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811.
812.
The photoelectron spectra of (H2O)(n = 2-69) - and (D2O)(n = 2-23) - are presented, and their spectral line shapes are analyzed in detail. This analysis revealed the presence of three different groupings of species, each of which are seen over the range, n = 11-16. These three groups are designated as dipole boundlike states, seen from n = 2-16, intermediate states, found from n = 6-16, and bulk embryonts, starting at n = 11 and continuing up through the largest sizes studied. Almost two decades ago [J. V. Coe et al., J. Chem. Phys. 92, 3980 (1990)], before the present comprehensive analysis, we concluded that the latter category of species were embryonic hydrated electrons with internalizing excess electrons (thus the term embryonts). Recent experiments with colder expansion (high stagnation chamber pressures) conditions by Neumark and coworkers [J. R. R. Verlet et al., Science 307, 93 (2005)] have also found three groups of isomers including the long-sought-after surface states of large water cluster anions. This work confirms that the species here designated as embryonts are in the process of internalizing the excess electron states as the cluster size increases (for n > or = 11). 相似文献
813.
利用混配离子液体N-烯丙基-N-甲基吗啉氯盐(N-allyl-N-methylmorpholinium chloride,[AMMor]Cl)和1-烯丙基-3-甲基咪唑氯盐(1-allyl-3-methylimidazolium chloride,[AMIm]Cl)作为溶剂,乙酰氯为乙酰化试剂,研究了在没有催化剂条件下的纤维素的均相乙酰化反应.生成的醋酸纤维素(CA)的取代度由2.58到3.00.用FT-IR,1HNMR和13CNMR进行表征.结果表明,[AMMor]Cl/[AMIm]Cl混配的离子液体是一种良好的均相乙酰化介质,纤维素C-6,C-3和C-2三个位置上的羟基均发生了乙酰化反应,且得到纯的纤维素醋酸酯.此反应方便可控,简单高效,不仅降低了成本,离子液体比较容易回收,可以再次利用. 相似文献
814.
Fe(3+) ions in sapphire exhibit an electron spin resonance which interacts strongly with high-Q whispering gallery modes at microwave frequencies. We report the first observation of a third-order paramagnetic nonlinear susceptibility in such a resonator at cryogenic temperatures and the first demonstration of four-wave mixing using this parametric nonlinearity. This observation of an all-microwave nonlinearity is an enabling step towards a host of quantum measurement and control applications which utilize spins in solids. 相似文献
815.
We propose and demonstrate a novel scheme of ultra-wideband (UWB) doublet pulse generation using a semiconductor optical amplifier (SOA) based polarization-diversified loop (PDL) without any assistant light. In our scheme, the incoming gaussian pulse is split into two parts by the PDL, and each of them is intensity modulated by the other due to cross-gain modulation (XGM) in the SOA. Then, both parts are recombined with incoherent summation to form a UWB doublet pulse. Bi-polar UWB doublet pulse generation is demonstrated using an inverted gaussian pulse injection. Moreover, pulse amplitude modulation of UWB doublet is also experimentally demonstrated. Our scheme shows some advantages, such as simple implementation without assistant light and single optical carrier operation with good fiber dispersion tolerance. 相似文献
816.
ZHANG Xindan GONG Bowen ZHAI Jiliang ZHAO Yu LU Yonglai ZHANG Liqun XUE Jiajia 《高等学校化学研究》2021,37(3):404-410
Patients with spinal cord injury(SCI) are suffering disability and accompanying complications. Due to the complex biological processes and inhibitory microenvironment after SCI, advances in clinical treatment show obvious limitations for achieving a successful repair. Herein, we summarize recent advances in engineering strategies of using electrospun nanofibers to promote the neural regeneration and functional recovery after SCI. We firstly introduce the pathological mechanism of SCI and thus point out the challenges on the regeneration of the nerve. We then discuss the regenerative approaches by combining electrospun nanofibrous scaffolds with physical cues, biochemical cues(e.g., cells, growth factors and other biomolecules), external stimuli, and supporting materials filling in the inner lumen of the scaffolds. All these strategies have indicated their potentials to enhance the efficacy of repairing the SCI. At last, we provide a perspective on the future direction for designing the electrospun nanofibrous scaffolds in combination with imaging systems to realize the in-situ monitoring of regeneration progress for further improving the treatment outcome. 相似文献
817.
Jiangfeng Li Zijian Zhang Bowen Wang Qinpei Zhao Chenxi Zhang 《Entropy (Basel, Switzerland)》2022,24(6)
Internet users are benefiting from technologies of abstractive summarization enabling them to view articles on the internet by reading article summaries only instead of an entire article. However, there are disadvantages to technologies for analyzing articles with texts and images due to the semantic gap between vision and language. These technologies focus more on aggregating features and neglect the heterogeneity of each modality. At the same time, the lack of consideration of intrinsic data properties within each modality and semantic information from cross-modal correlations result in the poor quality of learned representations. Therefore, we propose a novel Inter- and Intra-modal Contrastive Hybrid learning framework which learns to automatically align the multimodal information and maintains the semantic consistency of input/output flows. Moreover, ITCH can be taken as a component to make the model suitable for both supervised and unsupervised learning approaches. Experiments on two public datasets, MMS and MSMO, show that the ITCH performances are better than the current baselines. 相似文献
818.
曹建勇 魏会领 刘鹤 邹桂清 杨宪福 张贤明 唐立新 罗萃文 余佩炫 耿少飞 周红霞 周博文 李青 何峰 罗怀宇 周健 任磊磊 潘春花 黄高扬 雷光玖 饶军 段旭如 《强激光与粒子束》2018,30(10):106001-1-106001-9
为开展磁约束堆芯燃烧等离子体物理实验,正在建造的HL-2M装置拟建造3条5 MW的中性束注入加热束线。简要概述了HL-2M装置NBI加热系统的总体规划,第1条5MW-NBI加热束线的设计,离子源调试实验,注入器核心部件的安装和测试结果。通过调试,目前单个离子源引出束流达到36 A,加速电压75 kV,离子束功率达到2.4 MW,脉冲宽度3 s。通过测试发现:注入器的4条离子束汇聚角误差小于±0.1°,残留离子偏转磁体的磁场测试值与模拟计算值偏差小于±5%,注入器静态真空值达到1.0×10-3 Pa。注入器采用大型非标低温泵,低温泵的抽速达到2.40×106 L/s。第1条5MW-NBI加热束线的试装和测试结果表明,该束线能够满足HL-2M装置NBI加热的技术要求。 相似文献
819.
Kathy Tou Adam Cawley Christopher Bowen David P. Bishop Shanlin Fu 《Molecules (Basel, Switzerland)》2023,28(1)
The current approach to equine anti-doping is focused on the targeted detection of prohibited substances. However, as new substances are rapidly being developed, the need for complimentary methods for monitoring is crucial to ensure the integrity of the racing industry is upheld. Lipidomics is a growing field involved in the characterisation of lipids, their function and metabolism in a biological system. Different lipids have various biological effects throughout the equine system including platelet aggregation and inflammation. A certain class of lipids that are being reviewed are the eicosanoids (inflammatory markers). The use of eicosanoids as a complementary method for monitoring has become increasingly popular with various studies completed to highlight their potential. Studies including various corticosteroids, non-steroidal anti-inflammatories and cannabidiol have been reviewed to highlight the progress lipidomics has had in contributing to the equine anti-doping industry. This review has explored the techniques used to prepare and analyse samples for lipidomic investigations in addition to the statistical analysis and potential for lipidomics to be used for a longitudinal assessment in the equine anti-doping industry. 相似文献
820.
Ph. Schidrowitz F. W. Richardson und J. L. Bowen 《Fresenius' Journal of Analytical Chemistry》1907,46(5):344-345
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