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82.
DMF溶液中导电玻璃上沉积类金刚石薄膜 总被引:2,自引:0,他引:2
液相法制备类金刚石膜设备简单,操作容易,能大面积成膜,越来越受到研究者们的关注.Namba[1]以乙醇为介质,在1200V电压70℃以下沉积膜,得到了类金刚石膜;Suzuki等[2]以水乙二醇溶液为介质制膜,只得到了石墨相的碳膜;以乙醇的水溶液为介质利用电解热沉积膜,得到了玻璃碳和石墨碳,同时阴极钨发生碳化有WC和W2C生成[3];Novikov等[4]在乙炔的液氨溶液中沉积膜,Raman谱表明他们得到了类金刚石(DLC)膜;Kwiatek等[5]重复了Namba的实验,证明沉积膜主要为非晶态… 相似文献
83.
使用大规模自旋极化密度泛函理论计算研究了表面修饰和尺寸对金刚石纳米线(DNs)中氮空位(NV)色心的几何结构、 电子结构、 磁性和稳定性的影响. 理论上设计了几种不同的DNs, 这些DNs具有不同的表面修饰(干净、 氢化和氟化), 并且直径达数百个原子. 实验结果证明, 中性(NV0)和带1个负电荷(NV-)的NV色心的电子结构不受半导体表面修饰和DNs直径大小的影响, 但NV色心的稳定性对这两个因素具有不同的响应. 此外, 研究中还发现, 由于DNs中存在圆柱形表面电偶极子层, 对DNs中掺杂的NV-色心的稳定性, 表面改性诱导了不依赖尺寸的长程效应. 特别地, 对于n型氟化金刚石表面, 掺杂在DN中的NV-色心可以稳定存在, 而对于p型氢化表面, NV0则相对更稳定. 因此, 表面修饰为控制金刚石纳米线中的NV色心的电子结构和稳定性提供了一种精确有效的调控方法. 相似文献
84.
Thays de Souza Lima Fábio Ruiz Simões 《International journal of environmental analytical chemistry》2017,97(8):768-782
This study is aimed to develop an electroanalytical methodology using a boron-doped diamond electrode to determine simultaneously and selectively carbendazim (CBZ) and carbaryl (CAR). In previous studies using cyclic voltammetry oxidation, peaks were observed at 1.03 V (CBZ) and 1.44 V (CAR), with characteristics of an irreversible process controlled by diffusion of species, with a supporting electrolyte of BR buffer (0.1 mol L?1) and pH adjusted to 6.0. The differences between the potentials for both pesticides, about 400 mV, indicate the possibility of selective determination of CBZ and CAR. The square-wave voltammetric parameters were optimised. The best separation conditions were pH 6.0, square-wave frequency of 100 s?1, pulse amplitude of 50 mV and scan increment of 2.0 mV. These parameters were used to obtain the calibration curves of CBZ and CAR. An analytical curve was constructed in the range concentration of CBZ of 1.3 mg L?1 to 15.3 mg L?1 and CAR of 1.0 mg L?1 to 11.4 mg L?1, respectively. The limits of detection (LOD) and limits of quantification (LOQ) for CBZ were 0.40 mg L?1 and 1.30 mg L?1, respectively. For CAR, the LOD and LOQ were 0.30 mg L?1 and 1.00 mg L?1, respectively. Sensitivity values were 0.78 and 2.60 µA/mg L?1 for CBZ and CAR, respectively. The electroanalytical method was applied in Mikania glomerata infusions. The recovery values were 106.2% and 116.5% for CBZ and CAR, respectively. The results show that the developed method is suitable for application in medicinal plant samples. 相似文献
85.
掺杂是调控金刚石性能的一种重要手段。本文采用温度梯度法,在5.6 GPa、1 312 ℃的条件下,选用Fe3P作为磷源进行磷掺杂金刚石大单晶的合成。金刚石样品的显微光学照片表明,随着Fe3P添加比例的增加,金刚石晶体的颜色逐渐变深,包裹体数量逐渐增加,晶形由板状转变为塔状直至骸晶。金刚石晶形的变化表明Fe3P的添加使生长金刚石的V形区向右偏移,这是Fe3P改变触媒特性的缘故。红外光谱分析表明,Fe3P的添加使金刚石晶体中氮含量上升,这说明磷的进入诱使氮原子更容易进入金刚石晶格中。激光拉曼光谱测试表明,随着Fe3P添加比例的增加,所合成的掺磷金刚石的拉曼峰位变化不大,其半峰全宽(FWHM)值变大,这说明磷的进入使得金刚石晶格畸变增加。XPS测试结果显示,随着Fe3P添加比例的增加,金刚石晶体中磷相对碳的原子百分含量也会增加,这意味着添加Fe3P所合成的金刚石晶体中有磷存在。 相似文献
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88.
Consider K ≥ 2 independent copies of the random walk on the symmetric group SN starting from the identity and generated by the products of either independent uniform transpositions or independent uniform neighbor transpositions. At any time $n\in \mathbb{N}$, let Gn be the subgroup of SN generated by the K positions of the chains. In the uniform transposition model, we prove that there is a cut‐off phenomenon at time N ln(N)/(2K) for the non‐existence of fixed point of Gn and for the transitivity of Gn, thus showing that these properties occur before the chains have reached equilibrium. In the uniform neighbor transposition model, a transition for the non‐existence of a fixed point of Gn appears at time of order $N^{1+\frac{2}{K}}$ (at least for K ≥ 3), but there is no cut‐off phenomenon. In the latter model, we recover a cut‐off phenomenon for the non‐existence of a fixed point at a time proportional to N by allowing the number K to be proportional to ln(N). The main tools of the proofs are spectral analysis and coupling techniques. © 2011 Wiley Periodicals, Inc. Random Struct. Alg., 2012 相似文献
89.
We have investigated the performance of a graphite–boron composite (GBC) with 3?wt % boron as a precursor for a boron-doped diamond heater in a Kawai-type apparatus at 15?GPa. We first tested a machinable cylinder of GBC sintered at 1000°C in Ar/H2 gas (99:1 molar ratio). Boron oxide (B2O3) formed during sintering frequently hindered the GBC heater from stable operation at temperatures higher than 1400°C by producing melt throughout the heater together with oxide and/or silicates. We then rinsed the GBC heater in hydrochloric acid to remove B2O3. After rinsing, we succeeded in stably generating temperatures higher than 2000°C. We also improved a molding process of different-sized GBC tubes for convenient use and tested the molded GBC heater. It was free from the B2O3 problem. The electromotive force of the W/Re thermocouple was successfully monitored up to 2400°C. 相似文献
90.
J. Barzola-Quiquia R. Höhne M. Rothermel A. Setzer P. Esquinazi V. Heera 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(2):127-130
In this work we have investigated the changes of the magnetic
properties of highly oriented pyrolytic graphite samples after
irradiation either with ~3×1014 protons or 3.5×1013 ... 3.5×1014 iron ions with energies in
the MeV range. Our results show that iron and proton irradiations can
produce similar paramagnetic contributions depending on the
implantation temperature. However, only protons induce a
ferromagnetic effect. 相似文献