辐射叶加载的短波宽带鞭状天线优化设计

提出一款具有多层辐射叶结构的新型鞭状天线,在10 m鞭状天线体上设置不同的辐射叶层数、半径、长度、分支数、仰角及其分布情况,研究其对天线辐射性能的影响,综合考虑选择一套最合适的辐射叶结构,并为天线进行双加载和宽带匹配网络的算法优化。仿真结果表明,与现有的普通宽带鞭状天线相比,增益和效率得到了普遍提高,在低频段增益最高提高了3 dB,效率最高提高了5%;在高频段增益最高提高了5 dB,效率最高提高了35%,方向图上翘也得到了一定的抑制,为改善现有的宽带鞭状天线提供一种新的结构设计方法。

Effect of Radiative Forcing on Growth and Photosynthetic Responses of Elaeocarpus glabripetalus Merr.

[Objective] This study aimed to reveal the impact of radiative forcing on the woody plants in subtropical regions of China through the study on the effect of radiative forcing on growth and photosynthetic responses of Elaecarpus glabripetalus Merr. seedlings. [Method] Three gradients of radiative forcing treatments were applied to the species namely, control group （100% natural light）, weak radiative forcing group （39% natural light） and strong radiative forcing group （16% natural light）. The relative contents of chlorophyll, photosynthetic parameters of E. glabripetalus in different periods were measured to analyze the effects of different gradients of radiative forcing on plant height, ground diameter, chlorophyll content, gas exchange parameters, light response cure parameters. [Result] The increased ground diameter of E. glabripetalus in different treatments was the control weak radiative forcing group strong radiative forcing group; the increased plant height in the early period was strong radiative forcing group weak radiative forcing group control, but there was no significant difference during the late period; the relative content of chlorophyll was strong radiative forcing group weak radiative forcing group control. The light compensation point （LCP）, light saturation point （LSP） and the maximum net photosynthetic rate （A max ） were reduced in radiative forcing treatments. The stomatal conductance （G s ）, transpiration rate （Tr） of E. glabripetalus in strong radiative forcing group were significantly smaller than that in the control group, while there was no significant change in dark respiration rate （R d ） and apparent quantum yield （AQY）. [Conclusion] In summary, the radiative forcing can change the environmental factors which have significant effect on the ground diameter, plant height, relative content of chlorophyll and photosynthetic physiological parameters, but with the processing of treatment the effects on ground diameter and plant height increase are not significant in the late period, indicating that E. glabripetalus seedlings have some resistance and adaptability to the radiative forcing environment.

Marine Green Algae as a Supplement for Chlorophyll and Other Nutrients in Vigna Radiata under UV-C Radiation-Induced Stress

The potential protective effect of marine green algae （Codium iyengerii） was examined in UV-C treated seedlings of Vigna radiata. The study comprises of three treatments of UV-C radiation （100-290 nm） dose for one min in alternative days. This results in deformed morphological parameters, including： decrease in plant height, fresh mass of leaves, shoots and roots, as well as leaf areas, which may be attributed with decreased in the relative growth rate, carbohydrate, amino acids, and protein contents of plant. A drastic effect of UV-C radiation was found on the photosynthetic apparatus where increase in red pigmentations on the leaves surface indicates the presence of UV-C absorbing pigments instead of chloroplast pigments. Visible spectrum of leaves chlorophyll showed reduced concentration of visible absorbing pigments which showed the deleterious effect of these radiations on physiological processes of seedlings. These negative effects of UV-C radiation on plant growth were found to be decreased by the application of green seaweed （Codium iyengerii）, and absorption spectrums of chloroplast contents showed that UV-C radiation inducing damages were appropriately managed by enhanced concentration of seaweeds which significantly increased morphological and physiological parameters like leaf, stem, root biomass, and plant height under UV-C radiation were observed.

Estimation of the Land Surface Emissivity in the Hinterland of Taklimakan Desert

An accurate accounting of land surface emissivity(ε) is important both for the retrieval of surface temperatures and the calculation of the longwave surface energy budgets.Since ε is one of the important parameterizations in land surface models(LSMs),accurate accounting also improves the accuracy of surface temperatures and sensible heat fluxes simulated by LSMs.In order to obtain an accurate emissivity,this paper focuses on estimating ε from data collected in the hinterland of Taklimakan Desert by two different methods.In the first method,ε was derived from the surface broadband emissivity in the 8–14 μm thermal infrared atmospheric window,which was determined from spectral radiances observed by field measurements using a portable Fourier transform infrared spectrometer,the mean ε being 0.9051.The second method compared the observed and calculated heat fluxes under nearneutral atmospheric stability and estimated ε indirectly by minimizing the root-mean-square difference between them.The result of the second method found a mean value of 0.9042,which is consistent with the result by the first method.Although the two methods recover ε from different field experiments and data,the difference of meanvalues is 0.0009.The first method is superior to the indirect method,and is also more convenient.

Radioprotective Effect of Lyophyllum Decastes and the Effect on Immunological Functions in Irradiated Mice

In this study, to explore the radiation protection effects of Lyophyllum Decastes Sing （LDS）, a hot distilled-water extract of LDS was orally administered at a dosage of 250mg/kg every other day for a period of 2 weeks in irradiated mice. An automatic blood cell counter was used to measure white blood cells （lymphocytes, monocyte, and granulocytes） one day before X-ray irradiation, and 3 hours, 12 hours, 24 hours, 3 days, 7 days, 15 days and 30 days after irradiation. The Dunnett test was used to examine statistical significance of differences. The peripheral blood cell counts in the Lyophyllum-administered non-irradiation group revealed an increase in the numbers of ieukocytes, lymphocytes and monocytes. For 2 Gy whole body radiation, a significant statistical difference was found between the X-ray group and the Lyophyllum plus X-ray group in the numbers of leukocytes, lymphocytes and monocytes. The results suggest that Lyophyllum restrains blood cell-count falling after irradiation, which is probably mediated at least in part by hemopoietic function, and NK and LAK activities seems to play a role in preventing secondary irffections associated with irradiation.

Daily Variability of Radon Gas in Brazilian Tropics Near Ground Level Surface

By monitoring the ionizing radiation from minute to minute in S^o Jos6 dos Campos, SP, Brazil （230 S, 450 W） using Geiger counter, during January to August 2015, it has confirmed the presence of radon gas in these measures. The observation confirms the existence of a periodicity of 24 hours through the technique （Fast Fourier Transform） applied to the data set, and this cycle can be better visible in longer dry periods. On rainy days or with heavy fog in the region, this periodicity is modified or even disappears. As Geiger do not detect alpha particles due to absorption in the walls of the sensor tube, it measured X and gamma rays coming from the radon gas progeny. Radon gas （222Rn） has a half-life of 19.7 minutes to decays in 214Bi emitting gamma ray energy （45%） with 0.609 MeV which is monitored daily by Geiger. Also 222Rn decays in 26.8 minutes in 214pb giving （37%） with 0.35 MeV and others with less energy. It is confirmed the good performance ofa Geiger tube with LND 712 working with about 500 VDC rated voltage.

Fatty Acid Composition Analyses of the DCMU Resistant Mutants of Nannochloropsis oculata(Eustigmatophyceae)

Ultraviolet mutagenesis was applied to Nannochloropsis oculata and three mutants resistant to 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) were isolated. The cellular chlorophyll a and total lipid content of the wild are higher in the medium supplemented with DCMU than in the control without DCMU. Without DCMU, the growth rates and chlorophyll a contents of the mutants are similar to those of the wild. Significant changes of fatty acid content and composition have occurred in DCMU-resistant mutants growing in the medium supplemented with DCMU. The total lipid, palmitic acid (16∶0), palmitoleic acid (16∶1ω9) and oleic (18∶1ω9) contents decrease significantly, while the vaccenic acid (18∶1ω11) increases significantly and the EPA content of dried powder increases slightly in the mutants. The study may provide a basis to improve EPA content in Nannochloropsis oculata in the future.

Microwave radiation one-pot synthesis of chloropropyl-functionalized mesoporous MCM-41

Chloropropyl-functionalized mesoporous MCM-41（MCM-41-（CH2）3Cl） was synthesized in alkaline medium by the microwave radiation one-pot method, using cetyltrimethy-lammoniumbromide （CTAB） as novel template, tetraethoxysilane （TEOS） as silica source, and chloropropyltriethoxysilane （C1PTES） as the coupling agent. The microstructure of MCM-41-（CH2）3Cl was characterized by the means of X-ray diffraction （XRD）, nitrogen absorption-desorption, Fourier transform infrared spectroscopy （FT-IR）, scanning electron microscopy （SEM）, and transmission electron microscopy （TEM）. The results show that a successful synthesis of MCM-41-（CH2）3Cl with well structure is obtained. The optimal microwave power is 120 W and the best microwave time is 50 rain. The dosage of chloropropyltriethoxysilane on the structure of chloropropyl-functionalzed MCM-41 was also investigated. It is found that the chloropropyltriethoxysilane volume between 0.8 mL and 1.6 mL is favorable for the formation of highly ordered MCM-41-（CH2）3Cl mesostructure.

车道沟10号

1无线电通信技术发明之后,首先就被应用于战争。军舰、港口之间,陆军野战兵团相互联系都应用了无线电。但号称"陆战之王"的坦克却是应用无线电最晚的。在无线电通信设备正式装备坦克之前,坦克是靠什么相互联系的呢?A.旗语B.传声筒C.

Assessment and analysis of microwave emissivity and transmissivity of a deciduous forest towards the estimate of vegetation biomass

Forests play an important role in the global carbon cycle and have a potential impact on global climatic change.Monitoring forest biomass is of considerable importance in understanding the hydrological cycle.Because of the problem of dense forest cover,no reliable method with which to retrieve soil moisture in forest areas from the microwave emission signature has been established.All of these issues relate to the microwave emissivity and transmissivity characteristics of a forest.The microwave emission contribution received by a sensor above a forest canopy comes from both the soil surface and the vegetation layer.To analyze the relationship of forest biomass and forest emission and transmissivity,a high-order emission model,the matrix-doubling model,which consists of both soil and vegetation models,was developed and then validated for a young deciduous forest stand in a field experiment.To simulate the emissivity and transmissivity of a deciduous forest in the L and X bands using the matrix-doubling model,the parameters of components of deciduous trees when the leaf area index varies from 1 to10 were generated by an L-system and a forest growth model.The emissivity and transmissivity of a forest and the relationships of these parameters to forest biomass are presented and analyzed in this paper.Emissivity in the L band when the leaf area index is less than 6 and at viewing angles less than 40°,and transmissivity in the L band are the most sensitive parameters in deciduous forest biomass estimation.