新型M-THGEM结构探测器的蒙特卡罗模拟研究

新型多层厚型气体电子倍增器（Multi-layers THick Gas Electron Multiplier,M-THGEM）和传统THGEM （厚型气体电子倍增器）相比,具有连续的雪崩区,能够在低气压和低电压下都有较高增益,结构更紧凑,易于大面积制作等优势。对M-THGEM探测器的工作原理及性能进行了模拟研究,首先通过有限元（ANSYS）软件对二层与三层结构的M-THGEM进行了建模,对电场和电势分布分别进行了模拟计算;再利用Garfield++程序包对M-THGEM探测器在不同低气压和不同工作电压下的增益、感生信号、正离子反馈率等性能进行了研究。模拟结果表明,三层结构M-THGEM在低气压（200 Torr）、纯He气体条件下,能够获得较稳定的增益（105）,输出信号的宽度在12 ns左右;同时,为降低正离子反馈率,本工作提出并研究了一种非对称的电压施加方式,结果表明,这种施加方式能有效降低正离子的反馈率。Compared to THGEM (Thick Gas Electron Multiplier), the novel Multilayer Thick Gaseous Electron Multiplier (M-THGEM) has many advantages, such as continuous avalanche zone, more compact structure, high gain at low pressure and low operating voltage, and easy to make large-area production. In the presented work, two types of the M-THGEM detector (two or three layers) were modeled, and their main principle and performances were also studied by simulation. Two types of the detector were molded and simulated by using the finite element software (ANSYS), and the electric field distribution and nodes information lists were figured out. The effective gain and induced signal from M-THGEM detector at different gas pressures and operating voltages were studied with the Garfield++ package. The simulation results shown that M-THGEM can obtain a stable higher gain around 105 in an environment where has a low pressure even in 200 Torr and within a pure inertia gas such as He. At this condition, the width of the induced signal from the three-layers structure is around 120 ns. Additionally, an asymmetric way of the applied voltage was studied and aim to reduce the efficiency of ion feedback, and our results show that this method is effective.     

充水阻抗管中测量材料声学性能的校准方法研究

提出了一种在充水阻抗管中,应用传递函数测量材料声学性能的三参数校准方法。在双传感器传递函数法的基础上,考虑充水阻抗管中水听器间不一致性和管内结构对声场局部扰动等因素的校准,导出了三个综合的无量纲校准参数。通过改变充水阻抗管中测量面的三个已知反射系数,测量出对应的三个传递函数,可以求出这三个校准参数。在充水阻抗管中分别对水/空气界面和一种水声材料进行了测量试验,应用该方法对测量结果的进行了校准,并对校准前后的结果进行了分析比较。      

铬、钕双掺钆镓石榴石(Cr~(4+),Nd~(3+))∶Gd_3Ga_5O_(12)激光晶体光学性能的研究

用提拉法生长了掺铬、钕的钆镓石榴石(Cr4+,Nd3+∶GGG)自调Q激光晶体。报道了室温下的吸收光谱和荧光光谱特性。分析了Cr离子浓度对光谱性质的影响。比较了Cr4+∶GGG,Nd3+∶GGG和(Cr4+,Nd3+)∶GGG晶体吸收光谱的关系。测量了(Cr4+,Nd3+)∶GGG晶体和Nd3+∶GGG晶体的荧光寿命,它们分别是33μs和250μs。实验表明,(Cr4+,Nd3+)∶GGG晶体是一种非常有潜力的自调Q激光晶体,可以实现大功率激光器的小型化和全固态化。     

管道有源噪声控制中壁面分布次级声源的空间分布优化

为了改进管道中高阶模式声波的有源控制效果,研究了壁面分布次级声源的空间分布优化问题。首先提出管道中次级声源独立控制高阶模式声波的理论模型。然后推导次级声源在管道中各方向上空间分布对控制高阶模式声波的贡献,得到了次级声源空间分布的优化准则。通过将空间分布离散化,采用最小化管道中声能流的控制策略得到次级声源的最优驱动强度。最后通过数值仿真对比最优驱动强度时各种次级声源空间分布对控制性能的影响,验证了通过优化次级声源空间分布能显著提高控制效果。仿真结果表明,当次级声源分布于管道所有壁面且沿管道轴向分布范围较大时,高阶模式的控制效率最高。     

HIF in Gastric Cancer: Regulation and Therapeutic Target

HIF means hypoxia-inducible factor gene family, and it could regulate various biological processes, including tumor development. In 2021, the FDA approved the new drug Welireg for targeting HIF-2a, and it is mainly used to treat von Hippel-Lindau syndrome, which demonstrated its good prospects in tumor therapy. As the fourth deadliest cancer worldwide, gastric cancer endangers the health of people all across the world. Currently, there are various treatment methods for patients with gastric cancer, but the five-year survival rate of patients with advanced gastric cancer is still not high. Therefore, here we reviewed the regulatory role and target role of HIF in gastric cancer, and provided some references for the treatment of gastric cancer.     

用于自适应波束形成语音增强的球谐域掩蔽函数估计方法

提出一种用于球形阵列自适应波束形成的掩蔽函数估计方法.该方法利用包含空间信息的球谐系数提取低维空间向量,并采用复高斯混合模型和深度学习两种方案来估计掩蔽函数,最终利用估计的掩蔽函数设计最小方差无失真响应波束形成器,以达到空域滤波的效果.理论分析和仿真实验证明,对于相同时长的声信号,球谐域掩蔽函数估计方法的计算复杂度比传...     

Prescribed performance slide mode guidance law with terminal line-of-sight angle constraint against maneuvering targets

Nonlinear Dynamics - This paper proposes a new terminal homing guidance law with line-of-sight angle constraint for a missile to intercept a noncooperative maneuvering target by integrating...