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.

Apolipoprotein E4 interferes with lipid metabolism to exacerbate depression-like behaviors in 5xFAD mice

Background:Apolipoprotein E4(ApoE4)allele is the strongest genetic risk factor for late-onset Alzheimer's disease,and it can aggravate depressive symptoms in non-AD patients.However,the impact of ApoE4 on AD-associated depression-l ike behaviors and its underlying pathogenic mechanisms remain unclear.Methods:This study developed a 5xFAD mouse model overexpressing human ApoE4(E4FAD).Behavioral assessments and synaptic function tests were conducted to explore the effects of ApoE4 on cognition and depression in 5xFAD mice.Changes in peripheral and central lipid metabolism,as well as the levels of serotonin(5-HT)andγ-aminobutyric acid(GABA)neurotransmitters in the prefrontal cortex,were examined.In addition,the protein levels of 24-dehydrocholesterol reductase/glycogen synthase kinase-3 beta/mammalian target of rapamycin(DHCR24/GSK3β/m TOR)and postsynaptic density protein 95/calmodulin-dependent protein kinase II/brain-derived neurotrophic factor(PSD95/CaMK-II/BDNF)were measured to investigate the molecular mechanism underlying the effects of ApoE4 on AD mice.Results:Compared with 5xFAD mice,E4FAD mice exhibited more severe depressionlike behaviors and cognitive impairments.These mice also exhibited increased amyloid-beta deposition in the hippocampus,increased astrocyte numbers,and decreased expression of depression-related neurotransmitters 5-HT and GABA in the prefrontal cortex.Furthermore,lipid metabolism disorders were observed in E4FAD,manifesting as elevated low-density lipoprotein cholesterol and reduced high-density lipoprotein cholesterol in peripheral blood,decreased cholesterol level in the prefrontal cortex,and reduced expression of key enzymes and proteins related to cholesterol synthesis and homeostasis.Abnormal expression of proteins related to the DHCR24/GSK3β/m TOR and PSD95/CaMK-II/BDNF pathways was also observed.Conclusion:This study found that ApoE4 overexpression exacerbates depressionlike behaviors in 5xFAD mice and confirmed that ApoE4 reduces cognitive function in these mice.The mechanism may involve the induction of central and peripheral lipid metabolism disorders.Therefore,modulating ApoE expression or function to restore cellular lipid homeostasis may be a promising therapeutic target for AD comorbid with depression.This study also provided a better animal model for studying AD comorbid with depression.

A class of Ga-Al-P-based compounds with disordered lattice as advanced anode materials for Li-ion batteries

Phosphides possess large reversible capacity, small voltage hysteresis, and high energy efficiency, thus promising to be new anode candidates to replace commercial graphite for Li-ion batteries(LIBs).Through a facile mechanochemistry method, we prepare a novel ternary phosphide of Ga0.5Al0.5P whose crystalline structure is determined to be a cation-disordered cubic zinc sulfide structure according to XRD refinement. As an anode for LIBs, the Ga0.5Al0.5P delivers a reversible capacity of 1,352 mA h g^(-1)at100 mA g^(-1)with an initial Coulombic efficiency(ICE) up to 90.0% based on a reversible Li-storage mechanism integrating intercalation and subsequent conversion processes as confirmed by various characterizations techniques including in-situ XRD, ex-situ Raman, and XPS and electrochemical characterizations.Graphite-modified Ga0.5Al0.5P exhibits a long-lasting cycling stability of retaining 1,182 mA h g^(-1)after300 cycles at 100 m A g^(-1), and 625 mA h g^(-1)after 800 cycles at 2,000 mA g^(-1), and a high-rate performance of remaining 342 m A h g^(-1)at 20,000 mA g^(-1). The outstanding electrochemical performances can be attributed to enhanced reaction kinetics enabled by the capacitive behaviors and the faster Liion diffusion enabled by the cation-mixing. Importantly, by tuning the cationic ratio, we develop a novel series of cation-mixed compounds of Ga_(1/3)Al_(2/3)P, Ga_(1/4)Al_(3/4)P, Ga_(1/5)Al_(4/5)P, Ga_(2/3)Al_(1/3)P, Ga_(3/4)Al_(1/4)P, and Ga_(4/5)Al_(1/5)P, which demonstrate large capacity, high ICE, and suitable anode potentials. Broadly, these compounds with disordered lattices probably present novel physicochemical properties, and high electrochemical performances, thus providing a new perspective for new materials design.

Single-Phase Ternary Compounds with a Disordered Lattice and Liquid Metal Phase for High-Performance Li-Ion Battery Anodes

Si is considered as the promising anode materials for lithium-ion batteries(LIBs)owing to their high capacities of 4200 mAh g-1and natural abundancy.However,severe electrode pulverization and poor electronic and Li-ionic conductivities hinder their practical applications.To resolve the afore-mentioned problems,we first demonstrate a cation-mixed disordered lattice and unique Li storage mechanism of single-phase ternary GaSiP_(2)compound,where the liquid metallic Ga and highly reactive P are incorporated into Si through a ball milling method.As confirmed by experimental and theoretical analyses,the introduced Ga and P enables to achieve the stronger resistance against volume variation and metallic conductivity,respectively,while the cation-mixed lattice provides the faster Li-ionic diffusion capability than those of the parent GaP and Si phases.The resulting GaSiP_(2)electrodes delivered the high specific capacity of 1615 mAh g-1and high initial Coulombic efficiency of 91%,while the graphite-modified GaSiP_(2)(GaSiP_(2)@C)achieved 83%of capacity retention after 900 cycles and high-rate capacity of 800 at 10,000 mA g-1.Furthermore,the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)//Ga SiP_(2)@C full cells achieved the high specific capacity of 1049 mAh g-1after 100 cycles,paving a way for the rational design of high-performance LIB anode materials.

Effects of Mouse Thatched on Soil Temperature, Yield and Quality in Apple Orchard

[Objectives]This study was conducted to study the effect of mouse thatched on soil temperature,yield and quality in orchards.[Methods]The response of orchard soil,yield and quality to sod culture was studied by comparisons of grassing for two years,three years and clean cultivation.[Results]In April,the soil temperature in mouse thatched area was higher than that in clean cultivation area,and the temperature in the three years of sward was the highest.From May to July,the temperature in mouse thatched area was lower than that in clean cultivation area,and the temperature was lowest in the three years of sward.At the same time,the fruit yield and quality were improved.Averaged the two years,the yield of apple increased by 12%,and the contents of sugar,soluble solids and vitamin C and the firmness of the fruit were increased,and the total acid content was decreased by planting mouse thatched.[Conclusions]Adjusting soil temperature in orchards by planting grass achieved the effects of promoting the activity of microorganisms,facilitating the growth of root system,increasing the yield and improving the quality.

Thermal Analysis by Means of Differential Scanning Calorimetry of the Characteristic Thermodynamic Temperatures of a Cu-Zr-Al Bulk Metallic Glass

In this study a Cu_(43)Zr_(48)Al_(9)bulk metallic glass prepared by the copper mold casting method is considered.In recent years,Cu-Zr-Al systems like this have enjoyed widespread attention due to their high strength,high hardness,high corrosion resistance and low cost.Here samples of this substance are studied using DSC(Differential scanning calorimetry)to determine the effect of different test conditions(heating rate,sample mass,sample specific surface area and sample crystal phase)on the characteristic thermodynamic temperature of the bulk metallic glass.Experimental results show that almost all of the five characteristic thermodynamic temperatures(T_(g),T_(x),T_(p),T_(m),T_(l))of this substance have higher values when the heating rate is increased.The influence of the variation of sample mass,sample specific surface area and sample crystal phase on the amorphous alloy characteristic temperature is very weak.lower the heating rate,the more developed the crystalline phase in the amorphous alloy will be.

Application of Enzyme Engineering in Pharmacy

Enzyme engineering is an important part of modern biotechnology.Due to its high reaction specificity,high efficiency,mild reaction conditions,and low pollution,it is also an important method widely used in the pharmaceutical field.The application of enzymes in medicine is diverse,such as:diagnosis,prevention and treatment of diseases with enzymes,manufacture of various drugs with enzymes,etc.,mainly through manual operations,to obtain enzymes required by the pharmaceutical industry,and through various means Enzymes perform their catalytic functions.This article mainly introduces the application of enzyme engineering in the pharmaceutical field,and also prospects the development trend of enzyme engineering in the pharmaceutical field.

Outcomes of early hospital readmission after kidney transplantation: Perspectives from a Canadian transplant centre

BACKGROUND Early hospital readmissions(EHRs)after kidney transplantation range in incidence from 18%-47%and are important and substantial healthcare quality indicators.EHR can adversely impact clinical outcomes such as graft function and patient mortality as well as healthcare costs.EHRs have been extensively studied in American healthcare systems,but these associations have not been explored within a Canadian setting.Due to significant differences in the delivery of healthcare and patient outcomes,results from American studies cannot be readily applicable to Canadian populations.A better understanding of EHR can facilitate improved discharge planning and long-term outpatient management post kidney transplant.AIM To explore the burden of EHR on kidney transplant recipients(KTRs)and the Canadian healthcare system in a large transplant centre.METHODS This single centre cohort study included 1564 KTRs recruited from January 1,2009 to December 31,2017,with a 1-year follow-up.We defined EHR as hospitalizations within 30 d or 90 d of transplant discharge,excluding elective procedures.Multivariable Cox and linear regression models were used to examine EHR,late hospital readmissions(defined as hospitalizations within 31-365 d for 30-d EHR and within 91-365 d for 90-d EHR),and outcomes including graft function and patient mortality.RESULTS In this study,307(22.4%)and 394(29.6%)KTRs had 30-d and 90-d EHRs,respectively.Factors such as having previous cases of rejection,being transplanted in more recent years,having a longer duration of dialysis pretransplant,and having an expanded criteria donor were associated with EHR post-transplant.The cumulative probability of death censored graft failure,as well as total graft failure,was higher among the 90-d EHR group as compared to patients with no EHR.While multivariable models found no significant association between EHR and patient mortality,patients with EHR were at an increased risk of late hospital readmissions,poorer kidney function throughout the 1st year post-transplant,and higher hospital-based care costs within the 1st year of follow-up.CONCLUSION EHRs are associated with suboptimal outcomes after kidney transplant and increased financial burden on the healthcare system.The results warrant the need for effective strategies to reduce post-transplant EHR.

m6A甲基化酶METTL3在癌症发生发展中的作用

N6-甲基腺苷(m6A)是RNA中最普遍的表观遗传修饰。甲基化酶样3(methyltransferase like 3,METTL3)作为最主要的甲基化酶,参与m6A所调节的RNA的剪接、运输、翻译和降解等生物过程。目前,诸多研究证实METTL3在人类癌症中发挥着重要作用且影响癌症进展。METTL3能够通过多种机制调控癌症的发生发展:影响癌细胞甲基化水平、mRNA稳定性、调节癌细胞转化、相关信号通路、细胞凋亡等。因此,深入研究癌症发展机制,阐明METTL3调节癌症的发病机理,对癌症诊疗具有重要的理论意义和应用价值。本文通过对METTL3在多种癌症中的调节机制进行整理和分析,并总结了METTL3在各种癌症发生和发展中的最新研究进展。

Expert consensus on dental caries management

Dental Caries is a kind of chronic oral disease that greatly threaten human being’s health.Though dentists and researchers struggled for decades to combat this oral disease,the incidence and prevalence of dental caries remain quite high.Therefore,improving the disease management is a key issue for the whole population and life cycle management of dental caries.So clinical difficulty assessment system of caries prevention and management is established based on dental caries diagnosis and classification.Dentists should perform oral examination and establish dental records at each visit.When treatment plan is made on the base of caries risk assessment and carious lesion activity,we need to work out patient-centered and personalized treatment planning to regain oral microecological balance,to control caries progression and to restore the structure and function of the carious teeth.And the follow-up visits are made based on personalized caries management.This expert consensus mainly discusses caries risk assessment,caries treatment difficulty assessment and dental caries treatment plan,which are the most important parts of caries management in the whole life cycle.

Mesoscale fracture behavior of Longmaxi outcrop shale with different bedding angles:Experimental and numerical investigations

The mechanical properties and fracturing mechanism of shale containing beddings are critically important in shale gas exploitation and wellbore stability.To investigate the effects of shale bedding on crack behavior and fracturing mechanism,scanning electron microscope(SEM)with a loading system was employed to carry out three-point bending tests on Longmaxi outcrop shale.The crack initiation and propagation of Longmaxi shale were observed and recorded by taking photos during loading.The cracking paths were extracted to calculate the crack length through a MATLAB program.The peak load,fracture toughness and fracture energy all increase with the bedding angle from 0°to 90°.The crack length and energy were also found to increase with the bedding angle in the range of 0°-600 and then drop slightly.The fracturing mechanism of shale includes the main crack affected by the bedding angle and disturbed by randomly distributed particles.The main cracking path was accompanied by several microcrack branches which could form an interconnected crack system.When the main crack encounters larger sedimentary particles,it will deflect around the particles and then restore to the initial direction.A numerical technique using extended finite element method(XFEM)coupled with anisotropic cohesive damage criteria was developed,which is able to capture the dependence of crack propagations on bedding angle and sedimentary particles.This study sheds light on understanding and predicting mesoscale fracture behavior of shale with different bedding angles.

Expert consensus on early childhood caries management

Early childhood caries(ECC)is a significant chronic disease of childhood and a rising public health burden worldwide.ECC may cause a higher risk of new caries lesions in both primary and permanent dentition,affecting lifelong oral health.The occurrence of ECC has been closely related to the core microbiome change in the oral cavity,which may be influenced by diet habits,oral health management,fluoride use,and dental manipulations.So,it is essential to improve parental oral health and awareness of health care,to establish a dental home at the early stage of childhood,and make an individualized caries management plan.Dental interventions according to the minimally invasive concept should be carried out to treat dental caries.This expert consensus mainly discusses the etiology of ECC,caries-risk assessment of children,prevention and treatment plan of ECC,aiming to achieve lifelong oral health.

Studies for Intervention and Effect Assessment on Arsenism

Chronic exposed to high arsenic via drinking water is worldwide public health problem. A large number of epidemiological studies showed that exposed to arsenic cause the human body skin lesions and also induce cancer, cardiovascular and other kind of diseases. So arsenism not only affect the person’s work capability and life quality but also result in economic losses and mental suffering. How to prevent and control the effects of high arsenic? What intervention is more important and necessary for arsenism? How to scientifically assess the interventions effect of short-term and long-term? Through a systematic follow-up investigation in different high arsenic regions in Inner Mongolia, the environmental arsenic and human body internal arsenic exposure were analyzed, the clinical characteristics and signs of arsenism patients were examined. We established the evaluation system of intervention and control measures for population exposed to high arsenic. This evaluation system and control measures included government and exposed population. For government, change water supply and keep it work well and health education is very important. For exposed population, improving the diet and treating the symptoms or signs related to arsenic is more necessary. Arsenic in human body such as nail or urine sample arsenic must be reduced to normal value and this index show that the subject if still or not expose to high arsenic.

Numerical Study on Rock Breaking Mechanism of Supercritical CO_(2)Jet Based on Smoothed Particle Hydrodynamics

Supercritical carbon dioxide(Sc-CO_(2))jet rock breaking is a nonlinear impact dynamics problem involving many factors.Considering the complexity of the physical properties of the Sc-CO_(2)jet and the mesh distortion problem in dealing with large deformation problems using the finite element method,the smoothed particle hydrodynamics(SPH)method is used to simulate and analyze the rock breaking process by Sc-CO_(2)jet based on the derivation of the jet velocity-density evolution mathematical model.The results indicate that there exists an optimal rock breaking temperature by Sc-CO_(2).The volume and length of the rock fracture increase with the rising of the jet temperature but falls when the jet temperature exceeds 340 K.With more complicated perforation shapes and larger fracture volumes,the Sc-CO_(2)jet can yield a rock breaking more effectively than water jet,The stress analysis shows that the Sc-CO_(2)rock fracturing process could be reasonably divided into three stages,namely the fracture accumulation stage,the rapid failure stage,and the breaking stabilization stage.The high diffusivity of Sc-CO_(2)is identified as the primary cause of the stress fluctuation and W-shaped fracture morphology.The simulated and calculated results are generally in conformity with the published experimental data.This study provides theoretical guidance for further study on Sc-CO_(2)fracturing mechanism and rock breaking efficiency.

Dynamic apertures with diffusion-regulatory functionality in soft porous crystals:A key to solving the century puzzle on isotopologues separation

The separation of water isotopologues has been a“century-old”challenge,also known as“the Holy Grail”in separation science.Heavy water(D2O)is a stable non-radioactive water isotopologue that plays a critical role in scientific research,military,nuclear energy,and medical fields.Heavy water was first reported in 1931 when H.C.Urey discovered D2 and D2O,for which he was awarded the Nobel Prize in Chemistry in 1934.Then in 1933,G.N.Lewis et al.obtained 0.5μL of heavy water at a concentration of around 65.7%when electrolyzing 10 liters of water.In 1935,the world's first heavy water plant was built in Norway,producing 2 tons of heavy water by electrolysis,but the separation factor was merely 1.05,which was extremely energy-consuming.In 1943,the first heavy water plant employing the distillation method was built in the United States.

Neuroprotective effect of estrogen after chronic spinal cord injury in ovariectomized rats

BACKGROUND： At present, there is still lack of effective drugs for chronic spinal cord injury, whereas it is found recently that estrogen has a neuroprotective effect on brain and spinal cord injuries. OBJECTIVE： To observe the effect of estrogen on the apoptosis of nerve cells after gradual chronic spinal cord injury in ovariectomized rats. DESIGN： A randomized controlled animal trial. SETTING： Institute of Orthopaedics, the Second Hospital of Lanzhou University. MATERIALS： Sixty-five female Wistar rats of common degree, weighing 220 - 250 g, were provided by the experimental animal center of Lanzhou University. The rats were randomly divided into sham-operated group （n =5）, estrogen-treated group （n =30） and saline control group （n =30）, and the latter two groups were observed at 1, 3, 7, 14, 28 and 60 days respectively, and 5 rats for each time point. METHODS： All the rats were treated with bilateral oophorectomy 2 weeks before the experiment. Tt0 vertebral lamina was revolved into using plastic screw. The spinal canal impingement was not induced initially. After that, the original incision was opened to expose the screw every 7 - 10 days. MAIN OUTCOME MEASURES： The apoptosis and Caspase-3 positive cells in the damaged spinal cord were detected using terminal deoxynucleotidal transferase-mediated dUTP-biotin nick end labeling （TUNEL） method and Caspase-3 immunohistochemical staining at 1, 3, 7, 14, 28 and 60 days after chronic spinal cord injury respectively. RESULTS： Totally 65 rats were used, and the deleted ones during the experiment were supplemented by others. Changes of Caspase-3 expression after spinal cord injury： In the sham-operated group, only a small amount of Caspase-3 proteins were observed in the rat spinal cord, mainly located in motor neurons of spinal cord anterior horn. In the estrogen-treated group and saline control group, positive cells expressed occasionally at 1 day postoperatively, began to increase obviously at 7 days after injury, strongly expressed at 14 and 28 days, but decreased at 60 days, mainly located in the neurons of spinal cord gray matter anterior horn, and they expressed fewer in the motor neurons and white matter of ventral horn, and there were obvious differences between the estrogen-treated group and saline control group at 7, 14, 28 and 60 days （P 〈 0.05）. CONCLUSION： Estrogen can reduce the apoptosis of nerve cells and promote the recovery of neurological function following gradual chronic soinal cord injury.

Altitudinal Variation in Digestive Tract Length in Yunnan Pond Frog (Pelophylax pleuraden)

The digestive tract plays an important role in digestion and the acquisition of food energy. Understanding the impact of abiotic environments on digestive tract morphology is especially important for evolution of digestive tract across different environments. Here, we investigated altitudinal variation in digestive tract length in the Yunnan Pond Frog （Pelophylaxpleuraden） across five populations ranging from 1413 m to 1935 m a.s.1, in Ningnan County, Sichuan province in western China. Frogs were collected during the breeding season, from 1-5 June 2012. Our results revealed that females had longer digestive tract and relative digestive tract （i.e. digestive tract length / body size） lengths in com- parison to males, on average, but the differences between them decreased with increasing altitude. Digestive tract and relative digestive tract lengths increased with increasing altitude suggesting that a higher proportion of indigestible ma- terials may be consumed at high-altitude sites and result in a relative increase in digestive tract dimensions.

A multi-kernel-shell indium selenide@carbon nanosphere enabling high-performance lithium-ion batteries

Indium selenide has garnered significant attention for high volumetric capacities,but is currently plagued by the sluggish charge transfer kinetics,severe volume effect,and rapid capacity degradation that hinder their practical applications.Herein,we design,synthesize,and characterize a multi-kernel-shell structure comprised of indium selenide encapsulated within carbon nanospheres(referred to as m-K-S In_(2)Se_(3)@C)through an integrated approach involving a hydrothermal method followed by a gaseous selenization process.Importantly,experimental measurements and density functional theory calculations confirm that the m-K-S In_(2)Se_(3)@C not only improve the adsorption capability for Li-ions but also lower the energy barrier for Li-ions diffusion.Profiting from numerous contact points,shorter diffusion distances and an improved volume buffering effect,the m-K-S In_(2)Se_(3)@C achieves an 800 mA h g^(−1)capacity over 1000 loops at 1000 mA g^(−1),a 520 mA h g^(−1)capacity at 5000 mA g^(−1)and an energy density of 270 Wh kg^(−1)when coupled with LiFePO4,surpassing most related anodes reported before.Broadly,the m-K-S structure with unique nano-micro structure offers a new approach to the design of advanced anodes for LIBs.