基于状态方程的二级倒立摆最优控制研究

主要利用状态空间方程,研究二级倒立摆的最优控制理论。通过对系统进行数学建模,再在平衡点处进行线性化处理、近似计算,得出控制矩阵;接着设计最优控制方案和控制器,以消耗能量最少为标准;最后根据计算结果,通过Matlab程序仿真,得出了上下摆的角度和小车位移的曲线图,并得出结论说明控制器的设计是成功的。     

风选工艺参数对梗丝结构的影响

为降低梗丝在后加工工序中的造碎率,对风选后输送风速和烘后梗丝含水率两个主要参数变化对梗丝结构的影响进行了测试。结果表明:①风选后的输送风速越高,梗丝的造碎率越大;②烘后梗丝含水率越高,梗丝造碎率越低;③在实际生产中,烘后梗丝含水率宜控制在13 5%左右;风选后的输送风速应在保证风分箱风选效果良好的前提下尽量调低。     

Thermal conductivity of （Sm1-xLax）2Zr2O7 （x=0, 0.25, 0.5, 0.75 and 1） oxides for advanced thermal barrier coatings

Pyrochlore oxides of general compositions, A2Zr2O7, where A is a 3+ cation (La to Lu), are promising candidate materials for ap-plications as high temperature thermal barrier coatings because of their high melting points, high thermal expansion coefficients, and low thermal conductivities. In this study, oxides of Sm2Zr2O7, (Sm0.75La0.25)2Zr2O7, (Sm0.5 La0.5)2Zr2O7, (Sm0.25La0.75)2Zr2O7 and La2Zr2O7 were prepared by solid reactions at 1600 ℃ for 10 h using Sm2O3, La2O3 and ZrO2 as the reactants. The phase compositions of these ceramic ma-terials were analyzed by X-ray diffractometer (XRD) and fourier transform infrared spectroscopy (FT-IR) methods, respectively. The micro-structure was observed by scanning electronl microscope (SEM). The thermal conductivities of these ceramic materials were measured using laser-flash method. XRD and FT-IR results showed that pure ceramic materials with pyrochlore structure were prepared successfully. SEM results indicated that microstructures of these ceramic materials were dense and grain boundaries were very clean. The La2O3 doped Sm2Zr2O7 pyrochlores (Sm0.75 La0.25)2Zr2O7 and (Sm0.5 La0.5)2Zr2O7 had lower thermal conductivity than the undoped Sm2Zr2O7. The thermal conductivity of (Sm0.25La0.75)2Zr2O7 was found to be lower than that of La2Zr2O7. The results showed that these ceramic materials had the poten-tial to be used as candidate materials for TBCs.     

资源型矿山企业的人力资源开发和管理

知识经济时代,企业竞争的重点逐渐转向对人力资源的争夺,对企业来说,知识管理、知识创新成为推动企业提高生产率、提长企业的核心竞争力的源泉。而企业人力资源作为知识和技能“承载者”,是知识经济时代企业创造独占性知识和垄断技术优势的基础。如何将知识管理背景下的人力资源转化为战略资产,创造人力资源竞争优势,并进而转化为企业持续竞争优势,是值得我们探讨的话题。     

Phase stability and elastic moduli of Cr2Nb by first-principles calculations

The phase stability and elastic moduli of Cr₂Nb are investigated by first-principles calculations. Heats of formation are calculated and compared for the three Laves phases (C15, C14, and C36). It is found that the C15 phase is the ground-state structure with the lowest energy and the C36 phase is an intermediate state between C15 and C14. These three phases, however, are very close in energy, indicating low stacking fault energies in this system. For the ground-state C15 phase, we calculate three elastic constants from which the shear and Young’s moduli are obtained. It is found that these calculated moduli are smaller than the experimental values obtained from polycrystals.     

基于FEEMD-NTEO的风电场送出线路故障定位

针对集合经验模态分解(EEMD)用于双馈风电场送出线路行波故障定位中行波检测精度不高,存在模态混叠、抗噪能力弱及故障定位实时性不好等问题,提出了一种基于快速集合经验模态分解(FEEMD)与改进Teager能量算子(NTEO)结合的行波故障定位方法。该方法利用FEEMD对故障电流行波信号进行分解,分解为平稳的固有模态分量和残差分量,消除噪声成分,保留信号的完整性;然后采用NTEO算法对分解的高频信号再次去噪,增强故障行波突变特征,精确标定行波波头。仿真结果表明,所提方法能够快速将故障行波波头精确标定,且去噪效果好,与FEEMD-TEO、EEMD-NTEO行波检测方法相比,提高了故障定位的精度和速度。     

滇中引水工程凤凰山隧洞过活动断裂带结构适应性研究

滇中引水工程输水建筑物多采用隧洞,占比高达92%,线路多次穿越区域性活动断裂带等地质条件复杂的地层,工程建设及安全运行均受到严重威胁。结合滇中引水工程隧洞穿越活动断裂带的工程设计案例,从建筑物结构型式选择以及结构对断裂带蠕滑变形及黏滑变形的适应性进行了三维仿真分析,并提出了工程运行期合理的检修年限。研究结果表明:采用短衬砌和宽变形缝结构形式可有效减小区域性活动断裂带位移产生的结构应力,大大延长了衬砌结构的使用寿命。研究结论为穿越活断裂隧洞的抗错断设计提供参考。     

基于AHP的云南少数民族地区旅游竞争力评价研究

本文首先构建了一套适用于云南省少数民族地区旅游竞争力的评价指标体系,并采用层次分析法(AHP)对云南省8个少数民族自治州作出评价,根据评价结果将其划分为4个不同旅游竞争力类型,分析了每个地区存在的优势和问题,以期为促进各地区旅游业发展提供参考。     

黑井古镇传统菜肴制法及特色探讨

传统菜肴是一个地区饮食文化的主要代表,具有重要的研究和体验价值。本文从黑井古镇特色菜肴的特点、制法及工艺等方面对黑井的饮食特色进行了归纳,以求有助于传统菜肴的传承和发展,并为美食爱好者提供参考。     

MKdV方程的新精确孤立波解

本文从MKdV方程的平凡解U0=1和U0=-1出发,考虑该方程的精确孤立波解.通过求相应Lax对的解以及对参数μ选取不同数值的方式,得到了MKdV方程的六组新孤立波解.用同一种方法求出12个精确解.