00 g干重之间;主要成分反式茴香脑的相对含量

d Component of Fennel from Seven Different AreasREN An-xiang~1,HE Jin-ming~1,GUO Yuan~2,WANG Yu-mei~(1,2)(1.College of Yingdong Bioengineer Shaoguan University,Shaoguan,Guangdong 512005,China;2.Agriculture College of Inner Mongolia Agricul愎?对科技型中小企业无形资产价值的评估提出了展望。     

Influence of nickel addition on the microstructure and mechanical properties of Al2O3-5vol%ZrO2 ceramic composites prepared via precipitation method

The aim of this work was to investigate the microstructure and mechanical properties of 1vol%-Ni-added yttria-stabilized zirconia (YSZ) toughened alumina composites. First, Ni powders were heterogeneously precipitated in an alumina-zirconia powder mixture suspended in water; the prepared specimens were then pressureless sintered at 1550℃/2 h in a 90vol%Ar/10vol% H₂ atmosphere. The structure of phases and microstructure of the composites were characterized by X-ray diffraction and scanning electron microscopy, respectively. Mechanical characterization of the specimens was carried out through Vickers hardness, Vickers indentation toughness, and three-point flexural bending tests. The fine Ni particles were homogeneously dispersed throughout the alumina matrix because of the employed processing method. Furthermore, hardness and toughness values were found to increase by 8% and 50%, respectively, with Ni addition, whereas the relative densities and flexural strength values were found to remain unchanged.     

Electrodeposition of Al from a 1-butylpyrrolidine-AlCl3 ionic liquid

The addition of 1-butylpyrrolidine to AlCl_3 results in the formation of an electrolyte that is suited to Al deposition.The feasibility of electrodepositing Al from the synthesized electrolyte was investigated.Several compositions of AlCl_3 and 1-butylpyrrolidine were prepared for this purpose.These mixtures show a different phase behavior at various compositions of AlCl_3 and 1-butylpyrrolidine.IR,Raman and NMR spectroscopy were employed to characterize the synthesized liquids.Among the prepared compositions,1:1.2 mol ratio of 1-butylpyrrolidine:AlCl_3 and the upper phase of 1:1.3 mol ratio of 1-butylpyrrolidine:AlCl_3 were found to be suitable for Al electrodeposition at room temperature(RT).Uniform and thick( mm thick) layers of Al were obtained on copper at RT.Al deposition occured from the cationic species of AlCl_3 xLty(where x r 2,y ? 1–2,and L ? 1-butylpyrrolidine) in this electrolyte.This behavior is contrary to the well investigated classic AlCl_3 based ionic liquids,where the deposition of Al occurs mainly from anionic Al2 Cl 7ions.     

Influence of the iodide/iodine redox system on the self-discharge of AC/AC electrochemical capacitors in salt aqueous electrolyte

Self-discharge(SD) of AC/AC(AC ? activated carbon) electrochemical capacitors in aqueous solutions of lithium sulfate(Li2SO4) and lithium sulfate t iodide salts(Li2SO4tKI or Li2SO4tLi I) was investigated at 24 1C and 40 1C after cell potential hold at values from 1 V to 1.6 V.At24 1C,the cells exhibit lower SD in Li2SO4tKI than in Li2SO4,owing to the redox activity of the 2I /I2 system which drives the positive AC electrode to operate in narrow potential range and display lower potential drop than in Li2SO4.At 401 C,the capacitors exhibit comparable and reduced SD both in Li2SO4tLi I and Li2SO4,whatever the holding cell potential.Three-electrode cell experiments demonstrate that,at 40 1C,hydrogen chemisorption is thermodynamically unfavored under negative polarization,while the activity of the 2I /I2 redox system under positive polarization is only slightly reduced.As a consequence,the AC/AC cells in Li2SO4 exhibit a typical electrical double-layer performance at 401 C,whereas they still behave as hybrid ones in Li2SO4tLi I,with twice higher capacitance than in Li2SO4.The(Ui-Ut) vs t1/2plots demonstrate that SD is essentially controlled by diffusion at 401 C,suggesting that it originates from bulkier hydrated ions.Overall,in the investigated temperature range,the AC/AC capacitors in Li2SO4tLi I demonstrate low self-discharge and high capacitance,while being able to operate up to 1.6 V.     

Influence factor of diesel soot formation in diesel engine combustion predicted by multistep soot model with highlight in soot surface activity

As more strict regulations on soot emission with increasing emphasis on the emitted soot particle size have been imposed, diesel engine partially premixed combustion had been proven to achieve ultra-low NOx and soot emissions with high thermal efficiency simulta- neously, by synergy control of mixing and chemical parameters. It calls for further study in the effect of com- bustion boundaries on soot formation. In this study, soot formation characteristic was investigated by CFD code coupled with reduced n-heptane model and improved multistep soot model. History of acetylene, which is taken as the main species of PAH formation and soot surface growth, plays more important roles on soot prediction. The revised parameter of fraction of active sites αCH was introduced as the indicator of soot surface activity in diesel soot formation. The effects of combustion boundaries on soot surface activity and soot surface growth were explored in this study. When the mixture was quite homogeneous, lowered combustion temperature was the main factor for reduced soot formation due to the lowered specific surface growth rate RCH, in spite of ec/4 increasing slightly due to the slowed decay rate of surface activity. As the inhomo- geneity of the mixture was increased, more unburned hydrocarbons were produced, promoting the formation of acetylene and soot surface activity. It was the dominated reason for higher soot surface growth rate, resulted wors- ened engine-out soot. In addition, residual of CO in later combustion phase impeded the re-oxidation of soot.     

Genome-wide analysis of nucleotide-binding site disease resistance genes in Medicago truncatula

The class of nucleotide-binding site （NBS）- Leucine-rich repeat （LRR） disease resistance genes play an important role in defending plants from a variety of pathogens and insect pests. Consequently, many NBS-LRR genes have been identified in various plant species. In this study, we identified 617 NBS-encoding genes in the Medicago truncatula genome （Mt3.5v5） and divided them into two groups, regular （490） and non-regular （127） NBS- LRR genes. The regular NBS-LRR genes were character- ized on the bases of structural diversity, chromosomal location, gene duplication, conserved protein motifs, and EST expression profiling. According to N-terminal motifs and LRR motifs, the 490 regular NBS-LRR genes were then classified into 10 types： CC-NBS （4）, CC-NBS-LRR （212）, TIR-NBS （20）, TIR-NBS-LRR （160）, TIR-NBS-TIR （1）, TIR-NBS-TIR-LRR （2）, NBS-TIR （7）, NBS-TIR-LRR （1）, NBS （10）, and NBS-LRR （73）. Analysis of the phys- ical location and duplications of the regular NBS-LRR genes revealed that the M. truncatula genome is similar to rice. Interestingly, we found that TIR-type genes are more frequently expressed than non-TIR-type genes in M. trun- catula, whereas the number of non-TIR-type regular NBS- LRR genes was greater than TIR-type genes, suggesting the gene expression was not associated with the total number of NBS-LRR genes. Moreover, we found that the phylogenetic tree supported our division of the regular NBS-LRR genes into two distinct clades （TIR-type and non-TIR-type）, but some of the non-TIR-type lineages contain TIR-type genes. These analyses provide a robust database of NBS-LRR genes in M. truncatula that will facilitate the isolation of new resistance genes and breeding strategies to engineer disease resistance in leguminous crop     

An optimized short-term wind power interval prediction method considering NWP accuracy

In recent years, the accuracy of the wind power prediction has been urgently studied and improved to satisfy the requirements of power system operation. In this paper, the relevance vector machine(RVM)-based models are established to predict the wind power and its interval for a given confidence level. An NWP improvement module is presented considering the characteristic of NWP error. Moreover, two parameter optimization algorithms are applied to further improve the prediction model and to compare each performance. To take three wind farms in China as examples, the performance of two RVM-based models optimized, respectively, by genetic algorithm(GA)and particle swarm optimization(PSO) are compared with predictions based on a genetic algorithm–artificial neural network(GA–ANN) and support vector machine. Results show that the proposed models have better prediction accuracy with GA–RVM model and more efficient calculation with PSO–RVM.     

Validation of AMSU-A measurements from two different calibrations in the lower stratosphere using COSMIC radio occultation data

GPS radio occultation data from the Constellation Observing System for Meteorology, Ionosphere, and Climate(COSMIC) mission were used to validate the measurements of the advanced microwave sounding unit-A(AMSU-A) in the lower stratosphere from different satellites. AMSU-A observations from two different calibrations—the pre-launch operational and post-launch simultaneous nadir overpass(SNO) calibrations—were compared to microwave brightness temperatures(Tb)simulated from COSMIC data. Observations from three satellites(NOAA-15,-16, and-18) were used in the comparison. The results showed that AMSU-A Tb measurements from both calibrations and from all three NOAA satellites were underestimated in the lower stratosphere,and that the biases were larger in polar winters, especially over the southern high latitudes. In comparison to operational calibration, the SNO-calibrated AMSU-A data produced much smaller biases relative to the COSMIC data.The improvement due to SNO calibration was quantified by a Ratio index, which measured the bias changes from operational to SNO calibrations relative to the biases between the operational-calibrated AMSU-A data and the COSMIC data. The Ratio values were 70 % for NOAA-15and [80 % for NOAA-18 and-16, indicating that the SNO calibration method significantly reduced AMSU-A biases and effectively improved AMSU-A data quality.     

库贾的抉择——小兴安岭东北虎种群的恢复及展望

我国的小兴安岭自古以来就是东北虎的出没之地,但是近40年来一直没有东北虎的踪迹.值得欣慰的是,自2014年以来,随着东北地区林地的恢复和森林植被范围的扩大,逐渐有一些东北虎个体从俄罗斯来到我国境内.它们来寻找什么?能不能长久地留在我们的森林中呢?     

燃 烧的星球

正火光——野外的和化石燃料的火光——照亮了地球。是时候宣布人类已经创造了一个火新世(Pyrocene)了吗?从北极到亚马逊,从加利福尼亚到大卡纳利群岛,从婆罗洲到印度,从安哥拉到澳大利亚——大火似乎无处不在。大火产生的烟雾在次大陆遮天蔽日;火光在夜晚像银河系的星星一样照亮了各个大陆。人们可能会问:还有哪里没烧起来?在一些看不到火焰的地方,是城市的灯光——煤和石油的燃烧转化为电力。在许多观察家看来,它们似乎是即将到来的世界末日的前兆。就连格陵兰岛也在燃烧。