基于扩展摄像机成像模型的自标定方法*

提出了一种基于扩展摄像机成像模型的自标定方法,将采用不同视点成像的观念转换为不同方向透视投影下分析,得到在一幅图像中同时建立三对不同方向的空间面与图像面的单应关系,进而建立不同面的圆环点绝对二次方程,实现单幅图像标定。采用长方体进行实验,模拟实验和真实图像实验均验证了这种思维方法的可行性和正确性。     

基因表达式编程中动态适应的远缘繁殖策略

传统基因表达式编程采用静态适应度函数,影响了后期进化速度和整体质量。提出了远缘繁殖策略和动态适应度函数策略,远亲繁殖并及时变换评估个体的标准,增加多样性并有利于选择优质个体;实验表明,将远缘繁殖和动态适应度函数策略结合,有效地改善了传统GEP的性能,进化代数平均下降达10%,平均最高适应度值提高7%~14%,最高适应度提高达7%以上,进化的成功率提高达30%以上。     

对成都"农家乐"旅游现状与发展的思索

"农家乐"作为一种休闲旅游形式,于二十世纪九十年代初诞生于成都,由于其回归自然的生态特性及价格低廉等原因,越来越受到各界人士,尤其是都市居民的关注和喜爱.然而,在充分肯定"农家乐"成功经验的背后,也出现了一些问题与危机.本文在对成都"农家乐"深入调查的基础上,结合其现状,认真思索"农家乐"应当如何走健康、规范、有序发展的道路.     

基于hash技术的ext3目录索引机制的改进*

针对当前广泛应用的ext3文件系统对超过一定长度的目录进行索引操作时,其性能明显下降的现象,首先对其原因进行了分析,提出一种基于hash技术的ext3目录索引问题的解决方案,并在此基础上给出了实现代码。通过几种测试平台所获得的实验数据证明了该hash技术对解决ext3性能瓶颈的有效性。     

四川盆地海相页岩气富集条件及勘探开发有利区

历经十余年探索实践,四川盆地海相页岩气勘探取得了一系列进展,锁定五峰组—龙马溪组为最有利产层,提出了一批页岩气富集高产理论,形成了集地质评价、开发优化、优快钻井、体积压裂、工厂化作业、清洁开发等为一体的勘探开发技术,探明了万亿立方米级储量的页岩气大气田。时值中国页岩气勘探发展的重要节点,回顾四川盆地海相页岩气勘探开发历程、梳理五峰组—龙马溪组页岩气在地质条件与富集规律上的成果认识、展望四川盆地海相页岩气勘探的重点接替领域,对推进盆地海相页岩气的勘探开发有积极意义。(1)四川盆地海相页岩气勘探开发经历了4个阶段：评层选区找目标阶段;浅层至中—深层先导试验阶段;浅层至中—深层示范区建设阶段;浅层至中—深层上产、深层评价、常压页岩气评价、立体开发评价、超深层和新层系探索阶段。(2)四川盆地五峰组—龙马溪组的沉积条件优越,深水陆棚相高有机质含量页岩呈连续稳定分布;页岩气主要赋存在有机孔隙中,页岩储层在纵向上集中发育,连续厚度大;川南地区和川东南涪陵区块的构造相对简单,气源持续补给、远离古/今剥蚀区和大型断裂逸散区是页岩气富集保存的有利区;目前,五峰组—龙马溪组的页岩气资源量为33.19×10<...     

油气储运科技创新成果收益递进分成评估

油气储运业务的快速发展对科技创新提出更高要求,科学量化科技创新成果转化应用后取得的经济效益,成为激励创新、驱动发展的主要瓶颈与重大命题。借鉴要素分配、分享经济和收益分成理论,立足于油气储运科技创新成果价值贡献与创效方式、技术基本结构级序,建立科技创新成果收益递进分成评估方法。研究表明：（1）油气科技创新成果转化应用取得的总体经济效益是资本、劳动、技术和管理等生产要素协同作用的结果;（2）油气储运科技创新成果的收益分成率是核心参数,由技术要素分成基准值、技术要素收益递进分成基数、技术创新强度系数等关键参数确定;（3）三级技术要素递进分成基数是实现收益递进分成的关键工具;（4）单项技术的分成比例与技术自身创新创效能力、技术阶段等密切相关。实证表明,该方法可有效解决从总体到单一油气储运技术要素经济价值量化问题,为促进油气储运科技创新发展提供支持。     

Multipath optical thermometry realized in CaSc2O4: Yb3+/Er3+ with high sensitivity and superior resolution

Design and fabrication of contactless optical thermometer with rapid and accurate performance has become a research hotspot in recent years. Herein, CaSc₂O₄: Yb³⁺/Er³⁺ is employed as the intermediary for temperature sensing under the excitation of 980 nm, which is proven to afford an ultra-sensitive and high-resolution optical thermometry in multiple ways based on the fluorescence intensity ratio (FIR) technology. The optimal thermal sensing behaviors are realized by the FIR of Er³⁺:²H_11/2 → ⁴I_15/2 to ⁴S_3/2 → ⁴I_15/2 transition, which has a relative sensitivity of 1184/T² and a minimal resolution of 0.03 K along with a maximal absolute error of 0.96 K. Besides that, the FIR between the thermally coupled Stark sublevels of Er³⁺:⁴F_9/2 manifold (FIR_R) as well as that of Er³⁺: ⁴I_13/2 manifold (FIR_N) can also provide excellent optical thermometry. The relative sensitivity of FIR_R-based and FIR_N-based optical thermometers are calculated to be 402/T² and 366/T², respectively, with a same minimal resolution of 0.09 K, which possess the potential to be used for biomedicine due to the inherent advantage of their operating wavelengths located in the biological window. The results demonstrate that CaSc₂O₄: Yb³⁺/Er³⁺ is a promising candidate for temperature sensing with multipath, high sensitivity, and superior resolution.     

Reaction behaviors and specific exposed crystal planes manipulation mechanism of TiC nanoparticles

Titanium carbide (TiC) nanoparticles with well-designed exposed crystal planes perform intriguing prospects for functional and engineering applications. In this study, a simple and controllable in situ synthesis strategy was proposed for the synthesis of TiC nanoparticles with specific morphology. Reaction behaviors suggested that most of TiC nanoparticles were formed by an instantaneous reaction between Al₃Ti and Al₄C₃ in the Al-rich melt and the resultant morphology was controlled by the discrepant growing rates of (100) and (111) crystal planes. In addition, a growth morphology control model was presented for the prediction and manipulation of the morphology of TiC nanoparticles by the doping of different alloying elements Me (Me = Cu, Mg, Mn, Zn, and Si). According to the morphological observations and density functional theory analyses including the interface energy, charge density differences, and orbital hybridization: Cu, Mg, and Zn atoms could stabilize the Al/TiC(111) interface, whereas Mn and Si atoms promoted the rapid growing and disappearance of the TiC(111) planes in the Al melt. This work provides a feasible way to intelligently design and manipulate TiC nanoparticles with desirable exposed crystal planes, and exhibits a promising prospect for personalized applications.     

Nondestructive measurements of residual stress in air plasma-sprayed thermal barrier coatings

Premature spallation of thermal barrier coatings (TBCs) is a critical issue during the service of gas turbines, and nondestructive evaluation is crucial to address this problem. Herein, a novel approach that indicates delamination by measuring the residual stress evolution of thermally grown oxide (TGO) for air plasma spraying (APS) TBCs is proposed and verified via the combination of photoluminescence piezo-spectroscopy (PLPS) and X-ray computed tomography. A mineral-oil-impregnating approach and a cold-mount low-shrinkage epoxy-mounting approach are used to alleviate the signal attenuation by pores and microcracks in APS TBCs, improving the detectable PLPS signal and X-ray transmission for stress measurement and delamination characterization, respectively. We have nondestructively measured the TGO residual stress mapping in APS TBCs and its evolution with oxidation. Furthermore, the evolution of TGO morphology and critical microcracks are obtained by X-ray computed tomography. The synchronous evolution of TGO residual stress, TGO thickness, and critical microcracks as a function of oxidation time is obtained and correlated. The transition point, as experimentally identified, at which the TGO stress starts to drop, agrees well with the critical moment of microcrack coalescence. This directly verifies that the TBC delamination can be effectively indicated by residual stress evolution of TGO in APS TBCs.     

Sintering parameter optimization of Tb3Al5O12 magneto-optical ceramics by vacuum sintering and HIP post-treatment

Transparent terbium aluminum garnet (TAG) ceramics were achieved by the vacuum sintering plus HIP post-treating from the coprecipitated TAG nanoparticles. The influences of vacuum sintering temperature and sintering aid TEOS on the optical quality of the TAG ceramics were studied. The results show that with the increase of sintering temperature, the optical quality of TAG ceramics is improved gradually, and the in-line transmittance of the TAG ceramics treated at 1720°C for 20 hours under vacuum and then HIP post-treated at 1700°C for 3 hours under 200 MPa argon gas is 81.6% at 1064 nm. The sintering additive TEOS can improve the optical quality of TAG ceramics and inhibit the valence state change of Tb³⁺ ions to Tb⁴⁺ during the annealing process. The Verdet constant of the TAG ceramics at 632.8 nm is about −178 rad·T⁻¹·m⁻¹ at room temperature, which is 1.3 times that of the commercial TGG crystals (−134 rad·T⁻¹·m⁻¹).