bluuebunny/crossref_metadata_2025 huggingface dataset:
Large metal halide perovskite crystals for field-effect transistor applications
Authors: Matsushima Toshinori , Leyden Matthew R. , Fujihara Takashi , Qin Chuanjiang , Sandanayaka Atula S. D. , Adachi Chihaya
Published: September 2019

The material 2-phenylethylammonium tin iodide perovskite (C6H5C2H4NH3)2SnI4 [abbreviated as (PEA)2SnI4] has shown promising performance as a polycrystalline semiconductor for field-effect transistors (FETs). However, grain boundaries and structural disorder in polycrystalline films limit performance, and so the fundamental upper bounds of the material are yet to be studied. Here, we prepared large crystals of (PEA)2SnI4 for FETs and demonstrated carrier mobilities of 40 cm2 V−1 s−1 or higher, although with a low fabrication yield (< 1%). Our crystal FETs were very stable when stored in air and when operated under a bias in vacuum. The FET characteristics were superior to those of reported FETs based on polycrystalline perovskite films, and these results contribute to a better understanding of basic carrier transport mechanisms in hybrid perovskite materials.
High-performance room-temperature TiO2-functionalized GaN nanowire gas sensors
Authors: Shi Chen , Rani Asha , Thomson Brian , Debnath Ratan , Motayed Abhishek , Ioannou Dimitris E. , Li Qiliang
Published: September 2019

Hybrid gas sensors based on TiO2 functionalized gallium nitride nanowires have been prepared by nanofabrication and comprehensively studied for high-responsivity applications. The devices exhibited a high responsivity (25%) to 500 ppm NO2 assisted with ultraviolet illumination at room temperature. The thickness and doping concentration of TiO2 were engineered to improve the transducer function. The result indicated that an excellent n-type response can be stably obtained for a doping range from 1 × 1017 cm−3 to 1 × 1019 cm−3. The TiO2 thickness and doping concentration can be further fine-tuned to achieve optimal performance. In addition, a comprehensive device simulation was carried out to understand the device operation and gain insight for optimizing the device performance.
Semilocal exchange-correlation potentials for solid-state calculations: Current status and future directions
Authors: Tran Fabien , Doumont Jan , Kalantari Leila , Huran Ahmad W. , Marques Miguel A. L. , Blaha Peter
Published: September 2019

Kohn-Sham (KS) density functional theory (DFT) is a very efficient method for calculating various properties of solids as, for instance, the total energy, the electron density, or the electronic band structure. The KS-DFT method leads to rather fast calculations; however, the accuracy depends crucially on the chosen approximation for the exchange and correlation (xc) functional Exc and/or potential vxc. Here, an overview of xc methods to calculate the electronic band structure is given, with the focus on the so-called semilocal methods that are the fastest in KS-DFT and allow to treat systems containing up to thousands of atoms. Among them, there is the modified Becke-Johnson potential that is widely used to calculate the fundamental bandgap of semiconductors and insulators. The accuracy for other properties like magnetic moment or electron density, that are also determined directly by vxc, is also discussed.
Apparent repulsion between equally and oppositely charged spherical polyelectrolytes in symmetrical salt solutions
Authors: Lin Cheng , Zhang Xi , Qiang Xiaowei , Zhang Jin-Si , Tan Zhi-Jie
Published: September 2019

Ion-mediated interactions are very important for the properties of colloids and biomacromolecules such as nucleic acids and proteins. In this work, the ion-mediated interactions between equally and oppositely charged spherical polyelectrolytes (SPEs) in symmetrical divalent electrolytes have been investigated by Monte Carlo simulations, and an unexpected apparent repulsion was observed at high divalent salt concentration. Our investigations also show that the effective repulsion becomes more pronounced for SPEs with higher charge densities and for counterions with larger sizes and was found to be tightly accompanied with the over-neutralization to SPEs by condensed counterions and their release upon the approach of SPEs. Such attractive interaction can be reproduced by our proposed modified Poisson-Boltzmann model and is mainly attributed to the increase in the electrostatic repulsion between on charged SPE and the over-neutralized counterions around the other oppositely SPE with the approach of the two SPEs.
Nonequilibrium phase transition in constrained adsorption
Authors: Sellitto Mauro
Published: September 2019

We study the adsorption-desorption of fluid molecules on a solid substrate by introducing a schematic model in which the adsorption/desorption transition probabilities are given by irreversible kinetic constraints with a tunable violation of local detailed balance condition. Numerical simulations show that in one spatial dimension, the model undergoes a continuous nonequilibrium phase transition whose location depends on the irreversibility strength. We show that the hierarchy of equations obeyed by multipoint correlation functions can be closed to the second order by means of a simple decoupling approximation and that the approximated solution for the steady state yields a very good description of the overall phase diagram.
The addition of quantum wells to solar cells vastly improves efficiency
Authors: Bandari Anashe
Published: September 2019

A study of the effects of nanostructures on Kesterite solar cells found the theoretical optimum efficiency can be increased beyond the former limit of 29.7% to 43.3%.
Multivariate drivers of diversity in temperate Australian native grasslands
Authors: Price Jodi N. , Good Megan K. , Schultz Nick L. , Guja Lydia K. , Morgan John W.
Published: September 2019

Disturbance has been considered essential for maintaining biodiversity in temperate grassy ecosystems in Australia. This has been particularly well demonstrated for inter-tussock plant species in C4 Themeda-dominated grasslands in mesic environments. Disturbance is also thought crucial to maintain the structure of preferred habitat for some animals. Relationships between disturbance and diversity may be contingent on ecosystem productivity, but little is known about the generality of the disturbance-promoting-diversity paradigm across the range of temperate grasslands. To date, the disturbance-promoting-diversity paradigm has taken a univariate approach to the drivers of biodiversity; rainfall is seen as a key driver of productivity, which then drives diversity, mediated by disturbance. We argue that this framework is too simplistic as biodiversity drivers are multivariate. We suggest that the accumulation of phytomass (live and dead plant material) is an important determinant of diversity in grassy ecosystems and that phytomass accumulation is governed by multiple drivers (of which disturbance is just one). For fauna, it is structure – not biomass – that determines habitat suitability, and this can be moderated by both abiotic and biotic drivers. The assumption that there is a consistent effect of disturbance on diversity through the range of temperate grassland settings in southern Australia ignores the likelihood that biodiversity also responds to other factors such as spatial heterogeneity in the environment, resource availability and climatic variation. We developed a conceptual model of the multivariate drivers of grassland diversity that explores mechanisms underpinning patterns of species richness. Despite four decades of research, it is clear that our understanding of the multivariate drivers of diversity across the range of temperate grasslands in Australia is still incomplete. Further research into the conditions under which disturbance is required to maintain biodiversity in grasslands is integral to conservation planning in these endangered systems.
Microstructural modification of Sn–Bi and Sn–Bi–Al immiscible alloys by shearing
Authors: Cassinath Z. , Li Z. , Sridhar S. , Das A. , Kotadia H. R.
Published: September 2019

Sn–20 wt-%Bi and immiscible Sn–20 wt-%Bi–1 wt-%Al alloys were used to understand the effect of high-intensity shearing on microstructural refinement. Novel ACME (Axial Centrifugal Metal Expeller) shearing device, based on axial compressor and rotor–stator mechanism to generate high shear rate and intense turbulence, was used to condition the melts prior to solidification. Microstructure in the Sn–Bi alloy deviated from dendritic grains with coarse eutectic pockets under conventional solidification to compact grains with well-dispersed eutectic under semisolid-state shearing. Decreasing the shearing temperature and increasing shearing time increased the globularity of grains. Following shearing, remnant liquid solidified into fine grain structure. In the immiscible Sn–Bi–Al alloy, shearing produced uniform dispersion of refined Al-rich particles in Sn-rich matrix as opposed to severe segregation under conventional solidification. The primary effect of shearing appears to originate from the thermo-solutal homogenisation of the melt and its effect on interface stability during solidification.
Systematic characterization of extracellular vesicle sorting domains and quantification at the single molecule – single vesicle level by fluorescence correlation spectroscopy and single particle imaging
Authors: Corso Giulia , Heusermann Wolf , Trojer Dominic , Görgens André , Steib Emmanuelle , Voshol Johannes , Graff Alexandra , Genoud Christel , Lee Yi , Hean Justin , Nordin Joel Z. , Wiklander Oscar P.B. , El Andaloussi Samir , Meisner‐Kober Nicole
Published: September 2019

Extracellular vesicles (EV) convey biological information by transmitting macromolecules between cells and tissues and are of great promise as pharmaceutical nanocarriers, and as therapeutic per se. Strategies for customizing the EV surface and cargo are being developed to enable their tracking, visualization, loading with pharmaceutical agents and decoration of the surface with tissue targeting ligands. While much progress has been made in the engineering of EVs, an exhaustive comparative analysis of the most commonly exploited EV‐associated proteins, as well as a quantification at the molecular level are lacking. Here, we selected 12 EV‐related proteins based on MS‐proteomics data for comparative quantification of their EV engineering potential. All proteins were expressed with fluorescent protein (FP) tags in EV‐producing cells; both parent cells as well as the recovered vesicles were characterized biochemically and biophysically. Using Fluorescence Correlation Spectroscopy (FCS) we quantified the number of FP‐tagged molecules per vesicle. We observed different loading efficiencies and specificities for the different proteins into EVs. For the candidates showing the highest loading efficiency in terms of engineering, the molecular levels in the vesicles did not exceed ca 40–60 fluorescent proteins per vesicle upon transient overexpression in the cells. Some of the GFP‐tagged EV reporters showed quenched fluorescence and were either non‐vesicular, despite co‐purification with EVs, or comprised a significant fraction of truncated GFP. The co‐expression of each target protein with CD63 was further quantified by widefield and confocal imaging of single vesicles after double transfection of parent cells. In summary, we provide a quantitative comparison for the most commonly used sorting proteins for bioengineering of EVs and introduce a set of biophysical techniques for straightforward quantitative and qualitative characterization of fluorescent EVs to link single vesicle analysis with single molecule quantification.
A THEORY OF INJURY AND RECOVERY
Authors: Osterhout W. J. V.
Published: September 2019

On page 150, Vol. iii, No. 2, November 20, 1920, line 18, for The resistance after, etc., read The resistance due to A and M after, etc.; line 20, of the same page, equation (4) should read as follows:

See PDF for Equation

page 151, line 11, equation (5) should read as follows:

See PDF for Equation

line 16, of the same page, for the value of O is 92.57 read the value of O is 82.57; lines 16 and 17, of the same page, for (92.57 – 10) ÷ (100 – 10) = 0.917 read (82.57) ÷ (90) = 0.917.
A new temporal control approach for SCAO systems
Authors: Pöttinger Markus , Ramlau Ronny , Auzinger Günter
Published: September 2019

Adaptive optics (AO) systems for ground-based telescopes use deformable mirrors to physically correct wavefront distortions induced by atmospheric turbulence. Due to time delays caused by different parts of the AO system, the process of turbulence correction becomes even more difficult since the earth’s atmosphere changes continuously. In this paper we propose a new temporal control approach for the computation of optimal mirror configurations based on the solution of a sequence of inverse problems for the wavefront sensor operator. Our mathematical formulation of the underlying problem allows the incorporation of computationally efficient wavefront reconstruction methods and a wavefront prediction step. Based on the frozen flow assumption, the prediction of a future wavefront relies on a suitable shift of the reconstructed wavefront. The performance of our temporal control algorithm is demonstrated in the context of a single conjugate adaptive optics system on a 37 meter telescope using a Shack–Hartmann wavefront sensor. Numerical results of the proposed control method are provided using OCTOPUS, the official end-to-end simulation tool of the European Southern Observatory.
Measurement of PET isotope production cross sections for protons and carbon ions on carbon and oxygen targets for applications in particle therapy range verification
Authors: Horst Felix , Adi Wihan , Aricò Giulia , Brinkmann Kai-Thomas , Durante Marco , Reidel Claire-Anne , Rovituso Marta , Weber Uli , Zaunick Hans-Georg , Zink Klemens , Schuy Christoph
Published: September 2019

Measured cross sections for the production of the PET isotopes

,

and

from carbon and oxygen targets induced by protons (40–220

) and carbon ions (65–430

) are presented. These data were obtained via activation measurements of irradiated graphite and beryllium oxide targets using a set of three scintillators coupled by a coincidence logic. The measured cross sections are relevant for the PET particle range verification method where accurate predictions of the

emitter distribution produced by therapeutic beams in the patient tissue are required. The presented dataset is useful for validation and optimization of the nuclear reaction models within Monte Carlo transport codes. For protons the agreement of a radiation transport calculation using the measured cross sections with a thick target PET measurement is demonstrated.
Effects of deposition temperature on optical properties of MgF2 over-coated Al mirrors in the VUV*
Authors: Guo Chun , Li Bin-Cheng , Kong Ming-Dong , Lin Da-Wei
Published: September 2019

Both long-term environmental durability and high reflectance of protected-Al mirrors are of great importance for developing the optical instruments in the vacuum ultraviolet (VUV) applications. In this paper, the dependence of spectral property and environmental durability of MgF2 over-coated Al mirrors using a 3-step method on deposition temperature of the outermost MgF2 layer are investigated in detail. Optics (reflectance), structure (surface morphology and crystalline), and environmental durability (humidity test) are characterized and discussed. The results show that both optical and moisture-resistant properties of MgF2 over-coated Al mirrors are dependent on MgF2 deposition temperature, and the optimal deposition temperature for the outermost MgF2 layer should be between 250 °C and 300 °C for MgF2 over-coated Al mirrors to have both reasonably high reflectance in the VUV spectral range and high moisture resistance for long lifetime applications.
Disorder induced phase transition in magnetic higher-order topological insulator: A machine learning study*
Authors: Su Zixian , Kang Yanzhuo , Zhang Bofeng , Zhang Zhiqiang , Jiang Hua
Published: September 2019

Previous studies presented the phase diagram induced by the disorder existing separately either in the higher-order topological states or in the topological trivial states, respectively. However, the influence of disorder on the system with the coexistence of the higher-order topological states and other traditional topological states has not been investigated. In this paper, we investigate the disorder induced phase transition in the magnetic higher-order topological insulator. By using the convolutional neural network and non-commutative geometry methods, two independent phase diagrams are calculated. With the comparison between these two diagrams, a topological transition from the normal insulator to the Chern insulator is confirmed. Furthermore, the network based on eigenstate wavefunction studies also presents a transition between the higher-order topological insulator and the Chern insulator.
Development and validation of a suite of standards for the purity assignment of organic compounds by quantitative NMR spectroscopy
Authors: Westwood Steven , Yamazaki Taichi , Huang Ting , Garrido Bruno , Ün Ilker , Zhang Wei , Martos Gustavo , Stoppacher Norbert , Saito Takeshi , Wielgosz Robert
Published: September 2019

The evaluation of seven internal standard reference materials (ISRMs) to act as a ‘universal’ SI-traceable calibrator suite for organic compound purity determination by quantitative nuclear magnetic resonance (qNMR) spectroscopy is described. The set of compounds demonstrated to constitute such a suite are: potassium hydrogen phthalate (KHP), maleic acid (MA), 3,5-bis-trifluoromethyl benzoic acid (BTFMBA), dimethyl sulfone (DMSO2), dimethyl terephthalate (DMTP), 1,4-bis-trimethlsilyl benzene (BTMSB or BTMSB-d
4) and perdeuterated sodium 3-trimethylsilyl-1-propanesulfonate (DSS-d
6). The compounds were selected such that at least one ISRM should be suitable for use as the internal standard for the qNMR purity assignment of an organic compound soluble in a given deuterated solvent. They allow for the selection for use as the internal reference for quantitative integration from a set of simple, sharp NMR signals dispersed over the proton chemical shift range.

Optimized conditions for acquiring qNMR spectra were developed and are described, as well as the results of an extensive series of studies validating the use of the ISRM suite to assign mass fraction values in four representative solvents (D2O, DMSO-d
6, CD3OD and CDCl3). Proper use and application of these ISRMs result in standard uncertainties in the assigned values of the analyte of interest of the order of 1 mg g−1 in optimal cases. These materials are of particular interest for the mass fraction purity determinations by qNMR of organic compound reference materials required as analyte specific calibrators to underpin the SI-traceability of the results for routine laboratory analysis based on techniques such as gas and liquid chromatography.
Leakage and boosting effects in environmental governance: a framework for analysis
Authors: Bastos Lima Mairon G , Persson U Martin , Meyfroidt Patrick
Published: September 2019

In an increasingly interconnected world, leakage—broadly understood as unintended displacement of impacts caused by an environmental policy intervention—has become a major governance concern. Yet, leakage remains both loosely conceptualized and poorly understood as a phenomenon in policy making. To fill this gap and broaden the leakage research agenda, we conduct a state-of-the-art review of scientific assessments on leakage (particularly on land use) and combine it with conceptual and analytical frameworks from the environmental governance literature. We then propose a rigorous definition of leakage, discuss frequently overlooked political dimensions, and develop a typology of leakage pathways. Our analysis of leakage through a governance lens yields five core insights: (1) Leakage is not simply a mechanistic phenomenon, but a complex governance issue involving questions of institutional fit, interactions, and political agency. (2) Although the land use literature traditionally focuses on leakage through markets or activity displacement, a governance lens shows that it also occurs through information, motivation, or institutional channels. (3) As policy-makers may act strategically, the unintentionally of leakage should not be assumed but rather become an object of research. (4) A phenomenon not initially regarded as leakage can come to be framed as such through the action of ‘problem brokers’ and changes in policy fields. (5) Policy-makers and researchers should broaden their focus from only avoiding leakage to seeking positive spillovers and institutional synergies. These insights are illustrated with examples from two cases relating to land use policy in Brazil and Southeast Asia.
Numerical simulation on temperature of water released from multi-level intake of reservior
Authors: Shaoxiong Zhang , Wenzhi Cui , Liting Zhang , Xiang Gao
Published: September 2019

In order to reduce the negative effect of lower water temperature released from the intake to the salmon in the downstream of the river, a multi-level intake was adopted in Glen Canyon Dam. Based on three-dimensional numerical model EFDC, this article simulated the water temperature under different discharge and open combination, obtained the effect law of discharge and open combination on temperature of water released. The results show that the temperature released increases slightly with the increase of the single diversion flow rate. The effect on the temperature released is very small when the intake opens in different combinations.
Study on the Riverbed Evolution under the Condition of Clear Water Flushing
Authors: Xiaobing Cheng
Published: September 2019

Water flow downstream of the hub is clear, and the riverbed scouring is large, which affects the navigation depth of the channel. In this paper, the flume experiment is carried out to study the degree of undercut of the riverbed under the action of clear water scouring, the change of the particle size of the bed load, the decrease of the water level and the change of the sediment transport rate along the channel. The results show that the initial channel of the lower reaches of the hub is eroded. With the deepening of the riverbed, the bed material is coarsened and the erosion is gradually weakened, and the later flushing rate is gradually constant. The inlet water level in the sanding section first drops steadily and then gradually stabilizes. The water transport rate along the channel is a power function relationship with time. In the power function relationship, there is a balanced sediment transport period.
Models of Hydraulic Factors Analysis Based on Genetic Programming for South-to-North Water Diversion Middle Route Project
Authors: Chen Xiaonan , Chen Haitao , Jin Yanguo , Feng Xiaobo , Ma Yanjun , Guo Fang
Published: September 2019

The South-to-North Water Diversion Middle Route Project has long water transmission line, complicated operation conditions for water conservancy dispatch, and high water diversion demands. It is important to calculate and analyse the correlation among hydraulic factors for water diversion. At present, the traditional hydraulic empirical formulas are used to evaluate relation of hydraulic elements in Middle Route Project, the parameters need to be manually corrected by measured data during operation, and the flexibility is poor. Model based on genetic programming is suggested for data mining of water conveyance dispatch. Correlativity function can be established automatically by genetic operations including selection, crossover and mutation. The model is applied into the discharge calculation and analysis of water surface curve for typical gate station and canal pool in Middle Route Project. In discharge calculation, the relation function between head difference, gate opening and flow coefficient can be found automatically with genetic programming. Similarly, the relation between downstream water depth, flow and upstream water depth can be achieved by the suggested model. It is shown that the proposed model based on genetic programing would be effective in nonlinear regression for hydraulic factors.
Experimental Study on the River Engineering Model of Shuangliu Bridge across Yangtze River in Wuhan
Authors: Hui Zhang , Xinyuan Liu , Huiyun Li
Published: September 2019

Shuangliu Bridge across Yangtze River in Wuhan was the key control project of Xingang Expressway. It was the way to cross the river for the construction of Xingang Expressway. The bridge was located at the junction of the exit of Yejiazhou River Section and the entrance of Tuanfeng River Section. The upstream was 26.5 kilometers from Yangluo Expressway Bridge of Yangtze River, and the downstream was 21 kilometers from Huanggang Bridge of Yangtze River. Based on analysis of evolution of riverbed and the experiment of river engineering model, not only evolution rules of a river channel of the section at the bridge site after the application of the Three Gorges Reservoir were specially studied, but also the change rules before and after the construction of the bridge were also studied such as the damming at the upstream section of the bridge site, the current velocity and flow direction of the upper and lower reaches, the discharge of the single wide at the bridge site, and the distributary ratio of a branch channel of the lower reaches of the Tuanfeng River, etc. It showed the two bridge schemes had no great influence on river regime and flood control of engineering reach, and a double-tower cable-stayed bridge was better than a three-tower cable-stayed bridge. The results can be adopted or referenced to designing project.
Research on Criterions of Hydraulic Fracturing in Earth Core Rockfill Dams
Authors: Ji Enyue , Chen Shengshui , Fu Zhongzhi
Published: September 2019

Hydraulic fracturing is an important destruction mode in the earth core rockfill dam engineering. In this paper, to explicit the mechanism of hydraulic fracturing and thus to verify the existing criterions, hydraulic fracturing tests were conducted based on true triaxial apparatus. Additionally, the precision of initial fracturing water pressure calculated by existing criterions is compared respectively. It is proved that the tensile strength and fracture initiation pressure pf all increase with the increasing of dry density. pf shows linear relationship with the minor principal stress σ3. The crack of hydraulic fracturing existed perpendicular to the minor principal stress plane. In addition, for T-S criterion, the predicted values are all less than the test data. On the contrary, most of the predicted values from M-C criterion are greater than the test data. Considering the safety of ECRD engineering, T-S criterion is suggested to predict the occurrence of hydraulic fracturing
After the Three Gorges Project to use the impact analysis by scouring and silting in Poyang Lake control engineering area
Authors: Gong Ping , Wang Min
Published: September 2019

Lake control project of Poyang lake is a large scale with a complex operation scheduling, which has an effect on the flood control and environment near the connected area between Poyang lake and Yangtze river. This paper combines one-dimensional and two-dimensional water and sediment mathematical model to calculate and analyze it. The application of a long reach and long term one-dimensional mathematical model from Yichang to Datong provides boundary conditions for the two-dimensional model. Two-dimensional model between part of Yangtze river and Poyang lake is used to calculating the influence caused by lake control project to the bed erosion and deposition between the river and lake after the operation of Three Gorges Reservoir. The research result shows that after a 10-year operation of lake control project, riverbed scouring takes place on a large scale near the connected area as long as the point bar which used to be deposit, and the deepest erosion on bed groove reaches about 1.3m. Sediment scouring takes place on the Yangtze river under the lower Zhangjiazhou channel, but the upper channel changes less relatively.
Study on Compaction Construction of Special Cushion in Altas Hydro Project
Authors: Tan Fengyi , Hu Lin , Chen Libo , Tang Desheng , Ren Haijun
Published: September 2019

The special cushion of the concrete face rockfill dam in Altas Hydro Project was mainly between the dam body and surrounding mountains whose compaction construction had the following characteristics: (1)the small and irregular construction site, (2)the very strict requirement of construction technology. Therefore there were series of in-situ tests to verify the designed rationality of compaction standard of special cushion materials, then the compaction construction technology and related construction parameters was advised, at last, the permeability property of special cushion materials and its compaction construction after sprinkling and soaking was discussed.
Beach and Trough Stability Study of the Xiyang Sea Area of Jiangsu Province
Authors: Jun Chen , Fan Zhu
Published: September 2019

The dynamic geomorphology of the Xiyang sea area, the largest tidal channel in the northern part of the Radial Sand Ridges in the South Yellow Sea, is complex. This paper studies the tidal flat and tidal channel stability and the evolution of the coast off the Xiyang sea area by combining topographic surveys in different periods with the data from remote sensing satellites. The result shows that the state of west tidal flat of the Xiyang tidal channel has changed from long-term siltation to dynamic balance of erosion and siltation. The Dongsha Sand Ridges on the eastern side of the Xiyang tidal channel has moved eastward and southward. The exchange of water and sand in the seas of Piaoersha and Sanyazi sand ridges was frequent with no significant rules of erosion and siltation.
Effect of honeycomb bulkheads on uniaxial undrained bearing capacities of wide-shallow bucket foundation
Authors: Wang Qingshan , Cao Yongyong , Han Xun , Li Wenxuan
Published: September 2019

In order to study the effect of honeycomb bulkheads on uniaxial undrained bearing capacities of wide-shallow bucket foundation, the finite element models of bucket foundations with and without bulkheads on soft ground were established respectively. A large number of 3D finite element analyses have been performed to obtain uniaxial bearing capacities of the two foundations with different embedment ratios and soil shear strength heterogeneity by using displacement control method. The results show that, for homogenous clay, all the vertical, horizontal and moment bearing capacities of the wide-shallow bucket foundation are not affected by the honeycomb bulkheads. For non-homogenous clay, the moment bearing capacity of the wide-shallow bucket foundation is obviously affected by the honeycomb bulkheads, while the effect for improving the vertical and horizontal bearing capacity of the bucket foundation can be neglected. For the convenience of designers reference, simplified calculation equations for undrained bearing capacities are fitted according to the finite element results.
Construction Control Method and Application of Hydropower Project Based on Permanent and Temporary Monitoring
Authors: Zhao Daipeng , Zhan Qinghua , Li Hua , Pan Hongyue
Published: September 2019

According to the permanent and temporary monitoring results, the warning boundary method and the mathematical physical model method are used for early warning and forecasting, and the construction measures are dynamically adjusted to form a construction control method based on safety monitoring technology. The application of the method which combines permanent monitoring with temporary monitoring on the front slope of the tail water outlet of the left bank, the upstream side wall of the 7#∼8# machine on the right bank, and the downstream abutment of the 9#∼10# unit section of Wudongde Hydropower Station, shows that it can fully grasp the stability of surrounding rock during construction period of slope and underground caverns. Through the early warning and forecasting, the mechanism of deformation is analyzed, the construction measures are adjusted in time, and the effect of the measures is evaluated, which plays an important role in ensuring the safety of the construction period.
Ecological footprint and carrying capacity change analysis on Yan’an water resources
Authors: Zhao Yifei , Wang Ping , Li Ying
Published: September 2019

Based on the water resource data and economic data from 2006 to 2017, this paper analyzes the temporal and spatial variation characteristics of sustainable water resources utilization in Yan’an, using a water ecological footprint model and the ten-thousand-yuan GDP water resource ecological footprint, combined with the ecological carrying capacity and ecological deficit principle. The result shows that the overall wave of the water resources ecological footprint in Yan’an rises but not in an obvious way, but the ecological carrying capacity and the ecological deficit of water resources are fluctuating. Production water accounts for the largest proportion in the water resources ecological footprint. Affected by industrial transformation, the industrial water consumption in Yan’an has increased year by year and ranked the first by exceeding agricultural irrigation water in 2009. The ecological footprint of water resources in Yan’an has always been greater than its ecological carrying capacity, and the water supply has been in an ecological deficit state; in general, the ten-thousand-yuan GDP water resources ecological footprint has decreased obviously, while the resource utilization has gradually been increasing. However, consumption on water resources by economic development is still faster than resource regeneration.
Evaluation of River Health from the View Angle of ‘the New Vision for Development’
Authors: Su Pengcheng , Liu Bo , Cui Jinyu , Yi Han
Published: September 2019

Along with the rapid development of China’s economy, environmental problems such as water pollution have been prominent. Hence, ‘the New Vision for Development’ was proposed. ‘The New Vision for Development’ complies with the trend of development in today’s world and puts forward new requirements for the development of China nowadays. Meanwhile, the introduction of river health assessment has promoted the development of river management in China. In order to evaluate river health more scientifically and make river management more efficient, this paper defined the connotation of river health evaluation from the view angle of ‘the New Vision for Development’ and adopted the Pressure-State-Response framework concept to establish an evaluation index system. Then the fuzzy evaluation model was constructed through grey clustering and grey correlation analysis. Finally, the applicability of the method was proved through a case study. The study provides an effective method for river health assessment.
A Research on Tunnel Lining Water Leakage from the Aspect of Operation Influence
Authors: Ding Hao , Jiang Xinghong , Li Ke , Hu Xuebing , Cheng Liang
Published: September 2019

In the early times, restricted by the tunnel construction technology and technical difficulties, tunnel diseases, especially water leakage of lining are widespread in the tunnel engineering of China. Leakage disease would adversely affect the lining structure and operation environment, which may endanger the normal operation of tunnel projects. Existing leakage classification standards for tunnels are mainly based on the apparent view state, and the impacts of the actual operating environment are not fully taken into consideration. Based on the characteristics of leakage influences on tunnels, leakage in tunnels is analysed from the perspective of traffic safety, including the influence on driving safety and the influences of tunnel operation. Through investigation, point out the shortcomings of existing leakage classification methods, such as criteria are not complete, quantitative criteria are insufficient, disease treatment are not considered, and so on. The research results will provide important ideas for future research of tunnel lining leakage.
Spatial-temporal Features of Nitrogen and Phosphorus Losses of Jingui River Watershed in the upstream of Lijiang River
Authors: Pan Linyan , Dai Junfeng , Yu Chenwenjiong , Xie Xiaolin , Wu Zhiqiang
Published: September 2019

To find out the nitrogen and phosphorus concentration and load emission regularity and its effect during the rainy season + irrigation period and dry season + non-irrigation period in the small watershed, five spatial scales (3.35 ∼27.25 km2) nested in the Jingui river watershed are selected and regularly monitored from October 2017 to September 2018. The results showed that the nitrogen and phosphorus concentrations in the rainy season + irrigation period and dry season + non-irrigation period increased with the increase of the scale. The total nitrogen and total phosphorus load per unit area in the rainy season + irrigation period decreased with the increase of the scale; the dry season + non-irrigation period increased slightly. The same nitrogen and phosphorus index concentration was significantly different at different spatial scales. The main reason for the scale effect was the distribution pattern of land-use. Affected by this, scale D, the critical scale of nitrogen and phosphorus load in Jingui river watershed, its average load of total nitrogen, ammonium nitrogen, total phosphorus and total dissolved phosphate reached the highest value of the watershed. The contribution rate of nitrogen and phosphorus load in rainy season + irrigation period and dry season + non-irrigation period of research areas with different area depends on precipitation and the distribution pattern of land-use. Therefore, the nitrogen and phosphorus emission control and pollutant reduction in the rice irrigation districts of Lijiang river basin should consider the spatial-temporal features and effects of nitrogen and phosphorus pollutant transport.
Design and application of sewage treatment process in expressway service area
Authors: Duan Kewu , Ai Chengyuan , Chen Fang
Published: September 2019

In order to improve the efficiency, impact resistance and purification effect of sewage treatment in service areas, the composition and quantity of sewage water quality in expressway service areas were studied. A highway service area in Yunnan Province uses a combined process for sewage treatment, and the scale has been reached 4000m3/d. The specific process is “multi-point water inlet A/O process + denitrification sand filter + phosphorus removal filter + chlorine dioxide disinfection + activated carbon filter”.The actual effluent quality meets the”Discharge standard of pollutants for municipal wastewater treatment plant” (GB18918-2002). And the first-class standard meets the requirements of “The reuse of urban recycling water-Water quality standard for urban miscellaneous water consumption” (GB/T18920-2002). The engineering practice proves that it is completely feasible to use this combined process to treat sewage in the highway service area, which can be used for reference and reference by similar projects.
Calculation models and analysis methods of the parametric vibration of radial gates
Authors: Liu Jiliang , Liu Yunhe , Wang Zhengzhong
Published: September 2019

Parametric vibration is one of the main reasons for the failures of radial gates. This paper presents three calculation models of the parametric vibration of radial gates which reflect the mechanical properties and geometric features of the gates. Two most commonly used analysis methods, i.e., Bolotin’s method and the finite element method, were described to determine the boundaries of regions of the dynamic instability of radial gates. A numerical example concerning finite element method was also demonstrated.
Research on LUCC in Nansi Lake Area Based on GF-1 Image
Authors: Li Qin , Sang Guoqing
Published: September 2019

Based on the high-resolution images of Nansi Lake, the multi-scale segmentation of eCognition and the object-oriented nearest neighbor method are used for classification and visual interpretation and correction.The results show that the classification method is relatively fast, the boundary of the ground class fits natural objects, the classification parameters can be classified based on panchromatic bands, and other spectral bands and indexes can be subdivided.According to the results, the order of land area in the Nansi lake basin is irrigated land > lake region > urban land > aquaculture water surface> paddy field > unused land > navigation channel > forest land > river channel.
Refined characteristics of rainfall in Guangxi area for mountain flood based on hourly precipitation
Authors: Zhou Ning , Zhang Xinxin , Li Hongen , Xu Haifeng , Li Zheng , He Yongjun
Published: September 2019

On the basis of hourly rainfall dataset from 92 meteorological stations for the 10 years (2008-2017), the spatial and temporal distribution of precipitation in Guangxi were analyzed. Results showed that high value precipitation centers were found over different districts during two time frame, 6:00-12:00 and 18:00-24:00. The rainfall over north of Guangxi mainly happened during 18:00-24:00, but over the middle of Guangxi was during 6:00-12:00. The hourly precipitation distributed unevenly on season scale. Seasonal differences in diurnal variation of rainfall were distinguished. Summer rainfall events concentrated at morning, but the events during other three seasons were more likely to happen in the evening. Using empirical orthogonal function (EOF), the first principal component displayed apparent spatial distribution, which would be helpful to classify the security of mountain flood. During the 6:00-12:00, the patterns were more typical to describe the high rainfall centers in summer. As for the other three seasons, the patterns were appropriate during 18:00-24:00.
Research on the methods of BIM reliability prediction with the construction schedule in the application of project of Chushandian reservoir
Authors: Juan Wu , Bingru Zheng , Die Chen
Published: September 2019

With the development of BIM (building information model), based on the existing construction management theory, combined with the idea of intelligent construction, fully integrating BIM and 4D technology, we can realize the optimization of construction schedule and real-time perception and control of the actual progress of construction. In this paper, the design model is built on the basis of 3D digital technology and CATIA software as the carrier. In the Sql Server database management system as the platform, with the use of information management platform data, the 4D BIM model has been formed, and the schedule control system has been applicated in the Chushandian reservoir project, preliminarily implemented schedule monitoring target. Chushandian project application shows that to achieve the progress of data entry, the use of human-computer interaction realized the dynamic simulation of the progress of the interactive query and other data. The comparison of schedule deviation can be achieved by entering the schedule and actual progress into the network database; through the analysis of abnormal records, and the formulation of measures, the realization of schedule can be ensured.
Multi-Objective Optimal Scheduling of Wangwu Reservoir Based on NSGA-II
Authors: Xu Zhen , Li Qingguo , Feng Shiyuan , Li Wanwan
Published: September 2019

Wangwu Reservoir is a multi-purpose reservoir that integrates urban water supply, irrigation, industrial water and landscape ecological water supply, and a multi-objective optimal scheduling model is established to explore the relationship between water supply loss and landscape loss caused by water shortage in Wangwu Reservoir. Based on the GANetXL program, the NSGA-II algorithm is applied to the optimal scheduling model of Wangwu Reservoir, and the Pareto optimal solution sets are obtained in the three different incoming water conditions of high flow year, normal flow year and low flow year. These optimal solution sets provide decision-making basis and specific program references for the optimal scheduling method of Wangwu Reservoir.
Study on Comprehensive Water Price of Multi-water Resources in Ningjin County
Authors: Sun Xiuxiu , Liu Haijiao , Fan Mingyuan , Ni Ludong , Wang Weiping
Published: September 2019

Ningjin County is located in northwest Shandong Province in the North China Plain. The water shortage can be solved if the South-to-North Water Transfer Project is completed, but the project water price is higher than the price of local groundwater and Yellow River water, so it is urgent to make the comprehensive water price of multi-water resources in this area. The water demand of non-agricultural water users in the planning year of 2020 and 2025 is forecasted based on water supply and consumption in current year of 2017, and two water supply schemes are set up respectively, four schemes totally considering the factors whether Yangtze River water will be obtained. The water prices of four schemes are calculated using weighted average model. The results show that when the transferring water replaces partial underground water in 2020, the comprehensive water prices of scheme 1 and scheme 2 are 3.21 yuan/m3 and 2.11 yuan/m3 respectively. When the transferring water replaces all groundwater in 2025, the comprehensive water prices of scheme 3 and scheme 4 are 2.92 yuan/m3 and 1.44 yuan/m3 respectively. The compensation mechanism of water price is discussed finally.
Preliminary Research and Application of MIKE SHE Model in Jialingjiang River Basin
Authors: Zhang Meng , Zhang Jing , Song Yongyu
Published: September 2019

Introduce the model structure, principle and characteristic of MIKE SHE hydrological model. Advances in research and application of MIKE SHE model are summarized in 3 aspects: applicability study of the model, basic process research of the model and further application research of the model. Probes into the modelling and application process of MIKE SHE model in Jialingjiang river basin. The development direction of MIKE SHE model in the future is analysed and forecasted, according to the research progress of MIKE SHE model in China.
Modelling and Design Analysis of Contract Payment Methods in Civil Engineering Projects
Authors: Ding Jiyong , Zhai Wujuan , Wang Zhuofu , Zhang Kun , Cai Juefang
Published: September 2019

Contract payment method in a civil engineering project, to a certain extent, determines the distribution of project risk and benefits. Up till now, several types of contract payment method have been formed. However, with the continuous development and innovation of project delivery system, new contract payment methods are required to match with project delivery methods. By comparing the existing classic payment methods, this paper analyzes the effects of variable contract payment methods on risk allocation. Based on a unified view, existing contract payment methods are expressed by mathematical models and compared with parameters, and then the way of contract payment method design is discussed. Finally, a case study was presented to illustrate the design of contract payment method for a specific project in Chinese context.
Study on the Coupling Vibration and Driving Comfort of the Railway and Highway Bi-purpose Bridge
Authors: Zhang Yuan , Wang Dongqi
Published: September 2019

In this paper, the influence of the track irregularity, speed and vehicle grouping on the dynamic respond and driving comfort of the bridge is studied. The results show that, the interaction between the automobile and the train can be effectively reduced by increasing the damping of the bridge structure; it’s the span and the train formation but not the speed and the track irregularity which effect the dynamic displacement of the bridge; the driving comfort is influenced a lot by the track irregularity. This study is of great significance to the driving comfort.