bluuebunny/crossref_metadata_2025 huggingface dataset:
A metabolic regulon reveals early and late acting enzymes in neuroactive Lycopodium alkaloid biosynthesis
Authors: Nett Ryan S. , Dho Yaereen , Low Yun-Yee , Sattely Elizabeth S.
Published: June 2021

Significance

Plants have evolved to produce an abundance of neuroactive small molecules. Many major classes of these compounds are derived from the amino acid lysine, including the Lycopodium alkaloids, which are produced by club moss species that are traditional herbal medicines in several cultures. In this work, we describe a likely metabolic regulon, or transcriptionally coregulated group of metabolic genes, for the Lycopodium alkaloids in the club moss
Phlegmariurus tetrastichus
, which we used to identify six enzymes within the biosynthesis of huperzine A (HupA), an acetylcholinesterase inhibitor with clinical interest as a treatment for neurological disease. Our results demonstrate precise transcriptional coregulation of biosynthetic steps within Lycopodium alkaloid metabolism and further uncover diverse enzymatic transformations for lysine-derived alkaloid biosynthesis in plants.
Thermodynamics of dynamical wormholes
Authors: Rehman Mudassar , Saifullah Khalid
Published: June 2021

We study thermodynamics of dynamical traversable wormholes.
The surface gravity is evaluated on the trapping horizon and the
unified first law of thermodynamics is set up. The thermodynamic
stability of these wormholes has been investigated. We have also
extended these results to charged dynamical wormholes. Our results
generalize those that exist for static Morris-Thorne wormholes.
A review of manufacturing technologies for silicon carbide superjunction devices
Authors: Tian Run , Ma Chao , Wu Jingmin , Guo Zhiyu , Yang Xiang , Fan Zhongchao
Published: June 2021

Superjunction technology is believed to reach the optimal specific on-resistance and breakdown voltage trade-off. It has become a mainstream technology in silicon high-voltage metal oxide semiconductor field effect transistor devices. Numerous efforts have been conducted to employ the same concept in silicon carbide devices. These works are summarized here.
Modeling the photon counting and photoelectron counting characteristics of quanta image sensors
Authors: Liu Bowen , Xu Jiangtao
Published: June 2021

A signal chain model of single-bit and multi-bit quanta image sensors (QISs) is established. Based on the proposed model, the photoresponse characteristics and signal error rates of QISs are investigated, and the effects of bit depth, quantum efficiency, dark current, and read noise on them are analyzed. When the signal error rates towards photons and photoelectrons counting are lower than 0.01, the high accuracy photon and photoelectron counting exposure ranges are determined. Furthermore, an optimization method of integration time to ensure that the QIS works in these high accuracy exposure ranges is presented. The trade-offs between pixel area, the mean value of incident photons, and integration time under different illuminance level are analyzed. For the 3-bit QIS with 0.16 e-/s dark current and 0.21 e- r.m.s. read noise, when the illuminance level and pixel area are 1 lux and 1.21 μm2, or 10 000 lux and 0.21 μm2, the recommended integration time is 8.8 to 30 ms, or 10 to 21.3 μs, respectively. The proposed method can guide the design and operation of single-bit and multi-bit QISs.
Determination of trap density-of-states distribution of nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite films
Authors: Shaban Mahmoud
Published: June 2021

Thin films comprising nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous-carbon (UNCD/a-C:H) composite films were experimentally investigated. The prepared films were grown on Si substrates by the coaxial arc plasma deposition method. They were characterized by temperature-dependent capacitance-frequency measurements in the temperature and frequency ranges of 300–400 K and 50 kHz–2 MHz, respectively. The energy distribution of trap density of states in the films was extracted using a simple technique utilizing the measured capacitance-frequency characteristics. In the measured temperature range, the energy-distributed traps exhibited Gaussian-distributed states with peak values lie in the range: 2.84 × 1016–2.73 × 1017 eV–1cm–3 and centered at energies of 120–233 meV below the conduction band. These states are generated due to a large amount of sp2-C and π-bond states, localized in GBs of the UNCD/a-C:H film. The attained defect parameters are accommodating to understand basic electrical properties of UNCD/a-C:H composite and can be adopted to suppress defects in the UNCD-based materials.
Oscillation neuron based on a low-variability threshold switching device for high-performance neuromorphic computing
Authors: Li Yujia , Tang Jianshi , Gao Bin , Li Xinyi , Xi Yue , Zhang Wanrong , Qian He , Wu Huaqiang
Published: June 2021

Low-power and low-variability artificial neuronal devices are highly desired for high-performance neuromorphic computing. In this paper, an oscillation neuron based on a low-variability Ag nanodots (NDs) threshold switching (TS) device with low operation voltage, large on/off ratio and high uniformity is presented. Measurement results indicate that this neuron demonstrates self-oscillation behavior under applied voltages as low as 1 V. The oscillation frequency increases with the applied voltage pulse amplitude and decreases with the load resistance. It can then be used to evaluate the resistive random-access memory (RRAM) synaptic weights accurately when the oscillation neuron is connected to the output of the RRAM crossbar array for neuromorphic computing. Meanwhile, simulation results show that a large RRAM crossbar array (> 128 × 128) can be supported by our oscillation neuron owing to the high on/off ratio (> 108) of Ag NDs TS device. Moreover, the high uniformity of the Ag NDs TS device helps improve the distribution of the output frequency and suppress the degradation of neural network recognition accuracy (< 1%). Therefore, the developed oscillation neuron based on the Ag NDs TS device shows great potential for future neuromorphic computing applications.
The Relationship Between the Chinese Stock Market, the US Stock Market, and Some Other Economic Indexes Under the COVID-19 Pandemic
Authors: Yang Jinyu , Jia Ziyi , Mao Yunxiang
Published: June 2021

The COVID-19 outbreak has had a huge impact on all sectors of the world, especially the economy. Among all the economic indicators, the stock market indexes are particularly important, because the stock markets anticipate the future economic change and reflect investor confidence and thus may be the barometer of the overall economy. The Chinese and US stock markets are the most important stock markets. Because New York Stock Exchange (NYSE) and National Association of Securities Dealers Automated Quotations (NASDAQ) have the greatest market cap worldwide. And Shanghai Stock Exchange (SSE) and Hong Kong Stock Exchange (HKSE) can obviously show the conditions of economy in the mainland of China and East Asia. We collected the daily increase or decrease indexes of the U.S. and China stock markets to study their relationships and how they are affected by the pandemic. To study this problem, this paper uses three methods, including Local Similarity Analysis (LSA), Least absolute shrinkage and selection operator (LASSO) and Markov chain. We calculate the correlation between the U.S. stock indexes and China stock indexes with LSA and analyze the possible factors which lead to these correlations. LASSO is used to find out other economic indexes which affect the U.S. and China stock markets and test whether these indexes can predict the trend of future markets. Lastly, Markov chains can be used to analyze the effects of the day to the next day transmission in stock markets. We find that there is a high correlation between the U.S. and the China stock using LSA, especially, from Jan.10 to Feb.10. We find that Shanghai Stock Exchange Composite Index (SSEC) and NASDAQ are correlated to the Standard and Poor’s 500 Index (S&P500) in the US market. S&P500, confirmed cases of COVID-2019 in China (Chinese cases), USD to CNY exchange rate are correlated to the SSEC in the Chinese market. Using these indexes, the future indexes of the U.S. stock market can be predicted at a PCC correlation, the highest is 0.44 and the lowest is 0.24 for the China market. LASSO shows that the U.S. market can be more accurately predicted by the indexes. The estimated Markov models of the two stock markets are pretty similar, i.e. the probability that the value of the U.S. stocks increases two days in a row is 13.40% and the Chinese market is 11.34%. To sum up, we find that the two stock markets are highly correlated under the Covid-19 pandemic despite from some differences.
Convergence of a higher order finite difference scheme for two-phase Stefan problems.
Authors: Martínez-Rosado R , Castillo-Aranguren F , Santiago-Acosta R D , Hernández-Cooper E M , Otero-Hernández J A
Published: June 2021

This work establishes a sufficient condition for convergence of a semi-implicit finite difference scheme with variable space grid of fourth order of accuracy in space, previously set by the authors. The scheme is intended to solve one-dimensional two-phase Stefan problems. The proofs of the above-mentioned results are based on estimates which are obtained and subsequently employed in order to find an upper bound of the discretization error both at phases and the interface. The computational behavior of the scheme under the sufficient condition is corroborated by a series of numerical tests.
Exact Solution for a Rectangle with Rigidly Clamped Horizontal Sides
Authors: Menshova I V , Kerzhaev A P , Shulyakovskaya T D , Yu G , Zeng X
Published: June 2021

In this paper, in the form of expansions in Papkovich–Fadle eigenfunctions, an exact solution to the boundary value problem of the theory of elasticity is constructed for a rectangle whose horizontal sides are rigidly clamped. The expansion coefficients are determined with the help of biorthogonal functions by simple formulas.
2-Dimensional Regional Mapping of Ionospheric Total Electron Content Using Kriging Interpolation over the Philippines: Initial Results
Authors: Maglambayan Vincent Louie L. , Mendoza Merlin M. , Macalalad Ernest P.
Published: June 2021

Total electron content (TEC) is an important parameter in studying the characteristics of the ionosphere of the Earth. By measuring the phase and group delays of the signals produced by Global Navigation Satellite System (GNSS) satellites, the slant TEC along the ray path can be measured. Assuming that the ionosphere is a thin shell, the point of intersection between the shell and the ray path is the ionospheric pierce point (IPP). The slant TEC at this point can be converted to the vertical TEC (VTEC). To produce continuous 2-dimensional TEC maps, a mapping method must be used based on the data that has been measured. While there are numerous methods to map TEC that are in used today, this study investigates the performance of Kriging interpolation over the Philippine region using the data from the Philippine Active Geodetic Network (PAGENet). To test the performance, the maps produced were compared to the Global Ionosphere Maps (GIMs) which are provided by the International GPS Service (IGS). The initial results show that the PAGENet maps have lower TEC values compared to GIMS with a mean difference of ~6 TECU with 12 UT having the highest difference.
The Correlation between Solar Wind and Active Sunspot AR2776 in 25th Solar Cycle
Authors: Hamidi Z S , Shariff N N M
Published: June 2021

The solar wind is one of the main properties of the Sun which has a stream of charged particles released from the corona of the Sun. The study of this parameter has started in 1957 and there are a few models that related to prove how the solar wind could escape from the Sun’s gravity. In this paper, we choose the latest solar event that occurred on 16th October 2020 in this new 25th solar cycle. During these months, the Sun considered as active mode and the active region AR2776 potentially contributes high solar activities. Uniquely, a micro solar flare class B formed together with solar burst type II. A very intense flashing which also known as Ellerman bombs can be detected in the optical region. The sunspot number is only 14 and solar wind exceeds up to 306 kms -1 with a density of 4.0 protons/cm 3. We confirmed that AR2776 is a member of Solar Cycle 25.
Theoretical Quantum Immortality and its Mathematical Authority
Authors: Han Ce
Published: June 2021

Quantum Immortality usually refers to, in a classical sense, a person who is “lucky” enough to survive in any incident in the world. Such a quantity of luckiness is even big enough to keep that person away from the aging of the human body. That is, in fact, when we say that one becomes “immortal”. Throughout the history of the world, there have been many times when people tried to find out the secret of anti-aging, but this ambitious dream, obviously, has failed every time. This paper will discuss quantum immortality in theoretical and mathematical aspects and evaluate its authority, or possibility, of its existence in real life. In order to accomplish this evaluation, the concepts of the main two interpretations of quantum physics: 1)Copenhagen Interpretation(or non-MWI interpretation), and 2)Many Worlds Interpretation(or MWI)will be necessarily involved. Throughout this paper, the MWI is proven to support the theoretical quantum immortal state, which, in this paper, means to achieve an expected theoretical outcome in the Everett box experiment. In order to show how MWI will give its credit to quantum immortality, the idea of the Infinite Monkey experiment is demonstrated in detail. After that, discussions of the computable probability of the outcome of the Infinite Monkey theorem and its pathological distribution are involved. Regardless of the situation in the Everett box, whether it is pathologically distributed or not, the mathematical outcomes show that MWI will be the only possibility of achieving the quantum immortal state during the Everett box experiment, or quantum gun experiment. Finally, the paper brings out the evaluation of quantum immortality in a real life stance.
Spatial tourism supply: the case of ASEAN-5 countries
Authors: Chaiboonsri C , Wannapan S , Chokethaworn K
Published: June 2021

This article is the applied econometric analyses in estimating the spatial stochastic frontier (SSF) model. The heart of the modelling inference is Bayesian statistics with Gibbs sampling, which can provide flexible parametric distributions for capturing abnormal distributional observations. Yearly panel data between 2008 and 2018 regarding tourism supplies such as numbers of hotels, service rooms, and labour forces in ASEAN-5 countries (Vietnam, Indonesia, Malaysian, Singapore, and Thailand) is observed. The empirical results are divided into two major parts. The first section is the understanding of spatial effects which causally relate to the way for expanding tourism supplies is explained by the model validation using deviance information criterion (DIC). The panel spatial-error stochastic frontier (random-effect model) contains the minimum DIC which implies the parameters of locational effects is the minor, but it should be still considered for stimulating tourism supply sides in these five countries. The second section is the estimation of random parameters are processed to monitor technical efficiencies. Spatial effects are a specific impact on the group of connected borderline countries. On the other hand, this impact is dependently reduced when a country contains a remote area condition. Ultimately, this paper is the alternative to better analyse supply-chain management in the tourism sector without the restrictions of P-value, asymptotic struggling, and multicollinear problems. For further researches, subjective statistics (Bayesian) is the main issue that applies for modern econometrics.
Using a new muscle activation model to improve the stability of force estimation with Hill-type models over different activation levels
Authors: Hussein Moemen , Shebl Said , Elnemr Rehab , Elkaranshawy Hesham
Published: June 2021

Hill-type models are attractive in biomechanics simulation due to their low computational cost and commonly measured parameters. They mainly consist of two parts, the activation dynamics, and the contraction dynamics. Since Hill-type models are phenomenological models, it is meant to capture the process’s main characteristics using a descriptive system that approximates the behaviour of the real physical one. This paper developed a novel activation dynamics formulation to estimate the force of the triceps surae muscles at two different contraction levels without retuning the model parameters. The new formulation simulates the cell calcium dynamics as well as the recently discovered role of store-operated calcium entry (SOCE) channels. The proposed model reflects the main characteristics required from the activation model, which are the electro-mechanical delay, the process nonlinearity, and the ability to couple the activation process with some parameters from the subsequent force-generating process. The parameters of the model are task-independent to closely approximate the muscle function and to have the ability to simulate different movements adequately. The model shows a more stable performance along with different contraction levels in comparison with two other activation models.
Monthly Observations of Cold-point Tropopause Temperature and Height for 2008 in the Philippines Using COSMIC GPS Radio Occultations
Authors: Eugenio Ryan G. , Macalalad Ernest P.
Published: June 2021

The cold-point tropopause (CPT) is the thermal boundary between the troposphere and stratosphere defined by a temperature profile’s coldest level. In this paper, the CPT is examined using temperature profiles from Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) GPS radio occultation measurements during 2008 inside the Tropical Cyclone Advisory Domain (TCAD) in the Philippines. The monthly and spatial variability is examined using two CPT properties: CPT temperature (CPT-T) and CPT height (CPT-H). Generally, the coldest CPT temperatures are in the months of December-January-February, which lie within the cool dry season. CPT-T is at its hottest in July-August-September, within the rainy season. CPT-H is observed to decrease (increase) as CPT-T increases (decreases), suggesting an inverse relationship between the two properties. CPT-T is also observed to rise in the upper latitudes, while no discernible spatial pattern can be seen for CPT-H over this domain expect for that the start increase and decrease of CPT-H appear to occur over the Pacific first.
The Comparison of Secure Key Rate of BB84 Protocol Using Single Photon Detectors and Optical Homodyne Detectors
Authors: Xiong Peiyao
Published: June 2021

To increase the security and efficiency of information transmission, the technology of Quantum Key Distribution is developed. A simulation of secure key rate of BB84 protocol is done to give a visualized comparison of efficiency of the protocol using different light sources and detectors. The simulation shows that the Poisson light source is less efficient than single photon source and the secure key rate of using continuous variable detectors is lower than using discrete variable detectors.
Code Transformation Impact on Compiler-based Optimization: A Case Study in the CMSSW
Authors: Ploensin Teerit , Piromsopa Krerk , Srimanobhas Norraphat
Published: June 2021

In this paper, we study the benefit of applying loop transformations to a part of module in the CMS software. Particularly, we focus at the effect of loop transformations in term of performance improvement from the optimization process of compilers. Loop optimizations have been considered at low-level phase, such as loop unrolling using compiler directive. For high-level code transformations such as index set splitting and loop reordering, we adopt the polyhedral model to simplify the transformations. In this study, our loop optimization has been evaluated quantitatively. We study the impact on loops execution speed up and its instruction executed. Our observation shows that high-level loop optimizations can reduce both execution time and the number of instruction. This behavior suggested that simple loop transformations can trigger other optimizations. Moreover, we not only improve the overall performance, but also reduce the number of instruction. The results show that loop optimizations yield the speed up between 1.5 and 1.7.
Retraction: Bayesian estimation of scale factor for CG-5 relative gravimeter (IOP Conf. Ser.: Earth Environ. Sci.
734 012037)
Authors: Zheng Qiuyue , Liu Dong , Wang Linhai , Huang Jiangpei , Wang Qinghua
Published: June 2021

This article has been retracted at the authors request, for the following reasons:

•The work was submitted without the approval of the one of the co-authors, Linhai Wang.

• The original gravity data used in the paper has been found incorrect through repeated verification recently, which is leading to erroneous conclusions.

•The theoretical method used needs further development before it is ready for publication.

All co-authors agree to this retraction.

Retraction published: 10 June 2021
Effects of alternating stray current on chloride transport in cement-based materials
Authors: Tang Mengxiong , Hu Hesong , Zhu Wen , Zhao Ruying , Zhang Yanli , Luo Kun , Wu Jiang , Zhang Shuo
Published: June 2021

A series of tests were conducted to investigate the effects of alternating stray current on chloride transport in cement-based materials (mortar). The chloride distributions in the mortar after the conditioning of immersion in 35 g/L NaCl solution or coupled with direct/alternating stray current within 14 days were gained. Test results show that: (1) The distribution of chloride ions along the depth in mortar shows an exponential shape, after the conditioning of immersion in 35 g/L NaCl solution or coupled with direct or alternating stray current within 14 days; (2) Comparing with the immersion in the NaCl solution without stray current, the transport of chloride in the mortar under DC electric field is significantly accelerated. The maximum chloride content in the mortar under this environment was almost seven times higher than that in the condition without current; (3) The chloride contents at different depths of the mortar in the AC electric field are slightly less than those in the solution without electric field and are much less than that with direct stray current.
The uses of FR and QWL for site effect
Authors: Tao Z , Liu S , Tao X , Cao Z
Published: June 2021

For an engineering site without strong motion records, the effect of full resonance (FR) and quarter-wavelength (QWL) to evaluate site response is discussed by comparing the predicted ground motion at each interface with the analytical solution of the frequency-wavenumber (F-K) method. We analyse the differences of time histories and amplitude spectra, with the inputs of full wave and upward wave on the buried bedrock. By comparing with the F-K result, the input of upward wave is reasonable. A solution to extract upward wave from full wave is presented and proved.
Ultimate capacity analysis of transmission tower line system under wind load
Authors: Zhu Yang , Zhang Xin , Xie Qiang
Published: June 2021

As an important part of the large complex lifeline system, the transmission tower line system has many accidents. Based on the static and dynamic calculation theory, the response of the structure is analyzed, the ultimate capacity of the transmission tower system is obtained, and the weak position is studied, and the ultimate capacity of the transmission line is comprehensively evaluated. The result shows that the weak position is Segment 4 and 5 of the transmission tower, and the ultimate capacity of dynamic analysis is smaller than that of static analysis.
A new snow removal device and determination of for membrane structures
Authors: Wang B S , Zhang Y K , Meng L , Li S , Zhang H , Song Q H
Published: June 2021

In order to avoid the damage of membrane structure caused by snow load, a new type of intelligent snow removal device is proposed based on the principle of micro-spray irrigation and the dual control of pressure and temperature. The determination method of construction parameters such as pressure critical value, snow area, sprinkler size and number of the device is expounded. Finally, taking a Shanghai membrane structure project as an example, the snow area of the project was determined. Considering the size of snow area and the sprinkler spraying area, the number and construction location of the sprinklers on the membrane surface were finally determined.
Applicability analysis of squeezed branch pile with different embedded depth of Boulder
Authors: Wen-tong ZHU , Hai-qin LI , Jun-yan ZENG , Wei-dong GUAN
Published: June 2021

Based on Zhongshan-Tan zhou express 65 # pier boulder geological engineering landscape avenue viaduct, using PLAXIS3D to study in the different boulder embedment depth of squeezed branch piles expansion and common pile ultimate bearing capacity and the applicability of the squeezed branch piles expansion, the calculation results show that the squeezed branch piles expansion of P - S curve is slowly, the ultimate bearing capacity of pile is equal to the load value corresponding to the pile tip diameter when the pile settlement is 1/20, and the ultimate bearing capacity of pile foundation does not always increase(the peak point appears) with the increase of pile length, but the ultimate bearing capacity of ordinary pile is less than the ultimate bearing capacity of extrudated and expanded bracing pile. Under certain geological conditions, the pile length can be shortened and the bearing capacity of pile can be improved effectively. On the basis of the load of the upper bridge which satisfies the geological condition of boulder, the use of extrudated and expanded bracing pile instead of ordinary pile can effectively avoid the boulder, avoid the pile passing through the boulder layer, which can greatly save the construction period and reduce the difficulty of construction.
Analysis of the influencing parameters of double steel-plate composite shear wall
Authors: Xu Z P , Gao X L
Published: June 2021

The double steel plate concrete composite shear walls are widely used in nuclear power structures due to good bearing capacity, deformation capacity and radiation resistance. The shear walls of nuclear power structures are totally different with that in the civil buildings, which have the characteristics of small shear span to depth ratio and large thickness. On the basis of summarizing and analysing the test results of double steel plate composite shear wall, finite element models were established to verify the validity of the simulated results. Moreover, the influence of steel ratio, axial compression ratio and shear span to depth ratio on the bearing capacity of composite shear wall was studied. The results showed that the composite shear wall has good mechanical performance. Steel ratio and shear span to depth ratio had remarkable influence on the bearing capacity of the composite shear walls.
Study on the shape of super-high face rockfill dam with sloping compound structure
Authors: Lu Xi , Zhou Heng , Liu Jing , Di Shengjie , Zhang Ying
Published: June 2021

In order to solve the problems of large deformation and difficult maintenance of the super-high face rockfill dam, this paper innovatively proposes the slope-attached compound structure face rockfill dam. The difference between this dam and conventional rockfill dam is that a certain height of slope-attached concrete is set upstream of face rockfill dam. The finite element method is used to demonstrate the shape of the new structure, and the stress and deformation safety of the slope structure, face plate and rockfill dam are analyzed and evaluated. The research results show that it is feasible to set a certain height of sloping concrete in the upstream of the face rockfill dam, and it is also feasible to set a maintenance and drainage corridor in the slope, and this structure can effectively improve the safety and emergency maintenance conditions of the face rockfill dam.
Vibration test study on aeolian sand filler of existing slab culvert strengthened by corrugated metal pipe
Authors: Chen Hongyu , Yuan Xizhong
Published: June 2021

Inadequate structural bearing capacity has appeared in the Reinforced Concrete (RC) slab culverts in permafrost regions of China which have experienced degradation, and need to meet new codes or standards. Based on the method of strengthening for culvert structure by the corrugated metal pipe (CMP), in this paper, shaking table test and vibration box test were introduced to study the vibrational compactness of aeolian sand filled in the small space between the CMP and existing culvert. The results show that aeolian sand in drying or near saturation can be better compacted; aeolian sand with a higher water content has a lower optimum vibration frequency; the sand within 0.6 m from the vibrator can be effectively compacted and 0.4m is the best; in the vibration frequency range of 50~110 Hz, the modulus of aeolian sand decreases as the frequency increases.
Corrosion Behavior of Al-Mn-RE Alloy for Air Conditioning System
Authors: Xiao Gui’Hui , Shi Feijiong , Zhu Mingshan , Shi Jianguo , Liu Jianmin , Hu Xiaohu
Published: June 2021

The effects of RE content and cold rolling and annealing on the microstructure and corrosion resistance of Al-Mn-RE alloy were studied by means of metallographic microscope, scanning electron microscope and electrochemical workstation. The results show that the eutectic phases with different sizes and irregular shapes can be seen in Al-Mn-xRE alloys. With the addition of different RE content, the amount of eutectic silicon increases, the long strip eutectic structure fines and gradually turns into spherical or short rod-like structure. When RE content reaches 0.25% or more, the eutectic structure begins to coarsen. With the increase of RE content, the corrosion potential and pore size of Al-Mn-xRE alloys increase. The corrosion potential of Al-Mn-0.18RE alloy shows a trend of positive and negative migration first, and the corrosion current density decreases first and then increases, the maximum corrosion resistance is obtained when the RE content is 0.18%. The order of corrosion potential and pitting corrosion potential of Al-Mn-0.18RE alloy from high to low is: homogenized state> cold rolled + 325 °C annealed state> rolled state> cold rolled + 475 °C annealed state. The corrosion resistance of the Al-Mn-0.18RE alloy after rolling is lower than that of the homogenized state, but the subsequent stabilization annealing treatment at 325°C can improve the corrosion resistance.
Optimization for the degradation of food waste by a novel anti-acidification and salt-tolerant microbial consortium
Authors: Meng Qingbo , Gao Yude , Li Shuangke , Jiang Bini , He Mingfei , Bu Hao , Wang Hongling , Wu Di
Published: June 2021

Improving the microbial degradation capacity of food waste (FW) is a great challenge due to its acidity and high salinity. In this paper, an anti-acidification and salt-tolerant microbial consortium (AASTMC) obtained from acid and salinity mutagenesis of Bacillus amyloliquefaciens,
Bacillus cereus, Yarrowia lipolytica, and Trichoderma reesei was used to degrade residential food waste. The process parameters that influenced the degradation rate of organic matter were identified by response surface methodology (RSM) with a central composite design (CCD). The effect of inoculation amount, temperature, and bulk density on the degradation rate of organic matter decreased in turn. The degradation rate of organic matter reached 94.87% under the optimum parameters of inoculation amount: 5%, bulk density: 0.04 g/cm3, and temperature: 32.33°C.
Research on influence factors and control methods of backfill compactness
Authors: Li Yudian , Dong Jiajie , Fei Kai , Song Hao , Li Zeyi , Zhang Lintao
Published: June 2021

With the accelerating process of urbanization in China, civil engineering construction develops steadily, building modeling is very different, and the trend of functional diversification is gradually revealed. As the basic process of construction engineering, the quality of earthwork backfill plays an important role in engineering construction. If the quality of the backfill cannot meet the design requirements, the surface subsidence will affect the appearance of the building and cause quality defects, and the insufficient bearing capacity and uneven compaction of the backfill will cause quality accidents such as the inclination of the main structure or structural cracking. In this paper, taking a certain engineering earthwork backfill project as an example, through the dismantling of the construction process of backfill, from the source of backfill soil to the control of backfill quality process, using the measured data to analyze and study the factors affecting the compactness of backfill. The results show that the main factors affecting the compactness of backfill are soil particle size, moisture content, compaction thickness and compaction times. Through the experimental study, the targeted quality control measures are put forward to ensure that the overall quality of the construction project meets the design requirements.
An Approximation Solution to Estimate the Ultimate Bearing Capacity of Smooth Strip Footings on Ponderable Soil
Authors: Han Dong-Dong
Published: June 2021

The procedure for calculating the bearing capacity of smooth footings is employed to calculate the bearing capacity of strip foundations on general c-φ-γ soil by the method of characteristics. The numerical results are in good agreement with other known computations. The surcharge ratio, λ, is found to be another good parameter for evaluation of the bearing capacity without superposition. The approximate formula for estimating the bearing capacity factor Nγ is then proposed considering the influence of λ in addition to φ with an error of no more than ±3 % compared to the numerical results. The error caused by the superposition method is systematically analyzed and the influences of λ and φ on the superposition error are discussed.
Finite element analysis of flexural properties of recycled concrete beams with different content of nickel slag
Authors: Xiong Rui , Jin Songhao
Published: June 2021

Through ANSYS finite element simulation analysis, the influence of different amounts of nickel slag on the mid-span bending moment and deflection of recycled concrete beams under the initial cracking and yielding state is studied. The results show that with the increase of nickel slag content, the flexural performance of recycled concrete beams first increases and then decreases, and there is an optimal nickel slag content. When the nickel slag content is 94kg/m3, the nickel slag has the least effect on the bending performance of the beam. The bending performance of the nickel slag recycled concrete beam is similar to that of the ordinary beam using 100% cement, and it can be used in concrete bending members. Effectively use nickel slag to save resources and protect the environment.
Seismic numerical evaluation of GFRP beam-column joints connected by angle steel with slotted-hole
Authors: Yin Xiangdong , Xiao Xiao , Wang Yan , Yang Shulan
Published: June 2021

This paper is based on the ABAQUS finite element simulation software to study the seismic performance of the glass fiber reinforced polymer (GFRP) beam-column joint connected by the slotted-hole angle steel. Non-linear finite element analysis for the effect of slotted-hole on GFRP beams and different slotted-hole sizes on the seismic performance of joints were conducted. Four specimens D1, D2, D3 and D4 with different slotted-hole lengths were designed. The moment-rotation hysteretic curve, skeleton curve and energy dissipation curve of the specimen are obtained. The finite element analysis results show that: 1) the energy consumption of the slotted-hole joint is about 4%-21% higher than that of the ordinary circular hole joint. 2) The longer the slotted holes length is, the better the seismic energy dissipation performance is. The energy dissipation capacity increases by 3%-12% for each 2 mm increase in the slotted-hole length. 3) Although the larger the slotted-hole length is, the better the energy consumption is, the larger the deformation of the component will be caused. Therefore, according to the requirements of serviceability limit state, it is suggested that the slotted-hole length should be between 2 mm and 4 mm.
Analysis of mechanical behavior of primary lining in double-arch tunnel based on distributed fibre optic monitoring
Authors: Sui Yi , Cheng Xiaohui , Liu Kunjue , Pu Lijian , Li Cande
Published: June 2021

Cracking and crushing were observed in the first tunnel lining of the Kaidagu double-arch tunnel (China), excavated in weathered surrounding rock. This concrete damage occurred during excavation of the second tunnel. It was necessary to monitor the continuous strain distribution along the entire cross section of the lining. Optical fibres were attached to the inner and outer surfaces of the steel arch (primary lining) of the first lining, and monitoring was carried out during the second tunnel excavation. The overall strain distribution was obtained by the fibre optic monitoring, and the internal force and external load distribution of the primary lining were calculated using the proposed inversion analysis method. The calculation results indicated that the axial compression between the right arch shoulder and the right arch foot decreased, which could cause the internal forces of the middle partition wall to increase. The damage mechanism of the lining was inferred. For the first time, optical fibres were installed inside the lining instead of on the inner surface, and the inverse analysis method, which considered the combined effect of axial force and bending moment, was applied to the mechanical analysis of the primary lining. The calculations and analyses provided valuable information for the design and construction of similar projects.
Study on traffic flow characteristics of multi-lane freeway tunnel
Authors: Guo Da , Deng Xiaohua , Song Shenyou , Jiao Chengwu
Published: June 2021

The characteristics of traffic flow are recognized by studying the traffic flow variation law of multi-lane tunnel, which provides theoretical support for the management and control of multi-vehicle tunnel on expressway. By collecting traffic flow data of typical multi-lane tunnel, the relationship among running speed, traffic volume and mixing rate of large vehicles is analyzed. It is found that the inner lane has the highest speed, and the outward lane decreases successively. The higher the speed, the greater the speed difference between vehicles; The lower the mixing rate of large vehicles, the greater the velocity difference between vehicles; There is a negative correlation between the speed and the mixing rate of large vehicles. Finally, combined with the traffic volume and the mixing rate of large vehicles, the speed control strategy for different lanes is proposed.
3D DEM simulation of initial anisotropy in dredger fill soft soil
Authors: Song J , Yang S Y , Zhao Z , Huang X , Liu R H
Published: June 2021

The initial anisotropy has a significant effect on the mechanical properties of the soft soil. Based on the initial anisotropy of the particles, the mechanical characteristics are analysed from a microscopic view, and the micro-macro relationship of the soil is established. According to the particle morphology of soft soil, the discrete element method is used to construct the flaky particle clusters, and seven sets of samples with different initial deposition angles are established for consolidation and undrained triaxial simulation tests. The results show that the strength of the sample decreases first and then increases with the increase of the deposition angle. When the deposition angle is 0°, the flaky particles mostly appear in a nearly horizontal suspension, and the sample has the largest shear strength. The distribution of the contact force chain formed by the particles in the shearing process is also related to the deposition angle. Different deposition angles form displacement fields of different shapes. When the deposition angles are 45° and 60°, there are obvious deformation displacement bands. At the same time, the initial deposition angle affects the particle coordination number. The higher the sample strength corresponding to the lowest average coordination number of particles. The contact normal anisotropy coefficient is related to the strain hardening and strain softening characteristics in the shearing process. The increase in the contact normal anisotropy coefficient shows the characteristics of hardening, and the smaller the contact normal anisotropy coefficient shows the characteristics of softening.
Thermal conductivity and shrinkage properties of slag-based cement concretes
Authors: Zhao Jun , Shumuye Eskinder Desta , Wang Zike
Published: June 2021

The thermal conductivity, specific heat, and total drying shrinkage test of slag blended OPC cement is conducted by using a Hotdisk-2500S thermal conductivity, and non-contact shrinkage deformation measurement apparatus based on ISO 22007-2 and GB/T50082-2009 test standards, respectively. The influence of replacement rates of slag cement (0, 30, 50, and 70%) and high-temperature exposure (21, 200, 400, 600, and 800 °C) on the thermal properties of concrete is analysed. The results show that for all three concretes, the thermal conductivity initially decreases with increasing temperature up to 400 °C, then after it remains almost constant between 400 and 600 °C, and gradually begins to decrease again up to 800 °C. Furthermore, thermal diffusivity of concrete group G-70, shows 21.4, 21.6, and 37.6% increment in 21, 200, and 600 °C temperature exposure respectively compared to concrete group G-0. Though, as the exposure temperature keeps rise to 800 °C, its value starts to decrease. Furthermore, the results indicated that high volume slag cement content in the concrete mix lessen the drying shrinkage of the concrete at later age. Test data is used as a function of temperature and slag replacement to establish high temperature relations for thermal properties. The proposed thermal property relationships can be used as input data for validation in computer programs and to evaluate the response of OPC and slag blended Portland cement concrete structures subjected to fire.
Analysis of Asphalt Aging Behavior Evaluation Method Based on Infrared Spectrum
Authors: Liu Linlin , Lu Yong , Liu Aihua , Li Yali , Guo Ruyong
Published: June 2021

In order to analysis under microscopic scale fast evaluating asphalt asphalt aging mechanism and aging degree, Fourier transform infrared spectroscopy were used respectively to solvent method and ATR method to transmission spectra analysis of matrix asphalt, secondly by ATR method of matrix asphalt tested functional characteristics before and after the RTFOT aging, qualitative and quantitative analysis of the functional groups. The results show that there is no difference between the infrared spectra of the solvent method and the ATR method. Some carbon and sulfur elements in asphalt are oxidized to form carbonyl C=O and sulfoxide S=O functional groups during the aging process, and the oxidation of sulfur element is the main one. The sulfoxide index (SI) and carbonyl index (CI) are well correlated with the penetration degree of asphalt, the correlation coefficient reaches 0.83 and 0.84, respectively. The aging of asphalt increases the sulfoxide index (SI) and carbonyl index (CI), and the asphalt becomes hard and the penetration degree decreases. Infrared spectroscopy can effectively evaluate the aging behavior and degree of asphalt, which provides a new method for rapid detection of aging asphalt.
Analysis of the Necessity for Steel Changing Brace Erection During the Foundation Pit Excavation in Metro Station End Shaft
Authors: Guo Wang , Zhao Junyan
Published: June 2021

Under the engineering background of end shaft construction in an underground two-story metro station, the change and development laws of supporting axial force, enclosure structural deformation and internal force during the end shaft excavation process were analyzed through the field measurement, and the measured values were statistically compared with the design values. The results indicate that it is very necessary to erect steel changing brace in the design, which exerts an unobvious effect on mitigating the enclosure structural deformation of the foundation pit in practical engineering, but apparently affects the axial force of adjacent steel braces in the steel changing brace. The results can be verified through the long-term monitoring at different points during the subsequent metro construction, and other steel changing brace forms convenient for the construction should be considered to substitute the conventional steel changing brace.
Research on the Evolution of Island Coastal Wetland Landscape Pattern
Authors: Wang D G , Dou Y J , Shi A Q , Cheng J , Lv D A
Published: June 2021

The wetland landscape in Ximen Island National Special Marine Protection Area, Zhejiang Province, was adopted as the study object. Remote sensing images in 2006, 2012, and 2017 were interpreted, and landscape indexes, such as the number of patches (NP), largest patch index (LPI), cohesion (COHESION), division, patch density (PD), Shannon diversity index (SHDI), Shannon equilibrium index (SHEI), and landscape shape index (LSI), were used to monitor and analyze the evolution of the coastal wetland landscape pattern on Ximen Island. Results showed that during 2006–2017, the wetland aquiculture area around Ximen Island presented a gradual decrease from 785 hectares to 712 hectares. The wetland vegetation area increased from 292 hectares to 467 hectares, and the area added was transformed from wetland aquiculture and naked mudflat. Total NP and PD decreased from 1,444 to 1,298 and from 60.3 to 52.2, respectively. From the angle of LSI, SHDI and SHEI gradually increased from 1.2515 to 1.358 and from 0.7776 to 0.8432, respectively, indicating a uniform landscape distribution in the wetlands. The COHESION index increased from 97.9281 to 98.26, manifesting a concentrated landscape distribution in the wetlands. The LSI in the protection area declined from 20.6717 to 18.512, showing that the wetland landscape shapes were regular in the protection area.
Study on the Development Strategy of Tourism City Planning in Harbin under the Background of New Urbanization
Authors: Zhao Hengyu , Shi Xiuhua
Published: June 2021

Tourism urbanization has become one of the important paths of urban planning, but also the development of low-carbon economy and ecological new measures, is the only way for urban sustainable development. Tourism-oriented urban development is a process in which urban planning changes from industry and agriculture to tourism under the background of new urbanization. Based on the study of new urbanization and tourism-based urbanization, this paper analyzes the tourism-based urbanization of Harbin in combination with the development characteristics of Harbin and the successful cases of some characteristic towns, and provides new development strategies for urban planning of Harbin, and strives to transform the tourism-based urbanization construction of Harbin into a new driving force to stimulate economic growth and ecological construction.