摘要：Anisotanols A—D(1-4),four new compounds possessing an unprecedented sesquiterpenoid skeleton with a congested tricyclic 6/3/5 ring system,were obtained from Anisodus *** structures were elucidated by comprehensive spectroscopic techniques,and the absolute configurations were confirmed via ECD calculations and single-crystal X-ray diffractions.A putative biosynthetic pathway for these compounds was *** evaluation disclosed that compound 3 showed anti-angiogenic activity by inhibiting the viability,migration,and tube formation in HUVECs.

摘要：近年来,我国尾矿库重特大事故时有发生,给社会及人民生命财产造成了极大威胁和损害,为了满足尾矿库的安全运行,从源头上杜绝重特大事故的发生,按国家相关规范、规程的规定对尾矿堆积坝进行岩土工程勘察是稳定性分析与评价关健。从岩土工程勘察技术在尾矿堆积坝勘察中应用进行了探讨,为尾矿堆积坝勘察提供可借鉴工程经验。

摘要：Very high frequency(VHF) photocathode guns have excellent performance and are being increasingly selected as electron sources for high-repetition-rate X-ray free-electron lasers. As a highly loaded quality factor cavity, the VHF gun requires high stability in the amplitude and phase of the cavity field. However, the gun is microwave powered by two solid-state power sources through two separate power couplers. The input difference between the two power couplers will influence the stability of the cavity field. To systematically study this influence and obtain measurement formulae, a multi-port VHF gun LCR circuit model is built and analyzed. During the warm-up condition, the cavity structure will be deformed due to the large-scale change in the cavity temperature. Then, the deformation will result in cavity resonant frequency changes. To prevent the mechanic tuner from suffering damages due to the frequent and long-distance movement for correcting the cavity resonant frequency, a self-excited loop(SEL) control system is considered for changing the loop phase and make the loop frequency follow the resonant frequency. In this study, a steady-state model of the VHF gun cavity is built for obtaining the optimal input coupler coefficient and the stability requirement of the forward voltage. Then, the generator-driven resonator and SEL control system, which combine with the VHF multiport modeling, are modeled and simulated. The simulated results show that the SEL system can perfectly operate in the process of condition and warm-up.

摘要：A front-end electronics of dose monitor has been developed for measuring irradiation dose to the patient in Shanghai Advanced Proton Therapy *** parallel plate ionization chamber is used for the dose *** the traditional method of recycling capacitor integration and voltage-to-frequency conversion,this dose monitor electronics uses the trans-impedance amplifier and analog-to-digital conversion *** performs satisfactorily,with the integral nonlinearity of less than ±0.04 nA in the range of-400 to 50 nA and the resolution of about±0.6 nA.

摘要：为降低综合能耗,在构建RSV乙烷回收模拟流程的基础上,通过Plackett-Burman设计完成关键参数的分析和筛选,通过ELM模型实现输入与输出参数之间的非线性映射,最后基于改进哈里斯鹰(IHHO)算法实现ELM模型的优化及最优工艺参数的求解。结果表明,原料气流量、脱甲烷塔压、原料气温度、干气回流比、低温分离器气相分流比、低温分离器温度和膨胀机出口压力等因素对综合能耗的影响较大,应纳入ELM模型数据库作为输入变量;对于综合能耗的预测,IHHO-ELM模型在训练集、验证集和测试集上的相关系数分别为0.9921、0.9876、0.9855,预测效果最优;参数优化后,乙烷收率降低了2.38%,液化石油气和稳定轻烃的产品指标变化不大,综合能耗可减少23.62%。

摘要：A novel type of molecular tweezer receptors based on deoxycholic acid has been designed and synthesized and their binding properties were examined by UV-vis spectral titration. These molecular tweezers showed a high selectivity toward F^- over Cl^-, Br^-, I^-, AcO^-, H2PO4^-.

摘要：在过去百余年中,汽车声音的角色和作用经历了错综复杂的演变,其中的思维和脉络将对认识现代汽车声音及其设计起到重要的启迪作用。本文将通过对汽车声音的角色作用、发展历史和涉众行动的梳理与分析,总结汽车声音演变的线索和逻辑,希望助力于汽车声音的实际应用设计和理论研究探索。

摘要：在平原型水库反推入库流量过程中,存在明显的噪声干扰,导致传统的洪水预报方法精度下降。对此,提出一种结合卷积神经网络(CNN)与双向长短期记忆神经网络(BiLSTM)的入库洪水预报模型,该模型采用CNN的卷积层挖掘入库洪水数据中的深层特征信息,并赋予不重要特征较低的权重,以便模型更加专注于对目标任务关键的特征信息。此外,利用BiLSTM处理流量序列中的长期依赖问题,通过其遗忘门有选择性地过滤掉权重较低的特征信息,实现对入库洪水过程的准确预测。最后,基于不同预见期评估所构建模型在安徽省合肥市大房郢水库入库洪水预报中的精准度。结果表明,4 h预见期下CNN-BiLSTM模型在入库洪水预报中具有更高的预报精度,相比BiLSTM模型和新安江(XAJ)模型,其确定性系数(D_(DC))分别提升9.9%、39.0%,均方根误差(R_(RMSE))和相对偏差(B_(BIAS))分别降低34.6%、17.1%和148.6%、20.6%。研究成果可为反推入库流量过程的平原型水库入库洪水预报提供新思路和技术支持。

摘要：基于三峡和葛洲坝电站2018年实测水位、流量数据和一维解析模型,重点讨论了梯级电站调峰驱动的洪水波在两坝间河道的传播过程。在三峡和葛洲坝同时进行日调峰的背景下,2个电站的出库流量均呈显著的日波动和半日波动现象,两电站的流量日波动幅度平均分别在1500~2000 m^(3)/s和1200~1500 m^(3)/s之间,黄陵庙和南津关两个水位站的水位日波动幅度均在0.5~0.8 m之间。基于一维解析模型能够很好地模拟和再现两坝间河道的水位和流量波动过程。模型模拟结果分析表明,两坝间河道洪水波以周期为1.2 h的高频驻波进行传播,驻波的最大水位和流量振幅分别约为2.1 cm和210 m^(3)/s。该洪水波是由两个电站调峰流量共同驱动和叠加生成的,下游葛洲坝电站调峰时间对河道洪水波有显著影响,若将调峰时间由现行的0.6 h调整到1.2 h,洪水波振幅将显著增强。河道底摩擦因数对洪水波生成时的波高影响较小,但会影响洪水波在传播过程中的衰减速度。

摘要：For generating a uniform and steady magnetic field, Helmholtz coil is extensively used in nuclear magnetic resonance gyro(NMRG). Unfortunately, the volume of Helmholtz coil makes it inconvenient to miniaturize NMRG. This study introduces Braunbeck coil that can be used in magnetic field excitation system. Braunbeck coil can produce homogeneous magnetic field within a limit space, and occupy a small volume. In addition, this study presents mathematical expressions that can be used to calculate the area of uniform magnetic field. Experimental test verifies the effectiveness of the proposed design, and the results accord closely with the actual simulation.