung nicht ausreichend. Diterpenabkömmlinge sind in struktureller Hinsicht komplex und haben tetracyklische, tricyklische und bicyklische Strukturen mit wechselndem Sauerstoffgehalt. Die relativen Retentionsindices für einzelne identifizierte Diterpenabkömmlinge wurden auf OV-1- und OV-17-Säulen bestimmt. Menge und Verteilung der Terpenabkömmlinge sind nützliche Hilfsmittel für die Chemotaxonomie der genannten Termiten.
Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980. 相似文献
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In the field of reinforcement learning, we propose a Correct Proximal Policy Optimization (CPPO) algorithm based on the modified penalty factor β and relative entropy in order to solve the robustness and stationarity of traditional algorithms. Firstly, In the process of reinforcement learning, this paper establishes a strategy evaluation mechanism through the policy distribution function. Secondly, the state space function is quantified by introducing entropy, whereby the approximation policy is used to approximate the real policy distribution, and the kernel function estimation and calculation of relative entropy is used to fit the reward function based on complex problem. Finally, through the comparative analysis on the classic test cases, we demonstrated that our proposed algorithm is effective, has a faster convergence speed and better performance than the traditional PPO algorithm, and the measure of the relative entropy can show the differences. In addition, it can more efficiently use the information of complex environment to learn policies. At the same time, not only can our paper explain the rationality of the policy distribution theory, the proposed framework can also balance between iteration steps, computational complexity and convergence speed, and we also introduced an effective measure of performance using the relative entropy concept. 相似文献
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Loong C Vashishta P Kalia RK Degani MH Price DL Jorgensen JD Hinks DG Dabrowski B Mitchell AW Richards DR Zheng Y 《Physical review letters》1989,62(22):2628-2631
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The level schemes of75Se and79Kr have been established through gamma ray and conversion electron spectroscopy following75As (p, nγ ?e) and79Br (p, nγe?) reactions. The data on these nuclei and the nuclei in the neighbourhood of this mass region are discussed and evidence is presented to show that the nuclei withN~43 are deformed. 相似文献
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Reiter G Burnham C Homouz D Platzman PM Mayers J Abdul-Redah T Moravsky AP Li JC Loong CK Kolesnikov AI 《Physical review letters》2006,97(24):247801
The momentum distribution of the protons in ice Ih, ice VI, high density amorphous ice, and water in carbon nanotubes has been measured using deep inelastic neutron scattering. We find that at 5 K the kinetic energy of the protons is 35 meV less than that in ice Ih at the same temperature, and the high momentum tail of the distribution, characteristic of the molecular covalent bond, is not present. We observe a phase transition between 230 and 268 K to a phase that does resemble ice Ih. Although there is yet no model for water that explains the low temperature momentum distribution, our data reveal that the protons in the hydrogen bonds are coherently delocalized and that the low temperature phase is a qualitatively new phase of ice. 相似文献
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Qiyao Li Ying Li Tianliang Min Junyi Gong Lili Du David Lee Phillips Junkai Liu Jacky W. Y. Lam Herman H. Y. Sung Ian D. Williams Ryan T. K. Kwok Chun Loong Ho Kai Li Jianguo Wang Ben Zhong Tang 《Angewandte Chemie (International ed. in English)》2020,59(24):9470-9477
Pathogen infections and cancer are two major human health problems. Herein, we report the synthesis of an organic salt photosensitizer (PS), called 4TPA‐BQ, by a one‐step reaction. 4TPA‐BQ presents aggregation‐induced emission features. Owing to the aggregation‐induced reactive oxygen species generated and a sufficiently small ΔEST, 4TPA‐BQ shows a satisfactorily high 1O2 generation efficiency of 97.8 %. In vitro and in vivo experiments confirmed that 4TPA‐BQ exhibited potent photodynamic antibacterial performance against ampicillin‐resistant Escherichia coli with good biocompatibility in a short time (15 minutes). When the incubation duration persisted long enough (12 hours), cancer cells were ablated efficiently, leaving normal cells essentially unaffected. This is the first reported time‐dependent fluorescence‐guided photodynamic therapy in one individual PS, which achieves ordered and multiple targeting simply by varying the external conditions. 4TPA‐BQ reveals new design principles for the implementation of efficient PSs in clinical applications. 相似文献
30.
Kian Hoong Chai Loong Kong Leong David Shan-Hill Wong De-Hao Tsai Sumathi Sethupathi 《中国化学会会志》2020,67(6):998-1008
The present work studied the effect of different carbon dioxide (CO2) adsorbents on Ni-based dual-function materials (DFMs) for the development of carbon capture and on-site utilization in a reactor at isothermal condition. The DFMs containing Ni functioning as a methanation catalyst with various CO2 adsorbents (i.e., CaO, MgO, K2CO3, or Na2CO3) were prepared on γ-Al2O3 through sequential impregnation. The result indicated that Ni-Na2CO3/γ-Al2O3 had the highest methanation capacity (i.e., 0.1783 mmol/g) and efficiency (i.e., 71.09%) in the CO2 adsorption–methanation test. The CO2 uptake and the subsequent methanation capacity of the Ni-Na2CO3/γ-Al2O3 increased to more than 24 times and more than 17 times, respectively, compared to Ni/γ-Al2O3. The high methanation capacity was correlated to its highest amount of weak basic sites, substantial CO2 capture capacity and capture/release efficiency, and reactivity to H2 at a lower temperature, supported by CO2-TPD, TGA analyses for adsorption or adsorption–desorption at the isothermal condition, and H2-TPRea, respectively. A continuous cyclic CO2 adsorption–methanation was performed by using the Ni-Na2CO3/γ-Al2O3 and Ni-CaO/γ-Al2O3, showing that the CO2 adsorption capacity was stabilized from third cycle onward, whereas the methanation capacity was stabilized at all cycles, indicating the high stability of the DFMs for both CO2 adsorption and subsequent methanation. This work demonstrated successful synthesis of the Ni-based, low-cost, and stable DFMs with the ability to produce methane via the direct capture of CO2. 相似文献