硅藻土涂料在热模法离心铸造球铁管中的应用

采用硅藻土为骨料配制的悬浊液作为涂料涂覆于管模内壁生产球铁管,论述了涂料原材料选择、涂料配制、性能及合适的施涂方式。试验表明,膨润土浆持续搅拌2h,再静止10h后配制涂料;硅藻土是涂料热模法中最合适的骨料;对于小管径的管模涂料,膨润土含量高一些,硅藻土与膨润土的质量比为(8～15):1;对于大口径管模涂料,膨润土含量稍低,硅藻土与膨润土质量比为(12～20):1,另外,有气喷涂是最佳的喷涂方式。     

刚性路面超薄混凝土罩面关键施工工艺研究

对水泥混凝土路面超薄罩面快速修补的关键施工工艺进行了分析,提出了能迅速恢复沉陷路段标高的方法,解决了刚性路面维修时间长,难度大等问题,达到了快速通车的目的。     

一种高动态短突发信号伪码快速捕获方法

根据实际的应用背景,针对高动态的突发短帧信号的特性,研究其信号快速捕获问题,提出了一种适应高动态环境,捕获时间短的捕获方法。该方法采用一种频率分割的方案,将大的多普勒频偏分割为若干小频率段,每个频率段并行处理,采用等待式的数字相关处理办法,各自完成相关积累和视频积累,并经过自适应门限判决,输出同步信号检测脉冲,完成伪码的快速捕获。     

Photoluminescence characterization of the effects of rapid thermal annealing on AlGaAs/GaAs modulation-doped quantum wells

In this study, we describe the effects of rapid thermal annealing on the electrical and optical properties of modulation-doped quantum wells (MDQWs). The sheet carrier concentration in MDQW structures which have been annealed in contact with a piece of GaAs tends to decrease with increasing annealing time due to Si auto-compensation in the doped AlGaAs regions. The high energy cut-off point of 4.2 K PL spectra, which occurs at the Fermi energy, and the 77 K PL linewidth are accurate measures of sheet carrier density. These two parameters track variations in carrier density produced by annealing. Photoluminescence spectra also provide additional insight into annealing-induced changes such as Si migration, which causes a degradation in the mobility of the two-dimensional electron gas.     

Direct and Rapid High-Temperature Upcycling of Degraded Graphite

Recycling the degraded graphite is becoming increasingly important, which can helped conserve natural resources, reduce waste, and provide economic and environmental benefits. However, current regeneration methods usually suffer from the use of harmful chemicals, high energy and time consumption, and poor scalability. Herein, we report a continuously high-temperature heating (≈2000 K) process to directly and rapidly upcycle degraded graphite containing impurities. A sloped carbon heater is designed to provide the continuous heating source, which enables robust control over the temperature profile, eliminating thermal barrier for heat transfer compared to conventional furnace heating. The upcycling process can be completed within 0.1 s when the degraded graphite rolls down the sloped heater, allowing us to produce the upcycled graphite on a large scale. High-temperature heating removes impurities and enhances the graphitization degree and (002) interlayer spacing, making the upcycled graphite more suitable for lithium intercalation and deintercalation. The assembled upcycled graphite||Li cell displays a high reversible capacity of ≈320 mAh g⁻¹ at 1 C with a capacity retention of 96% after 500 cycles, comparable to current state-of-the-art recycled graphite. The method is a chemical-free, rapid, and scalable way to upcycle degraded graphite, and is adaptable to recycle other electrode materials.     

激光再制造三维运动光束头

基于激光制造技术相关理论，设计并制造了激光同轴转动三维运动光束头。分析了三维运动光束头工艺参数对熔覆效果的影响，并讨论了其在工业应用实验中取得的效果。结果表明，该三维运动光束头能绕竖直轴转动和水平轴摆动;在参数一定的条件下，随着光束头摆动角度的增加，熔覆效果越来越不理想，理想的摆动角度为0°～45°;配合送粉头的粉末流聚焦及焦点可调功能，该光束头可以实现曲轴、螺杆、叶片等复杂型面零件的制造和再制造。     

激光快速成形过程中熔池形态的演化

采用高速摄影技术对激光快速成形过程中液态熔池的形成及其演化过程进行了实时观察。结果发现,以一定速度向前运动的激光束辐照基材时,基材表面开始熔化并形成液态熔池,经过一个较短的时间间隔(约1．0 s)后熔池深度增大至一定值,熔池长度则围绕一恒定值波动。以恒定送粉率向熔池中连续送进金属粉末时,熔池的长度和宽度逐渐减小,熔池寿命缩短。同时熔池后沿不断抬高即熔覆层厚度不断增加,最大熔深处熔池自由表面法向和激光束轴线之间的夹角由几度逐渐增大到20°～30°左右。熔池自由表面发生周期性的变化,实验观察到熔池后沿有周期性的“岛状凸起”出现和消失现象。数值计算结果证实这主要是熔池中熔体在表面张力梯度下引起的强制对流作用的结果。     

图像匹配中NCC算法的一种快速实现方法

在计算机视觉领域,图像匹配是常见的任务,基于灰度的点的匹配是常见的方法。其中又以抗噪能力强、匹配精度高的归一化互相关（NCC）算法最为常用。然而NCC算法计算量较大,常常难以满足实时处理的要求。通过引入合适的全1矩阵,让其和原图像的数据做卷积,大幅度地降低了NCC的计算量,提高了效率,仿真实验结果也证明了本文方法的有效性。     

TiO2/MXene-Assisted LDI-MS for Urine Metabolic Profiling in Urinary Disease

Cancer remains an intractable medical problem. Rapid diagnosis and identification of cancer are critical to differentiate it from nonmalignant diseases. High-throughput biofluid metabolic analysis has potential for cancer diagnosis. Nevertheless, the present metabolite analysis method does not meet the demand for high-throughput screening of diseases. Herein, a high-throughput, cost-effective, and noninvasive urine metabolic profiling method based on TiO₂/MXene-assisted laser desorption/ionization mass spectrometry (LDI-MS) is presented for the efficient screening of bladder cancer (BC) and nonmalignant urinary disease. Combined with machine learning, TiO₂/MXene-assisted LDI-MS enables high diagnostic accuracy (96.8%) for the classification of patient groups (including 47 BC and 46 ureteral calculus (UC) patients) from healthy controls (113 cases). In addition, BC patients can also be identified from noncancerous UC individuals with an accuracy of 88.3% in the independent test cohort. Furthermore, metabolite variations between BC and UC individuals are investigated based on relative quantification, and related pathways are also discussed. These results suggest that this method, based on urine metabolic patterns, provides a potential tool for rapidly distinguishing urinary diseases and it may pave the way for precision medicine.     

快速热退火对SPV法测试氧化硅片中铁的影响

研究了快速热退火(RTA)对表面光电压SPV法测试氧化硅片中铁的影响.结果表明,氧化硅片在1100℃的条件下RTA 3min后,SPV测出的铁含量大幅度地减小.由于RTA的均匀化作用,氧化硅片表层的铁浓度显著低于氧化刚结束时硅片表层的铁浓度.根据SPV测试理论,从硅片表面到少数载流子产生处这一区域的铁浓度最终决定了铁含量的测试结果,即硅片表层的铁含量代表了整个硅片的铁含量.因此,氧化硅片经RTA处理后,SPV测出的铁含量大幅度地减小.