聚酰亚胺、聚砜、聚醚砜及其共混改性中空纤维膜用于醇/醚气相分离的研究

甲醇／ 甲基叔丁基醚的分离是目前具有实用意义的重要研究课题之一,采用气流吹扫式操作,研究了聚酰亚胺、不同结构的聚砜中空纤维膜在不同操作条件下,对甲醇／ 甲基叔丁基醚气相混合体系的分离性能,也研究共混改性对分离膜性能的影响。结果表明,各种材料的膜具有相近的分离行为,即随着气相中甲醇含量的增加,透过通量逐渐增大而分离系数逐渐减小,聚酰亚胺膜具有适中的透过通量,但具有很高的分离系数,在甲醇浓度低于２０ ％ 时,分离系数可达数千。采用聚醚砜共混改性的聚酰亚胺膜在未明显降低透过通量的条件下,使醇／ 醚分离系数大幅度提高,有很好的应用前景。     

Fast reversible electron transfer for photosynthetic reaction center from wild type Rhodobacter sphaeroides re-constituted in polycation sandwiched monolayer film

Direct reversible electron transfer for photosynthetic reaction center from wild type Rhodobacter sphaeroides re-constituted in polycation sandwiched monolayer film was observed in this work. The redox potential E0' = 0.46 V vs. NHE for first primary donor redox couple P/P+ was accurately measured from reversible CV or SWV peaks, which were quite close to those obtained from optic redox titration method. Reaction center (RC) in film was found re-constituted in such an ordered way that the orientation of RC favored the electron transfer in film. Thus, the protein electroactivity seems to be turned on in this artificial biomimic thin film. Furthermore, RC in the film features a photo-induced redox-peak fluctuation, suggesting an intact and functional state for RC in such film. Redox peaks were also found dependent of pH, implying a proton-coupled electron transfer occurring in film. Charge recombination was observed accompanied with change of electrochemical driving force. Electrochemical model assuming several classes of electroactive sites in the films on the electrode with a dispersion of standard potentials successfully fits SWV experimental data at different pulse height and frequency.     

氯原子与丙烷反应的准经典轨线研究

氢原子取代反应为化学反应动力学的研究提供了许多有用的信息,人们对这些轻原子转移反应在理论和实验上都进行了大量研究［１］．最近,一些实验对Ｃｌ原子与烃反应提供了直接信息．Ｓｉｍｐｓｏｎ等［２］利用核抽取的方法测量相关态和散射分布来研究Ｃｌ原子与振动激发态...     

VA族元素氢化物的紫外光解和多光子电离Ⅱ. PH3的多光子电离光谱

用染料激光器在波长为300-640 nm范围内扫描, 观察到PH_3的一系列多光子电离光谱。其中351-398 nm的近二十条谱带, 其能级间隔约263 cm~(-1), 拟归属于通过Ã态的(2+1)电离谱。在460-495 nm的弱谱, 428-452 nm的六条谱带和385-398 nm之间的四条谱带, 则分别认证为相应于经历了B, C和D态的(3+1)MPI光谱。求得B态的项值T_0≤60729 cm~(-1), D态的T_0≤75567 cm~(-1), 而D态的反演振动频率ω_2为510 cm~(-1).     

Oxygen harvesting from carbon dioxide: simultaneous epoxidation and CO formation

Due to increasing concentrations in the atmosphere, carbon dioxide has, in recent times, been targeted for utilisation (Carbon Capture Utilisation and Storage, CCUS). In particular, the production of CO from CO₂ has been an area of intense interest, particularly since the CO can be utilized in Fischer–Tropsch synthesis. Herein we report that CO₂ can also be used as a source of atomic oxygen that is efficiently harvested and used as a waste-free terminal oxidant for the oxidation of alkenes to epoxides. Simultaneously, the process yields CO. Utilization of the atomic oxygen does not only generate a valuable product, but also prevents the recombination of O and CO, thus increasing the yield of CO for possible application in the synthesis of higher-order hydrocarbons.

Selective formation of atomic oxygen to form epoxides in a waste free process is reported. Simultaneously generating carbon monoxide from carbon dioxide for further use.     

一种新颖的实现冷原子或冷分子囚禁的可控制光学四阱及其二维光学晶格

原子光学晶格为精确操控中性原子和研究某些基本物理问题提供了一种方法。提出了一种利用单光束照明余弦型振幅光栅与透镜组合系统实现冷原子或冷分子囚禁的可控制光学四阱新方案,计算了四阱的光强分布,讨论了从光学四阱到双阱或单阱的演化过程,并导出了光学四阱的几何参量、光强分布、强度梯度及其曲率与光学透镜系统参量间的解析关系,获得了四阱间距与光栅空间频率的关系。研究表明通过改变余弦光栅的空间频率即可实现从光学四阱到双阱或单阱的连续双向演化。     

A CRISPR/Cas12a-responsive dual-aptamer DNA network for specific capture and controllable release of circulating tumor cells

The separation and detection of circulating tumor cells (CTCs) have a significant impact on clinical diagnosis and treatment by providing a predictive diagnosis of primary tumors and tumor metastasis. But the responsive release and downstream analysis of live CTCs will provide more valuable information about molecular markers and functional properties. To this end, specific capture and controllable release methods, which can achieve the highly efficient enrichment of CTCs with strong viability, are urgently needed. DNA networks create a flexible, semi-wet three-dimensional (3D) microenvironment for cell culture, and have the potential to minimize the loss of cell viability and molecular integrity. More importantly, responsive DNA networks can be reasonably designed as smart sensors and devices to change shape, color, disassemble, and giving back to external stimuli. Here, a strategy for specifically collecting cells using a dual-aptamer DNA network is designed. The proposed strategy enables effective capture, 3D encapsulation, and responsive release of CTCs with strong viability, which can be used for downstream analysis of live cells. The programmability of CRISPR/Cas12a, a powerful toolbox for genome editing, is used to activate the responsive release of captured CTCs from the DNA network. After activation by a specified double-strand DNA (dsDNA) input, CRISPR/Cas12a cleaves the single-stranded DNA regions in the network, resulting in molecular to macroscopic changes in the network. Accompanied by the deconstruction of the DNA network into fragments, controllable cell release is achieved. The viability of released CTCs is well maintained and downstream cell analysis can be performed. This strategy uses the enzymatic properties of CRISPR/Cas12a to design a platform to improve the programmability and versatility of the DNA network, providing a powerful and effective method for capturing and releasing CTCs from complex physiological samples.

The separation and detection of circulating tumor cells (CTCs) have a significant impact on clinical diagnosis and treatment by providing a predictive diagnosis of primary tumors and tumor metastasis.     

Qualitative and Quantitative Analysis of Ejiao-Related Animal Gelatins through Peptide Markers Using LC-QTOF-MS/MS and Scheduled Multiple Reaction Monitoring (MRM) by LC-QQQ-MS/MS

Donkey-hide gelatin, also called Ejiao (colla corii asini), is commonly used as a food health supplement and valuable Chinese medicine. Its growing popular demand and short supply make it a target for fraud, and many other animal gelatins can be found as adulterants. Authentication remains a quality concern. Peptide markers were developed by searching the protein database. However, donkeys and horses share the same database, and there is no specific marker for donkeys. Here, solutions are sought following a database-independent strategy. The peptide profiles of authentic samples of different animal gelatins were compared using LC-QTOF-MS/MS. Fourteen specific markers, including four donkey-specific, one horse-specific, three cattle-specific, and six pig-specific peptides, were successfully found. As these donkey-specific peptides are not included in the current proteomics database, their sequences were determined by de novo sequencing. A quantitative LC-QQQ multiple reaction monitoring (MRM) method was further developed to achieve highly sensitive and selective analysis. The specificity and applicability of these markers were confirmed by testing multiple authentic samples and 110 batches of commercial Ejiao products, 57 of which were found to be unqualified. These results suggest that these markers are specific and accurate for authentication purposes.     

Integration of cobalt selenide nanocrystals with interlayer expanded 3D Se/N Co-doped carbon networks for superior sodium-ion storage

Rational electrode structure design is of great significance for realizing superior Na⁺storage performance.Herein,a metal salt-induced polymer blowing-bubble approach followed by selenization procedure is developed to in-situ generate abundant sub-10 nm CoSe₂ nanocrystals on 3D Se/N co-doped carbon networks(CoSe₂@3DSNC).The phase transition from Co to CoSe₂ and the incorporation of Se into the carbon layer are realized simultaneously to establish above configuration,in which the CoSe₂ nanocrystals are anchored on interlayer expanded carbon networks.Such unique configuration endows electrode with lower Na+diffusion energy barrier,higher Na+storage capability and better structural durability.Reflected in SIBs,the optimized CoSe₂@3 DSNC delivers superior rate capability(310 m Ah g^-1 at 10 A g^-1)and excellent longterm cycling stability(409 m Ah g^-1 after 1200 cycles at 5 A g^-1).Moreover,this configuration can also be obtained in other metal selenides-carbon composite through a similar approach.     

波传播计算中的人工边界条件

对无限介质中波传播进行有界区域近似计算时,需要提出人工边界条件.本文分别就连续介质和离散晶格简要介绍一些典型的人工边界条件,包括精确人工边界条件和局部人工边界条件.