bluuebunny/crossref_metadata_2025_split huggingface dataset:
Present status of HIRFL complex in Lanzhou
Authors: Yuan Y J , Gao D Q , Ma L Z , Mao L J , Mao R S , Meng J , Su Y W , Sun L T , Wang Y Y , Wu J X , Xu Z , Yang J C , Yang W Q , Yao Q G , Yin X J , Zhang B , Zhang W , Zhou Z Z , Zhao H W , Xiao G Q , Xia J W 
Published: February 2020

Abstract
Heavy Ion Research Facility in Lanzhou (HIRFL) is a cyclotron, synchrotron and storage ring accelerator complex, which accelerates ions of hydrogen to uranium from low to medium energy. Since the complete of HIRFL-CSR project in 2008, under the support from CAS, efforts have been put to improve the infrastructure for machine performance, including improvement of EMC environments, power distribution stations, PS stations, cooling water system, RF system of cyclotrons and adoption of EPICS control system, etc. New generation SC ECR source (SECRAL-II) with high performance is put into operation. Experiments of electron cooling with pulsed electron beam are performed for the first time. Stochastic cooling and laser cooling are realized in CSRe. The performance of RIBLL2 and CSRe are gradually improved. The isochronous mode of CSRe for precise atomic mass measurements is well studied and reaches state-of-art mass resolution of storage rings. The operation status and enhancement plan of HIRFL will be briefly reported in this paper.
Commissioning of China ADS demo Linac and baseline design of CiADS project
Authors: Liu Shuhui , Wang Zhijun , Chen Weilong , Dou Weiping , Jia Huan , Qin Yuanshuai , He Yuan , Zhao Hongwei 
Published: February 2020

Abstract
China Accelerator Driven Subcritical System (C-ADS) program was launched in China in 2011. In the first five-year phase, a 25 MeV demo linac has been successfully built to demonstrate the key technologies of the driven linac. Beam commissioning activities have been carried out to study the high-power beam physics. Followed by the previous phase, China Initiative Accelerator Driven Subcritical System (CiADS) is approved contain a superconducting proton linac with 500 MeV and 5 mA. In this paper, the commissioning results of the demo linac and the beam dynamics design of CiADS linac based on commissioning experiences are presented.
First acceleration of heavy ion beams with a superconducting continuous wave HIM/GSI CW-linac
Authors: Basten M. , Aulenbacher K. , Barth W. , Busch M. , Dziuba F. , Gettmann V. , Heilmann M. , Kürzeder T. , Lauber S. , Miski-Oglu M. , Podlech H. , Rubin A. , Schnase A. , Schwarz M. , Yaramyshev S. 
Published: February 2020

Abstract
In the future a new superconducting (sc) continuous wave (cw) high intensity heavy ion Linac should provide ion beams with a max. beam energy above the coulomb barrier for the Super Heavy Element (SHE) program at GSI Helmholtzzentrum für Schwerionenforschung. Key features of this new Linac are the acceleration of different ions from protons to uranium as well as a smooth energy variation from 3.5 to 7.3 MeV/u for design ions with a mass-to-charge ratio A/q = 6 and even above for lighter ions. As a first step a newly developed superconducting 15-gap Crossbar H-cavity (CH-cavity) operated at 217 MHz has been successfully tested with heavy ion beam up to the design beam energy of 1.85 MeV/u for the first time. The design energy gain of 3.5 MV within a length of less than 70 cm has been validated with heavy ion beams of up to 1.5 pμA. The measured beam parameters showed excellent beam quality, while a dedicated beam dynamics layout provides beam energy variation between 1.2 and 2.2 MeV/u. The beam commissioning is a milestone of the R&D work of Helmholtz Institute Mainz (HIM) and GSI in collaboration with Goethe University Frankfurt (GUF) and the first step towards a sc heavy ion cw-Linac with variable beam energy. The first tests under cryogenic conditions of the next two CH-cavities have already been started at GUF in a vertical cryostat. The results of the first successful heavy ion beam acceleration with a superconducting CH-cavity will be presented.
DESIGN AND BEAM COMMISSIONING OF THE LEAF-RFQ
Authors: Lu Liang , He Tao , Yang Lei , He Yuan , Zhao Hongwei , Xing Chaochao , Zhai Yuhan , Shi Longbo , Sun Liepeng , Li Jia , Xia Qianxu 
Published: February 2020

Abstract
An 81.25 MHz continuous wave (CW) radio frequency quadrupole (RFQ) accelerator has been designed and fabricated for the Low Energy Accelerator Facility (LEAF) by the Institute of Modern Physics (IMP) of the Chinese Academy of Science (CAS). The operation frequency is 81.25 MHz and the inter-vane voltage is a constant of 70 kV. It took about 44 hours continuous conditioning to reach RF power of 75 kW which is 1.1 time of the maximum designed value, and the successful CW acceleration of 150 eµA He+ beam to the designed energy of 0.5 MeV/u was already done. The results of the low power test, the RF conditioning and the beam acceleration will be reported in this paper.
Cryogenic test of the FRIB superconducting magnets at IMP
Authors: Yang Wenjie , Wu Beimin , Ni Dongshen , Wu Wei , Mei Enming , Ma Lizhen 
Published: February 2020

Abstract
The superconducting magnets of the Facility of Rare Isotope Beams (FRIB) are used to focus and steer the heavy ion beams of the driver linac. All the magnets are designed as a solenoid with bucking coils to suppress the stray field, and all the magnets have superconducting dipole correctors to steer both horizontal and vertical field. Two types of magnets have been manufactured in China, and some of them have been tested at Institute of Modern Physic (IMP). This paper describes the test system and magnetic axis measurement method. We also present a summary of the measurement process and test results of the magnetic performance for the magnets.
Multi-physics analysis and experiment of a CW four-rod RFQ
Authors: Li Z S , Xia J W , Yuan Y J , Yang J C , He Y , Yang Y Q , Xu Z , Cong Y , Meng J , Jing L , Du H , Wang Z J , Zhang Y , Wang H N , Li X N , Wang K D , Xie W J , Wei Y , Xie H M , Xu X W , Shen G D , Kong Q Y , Yin X J , Wu J X , Lu Y R , Zhu K 
Published: February 2020

Abstract
The new injector SSC-LINAC is under design and construction to improve the efficiency and intensity of beams for the Separated-Sector Cyclotron (SSC). This will be accomplished with a normal conducting radio-frequency quadrupole (RFQ) accelerator. To match with the SSC, the RFQ must be operated on Continuous Wave (CW) mode with a frequency of 53.667 MHz. A four-rod structure was adopted for small dimensions of the cavity. While, it was a huge challenge on CW mode. A multi-physics theoretical analysis, including RF, thermal, structural and frequency shift coupling analysis, have been completed in response to the safe and stable operation of the RFQ. The experimental measurement of frequency shift has been also completed, which is consistent with the simulation. In this paper, the results of theoretical analysis and experiment are reported in detail.
Nb Sputtered 325 MHz QWR Cavities for CIADS
Authors: Pan F. , Tan T. , Xiong P. , Guo H. , Zhang C. , Jiang T. , He Y. , Li Z. , Wang H. 
Published: February 2020

Abstract
The possibility for adopting niobium thin film coated copper (Nb/Cu) quarter wave resonators (QWRs) in the low energy section of CiADS project[1] is being evaluated. Comparing with bulk niobium cavities, the Nb/Cu cavities feature a much better thermal and mechanical stability at 4.5 K. Two 325 MHz Nb/Cu QWR cavities have been fabricated at IMP, to demonstrate whether the niobium coated copper cavity technique can meet the requirements of CiADS. The cavity is coated with biased DC diode sputtering technique. This paper covers resulting film characters, vertical tests with the evolution of the sputtering process, and improvements to mitigate issues we met.
Traces of marine activity in the history of medieval Vologda
Authors: Adamenko O N , Yashina O V , Bashnin N V 
Published: February 2020

Abstract
Paleozoological study of archaeological findings from the excavations of Vologda settlement (12th–15th centuries) revealed information about trade and trade links between Vologda and the Arctic region. The existence of such links in the Middle Ages and the Modern Age is also confirmed by museum collections and written sources that contain information about the participation of residents Vologda in long-distance marine expeditions to the Arctic region.
Survival of indicator species of the mammoth fauna large mammals in the Holocene of Yakutia (East Siberia, Russia)
Authors: Boeskorov G G 
Published: February 2020

Abstract
Global climate change at the end of the Pleistocene led to extinction across the huge territories of the Northern Hemisphere of indicator species of large mammals of the mammoth fauna. Undoubtedly, in some more densely populated regions, the mammoth fauna underwent pressure from Upper Paleolithic humans hunting activity. Previously it was thought that the megafauna of the “Mammoth complex” had become extinct in the territory of Yakutia by the beginning of the Holocene. However, the latest data indicate that extinction of the mammoth fauna was significantly delayed in the north of Eastern Siberia. Radiocarbon data show that wild horses inhabited the north of Yakutia during 5300–2200 cal yr BP. Musk oxen lived here about 3400 – 2600 cal yr BP. Some bison remains from Yakutia belong to the early Holocene. The following circumstances could have facilitated the survival of representatives of the mammoth fauna in Yakutia. The cool, dry climate in this region is favorable to steppe associations, the habitats of these mammals. The small number of Stone Age hunting tribes in the northern part of Yakutia was probably another factor that contributed to the survival of some mammoth fauna representatives.
Effect of insolation variations on vegetations of the Eurasian subarctic during the Holocene
Authors: Kuznetsov E , Galimov A , Shalaumova J , Borodin A 
Published: February 2020

Abstract
Variation of the insolation is one of the global factors which determine the Earth’s climate. Multi-periodic variations of the insolation determine the cyclicity of the Earth’s climate. The aim of the investigation is the estimation of the insolation variations influence on vegetations of the Urals and West Siberia subarctic during the Holocene. The calculation of insolation in the Eurasian Subarctic for the Holocene is carried out based on the solution La2004 for the long-period evolution of the Earth’s orbit. We have estimated the insolation for the latitudes from 55° to 70° N. We have considered the mean daily and mean monthly insolation over 12 ka BP. We assess changes of the insolation in the Eurasian subarctic under the influence of such factor as the topography evolution. The surface topography was analyzed for the recent period (in the Urals and West Siberia) and the Pliocene epoch (in West Siberia). An assessment of the difference in the corresponding digital elevation models showed that the subsidence of the crust took place in West Siberia (the median value of the difference between the digital elevation models was 230.7 m above sea level). The intensity of erosion processes increased in a southerly direction. We have shown that an increase in the number of autumn’s months with high insolation correlates with the taiga biome 4 thousand years ago to wider territories than 8 thousand years ago.
Diatom-inferred palaeolimnological changes in a small lake in the context of the Holocene Baltic Sea transgressions: a case study of Lake Goluboye, Karelian Isthmus (NW Russia)
Authors: Ludikova A V , Shatalova A E , Subetto D A , Kublitskiy Yu A , Rosentau A , Hang T 
Published: February 2020

Abstract
A sedimentary diatom record of Lake Goluboye, Karelian Isthmus (NW Russia) revealed two transgressive stages of the Baltic: the Ancylus Lake and the Litorina Sea, followed by two “small-lake” stages. During the Ancylus Lake transgression, a shallow bay of the Ancylus Lake existed in the Lake Goluboye basin, and species-rich benthic-dominated diatom assemblages formed in oligotrophic, low-mineralisation environments. The isolation from the Ancylus basin took place after ca. 9800 cal. yrs BP, when a small nutrient-rich lake formed in the basin. Two Litorina Sea transgressive phases were inferred from the diatom record of Lake Goluboye, both characterised with similar low-salinity environments. Such a weak signal of the marine transgression, compared with the other coastal sites in the Karelian Isthmus, might have resulted from the sheltered position of the lake. Our data also suppose that the maximum transgression level in the study area was lower than has previously been suggested. With the termination of the Litorina transgression shallow-water conditions with extensive macrophytes growth was established in the lake. Before ca. 4800 cal. yrs BP nutrient-rich small-lake conditions, similar to the post-Ancylus stage, became established.
Preliminary data on formation and depositional environments of lake Chaika in the central part of the Curonian Spit (Kaliningrad region, Russia, South-Eastern Baltic)
Authors: Napreenko M G , Orlov A V , Napreenko-Dorokhova T V , Subetto D A , Sosnina I A 
Published: February 2020

Abstract
Lake Chaika is the only major water body present in the sand barriers of the entire territory of South-Eastern Baltic shoreline. The article provides new insights into the formation of Lake Chaika, based on data acquired through a lithological investigation of the lake sediment core combined with an organic matter content analysis, a macrofossil analysis, a radiocarbon AMS-dating and a bathymetric survey. The study revealed that Lake Chaika was formed around 500 years ago. The kettle of the lake appears to have not been submerged during the Littorina transgressions. During the mid-late Holocene, the kettle of the lake was occupied by the peat-forming ecosystems of alder carrs and sedge fens with scattered alder. The accumulation of ligneous and sedge peat occurred. The sand horizon, separating the gyttja layer from peat deposits, is considered to be a time marker for the so-called “sand disaster”, which began in the study site 200-250 years earlier than in the main territory of the Curonian Spit. There are three main formation phases of the lake’s ecosystem: the period of carrs (5390–510 cal. yr BP), the “sand disaster” period (≈550–500 cal. yr BP) and the proper lake period (500 cal. yr BP – present time).
A modeling approach for reconstruction of annual land surface evapotranspiration using palaeoecological data
Authors: Olchev A V , Getmanova E R , Novenko E Yu 
Published: February 2020

Abstract
A modeling approach to reconstruct the annual land surface evapotranspiration from palaeoecological data was suggested. It is based on assumption that the actual evapotranspiration is proportional to potential surface evapotranspiration and to some decoupling factor characterizing the surface moisture conditions. It was described in our study as a function of the climate moisture index (CMI). The potential evapotranspiration rate was derived using palaeoecological data about past land use and land cover, forest coverage, plant species composition and mean annual air temperature. The value of unknown decoupling factor was approximated using the results of evapotranspiration measurements at selected FLUXNET experimental sites located in the areas with different (ranged from extremely wet to moderately dry) moisture conditions. Comparisons of modeled evapotranspiration rates with results of the field flux measurements showed their good agreement for various forest, shrubland and grassland ecosystems in different geographical regions.
The characteristics of a relic steppe of Northeast Asia: refuges of the Pleistocene Mammoth steppe (an example from the Lower Kolyma area)
Authors: Shchelchkova M , Davydov S , Fyodorov-Davydov D , Davydova A , Boeskorov G 
Published: February 2020

Abstract
An ecosystem of a relic petrophytic steppe was studied in the Lower Kolyma River region. The soils of the steppe area significantly differed from those of the surrounding open larch forests in the following features: the presence of humus-accumulative horizons with a high content of roots; low moisture content; high heat supply; an extremely contrasting temperature regime; neutral reaction; decreased potential acidity; higher humification of organic matter; accumulation of exchangeable bases, soluble salts and organic nitrogen; and the presence of carbonate neoformations in the form of cutans on pebbly units. They also had a high microorganism saturation of the soil profile, a high share of actinomycetes in the microbial community, as is typical for arid soils, and a shift in the ratio of potential enzyme activities toward oxidoreductases, which reflects a deeper destruction of plant residues and more intensive humus formation. The petrophytic steppe had high bioproductivity. The growth rate of the aboveground phytomass (ANP) was closer to the true steppes of Central Asia than to the zonal tundras of the Arctic and Subarctic; such communities can serve as models for paleoreconstructions and study of the Late Pleistocene cold steppes - mammoth fauna large grazing mammals habitats.
Underwater persistent bubble-assisted femtosecond laser ablation for hierarchical micro/nanostructuring
Authors: Zhang Dongshi , Ranjan Bikas , Tanaka Takuo , Sugioka Koji 
Published: February 2020

Abstract
In this study, we demonstrate a technique termed underwater persistent bubble assisted femtosecond laser ablation in liquids (UPB-fs-LAL) that can greatly expand the boundaries of surface micro/nanostructuring through laser ablation because of its capability to create concentric circular macrostructures with millimeter-scale tails on silicon substrates. Long-tailed macrostructures are composed of layered fan-shaped (central angles of 45°–141°) hierarchical micro/nanostructures, which are produced by fan-shaped beams refracted at the mobile bubble interface (≥50° light tilt, referred to as the vertical incident direction) during UPB-fs-LAL line-by-line scanning. Marangoni flow generated during UPB-fs-LAL induces bubble movements. Fast scanning (e.g. 1 mm s−1) allows a long bubble movement (as long as 2 mm), while slow scanning (e.g. 0.1 mm s−1) prevents bubble movements. When persistent bubbles grow considerably (e.g. hundreds of microns in diameter) due to incubation effects, they become sticky and can cause both gas-phase and liquid-phase laser ablation in the central and peripheral regions of the persistent bubbles. This generates low/high/ultrahigh spatial frequency laser-induced periodic surface structures (LSFLs/HSFLs/UHSFLs) with periods of 550–900, 100–200, 40–100 nm, which produce complex hierarchical surface structures. A period of 40 nm, less than 1/25th of the laser wavelength (1030 nm), is the finest laser-induced periodic surface structures (LIPSS) ever created on silicon. The NIR-MIR reflectance/transmittance of fan-shaped hierarchical structures obtained by UPB-fs-LAL at a small line interval (5 μm versus 10 μm) is extremely low, due to both their extremely high light trapping capacity and absorbance characteristics, which are results of the structures’ additional layers and much finer HSFLs. In the absence of persistent bubbles, only grooves covered with HSFLs with periods larger than 100 nm are produced, illustrating the unique attenuation abilities of laser properties (e.g. repetition rate, energy, incident angle, etc) by persistent bubbles with different curvatures. This research represents a straightforward and cost-effective approach to diversifying the achievable hierarchical micro/nanostructures for a multitude of applications.
Embedding human heuristics in machine-learning-enabled probe microscopy
Authors: Gordon Oliver M , Junqueira Filipe L Q , Moriarty Philip J 
Published: February 2020

Abstract
Scanning probe microscopists generally do not rely on complete images to assess the quality of data acquired during a scan. Instead, assessments of the state of the tip apex, which not only determines the resolution in any scanning probe technique, but can also generate a wide array of frustrating artefacts, are carried out in real time on the basis of a few lines of an image (and, typically, their associated line profiles.) The very small number of machine learning approaches to probe microscopy published to date, however, involve classifications based on full images. Given that data acquisition is the most time-consuming task during routine tip conditioning, automated methods are thus currently extremely slow in comparison to the tried-and-trusted strategies and heuristics used routinely by probe microscopists. Here, we explore various strategies by which different STM image classes (arising from changes in the tip state) can be correctly identified from partial scans. By employing a secondary temporal network and a rolling window of a small group of individual scanlines, we find that tip assessment is possible with a small fraction of a complete image. We achieve this with little-to-no performance penalty—or, indeed, markedly improved performance in some cases—and introduce a protocol to detect the state of the tip apex in real time.
Reinforcement learning for semi-autonomous approximate quantum eigensolver
Authors: Albarrán-Arriagada F , Retamal J C , Solano E , Lamata L 
Published: February 2020

Abstract
The characterization of an operator by its eigenvectors and eigenvalues allows us to know its action over any quantum state. Here, we propose a protocol to obtain an approximation of the eigenvectors of an arbitrary Hermitian quantum operator. This protocol is based on measurement and feedback processes, which characterize a reinforcement learning protocol. Our proposal is composed of two systems, a black box named environment and a quantum state named agent. The role of the environment is to change any quantum state by a unitary matrix

U

ˆ

E

=

e

−
i
τ



ˆ

E

where



ˆ

E

is a Hermitian operator, and τ is a real parameter. The agent is a quantum state which adapts to some eigenvector of



ˆ

E

by repeated interactions with the environment, feedback process, and semi-random rotations. With this proposal, we can obtain an approximation of the eigenvectors of a random qubit operator with average fidelity over 90% in less than 10 iterations, and surpass 98% in less than 300 iterations. Moreover, for the two-qubit cases, the four eigenvectors are obtained with fidelities above 89% in 8000 iterations for a random operator, and fidelities of 99% for an operator with the Bell states as eigenvectors. This protocol can be useful to implement semi-autonomous quantum devices which should be capable of extracting information and deciding with minimal resources and without human intervention.
Improving the background of gravitational-wave searches for core collapse supernovae: a machine learning approach
Authors: Cavaglià M , Gaudio S , Hansen T , Staats K , Szczepańczyk M , Zanolin M 
Published: February 2020

Abstract
Based on the prior O1–O2 observing runs, about 30% of the data collected by Advanced LIGO and Virgo in the next observing runs are expected to be single-interferometer data, i.e. they will be collected at times when only one detector in the network is operating in observing mode. Searches for gravitational-wave signals from supernova events do not rely on matched filtering techniques because of the stochastic nature of the signals. If a Galactic supernova occurs during single-interferometer times, separation of its unmodelled gravitational-wave signal from noise will be even more difficult due to lack of coherence between detectors. We present a novel machine learning method to perform single-interferometer supernova searches based on the standard LIGO-Virgo coherent WaveBurst pipeline. We show that the method may be used to discriminate Galactic gravitational-wave supernova signals from noise transients, decrease the false alarm rate of the search, and improve the supernova detection reach of the detectors.