bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Modified SVM Strategy for Single-Phase Cascaded Photovoltaic Inverter
Authors: Xiong L , Zhu Y J , Zhang W Y 
Published: March 2021

Abstract
The DC voltage imbalance of a single-phase cascaded photovoltaic inverter will decrease the quality of output voltage. The general modulation method needs to add power balance control to restrain the imbalance and make the control system complicated. To address the issue, a modified Space Vector Modulation (SVM) method is presented in this paper. The modulation method combines the DC voltage control of each unit with the modulation method to achieve DC voltage control of each unit in vector selection, eliminating the need for additional power balance control, thereby simplifying the control system. The modified space vector modulation can not only make the DC voltage rapidly track the DC voltage instruction of each cell through vector selection but also ensure the quality of output voltage waveform when the DC voltage of each cell is imbalanced. The effectiveness of the modified SVM method is verified, and the simulation model has built by using MATLAB/Simulink.
Design of High Voltage Static Reactive Power Generator Based on SPWM Technology
Authors: Fan L Y , Jiang Y H , Xu A F , Zhao M Z , Fang S A 
Published: March 2021

Abstract
In order to verify the compensation effect of high voltage static var generator. The system structure of cascaded H-bridge is adopted. The bipolar CPS-SPWM and monopole frequency doubling CPS-SPWM modulation modes are compared by simulation. The instantaneous reactive power detection principle is derived theoretically. The reactive power can be compensated quickly by using monopole frequency doubling CPS-SPWM modulation mode and instantaneous reactive power detection. Using Matlab/Simulink to build 10kv High-voltage SVG, the fast and accurate reactive power compensation is realized under the switching of inductive reactive power and capacitive reactive power. The reliability of the design is verified by simulation.
Optimal Scheduling of Pumped Storage in Power System with Large-scale Photovoltaic Based on Carbon Emissions Trading
Authors: Yang T M , Wang Y H , Yang B , Liang Y , Gao J , Ji X 
Published: March 2021

Abstract
In order to improve the photovoltaic penetration of the power system, an optimal scheduling model of pumped storage system with large-scale photovoltaic based on carbon trading is proposed in this paper. Firstly, based on the analysis of low-carbon economy, the stepped carbon emission trading mechanism is introduced into the economic dispatch of power system. And in order to improve the calculating efficiency, an improved K-means clustering algorithm based on maximum and minimum distance criterion is proposed to cluster the photovoltaic power generation scenarios. Then the optimal scheduling model is established. Take the lowest comprehensive operation costs of the system as the objective function, and the operation economy and low carbon of the system are considered. The pumped storage is used as energy storage for peak load shaving in the generation system. At last, an improved IEEE RTS-96 system is taken to finish the case study, and the simulation results show that the model proposed in this paper is reasonable and effective.
Study on Local Measurement Method of Bus Short Circuit Capacity in Substation
Authors: Xu X , Deng P , Chen Z 
Published: March 2021

Abstract
The short-circuit capacity of the bus is a key parameter required for the operation and control of the power system. Online measurement of the short-circuit capacity is crucial for the observability and controllability of the power grid. In this paper, it is proposed that the bus voltage disturbance can be caused by switching on and off the parallel capacitor. According to the voltage disturbance, the on-line measurement of the short circuit capacity of the power grid can be performed. Based on the circuit model of the substation, using the substitution theorem and superposition principle of the linear circuit, the accurate calculation method of bus short-circuit capacity measurement is derived. It is revealed that the phase change of the voltage vector caused by the capacitor switching is the key factor affecting the measurement accuracy. It breaks through the approximate formulas of previous studies. The proposed measurement method has high accuracy; an iterative calculation method for the phase difference of the voltage vector is proposed. The method is more convenient and reliable than direct measurement. Based on MATLAB / Simulink, the substation bus and online measurement model are established. Simulation analysis of various scenarios shows that the proposed method has a measurement error of less than 1%, which is technically easy to implement and practically promote.
Experimental Study on Performance of Trough Solar Thermal Power Station
Authors: Yu Y L , Dai Y Y , Han Y , Wang Y K , Cai B , Rong J 
Published: March 2021

Abstract
With the large number of construction and commercial operation of trough solar thermal power station, the performance test standard and test method of trough solar power station are still missing and imperfect. For the heat storage heat exchange system of trough type solar thermal power station, the index system of heat exchange efficiency, heat storage time and heat collection efficiency are constructed, and the work contents of performance test and technical index are improved. Learn from the idea and concept of performance acceptance test of thermal power generation equipment system in power industry, combined with many years of relevant work experience. It is expected to bring reference and guidance to relevant technical personnel and peers.
Design of Distribution Automation Master Station System Integration Scheme Based on “n + 1” Architecture
Authors: Xia D , Sun B H , Zhu L , Wang B H , Zhou Y H 
Published: March 2021

Abstract
More and more network and provincial companies within the State Grid have adopted the “n + 1” architecture, that is, the deployment of production control at the regional and municipal levels, and the centralized deployment of information management at the provincial level to build the distribution automation master station system. The main station system of information management regional can independently evolve into the distribution cloud main station. In response to the construction trend of “n + 1” architecture, an integrated scheme’ of distribution automation master station system based on “n + 1” mode is proposed, and it is verified and analyzed on the new generation of distribution master station system constructed by State Grid Ningxia Electric Power Company. The verification and analysis on the above show that this integrated solution can solve the problems of cross-regional data synchronization and distributed data storage based on the “N+1” mode of the power distribution master station system, while avoiding the repeated construction of the information management area. At the same time, this construction mode can reduce operating costs, improve the efficiency of distribution network data utilization. At present, this scheme has been applied in Sichuan, Inner Mongolia, Jiangsu and Shanghai Electric Power Company, has a strong demonstration.
Effects of co-fermentation and sequential malolactic fermentation on antioxidant activities and phenolic components of red-fleshed apple cider
Authors: Li Cui-Xia , Zhao Xian-Hua , Chen Xue-Sen 
Published: March 2021

Abstract
Red-fleshed apple (Malus niedzwetzkyana dieck) was used as the fermentation material, and the fermentation mode of red-fleshed apple cider was studied by using alcohol fermentation as control (CK), simultaneous malolactic fermentation (SIM) and sequential MLF (SEQ). The main chemical parameters, antioxidant activities and sensory quality were analyzed to evaluate the quality of red-fleshed apple cider. Compared with the cider without lactic acid bacteria, the total phenolics contents (TPC) and total anthocyanins contents (TAC) in MLF apple cider were significantly decreased, while the total flavonoids content (TFC) were significantly increased. Among them, the TPC and TAC in apple cider obtained by SIM were the highest, while the TFC in apple cider obtained by SEQ. In addition, compared with the control group, the pH of cider obtained by SEQ and SIM was significantly increased by about 0.25 units, while the total acidity was significantly decreased. Therefore the taste of cider obtained from SIM and SEQ were significantly improved, and the cider obtained by SIM got the highest score by sensory analysis, which scored the highest for floral and fruitiness notes. These results indicated that SIM was an effective way to produce red-fleshed apple cider.
Study on the fresh-keeping effect of domestic vase solution on Gladiolus cut flowers
Authors: Liu Jian-Jun , Cheng Li-Jun , Shu Ze-Bing , Wang Shi-Min , Shi Rui 
Published: March 2021

Abstract
According to the basic principle and method of cut flowers preservation, orthogonal experimental design was carried out to study the preservation effect of domestic vase solution made of sugar, aspirin and lemon juice on Gladiolus cut flowers. The results showed that J7 containing 20 g L−1 white granulated sugar and 28 ml L−1 lemon juice could significantly prolong the vase life of Gladiolus cut flowers, promote the opening of florets, improve the daily ornamental value, increase the fresh weight of spray, maintain the water balance and water content of petals, delay the decomposition of protein and the production of malondialdehyde, which was the best domestic vase solution.
Preparation and in vitro evaluation of matrine nanoparticles
Authors: Mao Yuedong , Jin Qing 
Published: March 2021

Abstract
For improving the therapeutic effect as well as bioavailability exhibited by the matrine drugs, and meanwhile enhancing patients’ compliance, the emulsion evaporation-low temperature curing method was adopted to prepare matrine nanoparticles and the prepared matrine nanoparticles underwent lyophilization treatment. Transmission electron microscopy (TEM) and Scanning electron microscope (SEM) was carried out to determine the morphology of matrine nanoparticles, and characterized for particle size and in vitro release. The chemical stability of matrine nanoparticles were studied by Fourier transform infrared (FT-IR) and differential scanning calorimetry (DSC). The results show,the obtained nanoparticles presented amorphous structure, with the particle size of prepared matrine nanoparticles averaged 164 nm and that of the lyophilized preparations averaged 259 nm following the reconstitution. As shown by the in vitro evaluation, both of them exhibited uniform size, spherical shape, and strong chemical and physical stability. Based on the in vitro release results, matrine nanoparticles could continuously release for as long as 48 hours and based on the release kinetics, matrine nanoparticles meet the first-order kinetic release and follow the Ritger-peppas equation.
Identification of chemical components in Pericarpium Citri Reticulatae by HPLC-MS/MS
Authors: Liu Ming-Shi , Geng Lu-Lu , Meng Fan-Xin , Qin Shu-Zhi , Wu Li-Yan , Sun Hao-Yang 
Published: March 2021

Abstract
In this paper, a novel approach using HPLC-MS/MS (high performance liquid chromatography-tandem mass spectrometry) was established for the identification of Pericarpium Citri Reticulatae (PCR). The identities of the components were researched by comparing the mass spectra and retention times with those of reference compounds and mass fragments with those of the known compounds published in literature. Based on the proposed strategy, ten constituents were identified. The established HPLC-MS/MS method could identify the major constituents in PCR with high efficiency and sensitivity. The new method would be suitable for the chemical identification of main components from Pericarpium Citri Reticulatae.
The eradication effects of pullorum disease on chicken flocks mortality in 297 large-scale farms in China
Authors: Zhang Rui , Yang Lin , Zhang Miao-Jie , Fang Xiang-Ming , Liu Yu-Mei 
Published: March 2021

Abstract
Pullorum disease (PD) can cause infection and spread of disease through horizontal propagation between individuals and vertical propagation by hatching eggs to the next generations, regardless of the variety and age, chickens are extremely susceptible to this disease. PD could be prevented, controlled, and eliminated by eradication at both farm and national levels through a strict procedure on positive animals, and healthy animals nurturing. Using sample data from 297 large-scale chicken farms in China during 2011-2015, we recognize the relationship between the eradication effect of PD and chicken flocks mortality based on panel Tobit, fixed effect, and random effect models. By comparing large-scale chicken farms that carrying out eradication of PD or not, we identified how eradication affected chicken flocks mortality. Further, we distinguished the eradication effects of PD on the mortality of chicken flocks with different scales. The results showed that, firstly, eradicating PD could effectively reduce flocks mortality with an average decrease of 0.400% compared with uneradicated farms. Secondly, the farm with a raising-scale ranging from 34,400 to 132,400 chickens exhibits optimal eradication effects. Although we could not extrapolate to all China’s chicken farms, these findings suggest that the mortality would be decreased when carrying out the eradication of PD. Eradicating PD in undersized or oversized chicken farms both probably cause diseconomies of scale.
A review: achievements and new obstacles in China’s food security revealed by grain and animal meat production
Authors: Yang Chaowu , Jiang Xiaosong , Du Huarui , Li Qingyun , Zhang Zengrong , Qiu Mohan , Yu Chunlin 
Published: March 2021

Abstract
Food security represents that everyone is able to purchase and afford enough food necessary for survival and health at any time, which closely connects with harmonious society, stable policies and sustainable economic growth and plays a significant role in heavily populated countries such as China. Currently, while providing 1.4 billion people with adequate food, China has greatly enhanced people’s nutrition and living quality. However, as economy develops, Chinese people are no longer satisfied with fulling up. In this research, China’s achievements in food security are reviewed, including yields of grain and meat, food consumption and poverty elimination. Additionally, the strategies to safeguard food security in China are identified, including safeguarding the quantity and quality of arable land, farmers’ interests, meat production and food reserves. Finally, major obstacles in China’s food security revealed by grain and meat production in the new era are analyzed. Meanwhile, it is argued that the food security will not disappear as a permanent topic because food is enough temporarily; therefore, some implementation suggestions are put forward based on current situation and trend of food security.
Research process of groundwater in Qinghai-Tibet Plateau
Authors: Niu Yongzhen , Weng Baisha , Gong Xiaoyan 
Published: March 2021

Abstract
Qinghai-Tibet Plateau, known as the “third Pole” of the world, is the birthplace of many great rivers, including the Yangtze River, the Yellow River, the Lancang River, the Nu River, the Yarlung Zangbo River and other world famous rivers. Under the background of global warming, the hydrogeological conditions of the Qinghai-Tibet Plateau have been changed to some extent. The degradation of frozen soil and melting of glaciers have a significant impact on the recharge and runoff discharge of groundwater, leading to changes in the dynamic characteristics of groundwater, and thus have a certain impact on the ecological environment of the Qinghai-Tibet Plateau. Therefore, it is of great significance to analyze the evolution law and development trend of groundwater resources in Qinghai-Tibet Plateau. This paper reviews the past research work on groundwater in Qinghai-Tibet Plateau, summarizes the technical methods used in groundwater research, and puts forward the development trend of groundwater research in the future.
3D printing of functional nerve guide conduits
Authors: Huang Yulan , Wu Wenbi , Liu Haofan , Chen Yuwen , Li Bo , Gou Zhiyuan , Li Xun , Gou Maling 
Published: March 2021

Abstract
Nerve guide conduits (NGCs), as alternatives to nerve autografts and allografts, have been widely explored as an advanced tool for the treatment of peripheral nerve injury. However, the repairing efficiency of NGCs still needs significant improvements. Functional NGCs that provide a more favorable microenvironment for promoting axonal elongation and myelination are of great importance. In recent years, 3D printing technologies have been widely applied in the fabrication of customized and complex constructs, exhibiting great potential for tissue engineering applications, especially for the construction of functional NGCs. In this review, we introduce the 3D printing technologies for manufacturing functional NGCs, including inkjet printing, extrusion printing, stereolithography-based printing and indirect printing. Further, we summarize the current methods and strategies for constructing functional NGCs, such as designing special conduit architectures, using appropriate materials and co-printing with different biological cues. Finally, the challenges and prospects for construction of functional NGCs are also presented.
Efficiency Correction Is Required for Accurate Quantitative PCR Analysis and Reporting
Authors: Ruijter Jan M , Barnewall Rebecca J , Marsh Ian B , Szentirmay Andrew N , Quinn Jane C , van Houdt Robin , Gunst Quinn D , van den Hoff Maurice J B 
Published: March 2021

Abstract

Background
Quantitative PCR (qPCR) aims to measure the DNA or RNA concentration in diagnostic and biological samples based on the quantification cycle (Cq) value observed in the amplification curves. Results of qPCR experiments are regularly calculated as if all assays are 100% efficient or reported as just Cq, ΔCq, or ΔΔCq values.

Contents
When the reaction shows specific amplification, it should be deemed to be positive, regardless of the observed Cq. Because the Cq is highly dependent on amplification efficiency that can vary among targets and samples, accurate calculation of the target quantity and relative gene expression requires that the actual amplification efficiency be taken into account in the analysis and reports. PCR efficiency is frequently derived from standard curves, but this approach is affected by dilution errors and hampered by properties of the standard and the diluent. These factors affect accurate quantification of clinical and biological samples used in diagnostic applications and collected in challenging conditions. PCR efficiencies determined from individual amplification curves avoid these confounders. To obtain unbiased efficiency-corrected results, we recommend absolute quantification with a single undiluted calibrator with a known target concentration and efficiency values derived from the amplification curves of the calibrator and the unknown samples.

Summary
For meaningful diagnostics or biological interpretation, the reported results of qPCR experiments should be efficiency corrected. To avoid ambiguity, the Minimal Information for Publications on Quantitative Real-Time PCR Experiments (MIQE) guidelines checklist should be extended to require the methods that were used (1) to determine the PCR efficiency and (2) to calculate the reported target quantity and relative gene expression value.
Validation of the ‘Inflammatory Bowel Disease—Distribution, Chronicity, Activity [IBD-DCA] Score’ for Ulcerative Colitis and Crohn´s Disease
Authors: Lang-Schwarz Corinna , Angeloni Miriam , Agaimy Abbas , Atreya Raja , Becker Christoph , Dregelies Theresa , Danese Silvio , Fléjou Jean-François , Gaßler Nikolaus , Grabsch Heike I , Hartmann Arndt , Kamarádová Kateřina , Kühl Anja A , Lauwers Gregory Y , Lugli Alessandro , Nagtegaal Iris , Neurath Markus F , Oberhuber Georg , Peyrin-Biroulet Laurent , Rath Timo , Riddell Robert , Rubio Carlos A , Sheahan Kieran , Siegmund Britta , Tilg Herbert , Villanacci Vincenzo , Westerhoff Maria , Ferrazzi Fulvia , Vieth Michael 
Published: March 2021

Abstract

Background and Aims
Histological scoring plays a key role in the assessment of disease activity in ulcerative colitis [UC] and is also important in Crohn´s disease [CD]. Currently, there is no common scoring available for UC and CD. We aimed to validate the Inflammatory Bowel Disease [IBD]—Distribution [D], Chronicity [C], Activity [A] score [IBD-DCA score] for histological disease activity assessment in IBD.

Methods
Inter- and intra-rater reliability were assessed by 16 observers on biopsy specimens from 59 patients with UC and 25 patients with CD. Construct validity and responsiveness to treatment were retrospectively evaluated in a second cohort of 30 patients.

Results
Inter-rater reliability was moderate to good for the UC cohort (intraclass correlation coefficients [ICCs] = 0.645, 0.623, 0.767 for D, C, and A, respectively) and at best moderate for the CD cohort [ICC = 0.690, 0.303, 0.733 for D, C, and A, respectively]. Intra-rater agreement ranged from good to excellent in both cohorts. Correlation with the Nancy Histological Index [NHI] was moderate and strong with the Simplified Geboes Score [SGS] and a Visual Analogue Scale [VAS], respectively. Large effect sizes were obtained for all three parameters. External responsiveness analysis revealed correlated changes between IBD-DCA score and NHI, SGS and VAS.

Conclusions
The IBD-DCA score is a simple histological activity score for UC and CD, agreed and validated by a large group of IBD specialists. It provides reliable information on treatment response. Therefore, it has potential value for use in routine diagnostics as well as clinical studies.
Work flexibility and firm growth: evidence from LEED data on the Emilia-Romagna region
Authors: Arrighetti Alessandro , Cattani Luca , Landini Fabio , Lasagni Andrea 
Published: March 2021

AbstractIn the last decades, work flexibility emerged as a key requirement firms must meet to face volatile markets and highly differentiated product demand. This article compares two alternative approaches to strengthen work flexibility: internal flexibility, that is, practices that focus on the employees’ ability to perform a variety of highly qualified tasks in a context of stable employment relationships; and external flexibility, that is, practices that align employment and labor costs to demand fluctuations using a buffer of nonstandard employees involved in routine tasks. We empirically verify whether both practices are able to boost sales growth using a linked employer-employee panel of manufacturing firms from the Emilia-Romagna region (Italy). While internal flexibility positively affects firm growth, external flexibility is at best not significant, and in some empirical specifications, it appears to hamper firm growth. Such a negative effect, however, decreases when we limit the analysis to industries with high demand volatility and cost-based competition. The related managerial and policy implications are discussed.
The Continued Challenges in the Diagnosis of Acute Pelvic Inflammatory Disease: Focus on Clinically Mild Disease
Authors: Soper David E , Wiesenfeld Harold C 
Published: March 2021

Abstract
Many women with lower genital tract infections associated with sexually transmitted pathogens have evidence of upper genital tract inflammation despite the absence of symptoms and signs traditionally associated with pelvic inflammatory disease (PID). New biomarkers are needed to identify these women with clinically mild PID or subclinical PID (silent salpingitis) to facilitate initiation of early treatment and ameliorate the sequelae associated with upper genital tract infection and inflammation.