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关键词： Biodiesel  

摘要： The study effectively optimized the transesterification process of Jatropha oil to fatty acid methyl ester using response surface methodology (CCD) and Taguchi orthogonal method, leading to enhanced efficiency and product quality. The optimization of five process parameters was conducted to predict the biodiesel yield (%) from the transesterification of Jatropha oil. The procedure was made easier with the use of a nanocatalyst made from calcium oxide obtained from snail shells using the hydrothermal technique. The RSM approach yielded an optimal FAME of 94.10% under specific conditions: a methanol to oil ratio of 5 : 1, catalyst weight of 1.5 w/w, reaction temperature of 50 degrees C, reaction duration of 45 minutes, and an agitation speed of 250 rpm across 32 experimental trials. On the other hand, the Taguchi method predicted a higher FAME yield of 86.36% using specific operational parameters. These parameters included a methanol to oil ratio of 4 : 1, catalyst weight of 0.5 w/w, reaction temperature of 60 degrees C, reaction duration of 25 minutes, and an agitation speed of 200 rpm. These parameters were determined through 16 experimental trials. The RSM technique yielded impressive results with a determined coefficient of determination (R2) of 0.9943, adjusted R2 of 0.9838, predicted R2 of 0.8470, and a coefficient of variance (CV) of 0.65. On the other hand, the Taguchi method had coefficients of 0.8994, 0.7483, and 1.95. The FAME yield of RSM was slightly higher, but the Taguchi method was much more cost-efficient. The analysis of variance (ANOVA) results showed that the methanol to oil ratio had the highest influence on the yield, accounting for 49.61% of the variation. This highlights the significant impact of this factor on the overall process. The study highlights the significance of utilizing advanced techniques such as TOA and RSM, which are known for their effectiveness. The study aims to enhance the yield and efficiency of the transesterification proce

关键词： 声发射   光纤光栅阵列   撞击定位   小波分析   传感器网络  

摘要： 无损检测中使用的声发射主要是通过分析机械结构中传播的弹性波，利用生成的声波携带信息可以确定结构的完整性。为了实现对于仪器损伤的精准定位，本文提出利用正交光纤光栅传感器网络及其对称三角形布置应用于声发射定位的方法，有效减少由光纤光栅轴和声波传播方向之间的角度造成的误差。该方法基于小波变换，利用声发射源形成的兰姆波中不同频率波到达的相对时间差来求解声发射信号，并采用建立的椭圆算法实现对声发射源的定位，实验最终得到平均误差为2.95cm。本文还探究了声发射源距离对传感器接收信号的影响。该研究对仪器的损伤及缺陷定位有较大意义。

关键词： 计算机技术   车联网   入侵检测   机器学习   神经网络   长短期记忆  

摘要： 如今，我们的日常生活和通信在很大程度上依赖于网络安全。在车载网络领域，网络信息安全仍面临巨大挑战，汽车的软件和硬件组件都可能成为攻击目标，危及公共安全。在本研究中，针对上述问题提出了一种基于控制器局域网（Controller Area Network， CAN）总线数据的新型车载网络入侵检测方法，并将其命名为IncepNet方法。首先，我们选取了一个真实的汽车黑客攻击数据集（Car-Hacking Dataset），对其进行数据预处理，使用图像处理方法将该数据集中的时间序列数据按照一定规则重新组织，转换为适合作为卷积神经网络输入的图片数据。其次，优化了现有的残差网络（Inception-ResNet），并在其后添加了具有多批次归一化功能的长短期记忆神经网络（Long Short-Term Memory， LSTM）层和丢弃层（Dropout）。本研究使用了包括识别率、准确率、F1分数（F1-score）和误报次数（FAR）在内的混淆矩阵，以证明该模型具有卓越的准确性和可靠性。研究结果表明，该模型具有低误报率、高检测准确率和高检测率，且其效率明显优于以往基于其他机器学习的检测方法。

关键词： 光纤传感技术   隧道   健康监控量测  

摘要： 在隧道工程建设与运营中,健康监控量测始终起着至关重要的作用.近年来,通过应用光纤传感技术,不仅提高了监测质量和效果,也极大地增强了参建单位的风险防范能力.文章概述了隧道健康监控量测的基本内容,并以某隧道工程项目为例,从思路、系统架构设计、光纤敷设、实验测试、具体运用五个方面,对该项目进行了具体探讨,以供参考.

摘要： We present the first CCD observations of an eclipsing binary, ZTFJ015003.88+534734.1, which is a member in the open star cluster UBC 188. The observations were taken by the 1.88 m telescope at the Kottamia Astronomical Observatory (KAO) in SDSS griz bands. The latest version of the Wilson- Devinney (W-D) code was employed for photometric analysis and light curve modeling of the eclipsing binary. The results indicate that the binary system is in an over-contact configuration. The mass of the primary star (M1) is determined to be 1.293 Msun, and the mass of the secondary star (M2) is directly derived from the system's estimated mass ratio (q= M2/M1) as 0.340 times the solar mass (Msun). We investigated the color-magnitude diagram and the membership probability of the open cluster UBC 188 using the Gaia DR3 data. We determined the membership probability of the eclipsing binary ZTFJ015003.88+534734.1 using the pyUPMASK algorithm and found that its membership probability is one.

关键词： Photometry  

摘要： We present the first CCD observations of an eclipsing binary, ZTFJ015003.88+534734.1, which is a member in the open star cluster UBC 188. The observations were taken by the 1.88 m telescope at the Kottamia Astronomical Observatory (KAO) in SDSS griz bands. The latest version of the Wilson-Devinney (W-D) code was employed for photometric analysis and light curve modeling of the eclipsing binary. The results indicate that the binary system is in an over-contact configuration. The mass of the primary star (M1) is determined to be 1.293 M☉, and the mass of the secondary star (M2) is directly derived from the system's estimated mass ratio (q= M2/M1) as 0.340 times the solar mass (M☉). We investigated the color-magnitude diagram and the membership probability of the open cluster UBC 188 using the Gaia DR3 data. We determined the membership probability of the eclipsing binary ZTFJ015003.88+534734.1 using the pyUPMASK algorithm and found that its membership probability is one. © 2024, CC0.

关键词： 激光技术   太阳光泵浦激光器   复合抛物面聚光器   光纤耦合  

摘要： 为研制适用于太阳光泵浦光纤激光器的聚光系统,在分析了传统复合抛物面聚光器(CPC)用于耦合光纤的可行性及其缺陷的基础上,提出了一种改进型CPC用于光纤耦合。完成了由主级抛物面反射镜和次级改进型CPC组成的太阳光泵浦多级聚光方案,并与普通CPC和透镜组构成次级聚光器的方案以及无次级聚光器的方案进行了对比。光线追迹仿真模拟结果表明:改进型CPC能够克服普通CPC出射光线发散的缺陷,从而提高与光纤的耦合效率,当主镜接收角度在±0.55°范围内,其耦合效率维持在93.53%-96.43%,该结果优于其他方案。

关键词： 灵敏度   超声检测   试块   标准  

摘要： 特种设备定期检验中,无损检测是其最重要的部分。对某电厂再热蒸汽管道进行超声检测时,对同一缺陷采用不同标准检测导致评定结果不同。本文对比标准NB/T 47013.3—2015与JB/T 4730.3—2005中灵敏度规定,通过试验研究超声检测分别采用CSK-IIA-1试块与CSK-IIIA试块的灵敏度。实验研究和现场检测结果表明,壁厚范围6~40 mm,管径≥500 mm的管道焊接接头采用CSK-IIA-1试块的灵敏度要高于CSK-IIIA试块。

关键词： 电力通信   同步数字体系(SDH)   光纤传输网   网络建设  

摘要： 同步数字体系(Synchronous Digital Hierarchy,SDH)光纤传输网在电力通信中扮演着至关重要的角色。光纤传输网凭借其高带宽、大容量以及高可靠性的特性,已成为电力通信的骨干网络技术。该技术支持电力系统的远程控制、实时监测以及灾难恢复等关键功能,显著提高了电力系统的运行效率和服务质量。通过分析SDH技术的基本概念、建设流程及其在电力通信中的应用,揭示SDH光纤传输网对于电力系统稳定运行的重要贡献,并对其未来发展趋势进行展望。