原子层制造的研究现状与科学挑战

原子层制造是指加工精度达到原子层量级的可控制造技术,包括原子层去除、添加、迁移等。针对信息、能源、航空航天等领域核心零部件超高性能构建的发展需求,通过原子层可控去除制造全频段原子级精度无损表面,并结合原子层增材制造原子级新结构,有望实现特殊功能的有效创成,保证超高性能的安全可靠。另外,后摩尔时代先进芯片的制造工艺将迈入亚纳米物理极限,原子层制造需求贯穿芯片制造工艺的全流程。本文阐述了原子层制造技术的发展需求与研究进展,围绕原子层抛光、原子层沉积/刻蚀、原子层损伤控制、原子层工艺与装备等领域,梳理了原子层制造的发展方向及研究目标,凝练了原子层制造领域未来的关键科学问题及面临的挑战,探讨了前沿研究方向和发展战略。

Characteristics of laser-induced breakdown spectroscopy of liquid slag

Rapid online analysis of liquid slag is essential for optimizing the quality and energy efficiency of steel production. To investigate the key factors that affect the online measurement of refined slag using laser-induced breakdown spectroscopy(LIBS), this study examined the effects of slag composition and temperature on the intensity and stability of the LIBS spectra. The experimental temperature was controlled at three levels: 1350℃, 1400℃, and 1450℃. The results showed that slag composition and temperature significantly affected the intensity and stability of the LIBS spectra. Increasing the Fe content and temperature in the slag reduces its viscosity, resulting in an enhanced intensity and stability of the LIBS spectra. Additionally, 42 refined slag samples were quantitatively analyzed for Fe, Si, Ca, Mg, Al, and Mn at 1350℃, 1400℃, and 1450℃.The normalized full spectrum combined with partial least squares(PLS) quantification modeling was used, using the Ca Ⅱ 317.91 nm spectral line as an internal standard. The results show that using the internal standard normalization method can significantly reduce the influence of spectral fluctuations. Meanwhile, a temperature of 1450℃ has been found to yield superior results compared to both 1350℃ and 1400℃, and it is advantageous to conduct a quantitative analysis of the slag when it is in a “water-like” state with low viscosity.

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.

Time-resolved ultra-small-angle X-ray scattering beamline(BL10U1)at SSRF

The construction of a new beamline,BL10U1,was completed at the Shanghai synchrotron radiation facility in 2020.This multipurpose beamline was designed to provide X-ray scattering techniques such as ultra-small-angle X-ray scattering(USAXS),small-angle X-ray scattering(SAXS),wide-angle X-ray scattering,and microfocus SAXS(μSAXS)for a broad user community.To realize fast time-resolved USAXS experiments,the beamline adopted an in-vacuum undulator with a total length of 1.6 m as the photon source.An in-house cryogenic-cooled double multilayer monochromator was installed to deliver a photon flux of approximately 10^(13) photons/s at a photon energy of 10 keV.The three-year successful operation of this beamline demonstrated that the monochromator operated smoothly,as expected.BL10U1 has three end stations in succession:USAXS end station,μSAXS end station,and end station for industrial applications.The minimum scattering vector q~0.0042 nm^(-1) at 10 keV can be achieved at the USAXS end station equipped with a 28 m-long and 1.8 m-diameter vacuum flight tube.At theμSAXS end station,a beam spot of less than 10×8μm was achieved for micro-SAXS experiments.In contrast,in situ experimental instruments up to 5 m high and 8 m wide can be mounted at the industrial application end station,which offers industrial scientists the opportunity to use their large industrial equipment.BL10U1 opens up a new capability to investigate phenomena such as non-equilibrium and dynamic processes of materials with a wide length scale from angstroms to micrometers with millisecond time resolution.In this paper,we also report beamline design considerations and commissioning results.

Study of the reaction mechanism for preparing powdered activated coke with SO_(2)adsorption capability via one-step rapid activation method under flue gas atmosphere

In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction mechanism is summarized.Results indicate that the reaction process of this method can be divided into three stages:stage I is the rapid release of volatiles and the rapid consumption of O_(2),primarily occurring within a reaction time range of 0-0.5 s;stage II is mainly the continuous release and diffusion of volatiles,which is the carbonization and activation coupling reaction stage,and the carbonization process is the main in this stage.This stage mainly occurs at the reaction time range of 0.5 -2.0 s when SL-coal is used as material,and that is 0.5-3.0 s when JJ-coal is used as material;stage III is mainly the activation stage,during which activated components diffuse to both the surface and interior of particles.This stage mainly involves the reaction stage of CO_(2)and H2O(g)activation,and it mainly occurs at the reaction time range of 2.0-4.0 s when SL-coal is used as material,and that is 3.0-4.0 s when JJ-coal is used as material.Besides,the main function of the first two stages is to provide more diffusion channels and contact surfaces/activation sites for the diffusion and activation of the activated components in the third stage.Mastering the reaction mechanism would serve as a crucial reference and foundation for designing the structure,size of the reactor,and optimal positioning of the activator nozzle in PAC preparation.

Omental fibroma combined with right indirect inguinal hernia masquerades as a scrotal tumor: A case report

BACKGROUND The most common causes of scrotal enlargement in patients include primary tumor of the scrotum,inflammation,hydrocele of the tunica vaginalis,and indirect inguinal hernia;scrotal enlargement caused by external tumors of the scrotum is rare.The patient had both a greater omentum tumor and an inguinal hernia,and the tumor protruded into the scrotum through the hernia sac,which is even rarer.Moreover,omental tumors are mostly metastatic,and primary omental fibroma is rare.CASE SUMMARY Here,we report a rare case of a 25-year-old young man with scrotal enlargement and pain for 3 months.Preoperative examination and multidisciplinary discu-ssions considered intra-abdominal tumor displacement and inguinal hernia,and intraoperative exploration confirmed that the greater omentum tumor protruded into the scrotum.Therefore,tumor resection and tension-free inguinal hernia repair were performed.The final diagnosis was benign fibroma of the greater omentum accompanied by an indirect inguinal hernia.CONCLUSION This unusual presentation of a common inguinal hernia disease illustrates the necessity of performing detailed history taking,physical examination,and imaging before surgery.

Protective Effect of Naringenin on Acute Myocardial Ischemia-reperfusion Injury in Rats

[Objectives]To investigate the protective mechanism of naringenin on acute myocardial ischemia-reperfusion injury(AMI-RI)in Sprague-Dawley(SD)rats.[Methods]A total of 32 SD rats with AMI-RI model construction were randomly divided into AMI-RI model control group and citrus pigment A/B/C groups(n=8).The naringenin A,B,and C groups were administrated 20,40 and 80 mg/(kg•d)for 10 d.The AMI group served as the negative control and was not treated.At the conclusion of the treatment regimen,a sample of intraventricular blood was collected for the purpose of measuring lactate dehydrogenase(LDH),glutathione peroxidase(GLH-PX),nitric oxide(NO),and superoxide dismutase(SOD)levels.Additionally,myocardial tissue was identified within the ischemic region.The content of malondialdehyde(MDA)was determined by inducing nitric oxide synthase(iNOS)and endodermal nitric oxide synthase(eNOS)positive cells in the left anterior descending coronary artery.[Results]Following citrus treatment,the contents of GLH-PX and SOD in ventricular blood of the citrus B group were found to be significantly elevated,while the contents of NO and LDH in myocardial MDA and ventricle were observed to be significantly reduced.The number of eNOS-positive cells was significantly increased,while the number of iNOS-positive cells was significantly decreased.The difference was statistically significant when compared with the AMI-RI group(P<0.05).The changes observed in the above indicators in the citrus C group were more pronounced than those observed in the citrus B group.The difference between the citrus C and the B group was statistically significant(P<0.05),indicating that this effect is concentration dependent.[Conclusions]In addition to its ability to inhibit myocardial lipid peroxidation during AMI-RI by increasing SOD activity,naringenin may also affect the synthesis and release of NO by regulating eNOS and iNOS,thereby achieving protection against AMI-RI.One effect is enhanced as the dose of the drug increases.

Analysis of risk factors for postoperative anxiety and depression in endometriosis patients with reproductive intention

BACKGROUND The occurrence of postoperative depression and anxiety in patients with endomet-riosis(EMS)not only causes psychological distress,but may also harm their physical health.AIM To explore the postoperative depression status,and its influencing factors,of EMS patients with reproductive intention.METHODS A total of 321 EMS patients with reproductive intent were included.Using the self-rating anxiety scale and self-rating depression scale,EMS patients with anxiety or depression were distinguished.A clinical model for predicting anxiety or depression in EMS patients was constructed and evaluated using a nomogram,receiver operating characteristic curve,and calibration curve.RESULTS The results of the single factor analysis showed that smoking,coffee,EMS stage,chronic pelvic pain,and sexual discomfort may be related to anxiety.Further,smoking,drinking,spouse,annual household income and EMS stage may be related to depression in EMS patients.Multivariate logistic regression illustrated that smoking,coffee,chronic pelvic pain and sexual discomfort may be inde-pendent risk factors for anxiety in EMS patients,while smoking,EMS stage(Phase III and Phase IV),spouse and high annual household income may be independent risk factors for depression in EMS patients.Additionally,the models used to predict the risk of anxiety or depression in EMS patients have good predictive value.CONCLUSION The anxiety and depression of EMS patients may be related to many factors.In clinical treatment,additional attention should be paid to the psychological status of EMS patients.

Effect of Salvia Miltiorrhiza Injection on Blood Pressure and Cardiac Function in Rats with Gestational Hypertension and Preeclampsia

Objective: This study is to observe the effects of Salvia miltiorrhiza injection on blood pressure and cardiac function in rats with pregnancy-induced hypertension and preeclampsia. Methodology: Syncytiotrophoblast microvilli (stbm) and l-arginine nitrosyl methyl ester were screened out via caudal vein injection. Twenty gestational hypertension-preeclampsia model SD (Sprague Dawley) rats successfully induced by L-NAME (L-arginine Nitrosyl methyl ester) were randomly divided into 2 groups (model group and Danshen injection group, n = 10). Then another 10 normal pregnant SD rats without model were selected as blank control group. The Salvia miltiorrhiza injection group was given Salvia miltiorrhiza injection (0.5 g?kg?1?d?1) through tail vein, and the control group and model group were given equal volume of normal saline through tail vein injection. All three groups were treated by tail vein injection once a day (d) for 7 days. After treatment, heart rate (HR), Systolic pressure (SP), diastolic pressure (DP) and mean arterial pressure (MAP) were measured by tail artery. Left ventricular end-diastolic diameter (LVDd) and Left ventricular end systolic diameter (LVDs) were recorded by echocardiography. Left ventricular end diastolic pressure (LVEDP), left ventricular systolic pressure (LVSP), left ventricular ejection fraction (left ventricular ejection) fraction, LVEF) and the maximum rate of increase/decrease of left ventricular pressure during isovolemic systole (+dp/dtmax/?dp/dtmax);Endothelin-1 (ET-1) levels in rat tail vein blood were detected by ELISA. Results: SP, DP, MP, HR, LVSP, LVDs and ?dp/dtmaxx were all decreased, plasma ET-1 expression was low, and LVDd, LVEDP, LVEF, and +dp/dtmax were all increased in the Salvia miltiorroot injection group, with statistical significance compared to the model group (p Conclusion: Salvia miltiorrhiza injection can improve the cardiac function and reduce blood pressure in rats with pregnancy-induced hypertension and preeclampsia, and the mechanism may be related to alleviating systemic arteriolar spasm by regulating ET-1 level.

Brief introduction to the historical development and therapeutic effects of cupping therapy in traditional Chinese medicine

Cupping therapy (CT) is an ancient traditional and complementary medicine practice. Recently, there has been a growing evidence of its potential benefits in the treatment of various diseases. The CT has been constantly developing with the emergence of various modern and improved cupping devices. It is now evident that cupping could adjust the Qi, blood, Yin and Yang, dredge the meridian, as well as relieve the effect of illness, achieve fitness and relative equilibrium of Yin-Yang. It exerts its effects through the negative pressure suction via the mechanical and thermal stimulations, and the negative pressure effects induced by cupping. This article gives an overview of CT practice, its historical development, as well as its therapeutic effects and mechanism. Furthermore, a new and updated classification of CT was briefly introduced.

闪速吹炼炉内颗粒在不同操作参数下的分布与演化规律

通过开展工业试验揭示闪速吹炼炉内颗粒质量和粒径的分布与演化规律,同时研究不同配风参数对颗粒分布的影响。结果表明,颗粒在反应塔内的下落过程中,其平均粒径增长通常为2~3倍,且聚并后的大颗粒主要分布在料锥中部和外部;而导致该现象出现的原因是较高的湍流强度和颗粒分布密度、以及天然气燃烧的位置使该位置处颗粒升温熔融、并发生碰撞和聚并。另外,提高分散风与工艺风动量比能使物料颗粒在反应塔内的分布更加均匀,更有利于冰铜的氧化反应。相较于调整工艺风参数,改变分散风能更有效地提高颗粒的空间分布范围。

Mitochondrial carnitine palmitoyltransferase-Ⅱ dysfunction: A possible novel mechanism for nonalcoholic fatty liver disease in hepatocarcinogenesis

Nonalcoholic fatty liver disease(NAFLD)or metabolic-associated fatty liver disease has been characterized by the lipid accumulation with injury of hepatocytes and has become one of the most common chronic liver diseases in the world.The complex mechanisms of NAFLD formation are still under identification.Carnitine palmitoyltransferase-Ⅱ(CPT-Ⅱ)on inner mitochondrial membrane(IMM)regulates long chain fatty acidβ-oxidation,and its abnormality has had more and more attention paid to it by basic and clinical research in NAFLD.The sequences of its peptide chain and DNA nucleotides have been identified,and the catalytic activity of CPT-Ⅱ is affected on its gene mutations,deficiency,enzymatic thermal instability,circulating carnitine level and so on.Recently,the CPT-Ⅱ dysfunction has been discovered in models of liver lipid accumulation.Meanwhile,the malignant transformation of hepatocyte-related CD44^(+) stem T cell activation,high levels of tumor-related biomarkers(AFP,GPC3)and abnormal activation of Wnt3a expression as a key signal molecule of the Wnt/β-catenin pathway run parallel to the alterations of hepatocyte pathology.This review focuses on some of the progress of CPT-Ⅱ inactivity on IMM with liver fatty accumulation as a possible novel pathogenesis for NAFLD in hepatocarcinogenesis.

Genome sequencing revealed the red-flower trait candidate gene of a peach landrace

Peach(Prunus persica)is an economically important fruit crop globally and an excellent material for genomic studies.While considerable progress has been made in unveiling trait-associated genes within cultivars and wild relatives,certain novel genes controlling valuable traits in peach landraces,such as the red-flowering gene,remained unclear.In this study,we sequenced and assembled the diploid genome of the red-flower landrace‘Yingzui’(abbreviated as‘RedY’).Multi-omics profiling of red petals of‘RedY’revealed the intensified red coloration associated with anthocyanins accumulation and concurrent decline in f lavonols.This phenomenon is likely attributed to a natural variant of Flavonol Synthase(FLS)harboring a 9-bp exonic insertion.Intriguingly,the homozygous allelic configurations of this FLS variant were only observed in red-flowered peaches.Furthermore,the 9-bp sequence variation tightly associated with pink/red petal color in genome-wide association studies(GWAS)of collected peach germplasm resources.Functional analyses of the FLS variant,purified from procaryotic expression system,demonstrated its diminished enzymatic activity in f lavonols biosynthesis,impeccably aligning with the cardinal trait of red flowers.Therefore,the natural FLS variant was proposed as the best candidate gene for red-f lowering trait in peach.The pioneering unveiling of the red-flowered peach genome,coupled with the identification of the candidate gene,expanded the knowledge boundaries of the genetic basis of peach traits and provided valuable insights for future peach breeding efforts.

Research progress on the role of cold-sensitive channel TRPM8 in controlling low temperature-induced bone metabolic imbalance

With increasing aging population,osteoporosis has emerged as a public health problem worldwide.Epidemiological data reveal that the prevalence of osteoporosis in cold regions is high,and low temperatures may crucially affect bone mass.Recent studies have found that the transient receptor potential melastatin-8(TRPM8)channel,a cold-sensitive ion channel,can sense cold environment,and can be activated in cold environment.It may play an antagonistic role in low temperature-induced bone mass reduction.Mechanistically,this function may be ascribed to the activation of TRPM8 channel proteins in human bone marrow mesenchymal stem cells(hBM-MSCs),which causes osteoblast differentiation and mineralization in the bone.TRPM8 channel on the surface of brown adipocytes participates in the thermogenesis in brown adipose tissue(BAT)and the regulation of whole-body energy balance to maintain bone homeostasis.TRPM8 may be involved in bone remodeling throughout life.This paper reviews recent research on the possible antagonistic mechanism of TRPM8 in signaling pathways related to low temperature-induced bone mass loss and assesses the possibility of TRPM8 as a molecular target for the prevention and treatment of low temperature-induced osteoporosis in cold regions.

基于血栓弹力图抗栓治疗动脉粥样硬化性脑梗死的疗效分析

目的探讨基于血栓弹力图(TEG)抗栓治疗急性动脉粥样硬化性脑梗死的疗效。方法选取连云港市第二人民医院收治的184例急性动脉粥样硬化性脑梗死(ACI)患者。随机分为:A组,阿司匹林抗栓治疗;B组,氯吡格雷抗栓治疗;C组,氯吡格雷联合阿司匹林抗栓治疗;D组,用血栓弹力图仪检测血小板抑制率,选择血小板抑制率高的抗栓药物治疗,每组46例。比较患者治疗前后神经功能缺损评分(NIHSS)、日常生活能力评分(ADL)、微栓子(MES)阳性率改善情况,统计卒中复发率及出血性事件的发生率。结果治疗后4组患者的NIHSS评分下降,而ADL评分提高(P<0.05),且治疗后C、D组NIHSS评分低于A、B组,ADL评分高于A、B组(P <0.05)。治疗后,C、D两组临床治疗有效率高于A组(P<0.0167)。治疗后,4组患者的MES阳性率均降低(P<0.05),且C组MES阳性率均低于A、B组(P<0.0167)。4组胃肠道不适、病死率比较,差异无统计学意义(P>0.05);治疗后C、D两组复发率低于A组(P <0.0167),但C、D两组间比较,差异无统计学意义(P>0.05)。出血事件B、D两组低于C组(P <0.0167)。结论采用基于血栓弹力图个体化治疗ACI的抗栓效果优于阿司匹林和氯吡格雷单用,同时能够有效降低双抗药物联合治疗带来的出血性事件风险。

Platelet count combined with right liver volume and spleen volume measured by magnetic resonance imaging for identifying cirrhosis and esophageal varices

AIM: To determine whether the combination of platelet count(PLT) with spleen volume parameters and right liver volume(RV) measured by magnetic resonance imaging(MRI) could predict the Child-Pugh class of liver cirrhosis and esophageal varices(EV).METHODS: Two hundred and five cirrhotic patients with hepatitis B and 40 healthy volunteers underwent abdominal triphasic-enhancement MRI and laboratory examination of PLT in 109/L. Cirrhotic patients underwent endoscopy for detecting EV. Spleen maximal width(W), thickness(T) and length(L) in mm together with spleen volume(SV) and RV in mm3 were measured by MRI, and spleen volume index(SI) in mm3 was obtained by W × T × L. SV/PLT, SI/PLT and RV × PLT/SV(RVPS) were calculated and statistically analyzed to assess cirrhosis and EV.RESULTS: SV/PLT(r = 0.676) and SI/PLT(r = 0.707) increased, and PLT(r =-0.626) and RVPS(r =-0.802) decreased with the progress of Child-Pugh class(P < 0.001 for all). All parameters could determine the presence of cirrhosis, distinguish between each class of Child-Pugh class, and identify the presence of EV [the areas under the curve(AUCs) = 0.661-0.973]. A m o n g p a ra m e t e r s, R V P S c o u l d b e s t d e t e r m i n e presence and each class of cirrhosis with AUCs of 0.973 and 0.740-0.853, respectively; and SV/PLT could best identify EV with an AUC of 0.782.CONCLUSION: The combination of PLT with SV and RV could predict Child-Pugh class of liver cirrhosis and identify the presence of esophageal varices.

Blood perfusion of the contralateral testis evaluated with contrast-enhanced ultrasound in rabbits with unilateral testicular torsion

The changes of blood perfusion of contralateral testis after unilateral testicular torsion remain controversial.In this study,28 New Zealand white male rabbits were randomly divided into five groups.Group A(n=8),the control group,underwent a sham operation on the unilateral testis without inducing testicular torsion.In groups B,C,and D(n=5 each),unilateral testicular torsion was induced,and,after 3,6 or 24 h,respectively,detorsion was performed.In group E(n=5),permanent unilateral testicular torsion was applied.Contrast-enhanced ultrasound was used to observe the blood perfusion of the contralateral testis at the following stages:pre-torsion(preopration),immediately post-torsion(postopration),pre-detorsion,immediately post-detorsion,and late-stage post-detorsion(6-12 h post-detorsion in groups B-D)or at a similar time point(15-21 h post-torsion in group E).Time-intensity curves were generated,and the following parameters were derived and analyzed:arrival time,time to peak intensity,peak intensity,and half-time of the descending peak intensity.The analysis revealed that blood perfusion of the contralateral testis increased immediately after testicular torsion on the opposite side(P<0.05),which increased with prolonged testicular torsion of the other testis.This research demonstrated that contrast-enhanced ultrasound was valuable in evaluating blood perfusion of the contralateral testis after unilateral testicular torsion.

Reversible immortalization of human hepatocytes mediated by retroviral transfer and site-specific recombination

AIM: To establish a method for the reversible immortalization of human hepatocytes, which may offer a good and safe source of hepatocytes for practical applications.

Application of acoustic radiation force impulse imaging for the evaluation of focal liver lesion elasticity

BACKGROUND: Acoustic radiation force impulse (ARFI) imaging is a new elastography method for the evaluation of tissue stiffness. This study aims to evaluate the performance of ARFI in noninvasive assessment of the tissue stiffness of focal liver lesion (FLL) and to explore its potential value in the differential diagnosis of FLL. METHODS: ARFI was performed in 140 patients with 154 FLLs, which included 28 hemangiomas (ANGIs), 14 focal nodular hyperplasias (FNHs), 61 hepatocellular carcinomas (HCCs), 39 metastases and 12 cholangiocellular carcinomas (CCCs). Virtual touch tissue quantification (VTTQ) values were obtained, analyzed and compared. The area under the receiver operating characteristic curve (AUROC) and optimal cut-off values were obtained using a receiver operating characteristic (ROC) curve analysis to assess diagnostic performance. All cases were definitively diagnosed using histopathology, CT, MRI or contrast-enhanced ultrasound. RESULTS: The VTTQ median values of ANGI, FNH, HCC metastasis and CCC were 1.30, 1.80, 2.52, 3.08 and 3.89 m/s respectively. A significant increase in the VTTQ values of different lesions was observed: ANGI【FNH【HCC【metastasis 【CCC (P【0.001). The AUROC (95% CI) of VTTQ values was 0.94 (0.90-0.98) for ANGI, 0.91 (0.87-0.96) for malignant lesions and 0.87 (0.79-0.94) for CCC. The sensitivity and specificity for ANGI (86.5%, 89.3%, respectively), malignancy (81.3% 92.9%, respectively), and CCC (91.7%, 72.5%, respectively) were associated with VTTQ cut-off values of 1.76, 2.22 and 3.00 m/s respectively.CONCLUSIONS: ARFI can accurately and objectively assess the elasticity of lesions by obtaining the shear wave elastic value of FLL with VTTQ. Therefore, ARFI is a novel, simple, noninvasive and useful diagnostic method for the characterization of FLL.

Parametric study of gas−liquid two-phase flow field in horizontal stirred tank

Based on Fluent software,the gas−liquid two-phase flow in the horizontal stirred tank was simulated with SST k−ωturbulence model,Eulerian−Eulerian two-fluid model,and multi-reference flame method.The mixing process in the tank was calculated by tracer method.The results show that increasing the rotating speed or gas flow is conducive to a more uniform distribution of the gas phase and accelerates the mixing of the liquid phase.When the rotating speed exceeds 93 r/min,the relative power demand remains basically constant.The change in the inclination angle of the upper impeller has minimal effect on the gas phase distribution.When the inclination angle is 50°,the relative power demand reaches the maximum.An appropriate increase in the impeller distance from the bottom improves the gas holdup and gas phase distribution but increases the liquid phase mixing time.