bluuebunny/crossref_metadata_2025 huggingface dataset:
Protein nanoribbons template enamel mineralization
Authors: Bai Yushi , Yu Zanlin , Ackerman Larry , Zhang Yan , Bonde Johan , Li Wu , Cheng Yifan , Habelitz Stefan
Published: August 2020

Significance

How does enamel achieve its remarkable microstructure? This study reveals that the cleaved enamel protein amelogenin adopts a ribbon-like supramolecular structure that controls the growth of mineral into nanofibers. Protein nanoribbons of 15 to 20 nm in width were identified in dental enamel and replicated from a recombinant protein mimicking an enzymatic cleavage product of human amelogenin. In mineralization experiments, these protein structures templated the growth of highly oriented apatite nanofibers along their backbone from an amorphous precursor. In accordance with the natural process of enamel development, this in vitro model suggests that the ability of amelogenin nanoribbons to guide fibrous apatite growth is regulated by enzymatic processing and their interaction with acidic nonamelogenin proteins in the developing enamel matrix.
Lysosomal activity regulatesCaenorhabditis elegansmitochondrial dynamics through vitamin B12 metabolism
Authors: Wei Wei , Ruvkun Gary
Published: August 2020

Significance

The balance of mitochondrial fission and fusion, two aspects of mitochondrial dynamics, is important for mitochondrial function. In this study, we show thatCaenorhabditis eleganslysosomal activity regulates mitochondrial dynamics by affecting mitochondrial fission through interfering the metabolism of a micronutrient, vitamin B12. Vitamin B12 is exclusively obtained from diets in animals, includingC. elegansand humans, and its uptake is mediated by the lysosome. We show that lysosomal dysfunction causes vitamin B12 deficiency that leads to reduction of methionine and S-adenosylmethionine to in turn increase mitochondrial biogenesis and fission. Our study provides insight on the interactions between mitochondrial function and micronutrient metabolism.
Associated motion, direction and (exchoative) aspect in Ethiopian Komo
Authors: Otero Manuel A.
Published: August 2020

Komo (Koman) of Ethiopia has an obligatory paradigm ofdeictic directional(dd) verb morphology that, among its functions, indicatesdirectionofmotionrelative to a deictic reference point,associated motionand grammaticalaspectwhen collocated with verb roots of different semantic classes. The semantic components of amotion eventunderlie the Komoddsystem and the grammatical aspect of a predicate can be directly mapped to the bounded/unboundedpathprofile. The Associated Motion function contains a bounded path which entails arrival at or departure from a reference point and, as a result, imparts aspectual telicity to the predicate. The Direction function by contrast, contains an unbounded path that expresses motion towards a reference point and does not impart aspectual telicity. Further, some morphemes express exchoativity, or the ‘exiting’ of a state, a rare if unattested grammatical category.
Markers of epistemic modality and their origins
Authors: Engberg-Pedersen Elisabeth
Published: August 2020

Native deaf signers express epistemic modality by different means: mental-state words, clause-internal particles, signs indicating hypothesis, and nonmanually. The data for this study come from two unrelated sign languages, Danish Sign Language and Japanese Sign Language. In dialogues the signers use both calques of majority-language words and signs that appear to have emerged in the sign languages only. Based on the multifunctionality of some word forms, the origin of the epistemic modal particles may be traced back to tags, interjections, and lexical signs, a route motivated by interaction and also found in unrelated spoken languages. Furthermore, in both sign languages, the first-person pronoun can be used, without a verb, as an epistemic “anchor” of a proposition, a construction that seems specific to languages in the gestural-visual modality. Another modality-specific feature is the possibility of transferring the expression of a marker of epistemic uncertainty from one articulator to another.
Manufacturing large 2A14 aluminium alloy cylinders by a warm rolling technology
Authors: Tong Dengliang , Yi Youping , He Hailin , Huang Shiquan , Guo Wanfu
Published: August 2020

This paper aims at the problem of high performance manufacturing of large 2A14 Al-alloy cylindrical components for aerospace applications. A warm rolling process was put forward to substantially refine the grains and secondary phases of 2A14 Al alloys. The results indicated that compared with hot rolling, warm rolling was easier to implement to form abundant subgrains and fully crushed the coarse particles. Coarse second phases dissolved and the precipitated T phases (AlCuMn) hindered the migration of grain boundaries and restrained grain growth during the heat treatment.The tensile strength, yield strength and elongation of the 2A14 aluminium alloy were significantly increased by 59 MPa (an increase of 14%), 71 MPa (an increase of 21%), 4% (an increase of 67%), respectively.
Dietary composition of birds in isolated ecosystems: a case study of Black Wood Pigeon in Republic of Korea
Authors: Choi Soon Kyoo , Park Yung Chul , Park Sung Wan , Kim Jae Woong , Kim Woo Yuel
Published: August 2020

We studied the feeding ecology of the Black Wood Pigeon (Columba janthina), a species endemic to the East Asian Pacific Islands, and determined the species’ dietary composition and food preferences on Ulleung Island, South Korea, through field observations. From March 2016 to February 2018, the diversity of food items consumed was low, with the 10 most common plant species (from a total of 33) accounting for over 80%. Food availability varied depending on plant abundance, but this influence was minimized because of factors such as delayed fruit ripening. Drupes were the most favored food items (60–68%) but were replaced by nuts and weed seeds during the spring and winter months. Dietary composition and food preferences were related to the abundance of food items based on their phenology, but a steady, high preference forAphananthe asperawas observed throughout the study period. The abundance ofPrunus takesimensisin June was correlated with changes in the Black Wood Pigeon population. This study is the first to assess the feeding ecology of Black Wood Pigeons using field observations and suggests that the availability of different food items affects population changes on the East Asian Pacific islands.
Multi-functional vanadium dioxide integrated metamaterial for terahertz wave manipulation*
Authors: Zhao Jian-Xing , Song Jian-Lin , Zhou Yao , Zhao Rui-Long , Liu Yi-Chao , Zhou Jian-Hong
Published: August 2020

We proposed a vanadium dioxide (VO2)-integrated multi-functional metamaterial structure that consists of three metallic grating layers and two VO2 films separated by SiO2 dielectric spacers. The proposed structure can be flexibly switched among three states by adjusting temperature, incident direction, and polarization. In state 1, the incident wave is strongly transmitted and perfectly converted to its orthogonal polarization state. In state 2, the incident wave is perfectly absorbed. In state 3, incident wave is totally reflected back. The working frequency of the multi-functional metamaterial can be arbitrarily tuned within a broad pass band. We believe that our findings are beneficial in designing temperature-controlled metadevices.
Quantum speed limit time and entanglement in a non-Markovian evolution of spin qubits of coupled quantum dots
Authors: Bagheri Harouni M.
Published: August 2020

Quantum speed limit time and entanglement in a system composed of coupled quantum dots are investigated. The excess electron spin in each quantum dot constitutes the physical system (qubit). Also the spin interaction is modeled through the Heisenberg model and the spins are imposed by an external magnetic field. Taking into account the spin relaxation as a non-Markovian process, the quantum speed limit and entanglement evolution are discussed. Our findings reveal that increasing the magnetic field leads to the faster quantum evolution. In addition, the temperature increment causes the longer quantum speed limit time as well as the entanglement degradation.
Generation and manipulation of bright spatial bound-soliton pairs under the diffusion effect in photovoltaic photorefractive crystals*
Authors: Zhang Ze-Xian , Zhao Xiao-Yang , Li Ye , Cui Hu , Luo Zhi-Chao , Xu Wen-Cheng , Luo Ai-Ping
Published: August 2020

The generation and propagation characteristics of bright spatial bound-soliton pairs (BSPs) are investigated under the diffusion effect in photovoltaic photorefractive crystals by numerical simulation. The results show that two coherent solitons, one as the signal light and the other as the control light, can form a BSP when the peak intensity of the control light is appropriately selected. Moreover, under the diffusion effect, the BSP experiences a self-bending process during propagating and the center of the BSP moves on a parabolic trajectory. Furthermore, the lateral shift of the BSP at the output face of the crystal can be manipulated by adjusting the peak intensity of the control light. The research results provide a method for the design of all-optical switching and routing based on the manipulation of the lateral position of BSPs.
Generation of atomic spin squeezing via quantum coherence: Heisenberg–Langevin approach
Authors: Shao Xuping
Published: August 2020

Taking into account the dephasing process in the realistic atomic ensemble, we theoretically study the generation of atomic spin squeezing via atomic coherence induced by the coupling and probe fields. Using the Heisenberg–Langevin approach, we find that the perfect spin squeezing in the X component can be obtained while the coupling and probe fields produce the maximum coherence between the ground state sublevels 1 and 2. Moreover, the degree of atomic spin squeezing in the X component can be strengthened with the increasing atomic density and/or Rabi frequency of the mixing field. The theoretical results provide a proof-of-principle demonstration of generating the atomic spin squeezing via quantum coherence in the realistic atomic ensemble which may find potential applications in quantum information processing and quantum networks.
Two-step phase-shifting Fresnel incoherent correlation holography based on discrete wavelet transform*
Authors: Wu Meng-Ting , Zhang Yu , Tang Ming-Yu , Duan Zhi-Yong , Ma Feng-Ying , Du Yan-Li , Liang Er-Jun , Gong Qiao-Xia
Published: August 2020

Fresnel incoherent correlation holography (FINCH) has the ability to generate three-dimensional images with a super-resolution by using incoherent sources. However, there are unwanted direct current term and twin image in interferograms, so it is of great significance to find a method to eliminate them. Phase-shifting technology is a most widely used technique for this task, but its three-step phase-shifting is not suitable for the instantaneous measurement of dynamic objects, and the quality of reconstructed image with the traditional two-step phase-shifting is lower. In this paper, we present a method of enhancing the resolution through using a two-step phase-shifting technology based on the discrete wavelet transform. After two-step phase-shifting, the resulting hologram is a superposition of multiple forms. The frequency of the resulting hologram is decomposed into different levels through using discrete wavelet transform, then the image is reconstructed after retrieving the low frequency band. Various experiments have verified the effectiveness of this method.
Compound-induced transparency in three-cavity coupled structure*
Authors: Qin Hao-Ye , Yin Yi-Heng , Ding Ming
Published: August 2020

We propose a three-cavity coupled cavity optomechanical (COM) structure with tunable system parameters and theoretically investigate the probe-light transmission rate. Numerical calculation of the system’s spectra demonstrates distinctive compound-induced transparency (CIT) characteristics, including multiple transparency windows and sideband dips, which can be explained by a coupling between optomechanically-induced transparency (OMIT) and electromagnetically-induced transparency. The effects of optical loss (gain) in the cavity, number and topology of active cavity, tunneling ratio, and pump laser power on the CIT spectrum are evaluated and analyzed. Moreover, the optical group delay of CIT is highly controllable and fast–slow light inter-transition can be achieved. The proposed structure makes possible the advantageous tuning freedom and provides a potential platform for controlling light propagation and fast–slow light switching.
Chaotic state as an output of vacuum state evolving in diffusion channel and generation of displaced chaotic state for quantum controlling*
Authors: Chen Feng , Xiong Wei , Fang Bao-Long , Fan Hong-Yi
Published: August 2020

We show that chaotic state can be produced as an output of vacuum state evolving in diffusion channel, while displaced chaotic state is output of a coherent state evolving in diffusion channel. We also introduce the thermo vaccum state for the displaced chaotic state and evaluate the average photon number. The displaced chaotic state may be used exhibiting quantum controlling.
Low lattice thermal conductivity and high figure of merit in p-type doped K3IO*
Authors: Wang Weiqiang , Dai Zhenhong , Zhong Qi , Zhao Yinchang , Meng Sheng
Published: August 2020

Based on first-principles calculations, Boltzmann transport equation and semiclassical analysis, we conduct a detailed study on the lattice thermal conductivity κ
L, Seebeck coefficient S, electrical conductivity σ, power factor S
2
σ and dimensionless figure of merit, zT, for K3IO. It is found that K3IO exhibits relatively low lattice thermal conductivity of 0.93 W⋅m−1⋅K−1 at 300 K, which is lower than the value 1.26 W⋅m−1⋅K−1 of the classical TE material PbTe. This is due to the smaller phonon group velocity ν
g and smaller relaxation time τλ
. The low lattice thermal conductivity can lead to excellent thermoelectric properties. Thus maximum zT of 2.87 is obtained at 700 K, and the zT = 0.41 at 300 K indicate that K3IO is a potential excellent room temperature TE material. Our research on K3IO shows that it has excellent thermoelectric properties, and it is a promising candidate for applications in fields in terms of thermoelectricity.
The theory of helix-based RNA folding kinetics and its application*
Authors: Gong Sha , Liu Taigang , Wang Yanli , Zhang Wenbing
Published: August 2020

RNAs carry out diverse biological functions, partly because different conformations of the same RNA sequence can play different roles in cellular activities. To fully understand the biological functions of RNAs requires a conceptual framework to investigate the folding kinetics of RNA molecules, instead of native structures alone. Over the past several decades, many experimental and theoretical methods have been developed to address RNA folding. The helix-based RNA folding theory is the one which uses helices as building blocks, to calculate folding kinetics of secondary structures with pseudoknots of long RNA in two different folding scenarios. Here, we will briefly review the helix-based RNA folding theory and its application in exploring regulation mechanisms of several riboswitches and self-cleavage activities of the hepatitis delta virus (HDV) ribozyme.
Synthesis and Physical Property Measurements in Misfit Transition Metal Dichalcogenide (SbS)1.16TaS2
Authors: Doyama S , Ohta S , Sakata H
Published: August 2020

We report the single crystal growth and superconducting transition of a misfit layered compound (SbS)1.16TaS2. We succeed in the single crystal growth with flux method. The electrical resistivity measurements revealed the superconducting transition temperature of this material as 2.9 K, which was consistent with the previous research. Scanning tunneling microscopy measurements show two kinds of surfaces corresponding to TaS2 and SbS layers, indicating successful growth of the single crystal consist of stacking of these layers.
Local density of States in Two-Dimensional Nano-Structured Superconducting Systems with Superconductor-Normal Metal Interfaces
Authors: Fukui Saoto , Wang Zhen , Kato Masaru
Published: August 2020

In nano-structured superconductors, it is important to consider a discreteness of energy levels instead of continuous energy levels due to the quantum confinement effect. This discreteness causes an appearance of many peaks in a density of state (DOS). In this paper, the effect of the discreetness of energy level or the effect of the quantum confinement on the DOS in superconducting systems with superconductor / normal metal (S/N) interfaces are focused. In particular, in nano-sized finite systems, a local density of state (LDOS) becomes strongly spatial dependent because of non-uniform spatial distributions of a gap energy and a pair amplitude. We investigate the pair amplitude and the LDOS by solving the Bogoliubov-de Gennes equations self-consistently. The proximity effect leads to a penetration of the pair amplitude into the normal metal region. Then, the pair amplitude in the normal metal decays non-monotonously because of the effect of the nano-sized finite system. On the other hand, the spatial-averaged LDOS plots as a function of the energy have many peaks in both superconductor and normal metal regions. Also, a contribution of the normal metal to the superconductor causes an appearance of peaks of the LDOS at the energy below the gap energy. In the SNS junction, when width of the normal metal increases, these peaks at the energy below the gap energy appear clearly.
31P NMR studies of an iron-based superconductor Ba0.5Sr0.5Fe2(As1−x
P
x
)2 with T
c = 29 K
Authors: Itoh Yutaka , Adachi Seiji
Published: August 2020

We report 31P NMR studies of an oriented polycrystalline superconductor of Ba0.5Sr0.5Fe2(As1−x
P
x
)2 with x ∼ 0.4 (T
c = 29 K) at T = 14−325 K and B
0 = 1 and 5 T. The 31P Knight shift Kab
at B
0 ⊥ c shows a nearly T-independent uniform spin susceptibility above T
c and a spin singlet decrease below T
c. The 31P nuclear spin-lattice relaxation rate 1/T
1 shows an asymptotic behavior of a + bT (a and b are constants) at T > 100 K and the minimum at 40 K with an upturn toward T
c. The a term in 1/T
1 indicates the presence of two-dimensional antiferromagnetic spin fluctuations. The negative θ = −15 K of the Curie-Weiss-type antiferromagnetic spin susceptibility

χ
(
Q
)
∝

1
/

(
T
+
θ
)

in the analysis of 1/T
1
T suggests antiferromagnetic instability in the superconducting state. Discussions are made from the self-consistent renormalization (SCR) theory for the spin fluctuations with interlayer correlation.
Chemical pressure effect of the electron-doped FeSe films with an electric double-layer-transistor structure
Authors: Shikama N , Sakishita Y , Nabeshima F , Maeda A
Published: August 2020

We investigated chemical pressure effect of the electron-doped FeSe1−x
S
x
and FeSe1−y
Te
y
on LaAlO3 (x ≤ 0.25, y ≤ 0.5) with the electric double layer transistor structure. T
c of all the FeSe1−x
S
x
and FeSe1−y
Te
y
films except y = 0.5 is increased by doping electron with gate voltage V
G = +5 V. T
c of the electron-doped FeSe1−x
S
x
and FeSe1−y
Te
y
is decreased monotonically by substituting Se for both S and Te. The behavior is similar to those of the intercalated FeSe1−x
S
x
and FeSe1−y
Te
y
and the electron-doped FeSe0.5Te0.5 with the solid-ion-conductor field-effect transistor structure, but quite different from that of the pristine FeSe1−x
S
x
and FeSe1−y
Te
y
. This difference is considered to originate from the difference of the Fermi surface topology, which suggests that the superconducting mechanism of the electron-doped FeSe is different from that of the pristine FeSe.
Anion height dependence of critical current densities for Fe Te1-x Sex bulk single crystals
Authors: Miyaki K , Miura O , Mizuguchi Y
Published: August 2020

We have fabricated FeTe1-xSex high quality bulk single crystals. The crystals with different composition of x = 0.375, 0.4, 0.45, 0.46 and 0.475 were prepared by the melting method with two stage heat treatment. The crystal structure and superconducting properties were evaluated. Temperature dependence of magnetization showed that low-T
c region exists inside the crystals. Critical temperature T
c was the highest value of 14.3 K for the crystal with x = 0.45. Critical current densities J
c under the magnetic fields parallel to the c-axis at 4.2 K achieved 1.52 and 0.72 × 105 A / cm2 at 0 T and 5 T respectively for the crystal with x = 0.4. The crystal lattice parameters were examined by Rietveld refinement. The anion height from Fe layer was calculated using the obtained parameters. We investigated the anion height dependence of T
c and J
c and mentioned an important role of excess Fe about the magnetic flux pinning.
Effects of Point Defects Introduced by Co-doping and Proton Irradiation in CaKFe4As4
Authors: Kobayashi Y , Pyon S , Takahashi A , Tamegai T
Published: August 2020

Introduction of point defects into superconductors through proton irradiation enhances their critical current density (J
c). Similarly, chemical doping can also produce point defects, leading to the enhancement of J
c. Iron-based superconductors (IBSs) have been investigated as promising materials for practical applications because of their large J
c at high magnetic fields and temperatures. Recently, another promising IBS CaKFe4As4 (1144-type) was found, and attracts much interest due to its characteristic feature such as stoichiometric superconductivity and the presence of novel planar defects. We have grown single crystals of Co-doped CaKFe4As4 and clarified the effect of chemically-introduced point defects on J
c. We also introduced point defects through 3 MeV proton irradiation, and compared the effect of point defects to J
c.
Unconventional properties of high-temperature superconducting cuprates
Authors: Nishi Kazuhisa
Published: August 2020

In spite of much interest in various unconventional properties of superconducting cuprates such as the anisotropic superconductivity, the pseudogap state, the competing state in the underdoped region, strange metal in normal state, and anomalies in the optical sum rules etc, its microscopic mechanism still remains unsolved issues. Here these properties are considered using our recently proposed theory emphasizing that the electronic state of superconductors can be described by doping-dependent composite fermions. It is found that the anisotropy of the superconductive gap and the pseudogap are evaluated, the competing states is derived by mixed states model, and that T-linearity of resistivity and the anomaly of optical sum rules in the nearly optimal doping can be derived from considering the interplay between the composite fermion bands. It is also suggested that a crossover separating the strange metal and the normal metal in the overdoped region can be explained by the coupling effect of composite fermions
Progress in High-Speed Spin Testing of Superconducting Wire and Tapes for High-Field NMR Magnet Qualification
Authors: Voccio J. , Rueckert F. J. , Curtsmith P. , Favazza C. J. , Boyle J. , Franchi M. , Allen C. , Tetreault N. , Munson L. , Nedbal V. , Weekes-Tulloch A.
Published: August 2020

This paper summarizes the status of a 3-year, NIH-funded research project to study the strength of high temperature superconductors under high circumferential hoop stress, in order to qualify these materials for high-field (> 1 GHz-class NMR magnets. The unique approach presented here is to spin test coils at high rotational speeds, approaching 100,000 rpm, in order to induce the necessary hoop stress. Thermal strain compatibility between the Bi-2212 wire and Inconel wire has been qualified, including thermal cycling. Assembly and testing of the first low-speed (< 30,000 rpm) rotor is now in process, and the design of second, higher speed (> 60,000 rpm) rotor, is also underway.
Peculiarities of dissipative phenomena in coated YBCO tapes carrying constant current during flux creep
Authors: Romanovskiy V. R.
Published: August 2020

The effect of the flux creep on the dissipation phenomena in tapes based on YBCO leading to the essentially non-linear voltage-current characteristic of a superconductor is discussed. The obtained results are compared to the calculations made in the framework of the existing thermal stabilization theory based on the model assuming a jump transition from a superconducting state to a normal one. It is shown that the latter model incorrectly describes the dissipation modes, first of all, in a temperature range up to the critical temperature of the superconductor. It is proved that the type of nonlinearity of voltage-current characteristics has a significant effect on the dissipative phenomena in tapes in this temperature region. As a result, the allowable currents stably flowing in superconducting tapes may be higher than a priory defined critical current determined for continuously rising voltage-current characteristic. Correspondingly, the critical current of high-Tc superconducting tapes, which is determined using continuously increasing voltage-current characteristic, has no physical meaning. Therefore, fundamentals of the thermal stabilization theory must consider the real temperature dependence of the dissipated energy in high-Tc superconducting tapes, which depends on the nonlinearity of their voltage-current characteristic.
3D Numerical Study on Magnetization Losses in Twisted Soldered-Stacked-Square (3S) HTS Wires Based on Homogenized Models
Authors: Yao L P , Lv Y Y , Gu F , Zhong L H , Duan X H , Song M , Li L , Li Z Y , Hong Z Y , Jin Z J
Published: August 2020

Magnetization loss is an important parameter in the application of high temperature superconductivity (HTS) power devices. In order to reduce magnetization losses, a novel soldered-stacked-square (3S) HTS wire with 1 mm width is firstly proposed and manufactured by our group. In previous work, numerical and experimental results have shown the magnetization loss in the 3S wire is one order smaller than that in the original 4 mm tape under perpendicular magnetic field. However, large eddy current loss and coupling loss will be generated under parallel field. Therefore, to further reduce the magnetization loss, the 3S wire has been twisted and investigated numerically in this paper. Firstly, two-dimensional (2D) numerical models are built for calculating the magnetization loss in untwisted 3S wires. To simplify the computation, a homogeneous bulk-like model is built which does not include the individual tapes of stack. The results show that the losses calculated by the homogenized model is similarly equal to the original results. Based on this, the homogeneous technique is further applied in three-dimensional (3D) numerical models of the twisted 3S wire. The results indicate that the homogenized model could make a good predict for the losses in twisted wires. What’s more, the magnetization losses in twisted wires is compared with those in untwisted wires to verify that twisting process could actually reduce the magnetization loss of the novel superconducting wire.
Fabrication of (Ba,Na)Fe2As2 round wires and tapes using HIP process
Authors: Miyawaki D , Pyon S , Awaji S , Kajitani H , Koizumi N , Kito H , Ishida S , Yoshida Y , Tamegai T
Published: August 2020

We fabricated round wires and tapes of (Ba,Na)Fe2As2 using hot isostatic press (HIP) process, and evaluated their critical current density (Jc
). Polycrystalline powders were synthesized by two methods by mixing raw materials in a planetary ball mill or by using pre-synthesized precursors (BaAs, NaAs, Fe2As). Transport Jc
of best wire reached 95 kA/cm2 under self-field and 40 kA/cm2 at 100 kOe. We also fabricated HIP tapes using the same powder and discuss their detailed characterizations. In particular, X-ray diffraction is extensively applied to the evaluation of the degree of texturing of the tape, and discuss its relationship with J
c.
Energy-Resolved Neutron Imaging using a Delay Line Current-Biased Kinetic-Inductance Detector
Authors: Shishido Hiroaki , Nishimura Kazuma , Dang Vu The , Kojima Kenji M. , Koyama Tomio , Oikawa Kenichi , Harada Masahide , Miyajima Shigeyuki , Hidaka Mutsuo , Oku Takayuki , Soyama Kazuhiko , Aizawa Kazuya , Suzuki Soh Y. , Ishida Takekazu
Published: August 2020

We demonstrate the development of an energy resolved neutron transmission imaging system via a solid-state superconducting detector, called current-biased kinetic-inductance detector (CB-KID). CB-KIDs comprise X and Y superconducting Nb meanderlines with Nb ground plane and a 10B conversion layer, which converts a neutron to two charged particles. High-energy charged particles are able to create quasi-particle hot spots simultaneously in the X and Y meander lines, and thus, the local Cooper pair density in meander lines is reduced temporary. When DC-bias currents are fed into the meander lines, double pairs of voltage pulses are generated at the hot spots and propagate toward both ends of the meander lines as electromagnetic waves. The position of the original hot spot is determined by a difference in arrival times of the two pulses at the two ends for X and Y meander lines, independently. This is so-called the delay-line method, and allows us to reconstruct the two-dimensional neutron transmission image of a test sample with four signal readout lines. We examined the capability of high spatial and energy (wavelength) resolved neutron transmission imaging over the sensor active area of 15 ×15 mm2 for various samples, including biological and metal ones. We also demonstrated the capability for the Bragg edge transmission and an energy-resolved neutron image in which stainless-steel specimens were discriminating from other specimens.
Theory for the response of a superconducting kinetic inductance detector to an electromagnetic wave packet
Authors: Koyama T , Ishida T
Published: August 2020

Voltage pulses generated by local heating due to the irradiation of an electromagnetic (EM) wave packet in a superconducting current-biased kinetic inductance detector are theoretically investigated on the basis of our previous theory [J. Phys. Conf. Ser.
1293, 012050]. The growth and decay of a hot spot created by an EM wave packet is described with the heat diffusion equation coupled with the time-dependent Ginzburg-Landau (TDGL) equation. Variation in the kinetic inductance of the current-biased stripline in the detector induced by a hot spot is explicitly derived. We clarify the characteristic feature in the shape of the voltage pulses.
Kinetic inductance neutron detector operated at near critical temperature
Authors: Dang Vu The , Nishimura Kazuma , Shishido Hiroaki , Harada Masahide , Oikawa Kenichi , Miyajima Shigeyuki , Hidaka Mutsuo , Oku Takayuki , Soyama Kazuhiko , Aizawa Kazuya , Kojima Kenji M , Koyama Tomio , Malins Alex , Machida Masahiko , Ishida Takekazu
Published: August 2020

We previously succeeded in constructing and demonstrating the capability of a neutron imaging system based on a superconducting current-biased kinetic inductance detector (CB-KID). In the present work, we systematically studied the characteristics of the superconducting neutron detector to improve the spatial resolution and detection efficiency. We found that the number of neutron detection events with CB-KID remarkably increased when the detector temperature increased from 4 K to the critical temperature T
c. We observed systematic changes of neutron signals as a function of the detector temperature from 4 K to T
c. We evaluated the detection efficiency of the CB-KID detector, and compared with PHITS Monte Carlo simulations, which modeled the sequential physical processes for the 10B(n,α)7Li reaction, the transport dynamics, and the energy deposition by particles including neutrons, 4He particles, 7Li particles, photons, and electrons.
Development of scanning SQUID microscope system and its applications on geological samples: A case study on marine ferromanganese crust
Authors: Oda H , Kawai J , Usui A , Yamamoto Y , Noguchi A , Miyagi I , Miyamoto M , Fujihira J , Sato M
Published: August 2020

We present developments and applications of a high resolution scanning superconducting quantum interference device (SQUID) microscope for imaging magnetic field of geological samples at room temperature. A directly coupled low-temperature SQUID with a 200 μm × 200 μm pickup loop was mounted on a sapphire rod and separated from room temperature by a sapphire window. The environmental noise of the SQUID was successfully reduced by subtracting the signal of an additional reference SQUID placed inside a cryostat. The resulting system noise level was estimated to be about 50 pT. A geological thin section could be placed on a non-magnetic sample holder with an XYZ stage for scanning in an area of 100 mm × 100 mm. The minimum achievable distance from the SQUID to the sample is measured as ∼200 µm. An application of the SSM to a marine ferromanganese crust successfully provided beautiful stripe patterns in the magnetic images. The patterns could be correlated to the history of geomagnetic field reversals. The boundaries of the magnetic polarity domains were useful guides for the estimation of the deposition age by correlation with the standard geomagnetic polarity timescale. The established age model gave an average growth rate of ∼2.7 mm/Ma, which is consistent with that obtained by radiometric dating using 10Be (∼2.6 mm/Ma).
Electronic Design Automation tools for superconducting circuits
Authors: Fourie Coenrad J
Published: August 2020

Superconducting integrated circuits have long been completely handcrafted or at best designed with a loose collection of tools that require manual manipulation of data and design transfer between tools. Electronic Design Automation (EDA) software development requires significant investment of resources to track the evolution of integrated circuit fabrication processes, which has only been possible commercially for highly successful semiconductor integrated circuit processes. The IARPA SuperTools project which started in 2017 is the largest known investment to date made in superconducting EDA tool development. SuperTools is divided into two main categories: high-level tools for the synthesis of digital logic circuits, clock networks and placed-and-routed layouts for systems such as processors with millions of logic gates; and physical-level tools for the design, simulation, optimisation, verification, layout and parameter extraction of devices and digital logic cells with the inclusion of fabrication process simulation. In this paper the modules developed for the ColdFlux project under SuperTools are discussed from device modelling to chip tape-out. Progress on parameter extraction tools is highlighted.
A two-step routing method with wire length budgeting for PTL routing of SFQ logic circuits
Authors: Kitamura K , Takagi K , Takagi N
Published: August 2020

A PTL routing method for large-scale SFQ logic circuits is proposed. In this method, a routing problem is solved in two steps; global routing and detailed routing. In the global routing, a routing region is split into rectangular subregions and paths connecting them are obtained. Wire length budgeting is introduced into the global routing for allocating sufficient amount of routing resources to each net considering wire length matching in the detailed routing. In the detailed routing, exact wiring routes are determined based on a solution of the global routing and wire length matching is performed at each subregion. The global routing with wire length budgeting is formulated and an algorithm for it is proposed. In the proposed global routing algorithm, initial routes are searched at first using the rip-up and reroute technique, and then, routing resource distribution is calculated by constructing a flow-graph and solving a max-flow problem. If distribution of routing resources fails, global route extension is conducted to allocate additional routing resources to nets. The routing resource distribution and the global route extension are repeated until sufficient resources are allocated to all nets. As a design example, a 16 bit Sklansky adder was designed using the proposed method. Wire length matching in detailed routing was succeeded and the target frequency of 50 GHz was achieved.
Prototyping new type Bi2Sr2CaCu2O8+x devices using a consumer-oriented inkjet printer
Authors: Yamada Y , Okamoto T
Published: August 2020

We have tried the microfabrication of Bi2Sr2CaCu2O8+x (Bi2212) thin films. The thin films were prepared by the metal-organic decomposition method. The photoresist was printed on the thin films using a consumer-oriented inkjet printer. Filling a black cartridge with resist diluted 3 times with ethanol and printing with 80% black can minimize both the scattering of the resist and the areas where the resist is not on. After etching the thin films with citric acid, the photoresist was stripped with NaOH. Under the printing and etching conditions in this report, the resist width was about 0.05 mm wider than the desired width, and the undercut width was about 0.08 mm. We succeeded in forming a bridge of about 75 μm.
Complex research of the unclosed HTS shield for improving homogeneity of the magnetic field
Authors: Kulikov E , Dorofeev G L , Kozlowski K , Tomków L , Drobin V M
Published: August 2020

Homogeneous magnetic fields are required in different applications. The resolution of MRI techniques depends on the quality of the magnetic field, as well as the efficiency of electron cooling systems used at particle accelerators. Unclosed magnetic shield made of superconducting tapes is able to nullify the radial component of a solenoidal magnetic field, forming the long region of the homogeneous magnetic field. The shield is a lengthwise winding made from YBCO tapes are wound along a carcass generatrix. Then it is positioned coaxially inside an electromagnet. The measurements were carried out under quasistationary conditions, magnetic fields up to 1 kG at 77K. This paper discusses the design of the superconducting shield and presents experimental and numerical studies into the homogeneity of the magnetic field in solenoids with the superconducting shield.
Experimental study on temperature distribution measurement of an optical fiber encapsulated coil in liquid nitrogen
Authors: Lv Y Y , Jiang J J , Wang L B , Li Z Y , Hong Z Y
Published: August 2020

Fast quench detection technique is extremely important for high temperature superconducting (HTS) applications, especially HTS magnets. As one of potential candidates, the method based on distributed optical fiber sensors were suggested recently. To keep HTS tape structure intact and reduce thermal propagation time from HTS tape to optical fiber, a method that optical fiber is encapsulated in HTS tape edge along the length direction could be satisfied. In this paper, an optical fiber encapsulated tape (OF-tape) was successfully fabricated. To verify the feasibility of temperature measurement for this tape, a coil wound with OF-tape and a distributed temperature sensor (DTS) system were prepared. The main results show that temperature of the coil can be measured accurately in air and in liquid nitrogen. After suffering impulse currents with peak values of 570 A and durations of 1, 2, and 3 s, temperature rises of the coil are 98.5, 137.8, and 271.0 K, respectively. Moreover, the highest temperature appears from 3.6 m to 21.7 m of the coil when it suffers the impulse current of 460 A/3 s.
Heat leak of cryogenic pipe for superconducting dc power transmission line (SCDC)
Authors: Yamaguchi Sataro , Kanda Masae , Ivanov Yury
Published: August 2020

Main loss of the superconducting DC power transmission line (SCDC) comes from the heat leak of the cryogenic pipe because of no internal heat generation in the dc cable. It should be minimized to realize the high performance of SCDC. The heat leak of the cryogenic pipe depends on the ambient temperature, and when it is high, the heat leak is also high. Therefore, we estimated the sensitivity of the heat leak for the ambient temperature at first, and estimated the effect of this for the distance between the cryogenic stations. The major process of the heat leak is the heat transfer through the multi-layer insulation (MLI) and the second process is the thermal conduction of the support leg of the inner pipe in our design. The MLI is made from the multi-layers of the aluminium-coated thin film (ACTF) with the spacer, and the support leg is made of the glass fiber reinforced plastic (GFRP). The aluminium layer reflects the infrared light highly to reduce the heat transfer by radiation, and the spacer can prevent the direct contact with the ACTF. Therefore, the weight of the MLI should be light to minimize the thermal transfer of the spacer. We tested various types of MLI to find the optimum MLI structure experimentally. Usually, the measurement of the heat leak is not easy in an actual cryogenic pipe and we need the long experiment time and a relatively large instrument to evaluate the heat leak. However, since we need to evaluate many MLIs, we developed the different way to estimate the heat leak through the MLI by a small experimental device. To find the optimum MLI, we started to test three samples of the MLI supplied from Kaneka Corp., and measured the temperature of the MLI. Since the heat capacity of MLI is low, we used the 50-micron meters thermocouple (TC) and attached it to measure the temperature of the MLI carefully. The result of the experiment shows that we found that the net type of the spacer is better than the spacer used in Ishikari project, and the heat leak would be half of the Ishikari project. We also measured the thermal conductivity of two test samples of GFRP to reduce the heat conductions of the support leg. The thermal conduction of these two GFRPs are almost 1/2 to 1/4 of the recommended values of the NIST. Because of these efforts to reduce the heat leak of the cryogenic pipe, we can expect the target values of the heat leak is a half of the Ishikari project in the next project, and if we can reach this value, we can extend the distance of the cryogenic stations to ∼100km actually on the earth. The values of this distance is important to transfer the electricity for all over the world like the gas and oil pipeline in the present time.
Heat leak measurement of the cryogenic pipe for the superconducting power transmission at different surface temperatures
Authors: Watanabe Hirofumi , Takeuchi Toru , Miyake Katsuya , Yamaguchi Satarou
Published: August 2020

The heat leak of the cryogenic pipe constituting a transmission line of the superconducting power transmission depends on the surface temperature of the cryogenic pipe, because the heat leak is mainly caused by the radiative and conductive heat transfers. The heat leak of the cryogenic pipe for the superconducting power transmission has been measured with respect to its surface temperature ranging from -3 to 53 °C to investigate the effect of the surface temperature variation and to obtain data for the installation of cables in different places with different environmental conditions. The cryogenic pipe used for the measurements has two inner pipes, called cable pipe and return pipe, in a single outer pipe. For the cable pipe the heat leak of 0.82 W/m at -3 °C increases to 1.27 W/m at 51°C, while for the return pipe the heat leak of 0.46 W/m at -3 °C increases to 0.94 W/m at 51°C. The heat leak increases smoothly with the surface temperature, which can be well reproduced by a formula based on the temperature dependences of the radiative and conductive heat transfers. The heat leak by the conductive heat transfer is discussed based on the experiments and the calculations.
Evaluation of the operation efficiency of implemented highway project
Authors: Ellk Dunya Sahib , Adil Hanan
Published: August 2020

Traffic congestion is a considerable problem that big cities face and has undesirable consequences such as uncomfortable usage of roads, car accidents, worsening of performance of road networks, air pollution and economic issues. Therefore, governments have been planning to solve this problem and reduce the traffic congestion level (1). Recently, it is observed that Baghdad city has suffered from severe daily traffic congestion. The key reasons include the great increase in the number of private cars and the deterioration of public transit services. The planners tend to building new highways, such as overpasses and underpasses, to accommodate the increase in the traffic volume and alleviate congestion. However, it is noted that this problem has been persisted in several locations in Baghdad city even after the operation of the new overpasses and underpasses. It means that the implemented projects have not efficient in achieving their aim. Thus, it has been important to investigate the reasons behind this failure. This study focused on evaluating the efficiency performance of two selected overpasses at the Al-Shaab quarter and at the Bab al-Muadam place as the congestion is still in its highest level there, especially at peak hours. A traffic analysis study was accomplished involving a collection of traffic data in the two locations and analysing them using the HCS2000 program in order to specify the reasons of poor performance. It was found that level of service is F after construction, therefore the paper proposed number of alternative suggestions to develop their performance.
Stability analysis of geosynthically piled foundation earth dam; a case study: Sombar dam
Authors: Akhtarpour Ali , Mahmood Mohammed Sh , Alali Ameer
Published: August 2020

The use of drains in a regular grid and required depth in the soil are reduced the time of drainage process and soil consolidation considerably. Sombar dam is a project to use optimum seawater flow and flood control to provide agricultural water as well as to develop the area under cultivation of the existing dam in Gholaman village as well as the city of Raz in north Khorasan province, Iran. The purpose of this research is assessing the influence of vertical geotextile drainage (length and spacing), for different permeability ratios (ky/kx), on the dam stability during the construction using GeoStudio2012 software. The analysis is performed using models of Mohr-Coulomb and modified cam clay. The results show that there is a significant effect of the drains for the studied parameters. After 24 months with maximum drain depth (24m) and minimum drain spacing (2m) the values of the studied parameters are closer to each other.
Futurity scenario of water resources management in Bahr An-Najaf basin in Iraq
Authors: Omran Hassan Ali , Mahmood Mohammed Sh , Kadhem Ali Abbas
Published: August 2020

By using water resources management techniques for planning, improvement and supply, optimal use of the available water inside Iraq will achieve. This paper focuses on the management of water resources in Bahr Al-Najaf region, Najaf, Iraq for the expected future water resources and demands. These resources and demands are adopted with continued demands from the current situation to study the adequacy of water resource quantities in the study area. The authors try to answer the question that is the resources are enough or must provide other quantities of surface water and groundwater? and what amount? The results of the study indicate that there is a shortage that occurs in the futurity scenario of 55Mm3 and it is related to the tourism sector. The shortage of water quantity of the futurity scenario can be covered by drilling new wells by portion reach to 85%.