bluuebunny/crossref_metadata_2025 huggingface dataset:
Increasing the Physical Representation of Forest‐Snow Processes in Coarse‐Resolution Models: Lessons Learned From Upscaling Hyper‐Resolution Simulations
Authors: Mazzotti Giulia , Webster Clare , Essery Richard , Jonas Tobias
Published: April 2021

Processes shaping forest snow cover evolution often vary at small spatial scales, which are not resolved by most model applications. Representing this variability at larger scales and coarser model resolutions constitutes a major challenge for model developers. In this study, we use a well‐validated hyper‐resolution forest snow model that explicitly resolves the spatial variability of canopy‐snow interactions at the meter scale to explore adequate representation of forest‐snow processes at coarser resolutions (50 m). For this purpose, we assess coarser‐resolution runs against spatially averaged results from corresponding hyper‐resolution simulations over a 150,000 m2 model domain. For the coarser‐resolution simulations, we tested alternative upscaling strategies. Our results reveal considerable discrepancies between strategies that utilize generalized canopy metrics versus strategies that apply a more detailed set of process‐specific canopy descriptors. Particularly, the inclusion of canopy descriptors that represent the various scales and perspectives relevant to the individual processes leads to accurate simulation of forest snow cover dynamics at coarse resolutions. Our results further demonstrate that a realistic representation of snow‐covered fraction in snowmelt calculations is important even for relatively small (∼50 m) grid cells. Ultimately, this work provides recommendations for modeling forest‐snow processes in large‐scale applications, which allow coarse resolution simulations to approximate spatially averaged results of corresponding hyper‐resolution simulations.
Puerto Rico Adapts to a Changing, Challenging Environment
Authors: Rodrigues Meghie
Published: April 2021

The Caribbean is ground zero for some of the biggest impacts of climate change today. Puerto Ricans are building innovative initiatives to protect and prepare their communities for what’s next.
Our Losing Phosphate Wager
Authors: Filippelli Gabriel
Published: April 2021

Global food systems depend on fertilizers with phosphate. We need to act now before this nonrenewable resource runs out.
Statistical Emulation of Winter Ambient Fine Particulate Matter Concentrations From Emission Changes in China
Authors: Conibear Luke , Reddington Carly L. , Silver Ben J. , Chen Ying , Knote Christoph , Arnold Stephen R. , Spracklen Dominick V.
Published: April 2021

Air pollution exposure remains a leading public health problem in China. The use of chemical transport models to quantify the impacts of various emission changes on air quality is limited by their large computational demands. Machine learning models can emulate chemical transport models to provide computationally efficient predictions of outputs based on statistical associations with inputs. We developed novel emulators relating emission changes in five key anthropogenic sectors (residential, industry, land transport, agriculture, and power generation) to winter ambient fine particulate matter (PM2.5) concentrations across China. The emulators were optimized based on Gaussian process regressors with Matern kernels. The emulators predicted 99.9% of the variance in PM2.5 concentrations for a given input configuration of emission changes. PM2.5 concentrations are primarily sensitive to residential (51%–94% of first‐order sensitivity index), industrial (7%–31%), and agricultural emissions (0%–24%). Sensitivities of PM2.5 concentrations to land transport and power generation emissions are all under 5%, except in South West China where land transport emissions contributed 13%. The largest reduction in winter PM2.5 exposure for changes in the five emission sectors is by 68%–81%, down to 15.3–25.9 μg m−3, remaining above the World Health Organization annual guideline of 10 μg m−3. The greatest reductions in PM2.5 exposure are driven by reducing residential and industrial emissions, emphasizing the importance of emission reductions in these key sectors. We show that the annual National Air Quality Target of 35 μg m−3 is unlikely to be achieved during winter without strong emission reductions from the residential and industrial sectors.
CRISPR-Cas9 cytidine and adenosine base editing of splice-sites mediates highly-efficient disruption of proteins in primary and immortalized cells
Authors: Kluesner Mitchell G. , Lahr Walker S. , Lonetree Cara-lin , Smeester Branden A. , Qiu Xiaohong , Slipek Nicholas J. , Claudio Vázquez Patricia N. , Pitzen Samuel P. , Pomeroy Emily J. , Vignes Madison J. , Lee Samantha C. , Bingea Samuel P. , Andrew Aneesha A. , Webber Beau R. , Moriarity Branden S.
Published: April 2021

CRISPR-Cas9 cytidine and adenosine base editors (CBEs and ABEs) can disrupt genes without introducing double-stranded breaks by inactivating splice sites (BE-splice) or by introducing premature stop (pmSTOP) codons. However, no in-depth comparison of these methods or a modular tool for designing BE-splice sgRNAs exists. To address these needs, we develop SpliceR (http://z.umn.edu/spliceR) to design and rank BE-splice sgRNAs for any Ensembl annotated genome, and compared disruption approaches in T cells using a screen against the TCR-CD3 MHC Class I immune synapse. Among the targeted genes, we find that targeting splice-donors is the most reliable disruption method, followed by targeting splice-acceptors, and introducing pmSTOPs. Further, the CBE BE4 is more effective for disruption than the ABE ABE7.10, however this disparity is eliminated by employing ABE8e. Collectively, we demonstrate a robust method for gene disruption, accompanied by a modular design tool that is of use to basic and translational researchers alike.
Active discovery of organic semiconductors
Authors: Kunkel Christian , Margraf Johannes T. , Chen Ke , Oberhofer Harald , Reuter Karsten
Published: April 2021

The versatility of organic molecules generates a rich design space for organic semiconductors (OSCs) considered for electronics applications. Offering unparalleled promise for materials discovery, the vastness of this design space also dictates efficient search strategies. Here, we present an active machine learning (AML) approach that explores an unlimited search space through consecutive application of molecular morphing operations. Evaluating the suitability of OSC candidates on the basis of charge injection and mobility descriptors, the approach successively queries predictive-quality first-principles calculations to build a refining surrogate model. The AML approach is optimized in a truncated test space, providing deep methodological insight by visualizing it as a chemical space network. Significantly outperforming a conventional computational funnel, the optimized AML approach rapidly identifies well-known and hitherto unknown molecular OSC candidates with superior charge conduction properties. Most importantly, it constantly finds further candidates with highest efficiency while continuing its exploration of the endless design space.
MicroRNA-146a limits tumorigenic inflammation in colorectal cancer
Authors: Garo Lucien P. , Ajay Amrendra K. , Fujiwara Mai , Gabriely Galina , Raheja Radhika , Kuhn Chantal , Kenyon Brendan , Skillin Nathaniel , Kadowaki-Saga Ryoko , Saxena Shrishti , Murugaiyan Gopal
Published: April 2021

Chronic inflammation can drive tumor development. Here, we have identified microRNA-146a (miR-146a) as a major negative regulator of colonic inflammation and associated tumorigenesis by modulating IL-17 responses. MiR-146a-deficient mice are susceptible to both colitis-associated and sporadic colorectal cancer (CRC), presenting with enhanced tumorigenic IL-17 signaling. Within myeloid cells, miR-146a targets RIPK2, a NOD2 signaling intermediate, to limit myeloid cell-derived IL-17-inducing cytokines and restrict colonic IL-17. Accordingly, myeloid-specific miR-146a deletion promotes CRC. Moreover, within intestinal epithelial cells (IECs), miR-146a targets TRAF6, an IL-17R signaling intermediate, to restrict IEC responsiveness to IL-17. MiR-146a within IECs further suppresses CRC by targeting PTGES2, a PGE2 synthesis enzyme. IEC-specific miR-146a deletion therefore promotes CRC. Importantly, preclinical administration of miR-146a mimic, or small molecule inhibition of the miR-146a targets, TRAF6 and RIPK2, ameliorates colonic inflammation and CRC. MiR-146a overexpression or miR-146a target inhibition represent therapeutic approaches that limit pathways converging on tumorigenic IL-17 signaling in CRC.
Sub-second and ppm-level optical sensing of hydrogen using templated control of nano-hydride geometry and composition
Authors: Luong Hoang Mai , Pham Minh Thien , Guin Tyler , Madhogaria Richa Pokharel , Phan Manh-Huong , Larsen George Keefe , Nguyen Tho Duc
Published: April 2021

The use of hydrogen as a clean and renewable alternative to fossil fuels requires a suite of flammability mitigating technologies, particularly robust sensors for hydrogen leak detection and concentration monitoring. To this end, we have developed a class of lightweight optical hydrogen sensors based on a metasurface of Pd nano-patchy particle arrays, which fulfills the increasing requirements of a safe hydrogen fuel sensing system with no risk of sparking. The structure of the optical sensor is readily nano-engineered to yield extraordinarily rapid response to hydrogen gas (<3 s at 1 mbar H2) with a high degree of accuracy (<5%). By incorporating 20% Ag, Au or Co, the sensing performances of the Pd-alloy sensor are significantly enhanced, especially for the Pd80Co20sensor whose optical response time at 1 mbar of H2is just ~0.85 s, while preserving the excellent accuracy (<2.5%), limit of detection (2.5 ppm), and robustness against aging, temperature, and interfering gases. The superior performance of our sensor places it among the fastest and most sensitive optical hydrogen sensors.
Proton-assisted calcium-ion storage in aromatic organic molecular crystal with coplanar stacked structure
Authors: Han Cuiping , Li Hongfei , Li Yu , Zhu Jiaxiong , Zhi Chunyi
Published: April 2021

Rechargeable calcium-ion batteries are intriguing alternatives for use as post-lithium-ion batteries. However, the high charge density of divalent Ca2+ establishes a strong electrostatic interaction with the hosting lattice, which results in low-capacity Ca-ion storage. The ionic radius of Ca2+ further leads to sluggish ionic diffusion, hindering high-rate capability performances. Here, we report 5,7,12,14-pentacenetetrone (PT) as an organic crystal electrode active material for aqueous Ca-ion storage. The weak π-π stacked layers of the PT molecules render a flexible and robust structure suitable for Ca-ion storage. In addition, the channels within the PT crystal provide efficient pathways for fast ionic diffusion. The PT anode exhibits large specific capacity (150.5 mAh g-1 at 5 A g-1), high-rate capability (86.1 mAh g-1 at 100 A g-1) and favorable low-temperature performances. A mechanistic study identifies proton-assisted uptake/removal of Ca2+ in PT during cycling. First principle calculations suggest that the Ca ions tend to stay in the interstitial space of the PT channels and are stabilized by carbonyls from adjacent PT molecules. Finally, pairing with a high-voltage positive electrode, a full aqueous Ca-ion cell is assembled and tested.
COVID-19 pathophysiology may be driven by an imbalance in the renin-angiotensin-aldosterone system
Authors: Rysz Susanne , Al-Saadi Jonathan , Sjöström Anna , Farm Maria , Campoccia Jalde Francesca , Plattén Michael , Eriksson Helen , Klein Margareta , Vargas-Paris Roberto , Nyrén Sven , Abdula Goran , Ouellette Russell , Granberg Tobias , Jonsson Fagerlund Malin , Lundberg Johan
Published: April 2021

SARS-CoV-2 uses ACE2, an inhibitor of the Renin-Angiotensin-Aldosterone System (RAAS), for cellular entry. Studies indicate that RAAS imbalance worsens the prognosis in COVID-19. We present a consecutive retrospective COVID-19 cohort with findings of frequent pulmonary thromboembolism (17%), high pulmonary artery pressure (60%) and lung MRI perfusion disturbances. We demonstrate, in swine, that infusing angiotensin II or blocking ACE2 induces increased pulmonary artery pressure, reduces blood oxygenation, increases coagulation, disturbs lung perfusion, induces diffuse alveolar damage, and acute tubular necrosis compared to control animals. We further demonstrate that this imbalanced state can be ameliorated by infusion of an angiotensin receptor blocker and low-molecular-weight heparin. In this work, we show that a pathophysiological state in swine induced by RAAS imbalance shares several features with the clinical COVID-19 presentation. Therefore, we propose that severe COVID-19 could partially be driven by a RAAS imbalance.
Full recovery of ultrafast waveforms lost under noise
Authors: Crockett Benjamin , Romero Cortés Luis , Konatham Saikrishna Reddy , Azaña José
Published: April 2021

The ability to detect ultrafast waveforms arising from randomly occurring events is essential to such diverse fields as bioimaging, spectroscopy, radio-astronomy, sensing and telecommunications. However, noise remains a significant challenge to recover the information carried by such waveforms, which are often too weak for detection. The key issue is that most of the undesired noise is contained within the broad frequency band of the ultrafast waveform, such that it cannot be alleviated through conventional methods. In spite of intensive research efforts, no technique can retrieve the complete description of a noise-dominated ultrafast waveform of unknown parameters. Here, we propose a signal denoising concept involving passive enhancement of the coherent content of the signal frequency spectrum, which enables the full recovery of arbitrary ultrafast waveforms buried under noise, in a real-time and single-shot fashion. We experimentally demonstrate the retrieval of picosecond-resolution waveforms that are over an order of magnitude weaker than the in-band noise. By granting access to previously undetectable information, this concept shows promise for advancing various fields dealing with weak or noise-dominated broadband waveforms.
A heterocyte glycolipid-based calibration to reconstruct past continental climate change
Authors: Bauersachs Thorsten , Russell James M. , Evans Thomas W. , Schwalb Antje , Schwark Lorenz
Published: April 2021

Understanding Earth’s response to climate forcing in the geological past is essential to reliably predict future climate change. The reconstruction of continental climates, however, is hampered by the scarcity of universally applicable temperature proxies. Here, we show that heterocyte glycolipids (HGs) of diazotrophic heterocytous cyanobacteria occur ubiquitously in equatorial East African lakes as well as polar to tropical freshwater environments. The relative abundance of HG26 diols and keto-ols, quantified by the heterocyte diol index (HDI26), is significantly correlated with surface water temperature (SWT). The first application of the HDI26 to a ~37,000 year-long sediment record from Lake Tanganyika provides evidence for a ~4.1 °C warming in tropical East Africa from the last glacial to the beginning of the industrial period. Given the worldwide distribution of HGs in lake sediments, the HDI26 may allow reconstructing SWT variations in polar to tropical freshwater environments and thereby quantifying past continental climate change.
Forecasting the dissemination of antibiotic resistance genes across bacterial genomes
Authors: Ellabaan Mostafa M. H. , Munck Christian , Porse Andreas , Imamovic Lejla , Sommer Morten O. A.
Published: April 2021

Antibiotic resistance spreads among bacteria through horizontal transfer of antibiotic resistance genes (ARGs). Here, we set out to determine predictive features of ARG transfer among bacterial clades. We use a statistical framework to identify putative horizontally transferred ARGs and the groups of bacteria that disseminate them. We identify 152 gene exchange networks containing 22,963 bacterial genomes. Analysis of ARG-surrounding sequences identify genes encoding putative mobilisation elements such as transposases and integrases that may be involved in gene transfer between genomes. Certain ARGs appear to be frequently mobilised by different mobile genetic elements. We characterise the phylogenetic reach of these mobilisation elements to predict the potential future dissemination of known ARGs. Using a separate database with 472,798 genomes from Streptococcaceae, Staphylococcaceae and Enterobacteriaceae, we confirm 34 of 94 predicted mobilisations. We explore transfer barriers beyond mobilisation and show experimentally that physiological constraints of the host can explain why specific genes are largely confined to Gram-negative bacteria although their mobile elements support dissemination to Gram-positive bacteria. Our approach may potentially enable better risk assessment of future resistance gene dissemination.
Quantum circuit cutting with maximum-likelihood tomography
Authors: Perlin Michael A. , Saleem Zain H. , Suchara Martin , Osborn James C.
Published: April 2021

We introduce maximum-likelihood fragment tomography (MLFT) as an improved circuit cutting technique for running clustered quantum circuits on quantum devices with a limited number of qubits. In addition to minimizing the classical computing overhead of circuit cutting methods, MLFT finds the most likely probability distribution for the output of a quantum circuit, given the measurement data obtained from the circuit’s fragments. We demonstrate the benefits of MLFT for accurately estimating the output of a fragmented quantum circuit with numerical experiments on random unitary circuits. Finally, we show that circuit cutting can estimate the output of a clustered circuit with higher fidelity than full circuit execution, thereby motivating the use of circuit cutting as a standard tool for running clustered circuits on quantum hardware.
Electron–hole superfluidity in strained Si/Ge type II heterojunctions
Authors: Conti Sara , Saberi-Pouya Samira , Perali Andrea , Virgilio Michele , Peeters François M. , Hamilton Alexander R. , Scappucci Giordano , Neilson David
Published: April 2021

Excitons are promising candidates for generating superfluidity and Bose–Einstein condensation (BEC) in solid-state devices, but an enabling material platform with in-built band structure advantages and scaling compatibility with industrial semiconductor technology is lacking. Here we predict that spatially indirect excitons in a lattice-matched strained Si/Ge bilayer embedded into a germanium-rich SiGe crystal would lead to observable mass-imbalanced electron–hole superfluidity and BEC. Holes would be confined in a compressively strained Ge quantum well and electrons in a lattice-matched tensile strained Si quantum well. We envision a device architecture that does not require an insulating barrier at the Si/Ge interface, since this interface offers a type II band alignment. Thus the electrons and holes can be kept very close but strictly separate, strengthening the electron–hole pairing attraction while preventing fast electron–hole recombination. The band alignment also allows a one-step procedure for making independent contacts to the electron and hole layers, overcoming a significant obstacle to device fabrication. We predict superfluidity at experimentally accessible temperatures of a few Kelvin and carrier densities up to ~6 × 1010 cm−2, while the large imbalance of the electron and hole effective masses can lead to exotic superfluid phases.
Author Correction: Compilation of longitudinal microbiota data and hospitalome from hematopoietic cell transplantation patients
Authors: Liao Chen , Taylor Bradford P. , Ceccarani Camilla , Fontana Emily , Amoretti Luigi A. , Wright Roberta J. , Gomes Antonio L. C. , Peled Jonathan U. , Taur Ying , Perales Miguel-Angel , van den Brink Marcel R. M. , Littmann Eric , Pamer Eric G. , Schluter Jonas , Xavier Joao B.
Published: April 2021

A Correction to this paper has been published: https://doi.org/10.1038/s41597-021-00903-0.
Transgenic mice overexpressing the LH receptor in the female reproductive system spontaneously develop endometrial tumour masses
Authors: Lottini Tiziano , Iorio Jessica , Lastraioli Elena , Carraresi Laura , Duranti Claudia , Sala Cesare , Armenio Miriam , Noci Ivo , Pillozzi Serena , Arcangeli Annarosa
Published: April 2021

The receptor for the luteinizing hormone (LH-R) is aberrantly over expressed in cancers of the reproductive system. To uncover whether LH-R over expression has a causative role in cancer, we generated a transgenic (TG) mouse which overexpresses the human LH-R (hLH-R) in the female reproductive tract, under the control of the oviduct-specific glycoprotein (OGP) mouse promoter (mogp-1). The transgene was highly expressed in the uterus, ovary and liver, but only in the uterus morphological and molecular alterations (increased proliferation and trans-differentiation in the endometrial layer) were detected. A transcriptomic analysis on the uteri of young TG mice showed an up regulation of genes involved in cell cycle control and a down regulation of genes related to the immune system and the metabolism of xenobiotics. Aged TG females developed tumor masses in the uteri, which resembled an Endometrial Cancer (EC). Microarray and immunohistochemistry data indicated the deregulation of signaling pathways which are known to be altered in human ECs. The analysis of a cohort of 126 human ECs showed that LH-R overexpression is associated with early-stage tumors. Overall, our data led support to conclude that LH-R overexpression may directly contribute to trigger the neoplastic transformation of the endometrium.
Quantifying photoinduced carriers transport in exciton–polariton coupling of MoS2 monolayers
Authors: Yu Min-Wen , Ishii Satoshi , Li Shisheng , Ku Ji-Ren , Yang Jhen-Hong , Su Kuan-Lin , Taniguchi Takaaki , Nagao Tadaaki , Chen Kuo-Ping
Published: April 2021

Exciton–polariton coupling between transition metal dichalcogenide (TMD) monolayer and plasmonic nanostructures generates additional states that are rich in physics, gaining significant attention in recent years. In exciton–polariton coupling, the understanding of electronic-energy exchange in Rabi splitting is critical. The typical structures that have been adopted to study the coupling are “TMD monolayers embedded in a metallic-nanoparticle-on-mirror (NPoM) system.” However, the exciton orientations are not parallel to the induced dipole direction of the NPoM system, which leads to inefficient coupling. Our proposed one-dimensional plasmonic nanogrooves (NGs) can align the MoS2 monolayers’ exciton orientation and plasmon polaritons in parallel, which addresses the aforementioned issue. In addition, we clearly reveal the maximum surface potential (SP) change on intermediate coupled sample by the photo-excitation caused by the carrier rearrangement. As a result, a significant Rabi splitting (65 meV) at room temperature is demonstrated. Furthermore, we attribute the photoluminescence enhancement to the parallel exciton–polariton interactions.
High and specific diversity of protists in the deep-sea basins dominated by diplonemids, kinetoplastids, ciliates and foraminiferans
Authors: Schoenle Alexandra , Hohlfeld Manon , Hermanns Karoline , Mahé Frédéric , de Vargas Colomban , Nitsche Frank , Arndt Hartmut
Published: April 2021

Heterotrophic protists (unicellular eukaryotes) form a major link from bacteria and algae to higher trophic levels in the sunlit ocean. Their role on the deep seafloor, however, is only fragmentarily understood, despite their potential key function for global carbon cycling. Using the approach of combined DNA metabarcoding and cultivation-based surveys of 11 deep-sea regions, we show that protist communities, mostly overlooked in current deep-sea foodweb models, are highly specific, locally diverse and have little overlap to pelagic communities. Besides traditionally considered foraminiferans, tiny protists including diplonemids, kinetoplastids and ciliates were genetically highly diverse considerably exceeding the diversity of metazoans. Deep-sea protists, including many parasitic species, represent thus one of the most diverse biodiversity compartments of the Earth system, forming an essential link to metazoans.
Structure and function analysis of a potent human neutralizing antibody CA521FALA against SARS-CoV-2
Authors: Song Deyong , Wang Wenbo , Dong Chuangchuang , Ning Zhenfei , Liu Xiu , Liu Chuan , Du Guangying , Sha Chunjie , Wang Kailin , Lu Jun , Sun Baiping , Zhao Yanyan , Wang Qiaoping , Xu Hongguang , Li Ying , Shen Zhenduo , Jiao Jie , Wang Ruiying , Tian Jingwei , Liu Wanhui , Wang Lan , Deng Yong-Qiang , Dou Changlin
Published: April 2021

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the ongoing COVID-19 pandemic, which has resulted in more than two million deaths at 2021 February . There is currently no approved therapeutics for treating COVID-19. The SARS-CoV-2 Spike protein is considered a key therapeutic target by many researchers. Here we describe the identification of several monoclonal antibodies that target SARS-CoV-2 Spike protein. One human antibody, CA521FALA, demonstrated neutralization potential by immunizing human antibody transgenic mice. CA521FALAshowed potent SARS-CoV-2-specific neutralization activity against SARS-CoV-2 pseudovirus and authentic SARS-CoV-2 infection in vitro. CA521FALAalso demonstrated having a long half-life of 9.5 days in mice and 9.3 days in rhesus monkeys. CA521FALAinhibited SARS-CoV-2 infection in SARS-CoV-2 susceptible mice at a therapeutic setting with virus titer of the lung reduced by 4.5 logs. Structural analysis by cryo-EM revealed that CA521FALArecognizes an epitope overlapping with angiotensin converting enzyme 2 (ACE2)-binding sites in SARS-CoV-2 RBD in the Spike protein. CA521FALAblocks the interaction by binding all three RBDs of one SARS-CoV-2 spike trimer simultaneously. These results demonstrate the importance for antibody-based therapeutic interventions against COVID-19 and identifies CA521FALAa promising antibody that reacts with SARS-CoV-2 Spike protein to strongly neutralize its activity.
Short-term intake of Lactiplantibacillus plantarum ZDY2013 fermented milk promotes homoeostasis of gut microbiota under enterotoxigenic Bacillus cereus challenge
Authors: Zhang Zhihong , Jin Mingliang , Wang Kaiming , Zhang Na , Zhang Qimeng , Tao Xueying , Wei Hua
Published: April 2021

Probiotics have long been used as functional starter cultures for fermented foods and are associated with numerous health benefits.
The metal–organic framework mediated synthesis of bell string-like hollow ZnS–C nanofibers to enhance sodium storage performance
Authors: Wei Xianbin , Yuan Haocheng , Wang Haijun , Jiang Ruoqian , Lan Jinle , Yu Yunhua , Yang Xiaoping
Published: April 2021

Zinc sulfide (ZnS), with a high theoretical capacity and low redox potential, is considered to be a promising anode material for use in sodium-ion batteries (SIBs).
Synergistic modulation of metal-free photocatalysts by the composition ratio change and heteroatom doping for overall water splitting
Authors: Tian Jianxiong , Zhou Zhaobo , Zhang Sheng , Li Zhixia , Shi Li , Li Qiang , Wang Jinlan
Published: April 2021

The improvement of the photocatalytic activity of carbon nitride based metal-free photocatalysts for overall water splitting is achieved by the synergistic modulation of the composition ratio change and heteroatom doping.
First detection of doubly deuterated methyl acetylene (CHD2CCH and CH2DCCD)
Authors: Agúndez M. , Roueff E. , Cabezas C. , Cernicharo J. , Marcelino N.
Published: April 2021

We report the first detection in space of the two doubly deuterated isotopologues of methyl acetylene. The species CHD2CCH and CH2DCCD were identified in the dense core L483 through, respectively, nine and eight rotational lines in the 72–116 GHz range using the 30 m telescope of the Institut de Radioastronomie Millimétrique (IRAM). We combined the astronomical frequencies observed here with laboratory frequencies from the literature measured in the 29–47 GHz range to derive more accurate spectroscopic parameters for the two isotopologues. We derive beam-averaged column densities of (2.7 ± 0.5) × 1012 cm−2 for CHD2CCH and (2.2 ± 0.4) × 1012 cm−2 for CH2DCCD, which translate to abundance ratios of CH3CCH/CHD2CCH = 34 ± 10 and CH3CCH/CH2DCCD = 42 ± 13. The doubly deuterated isotopologues of methyl acetylene are only a few times less abundant than the singly deuterated ones, specifically around 2.4 times less abundant than CH3CCD. The abundances of the different deuterated isotopologues with respect to CH3CCH are reasonably accounted for by a gas-phase chemical model in which deuteration occurs from the precursor ions C3H6D+ and C3H5D+, when the ortho-to-para ratio of molecular hydrogen is sufficiently low. This points to gas-phase chemical reactions, rather than grain-surface processes, as being responsible for the formation and deuterium fractionation of CH3CCH in L483. The abundance ratios CH2DCCH/CH3CCD = 3.0 ± 0.9 and CHD2CCH/CH2DCCD = 1.25 ± 0.37 observed in L483 are consistent with the statistically expected values of three and one, respectively, with the slight overabundance of CHD2CCH compared to CH2DCCD being well explained by the chemical model.
Delay Margin Computation and Controller Design of Time-delayed AGC System Based on Root Locus Analysis
Authors: Chen Liufu , Zhou Tao , Xu Zhenlin , Zhang Teng
Published: April 2021

To investigate the small-signal stability of automatic generation control (AGC) system with constant communication delay, this paper establishes its state-space based on Padé approximation and conducts eigenvalue calculation. Then, by tracking the change of eigenvalues with time delay, the time-delay margin can be confirmed. Different controller parameters have complex influence on time delay margin and damping performance, so this paper utilizes particle swarm optimization (PSO) to obtain the optimal PI controller parameters to derive delay margin largest and an ideal damping performance. Finally, the simulation studies verify the correctness of time-delay margin calculation and indicate the AGC system has an ideal damping performance with optimal PI controller parameters
Research on Defect Detection Technology of Composite Insulator Sheath
Authors: Li Wenbo , Mao Dun , Jiang Yue , Liu Lanlan , Zhu Jiran , Wan Tao , Zha Fanglin , Chao Yafeng
Published: April 2021

The composite insulator sheath plays an important role in protecting the core rod and insulation. The thickness of the sheath must meet the corresponding standard requirements. During the insulator manufacturing process, the core rod decentration leads to uneven thickness of the sheath, which is easy to cause the risk of composite insulators premature failure during operation. The phased array detection technology can accurately detect the thickness of the sheath, so that defects such as uneven thickness of the sheath (decentration of the core rod) can be detected, and the thickness of the sheath at the end of the composite insulator can also be effectively detected. DR detection technology can effectively identify the interface between the mandrel and the sheath, but there is a risk of the sheath thickness distortion due to inappropriate transillumination parameters.
A novel computing architect in ubiquitous electric IoT
Authors: Bai Jie , Wu Hengtian , Wang Xing , Guo Dandan , Fang Mengran
Published: April 2021

The Internet of things (IOT) has attracted great interest in many applications related to the monitoring and control of physical phenomena. The rapid popularity of Internet of things (IOT) equipment has brought unprecedented pressure to data communication and processing on communication network and central cloud infrastructure. Edge computing, as a potential platform to address such challenges, is facing significant challenges from the tension between resource constrained hardware and low latency applications. In this work, we propose a technical framework to meet the challenges. We suggest that computing and communication resources should be sliced horizontally to form a virtual computing platform to solve the problem of resource shortage.
A Novel Vehicle Gearbox Fault Diagnosis Approach Based on Collective Anomaly Detection
Authors: Hu Zhongfeng , Huang Xiaodi
Published: April 2021

Targeting the problem of gearbox fault diagnosis, we proposed a novel semi-supervised approach based on collective anomaly detection. Based on the limited sample data, the principle of the approach is to detect whether a test dataset contains abnormal patterns by using data distribution as the metric. The sequence obeying unexpected distribution will be identified as collective anomaly, which may be generated by fault patterns. The approach consists of three steps. First, the mixture of multivariate Gaussian distribution is used to fit the structure of sample dataset and test dataset. Then, based on maximum likelihood estimate algorithm, we hope to search the optimal parameters which can fit the data distribution with the highest degree. Finally, the fixed point iteration algorithm is used to solve likelihood estimate functions. Experimental results demonstrate that the proposed approach can be used to find fault patterns of gearbox without the prior knowledge of their generated mechanisms.
Design of Auxiliary Feeding Device Based on Single Chip Microcomputer Control System
Authors: Han Leilei , Zhou Xuan , Meng Chaoying , He Qin , Zhao Zhenfeng
Published: April 2021

People’s daily life activities, such as eating, washing and dressing, are very important to the quality of life. However, for many people with disabilities, including those with upper limbs, these tasks prove to be challenging without the help of human caregivers. However, the shortage of medical workers and rising medical costs have created an urgent need for innovation, making aid more affordable and effective. A typical auxiliary task is dietary assistance, which is the basic daily necessities for maintaining health. People with upper limbs and limbs often have difficulty supporting themselves. Technical intervention can solve the problem by bridging the gap between physical ability and necessary functional ability. This design is based on a single-chip microcomputer control system-assisted feeding manipulator design, which can assist in completing the feeding function, and can also add voice or facial recognition modules to enhance the human-computer interaction experience. The design is mainly composed of editing controller-control and detection-power element. That is, the food is fed through a control program, transmitted to a target position through a power element, and whether feeding is completed is judged through a control and detection device. And we will try to add some functional modules to enhance the human-computer interaction experience.
Analysis and Countermeasures of Abnormal Operation of Unloading Circuit
Authors: Mei Xue , Huili Lin , Xiaoli Zheng
Published: April 2021

Taking the two position two way valve unloading circuit, accumulator unloading circuit, double pump unloading circuit, liquid control sequence valve unloading circuit as examples, the paper analyses the reason of abnormal operation of several hydraulic unloading circuit, puts forward concrete measures, which provides basis for design and operation of hydraulic system.
Clearing Model for Day-ahead Market Considering Hydraulic Coupling Relationship of Multi-operator Cascade Hydropower Stations
Authors: Ningxin Huang , Zhaoxia Jing
Published: April 2021

There is a hydraulic coupling relationship between the upstream and downstream of cascade hydropower stations, and they usually belong to different stakeholders. Traditional clearing mechanism may lead to the mismatch between the bid-winning power and the actual power generated by the downstream power stations, and the low-cost downstream power stations may lose some chance to generate, resulting in damage to social welfare. This paper analyzes the problems faced by multi-operator cascade hydropower stations participating in the day-ahead market. By deducing the generation coupling relationship between upstream and downstream cascade hydropower stations, it is found that the output of downstream hydropower stations can be divided into four parts: fixed part, adjustable part, the part coupled with the output of the upstream power station, the part coupled with the output of the upstream power station and the adjustable output. At last, day-ahead market clearing mechanism and settlement mechanism for downstream power stations to participate in bidding are proposed.
A New Automated Preparation Process by Electrochemical Corrosion of STM Tungsten Tips
Authors: Luo Li , Jingliang Wang , Fang Liu , Song Yang , Qizhi Duan
Published: April 2021

Scanning tunneling microscope (STM) is one of the most important instruments in the field of two-dimensional(2D) materials science while the STM tip is one of the most important parts in STM. Thus, we exhibit a new automated preparation process by electrochemical corrosion of STM tungsten(W) tips based on analog circuit technology in this paper. And the new preparation process is easy and reliable and can save time of researchers. Here, we will elaborate the preparation process and how the system works. In all, we will open up a new road in the field of preparation of STM tips.
Time Delay Estimation Method Used Median Filter in Low Signal to Noise Ratio Pulse Environment
Authors: Liu Hang , Liu Wenhong
Published: April 2021

In practice, the collected signal often contains impulsive noise. The classical time delay estimation algorithm based on the second-order statistics of Gaussian distribution will degrade or even be unreliable, so that it cannot be used. Although the fractional low-order signal processing method can be better adapted to signal processing in the impulse noise environment, the determination of the order p value of the fractional low-order moment depends on the prior knowledge or estimation of the characteristic index α value of the pulse, and when the pulse is stronger or the signal-to-noise ratio is low, the performance cannot meet the requirements well. The paper adopted the method of median filter preprocessing. First, the abnormal points (pulse points) are removed in the noise and return the noise to the Gaussian model distribution; next, use the time delay estimation algorithm under the second-order statistics to avoid the estimate of p-value. Computer simulation experiments show that the method proposed in this paper has better estimation performance in low snr pulse environment.
Capacity Configuration and Selection of Emergency Power Supply for Wind Farms under Typhoon Conditions
Authors: Qian Zhongwen , Guo Qian , Zhang Qi , Zhou Dan , Zhao Songlie , Xie Luyao
Published: April 2021

China’s coastal areas are rich in wind energy resources, and there is a huge market demand for wind power generators. However, due to the impact of typhoons every summer, the wind farms are cut off, causing serious damage to the wind turbines and causing significant economic losses. Based on optimizing the yaw system under typhoon conditions, this paper configures and selects the capacity of diesel generators. First, this article introduces the structure and main functions of the yaw control system. Secondly, through the study of the under-stage wind field model, the algorithm of wind speed extreme value and the calculation method of yaw angle and yaw direction are proposed, and hill climbing algorithm is introduced to optimize the work of the yaw control system. Then, a method for calculating the actual power of a single yaw control system is introduced. On this basis, the capacity configuration plan of the standby diesel generator set was determined, so that it can meet the normal yaw work of the whole field yaw system in the event of a power outage in the field to ensure the safety of the wind turbine.
Research on Influencing Factors and Analysis Model Construction of Distribution Network Investment Demand
Authors: Ma Shun , Chen Ming , Hou Kai , Hu Jinlan , Chen Chao
Published: April 2021

In recent years, as the scale of investment in the distribution network of power grid companies has continued to remain high, there have also been problems of heavy investment and light income to varying degrees, and investment waste has occurred from time to time. Therefore, it is urgent to strengthen the level of investment efficiency of the distribution network. Based on the systematic analysis of the influencing factors of the investment demand of the distribution network, this paper constructs an analysis model of the investment demand of the distribution network to provide reference and reference for the power grid enterprises to improve the investment efficiency and efficiency level.
Research on Construction Method of Urban Driving Cycle of Pure Electric Vehicle
Authors: Li Xiao , Pang Zhifei , Zhao Hongxue
Published: April 2021

The driving cycle of the vehicle is taken as the basis of the vehicle test, which plays an important role in improving vehicle performance and reducing energy consumption. Traditional fuel vehicles have been studied more in the current stage. Test conditions specifically for pure electric vehicles have been less studied. The data acquisition method of pure electric vehicle is studied and used to collect driving data. The driving cycle was established through the extraction and analysis of characteristic parameters. The research results can lay a foundation for the research of driving system optimization and energy consumption reduction of pure electric vehicles.
Study on novel structure of Mn complex, C24H18CrMnN4O5
Authors: Liu Ying , Liu Haixing
Published: April 2021

The novel Mn complex C24H18CrMnN4O5 was investigated by hydrothermal and its crystal structure was characterized using X-ray diffraction technology. The Mn atom is six coordinated by four N atom from two 1, 10-phenanthroline and two O atoms from CrO4-. The hydrogen bonding O-H...O had central effect for crystal stability.
Economic analysis of wind-storage combined power station considering cooperative operation mode
Authors: Peng Liu , Huixu Xiao , Shiwei Qi , Siyu Han , Zhipeng Zhang , Di Yao , Mengdi Fu
Published: April 2021

In engineering construction, the accurate estimation of the investment cost can provide a reasonable basis for the formulation and decision-making of the construction scheme. In this paper, the wind-storage combined operation power station is taken as the research object, the investment cost estimation model is established, and the combined operation mode is analysed to obtain the annual power generation. Finally, according to the investment cost and annual power generation, the cost per unit of electricity model is established. In the past, wind farm and pumped storage power station are usually studied as two independent individuals, but in practical application, there are power conversion, regulation and control operations between them, which are interrelated and interactive. This paper regards the two as a whole and analyses their annual power generation under different cooperative operation modes. The research results of this paper can provide a theoretical basis for the preliminary cost estimation of engineering construction, so as to better determine the construction scheme of power plant.
Research on the construction of evaluation index system for equipment maintenance support capability based on AHP
Authors: Yin Xuyang , Ruan Yongjun , Zhang Yangyang , Zhao Ming , Yan Peng
Published: April 2021

Under the two-level maintenance mode, in order to scientifically evaluate the maintenance support ability of synthetic brigade under the new system, it is an urgent problem to establish a reasonable evaluation index system. First of all, the mission, organizational structure and equipment characteristics of synthetic brigade under the new situation are analyzed. Then, according to the principle and method of establishing index system, the evaluation index is put forward. Finally, AHP is used to determine the index weight, so as to establish the evaluation index system of actual combat training of equipment maintenance support capability of synthetic brigade under the new system.
Analysis of the application of ideal gas equation of state
Authors: Wang Yarong , Wang Peirong
Published: April 2021

In nature, the molecules of real gas have a certain volume and have interaction force with each other. It is difficult to find the molecular motion law of real gas because of its complex properties. An ideal gas is an imaginary substance that does not exist in reality. Its molecules are elastic, non volume particles, and there is no interaction among them. This kind of gas is simple in nature and easy to be analyzed and calculated by simple mathematical relation. The introduction of the concept of ideal gas greatly simplifies the analysis of some thermodynamic problems.
Analysis on Influencing Parameters of Heating Consumption Prediction
Authors: Tian Ye , Li Rui
Published: April 2021

This paper studies the influencing parameters of the heating consumption prediction in heating substation, uses the BP neural network to predict the heating consumption, and establishes four BP neural network structures to change the outdoor average temperature, the lowest temperature and the highest outdoor temperature, the predicted results found that when the input variables include the average outdoor temperature, the lowest outdoor temperature, the highest outdoor temperature, the wind speed, and the heating consumption of the previous three days, the prediction results are better , the relative error is equal or less than 0.25%.
Current Situation of Building Energy Conservation and Green Building Development and its Transformation and Upgrading Countermeasure in Henan Province
Authors: Liu Duan
Published: April 2021

In national environment of energy conservation and emission reduction and green building in China, the development of green building has been gradually promoted in Henan Province. During the 13th Five-Year Plan period, the green building had developed for several decades in Henan Province, and the application of its technology is developing from a diversified perspective. From the analysis of the current development status, although the energy efficiency level of green building has increased by 20% compared with the 12th Five-Year Plan period, green buildings develop in varying degrees in various cities in Henan province. Due to the high cost of green building, the green building policy is not thoroughly implemented in the whole process. It is urgent to improve the current industrial structures in such a state, change the traditional architectural structures, transform and upgrade the construction industry.