bluuebunny/crossref_metadata_2025_split huggingface dataset:
The scanning tunneling microscopy and spectroscopy of GaSb1–

x
Bi
x
films of a few-nanometer thickness grown by molecular beam epitaxy
Authors: Zha Fangxing , Zhang Qiuying , Dai Haoguang , Zhang Xiaolei , Yue Li , Wang Shumin , Shao Jun 
Published: September 2021

Abstract
The ultrahigh vacuum scanning tunneling microscope (STM) was used to characterize the GaSb1–

x
Bi
x
films of a few nanometers thickness grown by the molecular beam epitaxy (MBE) on the GaSb buffer layer of 100 nm with the GaSb (100) substrates. The thickness of the GaSb1–

x
Bi
x
layers of the samples are 5 and 10 nm, respectively. For comparison, the GaSb buffer was also characterized and its STM image displays terraces whose surfaces are basically atomically flat and their roughness is generally less than 1 monolayer (ML). The surface of 5 nm GaSb1–

x
Bi
x
film reserves the same terraced morphology as the buffer layer. In contrast, the morphology of the 10 nm GaSb1–

x
Bi
x
film changes to the mound-like island structures with a height of a few MLs. The result implies the growth mode transition from the two-dimensional mode as displayed by the 5 nm film to the Stranski–Krastinov mode as displayed by the 10 nm film. The statistical analysis with the scanning tunneling spectroscopy (STS) measurements indicates that both the incorporation and the inhomogeneity of Bi atoms increase with the thickness of the GaSb1–

x
Bi
x
layer.
The realization of a wide-angle voice transmission non-line-of-sight ultraviolet communication system
Authors: Deng Yangyang , Wang Yuehui , Zhang Yiqing , Du Axin , Liu Jianguo 
Published: September 2021

Abstract
A 300 kbps wide-angle non-line-of-sight ultraviolet communication system with voice transmission function is designed here. Based on Poisson distribution theory, we design the symbol detecting method for the receiving discrete photon signals. Using 272 nm LED array as the light source and PMT as the detector, the voice transceiver is integrated into the carriable size of 200 × 90 × 65 mm3. An outfield test shows the system obtains the BER of 0.88% under 200 m. Under 10° wide-angle deviation of the transmitter, a BER below 1.33% is achieved.
Effect of the post-gate annealing on the gate reliability of AlGaN/GaN HEMTs
Authors: Chen Changxi , Wang Quan , Li Wei , Wang Qian , Feng Chun , Jiang Lijuan , Xiao Hongling , Wang Xiaoliang 
Published: September 2021

Abstract
In this paper, we investigated the effect of post-gate annealing (PGA) on reverse gate leakage and the reverse bias reliability of Al0.23Ga0.77N/GaN high electron mobility transistors (HEMTs). We found that the Poole–Frenkel (PF) emission is dominant in the reverse gate leakage current at the low reverse bias region (V
th < V
G < 0 V) for the unannealed and annealed HEMTs. The emission barrier height of HEMT is increased from 0.139 to 0.256 eV after the PGA process, which results in a reduction of the reverse leakage current by more than one order. Besides, the reverse step stress was conducted to study the gate reliability of both HEMTs. After the stress, the unannealed HEMT shows a higher reverse leakage current due to the permanent damage of the Schottky gate. In contrast, the annealed HEMT shows a little change in reverse leakage current. This indicates that the PGA can reduce the reverse gate leakage and improve the gate reliability.
Coupled-ridge waveguide quantum cascade laser array lasing at λ ~ 5 µm
Authors: Yang Pengchang , Zhang Jinchuan , Gu Zenghui , Liu Chuanwei , Zhao Yue , Cheng Fengmin , Zhai Shenqiang , Zhuo Ning , Liu Junqi , Wang Lijun , Liu Shuman , Liu Fengqi 
Published: September 2021

Abstract
In this work, we demonstrated high-power quantum cascade laser (QCL) arrays lasing at λ ~ 5 µm by employing an optimized coupled-ridge waveguide (CRW) structure. Five-element QCL arrays were simulated and fabricated through a two-step etching method to extend the CRW structure to a mid-wave infrared regime. A lateral far-field with the main peak near a diffraction-limited intensity curve of about 10° was observed by properly designing a geometric shape of the ridges and interspaces. By introducing a buried 2nd-order distributed feedback (DFB) grating, substrate emission with a radiation power above 1 W at 25 °C is achieved. Single longitudinal mode operation is obtained by changing the temperature of the heatsink with a good linear wavelength tuning coefficient of –0.2 cm–1/K.
Pore-network distribution laws of cementitious materials detected by high-energy X-ray computed tomography imaging system
Authors: Lyu Qifeng , Guo Yanwei , Chen Anguo , Jia Jie 
Published: September 2021

Abstract
Pore networks of cementitious materials determine the materials’ properties and engineering safety. In this work, four kinds of cementitious materials which are geopolymer cement, foamed cement, ordinary concrete and pervious concrete were prepared, and a high-energy X-ray computed tomography imaging system was used to detect the samples’ inner structures. It was found that the pore network of such materials show similarity to social networks. However, the traditional mathematical degree which is the coordination number of a network is insufficient to characterize the pore networks, because such networks have volume limitations. Thus a new parameter, physical degree, was proposed in this work. By analyses of the pore networks of the samples, it was found the mathematical degrees follow Poisson distribution law whereas the physical degree can be fitted by power law. This indicates the pore networks are random and scale free. These findings may provide insight for future intelligent design of digital cementitious materials.
Finite Element Analysis on Hysteretic Behavior of H-shaped Columns of Thin-Walled Sections of 690 MPa High Strength Steel
Authors: Chen Zhongqi , Feng Wei , Guo Ruipeng , Liu Chunfeng 
Published: September 2021

Abstract
High strength steel is widely used in engineering, especially in light steel structures. However, due to the material properties of high strength steel, its seismic performance has attracted wide attention. To study the hysteretic behavior of H-shaped members of thin-walled sections of Q690 high strength steel, a finite element model was built up by using the general finite element analysis software ABAQUS. Based on the finite element model, an extensive parametric analysis of H-shaped members of thin-walled sections of Q690 high strength steel was carried out. The results showed that the limiting flange width-thickness ratio and web height-thickness ratio for H-shaped members of Q690 high strength steel were recommended to be 11 and 65, respectively, in actual engineering. Also, an increase in web height-thickness ratio and axial compression ratio could lead to a significant decrease in the ductility of H-shaped members of thin-walled sections of Q690 high strength steel. The thinner and more flexible the section is, the larger the axial compression ratio is, further reducing the energy dissipation ability of the members.
Mechanism experimental study on flooding control of Soft Microgel by low-field nuclear magnetic resonance
Authors: Ye Yinzhu , Wu Xingcai , Huang Zhuowei , Bi Taifei , Yang Zhe , Wang Xiaocong , He Lipeng , Liu Yang , Li Shichao 
Published: September 2021

Abstract
The research method of LF-NMR(low field nuclear magnetic resonance) combined with core displacement device has become important experiment was used to study the Water Flooding SCT(swept control technology by water flooding) of soft microgel. Besides, the transverse relaxation time spectrum and the “visual” evaluation method based on LF-NMR were used to investigate the microscopic mechanism of expended sweep volume of soft microgel in single core experiment. The displacement conformance effect of flexible microgel in parallel double-core and its displacement mechanism at different pore scales were analyzed by transverse relaxation time spectrum. The results of single core experiments show that the soft microgel can expand the sweep volume, mainly in the relatively large pore throat, with 15.43%. The results of parallel double-core experiments indicate that after SMG flooding, the recovery of low permeability core increased by 29.5%, high permeability core increased by 15.3%, comprehensive recovery increased by 22.0%, and the ratio of low permeability recovery increased by nearly 2 times that of high permeability core. The soft microgel flooding technology can effectively activate the remaining oil in different pore sizes of the core, among which the medium pore (12.1%) is more used than the large pore (5.6%) and the small pore (4.2%).
EMG-based Monitoring Muscle Contraction Force to Determine Most Effective Exercise
Authors: Fu Jiawei , He Yichen , Jiang Siming , Tao Zhongqi , Wen Yifan , Yi Xingyu 
Published: September 2021

Abstract
—Electromyography (EMG) signals have been widely applied in fields of biomedical, clinical and human-machine interface [1]. And surface EMG (sEMG) technology could provide a non-invasive way to detect the stimulation degree of muscles and enable the control of artificial limbs. In this research, the main focus lies on one of the social problems—sedentariness. With the development of internet and electronic economy, computing time has undergone a steady increase around the globe, which extends the job time in long-term sitting [2]. Together with some non-ergonomic designs of chairs, many officers might experience an abnormal sitting posture and get injured in their muscles unconsciously. To scope the phenomenon in detail, a simulation is applied to reappear the condition of sedentariness of a common office worker. And a series of easily achieved movements were investigated to find out the corresponding effect in muscle exercise to compensate the negative influence caused by long-term sitting.
Comparison of calculating methods and applications of different concrete maturity
Authors: Geng Da-jiang , Dai Ning , Jin Xue-sheng , Miao En-xin 
Published: September 2021

Abstract
Concrete maturity theory has great potential in practical engineering. In this paper, the calculation and application of the concrete maturity are presented based on the qualitative analysis and quantitative calculations. Firstly, the maturity calculations are summarized by the methods of direct calculation and equivalent age calculation, as well as a theoretical discussion of the advantages and disadvantages of each calculation method. Secondly, the main methods of compressive strength and elastic modulus predicted by the concrete maturity are also summarized, and the calculation accuracy of the main calculation methods is compared with the published test results. Finally, based on actual engineering project, the research on concrete maturity is prospected to clarify the further research direction. The results show that the calculation methods of concrete maturity consist of direct calculation method and equivalent age calculation method, and the equivalent age calculation method is more reasonable in theory. Considering the wide range of construction temperature, the Freiesleben-Hansen equivalent age equation and exponential function prediction equation are recommended to predict the strength and elastic modulus of concrete.
Method for generating mesostructure of soil-rock mixture based on Minkowski sum
Authors: Zhang Peng , Chen Junqi , Xian Qingjun 
Published: September 2021

Abstract
The soil-rock mixture is widely distributed in nature, and the mechanical properties of it is a key concern in geotechnical engineering field. The mechanical response of soil-rock mixture can be obtained using numerical approaches. As the precondition for numeric simulation, the mesostructure of soil-rock mixture is indispensable. The random rock packing is the main step in the construction of the mesostructure. The classical trial packing method are inefficient when the rock area fraction is high. Permissible positions to pack new rock can be predicted in the algorithm using entrance block and background mesh, resulting in dramatic improvement in efficiency and robustness. Entrance block and Minkowski sum can be transformed into each other, and there are more algorithms for Minkowski sum. Therefore, a random rock packing algorithm based on Minkowski sum is constructed, each rock can be packed successfully at one time, avoiding multiple trials in the traditional trial packing method and improving the efficiency of packing.
Study on constraint degree calculation of frozen shaft inner wall mass concrete
Authors: Fang-zheng Li , Ji-wei Zhang , Wei-dong Wu , jin Yao , Xiao-gang Jin 
Published: September 2021

Abstract
Based on the circle-shaped air shaft of Hong Qing-He coal mine located in Inner Mongolia China, the thermal-mechanical numerical model of frozen shaft inner wall mass concrete was established under complex thermal-mechanical boundary, including internal heating, external cold source, friction constraints, above shaft load and lateral pressure. The evolution characteristics of temperature-displacement field of inner wall were analysed. According to numerical simulation results, the constraint degree at the middle section of inner wall concrete is calculated. In the early stage (0-10d), the constraint degree of inner wall fluctuates within 60-99% as curing time goes. Three protection measures to delete confinement degree of mass concrete shaft wall were proposed, including (1) Reducing the friction between inner and outer walls; (2) Reducing hydration heat release of mass concrete; (3) Reducing the temperature difference between inner and outer walls during curing.
Treatment technology for large deformation of tunnel passing through soft and fragmented zone
Authors: Xiaoteng Liang , Zhangru Shi 
Published: September 2021

Abstract
Large deformation is a major problem for tunnels, threatening engineering safety and increasing construction costs. In order to solve the large deformation problem of deep-buried tunnels passing through the soft and fragmented zone, relying on the Dafalang tunnel project under construction, the mechanism of the large deformation of the fracture zone tunnel is analyzed, and deformation control measures suitable for geological conditions are proposed accordingly. The large deformation of the Dafalang tunnel is the combined effect of many factors. The complex tectonic stress environment is the mechanical condition for the large deformation of the tunnel. The weak and broken surrounding rock is the material basis and internal condition of the large deformation of the tunnel. Optimizing construction parameters, grading deformation control, and combined length and short anchor rods are adopted to effectively reduce tunnel deformation and ensure construction safety and progress.
Preparation of CuO/Ag rough nanostructures as SERS-active substrates
Authors: Yang Qiong , Wang Jingjing , Wu Haoran , Li Chaorong 
Published: September 2021

Abstract
In this paper, CuO nanostructures with nanometer roughness were firstly prepared by electrochemical anodic oxidation method, and then CuO/Ag composite nanostructures were prepared by magnetron sputtering method on the surface of CuO substrate. The successful deposition of Ag films on CuO was confirmed by XRD, UV-Vis and SEM. In addition, the effects of different Ag sputtering time on substrate morphology and SERS properties were studied. Due to the many gaps between the rough CuO/Ag nanomorphology, the substrate has many “hot spots” and adsorption sites, which can effectively improve the SERS performance of the substrate. We selected R6G dye molecule as the probe molecule to evaluate the SERS performance of the substrate. The final experimental results show that the preparation method of CuO/Ag rough nanostructure is simple, and it has significant SERS performance improvement. The substrate’s detection limit for R6G can even reach 10-11M.
Compressive properties and microstructure evolution of sintered nano-silver
Authors: Gong He , Wu Hongcheng , Guo Hongcun , Yao Yao 
Published: September 2021

Abstract
In this work, the compressive properties of sintered nano-silver applied to the third generation semiconductor at room temperature are tested at a loading rate of 10-2s-1. The compressive stress-strain curve shows obvious elastic and plastic stage, and with the failure of the pore wall and sintering neck, the damage accumulates gradually until failure. The microstructure is analyzed statistically by scanning electron microscope. A finite element model for porous structure is developed by matching scanning electron microscope analysis. The elastic modulus of pore wall and sintering neck is obtained by combining the macro experimental data with the Ashby model. The local failure process of sintered nano-silver is simulated numerically. It is noted that the failure path is determined by large pore and pore spacing.
Mechanisms of Sinomenine Nanoparticles in the Treatment of Breast Cancer Based on Network Pharmacology
Authors: Chen Ting , Huang Xulong , Yang Chao , Huang Bin 
Published: September 2021

Abstract
This article mainly discusses the mechanism of SINOMENINE nanoparticles in the treatment of breast cancer by using the network pharmacology method. TCMSP and Swiss Target Prediction databases were searched for the target of SINOMENINE. The “breast cancer” target was searched through the GeneCards database. The common targets of both SINOMENINE and breast cancer were considered as the targets of SINOMENINE for treating breast cancer. The software Cytoscape 3.7.1 was used for topological analysis and visualization. The DAVID databases were used for GO enrichment analysis. A total of 57 key targets for the treatment of breast cancer were obtained, of which AKT1, MTOR, EGFR, NOS3, MAPK8, MMP9, etc. The results of pathway enrichment and functional annotation show that SINOMENINE mainly involves protein phosphorylation and positive regulation of nitric oxidebiosynthetic process by regulating Sphingolipid signaling pathway, Pathways in cancer, Measles, Smallcell lung cancer, Focal adhesion, and Insulin resistance. There are 10 major biological processes, including protein phosphorylation, signal transduction, negative regulation of apoptotic process, and protein autophosphorylation. This study not only initially revealed potential molecular mechanism of SINOMENINE, but also provided a reference for the in-depth development of SINOMENINE nanoparticles for the treatment of breast cancer.
Study on Permanent Thermal Insulation Formwork of Mass Concrete Prepared by Different Types of Nano-modified Lightweight Aggregate
Authors: Jiang Xiaojian , Zhang Sijia , Gu Zhifeng , Wang Licheng , Zhao Yunfei 
Published: September 2021

Abstract
Aiming at the problems of low strength, flammability, easy falling off, and aging of traditional organic thermal insulation materials, inorganic thermal insulation materials of different types of nano-modified lightweight aggregates were prepared in this paper. The feasibility of preparing permanent thermal insulation formwork of mass concrete with nano-modified lightweight aggregate was studied through experiments and calculation analysis of mechanical, durability, and thermal properties. The results show that the water absorption of shale ceramsite modified by nano-permeable hydrophobic agent is reduced to 1.21%, and the water absorption rate of inorganic precast hollow aggregate produced by nano-silica powder is lower, which is 0.79%. Inorganic precast hollow aggregate concrete, modified shale ceramsite concrete, and organic foamed aggregate concrete have the characteristics of high strength, fire resistance, aging resistance and low thermal conductivity. Inorganic precast hollow aggregate concrete and modified shale ceramsite concrete have excellent impermeability and frost resistance. Organic foamed aggregate concrete has the lowest thermal conductivity and good thermal insulation effect and its durability can be improved by surface protection technology. According to the principle of equivalent surface heat release coefficient, it is feasible to use lightweight aggregate precast formwork as permanent insulation formwork of mass concrete with thickness between 50 and 100 cm. The permanent thermal insulation formwork of nano-modified lightweight aggregate concrete can also be used as the formwork for concrete construction to realize the temperature control measures of tracking thermal insulation and slow cooling of mass concrete, reduce the risk of cracking, and improve the construction efficiency.
Study on ionic liquid treatment and enzymatic hydrolysis of corn stover after activation of zinc chloride solution
Authors: Zeng Guoming , Huang Xin , Li Yan , Sun Da , Zhou Bin 
Published: September 2021

Abstract
With the intensification of the energy crisis, this thesis uses corn stalk cellulose as the raw material to carry out research on biomass energy. By designing the response surface experiment, a multiple quadratic regression equation prediction model of the response surface factors and the yield of enzymatic reducing sugars after the activation of the zinc chloride solution treated by the ionic liquid was established, which provided the technology for the ionic liquid treatment of the metal ion solution to activate the corn stalk raw materia reference. The experimental results show that the yield of enzymatically hydrolyzed reducing sugars of corn stalks after being activated by metal ions and then treated with ionic liquids is greatly improved compared to the raw materials.
Study on Micro-arc Oxidation of Mg-Zn-Y-Nd-Ca Magnesium Alloys
Authors: Dai Yuelai , Li Yulei , Lv Juan , Li Jingwei 
Published: September 2021

Abstract
To solve the problem of rapid degradation of magnesium alloy implanted in human body, the surface of magnesium alloy was modified by micro-arc oxidation treatment. In order to improve the comprehensive mechanical properties and corrosion resistance of magnesium alloy materials, a new type of Mg-Zn-Y-Nd-Ca degradable magnesium alloy materials was formed by adding a certain proportion of rare earth elements Y and Nd, as well as Zn and Ca. A micro - arc oxidation layer containing Ca, P and Si was formed on the surface of magnesium alloy by secondary micro - arc oxidation. The surface of the micro-arc oxidation film was covered by sol-gel technology to reduce the micro-crack and micro-pore structure of the film and improve the corrosion resistance of the film in the human body simulation liquid.
Metal-Organic-Frameworks-driven hollow core-shell C03O4/TiO2 Heterojunction for Enhancement of Photocatalytic Hydrogen generation
Authors: Xiao Guangsheng , Pan Jiaqi , Fu Yueyue , Li Chaorong 
Published: September 2021

Abstract
In recent years, how to further enhance the efficiency of photocatalytic hydrogen generation has become a research hotspot. At present, the metal-organic-frameworks (MOF) has attracted much attention in the field of catalysis due to its special physical and chemical properties. Herein, the hollow core-shell Co3O4/TiO2 heterojunction is prepared by deposition and annealing method with ZIF-67 as self-sacrificial templates and metal precurous. The characterzation of XRD, SEM, and TEM indicate that the hollow core-shell Co3O4/TiO2 heterojunction is synthesized successfully. The characterzation of UV, PL indicate that the Co3O4/TiO2 show superior photoelectric performance. By evaluation, the Co3O4/TiO2 heterogeneous catalyst exhibits a remarkable photocatalytic hydrogen production performance, which is ∼11 and ∼14 times higher than that of pure Co3O4 and TiO2. Studies prove that the formation of heterojunction can promote charge carriers separation, the hollow structure can raise the solar efficiency, offer more surface areas and active sites, all these are beneficial for photocatalytic performance.