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A contact angle observed for a liquid–solid system is not necessarily a unique value, and a few contact angles need to be considered carefully in relation to liquid spreading, adhesion and phase separation. Understanding of the significance of different contact angles has improved in the last few years through direct measurements of interactive forces between droplets/bubbles and solids together with the simultaneous visualization of the changes in their shapes. A microelectronic balance system is employed to measure the force of spreading after either liquid droplet or gas bubble attachment to a substrate surface and the droplet/bubble–substrate adhesion forces after droplet/bubble compression, retraction and detachment. Equipped with a camera in flank and data-acquisition software, the instrument measures directly the forces, monitors droplet/bubble–surface separation with respect to distances over which the droplet/bubble stretches and collects optical images simultaneously. The images are used to analyze capillary pressure and surface tension forces based on the measured droplet/bubble dimensions, shapes of surfaces and values of contact angles. These measurements allow researchers to correlate the advancing, receding and most stable contact angles with liquid–solid interactive forces and analyze their scientific meaning. This review summarizes the very recent literature reports on measurements and interpretation of liquid droplet/gas bubble interactive forces and associated contact angles.

Droplet depinning on superhydrophobic surfaces is pervasive in nature and critical to many applications and hence has been studied extensively over the past few decades. A consensus has been reached that the droplet depinning force mainly stems from the synergistic dynamics of the three-phase contact line and the liquid–vapor interface. Nevertheless, the aforementioned conclusions were made using simple (pure water) droplets depinning on rigid superhydrophobic surfaces, denoted as simple rigid wetting, where the main influencing factors are liquid–vapor interfacial tension, surface texture geometry and material wettability. In recent years, an increasing amount of attention has been paid to complex soft wetting, where liquid physiochemical properties (e.g. viscoelasticity) and solid surface rigidity play an important role. To encourage the investigation of complex soft wetting, in this perspective, depinning of simple droplets on soft surfaces and depinning of viscoelastic droplets on rigid surfaces are briefly introduced. Then, possible factors that affect viscoelastic droplet depinning on soft superhydrophobic surfaces are discussed. Moreover, applications that are highly relevant to complex soft wetting are introduced.

Adhesion of a liquid droplet to a solid surface is a result of solid surface interactions with surrounding fluids, affected by its wettability and morphology. Unfortunately, the direct measurements of adhesion forces are rarely reported in the scientific literature, especially for solids with curvatures. In this study, by using a high-sensitivity microelectronic mechanical balance which vertically deposits and then pulls liquid droplets, the spreading and adhesion forces for water and ethylene glycol droplets on spherical surfaces of polyethylene terephthalate (PET) with radii of curvature from 2 to 8 mm were recorded. Results show that the surface curvature does not affect the advancing and most-stable contact angles but affects the extent of spreading and maximum adhesion forces. The solid surface curvature affects both surface tension and Laplace pressure forces at the spreading point, whereas it mainly affects the Laplace pressure force at the maximum adhesion point.

Background Neoadjuvant therapy followed by esophagectomy has been recognized as an effective treatment for locally advanced esophageal cancer, though still has a dismal prognosis. Antibodies against programmed death 1 (PD-1) protein improve survival in patients with advanced or metastatic esophageal squamous cell carcinoma (ESCC) compared with chemotherapy in second-line therapy. However, neoadjuvant PD-1 inhibitor combined with chemotherapy has not been tested in locally advanced ESCC. We conducted this study to evaluate the efficacy and safety of pd-1 inhibitor in neoadjuvant chemotherapy. Methods In this study, we administered 28 adults with untreated, surgically resectable locally advanced ESCC. PD-1 inhibitor with chemotherapy [albumin paclitaxel 100 mg/m2 on days 1 and 8 + carboplatin with an area under the curve (AUC) of 5 on day 1] were administered every 3 weeks intravenously, and surgery was performed approximately 3-5 weeks after the second dose. The primary purpose of the study was to evaluate the feasibility and safety of this regimen. Results In all, 28 locally advanced ESCC patients were enrolled, 27 patients received surgery, 9 (33.3%) patients' postoperative pathological specimens suggested pCR, and 11 (40.7%) patients' primary tumor suggested complete response. Neoadjuvant PD-1 inhibitor with chemotherapy had an acceptable side-effect profile, 26 patients' tumors were completely resected (96.3% were R0). According to the RESIST v.1.1, the response in all 27 patients was evaluated by a computed tomography (CT) scan before surgery, showing 12 patients with complete response (CR), 12 with partial response (PR), and 3 with stable disease (SD). For surgical procedures, 15 (55.6%) patients underwent minimal invasive surgery, 4 (14.8%) underwent right transthoracic open esophagectomy, and 8 (29.6%) underwent hybrid approaches. Conclusions The novel treatment of PD-1 inhibitor with chemotherapy in the neoadjuvant setting for locally advanced ESCC produced satisfactory outcomes: an unprecedentedly high pCR rate for neoadjuvant chemotherapy, a high R0 resection rate, and a low-toxicity profile were achieved. The long-term efficiency of this novel treatment and the validity of the present findings should be confirmed with longer follow-up and prospective comparative trials.

To detect the internal humidity of the transformer accurately and sensitively and eliminate the interference caused by electromagnetic fields, an interferometric measurement is proposed in this paper for the first time, to the best of our knowledge. The phase value distribution of the interferogram affected by humidity can be extracted quantitatively. The peak-to-peak value (P-P) of the phase image can reflect the humidity, according to theoretical analysis, and the main factors affecting the P-P are current and humidity. It has been tested by currents of 800 A, 1000 A, and 1200 A and different humidities. The paper reveals the relationship between humidity and P-P, proving that it is a reasonable application of real-time measurement of internal humidity in the transformer.

This article investigates the maximum spreading of ferrofluid droplets impacting on a hydrophobic surface under nonuniform magnetic fields. A generalized model for scaling the maximum spreading is developed. It is observed that, if the magnetic field strength is zero, a ferrofluid droplet not only demonstrates similar spreading dynamics as the water droplet but also obeys the same scaling law for the maximum spreading factor. Therefore, this article emphasizes the effects of magnetic field strength. In this regard, a dimensionless parameter (

Arsenic trioxide (ATO) is widely studied for its antitumor efficacy and several recent studies suggested the immune modulatory effects of ATO in animal models. In this study we found ATO treatment induced increased ROS production and DNA damage in esophageal squamous cell carcinoma (ESCC) cells, led to DNA damage mediated degradation of Cyclin D1 and upregulation of PD-L1 in these cancer cells. Mechanistically, we found ATO induced a transient upregulation and nuclear translocation of Cyclin D1 by sumoylation. Followed with increased ubiquitination and degradation of Cyclin D1 through T286 phosphorylation, and at least partly mediated by Stat1 Y701 phosphorylation. We observed inversed correlations between Cyclin D1 and PD-L1 expression levels in human ESCC tissues. With 4NQO induced PD-L1 humanized mouse oral and esophageal squamous carcinoma model, we found combinatory administration of ATO and check point inhibitor resulted in a significant reduction of tumor volumes. Inversed correlation between Cyclin D1 with PD-L1 was also observed in the 4NQO induced mouse ESCC and OSCC model. Together, these data suggested ATO induced degradation of Cyclin D1 and functional suppression of CDK4/6 pathway sensitized OSCC and ESCC to checkpoint inhibitor treatment.

Background Airway-gastric fistulas (AGFs) are rare but life-threatening complications after esophagectomy for esophageal cancer. Their effective and reasonable management is challenging and still controversial. This study reports the classification and management strategies of post-esophagectomy AGF based on a retrospective analysis of 26 cases in two large volume centers in China. Methods Between January 2000 and December 2017, 6,316 consecutive patients with esophageal carcinoma underwent esophagectomy. AGF was verified in 26 patients. The patients with AGF were divided into two types based on the anatomic characteristics of the fistula. Type I was characterized by the presence of fistula orifices in digestive tract that were higher than those in the airway and were treated with conservative management. Type II had both fistula orifices located on the same horizontal plane and were treated with surgical management. Pearson Chi-Square (R software) was used to compare mortality rates. Results From January 2000 and December 2017, 26 cases occurred AGF in 6,316 consecutive patients with esophageal carcinoma underwent esophagectomy and the incidence of AGF was 0.4%. Ten of 12 patients with type I AGF survived. Nine of 14 patients with type II AGF died. There was a significantly difference in the mortality rates between patients with AGF type I and II, which was 16.7% (2/12) and 64.3% (9/14) (χ2=6.003, P=0.014), respectively. Conclusions AGF may be classified into two types according to the anatomic characteristics. Type I patients may be cured by conservative management and type II patients, require surgical intervention with pedicled tissues flap wrapping of the airway.

Aiming at the problems of large leakage current and low efficiency of existing transformerless single-phase grid-connected photovoltaic inverters, a novel transformerless single-phase grid-connecte...

Droplet transport on a cylindrical wire has applications in numerous fields such as fog collection, mist elimination, filtration, and oil/water separation. This work reports a droplet transport phenomenon on a superhydrophilic wire that shows a transient velocity powered not by the gradient of substrate geometry or wettability but primarily by the surface-to-kinetic energy transition that occurs along the axial direction upon coalescence. The transition efficiency is mainly limited by the viscous friction at the local liquid wedge, a relationship that a modified Ohnesorge number can capture.

With the rapid growth of urban power transmission cable scale, the harmonic pollution in the high-voltage power grid is more transmitted to other power grids of different voltage levels, which makes the harmonic transmission more complicated, increases the harmonic emission level, and makes it difficult to quantitatively analyze and study the allowable value of users’ electrical pollution emission. Therefore, in this paper, by establishing the harmonic conduction model of the urban high-voltage power grid and considering the equivalent circuit of transformer and transmission cable in the urban power grid, the parameters of transmission cable harmonic transfer coefficient and the allowable emission value of power quality pollution of the urban power grid are deduced and quantitatively analyzed. Then the harmonic transmission and mutual influence of urban power network harmonics in power transmission cable are analyzed through examples, which is helpful to determine the allowable value of harmonic pollution emission scientifically and reasonably.

Recently, various types of porous surfaces have been demonstrated for lubricant (e.g., oil) impregnated omniphobic surfaces. However, the retention of the lubricating liquid within the porous layer and the omniphobic durability still remain challenges. Here, the omniphobic durability of the oil-impregnated surfaces of various types of anodic aluminum oxide (AAO) nanostructures is investigated. The oil impregnation into nanoporous AAO with high porosity enhances droplet mobility by eliminating the pinning site of a contact line on the solid surface, whereas that with low porosity allows the pinning site to result in less mobility. In the cases of nanopillared AAO layers, although the oil-impregnation enhances the repellency to liquids, oil is prone to be depleted by external force such as fluid flow due to the nature of the interconnected oil through the passages between pillars, which limits the omniphobic durability. Among the various types of nanostructured AAO surfaces, the AAO with isolated pore geometry with high porosity exhibits the most durable omniphobicity for a wide range of liquids including organic liquids with low surface tensions. Moreover, the nanoporous AAO surface shows great anti-bacterial adhesion property, reducing the adhesion of bacteria (Escherichia coli K-12) up to 99.2% compared to a bare aluminum surface.

Understanding how surface properties determine the mobility of a fakir droplet on patterned surfaces, which is typically characterized by advancing and receding contact angles, is important in the design of superhydrophobic surfaces for tailored applications. However, most analytical models of the contact angles are limited to a specific motion direction and surface type, e.g., receding on a pillared surface. Although it was suggested that the contact angles should be determined by the local configuration and dynamics of the droplet boundary, their link remains vague due to the lack of detailed visualizations. In this study, the contact line dynamics of a fakir droplet in both advancing and receding motions on not only micropillared but also micropored surfaces are visualized in reflection interference contrast microscopy along with the contact angle measurement. Based on the energy change induced by the displacement of a contact line and the deformation of a liquid-gas interface in between contact lines, theoretical models of the contact angles to encompass the two different motion directions and surface types are formulated. Moreover, further generalized models are established to serve as effective analytical models to predict the contact angles only based on the given structure dimensions and the inherent surface hydrophobicity.

Background Researches on programmed cell death (PD-1) as neoadjuvant immunotherapy for resectable non-small cell lung cancer is underway, which brings hope for individuals with the disease. However, a study dedicated to lung squamous cell carcinoma (LUSC) specifically has yet to be conducted. Now, data from our pilot prospective research neoadjuvant study provide new insights in the field of neoadjuvant regimen for LUSC. Methods Between June 2019 and July 2020, 37 adults with untreated, surgically resectable stage IIB-IIIB LUSC were enrolled into this prospective study. Patients received 2 cycles of pembrolizumab (2 mg/kg) with chemotherapy (albumin-bound paclitaxel 100 mg/m2 on days 1 and 8 + carboplatin AUC 5) via intravenous administration every 3 weeks, and underwent surgical treatment 3-4 weeks after the second cycle. The primary endpoint of the study was the tumor pathologic complete response (pCR) rate. The toxicity profile, tumor major pathological remission, complete resection rate, response rate, and operative and postoperative complications were also evaluated. Results The postoperative pathological specimens of 17 (45.9%) patients suggested pCR. Neoadjuvant pembrolizumab with chemotherapy had an acceptable side-effect profile, and no patients withdrew from the study preoperatively due to disease progression or toxicity. A major pathological response occurred in 24 (64.9%) resected tumors. All tumors were completely resected (R0, 100%). According to the Response Evaluation Criteria in Solid Tumors (RESIST), a response was evaluated before surgery in 32 (86.5%) patients by computed tomography. Twenty-five (67.6%) patients underwent thoracoscopic surgery. No deaths or postoperative major complications requiring reoperation occurred. Recurrence or metastasis was found in 2 patients during follow-up of 2-14 months. Conclusions The early outcomes of pembrolizumab with chemotherapy in the neoadjuvant setting as a novel treatment for resectable stage IIB-IIIB LUSC showed a high pCR rate that has not been seen previously, as well as a high R0 resection rate and a low toxicity profile. The long-term efficacy of this novel treatment and the validity of the present findings should be confirmed with longer follow-up and prospective comparative trials.

For applications involving droplet detachment from solid surfaces, it is vital to study the droplet characteristics (e.g., contact angle and base width) when the droplet is experiencing the maximum force that detaches the droplet (maximum adhesion state). Historically, such investigations were mainly conducted on flat two-dimensional surfaces and the characteristics on curved surfaces with the third dimension remain unknown. Thus, the generalized description of such characteristics has not been established yet. Here, by vertically pulling liquid droplets using a microbalance, we study the droplet characteristics at the maximum adhesion on curved homogeneous surfaces. Variables in this study include liquid surface tension, initial droplet base area, and the asymmetry in solid surface curvature. Results show that the contact angle is identical everywhere along the droplet perimeter on curved surfaces irrespective of the asymmetry in surface curvature. In addition, we found that the droplet base is nonaxisymmetric (not circular) at the maximum adhesion, opposing previous understanding that was formulated for flat surfaces. As a result, we propose a more generalized and quantitative description of the droplet characteristics at the maximum adhesion, derived from the component of the surface tension force acting along the droplet perimeter.

Lung cancer (LC) ranks first among all causes of cancer-related death, with non-small cell lung cancer (NSCLC) taking up 85% of lung cancer cases. Although lncRNA MCM3AP antisense RNA 1 (MCM3AP-AS1) has been reported to be an oncogenic factor in NSCLC, its detailed mechanism in NSCLC is unknown. In this study, quantitative real-time polymerase chain reaction (qRT-PCR) was performed to determine MCM3AP-AS1, microRNA (miR)-195-5p and E2F transcription factor 3 (E2F3) mRNA expressions in NSCLC tissues and cells. Western blot was utilized to determine the expression levels of E2F3, BCL2-associated X protein (Bax), B-cell lymphoma-2 (Bcl-2), E-cadherin and N-cadherin. CCK-8 and Transwell assays were conducted to examine cell proliferation, migration and invasion, respectively. Dual-luciferase reporter assay and RNA immunoprecipitation experiments were used to determine the regulatory relationships between MCM3AP-AS1 and miR-195-5p, and miR-195-5p and E2F3. We demonstrated that MCM3AP-AS1 was overexpressed in NSCLC tissues and cells, and MCM3AP-AS1 overexpression accelerated the proliferation, migration and invasion of NSCLC cells. In addition, MCM3AP-AS1 overexpression markedly up-modulated Bcl-2 expression and repressed Bax expression; MCM3AP-AS1 overexpression also significantly up-regulated N-cadherin expression and suppressed E-cadherin expression in NSCLC cells. What is more, in NSCLC cells, miR-195-5p was a target of MCM3AP-AS1, and the latter worked as a molecular sponge for miR-195-5p to regulate E2F3 expression. Collectively, MCM3AP-AS1, serving as a competitive endogenous RNA (ceRNA) to regulate miR-195-5p/E2F3 axis, promotes NSCLC progression, which is a promising therapeutic target for NSCLC., Graphical bastract

Background The incidence rate of adenocarcinoma of the esophagogastric junction (AEG) has significantly increased over the past two decades. Surgery remains the only curative treatment. However, there are currently few studies on Chinese AEG patients. The purpose of this study was to retrospectively analyze the survival and prognostic factors of AEG patients in our center. Methods Between January 2008 and September 2014, 249 AEG patients who underwent radical resection were enrolled in this retrospective study, including 196 males and 53 females, with a median age of 64 (range 31–82). Prognostic factors were assessed with the log-rank test and Cox univariate and multivariate analyses. Results The 5-year survival rate of all patients was 49%. The median survival time of all enrolled patients was 70.1 months. Pathological type, intraoperative blood transfusion, tumor size, adjuvant chemotherapy, duration of hospital stay, serum CA199, CA125, CA242 and CEA, pTNM stage, lymphovascular or perineural invasion, and the ratio of positive to negative lymph nodes (PNLNR) were significantly associated with overall survival when analyzed in univariate analysis. Conclusions Our study found that adjuvant chemotherapy, PNLNR, intraoperative blood transfusion, tumor size, perineural invasion, serum CEA, and duration of hospital stay after surgery had significance in multivariate analysis and were independent risk factors for survival.

Droplet generation in a T-junction with surfactants is simulated using our recently developed lattice Boltzmann method. The method is first used to explore the effect of surfactant concentration [Formula: see text] on droplet generation. As [Formula: see text] increases, droplet generation tends to shift from squeezing to dripping regime and then to jetting regime. In the clean system, the upstream pressure varies almost periodically with time. However, in the surfactant-laden system, the upstream pressure no longer varies periodically but overall increases with time for droplet generation in squeezing and dripping regimes. This is because the addition of surfactants results in an additional pressure drop between the front and rear of the generated droplet. Then, droplet generation in both clean and surfactant-laden systems is compared to explore the surfactant role under different values of the capillary number [Formula: see text]. In either clean or surfactant-laden system, the pressure upstream of the junction rapidly decreases as [Formula: see text] increases. In the presence of surfactants, the upstream pressure overall increases with time for droplet generation in squeezing and dripping regimes, but the increased amplitude decreases with [Formula: see text]. Finally, we establish the phase diagrams describing how the droplet generation regime varies with flow rate ratio and [Formula: see text] in both clean and surfactant-laden systems. It is found that the addition of surfactants reduces the critical capillary number distinguishing squeezing from dripping and the critical capillary number distinguishing dripping from jetting.

BACKGROUND: The gut microbiome is associated with the response to immunotherapy in a variety of advanced cancers. However, the influence of the gut microbiome on locally advanced esophageal squamous cell carcinoma (ESCC) during programmed cell death protein 1 (PD-1) antibody immunotherapy plus chemotherapy is not clearly demonstrated. To explore the crosstalk between the gut microbiome and clinical response in locally advanced thoracic ESCC during neoadjuvant camrelizumab and chemotherapy METHODS: Patients who were diagnosed with locally advanced thoracic ESCC and had not received treatment were enrolled. The treatment regimen was two cycles of camrelizumab combined with carboplatin and albumin paclitaxel before surgery. The research endpoints were pathological complete response (pCR) and major pathological response (MPR). Fecal samples were collected at three time points: before neoadjuvant therapy, after two cycles of neoadjuvant therapy, and after surgery. We performed 16S ribosomal ribonucleic acid (rRNA) V3–V4 sequencing of the gene amplicons of fecal samples, as well as bacterial diversity and differential abundance analyses. RESULTS: A total of 46 patients were recruited, and 44, 42, and 35 fecal samples were collected at the three time points, respectively. Statistically significant differences were observed in the amplicon sequence variant (ASV)-level alpha diversity indices, including Chao1, Shannon, and Good’s coverage, between the three time points. The non-pCR-enriched gut microbiota included Proteobacteria, Dialister, Aeromonadales, Pseudomonadales, Thermi, Deinococci, Moraxellaceae, Rhodocyclales, Rhodocyclaceae, and Acinetobacter. The non-MPR-enriched gut microbiota included Pseudomonadales and the mitochondria family. The MPR-enriched gut microbiota included the Barnesiellaceae, Pyramidobacter, Dethiosulfovibrionaceae, Odoribacteraceae, Butyricimonas, Prevotella, Barnesiella, and Odoribacter. Patients with ≥3 grade adverse events (AEs) exhibited enrichment in the Succiniclasticum, Nakamurella, Rhizobium, Granulicella, Phyllobacteriaceae, Pelagibacteraceae, Actinosynnemataceae, Aquirestis, Flavisolibacter, Chelativorans, Coxiellaceae Acidicapsa, Acidobacteriaceae, Lentzea, Staphylococcus, Plesiomonas, Dysgonomonas, Pseudonocardia, and Ellin6075. CONCLUSIONS: We found that the diversity of the gut microbiome declined after neoadjuvant PD-1 antibody immunotherapy plus chemotherapy and surgery. Patients with pCR had different types and proportions of gut microbiota before treatment compared to those without pCR. We also observed the difference between patients with or without ≥ grade 3 AEs. The taxonomic features of the gut microbiome are potential biomarkers that could predict the pathological response and AEs.

278 Background: To explore the efficacy and safety of neoadjuvant camrelizumab and chemotherapy for locally advanced thoracic esophageal squamous cell carcinoma (ESCC) by an open label, single-arm, phase 2 clinical trial (ClinicalTrials.gov, Identifier number: NCT04506138). Methods: The eligible patients were arranged to receive 2 cycles of camrelizumab (200mg, day 1) combined with carboplatin (AUC = 5, day 1) and albumin paclitaxel (100 mg/m2, day 1, 8). All treatments were given intravenously in 3-week cycle. Patients underwent surgery within 4-6 weeks after the completion of neoadjuvant treatment. The primary endpoint was pathologic complete response (pCR), and secondary endpoints were major pathological response (MPR), safety and feasibility. The quality of life (QoL) was assessed by the Functional Assessment of Cancer Therapy-Esophageal (FACT-E) scale and EQ-5D-3L scale. Results: A total of 46 patients were recruited, among whom the clinical stage II, III, and IVa at baseline were 11 (23.9%), 33 (71.7%), and 2 (4.3%), respectively. Forty-five patients completed 2 cycles of neoadjuvant treatment. One patient received 1 cycle of neoadjuvant treatment and then lost to be followed up. Eight patients did not receive surgery. Except 1 patient accept exploratory surgery, 37 patients (37/46, 80.4%) achieved R0 resection. Eight patients (8/37, 21.6%) had pCR in both primary tumors and lymph nodes. MPR of primary tumors and lymph nodes was observed in 18 patients (18/37, 48.6%). During neoadjuvant treatment period, all 46 patients presented with treatment-related AEs (TRAEs) of any grade. Seven patients (7/46,15.2%) experienced grade ≥ 3 TRAEs. One patient suffered grade 5 immune-associated pneumonia. The most common TRAEs were anemia (32/46, 70.0%), followed by thrombocytopenia (15, 32.6%), leukopenia (14, 30.4%), neutropenia (13, 28.3%), rash (12, 26.1%), reactive cutaneous capillary endothelial proliferation (RCCEP) (7, 15.2%). The median interval between the first cycle of neoadjuvant treatment and surgery was 64 days (range, 56-77 days). Symptom scores in FACT-E scale were improved by neoadjuvant treatment (t = -2.60, P = 0.01). PD-L1 CPS (< 10 vs ≥ 10), PD-L1 TPS (< 1% vs ≥ 1%) and TMB (split according to top 20% of TMB value) had no effect on the pCR rate and MPR rate. Conclusions: Neoadjuvant camrelizumab combined with chemotherapy achieved a promising pathologic response, which was effective and safe. Meanwhile, neoadjuvant treatment improved QoL of patients. Some larger multi-center trials are undergoing for further confirmation of efficacy and safety. Clinical trial information: NCT04506138.

Railway static power conditioner(RPC) can effectively overcome the shortcomings of traditional conditioner which has poor negative sequence and harmonic compensation effect, it provides a new way to control the power quality of high-speed railway. However, the traditional two-level RPC device occupies a large area, and it will also encounter direct current bias magnetic problem, which distorts the voltage of the system and the excitation current distorts to form peak waves. At this time, the harmonic content increases dramatically and the reactive power loss of the transformer increases. In this paper, the MMC topology and RPC structure are combined to form the MMC-RPC topology, which is directly connected to the traction power supply arm, eliminating such deficiencies as large floor area, large loss and distortion of output current waveform of the booster transformer. At the same time, this paper also studied the capacitor voltage equalization control and circulation suppression strategy of MMC-RPC topology. Finally, the MMC-RPC topology simulation model is built to verify the feasibility and effectiveness of the topology structure and control strategy.