Pericytes protect rats and mice from sepsis-induced injuries by maintaining vascular reactivity and barrier function:implication of miRNAs and microvesicles

Background Vascular hyporeactivity and leakage are key pathophysiologic features that produce multi-organ damage upon sepsis.We hypothesized that pericytes,a group of pluripotent cells that maintain vascular integrity and tension,are protective against sepsis via regulating vascular reactivity and permeability.Methods We conducted a series of in vivo experiments using wild-type(WT),platelet-derived growth factor receptor-β(PDGFR-β)-Cre+mT/mG transgenic mice and Tie2-Cre+Cx43^(flox/flox)mice to examine the relative contribution of pericytes in sepsis,either induced by cecal ligation and puncture(CLP)or lipopolysaccharide(LPS)challenge.In a separate set of experiments with Sprague-Dawley(SD)rats,pericytes were depleted using CP-673451,a selective PDGFR-βinhibitor,at a dosage of 40 mg/(kg·d)for 7 consecutive days.Cultured pericytes,vascular endothelial cells(VECs)and vascular smooth muscle cells(VSMCs)were used for mechanistic investigations.The effects of pericytes and pericyte-derived microvesicles(PCMVs)and candidate miRNAs on vascular reactivity and barrier function were also examined.Results CLP and LPS induced severe injury/loss of pericytes,vascular hyporeactivity and leakage(P<0.05).Transplantation with exogenous pericytes protected vascular reactivity and barrier function via microvessel colonization(P<0.05).Cx43 knockout in either pericytes or VECs reduced pericyte colonization in microvessels(P<0.05).Additionally,PCMVs transferred miR-145 and miR-132 to VSMCs and VECs,respectively,exerting a protective effect on vascular reactivity and barrier function after sepsis(P<0.05).miR-145 primarily improved the contractile response of VSMCs by activating the sphingosine kinase 2(Sphk2)/sphingosine-1-phosphate receptor(S1PR)1/phosphorylation of myosin light chain 20 pathway,whereas miR-132 effectively improved the barrier function of VECs by activating the Sphk2/S1PR2/zonula occludens-1 and vascular endothelial-cadherin pathways.Conclusions Pericytes are protective against sepsis through regulating vascular reactivity and barrier function.Possible mechanisms include both direct colonization of microvasculature and secretion of PCMVs.

Tuning the reactivity of TiO_(2)layer with uniform distribution of Sub-5 nm Fe_(2)O_(3)particles via in situ voltage-assisted oxidation for robust catalytic reduction

The trade-off between efficiency and stability has limited the application of TiO_(2)as a catalyst due to its poor surface reactivity.Here,we present a modification of a TiO_(2)layer with highly stable Sub-5 nm Fe_(2)O_(3)nanoparticles(NP)by modulating its structure-surface reactivity relationship to attain efficiency-stability balance via a voltage-assisted oxidation approach.In situ simultaneous oxidation of the Ti substrate and Fe precursor using high-energy plasma driven by high voltage resulted in uniform distribution of Fe_(2)O_(3)NP embedded within porous TiO_(2)layer.Comprehensive surface characterizations with density functional theory demonstrated an improved electronic transition in TiO_(2)due to the presence of surface defects from reactive oxygen species and possible charge transfer from Ti to Fe;it also unexpectedly increased the active site in the TiO_(2)layer due to uncoordinated electrons in Sub-5 nm Fe_(2)O_(3)NP/TiO_(2)catalyst,thereby enhancing the adsorption of chemical functional groups on the catalyst.This unique embedded structure exhibited remarkable improvement in reducing 4-nitrophenol to 4-aminophenol,achieving approximately 99%efficiency in 20 min without stability decay after 20 consecutive cycles,outperforming previously reported TiO_(2)-based catalysts.This finding proposes a modified-electrochemical strategy enabling facile construction of TiO_(2)with nanoscale oxides extandable to other metal oxide systems.

Wettability,reactivity,and interface structure in Mg/Ni system

The sessile drop method was applied to the experimental investigation of the wetting and spreading behaviors of liquid Mg drops on pure Ni substrates.For comparison,the experiments were performed in two variants:(1)using the Capillary Purification(CP)procedure,which allows the non-contact heating and squeezing of a pure oxide-free Mg drop;(2)by classical Contact Heating(CH)procedure.The high-temperature tests were performed under isothermal conditions(CP:760℃for 30 s;CH:715℃for 300 s)using Ar+5 wt%H_(2) atmosphere.During the sessile drop tests,images of the Mg/Ni couples were recorded by CCD cameras(57 fps),which were then applied to calculate the contact angles of metal/substrate couples.Scanning and transmission electron microscopy analyses,both coupled with energy-dispersive X-ray spectroscopy,were used for detailed structural characterization of the solidified couples.It was found that an oxide-free Mg drop obtained by the CP procedure showed a wetting phenomenon on the Ni substrate(an average contact angleθ<90°in<1 s),followed by fast spreading and good wetting over the Ni substrate(θ_((CP))~20°in 5 s)to form a final contact angle ofθ_(f(CP))~18°.In contrast,a different wetting behavior was observed for the CH procedure,where the unavoidable primary oxide film on the Mg surface blocked the spreading of liquid Mg showing apparently non-wetting behavior after 300 s contact at the test temperature.However,in both cases,the deep craters formed in the Ni substrates under the Mg drops and significant change in the structure of initially pure Mg drops to Mg-Ni alloys suggest a strong dissolution of Ni in liquid Mg and apparent values of the final contact angles measured for the Mg/Ni system.

Correction to:Assembly-level analysis on temperature coefficient of reactivity in a graphite-moderated fuel salt reactor fueled with low-enriched uranium

Following publication of the original article,the authors observed that both Fig.5 and Fig.4 depict the same image.Figure 5 was inaccurately referenced and displayed.The correct Fig.5 is copied below:The original article has been updated.

Evaluation of the Oxidation Reactivity and Behavior of Exhaust Soot Particles from Diesel Engines with Different Emission Levels

The aim of this study was to investigate the oxidation reactivity and behavior of exhaust particulate matter(PM)from diesel engines.PM samples from two diesel engines(1K,CY4102)with different emission levels were collected by a thermophoretic system and a quartz filter.The oxidation reactivity,oxidation behaviors,and physicochemical properties of the PM samples were analyzed using thermogravimetric analysis(TGA),high-resolution transmission electron microscopy(HRTEM),Fourier-transform infrared spectrometry(FTIR),and Raman spectroscopy.The results showed that there was a great difference in the oxidation reactivity of soot particles emitted by the two different diesel engines.A qualitative analysis of the factors influencing oxidation reactivity showed that the nanostructure,degree of graphitization,and relative concentration of aliphatic C—H functional groups were the most important factors,whereas no significant correlation was found between the primary particle size and activation energy of the diesel soot.Based on the oxidation behavior analysis,the diesel soot particles exhibited both internal and surface oxidation modes during the oxidation process.Surface oxidation was dominant during the initial stage,and as oxidation progressed,the mode gradually changed to internal oxidation.Internal oxidation mode of soot particles from the 1K engine was significantly higher than that of CY4102.

Experimental Study of the Influence of Intrinsic Parameters on the Thermal Reactivity of Sawdust, Polyethylene Terephthalate and Composite

Several works have been based on the study of thermal variations in biomass to derive more valuable products such as fuels capable of replacing oil in the event of a crisis or activated carbon used as an adsorbent material, widely used in industry for the elimination of unwanted materials, both in liquid and gaseous environments. A study of thermal parameters such as: heating speed, retention time, drying temperature, carbonization temperature, particle size, was carried out with the aim of determining the characteristic factors of the carbonization of Polyethylene terephthalate (PET), sawdust (SC) and sawdust/polyethylene terephthalate (CPS) mixture. The results of the immediate analysis revealed a very low level of ash in PET (0.013%) compared to the level of ash in sawdust (2.9%), as well as a high level of fixed carbon (82.960%), which suggests the presence of mineral oxides and a significant carbon matrix unlike PET, which indicates a very significant organic matrix (essentially made up of organic matter) with the absence of mineral oxides. The study of thermal parameters showed the water loss from Sawdust (SC) and the Sawdust/Polyethylene terephthalate (CPS) mixture, an increase with temperature, unlike that of PET whose variation is essentially zero. Without heat treatment, sawdust alone contains approximately 7% water. The optimal drying temperature for this study is 110˚C for a stay of 24 hours. It appears that the largest mass losses for the PET samples are between 87.19% and 96.05%, followed by that of the mixture, between 47.33% and 64.37%. And the lowest are observed, those of sawdust (from 24.02% to 62.6%). However, here we can say that the influence of the mass is not great, given the slight difference between the losses by temperature. The results of the study of the influence of grain size showed that the differences are insignificant, even if we vary the diameter of the grains from simple to triple. To better minimize physical constraints such as the intragranular diffusibility of the volatile matter and the homogeneity of the temperature in the grains, 75 μm particles are found to be optimal for our study. It can be noted when studying the heating rate that the mass loss at the end of the reaction is approximately the same depending on each precursor material. However, it has been demonstrated that the heating rate strongly influences the nature of the reaction products both for volatile materials and for the solid residue as well as on the kinetic parameters of the chemical reaction. Furthermore, the variation in apparent density shows a decrease as a function of the increase in the residence time of the materials in the reactor. As the carbonization time increases, the apparent density decreases. We note, for the lignocellulosic material, that the apparent density stabilizes after 60 minutes.

Synergistic activation of smithsonite with copper-ammonium species for enhancing surface reactivity and xanthate adsorption

Copper ions(Cu^(2+))are usually added to activate the sulfidized surface of zinc oxide minerals to enhance xanthate attachment using sulfidization xanthate flotation technology.The adsorption of Cu^(2+)and xanthate on the sulfidized surface was investigated in various systems,and its effect on the surface hydrophobicity and flotation performance was revealed by multiple analytical methods and experiments.X-ray photoelectron spectroscopy(XPS)and time-of-flight secondary ion mass spectrometry(To F-SIMS)characterization demonstrated that the adsorption of Cu^(2+)on sulfidized smithsonite surfaces increased the active Cu—S content,regardless of treatment in any activation system.The sulfidized surface pretreated with NH_(4)^(+)-Cu^(2+)created favorable conditions for the adsorption of more Cu^(2+),significantly enhancing the smithsonite reactivity.Zeta potential determination,ultraviolet(UV)-visible spectroscopy,Fourier transform-infrared(FT-IR)measurements,and contact angle detection showed that xanthate was chemically adsorbed on the sulfidized surface,and its adsorption capacity in various systems was illustrated from qualitative and quantitative aspects.In comparison to the Na2S–Cu^(2+)and Cu^(2+)–Na2S–Cu^(2+)systems,xanthate exhibited a higher adsorption capacity on sulfidized smithsonite surfaces in NH_(4)^(+)-Cu^(2+)–Na2S–Cu^(2+)system.Hence,activation with Cu^(2+)–NH4+synergistic species prior to sulfidization significantly enhanced the mineral surface hydrophobicity,thereby increasing its flotation recovery.

Morphology,Nanostructure,and Oxidation Reactivity of Particulate Matter Emitted by Diesel Blending with Various Aromatics

This study aims to analyze the influence of the polycyclic aromatic hydrocarbon(PAH)content in diesel on the physical and chemical properties of diesel soot particles.Four diesel fuels with different PAH content were tested on a 11.6 L direct-injection diesel engine.The raw particulate matter(PM)before the after-treatment devices was collected using the thermophoresis sampling system and the filter sampling system.A transmission electron microscope and Raman spectrometer are used to analyze the physical properties of the soot particles,including morphology,primary particle size distribution,and graphitization degree.A Fourier transform infrared spectrometer and thermogravimetric analyzer are used to characterize the surface chemical composition and oxidation reactivity of soot particles,respectively.The results show that as the PAH content in the fuel decreases,the size of the primary soot particles decreases from 29.58 to 26.70 nm.The graphitization degree of soot particles first increases and then decreases,and the relative content of the aliphatic hydrocarbon functional groups of soot particles first decreases and then increases.The T_(10),T_(50),and T_(90) of soot from high-PAH fuel are 505.3,589.3,and 623.5℃,while those from low-PAH fuel are 480.1,557.5,and 599.2℃,respectively.This indicates that exhaust PM generated by the low-PAH fuel has poor oxidation reactivity.However,as the PAH content in fuel is further decreased,the excessively high cetane number may cause uneven mixing and incomplete combustion,leading to enhanced oxidation reactivity.

Molecular Reactivity and Interface Stability Modification in In-Situ Gel Electrolyte for High Performance Quasi-Solid-State Lithium Metal Batteries

Quasi-solid-state lithium metal battery is a promising candidate for next generation high energy density and high safety power supply.Despite intensive efforts on electrolytes,uncontrolled interfacial reactions on lithium with electrolyte and patchy interfacial contacts still hinder its practical process.Herein,we bring in rationally designed F contained groups into polymer skeleton via in-situ gelation for the first time to establish quasi-solid-state battery.This method achieves a capacity retention of 90%after 1000 cycles at 0.5C with LiFePO_(4)cathodes.The interface constructed by polymer skeleton and reaction with–CF_(3)lead to the predicted solid electrolyte interface species with high stability.Furthermore,we optimize molecular reactivity and interface stability with regulating F contained end groups in the polymer.Comparisons on different structures reveal that high performance solid stable lithium metal batteries rely on chemical modification as well as stable polymer skeleton,which is more critical to construct robust and steady SEI with uniform lithium deposition.New approach with functional groups regulation proposes a more stable cycling process with a capacity retention of 94.2%at 0.5C and 87.6%at 1C after 1000 cycles with LiFePO_(4) cathodes,providing new insights for the practical development of quasi-solid-state lithium metal battery.

Assembly-level analysis on temperature coefficient of reactivity in a graphite-moderated fuel salt reactor fueled with low-enriched uranium

To provide a reliable and comprehensive data reference for core geometry design of graphite-moderated and low-enriched uranium fueled molten salt reactors,the influences of geometric parameters on the temperature coefficient of reactivity(TCR)at an assembly level were characterized.A four-factor formula was introduced to explain how different reactivity coefficients behave in terms of the fuel salt volume fraction and assembly size.The results show that the fuel salt temperature coefficient(FSTC)is always negative owing to a more negative fuel salt density coefficient in the over-moderated region or a more negative Doppler coefficient in the under-moderated region.Depending on the fuel salt channel spacing,the graphite moderator temperature coefficient(MTC)can be negative or positive.Furthermore,an assembly with a smaller fuel salt channel spacing is more likely to exhibit a negative MTC.As the fuel salt volume fraction increases,the negative FSTC first weakens and then increases,owing to the fuel salt density effect gradually weakening from negative to positive feedback and then decreasing.Meanwhile,the MTC weakens as the thermal utilization coefficient caused by the graphite temperature effect deteriorates.Thus,the negative TCR first weakens and then strengthens,mainly because of the change in the fuel salt density coefficient.As the assembly size increases,the magnitude of the FSTC decreases monotonously owing to a monotonously weakened fuel salt Doppler coefficient,whereas the MTC changes from gradually weakened negative feedback to gradually enhanced positive feedback.Then,the negative TCR weakens.Therefore,to achieve a proper negative TCR,particularly a negative MTC,an assembly with a smaller fuel salt channel spacing in the under-moderated region is strongly recommended.

Computational Chemistry and Molecular Modeling Techniques for the Study of Micropeptin EI-964: Insights into Its Chemical Reactivity and Potential Pharmaceutical Properties

Micropeptin EI-964 is a cyclic peptide compound isolated from a marine cyanobacterium with potent inhibitory activity against serine proteases, particularly chymotrypsin and trypsin. It has shown promising activity against various cancer cell lines, making it a candidate for drug development. The unique structure and activity of Micropeptin EI-964 make it a promising lead compound for the development of novel serine protease inhibitors and anti-cancer drugs. Computational Chemistry and Molecular Modeling techniques can provide valuable insights into the chemical reactivity and pharmaceutical properties of Micropeptin EI-964, guiding the design and development of new compounds with enhanced bioactivity and improved drug-like properties.

Computational investigation on the molecular structure and chemical reactivity of a traditional Chinese medicine extract MK-1 molecule

MK-1 molecule(C_(16)H_(16)O_(2)),the simplest structure of vitamin K(VK)compound family,is an extract from traditional Chinese medicine Cymbopogon distans(Nees ex Steud.)Wats(Chinese name YunXiangCao),which has attracted a great deal of attention in recent years due to its antiasthmatic,antitussives and expectorant effects.To investigate the molecular structure and chemical reactivity of MK-1 molecule,computational investigations on six conformational minima structures were carried out at the MP2/6-311++G(2d,2p)level of theory.Several local reactivity descriptors including condensed Fukui function,average local ionization energy,and molecular electrostatic potential on each individual atom were determined to predict the intrinsic reactivity of MK-1 molecule.

甘露醇对草菇继代菌株生产性状和ROS清除能力的影响

【目的】研究甘露醇对草菇继代菌株的生产性状和活性氧(ROS)清除能力的影响,探索一种简便、有效的草菇退化菌种复壮方法。【方法】以笔者课题组前期获得的组织分离继代菌株T6、T12、T19为试验菌株,T6为连续继代6次,T12为连续继代12次,T19为连续继代19次;草菇原种V844(T0)为商业栽培种。将传统马铃薯葡萄糖琼脂培养基(PDA)中的葡萄糖替换为等质量的甘露醇,进行菌丝生理性状测定;在栽培基质中添加甘露醇,测定子实体农艺学性状;以硝基四氮唑蓝(NBT)染色、超氧阴离子(O_(2))、过氧化氢(H_(2)O_(2))含量反映活性氧(ROS)积累;采用实时荧光定量PCR(RT-qPCR)测定抗氧化酶基因表达量;利用试剂盒测定抗氧化酶活力;通过菌丝染色法测定细胞核数量和线粒体膜电位;利用高效液相色谱仪(HPLC)测定菌丝能量指标。【结果】甘露醇处理对未退化菌株T0、T6的影响不显著,但能有效恢复草菇退化菌株T12、T19的生产性状和ROS清除能力。甘露醇使T12、T19的菌丝生长速度分别提高31.46%、20.99%,菌丝生物量分别提高97.33%、76.36%;使T12的生产周期缩短12.24%,生物学效率提高17.97%,恢复至T0水平;并使退化严重、失去出菇能力的T19重新长出子实体。同时,甘露醇使T12、T19的Cu/Zn超氧化物歧化酶基因(Cu/Zn-sod)相对表达量分别上调24.64%和61.54%,Mn-sod2相对表达量分别上调19.76%和267.09%,谷胱甘肽过氧化物酶基因(gpx)相对表达量分别上调25.67%和55.82%,并使SOD活力分别提高10.79%和72.32%,GPX活力分别提高16.98%和103.85%;使T12、T19中的ROS积累量显著降低,T12、T19中的O_(2)含量分别下降35.96%和41.62%,H_(2)O_(2)含量分别下降14.44%和18.26%;并使T12、T19的细胞核数目和线粒体膜电位显著增加;使T12、T19中的ATP含量分别提高17.08%和14.55%,EC值分别提高4.52%和0.92%。【结论】甘露醇能显著提高草菇退化菌株T12、T19的抗氧化能力和线粒体功能,并有效恢复其生产性状。

血清PCT、CRP及IL-4水平预测小儿支原体肺炎病情严重程度的价值

目的:探讨血清降钙素原(PCT)、C反应蛋白(CRP)及白细胞介素-4(IL-4)水平预测支原体肺炎患儿病情严重程度的价值。方法:选取2019年1月—2023年1月淮安市第二人民医院儿科收治的102例支原体肺炎患儿作为研究对象,根据病情将患儿分为轻症组59例和重症组43例。比较两组临床资料及基质细胞衍生因子(CXCL12)、γ干扰素(IFN-γ)、硫化氢(H_(2)S)、超氧化物歧化酶(SOD)、基质金属蛋白酶-9(MMP-9)、PCT、CRP及IL-4水平,多因素分析采取非条件logistic逐步回归分析,采用ROC曲线分析PCT、CRP及IL-4水平对重症支原体肺炎的预测价值。结果:两组性别、年龄、病程及CXCL12、IFN-γ、H_(2)S、SOD、MMP-9水平比较,差异无统计学意义(P>0.05);重症组PCT、CRP、IL-4水平显著高于轻症组,差异有统计学意义(P<0.05)。logistic逐步回归分析结果显示,PCT、CRP及IL-4为重症支原体肺炎独立危险因素(P<0.05)。ROC分析显示,PCT、CRP及IL-4预测重症支原体肺炎的曲线下面积分别为0.896、0.851、0.787。结论:血清PCT、CRP及IL-4水平均参与支气管肺炎患儿的病情进展,且可作为重症支气管肺炎的诊断指标。

六味地黄丸治疗早发性卵巢功能不全模型小鼠的分子机制

背景:在临床上,大多数治疗早发性卵巢功能不全的方剂均以六味地黄丸为基础方演变而来,并且取得了较好的疗效。目前对六味地黄丸的实验研究大多为体内动物模型的形态学观察及生理生化指标的检测,而分子机制方面的研究报道较少。目的:探讨六味地黄丸治疗早发性卵巢功能不全的分子作用机制。方法:环磷酰胺120 mg/kg联合白消安12 mg/kg腹腔注射制备早发性卵巢功能不全小鼠模型,然后用六味地黄丸混悬液对早发性卵巢功能不全小鼠进行干预,干预12周采用ELISA法检测小鼠血清中促卵泡刺激素、促黄体生成素、雌激素、抗苗勒氏管激素、8-羟脱氧鸟苷、总抗氧化能力、活性氧水平;苏木精-伊红染色观察小鼠卵巢形态学改变;透射电镜观察小鼠卵泡颗粒细胞超微结构及颗粒细胞线粒体的凋亡情况;免疫组化法检测六味地黄丸对小鼠卵巢颗粒细胞中核受体转录辅激活因子(receptor gamma coactivator-1 alpha,PGC-1α)、线粒体转录因子A(mitochondrialtranscriptionfactorA,TFAM)的表达水平。结果与结论:①与模型组比较,实验组小鼠血清促卵泡刺激素、促黄体生成素、活性氧、8-羟脱氧鸟苷水平降低(P<0.05),雌激素、抗苗勒氏管激素、总抗氧化能力水平升高(P<0.05);②苏木精-伊红染色发现模型组小鼠卵巢组织中闭锁卵泡和黄体较多,个别可见次级卵泡,间质纤维化增生;实验组小鼠卵巢组织可见大量闭锁卵泡,黄体较少,边缘可见原始卵泡,次级卵泡较少,未见明显成熟卵泡;③透射电镜发现实验组小鼠卵巢颗粒细胞内细胞器较完整;④免疫组化结果显示,实验组小鼠卵巢组织PGC-1α的表达水平在第4周稍有升高至第8,12周无明显变化,与模型组有明显差异;实验组小鼠卵巢组织TFAM的表达水平在第4周时短暂升高,然后稍有所下降,但结果均与模型组有明显差异;⑤结果表明,六味地黄丸通过PGC-1α-TFAM-ROS信号通路在一定程度上抑制早发性卵巢功能不全小鼠卵巢颗粒细胞凋亡,从而改善卵巢的内分泌功能,提高机体抗氧化能力,减轻氧化应激损伤程度。

计及IGBT结温约束的光伏高渗透配电网无功电压优化控制策略

光伏电源参与配电网无功电压调节是提升光伏高渗透配电网运行经济性和可靠性的有效手段,但光伏电源提供无功支撑会使得光伏电源IGBT最大结温升高、结温波动加剧,进而影响光伏电源和配电网的安全稳定运行。为此,该文提出一种计及IGBT结温约束的光伏高渗透配电网无功电压优化控制策略。首先,利用CatBoost算法计算IGBT结温,提高了IGBT结温计算效率,避免了传统结温算法对IGBT热模型参数的依赖;然后,建立考虑IGBT结温约束的有源配电网多目标无功优化模型,利用二分法求解IGBT结温约束下的光伏电源最大输出功率,实现了IGBT结温约束向二阶锥约束的转换;最后,利用IEEE33节点典型配电系统验证了所提策略在光伏高渗透配电网无功电压优化、光伏电源运行可靠性提升方面的有效性,并提出了综合考虑配电网网损、光伏电源可靠性的光伏电源IGBT结温限值整定原则。

考虑光伏电源可靠性的新能源配电网数据驱动无功电压优化控制

充分挖掘分布式光伏电源的无功支撑能力,有助于解决光伏高比例接入带来的配电网电压波动、电压越限以及新能源消纳等问题,但光伏电源无功输出会造成其功率器件结温越限或剧烈波动,严重威胁到光伏电源的可靠运行。为此,提出考虑光伏电源可靠性的新能源配电网数据驱动无功电压优化控制策略。首先,提出一种基于数据驱动的光伏电源可靠性评估方法,该方法采用XGBoost机器学习模型计算IGBT结温,提高了IGBT结温计算效率,避免了评估精度对IGBT参数的依赖;进而建立考虑光伏电源可靠性的配电网无功电压优化模型,将IGBT结温均值和结温波动引入模型优化目标;然后,将该模型进行马尔可夫决策过程转化,并基于深度确定性策略梯度强化学习算法完成智能体训练;最后,通过IEEE33节点系统验证所提策略在无功电压快速优化和光伏电源可靠性提升方面的优势。

Pu在膨润土层中的反应性迁移模拟研究(2)——Pu的种态分布及反应性迁移分析

为评估柯尔碱膨润土工程屏障材料的安全性能,采用考虑渗流扩散、溶解-沉淀、表面配位吸附、放射性衰变等多过程动态耦合的反应性迁移模拟方法,综合运用TOUGHREACT等程序开展了Pu在柯尔碱膨润土层中反应迁移的数值模拟,结合地下水-膨润土体系演化模拟分析了Pu的种态分布特征,叠加表面配位模型预测分析了Pu的长期迁移规律。结果表明:地下水中Pu主要以难迁移的Pu(OH)_(4)(aq)形式存在;由于膨润土的低渗透性和强吸附性,正常情景下Pu的扩散范围很小而将长期滞留于1 m厚膨润土中;在忽略强吸附阻滞作用的保守情景下,Pu在渗流作用下可扩散迁移出膨润土层;考虑到长时间尺度下不可避免存在的不确定性,建议重视渗流扩散为主导的其他过程和情景研究。

反应堆瞬时短周期与反应性引入速率约束问题研究

核反应堆在反应性引入过程中会出现瞬时短周期现象,可能触发周期保护系统,从而出现非必要停堆问题。瞬时短周期受反应性引入速率影响较大,但同时与当前缓发中子先驱核浓度相关,一般难以量化。本文从点堆方程出发,基于两次保守假设,剥离出缓发中子先驱核浓度因素,推导出了简洁的瞬时短周期与反应性引入速率约束公式;并验证在该反应性速率约束下,瞬时短周期永远大于目标周期值,可以避免意外触发周期保护问题,为反应堆运行中的控制棒提升速率约束提供了理论依据。

药型罩形状对活性聚能侵彻体成型的影响

结合理论与数值模拟,对3种不同形状药型罩活性聚能侵彻体的成型行为开展了研究.数值模拟结果表明,在聚能效应下,球缺罩和大锥角圆锥罩形成尾部带有碎片云的类杆状活性聚能侵彻体,而小锥角圆锥罩则形成活性射流.相比于活性射流,类杆状活性聚能侵彻体速度较低,但凝聚性较好.进一步结合活性材料反应动力学方程,对活性聚能侵彻体成型激活反应行为进行分析.分析结果表明:活性射流激活区位于杵体外壁、射流头部和轴线附近;随炸高增加,激活区内活性材料反应不断加剧,特别是射流头部和轴线附近材料的反应,将导致活性射流膨胀发散,不利于侵彻;而类杆状活性聚能侵彻体激活区域主要集中在尾部碎片区和杆尾中心部位,化学反应对其影响相对较小.