bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of three approaches used for respiratory measurement in healthy subjects
Authors: Duan Xiaojuan , Song Xin , Yang Caidie , Li Yunchi , Wei Liang , Gong Yushun , Li Yongqin 
Published: September 2023

Abstract

Objective. Respiration is one of the critical vital signs of human health status, and accurate respiratory monitoring has important clinical significance. There is substantial evidence that alterations in key respiratory parameters can be used to determine a patient’s health status, aid in the selection of appropriate treatments, predict potentially serious clinical events and control respiratory activity. Although various approaches have been developed for respiration monitoring, no definitive conclusions have been drawn regarding the accuracy of these approaches because each has different advantages and limitations. In the present study, we evaluated the performance of three non-invasive respiratory measurement approaches, including transthoracic impedance (IMP), surface diaphragm electromyography-derived respiration (EMGDR) and electrocardiogram-derived respiration (ECGDR), and compared them with the direct measurement of airflow (FLW) in 33 male and 38 female healthy subjects in the resting state. Approach. The accuracy of six key respiratory parameters, including onset of inspiration (Ion
), onset of expiration (Eon
), inspiratory time (It
), expiratory time (Et
), respiratory rate (RR) and inspiratory–expiratory ratio (I:E), measured from the IMP, EMGDR and ECGDR, were compared with those annotated from the reference FLW. Main results. The correlation coefficients between the estimated inspiratory volume and reference value were 0.72 ± 0.20 for IMP, 0.62 ± 0.23 for EMGDR and 0.46 ± 0.21 for ECGDR (p < 0.01 among groups). The positive predictive value and sensitivity for respiration detection were 100% and 100%, respectively, for IMP, which were significantly higher than those of the EMGDR (97.2% and 95.5%, p < 0.001) and the ECGDR (96.9% and 90.0%, p < 0.001). Additionally, the mean error (ME) for Ion
, Eon
, It
, Et
and RR detection were markedly lower for IMP than for EMGDR and ECGDR (p < 0.001). Significance. Compared with EMGDR and ECGDR, the IMP signal had a higher positive predictive value, higher sensitivity and lower ME for respiratory parameter detection. This suggests that IMP is more suitable for dedicated respiratory monitoring and parameter evaluation.
Evanescent coupling of nonlinear integrated cavities for all-optical reservoir computing
Authors: Boikov I K , Brunner D , De Rossi A 
Published: September 2023

Abstract
We consider theoretically a network of evanescently coupled optical microcavities to implement a space-multiplexed optical neural network in an integrated nanophotonic circuit. Nonlinear photonic network integrations based on evanescent coupling ensure a highly dense integration, reducing the chip footprint by several orders of magnitude compared to commonly used designs based on long waveguide connections while allowing the processing of optical signals with bandwidth in a practical range. Different nonlinear effects inherent to such microcavities are studied for realizing an all-optical autonomous computing substrate based on the reservoir computing concept, and their contribution to computing performance is demonstrated. We provide an in-depth analysis of the impact of basic microcavity parameters on the computational metrics of the system, namely, the dimensionality and the consistency. Importantly, we find that differences between frequencies and bandwidths of supermodes formed by the evanescent coupling are the determining factor of the reservoir’s dimensionality and scalability. The network’s dimensionality can be improved with frequency-shifting nonlinear effects such as the Kerr effect, while two-photon absorption has the opposite effect. Finally, we demonstrate in simulation that the proposed reservoir is capable of solving the Mackey–Glass prediction and the optical signal recovery tasks at gigahertz timescale.
Temperature-dependent dielectric properties of p-n heterojunction diodes based on hydrothermally synthesized ZnO nanostructures
Authors: Çağırtekin Ali Orkun , Ajjaq Ahmad , Barin Özlem , Acar Selim 
Published: September 2023

Abstract
In this study, the effect of coating p-Si substrates with a pure ZnO layer using the hydrothermal reaction method on the dielectric parameters was reported. The studied dielectric properties of the ZnO/p-Si structure include dielectric constant (ε′), dielectric loss (ε″), ac electrical conductivity (σ
AC), and real and imaginary electrical modulus (M′, M″). These properties were investigated using experimental capacitance-frequency (C-f) and conductivity-frequency (G-f) measurements in a frequency range of 20 Hz-1 MHz and a temperature range of 300-420 K. Experimental results show that dielectric parameters are strongly frequency- and temperature-dependent. The dielectric constant showed an increase of about 11 times in the investigated temperature range. At the same time, AC electrical conductivity increased with increasing frequency and temperature. In addition, the electrical modulus was examined, and peaks were observed in M″ values. It was observed that the peaks shifted to the high-frequency region with the increase in temperature. The activation energies were also calculated from the conductivity parameters and a decrease was observed in the activation energies as the frequency increased. Regardless of temperature and frequency, the higher dielectric loss of the fabricated diode compared to its dielectric constant can be advantageous for certain heating or electromagnetic absorption applications.
Pulse electromagnetic flow of Jeffrey fluid in parallel plate microchannels
Authors: Li Dongsheng , Li Kun , Li Haibin 
Published: September 2023

Abstract
This paper investigates the pulse electromagnetic flow of a Jeffery fluid between parallel plate microchannels, where the pulse is considered as a relatively stable and common rectangular pulse. The Laplace transform and residue theorem are employed to derive the analytical solutions for the velocity and volumetric flow rate of the pulse electromagnetic flow. Graphical representations depict the effects of several important parameters, including the Hartmann number

H
a
,

pulse width

a
¯

,

relaxation time

λ
¯

1

and retardation time

λ
¯

2

on them. The study findings demonstrate that the Hartmann number

H
a

plays a vital role in the investigation of pulse electromagnetic flow. During the first half-cycle of the pulse electric field, the magnitude of the velocity amplitude increases and then decreases with the Hartmann number

H
a
.

An interesting observation is that in the second half-cycle, larger Hartmann number

H
a

values result in a decrease in velocity followed by a reverse increase. The profiles of velocity and volumetric flow rate exhibit oscillations over a relatively short period of time, then gradually reach a stable state with time and display periodic variation characteristics. Moreover, a larger pulse width

a
¯

leads to a longer variation period and more stable profiles of velocity and volumetric flow rate. For smaller Hartmann numbers

H
a
,

the magnitude of the volumetric flow rate amplitude grows with the relaxation time

λ
¯

1

and reduces with the retardation time

λ
¯

2

.

However, as the Hartmann number

H
a

increases, the influence of relaxation time

λ
¯

1

and retardation time

λ
¯

2

on the volumetric flow rate becomes significantly weakened, especially the retardation time

λ
¯

2

.
Graphene metamaterial-based broadband/dual-narrowband switchable terahertz absorber with adjustable absorptivity and large phase shift
Authors: Ma Xiaoya , Jiang Mingzhu , Song Zihang , Hu Fangrong , Zhang Longhui , Li Yanke , Han Jiaguang 
Published: September 2023

Abstract
We present a graphene metamaterial-based broadband/dual-narrowband switchable terahertz (THz) absorber with adjustable absorptivity and large phase shift. From top to bottom of the device, there are graphene-metal hybrid pattern, silicon dioxide layer, silicon layer and metal substrate. When the Fermi energy (EF) of graphene is equal to 0 eV, it has two narrowband absorption peaks at frequencies of 1.88 THz and 2.54 THz, respectively. However, when the EF is equal to 0.8 eV, it turns to a broadband absorber in the frequency range from 1.60 to 2.42 THz. Moreover, if the EF increases from 0.2 eV to 0.8 eV, its absorptivity can be dynamically adjusted from 60% to more than 90% in a broadband of 0.82 THz. Most importantly, the absorber can also dynamically control the phase shift. In the frequency range of 2.04 THz to 2.34 THz, a maximum dynamic phase shift of 192 degrees is achieved by changing the EF of graphene. This work provides an alternative method for constructing multifunctional integrated THz devices based on graphene metamaterial.
Local discrimination of lattice states via complete graph
Authors: Liu Qian-Qian , Yang Ying-Hui , Chen Pei-Ying , Wang Xiao-Li 
Published: September 2023

Abstract
In this paper, we use graph theory to study the distinguishability of lattice states under local operations and classical communication (LOCC) in

C

p

2

⨂

C

p

2

. Firstly, we present that for the basis of lattice unitary matrices, there are (p
2 + 1)(p + 1) distinct maximal commuting sets in p
2-dimensional system. Secondly, for any set



of lattice states, we can obtain a graph G which consists of some k-complete subgraphs. Using the graph G, we show that the set



can be distinguished by one-way LOCC if

n
(
p
+
1
)
−

∑

k
=
1

p
+
1

s

k

(
k
−
1
)
<
(

p

2

+
1
)
(
p
+
1
)

, where n is the number of vertices of a graph G and s

k
is the number of k-complete subgraphs. Moreover, we also proved that this conclusion is necessary and sufficient in

C

2

2

⨂

C

2

2

. For

C

p

2

⨂

C

p

2

system, our result can cover the results in (2015, Phys. Rev. A
92, 042 320); (2020, Sci. China-Phys. Mech. Astron.
63, 280 312).
New method to revisit the gravitational lensing analysis of the Bullet Cluster using radio waves
Authors: Yoon Youngsub , Park Jong-Chul , Hwang Ho Seong 
Published: September 2023

Abstract
Gravitational lensing studies of the Bullet Cluster suggested convincingly in favor of the existence of dark matter.
However, it was performed without the knowledge of the original orientation of each galaxy before gravitational lensing.
A potential improvement to this issue lies in the measurement of the original orientation from the polarization direction of radio waves emitted from each galaxy.
In this context, Francfort et al. derived a formula that can utilize the information about the original orientation of each galaxy to obtain what is called shear.
However, we demonstrate that shear in their formula should be replaced by reduced shear when the change in sizes of images of galaxies is taken into account.
As the previous gravitational lensing analysis of the Bullet Cluster used reduced shear, we suggest applying our improved formula directly for the reanalysis once we obtain the polarization direction of radio waves.
In particular, we show that our new formula can yield a more accurate analysis than the previous one, if the polarization direction can be measured more precisely than 10°.
Moreover, the approach discussed in this work is generically applicable to the gravitational lensing analysis of clusters, not only limited to the Bullet Cluster.
Study on the Effect of Anti-galloping Device with Cubic Stiffness and Particle Damping
Authors: Zhao Bin , Cheng Yongfeng , Wang Jingchao , Liu Bin , Chen Yushu 
Published: September 2023

Abstract
The galloping of iced conductors is a common disaster of overhead conductors. Most traditional anti-galloping devices lack a nonlinear dynamic vibration absorber; hence, they have a limited anti-galloping effect. In this study, we designed, optimized, and tested an electric power fitting and an anti-galloping device with cubic stiffness and particle damping for ultra-high-voltage (UHV) transmission lines. We built a nonlinear dynamic model of the coupling galloping system comprising split conductors and anti-galloping devices. The harmonic balance method obtained the steady-state analytical solutions and corresponding averaged equations. The test spans in the laboratory were used to design the test program and equipment. We verified the accuracy of the nonlinear dynamic model and the harvesting effect of the anti-galloping device with cubic stiffness and particle damping. The theoretical and experimental results were highly consistent, and in the range of (0, 2] Hz, the anti-galloping device reduced the galloping amplitude. Therefore, cubic stiffness and particle damping can effectively improve the anti-galloping ability of UHV transmission lines, prolonging their service period.
Study on Heat Transfer Performance of Flat Plate Pulsating Heat Pipe with Graphene Oxide at Low Heating Power
Authors: Shi Yang , Su Lei 
Published: September 2023

Abstract
Graphene oxide (GO) has high thermal conductivity and strong hydrophilicity which can enhance the heat transfer performance of the fluid. Standby heat transfer is a long-time, low-heat power and small heat area heat transfer, caused in electronic equipment. In this paper, the heat transfer performance of flat plate pulsating heat pipe (FPPHP) under the different concentrations of GO as working fluid is studied to solve the standby heat transfer and analyze the enhancement and the retardation of the GO to FPPHP. The FPPHP is made of aluminum, 2 tubes, with the concentration of GO, is 0.1%, 0.3%, 0.5%, a heating power range of 1∼10 W, and a filling rate (FR) is 30%. The results of the experiment indicate that under the condition of the concentration of 30% of GO, the FPPHP startup at 4 W and run stably at 6 W. When the heating power is 10 W, the wall temperature of evaporation is 89.75 °C, the thermal resistance is 1.18 °C/W.
Advanced exergy analysis of a novel air source heat pump system coupled with the liquid receiver and gas-liquid separator
Authors: Zhu Chao , Ma Longxia , Wang Fenghao , Wang Zhihua , Li Yongpeng , Liu Zixuan , Shi Peng , Ding Tao 
Published: September 2023

Abstract
In previous studies, an air source heat pump system coupled with the liquid receiver and the gas-liquid separator was proposed, which improved the defrosting efficiency according to the improvement of the refrigerant mass flow during defrosting and shortened the defrosting time. In this paper, the exergy efficiencies and exergy loss (including endogenous and exogenous exergy loss) of the new system are studied. They are compared with the original air source heat pump system by constructing the advanced exergy study model of the system. Results show that the exergy efficiencies of the compressor, evaporator, and throttle valve of the new system are increased by 0.2%, 2.3%, and 5.9%, respectively. The endogenous exergy loss of the new system accounts for 65.16% of the total exergy loss of the system, and most of the exergy loss in the new system is caused by the components themselves.
Hydrazine monohydrate modifying Ti3C2Tx in alkaline electrolytes for high-performance capacitive properties
Authors: Yang Jiaxin , Cui Weibin 
Published: September 2023

Abstract
MXene has shown a bright future in the electrochemical field, benefiting from its excellent conductivity and surface hydrophilicity. However, the performance of MXene in the field of supercapacitors is seriously impaired by restacking and a large number of F-containing functional groups, especially in alkaline electrolytes. Herein, hydrazine monohydrate is used to intercalate Ti3C2Tx, and the surface chemistry of MXene is effectively optimized. In 2 M KOH, the specific capacitance of Ti3C2-HM after modification is 157 F/g, which is 35% higher than the original one.
Numerical Simulation of Heat Transfer Characteristics of Finned Tube Heat Exchanger at Different Flow Velocities
Authors: Mei Chao , Li Ying , Yao Wenzhuo , Chen Mengdong , Kang Wei , Deng Zhanfeng 
Published: September 2023

Abstract
A heat exchanger is an important component where high-temperature hot air and normal-temperature water exchange heat. The heat exchange area of the finned tube heat exchanger is calculated by the rated working conditions. However, with the decrease of the heat storage temperature, the hot air temperature at the outlet of the thermodynamic energy storage device changes in a large range, directly affecting the heat exchange capacity and efficiency of the finned tube heat exchanger. This paper’s three-dimensional model is established. The heat exchanger of the finned tube is designed according to the temperature of the outlet section and the return section temperature of the heat storage system. The thermodynamic physical parameter property and characteristics of which heat exchanger’s finned tube in the air’s velocity range of 1∼10 m/s are simulated by fluent software. The velocity, temperature, pressure, and heat exchanger coefficient distribution characteristics at different positions along the airflow direction are obtained. The simulation results show that the mean flow velocity is 2.0 m/s and 5.0 m/s at the inlet cross-section. The average temperature difference between the inlet and outlet is 69.5 K and 100.5 K, respectively. The fin surface temperature difference between the first and eighth rows of finned tubes is 12.5 K and 14.4 K, respectively. The air pressure loss at the air channel inlet’s section and outlet’s section is 16.1 Pa and 69.4 Pa, respectively. When the inlet flow rate change from starting at 1.0 m/s and ending at 10.0 m/s, the tube’s wall coefficient of heat transfer, which is the second level of finned tubes, only increases by 1.8 times. The tube’s wall coefficient of heat transfer of the eighth level of finned tubes increases by the maximum, to 5 times the original, but the heat energy exchange capacity of which the second level of finned tubes is always the strongest.
Investigation of Heat Storage Coupled with Night Ventilation for Office Buildings in Summer in Cold Regions of China
Authors: Yin Chengtai , Xiu Pengyue , Ding Shuaijie , Zhang Guanmin 
Published: September 2023

Abstract
Building operational energy consumption, which constitutes a significant portion of China’s total social energy consumption, is a top priority in current research on energy-saving buildings. Thermal mass can be utilized to store heat energy in buildings, resulting in energy flexibility on the demand side. Numerical simulations in this paper study the whole heat transfer process of building thermal mass and the distribution of indoor air temperature and thermal mass temperature under different ventilation conditions in Jinan, a typical city in cold regions of China. By implementing a night ventilation scheme, buildings with high thermal storage capacity can store substantial amounts of cooling energy, resulting in a lower indoor temperature on the following day, and thereby improving overall indoor comfort. During the day, the wall surface temperature drops to less than 302 K, and the indoor temperature decreases by 2∼4 K, while the wall absorbs 1535 kJ of indoor heat. The rule of heat storage and release of heat mass is studied in this paper, and the feasibility of energy use flexibility on the demand side is demonstrated.
Evaluation of Renewable Energy Hosting Capacity of Grid with Multi-Infeed HVDC
Authors: Jiang Shiyao , Yu Haifeng , Xie Jiarui , Qi Junfeng , Tang Fei 
Published: September 2023

Abstract
Considering the impact of large-scale renewable energy access to a multi-infeed HVDC receiving-end system on its voltage stability and multi-infeed short circuit ratio, a renewable energy acceptance evaluation method based on an improved holomorphic embedding method is proposed. Firstly, to construct a model containing only an AC system, the DC inverter is simplified into an AC source model; secondly, the sigma index is used to judge the static voltage stability of the system bus and determine the access location of renewable energy, and sensitivity index is used to determine the scheme of replacing conventional units with renewable energy; then, with the voltage crossing the set range as the constraint condition, the analytical expression of each bus voltage obtained by the holomorphic embedding method is used to solve the maximum renewable energy capacity of the system; finally, under the maximum hosting scenario of renewable energy, verify the multi-infeed short circuit ratio at each DC drop point. The effectiveness of the proposed method is verified on an improved IEEE39-bus system.
Analysis of Migration Characteristics of Supercritical CO2 and Mechanism of Oil and Gas Production in Condensate Gas Reservoirs
Authors: Sun Boyu , Zhang Guofang , Wang Fuping , Hu Xu , Wang Xiulian 
Published: September 2023

Abstract
At present, circulating gas injection is the most effective development method for condensate gas reservoirs in China, but the phenomenon of dry gas overlap has seriously affected the development effect of circulating gas injection in condensate gas reservoirs, while CO2 injection is used to drive gas, which can make CO2 widely used in removing retrograde condensation of condensate gas reservoirs, improving the development effect of gas reservoirs. This paper by comparing the migration laws of injected dry gas and injected CO2 obtains that the dry gas with a smaller density flows to the upper space of the reservoir, while the CO2 with a larger density settles to the lower part. With the injection of CO2 into the reservoir, the content of CO2 in the crude oil increases, the volume of condensate oil expands significantly, and the flow capacity of condensate oil in the formation is improved. Injecting CO2 into the formation can reduce the viscosity of condensate. The mixture of CO2 injected into the formation and formation water is slightly acidic, which can dissolve some cement in the rock. With the increase of CO2 injection, the interfacial tension between oil and water will also increase, which is unfavorable for the stability of the oil-water system and is easy to emulsify. After demulsification, the viscosity will decrease and the condensate oil will flow more easily. The dissolved carbon dioxide in the water is in a weak acid state, which is easy to corrode and shed particles, improving the reservoir space and seepage conditions near the well. It will provide theoretical support for the effective development of a condensate gas reservoir.
Fabrication of flexible nitrogen and phosphorus-codoped porous carbon membrane and investigation of capacitance performance
Authors: Li Xiao , Zhou Bin , Qin Biao , Lan Yujin , Li Yihong , Zhao Shiyong , Cai Jiangtao 
Published: September 2023

Abstract
Porous carbon materials have been used extensively in new energy storage materials. They have the advantages of high stability, large specific surface area, and good electrical conductivity. However, carbon material capacitance still needs to be increased. In this paper, nitrogen and phosphorus-codoped porous carbon membrane (NPCM) was prepared by electrostatic spinning using polyacrylonitrile (PAN) as a carbon and nitrogen source, triphenylphosphine (TPP) as a phosphorus source and SBA-15 as a templating agent. When PAN/TPP was set to 2:1, the resulting NPCM has good flexibility, with N and P doping content of 13.8% and 0.5%, respectively, and a specific surface area of 872 m2/g. The NPCM was used as the working electrode with 1.0 M H2SO4 electrolyte and a specific capacitance of 215 F/g was achieved at a current density of 0.5 A/g by a three-electrode test, The capacitance retention rate could reach 103% after 1000 charge/discharge cycles at a current density of 2.0 A/g. Therefore, these results indicate that NPCM has great potential for application in high-performance flexible supercapacitors.