具有增益均衡功能的新型宽带MMIC放大器

由于行波管"山丘状"功率增益特性需要补偿,提出了具有增益均衡功能的新型宽带单片放大器结构。利用FET作可调元件的嵌入式低损无源滤波网络实现了增益均衡功能。设计中采用了有别于传统的分布放大器形式,选择了高效率高增益级联型单级分布放大器结构。研制出的嵌入增益均衡滤波网络的三级级联型单级分布放大器,在6～14GHz频带范围内,仅使用5个0.25×120μmp HEMT,小信号增益15.5±1.3dB;输入输出反射损耗<-10dB;NF<8dB;频带中部引入的电调衰减幅度超过7dB。芯片面积为2.48mm×1.25mm。验证了此新型电路结构的可行性。     

Ka频段6 W固态集成功放的热分析与设计

热模拟是毫米波中高功率放大器设计中的关键环节之一,可靠的散热结构可确保系统中有源器件工作在额定温度下,而基于有限元方法的数值模拟技术是毫米波功率放大器热分析的重要工具。针对由四块毫米波功率单片合成的Ka频段6 W固态集成功放,采用有限元软件ANSYS建立了其三维热模型,对模型在空气自然对流情况下的温度分布状况进行了模拟和分析,模拟结果与实测值基本吻合,验证了模型的有效性。研究结果对毫米波功率放大器的热设计提供了重要的理论依据。     

基于AD603程控增益大功率宽带直流放大器的设计

采用低噪声增益可程控集成运算放大器AD603和高频三极管2N2219和2N2905等器件设计了宽带直流放大器,该放大器具有增益可程控、功率高、频带宽、带宽可选择等特点。输入级采用两级AD603级联,以提高增益控制范围;中间级采用分立元件制作了高输出功率放大器,输出级设计了两路通频带分别为0～5MHz以及0～10MHz的低通滤波器实现带宽的可预置,通过51单片机可以对放大器增益和带宽进行控制。此外对提高直流放大器的各种性能指标提出了多种具体措施,在自动化要求较高的系统中具有很好的实用性。     

Multichannel Sonocatalysis Amplifiers Target IDH1-Mutated Tumor Plasticity and Attenuate Ros Tolerance to Repress Malignant Cholangiocarcinoma

Tumor adaptation-originated tumor tolerance that compensatory mechanisms (e.g., isocitrate dehydrogenase (IDH) mutation) jointly shape is the dominant obstacle of ROS therapy. Currently, targeting a single pathway fails to fundamentally reverse the complex milieu and diminish tumor adaptation. Herein, a multichannel sonocatalysis amplifier is engineered via one-pot gas diffusion method to attenuate IDH1-mutated cholangiocarcinoma plasticity and tolerance to ROS therapy, wherein triptolide and IR780 are co-loaded in DSPE-mPEG-modified CaCO₃ nanoparticles. Triptolide can blockade Nrf2 to cut off glutathione biosynthesis via blockading proteomic communication, and disrupt redox homeostasis to potentiate IR780-mediated sonocatalytic ROS production. ROS-induced mitochondria damages disrupt Ca²⁺ homeostasis and in turn aggravate ROS accumulation, which cooperates with sonocatalysis and Nrf2 blockade to reprogram mitochondrial energy and substance metabolism (e.g., adenosine triphosphatase and glutathione), hinder DNA self-repair, and impair IDH1-mutation-asired tolerance. Systematic experiments support that these actions in such multichannel sonocatalysis amplifiers indeed disrupt Ca²⁺/redox homeostasis to disarm robust tumor plasticity and IDH1-mutation-induced tolerance to sonocatalysis therapy against IDH1-mutated cholangiocarcinoma progression. Briefly, the sonocatalysis amplifiers pave a comprehensive avenue to reprogram tumor metabolism, target tumor vulnerability, and attenuate tumor plasticity against genomic instability-raised treatment adaptation.     

基于长周期光纤光栅的增益均衡器设计

运用耦合模理论,通过对长周期光纤光栅形成的光纤中导模和包层模耦合的分析计算,设计了一个由三个长周期光纤光栅组成的掺铒光纤放大器的增益平坦滤波器。针对掺铒光纤放大器的一个典型增益曲线,这一滤波器可实现33nm带宽内小于0．3dB的增益平坦,而且所选取的基准增益得到保留,基准增益对应的增益带宽损失很小。