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1. chinaXiv:202305.00003 [pdf]

Large-Bandwidth High-Gain Low-Noise Transimpedance Amplifier for Scanning Tunneling Microscope

Ying-Xin Liang
Subjects: Electronics and Communication Technology >> Electron Technology
Subjects: Engineering and technical science >> Physics Related Engineering and Technology
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology
Subjects: Engineering and technical science >> Technology of Instrument and Meter

In this work, a design of large-bandwidth high-gain low-noise transimpedance amplifier (TIA) for scanning tunneling microscope (STM) is proposed. The simulations show that the proposed TIA has the bandwidth higher than 200 kHz, two orders of magnitude higher than those of conventional commercial TIAs for STM. At low frequencies, the noises of the proposed TIA are almost the same as the conventional commercial ones with the same transimpedance gain. At high frequencies, its calculated input equivalent noise voltage power spectral density (PSD) is 40 (nV)2/Hz and its input equivalent noise current PSD is 3.2 (fA)2/Hz at 10 kHz. The corresponding values are 23 (nV)2/Hz and 88 (fA)2/Hz at 100 kHz. The STM with the proposed TIA can meet the needs of fast high-quality STM imaging measurements and fast high-energy-resolution scanning tunneling spectra measurements for the low-conducting materials, such as complex organic systems and wide bandgap semiconductors.

submitted time 2023-05-01 Hits462Downloads101 Comment 0

2. chinaXiv:202305.00002 [pdf]

Ultra-low-noise transimpedance amplifier in cryogenic STM for studying novel quantum states by measuring shot noise

Ying-xin Liang
Subjects: Engineering and technical science >> Physics Related Engineering and Technology
Subjects: Engineering and technical science >> Technology of Instrument and Meter
Subjects: Electronics and Communication Technology >> Electron Technology
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology

An ultra-low-noise large-bandwidth transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. The TIA connected with the tip-sample component in CryoSTM is called as CryoSTM-TIA. Its transimpedance gain is as high as 1 GΩ, and its bandwidth is over 300 kHz, but its equivalent input noise current power spectral density is less than 4 (fA)2/Hz at 100 kHz. The low inherent noise for the CryoSTM-TIA is due to its special design: (1) its pre-amplifier is made of a pair of low-noise cryogenic high electron mobility transistors (HEMTs); (2) the noise generated by one HEMT is eliminated by a large capacitor; (3) the capacitance of the cable connected the gate of the other HEMT to the tip is minimized; (4) thermal noise sources, such as the feedback resistor, are placed in the cryogenic zone. The dc output voltage drift of the CryoSTM-TIA is very low, as 5 μV/°C. The apparatus can be used for measuring the scanning tunneling differential conductance spectra, especially the scanning tunneling shot noise spectra (STSNS) of quantum systems, even if the shot noise is very low. It provides a universal tool to study various novel quantum states by measuring STSNS, such as detecting the Majorana bound states.

submitted time 2023-05-01 Hits455Downloads101 Comment 0

3. chinaXiv:202212.00180 [pdf]

Low-noise high-gain large-bandwidth transimpedance ampli?er with cascode-type preamplifier for cryogenic STM

梁迎新
Comment:已发表在Journal of Low Temperature Physics
Subjects: Engineering and technical science >> Physics Related Engineering and Technology
Subjects: Engineering and technical science >> Technology of Instrument and Meter
Subjects: Electronics and Communication Technology >> Electron Technology
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology

提出了一种用于低温扫描隧道显微镜(CryoSTM)的低噪声高增益大带宽跨阻放大器(TIA)。在CryoSTM中与尖端样品组件连接的TIA称为CryoSTM-TIA。CryoSTM-TIA的跨阻增益为10Gohm,带宽超过100kHz,在100kHz时等效输入噪声电流功率谱密度小于4(fA)2/Hz。CryoSTM-TIA的低固有噪声是由于其特殊的设计: (1)其前置放大器(Pre-Amp)由低噪声低温高电子迁移率晶体管制成; (2)前置放大器采用卡片式配置,避免米勒效应,降低输入电容CA; (3)将前置放大器输入端连接到尖端的电缆的电容,即CI最小化; (4)热噪声源,如反馈电阻,放置在低温区。由于在反馈回路中应用了频率补偿,减小了CA,减小了CI,实现了高增益和大带宽。该仪器可用于低电导率材料扫描隧道光谱的快速高能量分辨率测量,特别是用于测量其扫描隧道发射噪声谱。

submitted time 2022-12-29 Hits2104Downloads289 Comment 0

4. chinaXiv:202212.00178 [pdf]

Ultra-low-noise transimpedance amplifier with a single HEMT in pre-amplifier for measuring shot noise in cryogenic STM

梁迎新
Comment:改论文被期刊要求做major revision。由于做major revision需要较长时间,作者希望大家能够知晓该论文中的电路设计和电路装置的特殊用途曾在该论文中被提出过。
Subjects: Engineering and technical science >> Physics Related Engineering and Technology
Subjects: Engineering and technical science >> Technology of Instrument and Meter
Subjects: Electronics and Communication Technology >> Electron Technology
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology

本文提出了一种用于低温扫描隧道显微镜(CryoSTM)的跨阻放大器(TIA)设计方案。在CryoSTM中带有尖端样品成分的TIA称为CryoSTM-TIA。该CryoSTM-TIA的跨阻增益在1Gohm,而其带宽大于300kHz。所提出的CryoSTM-TIA的独特特点是其前置放大器由单个低温高电子迁移率晶体管(HEMT)制成,因此在100kHz时仪器等效输入噪声电流功率谱密度低于4(fA)2/Hz。此外,应用“偏置冷却法”可用于原位控制HEMT掺杂区冻结DX-中心的密度,改变其结构以降低器件噪声。利用该仪器,可以进行高能量分辨率的快速扫描隧道光谱测量。并且,它能够测量各种量子系统在原子尺度上的扫描隧道散粒噪声谱(STSNS),即使散粒噪声非常低。它为通过测量STSNS来研究新的量子态提供了一个强大的工具,例如检测拓扑量子系统中马约拉纳束缚态的存在。

submitted time 2022-12-29 Hits647Downloads296 Comment 0

5. chinaXiv:202206.00126 [pdf]

Low-Noise Large-Bandwidth Transimpedance Amplifier for Measuring Scanning Tunneling Shot Noise Spectra in Cryogenic STM and its Applications

梁迎新
Comment:已发表在Ultramicroscopy 234, 113466 (2022)
Subjects: Engineering and technical science >> Physics Related Engineering and Technology
Subjects: Engineering and technical science >> Technology of Instrument and Meter
Subjects: Electronics and Communication Technology >> Electron Technology
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology

散粒噪声是一个研究量子体系的强有力的手段。本文提出一种用于低温扫描隧道显微镜 (CryoSTM)的跨阻放大器(TIA),可满足散粒噪声测量的需要。在该TIA中,前置放大器(Pre-Amp)由超低噪声低功率低温高电子迁移率晶体管(HEMTs)构成。以1Gohm的高跨阻增益,所设计的TIA的带宽超过300 kHz。在CryoSTM中,这个TIA连同针尖-样品组件和输入信号被称为CryoSTM-TIA。它的带宽仍然超过300kHz,并且它的等效输入噪声电流功率谱密度在100 kHz小于30 (fA)2/Hz。该CryoSTM-TIA能够用于测量扫描隧道电流谱和扫描隧道微分电导谱。本文又特别阐述了如何用该CryoSTM-TIA测量量子体系的扫描隧道噪声电流功率谱和散粒噪声谱。这就使得用低温CryoSTM-TIA通过测量散粒噪声来研究各种量子体系中的新奇量子现象成为可能,例如在局域尺度中的Andreev反射、在单分子磁体中的Kondo效应,等等。特别是把它用于研究与实现拓扑量子计算有关的Majorana零能模的存在性。

submitted time 2022-12-29 Hits1253Downloads526 Comment 0

6. chinaXiv:202210.00180 [pdf]

一种离子液体添加剂在可印刷介观钙钛矿太阳能电池中的 阴阳离子协同策略

佘 斌; 王栋杰; 张 坚
Subjects: Electronics and Communication Technology >> Other Disciplines of Electronics and Communication Technology

为了提升可印刷介观钙钛矿太阳能电池(MPSCs)的器件性能及长期稳定性,提出了一种阴阳离子协同策略,即将
离子液体添加剂1-乙基-3-甲基咪唑醋酸盐(EMIMAC)引入钙钛矿活性层中并用于制备高效稳定的MPSCs。实验结果表
明,咪唑离子(EMIM+ )通过配位效应实现了离子态缺陷钝化(如Pb2+ 和PbI3- ),促进了钙钛矿结晶。另一方面,醋酸根离
子(AC- )与TiO2 的配位同时钝化了TiO2 表面上的氧空位缺陷,从而改善了TiO2/钙钛矿界面的界面接触。因此,
EMIMAC中EMIM+ 离子和AC- 离子的协同效应实现了更好的钙钛矿结晶度、更有效的电荷传输和更低的非辐射复合。
最终,MPSCs的能量转换效率(PCE)从13.83%提高到15.48%,且滞后可忽略不计。此外,未封装的MPSCs暴露于空气
中(RH=50±5%)60 d后仍保持初始PCE的90%,表现出优异的长期稳定性。实验结果表明,离子液体添加剂EMIMAC
可以有效提升器件的PCE和稳定性,为进一步改善器件性能提供了一种有效策略。

submitted time 2022-10-21 Cooperative journals:《桂林电子科技大学学报》 Hits409Downloads170 Comment 0

7. chinaXiv:202206.00073 [pdf]

无线传感器网络数据分发中节点克隆攻击检测方案

张倩; 陈宏滨
Subjects: Electronics and Communication Technology >> Information Processing

无线传感器网络(WSNs)中,数据分发是一种重要的传输方式,需要满足以下要求:可靠性,节能和可扩展性。然而,现有的研究工作很少关注数据分发中所存在的攻击,导致数据分发的可靠性大打折扣。为了检测出WSNs数据分发中的节点克隆攻击,保证数据分发的高可靠性,提出了基于单轮零知识证明的节点克隆攻击检测方案。本方案通过构建析取-叠加码生成专属于各个节点的数字指纹,在单轮零知识证明方案中对节点的数字指纹进行验证,可以检测出没有正确数字指纹的克隆节点。仿真表明使用提出的检测方案,可以保证WSNs在数据分发过程中的高可靠性.

In wireless sensor networks (WSNs), data dissemination is an essential transmission mode, which needs to meet three requirements: reliability, energy saving and scalability. Existing research pays little attention to the attacks in data dissemination, resulting in a significant loss of the reliability of data dissemination. In order to detect node clone attacks in WSNs data dissemination and ensure high reliability of data dissemination, a node clone attack detection scheme based on single round zero knowledge proof is proposed. In this scheme, the digital fingerprint of each node is generated by constructing superimposed disjunct code, and the cloned node without correct digital fingerprint can be detected by verifying the digital fingerprint of the node in the single round zero-knowledge proof scheme. Simulation results show that the proposed scheme can ensure the high reliability of WSNs in the data dissemination process.

submitted time 2022-06-07 Cooperative journals:《桂林电子科技大学学报》 Hits1327Downloads415 Comment 0

8. chinaXiv:202202.00011 [pdf]

Exact Decomposition of Multifrequency Discrete Real and Complex Signals

刘保国
Subjects: Electronics and Communication Technology >> Information Processing
Subjects: Engineering and technical science >> Engineering General Technology
Subjects: Mechanical Engineering >> Other Disciplines of Mechanical Engineering

‘The spectral leakage (SL) from windowing and the picket fence effect (PEF) from discretization’ have been among the standard contents in textbooks for many decades. The SL and PEF would cause the distortions in amplitude, frequency, and phase of signals, which have always been of concern, and attempts have been made to solve them. This paper proposes two novel decomposition theorems that can totally eliminate the SL and PEF, they could broaden the knowledge of signal processing. First, two generalized eigenvalue equations are constructed for multifrequency discrete real signals and complex signals. The two decomposition theorems are then proved. On these bases, exact decomposition methods for real and complex signals are proposed. For a noise-free multifrequency real signal with m sinusoidal components, the frequency, amplitude, and phase of each component can be exactly calculated by using just 4m–1 discrete values and its second-order derivatives. For a multifrequency complex signal, only 2m–1 discrete values and its first-order derivatives are needed. The numerical experiments show that the proposed methods have very high resolution, and the sampling rate does not necessarily obey the Nyquist sampling theorem. With noisy signals, the proposed methods have extraordinary accuracy.

submitted time 2022-02-08 Hits6061Downloads978 Comment 0

9. chinaXiv:202109.00021 [pdf]

一种基于地球同步卫星光学遥感影像的运动船舶检测与跟踪方法

余伟
Subjects: Electronics and Communication Technology >> Information Processing

地球静止光学遥感卫星具有时间分辨率高、覆盖范围广等优点,可以大范围连续跟踪观察海上船舶目标。然而,地球同步卫星遥感影像中的船舶目标通常体积小、强度弱,易受云、岛等因素影响,给船舶目标的检测带来很大的困难。本文提出了一种从地球静止光学遥感图像中检测在海面上移动的船舶的新方法:首先,采用自适应非线性灰度拉伸(ANGS)方法对图像进行增强,以突出小而弱的船舶目标。其次,设计了一种多尺度双邻域差分对比度测量(MDDCM)方法来检测候选船舶目标的位置。然后,分析每个候选区域的形状特征以去除虚假的船舶目标。最后,联合概率数据关联(JPDA)方法用于多帧数据关联和跟踪。实验表明,该方法能够有效地检测和跟踪GF-4卫星光学遥感影像中的运动船舶目标,与其他经典方法相比,该方法具有更好的检测性能。

submitted time 2021-09-10 Hits3302Downloads1169 Comment 0

10. chinaXiv:202009.00016 [pdf]

基于单脉冲雷达和差通道多普勒估计的前视成像

李悦丽; 马萌恩; 赵崇辉
Subjects: Electronics and Communication Technology >> Radar Engineering

单脉冲测角技术用于扫描雷达前视成像可有效提高图像的清晰度,但单个脉冲对同分辨单元多目标测角时会发生角闪烁现象,造成图像模糊。本文提出了一种基于单脉冲雷达和差通道多普勒估计的前视成像算法,利用目标和平台之间相对运动引起的多普勒梯度差异实现同分辨单元内不同方向目标的分离,然后在多普勒域采用和差比幅测角技术测量目标的方位角,完成能量投影。为提高测角精度,进一步提出了采用调频Z变换(Chirp Z Transform)重建和差多普勒估计并进行比幅测角的算法。点目标仿真实验结果表明,所提出的算法在前斜视方向具有分离多目标的能力,对实测数据成像结果验证了基于CZT的成像算法相比传统算法能显著提高对场景成像的轮廓清晰度。

submitted time 2020-09-08 Hits5490Downloads1754 Comment 0

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