Coking behaviors and kinetics on HZSM-5/SAPO-34 catalysts for conversion of ethanol to propylene

The coke deposition on HZSM-5/SAPO-34 composite catalysts has been studied in the conversion of ethanol to propylene. The HZSM-5/SAPO-34 composite catalysts were synthesized by hydrothermal method（ZS-HS） and fully blending（ZS-MM）. The used catalysts were characterized by XRD, N;adsorption–desorption, TGA, TPO, elemental analysis, FTIR and XPS. The coking kinetics on both ZS-HS and ZS-MM has been investigated and their coking rate equations were obtained. The used ZS-MM catalyst had higher amount of coke and lower nC:nHthan the used ZS-HS. 90% of the coke was deposited in the micropores of ZS-HS, while almost 45% of the coke located in the micropores of ZS-MM. The coke deposited on ZS-HS catalyst was mainly graphite-like carbon species, whereas dehydrogenated coke species was the major on ZS-MM. The coking activation energy of ZS-MM was lower than that of ZS-HS, and the coking rate on ZS-MM was faster than on ZS-HS. In addition, the regeneration of ZS-MM catalyst showed that it had a good hydrothermal stability. The differences on coking behaviors on the two catalysts were due to their different acidic properties and textures.

撞击流-射流空化制备纳米级壳聚糖载药微球

以5-氟尿嘧啶(5-Fu)为模型药物、戊二醛为交联剂,采用撞击流-射流空化(IS-JC)耦合反相乳液过程制备纳米级5-Fu壳聚糖微球。考察油相种类和壳聚糖溶液流变学性质(CS-Rhep)对微粒大小、粒度分布、表面形貌和产率的影响,并利用扫描电镜、红外光谱(FT-IR)、X射线衍射(XRD)和热重分析(TGA)对微球的形貌、结构和性能进行表征。结果表明,IS-JC成功制备出粒度小、分布窄、分散性好、颗粒饱满,且表面光滑的5-Fu壳聚糖微球,其最小粒径和多分散指数分别为392.3 nm和0.535,交联固化40 min产率可达43.15%;微球大小、粒径分布、表面形貌和微粒的生成对CS-Rhep表现出较强的依赖性;与石蜡油相比,空化下棕榈油更适合作为有机分散介质。FT-IR显示,5-Fu成功包埋于微球之中;XRD显示,微球以无定形结构存在;TGA显示,微球对5-Fu的包埋降低了其热稳定性;棕榈油分子结构在IS-JC作用下未发生氧化和降解。IS-JC强化乳液交联过程可制备出粒度分布窄的纳米级壳聚糖载药微球,使其应用于纳米生物材料制备领域具有广阔的前景。

Investigation on threshold voltage of p-channel GaN MOSFETs based on p-GaN/AlGaN/GaN heterostructure

The threshold voltage(V_(th))of the p-channel metal-oxide-semiconductor field-effect transistors(MOSFETs)is investigated via Silvaco-Atlas simulations.The main factors which influence the threshold voltage of p-channel GaN MOSFETs are barrier heightΦ_(1,p),polarization charge density σ_(b),and equivalent unite capacitance C_(oc).It is found that the thinner thickness of p-GaN layer and oxide layer will acquire the more negative threshold voltage V_(th),and threshold voltage|V_(th)|increases with the reduction in p-GaN doping concentration and the work-function of gate metal.Meanwhile,the increase in gate dielectric relative permittivity may cause the increase in threshold voltage|V_(th)|.Additionally,the parameter influencing output current most is the p-GaN doping concentration,and the maximum current density is 9.5 mA/mm with p-type doping concentration of 9.5×10^(16) cm^(-3) at VGS=-12 V and VDS=-10 V.

Key Optimization Issues for Renewable Energy Systems under Carbon-Peaking and Carbon Neutrality Targets:Current States and Perspectives

1 Introduction The United States,Japan,Canada,the European Union,and other developed countries and regions have all formulated climate strategies and pledged to achieve net-zero CO_(2) emissions by 2050.China,meanwhile,has announced through the“carbon-peaking and carbon neutrality targets”in September 2020 that it aims to achieve“peak carbon use”by 2030 and“carbon neutrality”by 2060[1].According to statistical data from the International Energy Agency(IEA),Fig.1 illustrates the carbon intensity of electricity generation in various regions in the Announced Pledge Scenario(APS)from 2010 to 2040[2].One can easily observe that each region aims to accomplish a sharp decrease in the carbon intensity of electricity generation after 2020.

Composition Characteristics of Gas Hydrate Produced Gas and Pretreatment Research

To accelerate the pace of research and the use of alternative energy strategies Gas Hydrate, on the basis of previous studies, this paper analyzes the composition characteristics of Gas Hydrate produced gas. It provides technical support for our research and the use of Gas Hydrate. This eases the supply and demand of energy and reduces pollution of the atmospheric environment.

Research of Drainage Gas Recovery Technology in Gas Wells

Drainage gas recovery technology is the main method of gas recovery process in gas field, which has domestically and internationally been the main gas recovery processing measure in later stage of gas field production. In this context, produced water or condensate liquid will not be carried out of pit shaft by natural gas with the gradual drop of gas reservoir pressure and natural gas flow velocity, thus they will remain in pit shaft and form the so-called “gas well gathered liquid”. This fluid severely affects natural gas output and leads to the decline of oil field economic benefits, thus drainage gas recovery measure must be taken to increase gas well or even gas field output. It becomes the primary problem to be solved to select the best drainage gas recovery measure which can maximize gas field benefits and optimize gas well safety.

The Research about Storage and Transportation of Natural Gas Based on LNG Technology

Nowadays, we are in great lack of the technology theory for the storage and transportation of gas hydrate. Under this condition, after checking out related theory of these, we established the technology roadmap of the storage and transportation of gas hydrate by LNG technology. Study has shown that the technology of LNG is more saving than that of pipeline. Then we came out with the new idea of storage and transportation of hydrate by LNG technology.

Lignin-based electrospun nanofiber membrane decorated with photo-Fenton Ag@MIF-100(Fe) heterojunctions for complex wastewater remediation

Membrane technology for wastewater remediation has aroused wide interest owing to its unique properties and potential applications.However,it remains challenging to explore green,efficient and robust membrane material and technique for complex wastewater treatment.Herein,we proposed using a simple electrospinning and in situ seeding method to fabricate a lignin-based electrospun nanofiber membrane(LENM)decorated with photo-Fenton Ag@MIL-100(Fe)heterojunctions for efficient separation of oil/water emulsions and degradation of organic dye.Thanks to the embedded lignin in LENM,an ultrahigh MIL-100(Fe)loading(53 wt%)with good wettability and high porosity was obtained.As a result,the hybrid Ag@MIL-100(Fe)/LENM exhibited excellent oil/water emulsions separation efficiency(more than 97%)without a compromise of water flux.Moreover,the hybrid membrane showed an excellent dye removal with degradation of 99%methylene blue within 30 min under illumination,which is attributed to a synergy of dye adsorption/enrichment and photo-Fenton catalytic degradation from Ag@MIL-100(Fe).Therefore,the lignin-based photo-Fenton hybrid membrane can lay the foundation for the preparation and application of green,sustainable and versatile membrane materials and technologies for efficient complex wastewater remediation.

Self-assembled Conformations of a Core-shell Comb-like Chain with Adjustable Architectural Parameters

Combining Brownian dynamics simulations and self-consistent field theory,we demonstrate that the architectural parameters of coreshell comb-like chains have a decisive influence on their final self-assembled conformations.When the ratio of hydrophilic and hydrophobic segments is N_(g,g)∶N_(g,r)=3∶1,no core-shell structure is observed,and unsegregated chains or clusters are substituted.When N_(g,g)∶N_(g,r)=3∶2or 3∶3,the core-shell comb-like chains can be assembled into single micelles or structures where several small micelles are strung together by the backbone,which is similar to the pearl-necklace structure formed by the polyelectrolytes in poor solvent.With the increase of backbone length or grafting density,the probability of forming single micelles becomes lower,but the structures of two,three or more small micelles strung together are more observed.Our results indicate how to obtain the desired self-assembled structures of core-shell comb-like chains by regulating the architectural parameters,which could provide insights for the optimization of molecular design in various applications.

Hepatoblastoma with neonatal necrotizing enterocolitis:Two case reports

We report two children with hepatoblastoma(HB)with a history of neonatal necrotizing enterocolitis(NEC).Case 1 was diagnosed with HB at 5 months of age.Liver enlargement was found during the NEC operation at 3 months of age and then was clinically diagnosed by imaging.After six chemotherapy courses,a partial hepatectomy was performed.Three months after ceasing the chemotherapy,a chest computed tomography scan suggested that distant metastasis of the tumor should be considered,and the lesion was removed.However,9 months after the operation,alpha-fetoprotein concentrations were increased,and abdominal imaging showed a recurrence of the tumor in situ,resulting in a hepatectomy.Case 2 was diagnosed with NEC shortly after birth and underwent an intestinal resection and anastomosis 1 month later.He was diagnosed with HB at 3 years of age.Hepatectomy was performed after five courses of chemotherapy.Chemotherapy was stopped after 10 courses,and alpha-fetoprotein concentrations were normal.At present,both children have survived and are in a healthy condition.Physicians should be aware of the possibility of HB and a history of NEC in children.Premature birth and low birth weight are common factors leading to the pathogenesis of HB and NEC.The association between these two diseases requires further study。

Clinical characteristics of malignant germ cell tumors in adolescents:A multicenter 10-year retrospective study in Beijing

Background:The aim of this study was to review clinical features of adolescent malignant germ cell tumors(MGCTs)in Beijing and analyze the peculiar characteristics of this age group.Methods:Clinical characteristics,pathological presentations,and survival outcomes of 34 patients were analyzed retrospectively.Results:Of 34 patients,12 girls and 22 boys,18(52.9%)had an extra-cranial tumor,including one testicular tumor,five ovarian tumors,one sacrococcygeal tumor,and 11 mediastinal tumors.Histologically,we found immature teratomas(n=6),yolk sac tumors(n=5),mixed malignant tumors(n=5),an embryonic carcinoma(n=1),and seminoma(n=1).Three-year event-free survival(EFS)and overall survival(OS)were 48.8%and 62.9%,respectively.Another 16(47.1%)patients had an intracranial tumor,including nine in the pineal region,five in the suprasellar region,one in basal ganglia,and one in cerebellopontine.All patients had localized disease and an excellent outcome with 3-year EFS and OS of 93.7%and 100%,respectively.Conclusions:Adolescent MGCTs are rare with a strong dependence on gender,and the mediastina and pineal region are the most common tumor locations.The prognosis is promising compared with that of other adolescent tumors and MGCTs in other age groups.MGCTs in mediastina have a tendency to companion with other hematological malignancies,and the prognosis is extremely poor in these patients.

Particle implantation combined with chemotherapy for rhabdomyosarcoma of the head and neck:A 8-year long-term follow-up case report

Rhabdomyosarcomas(RMSs)are highly malignant soft-tissue sarcomas.Head and neck RMSs often pose unique challenges to treatment because of their closeness to important structures.We here report a rare case of a 1-year-old boy with a 1-month history of right eye swelling and an eye mass.Biopsy of deep tumors in the maxillofacial region supports embryonal RMS.Postoperative positron emission computed tomography showed a 5.0 cm×4.8 cm×4.2 cm malignant tumor in the right maxillary region.In accordance with the international RMS study group guideline,the child was diagnosed with IIIa and TNM stage T2bN1M1 embryonal RMS.The child was treated with a combination of chemotherapy and ^(125)I seed implantation radiotherapy and eventually achieved partial remission.This case report shows that ^(125)I seed implantation is a safe and effective means of delivering radiotherapy to young children with head and neck RMSs.It may be an option for children with RMSs for whom surgery or external radiotherapy is unsuitable.

Flexible N-Doped reduced graphene oxide/carbon Nanotube-MnO_(2) film as a Multifunctional Material for High-Performance supercapacitors, catalysts and sensors

A flexible 3D N-doped reduced graphene oxide(N-RGO)/carbon nanotube(CNT)eMnO_(2) hybrid film was constructed with outstanding supercapacitor,excellent oxygen reduction reaction(ORR)and good sensing performances.The resultant hybrid film possessed large specific capacitances of 418 F g^(-1) and 209 mF cm^(-2) in aqueous and solid electrolytes,and outstanding capacitance retentions of 95% and 94% were obtained for both electrolytes after experiencing 5000 cycles.A simple supercapacitor based on the resultant flexible hybrid film was further fabricated with a much smaller time constant τ0(0.38 s)than that of typical activated-carbon supercapacitors,suggesting a quick response frequency.Moreover,the assembled supercapacitor device showed high energy densities of 45.72 and 92.13 Wh kg^(-1) and simultaneously sustained large power densities of 12,526 and 15873 W kg^(-1) under a scan rate of 50 mV s^(-1) in aqueous and solid electrolytes,respectively.Furthermore,the resultant flexible film showed excellent performance in the ORR and can also be used to assemble a strain sensor with an excellent sensing performance for bending strain.

Serum Interleukin-6 Level and the rs1800795 Polymorphism in its Gene Associated with Neuroblastoma Risk in Chinese Children

Background：The pro-inflammatory cytokine,interleukin-6 （IL-6）,stimulates the metastasis of several neoplasms.An association of its serum level and the single nucleotide polymorphism （SNP） rs1800795 with neuroblastoma （NB） has been reported in American and Italian cohorts.This study was to clarify whether the same association exists in Chinese children.Methods：A total of 130 NB patients,with 77 boys （59％）,53 girls （41％）,mean age 41 ± 5 months,were assigned to two groups：high risk （HR） versus intermediate-low risk （non-HR）,and 50 healthy children were randomly selected as the age-and gender-matched controls.Peripheral blood samples were analyzed to determine serum IL-6 level using enzyme linked immunosorbent assay and rs1800795 SNPs phenotype using polymerase chain reaction and gene sequencing.Results：There were 87 NB patients in the HR group and 43 NB patients in the non-HR group.A comparison of allele and genotype frequencies of the rs1800795 polymorphism between patients and controls found no association with NB risk （P ＞ 0.05）.The frequency of GG＋GC genotype was higher in HR-NB patients than in non-HR-NB patients （64.4％ vs.48.8％,P =0.02）,and serum IL-6 level was much higher in HR-NB patients with GG＋GC genotype than in HR-NB patients with CC genotype （4.36 ± 1.1 pg/ml vs.1.83 ± 0.5 pg/ml;P =0.02）,but not in Non-HR-NB patients.Conclusions：The polymorphism rs1800795 is associated with serum IL-6 level and level of NB risk.GG genotype might indicate that the tumor is highly malignant （prone to metastasis） and associated with poor prognosis.

Effect of pravastatin on endothelial dysfunction in children with medium to giant coronary aneurysms due to Kawasaki disease

Background:Ongoing low-grade inflammation and endothelial dysfunction persist in children with coronary lesions diagnosed with Kawasaki disease(KD).Statins,frequently used in the management of high cholesterol,have also shown to improve surrogate markers of infl ammation and endothelial dysfunction.This study was undertaken to investigate the effi cacy and safety of pravastatin in children with coronary artery aneurysms due to KD.Methods:The study enrolled 14 healthy children and 13 male children,aged 2-10 years,with medium-to-giant coronary aneurysms for at least 12 months after the onset of KD.Pravastatin was given orally to the KD group at a dose of 5 mg/day for children under 5 and 10 mg/day for children older than 5 years.To determine the effects of pravastatin on endothelial function,high-frequency ultrasound was performed before the start of the study and 6 months after pravastatin therapy.The parameters measured were brachial artery flow-mediated dilation(FMD),non-flow mediated dilation(NMD),and carotid artery stiffness index(SI).High sensitive C-reactive protein(hs-CRP)levels,the circulating endothelial progenitor cells(EPCs)number,and serum lipid profiles were also determined at baseline and after 6 months of pravastatin treatment.Results:Before treatment,the KD group had significantly decreased FMD(P<0.05)and increased SI and hs-CRP levels(P<0.05)compared with controls.After 6 months of pravastatin therapy,FMD improved significantly compared to the baseline KD group(3.16±6.49 to 10.05±7.74,P<0.05),but remained significantly less than that in the control group with no signifi cant changes in NMD and SI.There were signifi cant decreases in markers of inflammation after treatment.The hs-CRP levels decreased signifi cantly from 2.93±0.81 mmol/L to 2.14±0.82 mmol/L(P<0.05)and the serum apo-B and apo-B/apo-A1 ratio were also reduced(P<0.05)in the KD group.However,the circulating EPC number was not signifi cantly different between baseline and that following pravastatin treatment in the KD group and the control group(P>0.05).No signifi cant complications were noted with paravastatin therapy.Conclusions:Pravastatin improves endothelial function and reduces low-grade chronic infl ammation in patients with coronary aneurysms due to KD.Children with coronary aneurysms due to KD may benefit from statin therapy.

Deep Learning for Visual SLAM in Transportation Robotics:A review

Visual SLAM(Simultaneously Localization and Mapping)is a solution to achieve localization and mapping of robots simultaneously.Significant achievements have been made during the past decades,geography-based methods are becoming more and more successful in dealing with static environments.However,they still cannot handle a challenging environment.With the great achievements of deep learning methods in the field of computer vision,there is a trend of applying deep learning methods to visual SLAM.In this paper,the latest research progress of deep learning applied to the field of visual SLAM is reviewed.The outstanding research results of deep learning visual odometry and deep learning loop closure detect are summarized.Finally,future development directions of visual SLAM based on deep learning is prospected.

Molded fiber and pulp products as green and sustainable alternatives to plastics:A mini review

There are significant incentives/pressures on decreasing the use of plastics and their related prod-ucts in the packaging industry,correspondingly,strong demands are emerging for clean,renew-able,recyclable/biodegradable packaging products.In this context,molded fiber/pulp products have attracted increasing attention,due to their green/sustainable advantages,simply because the raw materials used are plant-based and/or recycled fibers.Many companies have switched their packing practices from plastics to more environmentally friendly products,such as molded fiber products,which already have had and will continue to have obvious effect on packaging industries.This paper initially provides an overview on the general concept of molded pulp prod-ucts,and further summarizes the different types of molded fiber products in terms of natural fiber sources,manufacturing processes,current and emerging applications as well as the environmental sustainability of molded products.

Distributionally Robust Optimal Reactive Power Dispatch with Wasserstein Distance in Active Distribution Network

The uncertainties from renewable energy sources(RESs)will not only introduce significant influences to active power dispatch,but also bring great challenges to the analysis of optimal reactive power dispatch(ORPD).To address the influence of high penetration of RES integrated into active distribution networks,a distributionally robust chance constraint(DRCC)-based ORPD model considering discrete reactive power compensators is proposed in this paper.The proposed ORPD model combines a second-order cone programming(SOCP)-based model at the nominal operation mode and a linear power flow(LPF)model to reflect the system response under certainties.Then,a distributionally robust optimization(WDRO)method with Wasserstein distance is utilized to solve the proposed DRCC-based ORPD model.The WDRO method is data-driven due to the reason that the ambiguity set is constructed by the available historical data without any assumption on the specific probability distribution of the uncertainties.And the more data is available,the smaller the ambiguity would be.Numerical results on IEEE 30-bus and 123-bus systems and comparisons with the other three-benchmark approaches demonstrate the accuracy and effectiveness of the proposed model and method.

YB1 regulates miR-205/200b-ZEB1 axis by inhibiting microRNA maturation in hepatocellular carcinoma

Background:Y-box binding protein 1(YB1 or YBX1)plays a critical role in tumorigenesis and cancer progression.However,whether YB1 affects malignant transformation by modulating non-codingRNAs remains largely unknown.This study aimed to investigate the relationship between YB1 and microRNAs and reveal the underlying mechanism by which YB1 impacts on tumor malignancy via miRNAs-mediated regulatory network.Methods:The biological functions of YB1 in hepatocellular carcinoma(HCC)cells were investigated by cell proliferation,wound healing,and transwell invasion assays.The miRNAs dysregulated by YB1 were screened by microarray analysis in HCC cell lines.The regulation of YB1 on miR-205 and miR-200b was determined by quantitative real-time PCR,dual-luciferase reporter assay,RNA immunoprecipitation,and pull-down assay.The relationships of YB1,DGCR8,Dicer,TUT4,and TUT1 were identified by pull-down and coimmunoprecipitation experiments.The cellular co-localization of YB1,DGCR8,and Dicer were detected by immunofluorescent staining.The in vivo effect of YB1 on tumor metastasis was determined by injecting MHCC97H cells transduced with YB1 shRNA or shControl via the tail vein in nude BALB/c mice.The expression levels of epithelial tomesenchymal transition markerswere detected by immunoblotting and immunohistochemistry assays.Results:YB1 promoted HCC cell migration and tumor metastasis by regulating miR-205/200b‒ZEB1 axis partially in a Snail-independent manner.YB1 suppressedmiR-205 and miR-200b maturation by interacting with the microprocessors DGCR8 and Dicer as well as TUT4 and TUT1 via the conserved cold shock domain.Subsequently,the downregulation of miR-205 and miR-200b enhanced ZEB1 expression,thus leading to increased cell migration and invasion.Furthermore,statistical analyses on gene expression data from HCC and normal liver tissues showed that YB1 expression was positively associated with ZEB1 expression and remarkably correlated with clinical prognosis.Conclusion:This study reveals a previously undescribed mechanism by which YB1 promotes cancer progression by regulating the miR-205/200b‒ZEB1 axis in HCC cells.Furthermore,these results highlight that YB1 may play biological functions via miRNAs-mediated gene regulation,and it can serve as a potential therapeutic target in human cancers.

Chitosan as A Preservative for Fruits and Vegetables:A Review on Chemistry and Antimicrobial Properties

Chitosan,derived from chitin,a major constituent(in quantity)of crustaceans,is a unique aminopolysaccharide with emerging commercial potential in agriculture,food,pharmaceuticals and nutraceuticals due to its nontoxic,biodegradable and biocompatable properties.Chitosan coating on fruits and vegetables has been found to be effective for the reduction of a variety of harmful micro-organims and extend the shelf-life of these products.In this review,our focus is on the antimicrobial properties of chitosan and its application as a natural preservative for fresh products.We detailed the key properties that are related to food preservation,the molecular mechanism of the antimicrobial activity of chitosan on fungi,gram-positive and gram-negative bacteria,coating methods for using chitosan and its formulation for preserving fruits and vegetables,as well as the radiation method of producing chitosan from chitin.Understanding the economic and scientific factors of chitosan’s production and efficiency as a preservative will open its practical application for fruits and vegetable preservation.