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 submitted time 2024-05-06
Abstract: In this work, a design of transimpedance amplifier (TIA) for cryogenic scanning tunneling microscope (CryoSTM) is proposed. The TIA with the tip-sample component in CryoSTM is called as CryoSTM-TIA. With transimpedance gain of 1 Gohm, the bandwidth of the CryoSTM-TIA is larger than 200 kHz. The distinctive feature of the proposed CryoSTM-TIA is that its pre-amplifier is made of a single cryogenic high electron mobility transistor (HEMT), so the apparatus equivalent input noise current power spectral density at 100 kHz is lower than 6 (fA)2/Hz. In addition, bias-cooling method can be used to in-situ control the density of the frozen DX- centers in the HEMT doping area, changing its structure to reduce the device noises. With this apparatus, fast scanning tunneling spectra measurements with high-energy-resolution are capable to be performed. And, it is capable to measure scanning tunneling shot noise spectra (STSNS) at the atomic scale for various quantum systems, even if the shot noise is very low. It provides a powerful tool to investigate novel quantum states by measuring STSNS, such as detecting the existence of Majorana bound states in the topological quantum systems.
Peer Review Status:Awaiting Review
Subjects: Electronics and Communication Technology >> Electron Technology Subjects: Engineering and technical science >> Technology of Instrument and Meter Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology Subjects: Physics >> Condensed Matter: Electronic Structure, Electrical, Magnetic, and Optical Properties submitted time 2024-05-06
Abstract: In this work, we design and fabricate the transimpedance Amplifier (TIA) following the design mentioned in Ref. 1 . In the TIA, the preamplifier (Pre-Amp) is made of a junction field effect transistor (JFET) that can work at 77 K. The post-amplifier (Post-Amp) is made of an operational amplifier. Cascade Pre-Amp and Post-Amp to form the inverting-amplifier. With a 1.13 Gohm feedback network, the gain of TIA is 1.13 Gohm and its bandwidth is about 97 kHz. The equivalent input noise voltage power spectral density of TIA is not more than 9 (nV)2/Hz at 10 kHz and 4 (nV)2/Hz at 50kHz, and its equivalent input noise current power spectral density is about 26 (fA)2/Hz at 10 kHz and 240 (fA)2/Hz at 50 kHz. The measured transport performances and noise performances of TIA are consistent with the simulations and calculations. As an example, the realization of TIA in this work verifies the design method and analytical calculations for the low-noise large-bandwidth high-gain TIA proposed in Ref. 1,2 . And, the TIA in this work is perfect for the cryogenic STM working at liquid nitrogen temperature.
Peer Review Status:Awaiting Review
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2024-03-23
Abstract: To predict the fractal decoded image quality more efficiently, an accumulated collage error coefficient (ACEC) based method was proposed in this study. Firstly, the definition of ACEC was introduced to describe the relationship among the upper bound, lower bound, and actual value of the accumulated collage error of all range blocks. Moreover, the definition and monotonicity of the relative error of ACEC were also defined and discussed. While the relative error of ACEC reaches a relatively small value, the average collage error (ACER) can be estimated approximately, and then the encoding process can be terminated to directly predict the peak signal-to-noise ratio (PSNR) quality of decoded images. Experimental results show that compared with the previous method, the proposed method can predict the decoded image quality more accurately with fewer computations.
Peer Review Status:Awaiting Review
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology Subjects: Materials Science >> Ceramics submitted time 2024-03-20
Abstract: The long-term structural stability of high-level radioactive wastes was the key for deep geological disposal under irradiation. In this work, 500 keV He2+ ion beams irradiation of zirconolite-2M, zirconolite-3O and zirconolite-4M three-type solid solutions were performed to study the structure damage from α decay in long-term deep geological disposal. All samples were synthesized through conventional high-temperature solid-state reaction at 1400℃ sintered twice 48h. The grazing incidence x-ray diffraction (GIXRD), Raman and x-ray photoelectron spectroscopy (XPS) results indicated that zirconlite-2M sample experienced crystalline phase evolution from zirconolite-2M to zirconolite-4M to disorder pyrochlore and amorphous with irradiation dose increased. For zirconolite-3O sample, the phase transformed to perovskite at 5×1015 ions/cm2 dose, and perovskite quickly transformed to disorder pyrochlore at higher dose. Disorder pyrochlore became major crystal structure when dose increased to 1×1017 ions/cm2. Zirconolite-4M remained with disorder pyrochlore or defect fluorite second phase under 1×1017 ions/cm2 irradiation. Summarily, the irradiation damage resistance of zirconolite-2M was similar with zirconolite-3O, and lower than zirconolite-4M.
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2024-02-27
Abstract: The energy storage and conversion found in ferroelectrics realize through polar domain and domain wall microstructures resulted in complex polar topologies or within transformations from macro/micro domain to nano domain. The physical models are adopted with basic domains and domain walls including 90o, 180o, 71o and 109o classified into two categories of 180o and α-angle, and are reconstructed with equivalent circuits simplified according to the reported patterns. Although electrical energy is known to be maintained by the balance of charging and loss, the effect of circuits on microstructure has been rarely explored because of the relative paucity of patterns implemented experimentally for domain and domain wall. And here the diagrammatic sketches of vortex pattern and transformation into nano domain are designed and derived into their respective formulas of total capacitance and energy density with crucial structural features. The findings reveal novel mechanisms on energy storage by microstructures that can be used to propose effective creation strategies even in designing modern measure equipment.
Peer Review Status:Awaiting Review
Subjects: Psychology >> Cognitive Psychology Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology Subjects: Medicine, Pharmacy >> Preclinical Medicine submitted time 2024-01-21
Abstract: The non-exclusive dual-process working model proposed in De Neys’ article effectively makes up for the shortcomings of the existing theories and models, but the explanation of the switching problem and the exclusivity problem in this article cannot constitute a complete rejection of the existing switching mechanism and the traditional fast-slow dual-process model. We believe that a more powerful and logical way of explaining the theory is as follows: human reasoning process is related to the complexity of the problem being faced, and it is also closely related to the reading process of the problem; in the process of reading the problem, the brain will automatically choose different ways of reasoning for the problem of different levels of complexity; and in the process of selection, the principle of minimum energy should still be valid.
Peer Review Status:Awaiting Review
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2024-01-17
Abstract: A 20-kiloton liquid scintillator detector is designed in the Jiangmen Underground Neutrino Observatory (JUNO) for multiple physics purposes, including the determination of the neutrino mass ordering through reactor neutrinos, as well as measuring supernova neutrinos, solar neutrinos, and atmosphere neutrinos to explore different physics topics. Efficient reconstruction algorithms are needed to achieve these physics goals in a wide energy range from MeV to GeV. In this paper, we present a novel method for reconstructing the energy of events using hit information from 3-inch photomultiplier tubes (PMTs) and the OCCUPANCY method. Our algorithm exhibits good performance in accurate energy reconstruction, validated with electron Monte Carlo samples spanning kinetic energies from 10~MeV to 1~GeV.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2024-01-10
Abstract: Traditional particle identification methods are time consuming, experience-dependent, and poor repeatability challenges in heavy-ion collisions at low and intermediate energies. Researchers urgently need solutions to the dilemma of traditional particle identification methods. This study explores the possibility of applying intelligent learning algorithms to the particle identification of heavy-ion collisions at low and intermediate energies. Multiple intelligence algorithms, including XgBoost and TabNet, were selected to test datasets from the neutron ion multi-detector for reaction-oriented dynamics (NIMROD–ISiS) and Geant4 simulation. Machine learning algorithms based on tree structures and deep learning algorithms e.g. TabNet show excellent performance and generalization ability. Adding additional data features besides energy deposition can improve the algorithm's identification ability when the data distribution is nonuniform. Intelligent learning algorithms can be applied to solve the particle identification problem in heavy-ion collisions at low and intermediate energies.
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2023-11-30
Abstract: Based on the energy conversion of the dynamic electric effect from the solid/liquid contact double
electric layer is the dynamic electromotive potential, this paper studies the static appearance and the release of
the electric field energy of the solid/liquid contact double electric layer, so a special capacitor (P/L/N capacitor) of
solid conductor P / polar liquid L / solid conductor N is constructed. The observations based on experiments are as
follows: (i) the contact double electric layer derived from the internal potential difference polarization of the solid
conductor / polar liquid is equivalent to the external electric field polarization of the ordinary capacitor. The
formation process of the contact double electric layer is the spontaneous charging process of the P/L/N capacitor,
and the P/ L/N capacitor still shows the electric field energy of the contact double electric layer. (ii) Because the
polarized external potential difference of the solid conductor / polar liquid contacting the double electric layer is
always less than the internal potential difference, the short-circuit P/L/N capacitor also has a continuous
electromotive force after the discharge, statically releasing the electric field energy contacting the double electric
layer. (iii) The contact double electric layer of solid conductor / polar liquid is produced spontaneously caused by
mutual contact, and it is also a self-organizing process of absorbing the environmental heat energy into the electric
field energy of the contact double electric layer. P/L/N capacitors realize thermoelectric conversion by releasing
the electric field energy of the contact double electric layer. The above-mentioned phenomenon provides the
possibility for the development of self-generated capacitors and self-supplied power supply.
Keywords: Solid conductor/polar liquid; contact with double electric layer; thermoelectric conversion,
Peer Review Status:Awaiting Review
Subjects: Information Science and Systems Science >> Basic Disciplines of Information Science and Systems Science Subjects: Biology >> Biological Evolution Subjects: Biology >> Biomathematics Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology Subjects: Biology >> Genetics submitted time 2023-10-15
Abstract: Background: In bioinformatics, tools like multiple sequence alignment and entropy methods probe sequence information and evolutionary relationships between species. Although powerful, they might miss crucial hierarchical relationships formed by the reuse of repetitive subsequences like duplicons and transposable elements. Such relationships are governed by “evolutionary tinkering'', as described by Fran c{c}ois Jacob. The newly developed Ladderpath theory provides a quantitative framework to describe these hierarchical relationships.
Results: Based on this theory, we introduce two indicators: order-rate $ eta$, characterizing sequence pattern repetitions and regularities, and ladderpath-complexity $ kappa$, characterizing hierarchical richness within sequences, considering sequence length. Statistical analyses on real amino acid sequences showed: (1) Among the typical species analyzed, humans possess relatively more sequences with large $ kappa$ values. (2) Proteins with a significant proportion of intrinsically disordered regions exhibit increased $ eta$ values. (3) There are almost no super long sequences with low $ eta$. We hypothesize that this arises from varied duplication and mutation frequencies across different evolutionary stages, which in turn suggests a zigzag pattern for the evolution of protein complexity. This is supported by our simulations and examples from protein families such as Ubiquitin and NBPF.
Conclusions: Our method emphasizes “how objects are generated'', capturing the essence of evolutionary tinkering and reuse. The findings hint at a connection between sequence orderliness and structural uncertainty, and suggest that different species or those in varied environments might adopt distinct protein elongation strategies. These insights highlight our method's value for further in-depth evolutionary biology applications.
Peer Review Status:Awaiting Review
Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2023-09-19
Abstract: To accelerate the fractal decoding process, a minimum iterated function system based fast fractal decoding method was proposed in this study. In fractal encoding process, we found that there exists a minimum domain block set (MDBS) which can provide the best-matched domain blocks for all range blocks, and then the domain blocks of MDBS, the range blocks within MDBS, and the associated mapping operations between them constitute the minimum iteration function system (MIFS). In decoding process, MIFS was first recovered in the first iteration. Then, in each of the second to penultimate iterations, only the range blocks within MDBS are reconstructed, and the computations of reconstructing the remaining range blocks can be saved. Finally, all range blocks are reconstructed to obtain the decoded image in the last iteration. Four fractal encoding methods were adopted to assess the performance of the proposed method. Experimental results show that the proposed method can complete the decoding process with fewer computations.
Peer Review Status:Awaiting Review
Subjects: Physics >> Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2023-07-12
Abstract: I review the discovery as well as the band structure of the Zhang lattice.
Peer Review Status:Awaiting Review
Subjects: Mathematics >> Applied Mathematics Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2023-07-04
Abstract:
Based on the Golomb's pseudorandomness assumptions on idea pseudorandom sequences and FIPS 140-2 pseudorandomness test, this paper first presents a new approach for improving the pseudorandomness of pseudorandom sequences. Second, using a generalized synchronization theorem, and three chaotic maps constructs one 8-dimensional chaotic generalized synchronization system (8DCGSS). Then using the 8DCGSS designs a chaotic
pseudorandom number generator (CPRNG). The keyspace of the CPRNG is larger than 2^{1117}. Third, using FIPS 140-2 pseudorandomness test criterions and generalized FIPS 140-2 pseudorandomness test criterions measures, respectively, the pseudorandomness of the keystreams with length 20 000, 100 000 and 1 000 000 generated via the CPRNG, an Matlab PRNG, an RC4 algorithm, and an m-sequence with period 2^{20} - 1, and the corresponding improved keystreams by our approach. The results show that the presented approach can increase significantly the pseudorandomness of the keystreams generated by the four PRNGs. The key streams generated by the m-sequence do not have sound pseudorandomness when the lengths of the key streams are less than 100 000.
Peer Review Status:Awaiting Review
Subjects: Physics >> Nuclear Physics Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2023-06-21
Abstract: Collinear laser spectroscopy is known as one of the powerful tools for the study of nuclear spins, electromagnetic moments and charge radii of the exotic nuclei. Aiming at studying these nuclear properties of unstable nuclei at the Beijing Radioactive Ion-beam Facility (BRIF) and the future High Intensity Heavy-ion Accelerator Facility (HIAF), we have firstly developed a collinear laser spectroscopy apparatus integrated with an offline laser ablation ion source and a laser system. The overall performances of this state-of-the-art technique and device have been commissioned by using the bunched stable ion beam. High-resolution optical spectra of $^{40,42,44,48}$Ca isotopes were successfully measured for the 4$s$ $^{2}S_{1/2}$ $ rightarrow$ 4$p$ $^{2}P_{3/2}$ (D2) ionic transition and the extracted isotope shifts relative to the $^{40}$Ca show an excellent agreement with the literature values. This system is now ready to be applied at the ratioactive ion beam facility, such as BRIF, and has paved the way for further development of the higher-sensitivity collinear resonant ionization spectroscopy.
Subjects: Physics >> Nuclear Physics Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2023-06-20
Abstract: The Shanghai laser electron gamma source (SLEGS) is a powerful tool for exploring photonuclear physics, such as giant dipole resonance (GDR) and pygmy dipole resonance, which are the main mechanisms of collective nuclear motion. The goal of the SLEGS neutron time-of-fight (TOF) spectrometer is to measure GDR and specifc nuclear structures in the energy region above the neutron threshold. The SLEGS TOF spectrometer was designed to hold 20 sets of EJ301 and LaBr3 detectors. Geant4 was used to simulate the efciency of each detector and the entire spectrometer, which provides a reference for the selection of detectors and layout of the SLEGS TOF spectrometer. Under the events of 208Pb, implementations of coincidence and time-of-fight technology for complex experiments are available; thus, y and neutron decay events can be separated. The performance of SLEGS TOF spectrometer was systematically evaluated using ofine experiments, in which the time resolution reached approximately 0.9 ns.
Subjects: Nuclear Science and Technology >> Particle Accelerator Subjects: Physics >> Interdisciplinary Physics and Related Areas of Science and Technology submitted time 2023-05-30
Abstract: In this paper, we propose a novel stacked laser dielectric acceleration structure. This structure is based on the inverse Cherenkov effect and represented by a parametric design formulation. Compared to existing dielectric laser accelerators relying on the inverse Smith–Purcell effect, the proposed structure provides an extended-duration synchronous acceleration field without requiring the pulse front tilting technique. This advantage significantly reduces the required pulse duration. In addition, the easy-to-integrate layered structure facilitates cascade acceleration, and simulations have shown that low-energy electron beams can be cascaded through high gradients over extended distances. These practical advantages demonstrate the potential of this new structure for future chip accelerators.
Peer Review Status:Awaiting Review
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 submitted time 2023-05-01
Abstract: 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.
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 submitted time 2023-05-01
Abstract: 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.
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 submitted time 2022-12-29
Abstract:
A low-noise high-gain 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. The CryoSTM-TIA has a transimpedance gain of 10 Gohm, a bandwidth of over 100 kHz, and an equivalent input noise current power spectral density less than 4 (fA)2/Hz at 100 kHz. The low inherent noise of the CryoSTM-TIA is due to its special design: (1) its pre-amplifier (Pre-Amp) is made of the low-noise cryogenic high electron mobility transistors; (2) the cascode-type configuration for the Pre-Amp is used to avoid Miller effect to reduce its input capacitance CA; (3) the capacitance of the cable connected the Pre-Amp input to the tip, i.e. CI, is minimized; (4) thermal noise sources, such as the feedback resistor, are placed in the cryogenic zone. Its high gain and large-bandwidth are realized together, due to the application of the frequency compensation in the feedback loop, the reduced CA, and the minimized CI. This apparatus can be used for fast high-energy-resolution measurements of scanning tunneling spectra for low conductivity materials, especially for measuring their scanning tunneling shot noise spectra.
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 submitted time 2022-12-29
Abstract: Shot noise is a powerful tool to study quantum systems. In this work, a design of transimpedance amplifier (TIA) for a cryogenic scanning tunneling microscope (CryoSTM) is proposed to meet the requirements of the shot noise measurements for quantum systems. In the TIA, the preamplfier is made of the low-noise low-power cryogenic high electron mobility transistors. With the high transimpedance gain of 1 Gohm, the bandwidth of the proposed TIA is larger than 300 kHz. In the CryoSTM, the TIA with the tip-sample component is called as CryoSTM-TIA. The bandwidth of the proposed CryoSTM-TIA is still larger than 300 kHz. Its equivalent input noise current power spectral density is less than 30 (fA)2/Hz at 100 kHz. It is detailed, for quantum systems, by using the CryoSTM-TIA, how to measure scanning tunneling current spectra, scanning tunneling differential conductance spectra, and scanning tunneling noise current power spectra, in atomic scale, and then extract their scanning tunneling shot noise spectra. Thus, it is possible to study novel quantum phenomena in various quantum systems by measuring shot noise with the CryoSTM-TIA, such as the Andreev reflection in atomic scale, the Kondo effect in a single molecular magnet, and the existence of Majorana bound states, etc.