基于PCIe总线的双路1394B接口模块设计与实现

为了满足航电系统中前端传感器捕获的图形图像数据实时传输的需求,设计并实现了基于PCIe总线的双路1394B接口模块。该模块通过PCIe接口与主机交互,采用S400β传输模式,软件设计符合标准OHCI规范,支持AS5643协议,异步流包数据收发采用链式队列管理,主机与1394B控制器之间通过DMA操作,实现大数据块的并行处理,两路1394B相互独立,显著提升数据传输性能。测试验证结果表明,该模块具备带宽高、可靠性高、CPU资源占用率低等特点,已在某项目获得成功应用,实现了图形图像数据的实时传输,满足系统设计要求,表现出了良好的稳定性和适应性,具有实践应用价值。     

Uniform chitosan hollow microspheres prepared with the sulfonated polystyrene particles templates

Biodegradable chitosan hollow microspheres have been fabricated by employing uniform sulfonated polystyrene (PS) particles as templates. The chitosan was adsorbed onto the surface of the sulfonated polystyrene templates through the electrostatic interaction between the sulfonic acid groups on the templates and the amino groups on the chitosan. Subsequently, the adsorbed chitosan was crosslinked by adding glutaraldehyde. After the removal of the sulfonated polystyrene core, chitosan hollow microspheres were obtained. The longer the sulfonation time used, the smaller the size of the hollow particles and the thicker the chitosan wall obtained. Fourier transform infrared spectrometry was used to characterize the component of the microspheres. The morphologies of the PS templates and the chitosan microspheres were observed by transmission electron microscopy and scanning electron microscopy. The controlled release behavior of the chitosan hollow microspheres was also primarily investigated.     

中国大戟属植物中二萜成分的化学及生物活性

大约有80种大戟属植物广泛分布于我国,并在民间用来治疗皮肤病、水肿、结核或作为泻药和利尿剂使用.本文综述了近20年来中国产大戟属植物中14个骨架类型共150多个二萜类成分的化学研究,包括最近报道的4个具有新骨架的二萜和2个二聚体.中国产大戟属植物中的一些二萜类成分具有抗肿瘤、抗病毒、促进神经生长因子增长、皮肤刺激、致癌以及镇痛安神的活性.本文还就大戟属中二萜类成分可能的生源代谢途径提出了假设,并对该属未来的研究进行了展望.     

Synthesis of an ordered porous carbon with the dual nitrogen-doped interfaces and its ORR catalysis performance

Both nitrogen-doping feature and pore structure are critical factors for developing nitrogen-doped carbons based catalysts with a high performance toward oxygen reduction reaction(ORR).Herein,a simple one-step CVD of acetylene and acetonitrile vapor method using silanized SBA-15 as a template has been developed to synthesize an ordered porous carbon(OPC) with dual nitrogen-doped interfaces.The optimized sample as prepared with the CVD of 4 h at 750℃ contains two types of ordered mesopores that one type is the ordered cylindrical pores inheriting from the pores of SBA-15 and has a pore width of4.0~5.0 nm,the other type is the ordered quasi-hexagonal pores with a width of 3.0~4.0 nm produced by etching the pore walls of SBA-15.These two types of pores whose pore walls are built by the nitrogen doped carbon layers resulted by the CVD and thus it actually makes the dual nitrogen-doped interfaced OPC(DN-OPC).Meanwhile,DN-OPC contains a few of micropores and a large SSA of 1430 m~2/g.This dualordered pores and dual nitrogen-doped interfaces cannot only facilitate mass transport but also utilize the active sites of DN-OPC for ORR.Therefore,as metal-free ORR catalyst,DN-OPC exhibits a good activity close to commercial Pt/C catalyst,and an excellent durability and methanol tolerance.     

气相色谱–质谱法测定塑胶中磷酸三(二甲苯)酯

建立气相色谱–质谱联用测定塑胶中磷酸三(二甲苯)酯类化合物的方法。以甲苯为萃取溶剂,对样品进行萃取,选用DB–5HT气相分离色谱柱,用气相色谱–质谱联用仪对磷酸三(二甲苯)酯进行检测。在优化实验条件下,磷酸三(二甲苯)酯在14 min内可以获得良好的分离,其质量浓度在0.05~10 mg/L范围内与色谱峰面积呈良好的线性关系,线性相关系数r=0.999 8,检出限为0.05 mg/L。测定结果的相对标准偏差为3.03%~7.32%(n=7),加标回收率为95.3%~114.6%。该方法简便快捷,灵敏度高,可用于塑胶中磷酸三(二甲苯)酯的快速检测。     

The Cyano Group as a Traceless Activation Group for the Intermolecular [3+2] Cycloaddition of Azomethine Ylides: A Five‐Step Synthesis of (±)‐Isoretronecanol

The cyano group was used as a traceless activation group for the [3+2] cycloaddition of azomethine ylides in a two‐step process, thereby providing a highly effective approach to 5‐unsubstituted pyrrolidines. The transformation includes the silver acetate catalyzed intermolecular 1,3‐dipolar cycloaddition of α‐iminonitriles and an unprecedented sodium borohydride induced reductive decyanation reaction. A diverse array of substrates is amenable to this transformation. The methodology was further extended to a five‐step total synthesis of the pyrrolizidine natural product isoretronecanol.     

Nickel(0)-Catalyzed Enantioselective [3+2] Annulation of Cyclopropenones and α,β-Unsaturated Ketones/Imines

Ni⁰-catalyzed chemo- and enantioselective [3+2] cycloaddition of cyclopropenones and α,β-unsaturated ketones/imines is described. This reaction integrates C−C bond cleavage of cyclopropenones and enantioselective functionalization by carbonyl/imine group, offering a mild approach to γ-alkenyl butenolides and lactams in excellent enantioselectivity (88–98 % ee) through intermolecular C−C activation.     

ICP-AES法同时测定锰矿石中铁、铝、钛、钙、镁、磷、钡、铅的含量

锰矿石样品用HNO3-HF-HClO4酸溶除硅后,对采用ICP-AES法测定其中的铁、铝、钛、钙、镁、磷时,同时测定钡、铅的相关条件进行了试验。主要对酸溶样能否分解重晶石或天青石等含钡矿物进行了探讨,测定了3个国家级标准样品。测定结果与标准值吻合。用标准加入法测得的钡和铅的回收率分别为96．0％-100．5％,97．1％～100．0％。用该法对含钡量较高的澳大利亚锰矿进行分析,测定结果的相对标准偏差为0-82％,并将测定结果与X荧光光谱法测定结果进行了比对。     

Synthesis of nano-LiFePO4 particles with excellent electrochemical performance by electrospinning-assisted method

Nanoscale LiFePO₄/C particles are synthesized using a combination of electrospinning and annealing. The important advantages of electrospinning technique are the production of separated nanofiber precursor, enabling the precursor particles arrangement to be changed, impeding the growth and agglomeration of the LiFePO₄ particles during the heat treatment, and contributing to the formation of nanosized LiFePO₄ particles. In this study, polyvinylpyrrolidone (PVP) is used as the fiber-forming agent in the electrospinning method, and also provides a reducing agent and carbon source. In situ carbon-coated LiFePO₄ particles are obtained by the pyrolysis of PVP during the thermal treatment. The LiFePO₄ particles are coated with and connected by interlaced carbons, and are uniformly distributed in the size range 50–80?nm. It is found that the as-prepared nanoscale LiFePO₄/C composite has a desirable electrochemical performance. It has discharge capacities of 163.5?mA?h g^?1 and 110.7?mA?h g^?1 at rates of 0.1?C and 10?C, respectively. In addition, this cathode has excellent cyclability with a capacity loss of less than 3?% at 0.1?C and 5?% at 5?C after 500 cycles. An effective synthesis and processing method is presented for obtaining nanosized LiFePO₄ with high electrochemical performance.     

Near unity quantum yield of light-driven redox mediator reduction and efficient H2 generation using colloidal nanorod heterostructures

The advancement of direct solar-to-fuel conversion technologies requires the development of efficient catalysts as well as efficient materials and novel approaches for light harvesting and charge separation. We report a novel system for unprecedentedly efficient (with near-unity quantum yield) light-driven reduction of methylviologen (MV(2+)), a common redox mediator, using colloidal quasi-type II CdSe/CdS dot-in-rod nanorods as a light absorber and charge separator and mercaptopropionic acid as a sacrificial electron donor. In the presence of Pt nanoparticles, this system can efficiently convert sunlight into H(2), providing a versatile redox mediator-based approach for solar-to-fuel conversion. Compared to related CdSe seed and CdSe/CdS core/shell quantum dots and CdS nanorods, the quantum yields are significantly higher in the CdSe/CdS dot-in-rod structures. Comparison of charge separation, recombination and hole filling rates in these complexes showed that the dot-in-rod structure enables ultrafast electron transfer to methylviologen, fast hole removal by sacrificial electron donor and slow charge recombination, leading to the high quantum yield for MV(2+) photoreduction. Our finding demonstrates that by controlling the composition, size and shape of quantum-confined nanoheterostructures, the electron and hole wave functions can be tailored to produce efficient light harvesting and charge separation materials.