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Study question Does luteinized unruptured follicle affect the clinical outcome of natural cycles for single high-quality frozen-thawed blastocyst transfer (FBT) cycles? Summary answer Luteinized unruptured follicle negatively affects the pregnancy outcomes of single high-quality FBT. What is known already Recent evidence revealed that natural ovulation cycle with a corpus luteum for frozen-thawed embryo transfer is superior to hormone replacing therapy cycle in preventing early miscarriage and preeclampsia. However, it remains controversial whether a luteinized unruptured follicle of the natural cycle affect the pregnancy outcomes of FBT. Study design, size, duration This was a retrospective cohort study comparing the pregnancy outcomes of singe high-quality FBT among 283 cases of LUF cycles and 1083 cases of ovulation cycles between January 2015 to December 2020 in a private fertility center. The study was approved by the hospital's Ethics Committee. Participants/materials, setting, methods A natural cycle for FBT was performed for all included patients, and was categorized into LUF or ovulation group based on the continuously monitoring of transvaginal ultrasound. Pregnancy outcomes were compared between the two groups. Logistic regression analysis was performed to adjust for important confounders. P < 0.05 was considered statistically significant. Main results and the role of chance Compared to ovulation group, the LUF group was associated with higher proportion of female indication of IVF treatment. There were no statistically significant differences regarding the parental age at oocyte retrieval, body mass index (BMI), cycle rank, infertility duration, proportion of nulliparity and fertilization method, endometrial thickness, and estrogen levels. P levers were higher in the ovulation group than those of LUF (P =0.028). Logistic regression indicated that after controlling for potential confounders, ovulation group was associated with higher incidence of ongoing pregnancy (aOR 1.460, 95% CI: 1.107-1.924) and live birth (aOR 1.455, 95% CI: 1.102-1.919). Ovulation group also had higher clinical pregnancy rate (aOR 1.255, 95% CI: 0.952-1.656) and lower early miscarriage rate (aOR 0.654, 95% CI: 0.394-1.087), but not reach statistical significance. Our results suggested that LUF negatively affected pregnancy outcomes of single high-quality FBT. Limitations, reasons for caution The primary limitation of this study was its retrospective nature, and it was difficult to distinguish some confounding factors. Wider implications of the findings Clinicians should counsel couples about the negative effect of LUF on the pregnancy outcome of FBT, particularly for those with few high-quality embryos. Trial registration number 2018YFC1003900/2018YFC1003904, SZSM201502035

Study question Is there an optimal endometrial preparation protocol of frozen-thawed embryo transfer (FET) for patients with history of intrauterine adhesions (IUAs)? Summary answer Hormone replacement therapy with GnRH agonist pretreatment (HRT+GnRHa) is superior to conventional HRT protocol to improve pregnancy outcomes in patients with IUAs. What is known already FET follow hysteroscopic adhesiolysis or therapeutic treatment is being widely adopted in patients with IUAs. Proper endometrial preparation plays a key role to maximize IVF success rate and improve pregnancy results. However, it remains unclear whether there is an optimal endometrial preparation protocol for patients with history of IUAs. Study design, size, duration This was a retrospective cohort study of 1002 FET cycles with history IUAs in our fertility center between January 2015 to December 2020. The study was approved by the hospital's Ethics Committee. Participants/materials, setting, methods Eight hundred and forty-two conventional HRT cycles and 160 HRT+GnRHa cycles met the inclusion criteria were enrolled. Pregnancy outcomes were compared between the two groups. Logistic regression analysis was performed to adjust for important confounders. P < 0.05 was considered statistically significant. Main results and the role of chance The HRT+GnRHa group was associated with higher cycle rank (1.79 vs 2.17, P =0.026) and longer infertility duration (3.04 vs 3.69, P =0.000) compared with conventional HRT group. While the latter had a higher proportion of blastocyst embryo transferred (P =0.024). There were no statistically significant differences regarding the parental age at oocyte retrieval, body mass index (BMI), number of total embryos transferred and top embryo transferred, proportion of nulliparity, indication of IVF treatment and fertilization method, and endometrial thickness. Logistic regression indicated that after controlling for potential confounders, the HRT+GnRHa group achieved higher incidence of clinical pregnancy (aOR 1.474, 95% CI: 1.002-2.170, P =0.049), ongoing pregnancy (aOR 1.823, 95% CI: 1.207-2.753, P =0.004), and live birth (aOR 1.975, 95% CI: 1.306-2.988, P =0.000) than the conventional HRT group. The miscarriage rate was comparable between the two groups (aOR 0.613, 95% CI: 0.293-1.283, P =0.194). Our results suggested that HRT+GnRHa is over conventional HRT protocol to improve pregnancy outcomes of patients with previous IUAs. Limitations, reasons for caution The primary limitation of this study was its retrospective nature, and it was difficult to distinguish some confounding factors. Besides, there was no grading of IUA severity as most adhesion separation surgeries were not performed in our hospital, and the detailed medical history was not available. Wider implications of the findings Our study offers evidence for the superiority of HRT with GnRH-a pretreatment to conventional HRT protocol in improving the pregnancy prognosis of patients with previous IUAs. Our finding deserves further confirmation in clinical practice. Trial registration number 2018YFC1003900/2018YFC1003904, SZSM201502035

1AbstractSpontaneous Ca2+ local transients (SCaLTs) in isolated oligodendrocyte precursor cells (OPCs) are largely regulated by the following fluxes: store-operated Ca2+ entry (SOCE), Na+/Ca2+ exchange (NCX), Ca2+ pumping through Ca2+-ATPases, and Ca2+-induced Ca2+-release through Ryanodine receptors (RyR) and inositoltriphosphate receptors (IP3R). However, the relative contributions of these fluxes in mediating fast spiking and slow baseline oscillations seen in SCaLTs remain incompletely understood. Here, we developed a stochastic spatiotemporal computational model to simulate SCaLTs in a homogeneous medium with ion flow between the extracellular, cytoplasmic and endoplasmic-reticulum compartments. By simulating the model and plotting both the histograms of SCaLTs obtained experimentally and from the model as well as the standard deviation of interspike intervals (ISI) against ISI averages of multiple model and experimental realizations we revealed that: SCaLTs exhibit very similar characteristics between the two datasets, they are mostly random, they encode information in their frequency, and the slow baseline oscillations could be due to the stochastic slow clustering of IP3R (modeled as an Ornstein-Uhlenbeck noise process). Bifurcation analysis of a deterministic temporal version of the model shows that the contribution of fluxes to SCaLTs depends on the parameter regime and that the combination of excitability, stochasticity, and mixed-mode oscillations are responsible for irregular spiking and doublets in SCaLTs. Additionally, our results demonstrate that blocking each flux reduces SCaLTs frequency and that the reverse (forward) mode of NCX decreases (increases) SCaLTs. Taken together, these results provide a quantitative framework for SCaLT formation in OPCs.

Due to the low output voltage of photovoltaic cells and fuel cells, a high-voltage-gain dc–dc converter is indispensable in the renewable energy power generation systems. In this article, a series of high-voltage-gain capacitor clamped dc–dc converters is constructed based on interleaved boost structures by considering the requirement of low input current ripple in fuel cell application. Furthermore, the construction method of capacitor clamped dc–dc converters is summarized according to the construction processes of these converters. Finally, the capacitor clamped dc–dc converter with the voltage gain of 3/(1− D ) is analyzed in detail. Then, a 250-W prototype is built to validate the theoretical analysis and the construction method.

AIM To investigate the sex-related differences in arterial spin-labelled (ASL) perfusion of metabolically active brain structures in neonatal hypoxic–ischaemic encephalopathy (HIE). MATERIALS AND METHODS Seventy-three term neonates were identified for a retrospective case–control study following an institutional review board (IRB) approved protocol. The cerebral pulsed arterial spin labelling values were compared by permutation test to identify metabolically active brain structures with significant perfusion changes between 10 male controls and eight female controls, and between 31 HIE males and 24 HIE females. RESULTS In the perfusion comparison between HIE male and female neonates, significantly lower perfusion was found in the thalamus in males (p=0.02). The other brain clusters, including basal ganglia, hippocampus cluster, cingulate gyrus cluster, brainstem cluster, sensorimotor cortex cluster, and cerebellum and peduncle cluster, demonstrated no significant differences between HIE males and females. In the perfusion comparison between male and female controls, there were no significant perfusion changes in those brain clusters. CONCLUSION Brain perfusion in neonatal HIE differs between males and females in the thalamus, a metabolically active region within neonates, with males demonstrating lower perfusion. This difference in perfusion may reflect sex-related disparities in response to and recovery from hypoxic–ischaemic events.

In the urban rail transit, the rail current leaks into the earth inevitably due to the incomplete rail-to-earth insulation. It then forms rail potential and stray current issues, which endanger the personal safety and cause metallic corrosions on running rails and the third-party infrastructures. For mitigating the rail potential and stray current, this article proposes a negative resistance converter traction power system (NRC-TPS) to reduce their generating sources by providing zero-resistance loops to the rail current. NRC-TPS is constructed by installing power electronics equipment directly in the conventional traction power system (CON-TPS) without modifying trains, rails, or tunnels, and so on. The operation principles, control strategies, and mitigation performance of NRC-TPS are discussed in detail. The modeling, simulation, and experimental results indicate that the rail potential and stray current are reduced in NRC-TPS compared with those of CON-TPS. The feasibility and practicability of NRC-TPS are also proved through these results.

The rotating detonation ramjet engine (RDRE) is a new-generation aero-engine with tremendous potential. In order to reveal the characteristics of the wave system in RDRE and study the propagation characteristics of the rotating detonation wave (RDW), a three dimensional numerical simulation on a simplified model of RDRE was performed with premixed ethylene/air mixture. The results show that an upstream oblique shock wave (UOSW) is induced by the RDW. It then weakens gradually as propagating upstream and merges with the circumferential tilted normal shock wave (NSW). The UOSW near the outer wall propagates faster upstream, whereas the position of the NSW on the inner and outer walls is almost coincident during the process of propagating downstream. The periodic fluctuations of the pressure peaks and the propagation speed of the RDW were observed, and the irregular pre-combustion occurs near the contact surface. The results also indicate that a sustainable dynamic balance of the periodic fluctuation in the intensity of RDW is formed in the RDRE. The irregular pre-combustion causes the irregular fluctuation of the pressure peaks near the contact surface. The UOSW propagates upstream much faster than the NSW propagating downstream, and the estimated ratio of the circumferential range effected by UOSW to the circumferential range effected by NSW is about 1: 5.

On the background of air defense missile which use radar command guidance, this article focuses on the maneuvering target trajectory simulation and tracking problem by considering possible maneuvering modes and target overload. Taking Serpentine maneuvering (S maneuvering) as an example, the target trajectory is simulated based on overload using stepwise design method, and data are measured through sensor models. Since single model cannot model the maneuvering target motion exactly, the estimation is addressed by combining the interacting multiple model algorithm and unscented Kalman filter algorithm, so as to study the applications of maneuvering target trajectory simulation and tracking in air defense missile systems. The effectiveness of the algorithm is demonstrated with simulated data.

The efforts toward the experimental realization of spin-polarized transports in ideal materials or platforms, such as the magnetized graphene or various quantum Hall states, is a research hotspot in spintronics. Magnetic van der Waals materials open the door for exploring various physical phenomena, technologies, and integrating novel spintronic devices seamlessly within the 2D limit. Here, we demonstrate magnetic proximity effect in chromium trichloride (CrCl3)/bilayer graphene (BLG) heterostructures by low-temperature transport measurements. An effective exchange field induced in BLG has been demonstrated by the Zeeman spin Hall effect via nonlocal measurements. Furthermore, the exchange field modulates the quantum Hall ground state of BLG and thus favors the formation of a canted antiferromagnetic (CAF) phase in an external perpendicular magnetic field (B⊥). Asymmetric nonlocal magneto-transport behaviors are also observed at opposite B⊥ directions, due to the asymmetric modulation on the exchange field by external B⊥ directions. Our work suggests that the 2D magnetic van der Waals materials and graphene hybrid systems offer a unique platform for quantum Hall ferromagnetism physics.

Featured with the simple structure, V-clamp multilevel converter (VMC) shows good prospect in the high-voltage and high-power applications. But VMC is endangered by the deviation of dc-link capacitors voltage, especially under the high modulation index (MI) and high power factor (PF) condition. Thus, a voltage balancing strategy for three-phase seven-level VMC is proposed in this paper. This strategy re-designs the carriers and reference to achieve capacitors voltage balancing with reduced switching actions. Besides, an active compensation control for capacitors voltage is presented to improve the dynamic performance. Compared with the conventional virtual space vector modulation, the proposed strategy significantly reduces the switching loss while provides a better output voltage under the high MI and high PF condition. The simulation model and experimental prototype of VMC with 7.2kW/220V are constructed to verify the validity of the proposed strategy.

To explore the role of receptor-like kinases in the regulation of photosynthesis, an uncharacterized TaRKL1 encoding a receptor-like cytoplasmic kinase was investigated in Triticum aestivum cv. Xiaoyan 101 with Barley stripe mosaic virus-induced gene silencing system (BSMV-VIGS). The results showed that the CO2 assimilation rate, stomatal conductance, and transpiration rate were significantly lower in the BSMV:TaRKL1 plants than those in the BSMV:γ00 plants (control). Moreover, the maximum photochemical efficiency and electron transport flux decreased while the dissipated energy flux was enhanced in the BSMV:TaRKL1 plants compared to the control. Additionally, the contents of chlorophylls and carotenoids were reduced in the BSMV:TaRKL1 plants. However, the hydrogen peroxide content was significantly enhanced in the BSMV:TaRKL1 plants, which resulted from lower ascorbate peroxidase activity. Consistent with the inhibition of photosynthesis, the transcription levels of the photosynthesis-related, antioxidant enzymes, senescence-associated genes, and four abscisic acid biosynthesis genes were downregulated substantially. Collectively, this study for the first time showed that TaRKL1 regulates photosynthesis and H2O2 homeostasis. It may be a potential target gene for radiation-use efficiency improvement in wheat.

患儿 男，3岁10月龄，因“间歇发热2周伴咳嗽、气促”入上海交通大学医学院附属仁济医院（南部院区）定点医院隔离病房。患儿病初发热，确诊为新型冠状病毒肺炎（简称新冠肺炎），热退2 d再次持续高热3 d伴气促、吸气性凹陷，胸部CT示右肺下叶片状密度影，诊断“重型新冠肺炎”，行支气管镜肺泡灌洗，宏基因组病原检测确诊为混合肺炎支原体感染，治疗好转出院。提示临床医生诊治重型新冠肺炎时需警惕混合感染。.

RNA binding protein (RBP) plays a key role in gene regulation and participate in RNA translation, modification, splicing, transport and other important biological processes. Studies have shown that abnormal expression of RBP is associated with a variety of diseases. The Musashi (Msi) family of mammals is an evolutionarily conserved and powerful RBP, whose members Msi1 and Msi2 play important roles in the regulation of stem cell activity and tumor development. The Msi family members regulate a variety of biological processes by binding and regulating mRNA translation, stability and downstream cell signaling pathways, and among them, Msi2 is closely related to embryonic growth and development, maintenance of tumor stem cells and development of hematological tumors. Accumulating evidence has shown that Msi2 also plays a crucial role in the development of solid tumors, mainly by affecting the proliferation, invasion, metastasis and drug resistance of tumors, involving Wnt/β-catenin, TGF-β/SMAD3, Akt/mTOR, JAK/STAT, Numb and their related signaling pathways (Notch, p53, and Hedgehog pathway). Preclinical studies of Msi2 gene as a therapeutic target for tumor have achieved preliminary results. This review summarizes the molecular structure, physiological function, role of Msi2 in the development and progression of various solid tumors and the signaling pathways involved.

The aim of this study is to find an accurate and fast method to diagnose the pathogen of bronchiectasis.Ten bronchiectasic patients diagnosed with Mucoid Pseudomonas Aeruginosa (MPA) in the past two years were analyzed. Accuracy and time were compared between microbiology rapid on-site evaluation (M-ROSE) and sputum bacterial culture.The accuracy rate of M-ROSE in the patients is 100% consistent with bacterial culture results. The average time of M-ROSE is about 4.3 min, which is over 1000 times shorter than that of sputum bacterial culture.M-ROSE may be a better method for etiological diagnosis of MPA.

Targeted at the issue of electric locomotives passing the neutral section in ac electrified railway, a novel intelligent electric phase separation system is proposed in this article, which is also named smart electric neutral section executer (SENSE). It consists of thyristors, several voltage and current transformers, and the control system. On one hand, the thyristors are used to replace the traditional high-voltage circuit breakers so that the power interruption time is significantly reduced when the locomotive passes the neutral section. On the other hand, an automatic pantograph location technique based on the traction network voltage and current information is presented. When the electric locomotive passes the neutral section, its pantograph is located through the voltage and current signals collected by the voltage and current transformers. All pantographs of a train are directly located, which can distinguish different marshaling modes and thus shorten the neutral section length significantly. The basic structure of SENSE and the principle of the pantograph location method are provided in this article. The SENSE equipment is commissioned in the Shenshuo heavy-haul railway in China, where the proposed pantograph location algorithms are verified as well.

In April 2019, a new basal stem and root rot disease, which caused severe wilting of Crossandra infundibuliformis in Jinniu Park in Haikou City, Hainan province. Plants with typical disease symptoms were random collected from Jinniu Park. The pathogen causing basal stem and root rot of C. infundibuliformis was identified as Fusarium solani from the isolates, based on morphological observation, rDNA-ITS, TEF1-α, and fRPB2 gene sequence analysis, and pathogenicity tests. This is the first report of F. solani causing basal stem and root rot on C. infundibuliformis.

In renewable energy generation systems, the DC–DC converter with high voltage gain is indispensable, which is used to convert the low output voltage of photovoltaic (PV) cells and fuel cells to the high DC bus voltage. In this study, a cost-effective clamping capacitor boost (CCB) converter with high voltage gain is proposed. In the basis of the conventional boost converter, a clamping capacitor cell with two capacitors and two diodes is embedded. Then, the voltage gain of the proposed CCB converter can be doubled compared with the conventional boost converter. Further, unlike the switched capacitor high voltage gain converter, there is no large current spikes on the capacitors in the proposed CCB converter, which can reduce the current stresses and the costs of capacitors a lot. The operation principles and characteristics of the proposed CCB converter are analysed in detail and verified by simulation. Finally, a 450 W prototype is implemented to validate the performances and advantages of the proposed CCB converter. The proposed CCB converter provides a cost-effective choice for high voltage gain converters in the renewable energy generation system with PV cells.

The rails are generally employed as the return path of traction current in urban rail transit. As the rails are not totally earth isolated, there exist the rail potential and stray current issues inevitably, which may lead to the electric shock, corrosions, and other hazards. In the past decades, different mitigation measures have been adopted to solve these issues. However, there are some limitations in the existing mitigation measures, such as poor performance, weak applicability, and so on. Therefore, the dc autotransformer (DCAT)-based traction power supply system is proposed in this article for the rail potential and stray current issues. The configurations, principles, and current distributions of DCAT system are analyzed in this article. Then, the comparisons between the DCAT system and the existing system for the rail potential and stray current issues are discussed, considering the different grounding schemes. Finally, the correctness and effectiveness of DCAT system on the rail potential and stray current issues are validated by both simulation and experimental results. Moreover, it is shown that DCAT system transfers the traction current from the rail to other lines and solves the rail potential and stray current issues much effectively.

The rare earth influence on the as-cast microstructures and mechanical properties of aluminum alloys attracted great attentions in the last decades. But up to date no reports can be found on the effect of micro-alloying element La (La addition is below 0.1 wt.%) on the solidification of hypoeutectic Al-Si alloys. This study carried out solidification experiments with Al-6Si alloys micro-alloyed by element La. The α-Al grain refinement, the eutectic Si modification and the tensile properties improvement caused by micro-alloying element La were investigated. The effect mechanisms of La were discussed. It is demonstrated that the addition of La as low as 100 ppm can deprave the more effective heterogeneous nucleation conditions for the eutectic Si caused by the impurity P. The addition of 0.06 wt.% La is sufficient to achieve an ideal α-Al grain refinement, eutectic Si modification and ductility improvement of the alloys. LaAlSi phase forms in the Al-Si alloy with the additive amount of La higher than 0.06 wt.%. It has a tetragonal structure. Micro-alloying element La refines the α-Al grains by working as a surfactant and modifies the eutectic Si by promoting the formation of the significant multiple Si twins.

A large linear negative thermal expansion (NTE) and expanded NTE temperature range (ΔTNTE) were obtained in magnetoelastic CrTe1-xSex (0 ≤ x ≤ 0.15) compounds. For CrTe compound, its thermal expansion coefficient of volume (αV) was calculated to be -28.8 ppm K-1 with the temperature ranging from 280 to 340 K. Substituting Te with Se atoms, the NTE behavior and magnetic properties can be well manipulated. With increasing Se in CrTe1-xSex (0 ≤ x ≤ 0.15) compounds, the ΔTNTE increases from 60 K (280-340 K for x = 0), to 80 K (240-320 K for x = 0.05), to 95 K (200-295 K for x = 0.1), and finally to 100 K (170-270 K for x = 0.15). Furthermore, a linear NTE remains independent of temperature for samples with x ≤ 0.1. The relationship between tunable NTE and magnetic properties was analyzed in detail, indicating that the NTE in CrTe1-xSex compounds originates from the magnetovolume effect (MVE).

T4-binding globulin (TBG) is the main thyroid hormone (TH) transporter present in human serum. Inherited thyroxine-binding globulin (TBG) deficiency is caused by mutations in the TBG (SERPINA7) gene, which is located on the X chromosome. This study was performed to report and evaluate coding region mutations in TBG gene for partial thyroxine-binding globulin deficiency. A pedigree spanning four generations is described in this study. The proband is a female with partial TBG deficiency. All members of this pedigree underwent thyroid function tests, while Sanger sequencing was used to identify the TBG gene mutations. Bioinformatics databases were used to evaluate the deleterious effects of the mutation(s). Two hundred and seven unrelated individuals were used to evaluate the thyroid function of individuals with different TBG mutations. A one-way ANOVA was used to analyze the impact of the TBG mutations on thyroid function. TBG gene sequencing results revealed that the proband had a novel mutation in codon 27 leading to alanine to valine substitution (p.A27V). This mutation was associated with lower serum T4 levels (p

Solidification experiments were carried out for Al–6Si alloys with different La addition levels. The results demonstrate that the average sizes of the α-Al grains and the eutectic Si have a tendency of first decreasing and then almost keeping constant with the La addition. About (0.04–0.06) wt% La addition is enough to achieve a satisfactory grain refinement and modification. An analytical model based on the Wilson equation, the Miedema model and the thermodynamics was proposed to investigate the mechanisms of the α-Al grain refinement and the eutectic Si modification in the hypoeutectic Al–6Si alloys with the trace La addition. The La effect on the grain refinement of α-Al and the modification of the eutectic Si are mainly attributed to the increase in the efficiency of the heterogeneous nucleation substrates to nucleate α-Al and the amount of La atoms in the eutectic Si. The grain refinement and the modification results achieve the maximum when the La concentration is near its maximum solid solubility in the primary α-Al phase.

Urban information extraction from satellite based remote sensing data could provide the basic scientific decision-making data for the construction and management of future cities. In particular, long-term satellite based remote sensing such as Landsat observations provides a rich source of data for urban area mapping. Urban area mapping based on the single-temporal Landsat observations is vulnerable to data quality (such as cloud coverage and stripe), and it is difficult to extract urban areas accurately. The composite of dense time series Landsat observations can significantly reduce the effect of data quality on urban area mapping. Multidimensional array is currently effective theory for geographic big data analysis and management, providing a theoretical basis for the composite of dense time series Landsat observations. Google Earth Engine (GEE) not only provides rich satellite based remote sensing data for the composite of dense time series data, but also has powerful massive data analysis capabilities. In the study, we chose Random Forest (RF) algorithm for the urban area extraction owing to its stable performance, high classification accuracy and feature importance evaluation. In this work, the study area is located in the central part of the city of Beijing, China. Our main data source is all Landsat8 OLI images in Beijing (path/row: 123/32) in 2017.Based on the multidimensional array for geographic big data theory and the GEE cloud computing platform, four commonly used reducer methods are selected to composite the annual dense time series Landsat 8 OLI data. After collecting the training samples, RF algorithm was selected for supervised classification, feature importance evaluation and accuracy verification for urban area mapping. The results showed that 1), compared with the single temporal image of Landsat 8 OLI, the quality of annual composite image was improved obviously, especially for urban extraction in cloudy areas; 2) for the evaluation results of feature importance based on RF algorithm, Coastal, Blue, NIR, SWIR1 and SWIR2 bands were the more important characteristic bands, while the Green and Red bands were comparatively less important; 3) the annual composite images obtained by the ee.Reducer.min, ee.Reducer.max, ee.Reducer.mean and ee.Reducer.median methods were classified and accuracy verification was carried out using the verification points. The overall accuracy of the urban area mapping reached 0.805, 0.820, 0.868 and 0.929, respectively. In summary, the ee.Reducer.median method is a suitable method for annual dense time series Landsat image composite, which could improve the data quality, and ensure the difference of features and the higher accuracy of urban area mapping.

Paralleled DC-DC converters system normally is operated with current-sharing control to achieve equal current distribution among the converters connected in parallel. However, the added current-sharing control might make the paralleled DC-DC converters system suffer from potential degradation of stability and dynamic performances. Hence, the stability analysis of paralleled DC-DC converters system is a hot issue. In order to analyze the stability of paralleled DC-DC converters system accurately and effectively, an extended stability analysis method based on Floquet theory is proposed for paralleled DC-DC converters system in this paper with considering the periodic disturbance. And, a paralleled buck converters system with average current-mode control is taken as an analysis object. The extended stability criterion of paralleled buck converters system based on Floquet theory is derived. Finally, the simulation and experimental results verify the correctness and effectiveness of the proposed stability criterion with considering the periodic disturbance. This paper provides a new choice for the stability analysis of paralleled DC-DC converters system.