7 research outputs found

    福建省人力资源管理学科发展研究报告

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    人力资源管理学科发展短却迅速,福建省人力资源管理学科发展也很迅猛。本研究从人力资源开发、战略人力资源管理、招聘与就业、绩效管理、薪酬管理、职业发展、员工关系管理、团队管理、跨文化管理、闽台人才交流合作等方面,对福建省人力资源管理研究者研究成果或人力资源管理研究者在福建省学习期间的研究成果进行综述。分析福建省人力资源管理学科发展的趋势,提出福建省人力资源管理学科发展的对策与建议

    微/纳米氧化锌(ZnO)的生长、性质及其应用研究

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    纳米氧化锌(ZnO)是一种直接宽带隙半导体材料,室温下其禁带隙宽为本3.37 eV,激子束缚能为60 meV。纳米ZnO有明显的尺寸效应、表面和界面效应等,物理化学性能优越。在压电材料、铁电材料、平面显示、表面声波、传感器、场发射器件、激光、光催化等方面有着广泛的用途。近年来,对纳米ZnO材料的研究成为国内外的一个热点。 本论文研究了用化学气相沉积(CVD)法制备微/纳米ZnO材料。通过控制实验条件,合成了多种特殊结构和形貌的微/纳米ZnO材料,并用扫描电子显微镜(SEM)、高分辨率透射电镜(HR-TEM)、X-射线衍射仪(XRD)、Raman光谱和光致发光(PL)等对材料的结构和光学性能进行了表征。采用CVD法,在温度为630 °C,氧气流量为15 sccm,氩气流量为300 sccm的条件下,制备了一种纳米带冠四足状ZnO(T-ZnO)。此结构ZnO材料的每根足顶端均有一规则的六方帽形结构,具有很大的比表面积。实验结果表明:合成的ZnO材料为纤维锌矿结构单晶,并且沿着(0001)方向生长;室温下的PL谱有两个激发峰,一个是在393 nm处相对较弱的近带紫外峰,另一个是在511 nm处强峰。而材料在600 °C下氧气中退火30 min后,511 nm附近的绿光激发辐射峰则基本消失了,这说明在511 nm处的绿光激发辐射峰可能是由于氧空位引起的。此外,通过改变实验条件,还得到了其他多种结构的微/纳米ZnO材料。 通过大量实验,找到了一种在低温下合成微/纳米ZnO材料的新方法,即水蒸气氧化法。用ZnI2作为锌源,水蒸气作为氧化剂,实验温度在300~500 °C范围内,大大低于通常CVD法的500~1500 °C。采用此法,用硅做基底,得到了一系列有趣的实验结果,大多数情况下ZnO纳米晶自组装成很规则的圆。而在瓷舟中收集到的纳米ZnO跟普通CVD法结果相似,可以得到锥状、棒状等结构的纳米晶,但其生长方式与硅基底上的有很大差别。此外,用水蒸气氧化法,还实现了ZnO纳米晶在碳纳米管(CNTs)上的直接生长,而且其PL性能增强,这可能是纳米ZnO和CNTs相互耦合的结果。在700 °C温度下,以锌粉和ZnI2作为锌源,用水蒸气作为氧化剂,在硅基底的正反面分别得到了纳米棒和纳米推子阵列。此外,还对水蒸气氧化法的化学反应机理进行了分析,实验结果证明:固态ZnI2在受热和一定真空度下先蒸发成ZnI2分子,ZnI2分子遇到水蒸气发生反应生成偶极ZnO分子,这些ZnO偶极分子在硅基底上通过静电力自组装成特殊的几何形状。 此外,还通过分子动力学模拟的方法,对材料的力学性能进行了研究,得到了ZnO的弹性常数和体弹性模量,模拟值跟其他研究人员的实验和模拟结果吻合得很好,并估出算了ZnO晶体的表面能和断裂韧性。 本论文还对制备材料的光催化性能进行了系统的研究,采用CVD法制备ZnO,对铬黑T(EBT)进行光催化降解实验。通过正交实验方法,得到了ZnO催化降解EBT的最佳工艺条件,即催化剂用量为5 g/L,光照强度为120 W,反应温度为20 °C,反应时间为120 min,EBT浓度为10 mg/L,溶液pH值为4。 在最佳实验条件下,20分钟内有95%的EBT被降解完,30分钟内则全部降解。因此,ZnO在EBT的降解中催化效率很高,在废水处理中具有潜在的应用前景

    An EBSD method for identifying growth direction of tetrapod-like ZnO particles

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    发展了利用扫描电子显微镜(SEM)与电子背散射衍射系统(EBSD)对微晶颗粒空间取向进行表征的新方法,对以气相氧化方法制备的纳米晶ZnO颗粒的生长方向进行了测量。在样品台两个不同的倾转角度下采集两幅ZnO颗粒图像,对这两幅图做图像分析,测量各枝晶臂在样品台不同倾转角时的投影角度,可以确定Zn0颗粒枝晶臂的生长方向在样品台坐标系中的空间取向,并获得各枝晶臂的长度扣夹角。由EBSD确定ZnO颗粒对应的枝晶臂晶格坐标与样品台坐标之间的空间几何关系。并根据坐标变换关系可确定枝晶臂空间生长方向的晶体学取向是沿[0001]方向

    Piezoelectricity of ZnO films prepared by sol-gel method

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    ZnO piezoelectric thin films were prepared on crystal substrate Si(111) by sol-gel technology, then characterized by scanning electron microscopy, X-ray diffraction and atomic force microscopy (AFM). The ZnO films characterized by X-ray diffraction are highly oriented in (002) direction with the growing of the film thickness. The morphologies, roughness and grain size of ZnO film investigated by AFM show that roughness and grain size of ZnO piezoelectric films decrease with the increase of the film thickness. The roughness dimension is 2.188-0.914 nm. The piezoelectric coefficient d(33) was investigated with a piezo-response force microscope (PFM). The results show that the piezoelectric coefficient increases with the increase of thickness and (002) orientation. When the force reference is close to surface roughness of the films, the piezoelectric coefficient measured is inaccurate and fluctuates in a large range, but when the force reference is big, the piezoelectric coefficient d(33) changes little and ultimately keeps constant at a low frequency

    Growth of ZnO Nanotetrapods with Hexagonal Crown

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    ZnO nanotetrapods with hexagonal crown were synthesized on a silicon wafer by vapor transport process at a low temperature of 630 °C and normal pressure without the presence of catalysts. The results demonstrated that the as-synthesized products with slender legs and regular hexagonal crown are single crystal with wurtzite structure and preferentially grow up along 001 direction. Photoluminescence spectra revealed that the green emission originated from oxygen vacancies overwhelmed that of the near-band-edge ultraviolet peak, which suggests the peculiar-shaped nanotetrapods may have potential applications in multichannel nano-optoelectronic devices

    Growth and optical properties of peculiar ZnO tetrapods

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    Regular ZnO tetrapods with different morphologies have been obtained on Si(100) substrate via the chemical vapour deposition approach. Varying the growth temperature and gas rate, we have obtained different structured ZnO materials: tetrapods with a large hexagonal crown, a flat top and a small hexagonal crown. The results suggest that these tetrapods are all single crystals with a wurtzite structure that grow along the (0001) direction. However, photoluminescence spectra shows that their optical properties are quite different: for those with large hexagonal crown, the green emission overwhelms that of the near band-edge (NBE) ultraviolet (UV) peak, while others have only a strong NBE UV peak at ~386 nm

    Piezoelectricity Of Zno Films Prepared By Sol-Gel Method

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    ZnO piezoelectric thin films were prepared on crystal substrate Si(111) by sol-gel technology, then characterized by scanning electron microscopy, X-ray diffraction and atomic force microscopy (AFM). The ZnO films characterized by X-ray diffraction are highly oriented in (002) direction with the growing of the film thickness. The morphologies, roughness and grain size of ZnO film investigated by AFM show that roughness and grain size of ZnO piezoelectric films decrease with the increase of the film thickness. The roughness dimension is 2.188-0.914 nm. The piezoelectric coefficient d(33) was investigated with a piezo-response force microscope (PFM). The results show that the piezoelectric coefficient increases with the increase of thickness and (002) orientation. When the force reference is close to surface roughness of the films, the piezoelectric coefficient measured is inaccurate and fluctuates in a large range, but when the force reference is big, the piezoelectric coefficient d(33) changes little and ultimately keeps constant at a low frequency
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