CFD modeling of gas−liquid flow phenomenon in lead smelting oxygen-enriched side-blown furnace

A validated numerical model was established to simulate gas−liquid flow behaviors in the oxygen-enriched side-blown bath furnace.This model included the slip velocity between phases and the gas thermal expansion effect.Its modeling results were verified with theoretical correlations and experiments,and the nozzle-eroded states in practice were also involved in the analysis.Through comparison,it is confirmed that the thermal expansion effect influences the flow pattern significantly,which may lead to the backward motion of airflow and create a potential risk to production safety.Consequently,the influences of air injection velocity and furnace width on airflow behavior were investigated to provide operating and design guidance.It is found that the thin layer melt,which avoids high-rate oxygen airflow eroding nozzles,shrinks as the injection velocity increases,but safety can be guaranteed when the velocity ranges from 175 to 275 m/s.Moreover,the isoline patterns and heights of thin layers change slightly when the furnace width increases from 2.2 to 2.8 m,indicating that the furnace width shows a limited influence on production safety.

Mechanism of inflammatory response and therapeutic effects of stem cells in ischemic stroke:current evidence and future perspectives

Ischemic stroke is a leading cause of death and disability worldwide,with an increasing trend and tendency for onset at a younger age.China,in particular,bears a high burden of stroke cases.In recent years,the inflammatory response after stroke has become a research hotspot:understanding the role of inflammatory response in tissue damage and repair following ischemic stroke is an important direction for its treatment.This review summarizes several major cells involved in the inflammatory response following ischemic stroke,including microglia,neutrophils,monocytes,lymphocytes,and astrocytes.Additionally,we have also highlighted the recent progress in various treatments for ischemic stroke,particularly in the field of stem cell therapy.Overall,understanding the complex interactions between inflammation and ischemic stroke can provide valuable insights for developing treatment strategies and improving patient outcomes.Stem cell therapy may potentially become an important component of ischemic stroke treatment.

Gas-hydrate formation,agglomeration and inhibition in oil-based drilling fluids for deep-water drilling

One of the main challenges in deep-water drilling is gas-hydrate plugs,which make the drilling unsafe.Some oil-based drilling fluids（OBDF） that would be used for deep-water drilling in the South China Sea were tested to investigate the characteristics of gas-hydrate formation,agglomeration and inhibition by an experimental system under the temperature of 4 ？C and pressure of 20 MPa,which would be similar to the case of 2000 m water depth.The results validate the hydrate shell formation model and show that the water cut can greatly influence hydrate formation and agglomeration behaviors in the OBDF.The oleophobic effect enhanced by hydrate shell formation which weakens or destroys the interfacial films effect and the hydrophilic effect are the dominant agglomeration mechanism of hydrate particles.The formation of gas hydrates in OBDF is easier and quicker than in water-based drilling fluids in deep-water conditions of low temperature and high pressure because the former is a W/O dispersive emulsion which means much more gas-water interfaces and nucleation sites than the later.Higher ethylene glycol concentrations can inhibit the formation of gas hydrates and to some extent also act as an anti-agglomerant to inhibit hydrates agglomeration in the OBDF.

Rainfall Microphysical Properties of Landfalling Typhoon Yagi(201814)Based on the Observations of Micro Rain Radar and Cloud Radar in Shandong,China

The development and evolution of precipitation microphysical parameters and the vertical structure characteristics associated with Typhoon Yagi(201814)are analyzed in the city of Jinan,Shandong Province based primarily on the observations of a micro rain radar(MRR),a cloud radar,and a disdrometer.The precipitation process is further subdivided into four types:convective,stratiform,mixed,and light precipitation according to the ground disdrometer data,which is in agreement with the vertical profile of the radar reflectivity detected by the MRR.Vertical winds may be the main source of MRR retrieval error during convective precipitation.Convective precipitation has the shortest duration but makes the largest contribution to the cumulative precipitation.Collision-coalescence is the main microphysical process of stratiform precipitation and light precipitation below the bright band observed by the MRR.It is worth noting that as Typhoon Yagi(201814)transformed into an extratropical cyclone,its raindrop size distributions no longer had the characteristics of maritime precipitation,but become more typical of the characteristic of continental precipitation,which represents a very different raindrop size distribution from that which is normally observed in a landfalling typhoon.

CFD modelling and optimization of oxygen supply mode in KIVCET smelting process

The influence of oxygen supply mode on the KIVCET (a Russian acronym for flash?cyclone?oxygen?electric?smelting) process was investigated using numerical simulation. The mass rate ratio (MRR) of central oxygen to lateral oxygen of the central jet distributor (CJD) burner was defined to express the oxygen supply mode, and the KIVCET process with an MRR ranging from 0.09 to 0.39 was simulated. The results show that there are four efficient reaction regions that correspond to four CJD burners. A higher central oxygen flow improves the mixing between particles and oxygen, thus enhancing reactions and shortening the reaction regions. However, a higher dust rate is induced due to the spread of the particle columns. The optimal MRR for a KIVCET furnace with a smelting capacity of 50000 kg/h is suggested to be 0.31. In this case, the chemical reactions associated with the feed are completed with an acceptable dust rate.

Modeling of microstructural evolution during dynamic recrystallization in coarse Nb microalloyed austenite

The aim of the current study was to investigate the microstructural evolution during dynamic recrystallization in coarse Nb microalloyed austenite in thin slab direct rolling （TSDR） processing. A model was developed to predict the change of the austenite grain size during the dynamic recrystallization, by using the law of mixtures. The equations initially developed for partial static recrystallization were used for partial dynamic recrystallization, by adjusting the value of the constant. The results show that the change of the austenite grain size can be reasonably described by using the equations developed according to the law of mixtures.

Microarray microRNA profiling of urinary exosomes in a 5XFAD mouse model of Alzheimer’s disease

Background:Alzheimer's disease(AD)is an incurable and irreversible neurodegen-erative disease,without a clear pathogenesis.Therefore,identification of candidates before amyloid-βplaque(Aβ)deposition proceeds is of major significance for earlier intervention in AD.Methods:To explore the potential noninvasive earlier biomarkers of AD in a 5XFAD mouse model,microRNAs(miRNAs)from urinary exosomes in 1-month-old pre-Aβaccumulation 5XFAD mice models and their littermate controls were profiled by mi-croarray analysis.The differentially expressed miRNAs were further analyzed via droplet digital PCR(ddPCR).Results:Microarray analysis demonstrated that 48 differentially expressed miRNAs(18 upregulated and 30 downregulated),of which six miRNAs-miR-196b-5p,miR-339-3p,miR-34a-5p,miR-376b-3p,miR-677-5p,and miR-721-were predicted to display gene targets and important signaling pathways closely associated with AD pathogenesis and verified by ddPCR.Conclusions:Urinary exosomal miRNAs showing differences in expression prior to Aβ-plaque deposition were identified.These exosomal miRNAs represent potential noninvasive biomarkers that may be used to prevent AD in clinical applications.

Investigation of working pressure on the surface roughness controlling technology of glow discharge polymer films based on the diagnosed plasma

The effects of working pressure on the component, surface morphology, surface roughness, and deposition rate of glow discharge polymer （GDP） films by a trans-2-butene/hydrogen gas mixture were investigated based on plasma characteristics diagnosis. The composition and ion energy distributions of a multi-carbon （CaHs/H2） plasma mixture at different working pressures were diagnosed by an energy-resolved mass spectrometer （MS） during the GDP film deposition process. The Fourier transform infrared spectroscopy （FT-IR）, field emission scanning electron microscope （SEM） and white-fight interferometer （WLI） results were obtained to investigate the structure, morphology and roughness characterization of the deposited films, respectively. It was found that the degree of ionization of the C4H8/H2 plasma reduces with an increase in the working pressure. At a low working pressure, the C-H fragments exhibited small-mass and high ion energy in plasma. In this case, the film had a low CH3/CH2 ratio, and displayed a smooth surface without any holes, cracks or asperities. While the working pressure increased to 15 Pa, the largest number of large-mass fragments led to the deposition rate reaching a maximum of 2.11 #m h-1, and to hole defects on the film surface. However, continuing to increase the working pressure, the film surface became smooth again, and the interface between clusters became inconspicuous without etching pits.

Correlation of Rainfall Anomalies in Rwanda from September to December (SOND) with Indian Ocean Dipole (IOD) and El Nino Southern Oscillation (ENSO) Events

Understanding the relationship between rainfall anomalies and large-scale systems is critical for driving adaptation and mitigation strategies in socioeconomic sectors. This study therefore aims primarily to investigate the correlation between rainfall anomalies in Rwanda during the months of September to December (SOND) with the occurrences of Indian Ocean Dipole (IOD) and El Nino Southern Oscillation (ENSO) events. The study is useful for early warning and forecasting of negative effects associated with extreme rainfall anomalies across the country, using Climate Hazards Group InfraRed Precipitation with Station (CHIRPS), the National Centers for Environmental Prediction (NCEP) National Center for Atmospheric Research (NCAR) reanalysis sea surface temperature and ERA5 reanalysis datasets, during the period of 1983-2021. Both empirical orthogonal function (EOF), correlation analysis and composite analysis were used to delineate variability, relationship and the related atmospheric circulation between Rwanda seasonal rainfall September to December (SOND) with Indian Ocean Dipole (IOD) and El-Nino Southern Oscillation (ENSO). The results for Empirical Orthogonal Function (EOF) for the reconstructed rainfall data set showed three modes. EOF-1, EOF-2 and EOF-3 with their total variance of 63.6%, 16.5% and 4.8%, Indian ocean dipole (IOD) events resulted to a strong positive correlation of rainfall anomalies and Dipole model index (DMI) (r = 0.42, p value = 0.001, DF = 37) significant at 95% confidence level. The composite analysis for the reanalysis dataset was carried out to show the circulation patterns during four different events correlated with September to December seasonal rainfall in Rwanda using T-test at 95% confidence level. Wind anomaly revealed that there was a convergence of south westerly winds and easterly wind over the study area during positive Indian Ocean Diploe (PIOD) and PIOD with El Nino concurrence event years. The finding of this study will contribute to the enhancement of SOND seasonal rainfall forecasting and the reduction of vulnerability during IOD (ENSO) event years.

Local structural characteristics of Sb_2Te_3 films studied by reverse Monte Carlo modeling

Atomic configuration and connectivity of Sb_2Te_3 thin film are investigated using high-energy X-ray diffraction and reverse Monte Carlo simulation. Atomic model details of Sb_2Te_3 thin film are compared with liquid and amorphous Sb_2Te_3 reported in other article. Simulations show that both Sb–Sb and Te–Te homopolar bonds are present in the models. In phase transition process,atomic configuration of the sample rearranges gradually through the forming of Sb–Te bonds and the breaking of Sb–Sb and Te–Te bonds.

CK2αcauses stemness and chemotherapy resistance in liver cancer through the Hedgehog signaling pathway

Background:Liver cancer is one of the major causes of cancer-related deaths globally.Cancer cell stem-ness and chemotherapy resistance contribute to the high mortality.Although evidence indicates that the alpha subunit of protein kinase 2(CK2α)is involved in several human cancers,its function in liver cancer remains unknown.In the present study,we aimed to elucidate the role of CK2αin liver cancer.Methods:We examined the role of CK2αregulation in stemness and chemotherapy resistance capacity of liver cancer cells.MTT assays,tumor sphere formation assays,RT-PCR,flow cytometry,Western blotting assay,clonogenicity assay,matrigel invasion assay and bioinformatics were conducted in this study.Results:CK2αexpression in the liver cancer tissues was notably upregulated compared with that in the corresponding non-tumorous tissues.The overexpression of CK2αpromoted tumor sphere formation,increased the percentage of CD133(+)and side population cells,caused the resistance of liver cancer cells to 5-FU treatment,increased the expression levels of NANOG,OCT4,SOX2,Gli1 and Ptch1,and enhanced the ability of CD133(+)cell clone formation and invasion.Consistently,the downregulation of CK2αhad the opposite effects.CK2αsilencing inhibited the Hedgehog pathway by reducing the expression of Gli1 and Ptch1.Mechanistically,CK2αregulation on liver cancer cell stemness and chemotherapy resistance was found to be involved in the Hedgehog signaling pathway.Conclusions:Our study may bring some new insights into the occurrence of liver cancer.Furthermore,these findings suggest that targeting CK2αmay be a novel therapeutic strategy for patients with liver cancer.

Comparison and application of different empirical correlations for estimating the hydrate safety margin of oil-based drilling fluids containing ethylene glycol

As the oil and gas industries continue to increase their activity in deep water, gas hydrate hazards will become more serious and challenging, both at present and in the future. Accurate predictions of the hydrate-free zone and the suitable addition of salts and/or alcohols in preparing drilling fluids are particularly important both in preventing hydrate problems and decreasing the cost of drilling operations. In this paper, we compared several empirical correlations commonly used to estimate the hydrate inhibition effect of aqueous organic and electrolyte solutions using experiments with ethylene glycol （EG） as a hydrate inhibitor. The results show that the Najibi et al. correlation （for single and mixed thermodynamic inhibitors） and the Ostergaard et al. empirical correlation （for single thermodynamic inhibitors） are suitable for estimating the hydrate safety margin of oil-based drilling fluids （OBDFs） in the presence of thermodynamic hydrate inhibitors. According to the two correlations, the OBDF, composed of 1.6 L vaporizing oil, 2% emulsifying agent, 1% organobentonite, 0.5% SP-1, 1% LP-1, 10% water and 40% EG, can be safely used at a water depth of up to 1900 m. However, for more accurate predictions for drilling fluids, the effects of the solid phase, especially bentonite, on hydrate inhibition need to be considered and included in the application of these two empirical correlations.

The Development of PCB Enterprise Sewage Monitoring and Management and Controlling Systems

With the development of science and technology, more and more cities are confronted with the water pollution of various degrees. The article is devoted to the introduction of a secondary sewage monitoring and management system which can automatically check the content of different components in the sewage discharged by enterprises and supply data reports with the help of probes, SBCs, PCs, etc. The article includes five parts. The first part introduces the research background, main research work and innovations of this system. The second part introduces the system architecture and system process. The third presents the fundamental working principles of SBCs and the relevant algorithms of PCs. The fourth expounds the problems and deficiencies which may exist in the algorithms. And the last part consists of summary and prospect, providing the possible solution to the deficiencies and looking forward to the future direction of research.

高校有机化学基础课程思政建设探索

有机化学是高校的一门基础课,它不仅为本科生提供核心知识和技能,同时也为其顺利走上科研和就业之路提供坚实的基础。以高校有机化学基础课程为例,探索“立德树人”总目标下“理念引领–铸牢素养–深挖案例–多元评价”的课程思政教育范式。多轮教学实践表明,该范式对提升学生思政素养具有有效性和可行性,并有望成为农林院校基础课程的思政新范式,在其他课程中推广。

Association of DNA methylation/demethylation with the functional outcome of stroke in a hyperinflammatory state

Inflammation is closely related to stroke prognosis, and high inflammation status leads to poor functional outcome in stroke. DNA methylation is involved in the pathogenesis and prognosis of stroke. However, the effect of DNA methylation on stroke at high levels of inflammation is unclear. In this study, we constructed a hyperinflammatory cerebral ischemia mouse model and investigated the effect of hypomethylation and hypermethylation on the functional outcome. We constructed a mouse model of transient middle cerebral artery occlusion and treated the mice with lipopolysaccharide to induce a hyperinflammatory state. To investigate the effect of DNA methylation on stroke, we used small molecule inhibitors to restrain the function of key DNA methylation and demethylation enzymes. 2,3,5-Triphenyltetrazolium chloride staining, neurological function scores, neurobehavioral tests, enzyme-linked immunosorbent assay, quantitative reverse transcription PCR and western blot assay were used to evaluate the effects after stroke in mice. We assessed changes in the global methylation status by measuring DNA 5-mc and DNA 5-hmc levels in peripheral blood after the use of the inhibitor. In the group treated with the DNA methylation inhibitor, brain tissue 2,3,5-triphenyltetrazolium chloride staining showed an increase in infarct volume, which was accompanied by a decrease in neurological scores and worsening of neurobehavioral performance. The levels of inflammatory factors interleukin 6 and interleukin-1 beta in ischemic brain tissue and plasma were elevated, indicating increased inflammation. Related inflammatory pathway exploration showed significant overactivation of nuclear factor kappa B. These results suggested that inhibiting DNA methylation led to poor functional outcome in mice with high inflammation following stroke. Further, the effects were reversed by inhibition of DNA demethylation. Our findings suggest that DNA methylation regulates the inflammatory response in stroke and has an important role in the functional outcome of hyperinflammatory stroke.

孤岛工作面沿空巷道合理支护参数研究

针对围岩松软采空区下孤岛工作面沿空掘巷支护,本文采用FLAC3D数值模拟软件,对不同支护方案下围岩松软采空区孤岛工作面沿空掘巷支护效果进行模拟分析,研究巷道工作面变形演化特征。研究结果显示,单侧工作面采空和两侧都采空的巷道变形量相似,上部7227工作面采空有利于巷道支护,采用联合注浆加固支护方式对松软破碎围岩巷道效果更佳。

Functional dissection of parabrachial substrates in processing nociceptive information

Painful stimuli elicit first-line reflexive defensive reactions and,in many cases,also evoke second-line recuperative behaviors,the latter of which reflects the sensing of tissue damage and the alleviation of suffering.The lateral parabrachial nucleus(lPBN),composed of external-(elPBN),dorsal-(dlPBN),and central/superior-subnuclei(jointly referred to as slPBN),receives sensory inputs from spinal projection neurons and plays important roles in processing affective information from external threats and body integrity disruption.However,the organizational rules of lPBN neurons that provoke diverse behaviors in response to different painful stimuli from cutaneous and deep tissues remain unclear.In this study,we used region-specific neuronal depletion or silencing approaches combined with a battery of behavioral assays to show that slPBN neurons expressing substance P receptor(NK1R)(lPBNNK1R)are crucial for driving pain-associated self-care behaviors evoked by sustained noxious thermal and mechanical stimuli applied to skin or bone/muscle,while elPBN neurons are dispensable for driving such reactions.Notably,lPBNNK1R neurons are specifically required for forming sustained somatic pain-induced negative teaching signals and aversive memory but are not necessary for fear-learning or escape behaviors elicited by external threats.Lastly,both lPBNNK1R and elPBN neurons contribute to chemical irritant-induced nocifensive reactions.Our results reveal the functional organization of parabrachial substrates that drive distinct behavioral outcomes in response to sustained pain versus external danger under physiological conditions.

木质素磺酸钠复合气凝胶滤嘴对卷烟气的净化性能

为探索替代传统醋酸纤维滤嘴的生物质材料和进一步净化卷烟气的有害成分,降低抽烟对人体健康的伤害,文中以木质素磺酸钠、k型卡拉胶为原料,采用溶胶-凝胶法和冷冻干燥法制备出不同配比的复合气凝胶,采用扫描电镜(SEM)、X射线衍射(XRD)、红外光谱(FT-IR)和热重分析(TG)等方法分别对所制备复合气凝胶的表面形貌、官能团结构、热稳定性等进行分析。同时制作醋酸纤维+复合气凝胶滤嘴,通过转盘吸烟机测试其对卷烟气有害气体的净化性能。SEM结果表明,表面形貌显示复合气凝胶具有丰富的微孔孔隙结构和粗糙表面的层状结构;FT-IR和XRD分析表明,卡拉胶的加入并没有改变木质素磺酸钠本身的官能团,卡拉胶与木质素磺酸钠通过物理作用相结合。烟气测试和TG分析结果说明,卷烟气有害成分净化性能随着木质素磺酸钠含量增加而变优,且其热分解温度高于卷烟气进入滤嘴中部时的温度,其在吸烟过程中不会发生热分解,故其为一种理想的卷烟滤嘴潜在材料。

Three novel umami peptides derived from the alcohol extract of the Pacific oyster(Crassostrea gigas):identification,characterizations and interactions with T1R1/T1R3 taste receptors

Oyster(Crassostrea gigas),the main ingredient of oyster sauce,has a strong umami taste.In this study,three potential umami peptides,FLNQDEEAR(FR-9),FNKEE(FE-5),and EEFLK(EK-5),were identified and screened from the alcoholic extracts of the oyster using nano-HPLC-MS/MS analysis,i Umami-Scoring Card Method(i Umami-SCM)database and molecular docking(MD).Sensory evaluation and electronic tongue analysis were further used to confirm their tastes.The threshold of the three peptides ranged from 0.38 to 0.55 mg/m L.MD with umami receptors T1R1/T1R3 indicated that the electrostatic interaction and hydrogen bond interaction were the main forces involved.Besides,the Phe592 and Gln853 of T1R3 were the primary docking site for MD and played an important role in umami intensity.Peptides with two Glu residues at the terminus had stronger umami,especially at the C-terminus.These results contribute to the understanding of umami peptides in oysters and the interaction mechanism between umami peptides and umami receptors.

变废为宝:以有机玻璃废弃物为原料制备高黏合强度的水基黏合剂——大学化学综合实验设计

本文介绍了以有机玻璃废弃物为原料制备高黏合强度的水基黏合剂的实验方法、黏合剂组成分析及黏合性能研究等内容。本实验可以锻炼学生的合成技能,拓宽学生的化学视野,培养学生的创新思想。同时,教师还可以针对本实验涉及的能源和环境问题对学生进行思政教育,激发学生努力学习,用专业知识为国效力的决心和使命感。