bluuebunny/crossref_metadata_2025_split huggingface dataset:
The sacrificial adaptor protein Skp functions to remove stalled substrates from the β-barrel assembly machine
Authors: Combs Ashton N. , Silhavy Thomas J. 
Published: December 2021

Significance
The outer membrane (OM) of gram-negative bacteria acts as a robust permeability barrier to enable cell survival in a wide variety of harsh environments. Crucial to OM integrity are β-barrel outer membrane proteins (OMPs) that are assembled into the membrane by the broadly conserved β-barrel assembly machine (Bam) complex. Here, we identify specific roles for the periplasmic chaperone Skp in functioning as a sacrificial adaptor protein to remove stalled substrates from the Bam complex, imposing an active quality control mechanism that ensures efficient assembly of nascent OMPs into the OM. This work identifies the molecular mechanism of the Skp/DegP functional relationship and clarifies the long-standing paradox of how substrate release from the high-affinity, long-lived Skp–OMP complex is achieved in vivo.
Analyses of defect distributions in ZnO varistors based on the Jonscher’s universal power law and the Dissado–Hill model
Authors: Zhao Xia , Guo Men , Wen Yuandong , Shi Weidong , Zhang Boyu , Li Yupeng , Wen Ran 
Published: December 2021

Abstract
The defect distributions in ZnO varistors mixed with Bi2O3, NiO, MnCO3, Co2O3, and SiO2 after doping Sb2O3 were investigated, based on the Jonscher’s universal power law and the Dissado–Hill model. The microstructures were investigated using x-ray diffractometer, scanning electron microscope, energy dispersive spectrometer, and x-ray photoelectron spectrometer. The capacitance–voltage (C–V) method was utilized to obtain the parameters of the double Schottky barrier. The dielectric spectra were analyzed to extract the parameters of defect distribution. The current density–electric field (J–E) characteristics were measured to obtain the parameters of electrical properties. We found that with increasing Sb2O3 content, the ZnO grain size distribution become more homogeneous in the Sb2O3-doped ZnO varistors; the density

Zn

i

×

is decreased; except for less homogeneous

V

O

×

, more homogeneous distributions of

Zn

i

∙

in the depletion layers and the extrinsic defects at the interfaces are achieved in the Sb2O3-doped ZnO varistors. Therefore, the enhancement in the electrical properties was achieved by doping Sb2O3 due to the increased number of active grain boundaries per unit volume, i.e. the increased breakdown field and nonlinear coefficient, and the decreased leakage current density. The results of this study suggest that the Jonscher’s universal power law and the Dissado–Hill model can be effectively used to analyze defect distributions in varistor ceramics.
Characterization of plasma catalytic decomposition of methane: role of atomic O and reaction mechanism
Authors: Li Yudong , Jiang Jingkai , Hinshelwood Michael , Zhang Shiqiang , Bruggeman Peter J , Oehrlein Gottlieb S 
Published: December 2021

Abstract
In this work, we investigated atmospheric pressure plasma jet (APPJ)-assisted methane oxidation over a Ni-SiO2/Al2O3 catalyst. We evaluated possible reaction mechanisms by analyzing the correlation of gas phase, surface and plasma-produced species. Plasma feed gas compositions, plasma powers, and catalyst temperatures were varied to expand the experimental parameters. Real-time Fourier-transform infrared spectroscopy was applied to quantify gas phase species from the reactions. The reactive incident fluxes generated by plasma were measured by molecular beam mass spectroscopy using an identical APPJ operating at the same conditions. A strong correlation of the quantified fluxes of plasma-produced atomic oxygen with that of CH4 consumption, and CO and CO2 formation implies that O atoms play an essential role in CH4 oxidation for the investigated conditions. With the integration of APPJ, the apparent activation energy was lowered and a synergistic effect of 30% was observed. We also performed in-situ diffuse reflectance infrared Fourier-transform spectroscopy to analyze the catalyst surface. The surface analysis showed that surface CO abundance mirrored the surface coverage of CH
n
at 25 °C. This suggests that CH
n
adsorbed on the catalyst surface as an intermediate species that was subsequently transformed into surface CO. We observed very little surface CH
n
absorbance at 500 °C, while a ten-fold increase of surface CO and stronger CO2 absorption were seen. This indicates that for a nickel catalyst at 500 °C, the dissociation of CH4 to CH
n
may be the rate-determining step in the plasma-assisted CH4 oxidation for our conditions. We also found the CO vibrational frequency changes from 2143 cm−1 for gas phase CO to 2196 cm−1 for CO on a 25 °C catalyst surface, whereas the frequency of CO on a 500 °C catalyst was 2188 cm−1. The change in CO vibrational frequency may be related to the oxidation of the catalyst.
A novel two-step strategy to fabricate phase-pure SnS photoelectrodes with tunable conductivity: formation mechanism and photoelectrochemical properties
Authors: Zhang Wenwan , Cheng Yufei , Zhao Junfeng , Li Qiujie , Wang Jiawei , Zhu Jinyi , Miao Hui , Hu Xiaoyun 
Published: December 2021

Abstract
Tin monosulfide (SnS) is a narrow band gap semiconductor for visible-light harvesting, however the easy formation of secondary phases such as Sn2S3 and SnS2 severely restricts its photoelectrochemical (PEC) properties. Herein, we propose a novel two-step strategy to fabricate phase-pure SnS photoelectrodes with tunable conductivity on Ti foil substrate and carefully investigated the formation mechanism and PEC properties. The tunable conductivity is determined by Na2SO4 pretreatment before annealing, which is supported by energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, and electron paramagnetic resonance characterizations. Na+ adsorbed to the edge of the precursor SnS2 nanosheets forming a dangling bond adsorption will protect S2− against reaction with the trace oxygen in the chemical vapor deposition system within a certain temperature range (<525 °C), thereby reducing the generation of S vacancies to adjust the S/Sn ratio and further regulate the conductivity type. Moreover, the anodic photocurrent density of SnS thin films was about 0.32 mA cm−2 at 1.23 V vs reversible hydrogen electrode (RHE) with the separation and injection efficiency of 1.22% and 72.78% and a maximum cathodic photocurrent density reaching approximately −0.36 mA cm−2 at 0 V vs RHE with the separation and injection efficiency 1.15% and 5.44% respectively. The method shown in this work provides an effective approach to control the electrical conductivity of SnS thin films with considerable photocurrent response for phase-pure SnS.
A higher-order moment matching based fine-grained adversarial domain adaptation method for intelligent bearing fault diagnosis
Authors: Wang Rui , Huang Weiguo , Shi Juanjuan , Wang Jun , Shen Changqing , Zhu Zhongkui 
Published: December 2021

Abstract
Due to the discrepancy in data distribution caused by the time-varying working conditions, intelligent diagnostic methods fail to achieve accurate fault classification in engineering scenarios. This paper presents a novel higher-order moment matching-based adversarial domain adaptation method (HMMADA) for intelligent bearing fault diagnosis. First, a deep one-dimensional convolution neural network is constructed as the feature extractor to learn the discriminative features of each category through different domains. Then, the distribution discrepancy across domains is significantly reduced by using joint higher-order moment statistics (HMS) and adversarial learning. In particular, HMS integrates the first-order and second-order statistics into a unified framework and achieves a fine-grained distribution adaptation between different domains. Finally, the feasibility and effectiveness of HMMADA are validated by several transfer experiments constructed on two different bearing datasets. The results demonstrate that HMS is more effective than lower-order statistics.
Outlier removal method for the refinement of optically measured displacement field based on critical factor least squares and subdomain division
Authors: Wang Bo , Sun Chen , Zhang Keming , Chen Jubing 
Published: December 2021

Abstract
As a representative type of outlier, abnormal data in displacement measurement has often inevitably occurred in full-field optical metrology and significantly affected further evaluation, especially when calculating the strain field by differencing the displacement. In this study, an outlier removal method is proposed which can recognize and remove the abnormal data in an optically measured displacement field. An iterative critical factor least squares (CFLS) algorithm is developed which distinguishes the distance between the data points and the least squares plane to identify the outliers. A successive boundary point algorithm is proposed to divide the measurement domain to improve the applicability and effectiveness of the CFLS algorithm. The feasibility and precision of the proposed method are discussed in detail through simulations and experiments. The results show that the outliers are reliably recognized and the precision of the strain estimation is greatly improved by using these methods.
Piezoelectric Nanogenerators based on Lead Zirconate Titanate nanostructures: an insight into the effect of potential barrier and morphology on the output power generation
Authors: Hazra Snehamoyee , Sengupta Subhamita , Ratha Soumyaranjan , Ghatak Ankita , Raychaudhuri A K , Ghosh Barnali 
Published: December 2021

Abstract
The high internal resistance of the perovskite materials used in Nanogenerators (NGs) lowers the power generation. It severely restricts their application for mechanical energy harvesting from the ambient source. In this work, we demonstrate a flexible Piezoelectric NG (PENG) with an improved device structure. Hydrothermally grown one-dimensional Lead Zirconate Titanate (Pb(ZrTi)O3) of different morphologies are used as the generating material. The morphology of the PZT nanostructures, engineered from nanoparticles to needle-shaped nanowires to increase the surface to volume ratio, provides effective mechanical contact with the electrode. The reduction of the internal resistance of the PENG has been achieved by two ways: (i) fabrication of interdigitated electrodes (IDE) to increase the interfacial polarization and (ii) lowering of Schottky barrier height (SBH) at the junction of the PZT nanostructure and the metal electrode by varying the electrode materials of different work functions. We find that lowering of the SBH at the interface contributes to an increased piezo voltage generation. The flexible nano needles-based PENG can deliver output voltage 9.5 V and power density 615 μW cm−2 on application low mechanical pressure (∼1 kPa) by tapping motion. The internal resistance of the device is ∼0.65 MΩ. It can charge a 35 μF super-capacitor up to 5 V within 20 s. This study provides a systematic pathway to solve the bottlenecks in the piezoelectric nanogenerators due to the high internal resistance.
Experimental analysis of tip vibrations at higher eigenmodes of QPlus sensors for atomic force microscopy
Authors: Ruppert Michael G , Martin-Jimenez Daniel , Yong Yuen K , Ihle Alexander , Schirmeisen André , Fleming Andrew J , Ebeling Daniel 
Published: December 2021

Abstract
QPlus sensors are non-contact atomic force microscope probes constructed from a quartz tuning fork and a tungsten wire with an electrochemically etched tip. These probes are self-sensing and offer an atomic-scale spatial resolution. Therefore, qPlus sensors are routinely used to visualize the chemical structure of adsorbed organic molecules via the so-called bond imaging technique. This is achieved by functionalizing the AFM tip with a single CO molecule and exciting the sensor at the first vertical cantilever resonance mode. Recent work using higher-order resonance modes has also resolved the chemical structure of single organic molecules. However, in these experiments, the image contrast can differ significantly from the conventional bond imaging contrast, which was suspected to be caused by unknown vibrations of the tip. This work investigates the source of these artefacts by using a combination of mechanical simulation and laser vibrometry to characterize a range of sensors with different tip wire geometries. The results show that increased tip mass and length cause increased torsional rotation of the tuning fork beam due to the off-center mounting of the tip wire, and increased flexural vibration of the tip. These undesirable motions cause lateral deflection of the probe tip as it approaches the sample, which is rationalized to be the cause of the different image contrast. The results also provide a guide for future probe development to reduce these issues.
Insight into the stacking and the species-ordering dependences of interlayer bonding in SiC/GeC polar heterostructures
Authors: Tasnim Kazi Jannatul , Alharbi Safia Abdullah R , Musa Md Rajib Khan , Lovell Simon Hosch , Akridge Zachary Alexander , Yu Ming 
Published: December 2021

Abstract
Two-dimensional (2D) polar materials experience an in-plane charge transfer between different elements due to their electron negativities. When they form vertical heterostructures, the electrostatic force triggered by such charge transfer plays an important role in the interlayer bonding beyond van der Waals (vdW) interaction. Our comprehensive first principle study on the structural stability of the 2D SiC/GeC hybrid bilayer heterostructure has found that the electrostatic interlayer interaction can induce the π–π orbital hybridization between adjacent layers under different stacking and out-of-plane species ordering, with strong hybridization in the cases of Si–C and C–Ge species orderings but weak hybridization in the case of the C–C ordering. In particular, the attractive electrostatic interlayer interaction in the cases of Si–C and C–Ge species orderings mainly controls the equilibrium interlayer distance and the vdW interaction makes the system attain a lower binding energy. On the contrary, the vdW interaction mostly controls the equilibrium interlayer distance in the case of the C–C species ordering and the repulsive electrostatic interlayer force has less effect. Interesting finding is that the band structure of the SiC/GeC hybrid bilayer is sensitive to the layer-layer stacking and the out-of-plane species ordering. An indirect band gap of 2.76 eV (or 2.48 eV) was found under the AA stacking with Si–C ordering (or under the AB stacking with C–C ordering). While a direct band gap of 2.00–2.88 eV was found under other stacking and species orderings, demonstrating its band gap tunable feature. Furthermore, there is a charge redistribution in the interfacial region leading to a built-in electric field. Such field will separate the photo-generated charge carriers in different layers and is expected to reduce the probability of carrier recombination, and eventually give rise to the electron tunneling between layers.
Polyaniline coating enables electronic structure engineering in Fe3O4 to promote alkaline oxygen evolution reaction
Authors: Zou Yang , Huang Yuan , Jiang Li-Wen , Indra Arindam , Wang Yongqing , Liu Hong , Wang Jian-Jun 
Published: December 2021

Abstract
The electronic structure of active sites is of importance for catalysts to achieve an optimized interaction with the intermediates. In this study, a unique organic–inorganic hybrid oxygen evolution reaction electrocatalyst composed of electrochemically inactive conducting polyaniline (PANI) and non-precious Fe-based oxide Fe3O4 is presented. PANI molecules were in situ loaded on Fe3O4 nanoparticles through an efficient and simple process under mild conditions. The electronic structure of Fe3O4 was modulated by creating a strong interaction with PANI molecules, leading to enhanced activity and stability of the catalyst to achieve 10 mA cm−2 geometrical current density at overpotential of 265 mV in 1 M aqueous KOH solution. This work demonstrates that a highly efficient electrocatalyst can be achieved by molecular modification and provides a novel strategy for the optimization of the inactive non-precious catalysts.
An experiment design for schools to demonstrate the Maxwell distribution
Authors: Grebenev Igor V , Kazarin Petr V , Lebedeva Olga V 
Published: December 2021

Abstract
The article describes a new version of a demonstration experiment for the Maxwell distribution. In the first part students analyse the applicability of the Gaussian distribution to the projection of the particle velocities in the suggested experiment. Further, students observe two-dimensional distribution of particles by the modulus of velocity in a mechanical demonstration model and compare the results with theoretical provisions. Demonstration of the two-dimensional version of the Maxwell distribution for particle interaction allows students to independently derive formulas for the three-dimensional Maxwell distribution for particles in an ideal gas. The use of the suggested demonstration ensures active engagement in fundamentally important physical content.
Controllable chiral Majorana modes by noncollinear magnetic configuration in a topological Josephson junction
Authors: Li M Y , Yu Q Y , Hu J G , Liu T M , Tao Y C , Wang J 
Published: December 2021

Abstract
We theoretically present controllable chiral Majorana modes (CMMs) by noncollinear magnetic configuration in a Josephson junction on a topological insulator, where two ferromagnetic insulators (FIs) are sandwiched in between two superconductors (SCs). It is shown that an additional phase shift is induced by the different chiralities of the CMMs at the two FI/SC interfaces. Its magnitude is determined by the misorientation angle θ, which can result in the 0 − π state transition and ϕ
0 supercurrent. Particularly, due to the selective equal spin Andreev reflection, the coexistence of fully spin-polarized spin-triplet and -singlet correlations is exhibited. However, for the two magnetizations only along the y-axis, there exist no additional phase shift and the 100% supercurrent magnetoresistance can be exhibited. The results can be employed to not only identify the topological SCs but also design a perfect topological supercurrent spin valve device.
Theory of quasi-exact fault-tolerant quantum computing and valence-bond-solid codes
Authors: Wang Dong-Sheng , Wang Yun-Jiang , Cao Ningping , Zeng Bei , Laflamme Raymond 
Published: December 2021

Abstract
In this work, we develop the theory of quasi-exact fault-tolerant quantum (QEQ) computation, which uses qubits encoded into quasi-exact quantum error-correction codes (‘quasi codes’). By definition, a quasi code is a parametric approximate code that can become exact by tuning its parameters. The model of QEQ computation lies in between the two well-known ones: the usual noisy quantum computation without error correction and the usual fault-tolerant quantum computation, but closer to the later. Many notions of exact quantum codes need to be adjusted for the quasi setting. Here we develop quasi error-correction theory using quantum instrument, the notions of quasi universality, quasi code distances, and quasi thresholds, etc. We find a wide class of quasi codes which are called valence-bond-solid codes, and we use them as concrete examples to demonstrate QEQ computation.
Protocol for generation of high-dimensional entanglement from an array of non-interacting photon emitters
Authors: Bell Thomas J , Bulmer Jacob F F , Jones Alex E , Paesani Stefano , McCutcheon Dara P S , Laing Anthony 
Published: December 2021

Abstract
Encoding high-dimensional quantum information into single photons can provide a variety of benefits for quantum technologies, such as improved noise resilience. However, the efficient generation of on-demand, high-dimensional entanglement was thought to be out of reach for current and near-future photonic quantum technologies. We present a protocol for the near-deterministic generation of N-photon, d-dimensional photonic Greenberger–Horne–Zeilinger (GHZ) states using an array of d non-interacting single-photon emitters. We analyse the impact on performance of common sources of error for quantum emitters, such as photon spectral distinguishability and temporal mismatch, and find they are readily correctable with time-resolved detection to yield high fidelity GHZ states of multiple qudits. When applied to a quantum key distribution scenario, our protocol exhibits improved loss tolerance and key rates when increasing the dimensionality beyond binary encodings.
In situ measurements of low energy D plasma-driven permeation through He pre-damaged W
Authors: Li Xue-Chun , Zhou Hai-Shan , Liu Hao-Dong , Wang Lu , Luo Guang-Nan 
Published: December 2021

Abstract
Experiments concerning the effect of helium (He) plasma exposure on deuterium (D) plasma-driven permeation through tungsten (W) foils in a linear plasma facility have been performed. 0.05 mm thick W foils were exposed to ∼2 × 1020 m−2 s−1 He plasma with various fluences at 883 K. After He irradiating, D permeation tests were performed for the samples and retention was also measured by high-resolution thermal desorption spectroscopy. It was observed that He pre-irradiation resulted in a significant reduction of D permeation and retention in W. Microstructure observation indicated that the surfaces of the samples after He irradiation turned rough and He nanobubbles were formed near the surface. Defective structures including He nanobubbles likely enhance D reemission and accordingly reduce the permeation and retention in He pre-irradiated W.
Improved scaling law for the prediction of deuterium retention in beryllium co-deposits
Authors: Založnik Anže , Baldwin Matthew J. , Doerner Russell P. , De Temmerman Gregory , Pitts Richard A. 
Published: December 2021

Abstract
Hydrogen isotope co-deposition with Be eroded from the first wall is expected to be the main fusion fuel retention mechanism in ITER. Since good fuel accounting is crucial for economic and safety reasons, reliable predictions of hydrogen isotope retention are needed. This study builds upon the well-established empirical De Temmerman scaling law De Temmerman et al (2008 Nucl. Fusion
48 075008) that predicts D/Be ratios in co-deposited layers based on deposition temperature, deposition rate, and deuterium particle energy. Expanding the data used in the original development of the scaling law with an additional dataset obtained with more recent measurements using a different technique to the original De Temmerman approach, allows us to obtain new values for free parameters and improve the prediction capabilities of the new scaling law. In an effort to improve the model even further, scaling with D2 background pressure was included and a new two-term model derived, describing D retention in low- and high-energy traps separately.
Beryllium erosion and redeposition in ITER H, He and D–T discharges
Authors: Romazanov J. , Kirschner A. , Brezinsek S. , Pitts R.A. , Borodin D. , Rode S. , Navarro M.X. , Schmid K. , Veshchev E. , Neverov V.S. , Kukushkin A.B. , Alekseev A.G. , Linsmeier Ch. 
Published: December 2021

Abstract
The Monte-Carlo code ERO2.0 was used to simulate steady-state erosion and transport of beryllium (Be) in the ITER main chamber. Various plasma scenarios were tested, including a variation of the main species (hydrogen, deuterium, helium), plasma conditions (density, temperature, flow velocity) and magnetic configurations. The study provides valuable predictions for the Be transport to the divertor, where it is expected to be an important contributor to dust formation and fuel retention due to build-up of co-deposited layers. The Be gross and net erosion rates provided by this study can help identifying first wall regions with potentially critical armour lifetime.