Simulation of gas-solid flow characteristics of the circulating fluidized bed boiler under pure-oxygen combustion conditions

Under the pressure of carbon neutrality,many carbon capture,utilization and storage technologies have witnessed rapid development in the recent years,including oxy-fuel combustion(OFC)technology.However,the conventional OFC technology usually depends on the flue gas recirculation system,which faces significant investment,high energy consumption,and potential low-temperature corrosion problem.Considering these deficiencies,the direct utilization of pure oxygen to achieve particle fluidization and fuel combustion may reduce the overall energy consumption and CO_(2)-capture costs.In this paper,the fundamental structure of a self-designed 130 t·h^(-1) pure-oxygen combustion circulating fluidized bed(CFB)boiler was provided,and the computational particle fluid dynamics method was used to analyze the gas-solid flow characteristics of this new-concept boiler under different working conditions.The results indicate that through the careful selection of design or operational parameters,such as average bed-material size and fluidization velocity,the pure-oxygen combustion CFB system can maintain the ideal fluidization state,namely significant internal and external particle circulation.Besides,the contraction section of the boiler leads to the particle backflow in the lower furnace,resulting in the particle suspension concentration near the wall region being higher than that in the center region.Conversely,the upper furnace still retains the classic core-annulus flow structure.In addition to increasing solid circulation rate by reducing the average bed-material size,altering primary gas ratio and bed inventory can also exert varying degrees of influence on the gas-solid flow characteristics of the pure-oxygen combustion CFB boiler.

Candidate genes conferring ethylene-response in cultivated peanuts determined by BSA-seq and fine-mapping

Ethylene plays essential roles in plant growth,development and stress responses.The ethylene signaling pathway and molecular mechanism have been studied extensively in Arabidopsis and rice but limited in peanuts.Here,we established a sand-culture method to screen pingyangmycin mutagenized peanut lines based on their specific response to ethylene(“triple response”).An ethylene-insensitive mutant,inhibition of peanut hypocotyl elongation 1(iph1),was identified that showed reduced sensitivity to ethylene in both hypocotyl elongation and root growth.Through bulked segregant analysis sequencing,a major gene related to iph1,named AhIPH1,was preliminarily mapped at the chromosome Arahy.01,and further narrowed to a 450-kb genomic region through substitution mapping strategy.A total of 7014 genes were differentially expressed among the ACC treatment through RNA-seq analysis,of which only the Arahy.5BLU0Q gene in the candidate mapping interval was differentially expressed between WT and mutant iph1.Integrating sequence variations,functional annotation and transcriptome analysis revealed that a predicated gene,Arahy.5BLU0Q,encoding SNF1 protein kinase,may be the candidate gene for AhIPH1.This gene contained two single-nucleotide polymorphisms at promoter region and was more highly expressed in iph1 than WT.Our findings reveal a novel ethylene-responsive gene,which provides a theoretical foundation and new genetic resources for the mechanism of ethylene signaling in peanuts.

Silencing of the long non-coding RNA LINC00265 triggers autophagy and apoptosis in lung cancer by reducing protein stability of SIN3A oncogene

Background:Long non-coding RNAs are important regulators in cancer biology and function either as tumor suppressors or as oncogenes.Their dysregulation has been closely associated with tumorigenesis.LINC00265 is upregulated in lung adenocarcinoma and is a prognostic biomarker of this cancer.However,the mechanism underlying its function in cancer progression remains poorly understood.Methods:Here,the regulatory role of LINC00265 in lung adenocarcinoma was examined using lung cancer cell lines,clinical samples,and xenografts.Results:We found that high levels of LINC00265 expression were associated with shorter overall survival rate of patients,whereas knockdown of LINC00265 inhibited proliferation of cancer cell lines and tumor growth in xenografts.Western blot andflow cytometry analyses indicated that silencing of LINC00265 induced autophagy and apoptosis.Moreover,we showed that LINC00265 interacted with and stabilized the transcriptional co-repressor Switch-independent 3a(SIN3A),which is a scaffold protein functioning either as a tumor repressor or as an oncogene in a context-dependent manner.Silencing of SIN3A also reduced proliferation of lung cancer cells,which was correlated with the induction of autophagy.These observations raise the possibility that LINC00265 functions to promote the oncogenic activity of SIN3A in lung adenocarcinoma.Conclusions:Ourfindings thus identify SIN3A as a LINC00265-associated protein and should help to understand the mechanism underlying LINC00265-mediated oncogenesis.

日语授受表达“Vてあげる”“Vてさしあげる”的情境化研究——以日语教材中的例句为中心

本研究聚焦于日语教学中“Vてあげる”和“Vてさしあげる”的实际运用问题,通过对日语教材中例句的具体情境分析,揭示了教材提供的例句过于抽象,缺乏真实交流场景下的应用练习等问题。研究表明,为提高学习者的实际运用能力,教材设计应更多考虑语言使用的实际场景,教师在教学过程中也应引导学生理解并模仿合适的情境中的语法运用。这一发现对于日语教材编写和教学方法的改进提供了重要参考,有助于提升学习者的交际能力。

法尼醇X受体激动剂对非酒精性脂肪性肝炎治疗作用研究进展

代谢相关脂肪性肝病(metabolic dysfunction-associated fatty liver disease,MAFLD)的全球患病率为20%~40%,伴随着沉重的疾病负担和晚期疾病相关的高病死率,目前尚无批准治疗MAFLD的标准药物。法尼醇X受体(farnesoid X receptor,FXR)具有调控糖脂代谢和改善胰岛素抵抗的作用,其中奥贝胆酸作为FXR激动剂,已被多项研究证实可改善MAFLD患者的肝组织学特征。本文主要阐述FXR激动剂的作用机制和研究现状以供临床参考。

Up-to-date meta-analysis of long-term evaluations of mesenchymal stem cell therapy for complex perianal fistula

BACKGROUND Local mesenchymal stem cell(MSC)therapy for complex perianal fistulas(PFs)has shown considerable promise.But,the long-term safety and efficacy of MSC therapy in complex PFs remain unknown.AIM To explore the long-term effectiveness and safety of local MSC therapy for complex PFs.METHODS Sources included the PubMed,EMBASE,and Cochrane Library databases.A standard meta-analysis was performed using RevMan 5.3.RESULTS After screening,6 studies met the inclusion criteria.MSC therapy was associated with an improved long-term healing rate(HR)compared with the control condition[odds ratio(OR)=2.13;95%confidence interval(95%CI):1.34 to 3.38;P=0.001].Compared with fibrin glue(FG)therapy alone,MSC plus FG therapy was associated with an improved long-term HR(OR=2.30;95%CI:1.21 to 4.36;P=0.01).When magnetic resonance imaging was used to evaluate fistula healing,MSC therapy was found to achieve a higher long-term HR than the control treatment(OR=2.79;95%CI:1.37 to 5.67;P=0.005).There were no significant differences in long-term safety(OR=0.77;95%CI:0.27 to 2.24;P=0.64).CONCLUSION Our study indicated that local MSC therapy promotes long-term and sustained healing of complex PFs and that this method is safe.

Numerical simulation of the sensor output on Macao Science Satellite-1

Macao Science Satellite-1(MSS-1)will be launched at the early of 2023 into a near-circular orbit.The mission is designed to measure the Earth’s geomagnetic field with unpreceded accuracy through a new perspective.The most important component installed on the satellite,to ensure high accuracy,is the deployable boom(Optical Bench).A Vector Field Magnetometer(VFM),an Advanced Stellar Compass(ASC),and a Couple Dark State Magnetometers(CDSM)are deployed on the deployable boom.In order to maximize the mission’s scientific output,a numerical simulator on MSS-1’s deployable boom was required to evaluate the adaptability of all devices on the deployable boom and assist the satellite’s data pre-processing.This paper first briefly describes the synthesis of the Earth’s total magnetic field and then describes the method simulating the output of scalar and vector magnetometers.Finally,the calibration method is applied to the synthetic magnetometer data to analyze the possible noise/error of the relevant instruments.Our results show that the simulator can imitate the disturbance of different noise sources or errors in the measuring system,and is especially useful for the satellite’s data processing group.

Study on the deactivation and regeneration of the ZSM-5 catalyst used in methanol to olefins

ZSM-5 zeolite catalyst modified by a trace of metal cations shows high activity and high selectivity for the reaction of methanol to olefins （MTO）, but it inclines to deactivate during the reaction. In this paper, the mechanism of the catalyst deactivation and the regeneration method were studied by X-ray diffraction （XRD）, N2 adsorption-desorption, infrared spectra （IR）, and infrared spectra coupled with NH3 molecular probes （IR-NH3）. These characterizations indicated that coke formation was the main reason for the catalyst deactivation. To regenerate the deactivated catalyst, two methods, i.e., calcination and methanol leaching, were used. N2 adsorption-desorption, IR and IR-NH3 characteriza-tions showed that both methods can eliminate coke deposited on the catalyst and make the catalyst reactivated. XRD showed that the structure of the catalyst did not change after regeneration. Interestingly, the regenerated catalyst even showed better catalytic performance of the MTO reaction than the fresh one. Besides, the calcination regeneration can eliminate coke more completely, however, the methanol leaching method can be more easily carried out in situ in the reactor.

A Physical Layer Algorithm for Estimation of Number of Tags in UHF RFID Anti-Collision Design

A priori knowledge of the number of tags is crucial for anti-collision protocols in slotted UHF RFID systems.The number of tags is used to decide optimal frame length in dynamic frame slotted ALOHA(DFSA)and to adjust access probability in random access protocols.Conventional researches estimate the number of tags in MAC layer based on statistics of empty slots,collided slots and successful slots.Usually,a collision detection algorithm is employed to determine types of time slots.Only three types are distinguished because of lack of ability to detect the number of tags in single time slot.In this paper,a physical layer algorithm is proposed to detect the number of tags in a collided slot.Mean shift algorithm is utilized,and some properties of backscatter signals are investigated.Simulation results verify the effectiveness of the proposed solution in terms of low estimation error with a high SNR range,outperforming the existing MAC layer approaches.

基于静电耦合的PZT/BTO多层异质薄膜介电增强研究

采用溶胶凝胶法制备了PbZr(0.52)Ti_(0.45)O_(3)/BaTiO_(3)(PZT/BTO)多层异质薄膜,讨论了保持总厚度相同的情况下,不同周期厚度对多层异质薄膜的铁电和介电性能的影响。研究表明,随着周期厚度的减薄,层数的增加,层间的晶格失配能有效改善薄膜的结晶度,促使薄膜形貌更加平整和均匀,并且有相对较低的损耗和漏电流密度。此外,由于层间极化失配产生的层间静电耦合效应,以及空间电荷极化的存在,PZT/BTO异质薄膜的介电、铁电性能随着周期厚度的减小有着显著的提高。在周期厚度减小到55 nm时,100 k Hz测试频率下,介电常数高达293,品质因数Q为447,并表现出最优的铁电性能。

显隐性危险源场景下驾驶员避险能力评价研究

为研究显隐性危险源场景下驾驶员避险能力的差异性,借鉴中国交通事故深度调查数据库中的事故场景,利用Prescan软件构建测试场景并招募驾驶员进行避险能力驾驶模拟实验.采集7种驾驶参数数据用于表征驾驶员的避险能力,利用主成分分析法对参数进行降维,并用Ward法系统聚类对降维后得到的主成分因子进行聚类,实现对显隐性危险源场景下驾驶员避险行为的特征提取和避险能力的评价建议.

A Cross Layer Protocol for Fast Identification of Blocked Tags in Large-Scale RFID Systems

Blocker tag attack is one of the denial-of-service(DoS)attacks that threatens the privacy and security of RFID systems.The attacker interferes with the blocked tag by simulating a fake tag with the same ID,thus causing a collision of message replies.In many practical scenarios,the number of blocked tags may vary,or even be small.For example,the attacker may only block the important customers or high-value items.To avoid the disclosure of privacy and economic losses,it is of great importance to fast pinpoint these blocked ones.However,existing works do not take into account the impact of the number of blocked tags on the execution time and suffer from incomplete identification of blocked tags,long identification time or privacy leakage.To overcome these limits,we propose a cross layer blocked tag identification protocol(CLBI).CLBI consists of multiple rounds,in which it enables multiple unblocked tags to select one time slot and concurrently verify them by using tag estimation in physical layer.Benefiting from the utilization of most collision slots,the execution time can be greatly reduced.Furthermore,for efficient identification of blocked tags under different proportions,we propose a hybrid protocol named adaptive cross layer blocked tag identification protocol(A-CLBI),which estimates the remaining blocked tag in each round and adjusts the identification strategy accordingly.Extensive simulations show that our protocol outperforms state-of-the-art blocked tags identification protocol.

Endovascular stent-graft treatment for aortoesophageal fistula induced by an esophageal fishbone:Two cases report

BACKGROUND Aortoesophageal fistula(AEF)induced by esophageal fishbones is a rare complication of esophageal foreign bodies and is very difficult to treat.Although the current view suggests that endovascular stent-graft treatment is useful for AEF,whether a subsequent thoracic operation is necessary remains controversial.The purpose of this report is to describe our experience using endovascular stentgraft treatment without combined thoracic operations for the treatment of AEF in two specific cases.CASE SUMMARY We presented two cases of patients complaining of retrosternal discomfort treated in our department for an aortoesophageal fistula caused by the accidental ingestion of a fishbone.The two patients were effectively managed with combined means of endoscopic,medical(broad-spectrum antibiotic therapy,fasting,gastrointestinal decompression,etc.)and endovascular stent-graft treatment.The main difference in treatment was that the first patient presented with hematemesis after endoscopic removal of the fishbone.Subsequently,the patient underwent endovascular stent-graft treatment.The second case was managed with endoscopic removal of the fishbone with simultaneous endovascular stent-graft treatment,without any signs of hematemesis or melena.Both patients had successful postoperative management and were discharged home.Long-term follow-up is ongoing.CONCLUSION The treatment decision-making process should depend on the patients’specific situations.Our practice indicates that endovascular stent-graft treatment without combined thoracic operations could be a valuable alternative in selected patients.

Effect on changes of blood coagulation function, cytokines and immune function in patients undergoing laparoscopic radical gastrectomy for gastric cancer

Objective:To explore the changes of coagulation function, cytokines and T lymphocyte in patients undergoing laparoscopic radical gastrectomy for gastric cancer and its clinical significance.Methods: 40 cases of laparoscopic radical gastrectomy for gastric cancer patients and 40 cases of open radical gastrectomy for gastric cancer patients in our hospital were selected to detect and investigate the perioperative coagulation function [APTT (activated partial thromboplastin time), FIB (fibrinogen), and PLT (platelet)], cytokines [CRP (C reactive protein), IL-6 (IL-6) and TNF-alpha (Tumor necrosis factor-alpha)] and T lymphocytes (CD4+, CD8+ and CD4+/CD8+) changes and clinical meaning of patients in the two groups.Results: The coagulation function related indicators, cytokines and T lymphocytes of the two groups before treatment did not change significantly (P>0.05). 1 d after operation, blood coagulation, TNF-alpha, CD4+ and CD4+/CD8+ levels were significantly lower than that before operation in two groups of patients (P<0.05), while IL-6, CRP and CD8+ were significantly higher than that before the operation (P<0.05), and the index change in open group was more obvious. 3 d after surgery, the APTT, IL-6, CRP, CD4+, CD8+ and PLT levels in two group patients were significantly lower than that 1 d after surgery, while FIB, TNF-alpha and CD4+/CD8+ were significantly higher than that 1 d after surgery;blood coagulation index, TNF-alpha and CD4+ and CD4+/CD8+ were significantly lower in the laparotomy group patients than in laparoscopic group, while IL-6, CRP and CD8+ were significantly higher than the laparoscopic group (P<0.05). 5 d after operation, the APTT, TNF-alpha, FIB, CD4+, CD4+/CD8+ and PLT in two groups were significantly higher than that 3 d after surgery (P<0.05), while IL-6, CRP and CD8+ levels were significantly lower than that of 3 d after surgery (P<0.05);blood coagulation index, TNF-alpha and CD4+ and CD4+/CD8+ in the laparotomy group patients were significantly lower than laparoscopic group (P<0.05), while IL-6, CRP and CD8+ were significantly higher than the laparoscopic group (P<0.05).Conclusions: Radical resection of gastric cancer can cause coagulation disorder, inhibit the immune function and inflammatory reaction, and gradually recover with the passage of time;Compared with open surgery, laparoscopic radical gastrectomy have smaller impact on patients and recovery faster.

acSB:Anti-Collision Selective-Based Broadcast Protocol in CRAdHocs

As a fundamental operation in ad hoc networks,broadcast could achieve efficient message propagations.Particularl y in the cognitive radio ad hoc network where unlicensed users have different sets of available channels,broadcasts are carried out on multiple channels.Accordingly,channel selection and collision avoidance are challenging issues to balance the efficiency against the reliability of broadcasting.In this paper,an anticollision selective broadcast protocol,called acSB,is proposed.A channel selection algorithm based on limited neighbor information is considered to maximize success rates of transmissions once the sender and receiver have the same channel.Moreover,an anticollision scheme is adopted to avoid simultaneous rebroadcasts.Consequently,the proposed broadcast acSB outperforms other approaches in terms of smaller transmission delay,higher message reach rate and fewer broadcast collisions evaluated by simulations under different scenarios.

A new species of Occidozyga Kuhl and van Hasselt,1822(Anura:Dicroglossidae)from Southern Guangxi,China

A new species of the genus Occidozyga is reported from Southern Guangxi,China,based on morphological characters and molecular analyses.Morphological data revealed that the new species,Occidozyga shiwandashanensis sp.nov.,differs from its congeners by a combination of the following characters:(1)medium body size(SVL 25.2−33.8 mm in males,34.9−38.9 mm in females);(2)pale brown dorsum with irregular pale dark spots,especially on head;(3)creamy white ventral surface with brown spots on lateral margin and throat;(4)tongue fleshy,rounded,without notch,(5)tympanum hidden;(6)finger webbing absent and toe webbing full,but fourth toe not webbed to discs;(7)tips of fingers pointed,tips of toes rounded,slightly expanded into disc.The new species occurs on Mt.Shiwandashan and inhabits montane evergreen forests at 500−600 m a.s.l.

Epidemiological analysis on the incidence of thalassemia and G6PD deficiency in the population of childbearing age in Hengxian county in Guangxi

Objective:We investigated the incidence of thalassemia and glucose-6-phosphate dehydrogenase(G6PD)deficiency in people of childbearing age of Hengxian in Guangxi,to further provide scientific data for the diagnosis,treatment and prepotency consultation for thalassemia.Methods:A total of 12,489subjects at childbearing age who were undergoing a routine prenatal check-up in Hengxian family planning service stations were recruited in this study between January 2014and December 2014.They were screened for thalassemia by mean corpuscular volume(MCV)and mean corpuscular hemoglobin(MCH).The people with positive results then underwent thalassemia gene test.The G6PD activities were measured by enzyme kinetic method.Results:The incidence of thalassemia was 20.26%(2,530/12,489)in Hengxian,among which the incidences ofα-thalassemia,β-thalassemia,andα-thalassemia co-inheritance ofβ-thalassemia were13.20%,6.13%and 0.93%respectively.The incidence of G6PD deficiency was 5.39%(617/12,489),and the ratio between male and female is 4.27∶1.25types ofα-thalassemia genotype and 8types ofβ-thalassemia genotype were identified.The genotypes ofSEA/ααand the genotypes of41-42Mβ/Nβwere the most common genetic types forα-thalassemia andβ-thalassemia respectively.Conclusion:Hengxian is a high prevalence area of thalassemia and G6PD deficiency.SEAmutation type is the most common type inα-thalassemia,and the CD 41-42mutation is the most common type inβ-thalassemia in Hengxian.

终轧温度对低屈强比桥梁耐候钢组织及力学性能的影响

采用Gleeble-3800热模拟试验机、拉伸试验机、显微硬度计等设备,并结合光学显微镜(OM)和电子背散射衍射(EBSD)等表征方法,研究了终轧温度对Cu-Cr-Ni低屈强比桥梁耐候钢组织和力学性能的影响,并阐明了其具体的变化机理。结果表明,终轧温度880℃下的Cu-Cr-Ni桥梁耐候钢组织为粒状贝氏体,随着终轧温度由880℃降低至800℃,组织中出现针状铁素体并逐渐增多;M/A岛的平均尺寸由1.3μm增大至3.3μm,且面积分数由21.7%增大至32.3%;基体中的位错密度显著升高,主要是由基体回复程度大幅降低导致的。此外,Cu-Cr-Ni桥梁耐候钢的硬度及屈服强度随着终轧温度的降低而有所升高,屈服强度由435 MPa增大至496 MPa,抗拉强度基本不变,约为710 MPa,这是由显微组织中的针状铁素体、M/A组元和位错密度等因素共同决定。屈强比增大但总体低于0.7,塑性略有提高。

MAFLD相关肝硬化门静脉血栓形成的临床特征及危险因素分析

目的分析代谢相关脂肪性肝病(MAFLD)相关肝硬化门静脉血栓(PVT)形成的临床特征及相关危险因素。方法回顾性分析该院收治的120例MAFLD相关肝硬化患者的临床资料,其中发生PVT患者33例为PVT组,未发生PVT患者87例为非PVT组。收集患者人口学资料、既往史、并发症、实验室指标、影像学指标等,计算Child-Pugh评分,多因素logistic回归分析MAFLD相关肝硬化PVT形成的独立危险因素。结果两组年龄,性别、吸烟史、饮酒史,合并高血压、糖尿病,并发腹水、肝性脑病、自发性腹膜炎,内镜下治疗史、Child-Pugh分级比例比较差异均无统计学意义(P>0.05);而合并冠心病、有脾切除史,并发食管胃底静脉曲张、消化道出血及脾功能亢进比例比较差异有统计学意义(P<0.05)。两组ALT、AST、碱性磷酸酶(ALP)、γ-谷氨酰胺转肽酶(GGT)、总胆红素(TBil)、胆汁酸(TBA)、白蛋白(ALB)、尿酸(UA)、甘油三酯(TG)、WBC、PLT、凝血酶原时间(PT)、活化部分凝血活酶时间(APTT)、门静脉宽度分布比较差异有统计学意义(P<0.01),但总胆固醇(TC)、血红蛋白(Hb)、凝血酶时间(TT)、纤维蛋白原(Fib)比较差异无统计学意义(P>0.05)。高TG水平,并发脾功能亢进和食管胃底静脉曲张,有脾切除史是MAFLD相关肝硬化PVT形成的独立危险因素(OR=1.547、1.717、2.704、5.257,P=0.037、0.010、0.016、0.001)。结论MAFLD相关肝硬化患者应控制TG水平,尽量减少PVT形成;对于有食管胃底静脉曲张及脾功能亢进的MAFLD相关肝硬化患者应重点关注PVT,便于早期发现及干预,在进行脾切除术前评估时也应考虑后续PVT形成的风险。

Effects of the inlet particle spatial distribution on the performance of a gas-solid cyclone separator

The present study was aimed at the inlet particle spatial distribution of a gas-solid separator with high solid loading and investigated its effects on cyclone performance and the inner flow pattern.The flow fields of a cyclone with different rectangular particle flow areas on the inlet surface were numerically simulated using a four-way coupling method.The simulated results indicate that reducing the inlet particle flow area and lowing the inlet particle position can effectively reduce the scattered particles inside the cyclone separator and enhance the separation performance.Vertically gathering the particles to the centerline can also weaken the particle back-mixing.The particles near the roof account for the swirling particle ceiling phenomenon.The inlet particle spatial distribution affects the pressure drop mainly by affecting the gas tangential velocity in the cylinder body.Moreover,compared to the hori-zontal particle distribution on the inlet surface,the vertical particle distribution has greater effects on cyclone performance.