提高自组织线性表查找性能的新方法

自组织线性表在非等概率查找中具有较好的效率。本文在原有3种基本构造策略的基础上，提出一种新方法——移至中位策略。该策略优化自组织线性表中记录的调整方式，减少了累计记录比较次数，从而提高了查找响应速度。在实验测试中，提出平稳的查找过程和非平稳的查找过程的概念，并分别设计相应的测试用例。实验结果表明，移至中位策略的综合性能最好。     

Site occupancy and enhanced luminescence of broadband NIR gallogermanate phosphors by energy transfer

Super broadband near-infrared (NIR) La₃Ga₅GeO₁₄(LGGO): Cr³⁺ phosphor is in urgent needs for food testing. Unfortunately, it suffers from poor luminescence intensity in applications. Herein, the enhanced NIR luminescence performance can be realized in LGGO: Pr³⁺, Cr³⁺. The preferential crystallographic site of Cr³⁺ is validated on the basis of EPR spectrum, Rietveld refinement, and the first-principles DFT calculations. It is of great importance that the as-prepared phosphors can be excited by blue light (460 nm), which is beneficial to the application of blue-pumped LEDs. The critical distance of Pr³⁺ in LGGO host has been calculated by concentration-quenching method. For co-doped sample, it is observed that Cr³⁺ luminescence intensity enhancement by a factor of 3 can be achieved by doping Pr³⁺ owing to the energy transfer from Pr³⁺ to Cr³⁺. In addition, the introduction of Pr³⁺ can also improve the Cr³⁺ luminescence intensity at elevated temperature. Furthermore, using the optimized phosphor, a blue-based NIR phosphor-converted LEDs (NIR pc- LEDs) is fabricated, the forward voltage and the intensity of LED hardly change after thermal aging for 500 hours under high temperature/ high humidity condition, indicating its great reliability for NIR pc-LEDs. Therefore, LGGO:Pr³⁺, Cr³⁺ has great potential to serve as an attractive candidate in the application of blue light-excited NIR pc-LEDs in view of its capability for blue to enhanced broadband NIR conversion.     

Silica/mullite fiber composite membrane with double-layer structure for efficient sub-micrometer dust removal

Here, we developed silica/mullite fiber composite membranes with double-layer structure by a simple vacuum procedure for the removal of sub-micrometer dust. The support with three-dimensional skeleton structure exhibited high porosity (higher than 90%), low density (lower than 0.25?g/cm³) and high compressive strength (higher than 0.55?MPa) at 1000?°C. By controlling the mass ratio of silica sol to mullite fiber, we can obtain uniform and complete filtering layers with different thicknesses. The composite membranes exhibited high PM filtration efficiency with 99% for 1–10?µm, 97% for 0.5?µm and 90% for 0.3?µm. These samples had high air flow with very low pressure drop (lower than 600?Pa when airflow velocity reached 1?m/s). These results indicated that the silica/mullite fiber composite membranes were very promising for PM pollution control in the field of hot gas filtration.     

轧制温度对AZ61合金组织和电极性能的影响

为了探讨轧制温度对AZ61镁合金板材微观组织的影响,以及对电化学性能和放电性能的遗传效应,本文利用X射线衍射仪、光学显微镜和扫描电子显微镜对AZ61镁合金的微观组织结构和放电形貌进行了表征,采用极化曲线和组装镁空气电池放电方法对AZ61镁合金的电化学及放电性能进行了测试。研究表明:在300~400 ℃范围内,随着轧制温度的升高,AZ61镁合金的腐蚀电位先正移后负移再正移,腐蚀电流密度先减小后增大再减小。在350 ℃下轧制的AZ61镁合金具有最优良的耐腐蚀性能,其腐蚀电位为-1.470 V,腐蚀电流为8.415×10^-6 A/cm²。在电流密度为10 mA/cm²条件下,轧制温度为350 ℃的AZ61镁合金的放电效率和比容量均达到峰值,分别为55.97%和1 253.13 mAh/g,且其放电形貌较为光滑并伴随少量凹坑。轧制温度可以有效细化合金的微观组织结构,减少β相的含量,有利于该合金耐腐蚀性的提高和放电参数的增大。     

miR-181b promotes the oncogenesis of renal cell carcinoma by targeting TIMP3

Renal cell carcinoma (RCC) has a poor prognosis due to limited diagnosis and treatment. Thus, it is necessary to find novel prognostic biomarkers and therapeutic targets. The aberrant expression of microRNAs plays an important role in RCC oncogenesis. Tissue inhibitors of metalloproteinase 3 (TIMP3) acts as a downstream target of miR-181b. The aim of this study was to understand the role and molecular mechanism of miR-181b in RCC oncogenesis. The results showed that miR-181b expression was significantly higher in RCC tumour tissues, especially in those with significant invasion or metastasis. miR-181b overexpression promoted proliferation and migration of the RCC cell line 786-O, while miR-181b knockdown had the opposite effect. In addition, miR-181b was inversely correlated with TIMP3 expression in RCC tumour tissues. miR-181b overexpression reduced TIMP3 expression in RCC cell line 786-O or OS-RC-2, while miR-181b knockdown had the inverse effect. Mechanistically, a luciferase reporter assay confirmed the binding sites of miR-181b on the 3’-UTR of TIMP3, confirming the targeting effect of miR-181b on TIMP3. Overall, miR-181b promotes the development and progression of RCC by targeting TIMP3 expression, indicating the potential use of miR-181b in the diagnosis and treatment of RCC.     

光学显微定位系统定位精度分析

为了提高光学显微定位系统对细胞微生物识别定位的精度：一方面，必须改进手眼标定方法；另一方面，需要提高全局图像识别的准确性，因此，提出一种两步法对系统进行手眼标定。首先，通过标定固定靶标来确定系统原点，并得到视觉模块相对于系统原点的转换关系；然后，根据每次拍照的起始点位置、拍照的数量和移动的步长求解出全局图像相对于系统原点的转换关系；最后，为了进一步提高全局转换关系的准确度，提出一种基于傅里叶变换的误差矫正方法，利用傅里叶变换求解出视觉模块在移动过程中的误差，并加入系统进行补偿。实验结果表明，误差补偿之后，系统X轴方向的误差均值从10.23 μm降为-0.002 μm，Y轴方向的误差均值从6.9 μm降为-0.50 μm，显微定位系统的平均定位精度达到了99%以上。结果表明，所提方法可很好地用于光学显微定位系统对细胞微生物进行高精度的自动化抓取。     

单乙醇胺酰胺化改性羊毛脂的反应研究

通过正交实验设计对单乙醇胺酰胺化改性羊毛脂的反应进行了研究。研究结果表明,在m_(羊毛脂)∶m_(单乙醇胺)=100∶4时,较佳的酰胺化反应条件为:温度125℃,时间4h,在此条件下,单乙醇胺的转化率达到90.37%。当羊毛脂与单乙醇胺质量比为100∶2、100∶4、100∶6、100∶8时,所得酰胺化羊毛脂的羟值分别为55.83mg KOH·g~(-1)、72.94mg KOH·g~(-1)、79.47mg KOH·g~(-1)、89.02mg KOH·g~(-1)。此外,通过FTIR对酰胺化羊毛脂的结构进行了表征。     

棉秆拉拔力影响因素的分析及试验

棉秆拉拔力是设计棉花拔秆机的一个重要指标参数,而棉秆拉拔力的测定将受到其它因素的影响,为了探讨拔秆位移、棉秆直径、土壤含水率、土壤紧实度、起拔角度等因素对棉秆拉拔力的影响,笔者设计了棉秆拉拔力的测定试验方案并进行了棉秆拉拔力的测定试验。试验结果表明:棉秆直径与起拔力呈正相关回归关系,相关系数为0.861。土壤含水率越高,起拔力越小;土壤紧实度越大,起拔力越大。起拔角度对起拔力具有一定的影响,拉拔力与水平呈30°~45°时,起拔力较小。     

高速纺纱锭子弹性管减振机制与振动特性

为探究锭子弹性管的减振机制,将其开螺旋槽部分作为矩形弹簧模型处理,建立了减振弹性管的抗弯刚度及底部振幅的理论数学模型,并利用MatLab仿真分析了减振弹性管关键结构参教与其抗弯刚度和底部振动特性的耦合关系,同时结合有限元仿真及模态测试得到弹性管各阶固有频率。研究结果表明:随着槽宽和圈数的增大,刚度降低,底部振幅增加;随着壁厚、螺距、螺旋升角、弹性模量的增大,刚度增加,底部振幅降低;弹性管固有频率和锭子系统共振频率区间一致,且工作频率有效避开了共振频率。