bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reversible engineering of topological insulator surface state conductivity through optical excitation
Authors: Xie Faji , Lian Zhen , Zhang Shuai , Wang Tianmeng , Miao Shengnan , Song Zhiyong , Ying Zhe , Pan Xing-Chen , Long Mingsheng , Zhang Minhao , Fei Fucong , Hu Weida , Yu Geliang , Song Fengqi , Kang Ting-Ting , Shi Su-Fei 
Published: January 2021

Abstract
Despite the broadband response, limited optical absorption at a particular wavelength hinders the development of optoelectronics based on Dirac fermions. Heterostructures of graphene and various semiconductors have been explored for this purpose, while non-ideal interfaces often limit the performance. The topological insulator (TI) is a natural hybrid system, with the surface states hosting high-mobility Dirac fermions and the small-bandgap semiconducting bulk state strongly absorbing light. In this work, we show a large photocurrent response from a field effect transistor device based on intrinsic TI Sn–Bi1.1Sb0.9Te2S (Sn-BSTS). The photocurrent response is non-volatile and sensitively depends on the initial Fermi energy of the surface state, and it can be erased by controlling the gate voltage. Our observations can be explained with a remote photo-doping mechanism, in which the light excites the defects in the bulk and frees the localized carriers to the surface state. This photodoping modulates the surface state conductivity without compromising the mobility, and it also significantly modify the quantum Hall effect of the surface state. Our work thus illustrates a route to reversibly manipulate the surface states through optical excitation, shedding light into utilizing topological surface states for quantum optoelectronics.
Kupffer cell-targeting strategy for the protection of hepatic ischemia/reperfusion injury
Authors: Dai Qingqing , Jiang Wei , Liu Hu , Qing Xin , Wang Guobin , Huang Fan , Yang Zhilai , Wang Chunhui , Gu Erwei , Zhao Hongchuan , Zhang Jiqian , Liu Xuesheng 
Published: January 2021

Abstract
The aim of this study is to evaluate the effect of rare earth upconversion nanoparticles (UCNs) on hepatic ischemia reperfusion injury (IRI) and explore its possible mechanism. Hepatic IRI seriously affects the prognosis of patients undergoing liver surgery. Liver-resident Kupffer cells have been reported to promote IRI. Nanomedicines are known to be effective in the treatment of liver diseases, however, Kupffer cell-targeting nanomedicines for the treatment of IRI are yet to be developed. As potential bioimaging nanomaterials, UCNs have been found to specifically deplete Kupffer cells, but the underlying mechanism is unknown. In this study, we found that UCNs specifically depleted Kupffer cells by pyroptosis, while the co-administration of the caspase-1 inhibitor VX-765 rescued the UCN-induced Kupffer cell pyroptosis in mice. Furthermore, the pre-depletion of Kupffer cells by the UCNs significantly suppressed the release of inflammatory cytokines and effectively improved hepatic IRI. The rescue of the pyroptosis of the Kupffer cells by VX-765 abrogated the protective effect of UCNs on the liver. These results suggest that UCNs are highly promising for the development of Kupffer cell-targeting nanomedicines for intraoperative liver protection.
Vertical bounce of a spinning ball
Authors: Cross Rod 
Published: January 2021

Abstract
An experiment is described where three different spinning balls were dropped vertically on a horizontal surface, and the bounce was filmed with a video camera. The change in spin and horizontal speed of each ball was estimated theoretically, using equations familiar to physics students. The experiment provides an extension of the usual student exercise where a non-spinning ball is dropped vertically on a surface to measure the coefficient of restitution.
Characterization of surface roughness by speckle pattern—an experimental approach
Authors: Souza P V S , Rodrigues D P , Silva L da , Huguenin J A O , Balthazar W F 
Published: January 2021

Abstract
Although it originates from the ancient Greeks, optics still arouses a lot of scientific interest, mainly due to the technological innovation associated with it. One of its most interesting applications is related to optical metrology and the characterization of materials through optical techniques. While some of these processes can be explained in a simplified way using a few of the fundamental principles of physics, there are hardly any proposals whose objective is to discuss this topic at a basic level. Accordingly, we present a low-cost experiment that allows the characterization of surface roughness using the fractal dimension of the speckle pattern associated with the light scattered by a surface. For simplicity, the entire activity is adaptable to the most diverse school situations. Moreover, it allows the discussion of many fundamental physics concepts and provides students with an experience similar to that experienced by scientists.
Probabilistic dose prediction using mixture density networks for automated radiation therapy treatment planning
Authors: Nilsson Viktor , Gruselius Hanna , Zhang Tianfang , De Kerf Geert , Claessens Michaël 
Published: January 2021

Abstract
We demonstrate the application of mixture density networks (MDNs) in the context of automated radiation therapy treatment planning. It is shown that an MDN can produce good predictions of dose distributions as well as reflect uncertain decision making associated with inherently conflicting clinical tradeoffs, in contrast to deterministic methods previously investigated in the literature. A two-component Gaussian MDN is trained on a set of treatment plans for postoperative prostate patients with varying extents to which rectum dose sparing was prioritized over target coverage. Examination on a test set of patients shows that the predicted modes follow their respective ground truths well, both spatially and in terms of their dose–volume histograms. A special dose mimicking method based on the MDN output is used to produce deliverable plans and thereby showcase the usability of voxel-wise predictive densities. Thus, this type of MDN may serve to support clinicians in managing clinical tradeoffs and has the potential to improve the quality of plans produced by an automated treatment planning pipeline.
Coupled plasma transport and electromagnetic wave simulation of an ECR thruster
Authors: Sánchez-Villar Álvaro , Zhou Jiewei , Ahedo Eduardo , Merino Mario 
Published: January 2021

Abstract
An electron-cyclotron resonance thruster (ECRT) prototype is simulated numerically, using two coupled models: a hybrid particle-in-cell/fluid model for the integration of the plasma transport and a frequency-domain full-wave finite-element model for the computation of the fast electromagnetic (EM) fields. The quasi-stationary plasma response, fast EM fields, power deposition, particle and energy fluxes to the walls, and thruster performance figures at the nominal operating point are discussed, showing good agreement with the available experimental data. The ECRT plasma discharge contains multiple EM field propagation/evanescence regimes that depend on the plasma density and applied magnetic field that determine the flow and absorption of power in the device. The power absorption is found to be mainly driven by radial fast electric fields at the electron-cyclotron resonance region, and specifically close to the inner rod. Large cross-field electron temperature gradients are observed, with maxima close to the inner rod. This, in turn, results in large localized particle and energy fluxes to this component.
Particle-in-cell simulations of the alpha and gamma modes in collisional nitrogen capacitive discharges
Authors: Kawamura E , Lieberman M A , Lichtenberg A J , Chabert P 
Published: January 2021

Abstract
We perform one-dimensional (1D) particle-in-cell (PIC) simulations to study the α and γ modes in an intermediate pressure 1.6 Torr, 2.5 cm gap capacitive nitrogen discharge driven at 13.56 MHz with current density amplitudes J
0 = 7 to 150 A m−2. In the α-mode, ion-induced secondary electron emission has minimal effects on the discharge equilibrium, while in the γ-mode, it is essential for sustaining the discharge. As in a previous study of a comparable argon discharge, [Kawamura et al 2020, J. Vac. Sci. Technol. A
38, 023003], the nitrogen discharge in the α-mode can be described by a ‘passive bulk’ model in which the ionization is negligible in the central bulk region and is due solely to electron sheath heating. The nitrogen discharge undergoes an α to γ transition in the applied J
0 range, characterized by an increase in density and a decrease in electron temperature, sheath widths and sheath voltages. For the γ-mode, we calculate the scalings of the maximum sheath width s
m and the rf sheath voltage amplitude V
1 with J
0. We compare the PIC results in the α-mode to the passive bulk model (modified for nitrogen), and, in the γ-mode with the expected J
0-V
1 and s
m-V
1 curves. We find good agreement with the simulations in both the α and γ regimes, and the α to γ transition is well predicted by the models.
Correlation between frequency and location on the wafer for terahertz quantum-cascade lasers
Authors: Lü Xiang , Röben Benjamin , Schrottke Lutz , Biermann Klaus , Grahn Holger T 
Published: January 2021

Abstract
We have investigated the emission frequency of terahertz (THz) quantum-cascade lasers (QCLs) as a function of the location on the wafer. The frequency varies due to an inhomogeneous growth rate across the wafer. For three wafers based on GaAs/AlAs heterostructures for lasers with target frequencies of 3.36 and 3.92 THz, we observed a blue shift of the emission frequency from the center to the edge of the wafer. This blue shift is attributed to a decrease of the period length of the QCLs, which can be determined with spectroscopic techniques. The location-dependent period length is used to calculate a position-dependent frequency of the gain maximum for the active region. The correlation of the calculated frequencies with the emission frequencies of lasers fabricated from different locations on the wafer allows us to establish an effective method for the fabrication of THz QCLs emitting at a particular target frequency.
Development of spacer warp knitted thermoelectric generators
Authors: Dallmann Anke , Franz Christian , Hoffmann Gerald , Cherif Chokri 
Published: January 2021

Abstract
The research presented in this paper was aimed at developing spacer warp knitted thermoelectric generators (TEGs), which can generate electrical current from waste heat. Hence, this paper introduces a structural design approach and a calculation model in addition to describing the manufacturing of prototypes and analyses on their basic functionality regarding thermoelectric power generation. Wires as well as wire strands of iron and constantan can be used for knitting on a double bar raschel machine. Wires can be connected to a thermocouple (TC) by means of various spacer warp knitting patterns while using the feed system of the spacer yarn for the wires. The friction locking electrical contacting of several TC, thus forming an applicable TEG, was achieved by sewing together silver plated copper wire strands. A large wire cross section, clear separation of iron and con-stantan wires in the knitted fabric, and consistently high temperature difference between the TEG surfaces produce a constant thermoelectric voltage. The maximum voltage depends on the number of TC, the material properties, and the temperature difference. By reducing the internal resistance of the TEG, electric power can be increased.
Simultaneous double ionization of C60 molecules in single-cycle pulses
Authors: Schubert I , Bart G , Brabec T 
Published: January 2021

Abstract
We theoretically investigate simultaneous double ionization of C60 Buckminsterfullerene clusters within the strong field approximation, taking into account two-body effects like Coulomb blocking. Our analysis suggests that for infrared single-cycle pulses, simultaneous double ionization becomes comparable in magnitude to sequential double ionization. Additionally, estimates show that Coulomb blocking weakens with increasing cluster size and field strength.
Cortical responses to prosthetic retinal stimulation are significantly affected by the light-adaptive state of the surrounding normal retina
Authors: Arens-Arad Tamar , Lender Rivkah , Farah Nairouz , Mandel Yossi 
Published: January 2021

Abstract

Objective. Restoration of central vision loss in patients with age-related macular degeneration (AMD) by implanting a retinal prosthesis is associated with an intriguing situation wherein the central prosthetic vision co-exists with natural normal vision. Of major interest are the interactions between the prosthetic and natural vision. Here we studied the effect of the light-adaptive state of the normal retina on the electrical visual evoked potentials (VEPs) arising from the retinal prosthesis. Approach. We recorded electrical VEP elicited by prosthetic retinal stimulation in wild-type rats implanted with a 1 mm photovoltaic subretinal array. Cortical responses were recorded following overnight dark adaption and compared to those recorded following bleaching of the retina by light (520 nm) at various intensities and durations. Main results. Compared to dark-adapted responses, bleaching induced a 2-fold decrease in the prosthetic cortical response, which returned to the dark-adapted baseline within 30 min to several hours, depending on the degree of bleaching. This reduction was neither observed in Royal College of Surgeons (RCS) rats with a degenerated photoreceptor layer nor following intravitreal injection of a GABAa receptor blocker (bicuculine), suggesting the involvement of photoreceptors and a GABAa-mediated mechanism. Significance. These findings show a robust effect of the retinal light-adaptive state on the obtained prosthetic responses. If a similar effect is found in humans, this will have immediate implications on the design of prosthetic devices, where both natural and prosthetic vision co-exist, such as in AMD patients receiving a photovoltaic retinal implant. Similarly, standardization of the retinal light-adaptive state in prosthetic clinical trials should be considered.
Coordinate method for determining position in geodetic monitoring of cracks
Authors: Kuzin A A , Palkin P O 
Published: January 2021

Abstract
The article presents the coordinate method of monitoring the cracks of buildings and engineering constructions. All the methods that are used according to regulatory documents were analyzed, and their advantages and drawbacks were described. The conditions of real measurement were simulated using a total station. The method of achieving accuracy increase was elaborated and mathematical analysis was made. The accuracy of this method was determined. Based on this analysis, it was concluded that surveying methods, among others, could be used to monitor cracks of buildings and engineering constructions.
Improving energy efficiency in well construction through the use of hydrocarbon-based muds and muds with improved lubricating properties
Authors: Nutskova M V , Dvoynikov M V , Budovskaya M E , Sidorov D A , Pantyukhin A A 
Published: January 2021

Abstract
During the construction of directional wells in spatially curved sections of the barrel, large contact loads and huge resistance to the movement of the drill string during lifting can occur, which leads to increased wear of the drill pipes and high energy costs. One of the directions for increasing the energy efficiency of drilling such wells was the reduction of friction at the metal-metal, metal-rock, and metal-filter cake boundaries. This result can be achieved by introducing special lubricating additives or by switching to a hydrocarbon solution during drilling. The article presents the study of drilling fluids with the introduction of lubricating additives on a lubricity tester Fann EP / Lubricity Tester Model 212, a device for determining the coefficient of clay cake KTK-2, a rotary viscometer Fann 35SA, pH meter Crison GLP 21 to reduce the coefficient of friction of a pair “metal – metal” in a clay solution, which amounted to 70-75%, in an aqueous solution - up to 65%. The optimal concentration of the additive according to the study in different drilling fluids was about 1.5-2%. The results of a study of the effect of the speed and time of mixing a hydrocarbon-based solution during its preparation on the electrostability of the emulsion obtained are carried out on a BVD device, which showed a significant increase in the stability of the washing liquid to 24%, which leads to a decrease in the number of complications associated with pipe wear and a decrease torque when rotating the column.
Experimental and Implementation of Robust Control Via Floating Air Levitation and Balancing Rotary Inverted Pendulum
Authors: Howimanporn S , Chookaew S , Chaiyaporn S 
Published: January 2021

Abstract
This paper presents the implementation of robust control by using Programmable Logic Controller (PLC) for studying the behaviour of floating and balancing system. Floating Air Levitation system (FAL) and rotary inverted pendulum system (RIPs) module were designed and developed as the actual plant to investigate the performance of designed controller with the nonlinear systems. The objective of controller for FALs is to keep the height of a ball in the tube as the set point precisely, by adjusting the velocity of air flowing passing through the ball. For RIP, the objective is to stabilize the pendulum in upright position. Both plants can provide either the displacement or angular position by various type of sensors: ultrasonic and encoder. In this work, Proportional, Integral and Derivative (PID) and sliding mode controller (SMC) were implemented in OMRON NX1P PLC by using SYSMAC studio software for monitoring and control. The experimental results showed the comparison of PID and SMC performance. SMC presented a robustness response and low oscillating error depend on controller.
Effect of negative surface energy on nanocrystal morphology
Authors: Lai Fuming 
Published: January 2021

Abstract
One-dimensional materials, such as nanowires, nanotubes, and nanobelts, exhibit special optical and electrical properties owing to their high specific surface area and quantum confinement effect, and thus have wide application prospects. However, the surface energy of one-dimensional materials has caused some confusion in the past. In this work, we develop a model based on the thermodynamics, which can be used to explicitly predict the evolution of morphologies in different environments given its orientation-dependent surface free energy is negative. It is found that the negative surface energy would cause the increase of the interface and induce the bulk phase to nanowires. Our computations agree well with previous studies where applicable.
Numerical simulation analysis on settlement of backfill materials under traffic load
Authors: Zhang Jie , Hu Xinmin 
Published: January 2021

Abstract
In order to solve the problem of settlement cracks around the manhole, the finite element software MARC is used to simulate the settlement of the manhole and the pavement around the manhole, and the influence of different backfill materials (sand, clay, self-made backfill material) on the settlement difference between the manhole and the pavement is analysed. The results show that the performance of self-made backfill material is better than that of traditional backfill material. It is of great significance to ensure the quality of backfill, reduce the settlement of pavement and protect the urban environment.
Certification of Radome Lightning Direct Effects Protection
Authors: Fei Qin , Ying Wu 
Published: January 2021

Abstract
Composite material is used more and more in airplanes year after year. The electrical conductivity of composite material structure is poorer than metal structure, so appropriate lightning protection measures should be adopted to shunt lightning current when composite structure suffering lightning strike, and the harmful consequence will be minimized. The paper takes radome as an example, which is located at nose area liable to suffer lightning strike, introduces radome lightning protection measures, and according to lightning direct effect verification process, discusses on means of compliance, plans high voltage strike attachment test and high current physical damage test of radome. It provides reference for airworthiness verification for radome.
Contact polarizations and associated metrics in geometric thermodynamics
Authors: Lopez-Monsalvo C S , Nettel F , Pineda-Reyes V , Escamilla-Herrera L F 
Published: January 2021

Abstract
In this work we show that a Legendre transformation is nothing but a mere change of contact polarization from the point of view of contact geometry. Then, we construct a set of Riemannian and pseudo-Riemannian metrics on a contact manifold by introducing almost contact and para-contact structures and we analyze their isometries. We show that it is not possible to find a class of metric tensors which fulfills two properties: on the one hand, to be polarization independent i.e. the Legendre transformations are the corresponding isometries and, on the other, that it induces a Hessian metric into the corresponding Legendre submanifolds. This second property is motivated by the well known Riemannian structures of the geometric description of thermodynamics which are based on Hessian metrics on the space of equilibrium states and whose properties are related to the fluctuations of the system. We find that to define a Riemannian structure with such properties it is necessary to abandon the idea of an associated metric to an almost contact or para-contact structure. We find that even extending the contact metric structure of the thermodynamic phase space the thermodynamic desiderata cannot be fulfilled.
On pro-2 identities of 2×2 linear groups
Authors: Ben-Ezra David El-Chai , Zelmanov Efim 
Published: January 2021

Let

F
^

\hat {F}

be a free pro-

p
p

non-abelian group, and let

Δ
\Delta

be a commutative Noetherian complete local ring with a maximal ideal

I
I

such that

c
h
a
r

(
Δ

/

I
)
=
p
>
0

\mathrm {char}(\Delta /I)=p>0

. Zubkov [Sibirsk. Mat. Zh. 28 (1987), pp. 64–69] showed that when

p
≠
2

p\neq 2

, the pro-

p
p

congruence subgroup
\[

G

L

2

1

(
Δ
)
=
ker
⁡
(
G

L

2

(
Δ
)

⟶

Δ
→
Δ

/

I

G

L

2

(
Δ

/

I
)
)

GL_{2}^{1}(\Delta )=\ker (GL_{2}(\Delta )\overset {\Delta \to \Delta /I}{\longrightarrow }GL_{2}(\Delta /I))

\]
admits a pro-

p
p

identity, i.e., there exists an element

1
≠
w
∈

F
^

1\neq w\in \hat {F}

that vanishes under any continuous homomorphism

F
^

→
G

L

2

1

(
Δ
)

\hat {F}\to GL_{2}^{1}(\Delta )

.

In this paper we investigate the case

p
=
2

p=2

. The main result is that when

c
h
a
r

(
Δ
)
=
2

\mathrm {char}(\Delta )=2

, the pro-

2
2

group

G

L

2

1

(
Δ
)

GL_{2}^{1}(\Delta )

admits a pro-

2
2

identity. This result was obtained by the use of trace identities that originate in PI-theory.
Pyoderma Gangrenosum: A Rare Disease With Dire Consequences in Facial Aesthetic Surgery Patients
Authors: Thornburg Danielle A , Aime Victoria , James Sheridan , Gupta Nikita , Bernard Robert , Johnson Martin L 
Published: January 2021

Abstract
Pyoderma gangrenosum (PG) is a rare, inflammatory dermatologic condition characterized by painful cutaneous ulcerations. Herein, we describe the third documented case of PG arising in an elective plastic surgery patient who had undergone an otherwise uncomplicated facelift. We describe the course of her diagnosis and management of PG, which involved her face and neck and then progressed to her lower extremities. Although the etiology remains unknown, PG often arises in a host with another autoimmune disease. In the case described, the patient was diagnosed with an immunoglobulin A gammopathy shortly after she developed PG. Following the case report, the pathogenesis, diagnosis, and treatment strategy of PG is briefly reviewed.
Level of Evidence: 5