Dynamical analysis of boundary behaviors of current-controlled DC–DC buck converter

Nonlinear Dynamics - In this paper, the current-controlled DC–DC buck converter from a new perspective are studied through the switching theory of flow, and the analytical conditions of the...     

GDX—硅胶混合薄层色谱板的效率和定量性能

对用ＧＤＸ－１０２－硅胶Ｇ、有机粘合剂研制出的混合薄层板进行性能测试，评价了其在硝基苯胺异构体、酸性食品染料分离测试方面的应用，得到好的结果。     

非线性信道判决反馈递归神经网络自适应均衡器

针对存在严重符号间串扰及轻度非线性畸变的数字信道，提出了一种判决反馈递归神经网络为均衡器，它将传统的线性信道判决反馈结构巧妙地融入递归神经中，在自适应训练时用期待２信号代替判决反馈信号。     

山楂种子休眠与萌发生理研究 Ⅳ.山楂种子内果皮及种皮与种子休眠的关系

通过对１９９４年和１９９５年采收的山楂种子进行层积、发芽、组织培养、生活力测定、ＧＡ３处理等多种方法进行研究认为，层积中山楂种子先解除休眠而后破壳；种子子叶休眠时间短，并可在干藏条件下解除休眠，休眠解除后，种皮抑制其生长；在种子发育过程中，子叶进入休眠前，种皮对子叶生长有一定作用；干藏７个月以内的种子，去除种皮或去除种皮及子叶，胚芽、胚轴、胚根不能萌发     

Synthesis,characterization, and thermal properties of novel silicon 1,1,3,3-tetramethylguanidinate derivatives and use as single-source chemical vapor deposition precursors

A series of chemical vapor deposition (CVD) precursors have been synthesized by a single-step reaction of 1,1,3,3-tetramethylguanidine and a variety of silicon chlorides. The structures of the 1,1,3,3-tetramethylguanidinate-based compounds were verified by ¹H NMR, ¹³C NMR, XPS, EI-MS, and elemental analysis. The thermal stability, transport behavior, and vapor pressures of these compounds were evaluated by simultaneous thermal analyses (STA). These compounds are highly stable and those in liquid form are very volatile. Silicon carbonitride (SiCN) thin films were prepared by using bis (tetramethylguanidine)-dimethyl-silane as the precursor in helicon wave plasma chemical vapor deposition (HWP-CVD). The properties of the films were investigated by SEM, AFM, and XPS. The results showed that the films have good uniformities, low friction coefficient, and high hardness, enabling the films for fabrication of semiconductor devices.     

Booting the electrochemical properties of Fe-based anode by the formation multiphasic nanocomposite for lithium-ion batteries

Fe-based compounds with good environmental friendliness and high reversible capacity have attracted considerable attention as anode for lithium-ion batteries.But,similar to other transition metal oxides(TMOs),it is also affected by large volume changes and inferior kinetics during redox reactions,resulting in the destruction of the crystal structure and poor electrochemical performance.Here,Fe_3O_4/C nanospheres anchored on the two-dimensional graphene oxide as precursors are phosphated and sintered to build the multiphasic nanocomposite.XRD results confirmed the multiphasic nanocomposite composed of Fe_2O_3,Fe_3O_4 and Fe_3PO_7,which will facilitate the Li~+ diffusion.And the carbonaceous matrix will buffer the volume changes and enhance electron conduction.Consequently,the multiphasic Febased anode delivers a large specific capacity of 1086 mAh/g with a high initial Coulombic efficiency of 87% at 0.1 C.It also has excellent cycling stability and rate property,maintaining a capacity retention of～87% after 300 cycles and a high reversible capacity of 632 mAh/g at 10 C.The proposed multiphasic structure offers a new insight into improving the electrochemical properties of TMO-based anodes for advanced alkali-ion batteries.     

d-f跃迁发光稀土配合物研究进展

稀土配合物独特的发光性质使其在众多领域有很大的应用价值.其中,d-f跃迁发光稀土配合物具有跃迁宇称允许、激发态寿命短和光谱可调等特点,但相关研究还有待进一步深入.本文介绍了稀土配合物的发光机制,综述了具有d-f跃迁发光性质的稀土配合物(主要是Ce3+,Eu2+,Yb2+和Sm2+配合物)的研究进展,并初步总结了配合物分...     

铝－5＇－硝基水杨基荧光酮－溴化十六烷基吡啶显色反应的研究及应用

本文研究了铝－５＇－硝基水杨基荧光酮（５＇－ＮＳＦ）－溴化十六烷基吡啶（ＣＰＢ）体系的显色条件。试验结果表明，在ｐＨ４．５～６．０范围内，铝与５＇－ＮＳＦ及ＣＰＢ形成紫红色的三元配合物，其最大吸收波长为５５８ｎｍ，摩尔吸光系数为１．３×１０￣５，配合物的组成为Ａｌ：５＇－ＮＳＦ：ＣＰＢ＝１：２：２。铝浓度在０～４μｇ／２５ｍＬ范围内符合比耳定律。方法用于石灰石、石英沙、石膏中铝的测定，结果令人满意。     

表面活性剂流动相用于混合固定相薄层色谱

将表面活性剂流动相用于ＧＤＸ与硅胶Ｇ混合固定相薄层色谱,用表面活性剂、乙醇和水的混合流动相对一些水溶性食品染料及指示剂等进行了分离,得到满意的结果,可以部分代替非极性键合相薄板。     

山楂苗木根系药剂处理的生理效应

用α—萘胺法、纸层析法和比色法对NAA处理的山楂苗木根系活力、氨基酸种类和含量分别进行了测定;同时用垂直板型聚丙烯酰胺凝胶电泳法对山楂叶和根内的过氧化物同工酶的酶谱进行了分析。结果表明,NAA处理能增加根内氨基酸种类和含量,也提高了根系活力。10mg·kg~(-1)NAA处理对根和叶内过氧化物同工酶的酶带和酶量均有影响,而5mg·kg~(-1)处理的与对照类似。