基于模型预测控制的柴油加氢装置分馏单元产品质量控制优化

针对传统比例积分(PI)控制对过程复杂、系统强耦合的柴油加氢装置分馏单元的稳定时间和控制效果不佳的问题,基于某石化企业柴油加氢装置分馏单元原有PI控制方案,提出模型预测控制(MPC)协同PI控制方案,并探讨了该方案控制分馏单元的可行性及控制效果。结果表明:MPC协同PI的控制方案能够提高装置的动态性能;在汽提塔进料量和汽提蒸汽量波动的情况下,PI控制和MPC方案的震荡次数相近,但MPC方案的稳定时间和控制最大偏差均更小;对于±10%进料量的扰动,PI控制和MPC方案的最大温度相对偏差分别为3.48%和0.07%,稳定时间分别为3.5 h和1.5 h,绝对误差积分(IAE)评价值分别为7.30和0.23,说明MPC方案的控制效果比PI控制更优;同时,验证了MPC协同PI控制的可行性,表明MPC协同PI控制更适用于柴油加氢装置分馏单元的先进控制。

Best Bounds on Measures of Risk and Probability of Ruin for Alpha Unimodal Random Variables When There Is Limited Moment Information

This paper presents explicit formulae giving tight upper and lower bounds on the expectations of alpha-unimodal random variables having a known range and given set of moments. Such bounds can be useful in ordering of random variables in terms of risk and in PERT analysis where there is only incomplete stochastic information concerning the variables under investigation. Explicit closed form solutions are also given involving alpha-unimodal random variables having a known mean for two particularly important measures of risk—the squared distance or variance, and the absolute deviation. In addition, optimal tight bounds are given for the probability of ruin in the collective risk model when the severity distribution has an alpha-unimodal distribution with known moments.

Ammonium Metavanadate Fabricated by Selective Precipitation of Impurity Chemicals on Inorganic Flocculants

High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detector and imaging,large scale energy storage system.NH_(4)VO_(3)is usually produced by spontaneous crystallization from the aqueous solution due to its sharp dependence of solubility on the temperature.However,hazardous chemicals in industrial effluent,include phosphorate,silicate and arsenate,causing severe damage to the environment.In this work,these impurities are selectively precipitated onto inorganic flocculants,while the vanadate dissolved in an aqueous solution keeps almost undisturbed.Therefore,high purity NH_(4)VO_(3)is produced by the crystallization from the purified solution.By screening various flocculants and precipitating parameters,polyaluminum sulfate with an optimal amount of 50 g/L,is demonstrated to selectively remove phosphorate,silicate and arsenate,corresponding to the removing efficiency of 93.39%,97.11%and 88.31%,respectively.NH_(4)VO_(3)from the purified solution holds a purity of 99.21%,in comparison with 98.33%in the product from the crude solution.This purifying technology cannot only produce NH_(4)VO_(3)with high added value,but also reduce the environmental pollution of waste liquid.

Experimental verification of nanonization enhanced solubility for poorly soluble optoelectronic molecules

Solubility enhancement has been a priority to overcome poor solubility with optoelectronic molecules for solution-processable devices. This study aims to obtain experimental data on the effect of particle sizes on the solubility properties of several typical optoelectronic molecules in organic solvents, including the solubility results of 1,3-bis(9-carbazolyl)benzene(m CP), 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)ben zene(TPBi) and 2-(4-tert-butylphenyl)-5-(4-biphenyl)-1,3,4-oxadiazole(PBD) in ethanol and acetonitrile,respectively. Nanoparticles of m CP, TPBi and PBD with sizes from dozens to several hundred nanometers were prepared by solvent antisolvent precipitation method and their solubility were determined by using isothermal saturation method. The saturation solubility of nanoparticles of three kinds of optoelectronic molecules exhibited increase of 12.9%-25.7% in comparison to the same raw materials in the form of microparticles. The experimental evidence indicates that nanonization technology is a feasible way to make optoelectronic molecules dissolve in liquids with enhanced solubility.

垂直下降管内液膜沸腾蒸发及相界面波动研究

采用数值模拟的方法对垂直下降管内液膜沸腾蒸发流动和传热特性进行研究。分析入口雷诺数Re和热流密度的耦合作用对液膜流动和传热的影响,结果表明:壁面生成的汽泡呈现液滴状;大汽泡表面分割、脱离出小汽泡;汽泡生成、脱离强化了沸腾传热效率;热流密度越大,液膜表面的稳定性越差;Re的提高能够增强相界面稳定性;降膜沸腾传热方式的不同对传热系数影响很大;在计算工况范围内,绘制出传热模态分布图,为工程应用提供基础。

Ultrasonic diagnosis of biliary atresia: A retrospective analysis of 20 patients

AIM: To investigate the clinical value of ultrasono-graphic diagnosis of biliary atresia (BA), a retrospective analysis of the sonogram of 20 children with BA was undertaken. METHODS: Ultrasonography (US) was performed in 20 neonates and infants with BA, which was confirmed with cholangiography by operation or abdominoscopy. The presence of triangular cord, the size and echo of liver, the changes in empty stomach gallbladder and postprandial gallbladder were observed and recorded. RESULTS: The triangular cord could be observed at the porta hepatis (thickness: 0.3-0.6 cm) in 10 cases. Smaller triangular cord (0.2-0.26 cm) can be observed in 3 cases. The gallbladder was not observed in 2 cases, and 1 case showed a streak gallbladder without capsular space. The gallbladders of 15 cases were flat and small. The gallbladders of 2 cases were of normal size and appearance, however, there was no postprandial contraction. The livers of all cases showed hepatomegaly and hetreogeneous echogenicity. Statistical analysis was performed to compare the hepatomegaly and hetreogeneous echogenicity and the stage of hepatic fibrosis. CONCLUSION: The presence of the triangular cord atthe porta hepatis is specific. However, it is not the only diagnostic criterion, since flat and small gallbladder and poor contraction are also of important diagnostic and differential diagnostic significance. The degree of hepatomegaly and hetreogeneous echogenicity is proportional with liver fibrosis, and able to indicate the duration of course and prognosis.

直肠癌患者发生低位前切除综合征的相关危险因素

目的分析230例直肠癌患者术后排便功能变化,探索直肠癌保肛手术后患者发生低位前切除综合征(LARS)的相关危险因素。方法选取2013年1月—2017年12月在山西省人民医院行直肠癌低位前切除手术,术中遵循直肠全系膜切除术原则的患者。按手术时间顺序采用电话、当面随访等方式对研究对象的排便功能进行评估。根据患者LARS严重程度,分为有LARS组(轻度及以上症状)和无LARS组,比较两组患者临床资料的差异,探究发生LARS的危险因素。结果230例患者,有LARS组患者126例(54.8%),无LARS组患者104例(45.2%)。两组患者性别、N分期、肿瘤位置、预防性回肠造瘘及有无吻合口漏比较,经χ^2检验,差异有统计学意义(P<0.05)。多因素Logistic回归分析显示,女性[OR=2.301,95%CI(1.239,4.275)]、低位肿瘤[OR=0.410,95%CI(0.288,0.584)]及吻合口漏[OR=29.289,95%CI(1.045,82.533)]是直肠癌患者术后LARS评分的独立影响因素(P<0.05)。结论直肠癌患者术后LARS发生率高,N分期、预防性回肠造瘘对直肠癌患者术后LARS有影响;而女性、低位肿瘤和吻合口漏是其独立危险因素。

Room temperature non-balanced electric bridge ethanol gas sensor based on a single ZnO microwire

In this paper,ultra-long and large-scaled ZnO microwire arrays are grown by the chemical vapor deposition method,and a single ZnO microwire-based non-balanced electric bridge ethanol gas sensor is fabricated.The experimental results show that the gas sensor has good repeatability,high response rate,short response,and recovery time at room temperature(25℃).The response rate of the gas sensor exposed to 90-ppm ethanol is about 93%,with a response time and recovery time are 0.3 s and 0.7 s respectively.As a contrast,the traditional resistive gas sensor of a single ZnO microwire shows very small gas response rate.Therefore,ethanol gas sensor based on non-balanced electric bridge can obviously enhance gas sensing characteristics,which provides a feasible method of developing the high performance ZnO-based gas sensor.

关节镜下微创跟骨成形术治疗Haglund综合征的临床疗效

目的探讨关节镜微创跟骨成形术治疗Haglund综合征的临床疗效。方法选取2015年6月-2017年7月沧州市人民医院骨一科采用关节镜微创跟骨成形术治疗Haglund综合征的15例患者,于术前、术后3和12个月分别采用美国足踝外科协会(AOFAS)后踝关节评分及疼痛视觉模拟评分(VAS)评价临床效果,运用SPSS 22.0软件对数据进行分析。结果15例患者均获得随访,随访时间12~24个月,平均17个月。与术前比较,术后12个月AOFAS后踝关节评分明显高于术前和术后3个月,而VAS评分明显低于术前和术后3个月。结论关节镜微创跟骨成形术治疗Haglund综合征术创伤小、恢复快,临床效果显著。

Double-null divertor configuration discharge and disruptive heat flux simulation using TSC on EAST

The tokamak simulation code （TSC） is employed to simulate the complete evolution of a disruptive discharge in the experimental advanced superconducting tokamak. The multiplication factor of the anomalous transport coefficient was adjusted to model the major disruptive discharge with double-null divertor configuration based on shot 61 916. The real-time feed-back control system for the plasma displacement was employed. Modeling results of the evolution of the poloidal field coil currents, the plasma current, the major radius, the plasma configuration all show agreement with experimental measurements. Results from the simulation show that during disruption, heat flux about 8 MW m-2 flows to the upper divertor target plate and about 6 MW m-2 flows to the lower divertor target plate. Computations predict that different amounts of heat fluxes on the divertor target plate could result by adjusting the multiplication factor of the anomalous transport coefficient. This shows that TSC has high flexibility and predictability.

Research on Deformation Control Indicators and Standard of Urban Traffic Tunnel Construction Adjacent to High-rise Building

The biggest environmental problem caused by the construction of tunnels adjacent to high-rise buildings is the settlement of buildings.The paper analyzes the influence of tunnel excavation on the deformation of the superstructure and the deformation mode of the superstructure.It introduces the indicators and standards for the construction control of tunnel adjacent to the building at home and abroad.Combined with the Yuzhong tunnel project under construction in Chongqing,the main monitoring indicators and control standards of the Yuzhong Tunnel passing through the main buildings are given after comprehensive analysis and considerations,which provide a reference for the deformation control indicators of similar urban traffic tunnels adjacent to high-rise buildings.

Demonstration and Analysis of Urban Traffic Tunnel Expansion Project Adjacent to Buildings

With the increasing number of urban underground construction projects,the evaluation of the influence of tunnel expansion on building foundation is one of the important factors to be considered in the project.In this paper,the deformation of the upper structure and the deformation pattern of the upper structure were analyzed,and the two-dimensional finite element model was built based on the case of Chongqing Jiefangbei Underground Ring Road Expansion Project Scheme.Comparative analysis of the deformation and changes in stress of the two tunnel expansion construction schemes of full-frame support and bolt suspension was performed,and the safety,rationality and feasibility of the bolt suspension scheme was confirmed through project safety analysis.It is hoped that this paper will serve as a reference for similar projects in the safety control technology of tunnel construction process.

汽车发动机气门导管通用型装配工具设计及应用

目前,传统的发动机气门导管装配多采用手动人工方式,或设计专用的工具进行装配,装配效率较低,通用性较差;文章介绍了一种发动机气门导管通用型装配工具。

肛管直肠黑色素瘤10例临床分析并文献复习

目的探讨肛管直肠恶性黑色素瘤(ARMM)的临床病理特征及诊治方法。方法回顾性分析苏州大学附属第一医院2011~2021年间收治的ARMM10例并结合文献复习,对其临床资料、病理特点、治疗结果和预后情况进行探讨并总结诊治经验。结果10例ARMM患者中,男性4例,女性6例;年龄50~79岁,平均发病年龄(61.4±7.6)岁。患者临床表现多样,但以便血为主,缺乏特异性,所有患者术前行CEA,CA19-9定量检测结果均正常;10例患者中,9例行免疫组化染色,其中主要指标有S-100、HBM、MelanA、Ki-67,9例患者S-100均为阳性;HBM8例阳性;MelanA除4例未查外,4例阳性,1例阴性。9例患者Ki-67均为阳性,其中5例阳性区>50%。6例接受腹会阴联合肿瘤切除术(Miles术),4例接受经肛门直肠肿物切除术;5例术后接受综合治疗,1例术后因泌尿系转移行尿道切除术,4例术后未行辅助治疗。患者总体生存期5.5个月~108个月,平均生存(30.6±29.5)个月,中位生存期28.0个月。结论ARMM是一种临床上罕见且恶性程度极高的恶性肿瘤,临床表现不典型,主要通过病理活检来确诊,对于确诊患者行腹会阴联合切除是主要的手术方式,术后可以辅助放化疗和免疫治疗。

NLRP3 activation in macrophages promotes acute intestinal injury in neonatal necrotizing enterocolitis

Background Macrophages are involved in various immune inflammatory disease conditions.This study aimed to investigate the role and mechanism of macrophages in regulating acute intestinal injury in neonatal necrotizing enterocolitis(NEC).Methods CD68,nucleotide-binding oligomerization domain,leucine-rich repeat,and pyrin domain-containing 3(NLRP3),cysteine aspartate-specific protease-1(caspase-1),and interleukin-1β(IL-1β)in paraffin sections of intestinal tissues from NEC and control patients were detected with immunohistochemistry,immunofluorescence,and western blot.Hypertonic pet milk,hypoxia and cold stimulation were used to establish a mouse(wild type and Nlrp3^(-/-))model of NEC.The mouse macrophage(RAW 264.7)and rat intestinal epithelial cell-6 lines were also cultured followed by various treatments.Macrophages,intestinal epithelial cell injuries,and IL-1β release were determined.Results Compared to the gut“healthy”patients,the intestinal lamina propria of NEC patients had high macrophage infiltration and high NLRP3,caspase-1,and IL-1β levels.Furthermore,in vivo,the survival rate of Nlrp3^(-/-)NEC mice was dramatically improved,the proportion of intestinal macrophages was reduced,and intestinal injury was decreased compared to those of wild-type NEC mice.NLRP3,caspase-1,and IL-1β derived from macrophages or supernatant from cocultures of macrophages and intestinal epithelial cells also caused intestinal epithelial cell injuries.Conclusions Macrophage activation may be essential for NEC development.NLRP3/caspase-1/IL-1β cellular signals derived from macrophages may be the underlying mechanism of NEC development,and all these may be therapeutic targets for developing treatments for NEC.

Kinetic and mechanism of the reaction between Cl and several mono-methyl branched alkanes

Branched alkanes are ubiquitous in the troposphere and play an important role in the chemical processes.In this work,the rate constants and products for the reaction of Cl atoms with 3-methylhexane and 2-methylheptane were measured at room temperature(298±0.2K)and atmospheric pressure using a conventional relative rate method.The rate constants of 3-methylhexane and 2-methylheptane in units of cm~3/(mol·sec)are(3.09±0.31)×10^(-10)and(3.67±0.40)×10^(-10),respectively.Furthermore,the corresponding atmospheric lifetime of the studied branched alkanes with Cl was 6.92-89.90 hours and 5.82-75.69 hours,respectively.The estimated atmospheric lifetimes indicated that the reaction with Cl atoms could be the most important atmospheric degradation pathway for 3-methylhexane and2-methylheptane.Primary gas-phase products of the reactions were identified and quantified,and particle-phase products were also obtained.The atmosphere oxidation mechanism of Cl atoms with 3-methylhexane and 2-methylheptane is proposed.The SOA yields of 3-methylhexane and 2-methylheptane from the reaction of Cl atoms were determined to be7.96%±0.89%and 13.35%±1.50%respectively.Overall,the results reveal that the primary loss process of branched alkanes is the reaction with Cl atoms,which impacts its degradation on a regional scale.

Light absorption properties and potential sources of brown carbon in Fenwei Plain during winter 2018–2019

A distinctive kind of organic carbon aerosol that could absorb ultraviolet-visible radiation is called brown carbon(Br C),which has an important positive influence on radiative budget and climate change.In this work,we reported the absorption properties and potential source of Br C based on a seven-wavelength aethalometer in the winter of 2018–2019 at an urban site of Sanmenxia in Fenwei Plain in central China.Specifically,the mean value of Br C absorption coefficient was 59.6±36.0 Mm^(-1) at 370 nm and contributed 37.7%to total absorption,which made a significant impact on visibility and regional environment.Absorption coefficients of Br C showed double-peak pattern,and Br C had shown small fluctuations under haze days compared with clean days.As for the sources of Br C,Br C absorption coefficients expressed strong correlations with element carbon aerosols and primary organic carbon aerosols,indicating that most of Br C originated from primary emissions.The linear correlations between trace metal elements(K,As,Fe,Mn,Zn,and Pb)and Br C absorption coefficients further referred that the major sources of Br C were primary emissions,like coal burning,biomass burning,and vehicle emissions.The moderate relationship between Br C absorption coefficients and secondary organic aerosols suggested that secondary production of Br C also played an important role.The 120 hr backward air mass trajectories analysis and concentration-weighted trajectories analysis were also used to investigate potential sources of Br C in and around this area,which inferred most parts of Br C were derived from local emissions.

Ultrasound-triggered piezocatalytic composite hydrogels for promoting bacterial-infected wound healing

Wound healing has become one of the basic issues faced by the medical community because of the susceptibility of skin wounds to bacterial infection.As such,it is highly desired to design a nanocomposite hydrogel with excellent antibacterial activity to achieve high wound closure effectiveness.Here,based on ultrasound-triggered piezocatalytic therapy,a multifunctional hydrogel is designed to promote bacteria-infected wound healing.Under ultrasonic vibration,the surface of barium titanate(BaTiO_(3),BT)nanoparticles embedded in the hydrogel rapidly generate reactive oxygen species(ROS)owing to the established strong built-in electric field,endowing the hydrogel with superior antibacterial efficacy.This modality shows intriguing advantages over conventional photodynamic therapy,such as prominent soft tissue penetration ability and the avoidance of serious skin phototoxicity after systemic administration of photosensitizers.Moreover,the hydrogel based on N-[tris(hydroxymethyl)methyl]acrylamide(THM),N-(3-aminopropyl)methacrylamide hydrochloride(APMH)and oxidized hyaluronic acid(OHA)exhibits outstanding self-healing and bioadhesive properties able to accelerate full-thickness skin wound healing.Notably,compared with the widely reported mussel-inspired adhesive hydrogels,OHA/THM-APMH hydrogel due to the multiple hydrogen bonds from unique tri-hydroxyl structure overcomes the shortage that catechol groups are easily oxidized,giving it long-term and repeatable adhesion performance.Importantly,this hybrid hydrogel confines BT nanoparticles to wound area and locally induced piezoelectric catalysis under ultrasound to eradicate bacteria,markedly improving the therapeutic biosafety and exhibits great potential for harmless treatment of bacteria-infected tissues.

Exopolysaccharides from lactic acid bacteria,as an alternative to antibiotics,on regulation of intestinal health and the immune system

Over-use or misuse of antibiotics in livestock and poultry production contributes to the rising threat of antibiotic resistance in animals and has negative ecological effects.Exopolysaccharides from lactic acid bacteria(LAB-EPS)are a class of biological macromolecules which are secreted by lactic acid bacteria to the outside of the cell wall during their growth and metabolism.Numerous studies demonstrated that LAB-EPS have anti-inflammatory and antimicrobial activities and are able to regulate intestinal health and the immune system in livestock.They are biodegradable,nontoxic and bio-compatible,which are considered as ideal alternatives to antibiotics.This review aims to discuss and summarize recent research findings of LAB-EPS on regulation of intestinal health and the immune system in animals,and thus provide scientific justification for commercial applications of LAB-EPS in livestock.

Corrigendum to“Ultrasound-triggered piezocatalytic composite hydrogels for promoting bacterial-infected wound healing”[Bioact.Mater.24(2023)96-111]

The authors regret<that the SEM image of G12 hydrogel in Fig.2f was wrongly used during the assembly of Fig.2.The authors had checked the original data and replaced Fig.2f with the correction image.This error does not affect the scientific conclusions of the article in any way.>.The authors would like to apologise for any inconvenience caused.