bluuebunny/crossref_metadata_2025 huggingface dataset:
All-optical structuring of laser-driven proton beam profiles
Authors: Obst-Huebl Lieselotte , Ziegler Tim , Brack Florian-Emanuel , Branco João , Bussmann Michael , Cowan Thomas E. , Curry Chandra B. , Fiuza Frederico , Garten Marco , Gauthier Maxence , Göde Sebastian , Glenzer Siegfried H. , Huebl Axel , Irman Arie , Kim Jongjin B. , Kluge Thomas , Kraft Stephan D. , Kroll Florian , Metzkes-Ng Josefine , Pausch Richard , Prencipe Irene , Rehwald Martin , Roedel Christian , Schlenvoigt Hans-Peter , Schramm Ulrich , Zeil Karl
Published: December 2018

Extreme field gradients intrinsic to relativistic laser-interactions with thin solid targets enable compact MeV proton accelerators with unique bunch characteristics. Yet, direct control of the proton beam profile is usually not possible. Here we present a readily applicable all-optical approach to imprint detailed spatial information from the driving laser pulse onto the proton bunch. In a series of experiments, counter-intuitively, the spatial profile of the energetic proton bunch was found to exhibit identical structures as the fraction of the laser pulse passing around a target of limited size. Such information transfer between the laser pulse and the naturally delayed proton bunch is attributed to the formation of quasi-static electric fields in the beam path by ionization of residual gas. Essentially acting as a programmable memory, these fields provide access to a higher level of proton beam manipulation.
Publisher Correction: Orthogonal Cas9-Cas9 chimeras provide a versatile platform for genome editing
Authors: Bolukbasi Mehmet Fatih , Liu Pengpeng , Luk Kevin , Kwok Samantha F. , Gupta Ankit , Amrani Nadia , Sontheimer Erik J. , Zhu Lihua Julie , Wolfe Scot A.
Published: December 2018

The original version of this Article contained errors in the author affiliations. Mehmet Fatih Bolukbasi was incorrectly associated with Bluebird Bio., Cambridge, MA, USA and Ankit Gupta was incorrectly associated with Exonics Therapeutics, Watertown, MA, USA. This has now been corrected in the HTML version of the Article. The PDF version of the Article was correct at the time of publication.
Broadband sound barriers with bianisotropic metasurfaces
Authors: Popa Bogdan-Ioan , Zhai Yuxin , Kwon Hyung-Suk
Published: December 2018

Noise is a long standing societal problem that has recently been linked to serious health consequences. Despite decades of research on noise mitigation techniques, existing methods have significant limitations including inability to silence broadband noise and shield large volumes. Here we show theoretically and experimentally that acoustic bianisotropic materials with non-zero strain to momentum coupling are remarkably effective sound barriers. They surpass state-of-the-art sound isolators in terms of attenuation, bandwidth, and shielded volume. We implement our barriers with very compact active meta-atoms that owe their small size to their local response to external sound. Moreover, our active approach is not constrained by feedback stabilization requirements, in stark contrast with all traditional active sound control systems. Consequently, bianisotropic sound barriers have the potential to revolutionize noise control technologies and provide much needed solutions to an increasingly important and difficult challenge.
Photodetection probability in quantum systems with arbitrarily strong light-matter interaction
Authors: Di Stefano Omar , Kockum Anton Frisk , Ridolfo Alessandro , Savasta Salvatore , Nori Franco
Published: December 2018

Cavity-QED systems have recently reached a regime where the light-matter interaction strength amounts to a non-negligible fraction of the resonance frequencies of the bare subsystems. In this regime, it is known that the usual normal-order correlation functions for the cavity-photon operators fail to describe both the rate and the statistics of emitted photons. Following Glauber’s original approach, we derive a simple and general quantum theory of photodetection, valid for arbitrary light-matter interaction strengths. Our derivation uses Fermi’s golden rule, together with an expansion of system operators in the eigenbasis of the interacting light-matter system, to arrive at the correct photodetection probabilities. We consider both narrow- and wide-band photodetectors. Our description is also valid for point-like detectors placed inside the optical cavity. As an application, we propose a gedanken experiment confirming the virtual nature of the bare excitations that enrich the ground state of the quantum Rabi model.
Air pollutant particulate matter 2.5 induces dry eye syndrome in mice
Authors: Tan Gang , Li Juan , Yang Qichen , Wu Anhua , Qu Dong-Yi , Wang Yahong , Ye Lei , Bao Jing , Shao Yi
Published: December 2018

In this study, we explored the effects of particulate matter 2.5 (PM2.5) eye drops on the ocular surface structure and tear function in mice and established a novel animal model for dry eye research. We found that, following treatment with PM2.5, the tear volume and, the tear film break-up time showed statistical differences at each time point (P < 0.05). The FL score of the PM2.5-treated group was higher than that of others (P < 0.05). The average number of corneal epithelial layer cells in groups A and B was significantly lower than that in group C (P < 0.05). Scanning electron microscopy and transmission electron microscopy revealed that the number of corneal epithelial microvilli and corneal desmosomes was drastically reduced in group C. PM2.5 induced apoptosis in the corneal superficial and basal epithelium and led to abnormal differentiation and proliferation of the ocular surface with higher expression levels of Ki67 and a reduced number of goblet cells in the conjunctival fornix in group C. PM2.5 significantly increased the levels of TNF-α, NF-κB p65 (phospho S536), and NF-κB in the cornea. Thus, the topical administration of PM2.5 in mice induces ocular surface changes that are similar to those of dry eye in humans, representing a novel model of dry eye.
Active Acupoints Differ from Inactive Acupoints in Modulating Key Plasmatic Metabolites of Hypertension: A Targeted Metabolomics Study
Authors: Yang Mingxiao , Yu Zheng , Chen Xiaomin , Guo Zhenyu , Deng Shufang , Chen Lin , Wu Qiaofeng , Liang Fanrong
Published: December 2018

The effect of active acupoints versus inactive acupoints in treating hypertension is not well documented. Metabolic phenotypes, depicted by metabolomics analysis, reflect the influence of external exposures, nutrition, and lifestyle on the integrated system of the human body. Therefore, we utilized high-performance liquid chromatography tandem mass spectrometry to compare the targeted metabolic phenotype changes induced by two different acupoint treatments. The clinical outcomes show that active acupoint treatment significantly lowers 24-hour systolic blood pressure but not diastolic blood pressure, as compared with inactive acupoint treatment. Furthermore, distinctive changes are observed between the metabolomics data of the two groups. Multivariate analysis shows that only in the active acupoint treatment group can the follow-up plasma be clearly separated from the baseline plasma. Moreover, the follow-up plasma of these two groups can be clearly separated, indicating two different post-treatment metabolic phenotypes. Three metabolites, sucrose, cellobiose, and hypoxanthine, are shown to be the most important features of active acupoint treatment. This study demonstrates that metabolomic analysis is a potential tool that can be used to efficiently differentiate the effect of active acupoints from inactive acupoints in treating hypertension. Possible mechanisms are the alternation of hypothalamic microinflammation and the restoration of host-gut microbiota interactions induced by acupuncture.
Age-Dependent Protection of Insulin Secretion in Diet Induced Obese Mice
Authors: De Leon Elizabeth R. , Brinkman Jacqueline A. , Fenske Rachel J. , Gregg Trillian , Schmidt Brian A. , Sherman Dawn S. , Cummings Nicole E. , Peter Darby C. , Kimple Michelle E. , Lamming Dudley W. , Merrins Matthew J.
Published: December 2018

Type 2 diabetes is an age-and-obesity associated disease driven by impairments in glucose homeostasis that ultimately result in defective insulin secretion from pancreatic β-cells. To deconvolve the effects of age and obesity in an experimental model of prediabetes, we fed young and aged mice either chow or a short-term high-fat/high-sucrose Western diet (WD) and examined how weight, glucose tolerance, and β-cell function were affected. Although WD induced a similar degree of weight gain in young and aged mice, a high degree of heterogeneity was found exclusively in aged mice. Weight gain in WD-fed aged mice was well-correlated with glucose intolerance, fasting insulin, and in vivo glucose-stimulated insulin secretion, relationships that were not observed in young animals. Although β-cell mass expansion in the WD-fed aged mice was only three-quarters of that observed in young mice, the islets from aged mice were resistant to the sharp WD-induced decline in ex vivo insulin secretion observed in young mice. Our findings demonstrate that age is associated with the protection of islet function in diet-induced obese mice, and furthermore, that WD challenge exposes variability in the resilience of the insulin secretory pathway in aged mice.
Green synthesis of fluorescent carbon dots as an effective fluorescence probe for morin detection
Authors: Liu Lizhen , Mi Zhi , Hu Qin , Li Caiqing , Li Xiaohua , Feng Feng
Published: December 2018

A green microwave method using glycine and urea as precursors was developed to synthesize carbon dots (CDs). The CDs can be used as an effective fluorescence probe with high selectivity and sensitivity for the detection of morin based on the fluorescence quenching of CDs.
Correction: Unexpected surface interactions between fluorocarbons and hybrid organic inorganic perovskites evidenced by PM-IRRAS and their application towards tuning the surface potential
Authors: Sadhu Subha , Aqueche Kyler , Buffeteau Thierry , Vincent Jean-Marc , Hirsch Lionel , Bassani Dario M.
Published: December 2018

Correction for ‘Unexpected surface interactions between fluorocarbons and hybrid organic inorganic perovskites evidenced by PM-IRRAS and their application towards tuning the surface potential' by Subha Sadhu et al., Mater. Horiz., 2019, DOI: 10.1039/c8mh01119b.
Morphology-tunable WMoO nanowire catalysts for the extremely efficient elimination of tetracycline: kinetics, mechanisms and intermediates
Authors: Hu Yi , Chen Ke , Li Yu-Lian , He Jun-Yong , Zhang Kai-Sheng , Liu Tao , Xu Wei , Huang Xing-Jiu , Kong Ling-Tao , Liu Jin-Huai
Published: December 2018

Ultrathin WMoO nanowires were controllably prepared for the highly efficient degradation of tetracycline under neutral conditions.
Characterizing percolative materials by straining
Authors: Yao Heming , Hempel Marek , Hsieh Ya-Ping , Kong Jing , Hofmann Mario
Published: December 2018

Carrier transport in a wide range of nanomaterial assemblies proceeds by percolation through discontinuous networks of constituents.
Rapid fabrication of porous silicon/carbon microtube composites as anode materials for lithium-ion batteries
Authors: Wang Shuxian , Huang Chunlai , Wang Lei , Sun Wei , Yang Deren
Published: December 2018

We added additives to the acid etching solution and prepared the silicon/carbon microtubes composites using a simple and fast method.
Double-ratiometric fluorescence imaging of H2Se and O2˙− under hypoxia for exploring Na2SeO3-induced HepG2 cells' apoptosis
Authors: Gao Xiaonan , Guo Wenfei , Ge Lihong , Kong Fanpeng , Xu Kehua , Tang Bo
Published: December 2018

Sodium selenite (Na2SeO3), as an anti-tumor drug for inducing tumor cells' apoptosis, has been widely studied under normoxic conditions and has been shown to exhibit oxidative stress process-induced apoptosis.
Phenol–TiO2 complex photocatalysis: visible light-driven selective oxidation of amines into imines in air
Authors: Shi Ji-Long , Hao Huimin , Lang Xianjun
Published: December 2018

A new photocatalytic protocol utilizing surface complexation of phenol with TiO2 for the selective oxidation of amines into imines in air was presented.
Cobalt single-atoms anchored on porphyrinic triazine-based frameworks as bifunctional electrocatalysts for oxygen reduction and hydrogen evolution reactions
Authors: Yi Jun-Dong , Xu Rui , Chai Guo-Liang , Zhang Teng , Zang Ketao , Nan Bing , Lin Hua , Liang Yu-Lin , Lv Jiangquan , Luo Jun , Si Rui , Huang Yuan-Biao , Cao Rong
Published: December 2018

Cobalt single atoms anchored on porphyrinic triazine frameworks exhibit high activity in ORR and HER.
Growth of BiVO4 nanoparticles on a WO3 porous scaffold: improved water-splitting by high band-edge light harvesting
Authors: Kim Kiwon , Nam Seong Kyung , Park Jong Hyeok , Moon Jun Hyuk
Published: December 2018

We demonstrate a heterojunction photoanode of WO3 coated with BiVO4 nanoparticles with high band-edge light absorption.
A strongly coupled 3D ternary Fe2O3@Ni2P/Ni(PO3)2 hybrid for enhanced electrocatalytic oxygen evolution at ultra-high current densities
Authors: Cheng Xiaodi , Pan Zhiyan , Lei Chaojun , Jin Yangjun , Yang Bin , Li Zhongjian , Zhang Xingwang , Lei Lecheng , Yuan Chris , Hou Yang
Published: December 2018

A ternary Fe2O3@Ni2P/Ni(PO3)2 hybrid with strong coupling and synergistic effects was developed for highly active OER at ultra-high current densities.
Synthesis of the anionic hydroxypropyl-β-cyclodextrin:poly(decamethylenephosphate) polyrotaxane and evaluation of its cholesterol efflux potential in Niemann–Pick C1 cells
Authors: Egele Kerstin , Samaddar Shayak , Schneider Nina , Thompson David , Wenz Gerhard
Published: December 2018

We describe for the first time the homogenous assembly of a water soluble polyrotaxane from HP-β-CD and an anionic posphodiester. The resulting polyrotaxane displays cholesterol normalization activity in NPC cells.
Aging-induced light-soaking effects and open-circuit voltage hysteretic behavior of inverted perovskite solar cells incorporating a hole transport metal halide layer via morphology-dependent inflow of iodide ions
Authors: Hong Jungyun , Kim Hyebin , Hwang Inchan
Published: December 2018

Aging-induced light soaking and hysteretic behavior of methylammonium lead trihalide perovskite solar cells can be seen dependent on the morphology of copper iodide (CuI) utilized as a hole-transport layer.
Flexible nanophosphor films doped with Mie resonators for enhanced out-coupling of the emission
Authors: Miranda-Muñoz José M. , Geng Dongling , Calvo Mauricio E. , Lozano Gabriel , Míguez Hernán
Published: December 2018

Herein, we present a general method to prepare self-standing flexible photoluminescent coatings of controlled opacity for integration into light-emitting diodes (LEDs) employing cost-effective solution-processing methods.
Intelligent vehicle safety system based on BeiDou satellite navigation system
Authors: Wu Yun‐Hua , Zheng Mo‐Hong , He Wei , Chen Zhi‐Ming , Hua Bing
Published: December 2018

With the popularisation of cars, traffic accidents occur every day. To improve driving safety and avoid accidents, an intelligent vehicle safety system based on BeiDou Satellite Navigation System is proposed. The system performs real‐time monitoring of the status of surrounding vehicles. Therefore, potential accidents can be predicted and first aid can be carried out immediately after accident. Warning can also be sent to the neighbours through the Vehicle Ad‐hoc Network. The intelligent system has four major functions: (i) Vehicle road imaging, which forms a real‐time road map through monitoring the real‐time status of the vehicle combined with the traffic conditions and prompts the dangerous road section. (ii) Dangerous driving behaviour rating assessment, which evaluates the behaviours of other vehicle drivers by expert system and reminds the driver to pay attention to such vehicles. (iii) Car accident early warning, providing a timely warning of the risk of car accident. (iv) Car accident alarm, which pushes message to the nearby vehicles once the accident occurred, and notifies the police and first aid unit through BeiDou short message if necessary. With the implementation of the system, most serious accidents can be avoided, and it can effectively improve traffic safety and reduce casualties and property losses.
Integrated resource expansion planning of wind integrated power systems considering demand response programmes
Authors: Hamidpour Hamidreza , Aghaei Jamshid , Dehghan Shahab , Pirouzi Sasan , Niknam Taher
Published: December 2018

Here, an optimisation framework is proposed for integrated resource expansion planning (IREP) including conventional generation units, wind generation units, and transmission lines while taking into account the role of demand response program (DRP) aggregators. This problem is a bi‐level optimisation problem. In the upper‐level problem, the objective function is to maximise the profit for each resource, that is, the generation company (GENCO), wind generation company (WINDCO), and transmission company (TRANSCO) as well as the DRP aggregator. Also, the lower‐level problem considers a market model with the participation of private GENCOs, WINDCOs, TRANSCOs, and DRP aggregators. The lower‐level problem minimises energy cost subject to AC power flow (PF) equations, power network limitations, pollution constraint, GENCO, WINDCO, TRANSCO constraints, and technical limitations of DRPs. Here, the lower‐level problem is non‐linear and non‐convex. Accordingly, to facilitate the solution of the proposed bi‐level optimisation problem, a linear model is proposed. Then, the proposed bilevel optimisation problem is converted into an integrated single‐level one using the Karush‐Kuhn‐Tucker (KKT) conditions. Eventually, a mixed‐integer linear programming (MILP) model is proposed. The proposed method is applied to the IEEE 6‐bus and the IEEE 30‐bus test systems, and finally, the capabilities of the proposed scheme are evaluated.
Control scheme for multi‐terminal VSC‐based medium‐voltage DC distribution networks
Authors: Ji Yirun , Yuan Zhichang , Zhao Jianfeng , Zhao Yuming , Li Guoxiang , Li Yan
Published: December 2018

With the development and application of voltage source converter (VSC) high voltage direct current (HVDC) technology, DC distribution is gradually attracting the attention of researchers in recent years. However, many studies are still in the theoretical and exploratory stages. Compared with DC transmission networks, medium‐voltage DC (MVDC) distribution networks are more sophisticated with respect to the complex operation modes, high penetration of renewable energy resource, and use of diverse power electronic devices. Therefore, master–slave control strategy which has been widely used in HVDC transmission projects may not be the first choice for DC distribution networks. In this study, a three‐terminal DC distribution dynamic simulation platform is initially established and droop control strategy is adopted due to its flexible scalability. Secondly, plug and play solutions for key equipment such as VSCs and DC solid‐state transformers are proposed. Thirdly, the response characteristics of a droop control system under high renewable energy resource penetration and frequent transition of operation mode are studied. Fourthly, the system fault isolation and recovery strategy under DC pole‐to‐pole fault is proposed. Finally, the whole control scheme is validated through experiments using the dynamic simulation platform. In the future, this proposed scheme can be used in the control of VSC‐based MVDC distribution networks.
Photocatalytic performance of rod‐shaped copper oxides prepared by spin coating
Authors: Koohestani Hassan
Published: December 2018

Copper oxides (CuO and Cu2 O), having narrow bandgap and a variety of chemophysical properties, are attractive in many fields such as solar cells, energy conversion, optoelectronic devices, and catalyst. In this work, these copper oxides are synthesised via co‐precipitation method and spin coating and annealed in various temperatures. Then, samples are characterised by X‐ray powder diffraction, scanning electron microscopy (SEM) and ultraviolet–visible light absorption spectra. From the SEM images of sample annealed at 450°C, the diameter and lengths range of the rod‐shaped particles were 30–70 and 200–300 nm, respectively. Finally, to investigate the photocatalytic activity of oxides, methyl orange (MeO) degradation by copper oxides under UV irradiation was studied. Pure CuO with bandgap energy 1.37 eV and specific surface areas 91.3 m2/g had a greater efficiency of MeO degradation value 87.8%.
Lack of high-mass pre-stellar cores in the starless MDCs of NGC 6334
Authors: Louvet F. , Neupane S. , Garay G. , Russeil D. , Zavagno A. , Guzman A. , Gomez L. , Bronfman L. , Nony T.
Published: December 2018

Context. The formation of high-mass stars remains unknown in many aspects. There are two competing families of models to explain the formation of high-mass stars. On the one hand, quasi-static models predict the existence of high-mass pre-stellar cores sustained by a high degree of turbulence. On the other hand, competitive accretion models predict that high-mass proto-stellar cores evolve from low or intermediate mass proto-stellar cores in dynamic environments.

Aims. The aim of the present work is to bring observational constraints at the scale of high-mass cores (~0.03 pc).

Methods. We targeted with ALMA and MOPRA a sample of nine starless massive dense cores (MDCs) discovered in a recent Herschel/HOBYS study. Their mass and size (~110 M⊙ and r = 0.1 pc, respectively) are similar to the initial conditions used in the quasi-static family of models explaining for the formation of high-mass stars. We present ALMA 1.4 mm continuum observations that resolve the Jeans length (λJeans ~ 0.03 pc) and that are sensitive to the Jeans mass (MJeans ~ 0.65 M⊙) in the nine starless MDCs, together with ALMA-12CO(2–1) emission line observations. We also present HCO+(1–0), H13CO+(1–0) and N2H+(1–0) molecular lines from the MOPRA telescope for eight of the nine MDCs.

Results. The nine starless MDCs have the mass reservoir to form high-mass stars according to the criteria by Baldeschi et al. (2017). Three of the starless MDCs are subvirialized with αvir ~ 0.35, and four MDCs show sign of collapse from their molecular emission lines. ALMA observations show very little fragmentation within the MDCs. Only two of the starless MDCs host compact continuum sources, whose fluxes correspond to <3 M⊙ fragments. Therefore, the mass reservoir of the MDCs has not yet been accreted onto compact objects, and most of the emission is filtered out by the interferometer.

Conclusions. These observations do not support the quasi-static models for high-mass star formation since no high-mass pre-stellar core is found in NGC 6334. The competitive accretion models, on the other hand, predict a level of fragmentation much higher than what we observe.
Water delivery in the inner solar nebula
Authors: D’Angelo M. , Cazaux S. , Kamp I. , Thi W.-F. , Woitke P.
Published: December 2018

Context.Endogenous or exogenous, dry or wet, various scenarios have been depicted for the origin of water on the rocky bodies in our solar system. Hydrated silicates found in meteorites and in interplanetary dust particles, together with observations of abundant water reservoirs in the habitable zone of protoplanetary disks, are evidence that support aqueous alteration of silicate dust grains by water vapor condensation in a nebular setting.

Aims.We investigate the thermodynamics (temperature and pressure dependencies) and kinetics (adsorption rates and energies, surface diffusion and cluster formation) of water adsorption on surfaces of forsterite grains, constraining the location in the solar nebula where aqueous alteration of silicates by water vapor adsorption can occur efficiently and leads to the formation of phyllosilicates. We analyze the astrophysical conditions favorable for such hydration mechanism and the implications for water on solid bodies.

Methods.The protoplanetary disk model (ProDiMo) code is tuned to simulate the thermochemical disk structure of the early solar nebula at three evolutionary stages. Pressure, temperature, and water vapor abundance within 1 au of the protosun were extracted and used as input for a Monte Carlo code to model water associative adsorption using adsorption energies that resemble the forsterite [1 0 0] crystal lattice.

Results.Hydration of forsterite surfaces by water vapor adsorption could have occurred within the nebula lifetime already at a density of 108cm−3, with increasing surface coverage for higher water vapor densities. Full surface coverage is attained for temperatures lower than 500 K, while for hotter grain surfaces water cluster formation plays a crucial role. Between 0.5 and 10 Earth oceans can arise from the agglomeration of hydrated 0.1μm grains into an Earth-sized planet. However, if grain growth occurs dry and water vapor processes the grains afterward, this value can decrease by two orders of magnitude.

Conclusions.This work shows that water cluster formation enhances the water surface coverage and enables a stable water layer to form at high temperature and low water vapor density conditions. Finally, surface diffusion of physisorbed water molecules shortens the timescale for reaching steady state, enabling phyllosilicate formation within the solar nebula timescale.
Numerical simulation on a heavy storm for 26th Jul of Yellow River
Authors: Liu Ke , Lei Xiaohui , Liu Jifeng , Yang Mingxiang
Published: December 2018

Aiming to investigate the weather characteristics and mesoscale system in the heavy rainstorm process on Jul 26, 2017 of Yellow River, the conventional observations and mesoscale numerical model (WRF) and its assimilation system 3DVAR was utilized to simulate the major precipitation period. The difference between the results of model with assimilation observation date of meteorological observation stations and without assimilation were also discussed. the results indicates that upper at 500hPa and shear line at 850hPa form the forward-titling trough which provides favorable instability conditions for generation of rainstorm. stability of subtropical high is beneficial to the water flux transporting to main precipitation zone. the wind shear at 850hPa and surface cyclone are the mesoscale systems. By comparing the simulations with and without assimilation, the result showed that the simulation with assimilation improved obviously the location of heavy rain and spatial distribution of different levels of precipitation. Of which the region with precipitation below 10mm simulated by experiment with assimilation was greatly improved. At the factors of atmospheric circulation field, the intensities of water vapor transportation and surface cyclone have strengthened after assimilation, thus can support more favorable conditions for development of convection's system. its implied that simulations after assimilation improve the spatial structure of initial field, and have an essential effect on simulating mesoscale convective system's structure.
Study on Selection of Pressure Regulating Valve for Hydropower Station with Both Surge Tank and Pressure Regulating Valve
Authors: Zhou Tianchi , Li Gaohui , Chen Yimin
Published: December 2018

The transient process in the hydropower station with both surge tank and pressure regulating valve is quite complicated and also critical to operation safety. According to the pressure regulating valve working principle, the influence of the valve diameter on the unit speed and spiral case pressure was analyzed theoretically. Mathematical models of the surge tank and pressure regulating valve in the hydropower station were established based on the characteristic method. In a practical engineering, numerical simulation of large fluctuation and hydraulic disturbance transient process are conducted, verifying the correctness of the theoretical analysis. Based on the calculation results, three principles for selecting the valve diameter are concluded: first, making sure the unit speed meet the regulating guarantee requirements when guide vanes fast close; second, the maximum spiral case pressure of two times should be approximate to each other by controlling the superposition of surge wave and water hammer; third, the maximum flow of the valve should be as close to the rated flow of the turbine as possible. The principles are helpful for selecting the valve diameter in similar hydropower station.
Joint Dispatching of the Reservoirs in the Yuanshui Basin Based on Regime Forecast System and Intelligent Meteorology Forecast
Authors: Mo Yujun , Wu Xin
Published: December 2018

This paper briefly introduces the construction of Wuling's automatic monitoring and forecast system of flood regimen, intelligent meteorological system and cascade reservoir dispatching system, and summarizes the joint power generation dispatching and flood control dispatching of cascade reservoirs in Yuanshui basin since 2010. Taking the Yuanshui basin flood in 2017 as an example, the application of joint flood control dispatching for reservoirs is analyzed. The relevant research results of this paper can be used as reference for production technology management personnel.
The optimal equilibrium operation between power generation and ecology of Qingjiang cascade hydropower stations
Authors: Li Yinghai , Lin Wei , Guo Jiali , Xia Qingqing , Li Wang
Published: December 2018

Ecological operation of cascade hydropower stations is one of the most important methods for the ecological restoration of a river system. In order to balance the benefits between power generation and ecology of Qingjiang cascade hydropower station, an optimal equilibrium operation method is proposed in this paper. Firstly, the range of ecological flow of the Qingjiang cascade is calculated by using ten-day frequency calculation method. Secondly, an optimal equilibrium operation model by considering the balance between power generation and ecology is established. And then, in order to solve this complex model, a particle swarm optimization based model solution method is proposed, and the evaluation index system of operation schemes is established. Finally, through operation calculation in 2008-2010 years, the results show that compared with the operation scheme considering only power generation benefit, the optimal equilibrium operation scheme increases the runoff ecological dispersion coefficient by 6.90%，reduces the cascade ecological overflow by 7.739 billion m3and the cascade ecological water shortage by 130 million m3, while the cascade power generation decreases slightly by 1.83%. This study provides an effective scientific method for the optimal operation of Qingjiang cascade under the background of Yangtze River protection.
Application of Synthetic Unit Hydrograph on HEC-HMS Model for Flood Forecasting
Authors: Haibo Ma , Xin Dong , Wenjuan Chang
Published: December 2018

The surface runoff model of the HEC-HMS hydrological modeling system is mainly simulated through the unit line method. The simulated results usually had big errors because of the flood with different net rainfall magnitude using the same set of unit lines. In this paper, the Huan River Basin was selected as the study area for the flood forecasting using HEC-HMS model. In the process of the HEC-HMS hydrological model construction, the ArcGIS software was used to extract the watershed information according to the river DEM data. The net rainfall was calculated through the initial constant rate loss model. The surface runoff of the basin was calculated by the Snyder unit line model, and the basis was calculated by the exponential decay model. The river flow convergence was calculated by the Muskingum method. Based on the rainfall runoff data of 17 floods, three sets of Snyder unit lines were calculated according to the net rainfall intensity, and then three large, medium and small floods were employed to verify the flow process of the exit section of the basin. The model was calibrated and verified using historical observed data. The results showed that: The determination coefficients and coefficients of agreement for all the flood events were above 0.92, and the relative errors in peak discharges were all within the acceptable range, which belongs to A-Level forecast. The simulation accuracy of the model in the Huan River basin can be enhanced by synthesizing the Snyder unit line in the HEC-HMS model according to the net rain intensity.
The Long-term Projection of Surface Runoff in the Regions above Danjiangkou in Hanjiang River Basin based on Water-energy Balance
Authors: Yin Jun , Yuan Zhe , Wang Run
Published: December 2018

The projection of surface runoff in the context of climate change is important to the rational utilization and distribution of water resources. This study did a case study in regions above Danjiangkou in Hanjiang River Basin. A basin scale hydrological model was built based on macroscale processes of surface runoff and water-energy balance. This model can describe the quantity relationship among climatic factors, underlying surface and surface runoff. Driven by hypothetical climatic scenarios and climate change dataset coming from CMIP5, the climate change impacts on surface runoff in the regions above Danjiangkou in Hanjiang River Basin can be addressed. The results showed that: (1) Compared with other distributed hydrological models, the hydrological model in this study has fewer parameters and simpler calculation methods. The model was good at simulating annual surface runoff. (2) The surface runoff was less sensitivity to climate change in the regions above Danjiangkou in Hanjiang River Basin. A 1°C increase in temperature might results in a surface runoff decrease of 2~5% and a 10% precipitation increase might result in a streamflow increase of 14~17%. (3) The temperature across the Fu River Basin were projected to increase by 1.4~2.3°C in 1961 to 1990 compared with that in 1961 to 1990. But the uncertainty existed among the projection results of precipitation. The surface runoff was excepted to decrease by 1.3~23.9% without considering the climate change projected by NorESM1-M and MIROC-ESM-CHEM, which was much different from other GCMs.
Construction and Application of Snow-melting Runoff Model Based on MODIS Satellite Data
Authors: Chen Jian , Shu Kai , Wang Jianping , Li Chunhong , Wang Feng
Published: December 2018

It is very complicated to accurately describe the process of watershed runoff yield and concentration, which is comprehensive influenced by snow covering, temperature, precipitation, the wetland areas and other factors in the basin of Kaidu River upstream of Chahanwusu Reservoir. It is that real-time updating MODIS satellite snow cover products MOD10A2 and 30 meters by 30 meters of DEM data are applied to calculate elevation~ basin area ~ snow covering area curve, virtual free reservoir is put forward to simulate the wetlands concentration of upstream Bayinbuluke and sahentuohai hydrological gauge stations and mixed melting snow and runoff yield under saturated storage concentration model is constructed in this article. The model behaved good to simulate the Inflow process of Chahanwusu Reservoir, and the relative error between simulated and measured processes reached 83.79%, the deterministic coefficient reaches about 0.8, which is better supporting Chahanwusu Reservoir’s operation scheduling and dispatch decision.
Analysis on the Return Period of “7.26” Rainstorm and Flood in 2017 in the Wudinghe Basin
Authors: Jin Shuang-yan , Gao Wen-yong , Luo Si-wu , Gao Ya-jun
Published: December 2018

The return period of "7.26" rainstorm flood in 2017 in Wudinghe basin is analyzed by the method of P-III distribution. The Lijiahe and Dingjiagou stations with long rainfall observation data in the rainstorm area are selected, and the frequency curve of the annual maximum 24 hours rainfall are established, and the recurrence period of rainfall stations in rainstorm area are estimated according to the parameters determined by the curve fitting method. The frequency curve of the annual maximum peak discharge of Baijiachuan hydrological stations and so on are established, and the return period are analyzed in combination with the historical survey floods. The results show that the return period of Zhaojiabian of heavy rainfall center is about 100 years, and which of the other stations over than 200mm in Wudinghe basin is about 30~90 years; while the return period of the peak discharge of Baijiachuan and Suide hydrological station is about 30 and 20 years respectively.
A rapid solution adjustment strategy in solving Long-term scheduling of large cascade hydropower stations
Authors: Wang Chao , Ji Liang , Song Peibing , Hu Xin , Sun Jiahui
Published: December 2018

Due to the great potential of large cascade hydropower stations on power generation, long-term scheduling of large cascade hydropower stations (LSLCHS) plays an important role in electrical power system. As more and more concentrations focused on the optimal operation of large cascade hydropower stations, the LSLCHS has been taken into a multi-dimensional, non-convex and non-linear optimization problem due to its complicated hydraulic connection relationships and varieties of complex constraints with considering its power generation, shipping and ecological characteristics. In order to solve this problem, a strategy of solution rapid adjustment regarding the principle of monotone principle is proposed accordingly. The simulation results show that the proposed method is an efficient for solving joint optimization dispatch model of cascade hydropower stations with fast convergent rate, strong robustness.
Variation characteristics and influencing factors of free water evaporation in recent 58 years in Tai’an area
Authors: Yan Kun , Yang Min-Zhi , Gao Shang , Li Jie-Yu
Published: December 2018

The mutation test and trend analysis of free water evaporation in Tai’an from 1956 to 2013 were carried out with Pettitt detection method, Mann-Kendall method and linear tendency estimation method. The results indicate that: (1) the free water evaporation in Tai’an was distributed unevenly within the year, and the maximum appeared in June, accounting for 14.5% of the whole year; (2) in the last 58 years, the free water evaporation in Tai’an changed significantly in 1985. The evaporation decreased obviously before the change, then fluctuated around the mean value, and gradually became stable; (3) by means of correlation analysis and partial differential decomposition, it was found that free water evaporation in Tai’an before 1985 was positively correlated with air temperature, solar radiation and wind speed, and negatively correlated with actual water vapor pressure. The significant decrease in solar radiation and wind speed are the main reasons for the significant decline in annual evaporation; (4) after 1985, the air temperature played a dominant role, and the rise of air temperature offset the negative influence of decline of wind speed and solar radiation on the free water evaporation.
Construction of water supply and drainage engineering
Authors: Zhang Haiying
Published: December 2018

Construction of water supply and drainage engineering is one of the main special courses offered to students whose major is Water Supply and Drainage. Through learning of this course, the students should understand earth and rock works, water drainage in the process of construction, pipe slotting construction, non-pipe slotting construction, underwater construction, energy-saving and noise reduction in the design of water supply and drainage system, mechanical equipment installation, water structure, and maintenance and maintenance. Urban supply system and drainage system are major strong guarantee of development of cities and one of an important infrastructure projects. Therefore, it is required to culture graduate in the field of water supply and drainage engineering. The paper offers a construction plan for the course in the following aspects: revision of teaching content, improvement of teaching method, arrangement of test database and exercise database and ways to increasing teaching effect of this course, and result of construction.
Optimization of Drainage Schemes for the Dike Strengthening by Warping Construction Project in the Qinhe River under Restricted Drainage Condition
Authors: Yang Hao-Ming , Zhang Min , Dong Cheng-Hui
Published: December 2018

Dike strengthening by warping construction is one of the main construction modes for the standardized dike construction of mainstream and tributaries in the lower reaches of the Yellow River, and whether the drainage in the dike strengthening by warping construction is smooth is closely related to the safety of dike project. Restricted by topographic conditions and construction conditions, existing drainage schemes are not applicable to the Qinhe River (the Yellow River’s largest tributary) Flood Prevention Project Wuzhi Section, which is next to farm cottage. Therefore, in this paper a field test was carried out using three drainage schemes---“L” type PVC seepage drainage pipes through dike, “L” type perforated PVC seepage drainage pipes coated with geotextile and geotextile drainage grilles. The drainage velocity, silt retaining effect, water level in the silt area, dike body deformation and other key indicators were obtained through field monitoring, and the safety and stability of the dike strengthening by warping construction project were verified by numerical calculation. The field test results showed that the drainage effect of the “L” type perforated PVC seepage drainage pipes coated with geotextile and geotextile drainage grilles was obviously better than that of the “L” type PVC seepage drainage pipes through dike, but the geotextile drainage grilles had advantages in silt retaining effect, construction convenience, cost, and improvement. The field test results can provide a reference for the quick drainage design and construction of dike back deposited with silt of the dike strengthening by warping construction project in the Yellow River.
Diagnose Urban Drainage Network Problem Based on Internet of Things and Big Data
Authors: Miao Xiaobo , Lv Mou , Liang Fengchao , Jiao Chunjiao , Wang Luohua
Published: December 2018

Urban drainage pipe network is an important foundation project in urban construction. It has a vital impact on urban waterlogging prevention and water pollution. However, in the current practice, there are many hidden problems in the pipe network, and it is difficult to check the pipe network problem, which restricts the understanding of the drainage system problem to a certain extent. In order to solve the two technical problems of drainage network survey and data statistics, the monitoring technology based on Internet of things and big data is adopted in this study. Taking the sponge city pilot area of a coastal city in China as the research area, the monitoring scheme was established and the monitoring data were obtained. Based on more than 6 million monitoring data, the automatic analysis algorithm is applied to analyse the problems of mixed connection of rain and sewage and tidal backwater in the pipeline network. The results show that there are a total of 17 outlets in 160 outlets with problems of rain and sewage mixing. Among them, there are four outlets with regular domestic sewage entering the rainwater pipe network, 7 outlets with irregular sewage entering the rainwater pipe network, and 6 outlets where sewage is smuggled into the rainwater pipe network. In addition, there is a sea tidal backwater phenomenon at one of the coastal rainwater outfalls.
Analysis of Water Cycle in Weizhou Island of Beihai City, Guangxi Province, Part I: Theory and Model Parameter Identification
Authors: Zhang Shunfu , Liu Changjun , Li Chuanke , Long Sili , Zhou Jian , Zhang Qiyi
Published: December 2018

Groundwater is almost the unique source of water for Weizhou Island. Groundwater overexploitation has caused the groundwater level gradually dropping these years, causing many environmental problems such as seawater intrusion. On the basis of previous water resources survey and the understanding of the water cycle of Weizhou Island, the precipitation-runoff and variable-density groundwater flow analysis model in Weizhou Island was established. Model parameters were identified by historical rainfall and groundwater level data.
Optimization of water flushing in lowland urban river in Jiaxing, Zhejiang using dissolved oxygen as the indicator
Authors: Tan Peiying , Zhu David Z. , Zhang Yiping , Zhou Yongchao
Published: December 2018

River flushing has been considered as an effective tool for improving water quality in heavily polluted urban rivers. Dissolved oxygen (DO) as the evaluation index of water quality varied with time during and after water flushing. The time intervals between the flushing should be optimized such that the DO concentration remains above 2mg/L in the river. The duration between the flushing was found to be mainly correlated to the water temperature and the saturation level of dissolved oxygen. For the study river, when the temperature was below 15 ℃, there was an exponential relationship between the duration and saturation level of DO. For instance, the estimated duration was 157 hours or about 7 days for the subsequent flushing when the saturation level of DO was 90%. This duration was no more than 2 days when the temperature was above 15 ℃.
Prediction model of Populus simonii seedlings based on growth characteristics in China
Authors: Ge Huishuo , Zhang Xiaoyu
Published: December 2018

In this paper, we originally apply the BP neural network to predict the plant height of Populus simonii seedlings. Firstly, we explore correlation among the section length variables of Populus simonii seedlings in four growth periods by using principal component analysis and hierarchical clustering method, which obtain 5 principal components. In addition, we utilize Fuzzy C-Means Clustering (FCM) to classify the Populus simonii seedlings, and are obviously classified into two subpopulations. Furthermore, we utilize BP neural network to establish seedlings height growth model and aboveground biomass prediction model, respectively. Through numerical experiments, prediction accuracy of the seedling height growth models in four periods reaches about 84.89%. Meanwhile, the prediction accuracies of stem and leaf fresh weight and stem and leaf dry weight are 91.15% and 83.79%, respectively. This paper provides an effective method for studying phenotypic characteristics and predicting the height of Populus simonii seedlings, which supplies a reference for genome-wide association analysis.
The Design of Electrical Equipment Overheat Monitoring System on Electric Propulsion Ship Based on WSN
Authors: Ma Chuan , Li Diyang , Mao Hongyu
Published: December 2018

Wired electric equipment overheating monitoring system has some limitations in electric propulsion ships. This paper designs an electrical equipment overheat monitoring system based on Wireless Sensor Network (WSN) to monitor the overheat of electrical equipment. To verify the performance of the whole system, we design the hardware and the software of sensor nodes and coordinators. In order to extend the lifetime of sensor node effectively, the system adopts the dynamic sleep and controllable transmit power method. The results show that this system achieves the accurate measurement of electrical equipment temperature. At the same time, laboratory data tests shown that it can achieve the same accuracy as wired measurements. This paper provides a new solution for overheating monitoring of marine electrical equipment.
5G Mobile Communication Development Trend and Several Key Technologies
Authors: Zheng Liping
Published: December 2018

The overall performance of 5G mobile communication network has made great progress compared with 4G network. In order to ensure the expected utility of 5G communication system in practical application, this paper will focus on the future development trend of this communication system and its research on key technologies involved in the application process to provide theoretical support to relevant practitioners.