探月三期月地高速再入返回飞行器工程参数测量系统设计及飞行结果

月地高速再入返回飞行试验任务目标是验证与半弹道跳跃式返回再入的相关技术,全面可靠的获取试验相关数据,对试验结果评估至关重要,为此飞行器专门设计实现了一套包括力、热、图像等参数采集与存储的工程参数测量系统,本文给出了该系统的设计情况及飞行结果.     

甲醇中29种VOCs混合标准样品短期稳定性研究

为考察运输过程中环境温度的变化对挥发性有机物（VOCs）混合标准样品量值产生的影响,模拟极端运输条件(-40 ℃、4 ℃、室温、55 ℃),采用经典和同步两种稳定性研究方案考察甲醇中29种VOCs混合标准样品的短期稳定性。结果表明：同步稳定性研究方案因一次校准进行所有测量降低了不确定度,更适合对多组分挥发性有机物进行稳定性评价;在-40 ℃下所研究标准样品所有组分量值稳定, 4 ℃与室温冷藏保存两周期间,标准样品量值稳定,而在55 ℃保存条件下,组分环氧氯丙烷的浓度有明显下降趋势;由于环氧氯丙烷的浓度受温度影响较大,甲醇中29种VOCs混合标准样品在运输过程中需采用低温条件,若长期保存,应尽快转移至冷冻环境中防止环氧氯丙烷分解。     

Synthesis, structure, optoelectronic properties of novel zinc Schiff-base complexes

Two novel zinc Schiff-base complexes, bis-(N-(2-hydroxybenzidene)-p-aminodimethylaniline)zinc(II) (2) and bis-(N-(2-hydroxy-1-naphthidene)-p-aminodimethylaniline)zinc(II) (4) were designed and synthesized. Both the complexes exhibit good solubility in organic solvents and excellent thermal stabilities. A single crystal of 2 was grown and its crystalline structure was determined from X-ray diffraction data. Analysis of the electronic structures of both the zinc complexes calculated by density functional theory reveals a localization of orbital. The UV-Vis absorption and photoluminescence profiles of 4 in thin film are similar to those of 2, but the emission for 4 is red-shifted compared to 2. Three-layered devices with a configuration of ITO/NPB/2/Alq 3 /LiF/Al and ITO/NPB/4/Alq 3 /LiF/Al show a yellow and red emission, respectively.     

75 mW robust single frequency Yb-doped DFB fiber Bragg grating laser

Incorporating the shielded method and post-processing method, a 75 mW single frequency Yb-doped DFB fiber laser was obtained with a 250 mW laser diode pump source at 978 nm. The threshold of the laser is 2 mW. The laser is single-polarization operation and the output power fluctuation is less than 0.2 mW in one hour when the pump power is 250 mW.     

Pollen indicators of human activity

The study of past human activities and their environmental effect is high in the agenda of global change research. A record of pollen assemblages is one of the most common proxies employed for detecting the impact of human activities on the landscape. In this review, we provide a summary and discussion on the recent progress on the use of pollen as indicators of human activity. For most of the studies related to human impact, the following features have been focused on： （1） decline of certain tree pollen; （2） flourishing of pioneer plant pollen; （3） concomitant occurrence of cereal-type pollen and cropland weed pollen; （4） abrupt changes in pollen concentration and richness; and （5） occurrence of nitrophi- Ious plants and pastoral weed. Pollen of anthropogenic plants （weeds and cereal-type plants） is ideal indicators of human activities. Different types of human activities will result in different pollen assem- blages. Patterns of human-impacted pollen spectra would vary between forested areas and grassland. In the study of human impact with pollen data, high resolution in both time and space must be consid- ered. High resolution in space will help to inform the complexity of the landscape. More importantly, it can help to reveal the interference of human activities on the landscape, hence avoiding the bias created by the limited data points. Fine resolution in time will make accurate recording of short-lived events possible, hence avoiding the exclusion of events related to human activities. The combination of palynology with other proxies will help to decipher more accurately landscape changes through time. Charcoal is a particularly useful proxy for recording the disturbance of humans on vegetation. Its peak values usually occur with pronounced drop of tree pollen and significant rise of anthropogenic pollen.     

Structural origin of sexual dichromatic coloration and luster in the beetle Goliathus cacicus

In the beetle Goliathus cacicus, male elytra show silky luster with iridescence while female ones appear lusterless white without iridescence to our perception. We revealed by structural characterizations and optical measurements that elytral coloration and luster of both male and female beetles stem from the tubular scales on the elytra, whose interior is filled with a random structure. Distinct differences between male and female scales reside in the cortex thickness and the filling fraction of the random structure, which are important factors in the determination of the sexual dichromatic luster and iridescence. In additional to reflection peaks in the visible range, spectral measurements indicate that both male and female elytra display also strong iridescent ultraviolet (UV) reflections. Scattering spectra show that both male and female elytra display UV luster, although it is absent for female ones in the visible range.     

喷粉处理改善孕育效果的试验研究

喷粉孕育是将粉粒状孕育剂以氮气为载体喷入铁水的一种新型工艺方法．本文采用自制的喷粉装置进行了喷粉孕育的试验研究．结果表明：喷粉处理可改善孕育效果，改善石墨形态，明显地细化共晶团，有效地消除白口倾向，从而提高铸铁的强度．喷粉孕育成为一种极有效的孕育技术．     

近视灵口服液中决明子的TLC鉴别

近视灵口服液由决明子等12味药材组成。试验确定了其主药决明子的薄层层析鉴别方法，对于含决明于复方中药制剂及相关食品的质量控制具有实用价值。     

Enhancement of transfection efficiency for HeLa cells via incorporating arsinine moiety into chitosan

Arginine-rich peptides have attracted considerable attention due to their distinct internalization mechanism. It was reported that arginine and guanidino moieties were able to translocate through cell membranes and played a critical role in the process of membrane permeation. In this work, arginine was conjugated to the backbone of chitosan to form a novel chitosan derivative, arginine modified chitosan （Arg-CS）. Arg-CS/DNA complexes were prepared according to the method of coacervation process. The physicochemical properties of Arg-CS and Arg-CS/DNA complexes were characterized and the transfection activity and efficiency mediated by Arg-CS/DNA complexes were investigated taking HeLa cells as target cells. Arg-CS was characterized by FTIR and ^13C NMR. Arg-CS/DNA polyelectrolyte complexes were investigated by agarose gel retardation, dynamic light scattering （DLS） and atomic force microscopy （AFM）. The results revealed that the Arg-CS/DNA complexes started to form at N/P ratio of 2：1, and the size of particles varied from 100 to 180 nm. The cytotoxicity of Arg-CS and their complexes with plasmid DNA were determined by MTT assay for HeLa cells, and the results suggested that Arg-CS/DNA complexes were slightly less toxic than Arg-CS. Moreover, the derivative alone and their complexes showed significantly lower toxicity than PEI and PEI/DNA complexes, respectively. Taking HeLa cells as target cells and using pGL3-control as reporter gene, the luciferase expression mediated by Arg-CS was greatly enhanced to about 100 folds compared with the luciferase expression mediated by chitosan at different pH media. These results suggest that Arg-CS is a promising candidate as a safe and efficient vector for gene delivery and transfection.     

Pollen flux and vertical dispersion in coniferous and deciduous broadleaved mixed forest in the Changbai Mountains

The pollen flux in coniferous and deciduous broadleaved mixed forest in the Changbai Mountains is presented in one year's experiments. The results indicate that arboreal pollen percentages are more than 65% and pollen flux is higher than 5000 grain·cm-2·a-1,while less than 2% and lower than 1000 grain·cm-2·a-1 for shrubby pollen,and less than 20% and lower than 3000 grain·cm-1·a-1 for herbaceous pollen for most samples at different heights. The pollen assemblages are similar to those in the samples under 8 m height where Pinus and Ouercus are dominant and followed by the few non-local pollen types,and Fraxinus percentages are high with a few non-local pollen types at 16 m to 32 m height as well as non-local pollen clearly increased at 40 m height. Comparisons between pollen assemblages and vegetation composition suggest that similarities are higher for pollen trap samples than for surface moss samples.