Acid-pickling plates and strips speed control system by microwave heating based on self-adaptive fuzzy PID algorithm

Double self-adaptive fuzzy PID algorithm-based control strategy was proposed to construct quasi-cascade control system to control the speed of the acid-pickling process of titanium plates and strips. It is very useful in overcoming non-linear dynamic behavior, uncertain and time-varying parameters, un-modeled dynamics, and couples between the automatic turbulence control (ATC) and the automatic acid temperature control (AATC) with varying parameters during the operation process. The quasi-cascade control system of inner and outer loop self-adaptive fuzzy PID controller was built, which could effectively control the pickling speed of plates and strips. The simulated results and real application indicate that the plates and strips acid pickling speed control system has good performances of adaptively tracking the parameter variations and anti-disturbances, which ensures the match of acid pickling temperature and turbulence of flowing with acid pickling speed, improving the surface quality of plates and strips acid pickling, and energy efficiency.

Does acid pickling of Mg-Ca alloy enhance biomineralization?

The mechanical and physical properties of biodegradable magnesium(Mg)alloys make them suitable for temporary orthopaedic implants.The success of these alloys depends on their performance in the physiological environment.In the present work,surface modification of Mg-Ca binary alloy by acid pickling for better biomineralization and controlled biodegradation is explored.The corrosion rates of nitric and phosphoric acid treated samples were analysed by conducting electrochemical corrosion tests.In vitro degradation behaviour was studied using immersion test in simulated body fluid(SBF).The sample surfaces were characterized using scanning electron microscope(SEM),energy dispersive X-ray spectroscopy(EDS),Fourier transform infrared spectroscopy(FTIR)and X-ray photoelectron spectroscopy(XPS).It is seen that acid pickling leads to significant improvement in biomineralization and develop in situ calcium phosphate(Ca P)coating on the sample surfaces.In addition,the treated samples recorded a reduced degradation rate in the SBF compared to untreated samples.Thus,acid pickling is suggested as an effective surface treatment method to tailor the biomineralization and degradation behaviour of the Mg-Ca alloy in the physiological environment.

A new acid pickling process for copper alloys

The cleaning process of removing oxides on the surface of copper alloy sheetswas investigated systematically. Through optimizing, a perfect process was selected that is fit forremoving oxides on the surface. By acid pickling, all kinds of copper oxides are removedcompletely, furthermore, no poisonous gases are given out and a smooth and clean surface of copperalloys is obtained. At present, the process is applied successfully in the copper-processingindustry.

Macroscopic,thermodynamic,kinetic and microscopic study of nitric acid pickling of Elektron 21(EV31A)magnesium alloy

The study of pickling of the EL21T6 substrate in a nitric acid bath firstly provided knowledge of the influence of the different experimental parameters(concentration of acid,temperature and stirring of the solution)in relation to the etching rate.This experimental part led to the choice of standard pickling(T_(bath)=25℃,moderate stirring(250 rpm),[HNO_(3)]=1.20 mol/L,duration of 2 min)so as to obtain constant removal of material,even after several uses of the pickling bath.SEM observations also confirmed that in these operating conditions,pickling concerns both the grains of the matrix and the precipitates of type Mg3(Nd,Gd),leading to uniform removal of material from the surface.Working from a number of assumptions,thermodynamic and chemical kinetic studies then allowed a pickling mechanism to be proposed and led to obtaining values for the corresponding kinetic parameters(order of reaction,constant of mean rate,activation energy)to be obtained.

Application of on-line quality control for salvianolic acid B by near infrared spectroscopy

OBJECTIVE: To study and establish quality con-trol model of the Salvianolic Acid B by Near In-frared Spectroscopy (NIRS), and to realize on-line quality control of extracting and purifying proc-esses of industrial scale herbal product manu-facturing. METHOD: NIR chromatography was obtained from on-line NIR detection of extract-ing process and purifying process. HPLC analysis was carried out to determine the con-tents of salvianolic acid B. Partial Least Squares Regression (PLS) was used to establish the model between the information between NIRS and HPLC. RESULTS: For extracting model: the optimum Near Infrared (NIR) wavelength range was 9815- 5430cm-1, R=0.9784, RMSEC=0.258;for puri-fying model: the optimum NIR wavelength range was 9815-5430cm-1, R=0.9776, RMSEC=4.02. The average relative error was <5%. CONCLUSION: NIR technique is applicable for on-line quality control in production of salvianolic acid B.

On-Line Pyrolysis-Liquid Chromatography of （Meth-） Acrylic Acid in Waterborne Polymers Using Cryogenic Injection

Pyrolysis gas chromatography is not a comprehensive analysis method for the determination of acrylics. Polar acrylic monomers show low abundance by gas chromatography. Because of this, a home-made pyrolysis liquid chromatographic injector by means of cryogenic-focussing is developed to determine the presence and concentration of hydroxyl and carboxyl functional monomers present in water- and solvent-borne acrylics. We have shown the prove-of-principle of using cryogenic-focussing for UPLC （pyrolysis-ultra-performance liquid chromatography） injection.

Study on the Corrosion inhibitor and Fog Suppressor for Chemical Pickling of Iron and Steel

A new type of corrosion inhibitor and fog suppressor composed of Nitrogen-containing alkaloid,water-soluble butadiene lower polymer, and inorganic electrolyte has been investigated by gravimetric and electrochemical method. Effects or this chemicals on pickling rate and hydrogen penetration into iron and steel material in 50～150 g/L HCI or/and H2SO4 solutions at 20～70℃ temperature were examined. The amount of acid fog escaping from the surface of air-liquid was determined by chemical titration. The results indicate that the efficiency of inhibition and suppression depends on film properties by which mean a barrier film on the interface of bare mild steel/solution or an unsolvable liquid membrane as hydrophibic effect.In present work the film-forming mechanism by in situ and chemistry-mechanics effect is also discussed.

Multicomponent synthesis and designing of tetrasubstituted imidazole compounds catalyzed via ionic-liquid for acid steel corrosion protection:Experimental exploration and theoretical calculations

Five new tetrasubstituted imidazoles were designed with outstanding yields(83%-92%) in the occurrence of ionic liquid-based-pyridinium as a catalyst. The constructions of all synthesized derivatives were established by spectral tools and their purities were verified using thin-layer chromatography(TLC), displaying single-spot. The performance of corrosion protection of the prepared imidazole derivatives was examined theoretically and practically for acid steel corrosion. The experimental study was conducted by electrochemical(electrochemical impedance spectroscopy(EIS) and Tafel polarization(PPS)) tools.The findings from the used approaches concluded that the synthesized compounds were wellorganized inhibitors with an efficiency of 90.7%-98.5% at 50℃ and 0.7 mmol·L^(-1). The Tafel polarization results indicate the protective action of the additives was under mixed-monitoring. The additive adsorption on the electrode interface performed as a distinguished aspect for protection. The surface exploration on the blank and protected metal was completed by field emission scanning electron microscopy(FESEM). Computational studies by Monte Carlo(MC) simulation and quantum chemical calculation(DFT)were related to practical findings. The corrosion protection adsorption mechanism was reinforced by the preferable fitted Langmuir isotherm model. All findings from the applied-inspected approaches alternately confirm each other.

抑制活菌泡菜贮藏过程中品质劣变的研究

目的:研究活菌泡菜产品在贮藏流通过程中由微生物引起的产品品质变化,开发延长泡菜贮藏期的新方法。方法:对从泡菜中分离鉴定出来的8种乳酸菌,在不同pH培养基条件下检测各种乳酸菌生长速度。对8种乳酸菌进行产气测定。在发酵前添加泡菜汁、嗜酸乳杆菌、植物乳杆菌、木糖醇等,在不同温度条件下发酵和贮藏,对泡菜的色泽进行评分,对酸度、混浊度、挥发性物质进行测定。结果:在pH 4.5时,植物乳杆菌是优势菌,其次是短乳杆菌。在pH 4.0~3.0时,嗜酸乳杆菌是优势菌,其次是植物乳杆菌,主要产气菌是短乳杆菌、假肠膜明串珠菌、坏发酵乳杆菌。pH 4.0~4.5时,主要产气菌是短乳杆菌。在pH 3.5时,主要是坏发酵乳杆菌产气。在pH 3.0时,不容易产气。发酵前添加2 mL/L 1×10~5CFU/mL植物乳杆菌和20 mg/g木糖醇,可显著延长常温和低温下泡菜的贮藏期和货架期。结论:1×10~5CFU/mL植物乳杆菌和20 mg/g木糖醇处理,显著抑制常温贮藏泡菜的总挥发物积累,抑制泡菜的异硫氰酸烯丙酯、萘类积累,有利于维持原初气味特征。

传统酸菜发酵乳酸菌多样性及其功能特性研究进展

酸菜是以大白菜、卷心菜为主要原料,主要通过乳酸菌发酵而成的发酵食品,由乳酸菌发酵的酸菜具有独特的风味和积极的健康效果;乳酸菌也产生香气成分、细菌素和胞外多糖,这些成分有助于酸菜的质地、味道和保质期的提高;乳酸菌菌群结构交替变化,不同阶段发挥不同的作用,对酸菜品质、风味及安全性有很大的影响;酸菜富含蛋白质、碳水化合物、矿物质、维生素,因此食用酸菜有良好的益处;乳酸菌可以减少和降解酸菜中生物胺、亚硝酸盐和真菌毒素,从而降低了许多健康风险发生。基于此,本文综述了国内和国外酸菜乳酸菌的生化作用、多样性和益生性,乳酸菌分泌的代谢产物和风味,食用酸菜对健康的益处和酸菜存在的潜在风险,以期为传统发酵酸菜品质提升和筛选潜在益生菌菌株提供依据。

三次发酵技术提升工业化四川泡青菜风味的研究

目前工业化四川泡青菜大多采用两次发酵工艺结合脱盐、巴氏杀菌生产商品化酸菜的技术,以解决芥菜季节性收获和酸菜常年销售的问题。文章立足于工业化四川泡青菜的加工过程,研究了两次发酵后的半成品泡青菜经过脱盐后的风味损失,并设计了三次发酵进行风味优化。GC-MS与HPLC测定结果表明,脱盐后的泡青菜特征香味物质种类减少,相对含量降低,有机酸含量显著降低。经第3次发酵后,新增了酸类物质,赋予其草本香及酸香,并产生具有发酵果香和花香的己酸乙酯、辛酸乙酯,同时异硫氰酸酯类物质的相对含量降低,泡青菜的特征香味得到提升,自然发酵香味突出;有机酸总量提高12.69%,酸味更加柔和与醇厚;乳酸菌含量从234×10^(2)CFU/g提高到298×10^(3)CFU/g。该研究为工业化泡青菜自然发酵风味的提升提供了数据与工艺参考。

传统泡菜中高效降解核苷乳酸菌的筛选及其特性研究

高尿酸血症是一种因尿酸代谢障碍而引发的一种代谢性疾病。乳酸菌作为一类重要的益生菌可通过多种方式改善高尿酸血症。该研究旨在从泡菜中筛选能够高效降解核苷的乳酸菌并分析其特性。利用高效液相色谱法分析所筛选菌株的核苷降解能力,检测菌株对黄嘌呤氧化酶抑制作用、体外环境耐受性及抗生素敏感性。结果表明,短乳杆菌(Levilactobacillus brevis)SLlac-18对肌苷和鸟苷的降解率分别可达97.81%和97.89%;且对黄嘌呤氧化酶的活力具有一定抑制作用。此外,在pH 2.0的环境下,SLlac-18的存活率可达96%;在3 g/L胆盐环境下处理5 h条件下,SLlac-18的存活率可达96.33%;而在胃肠液环境中,SLlac-18同样表现较高的耐受性,存活率均在90%以上,且菌株对红霉素、氨苄西林等4种常见抗生素具有敏感性。短乳杆菌SLlac-18具有潜在降尿酸功能,且具有良好的益生特性,可以应用于高尿酸血症预防和辅助治疗中,具有一定应用价值。

长白山区发酵酱菜中高产胞外多糖乳酸菌的筛选及多糖抗氧化性分析

本研究旨在从发酵酱菜中筛选高产胞外多糖的乳酸菌,并探究其多糖的抗氧化性,以期寻找一种天然来源的、安全的抗氧化剂。从吉林省延吉市采集的300余份特色发酵酱菜中分离出160株乳酸菌(lactic acid bacteria,LAB),根据菌落产粘法筛选出10株产胞外多糖(Exopolysaccharides,EPS)的乳酸菌,进一步以胞外多糖产量较高的菌株A63、A120、A128作为目的菌株提取粗多糖,分离提取出的EPS产量分别为0.806、0.663和0.630 g/L,经16S rDNA和pheS基因序列比对分析鉴定三株乳酸菌均为植物乳植杆菌。利用DPPH自由基、ABTS+自由基和OH自由基清除率为指标评估胞外多糖的体外抗氧化活性。结果表明,三株植物乳植杆菌的胞外多糖都具有一定的自由基清除能力,其中菌株A63所产胞外多糖浓度为10 mg/mL时,对DPPH、ABTS+和OH三种自由基的清除率分别为90.47%、51.67%和35.08%,显著高于同浓度下其他菌株胞外多糖的抗氧化能力(P<0.05),可以作为天然抗氧化剂的潜在来源。

基于两次发酵法遵义特色泡辣椒游离氨基酸组成的主成分分析及综合评价

为探究两次发酵技术对泡辣椒品质的影响,以两次发酵遵义特色泡辣椒为研究对象,通过测定分析其脆度、色泽、氨基酸态氮、游离氨基酸差异,并采用味道强度值(taste activity value,TAV)、主成分分析(principal component analysis,PCA)进行综合评价,明确泡辣椒中游离氨基酸的含量、组成与呈味的多样性。结果表明:4种泡辣椒(新鲜、传统自然一次发酵30 d、两次发酵、传统自然一次发酵150 d)中氨基酸态氮含量分别为0.05、0.17、0.24、0.18 g/100 g,两次发酵特色泡辣椒的氨基酸态氮含量最高,且脆度保持较好,色泽鲜红。在4个样品中分别检测出13、15、16、15种氨基酸,呈味特性表现为鲜味氨基酸>甜味氨基酸>苦味氨基酸,其中谷氨酸对泡辣椒风味的影响最大,TAV值为9.67~45.67。通过主成分分析提取3个主成分,累积方差贡献率高达98.584%,能较好地反映出样品中游离氨基酸的综合信息,其中谷氨酸、苏氨酸、缬氨酸、甲硫氨酸、异亮氨酸、组氨酸、精氨酸、甘氨酸、半胱氨酸、亮氨酸、酪氨酸对泡辣椒滋味影响程度最大,并由各个主成分的综合得分得到遵义特色泡辣椒综合得分最高。综合评价发现两次发酵遵义特色泡辣椒相较于新鲜与传统自然一次发酵泡辣椒中游离氨基酸的综合品质更好,此为泡辣椒发酵技术的改进及泡辣椒风味的人工控制提供理论基础。

泡椒汁中耐受辣椒素乳酸菌的筛选及其耐受性研究

为强化发酵生产泡椒提供耐受辣椒素的乳酸菌,在四川农家自制泡椒老卤水中筛选并鉴定出一株耐受辣椒素植物乳杆菌(Lactobacillus plantarum)Y-6,在0.5 g/L辣椒素下的相对生长率为(70.16±0.03)%;菌液电导率、核酸蛋白泄漏、菌体细胞超微结构测定结果表明,辣椒素通过破坏乳酸菌的壁膜结构延滞其生长;菌株Y-6在IC_(50)(0.571 g/L)辣椒素处理下仍能保持细胞形态相对完整,受辣椒素的抑制作用低于商用乳酸菌6239;RT-qPCR结果表明,Y-6通过调节usp等应激蛋白基因表达应对辣椒素引起的膜损伤;调节相容性溶质调控系统基因以及ABC转运蛋白渗透酶基因的表达维持菌体渗透压的平衡;通过提高糖酵解等与生长代谢相关基因表达,维持其在辣椒素环境中的生长代谢。菌株Y-6对辣椒素有较高的耐受性,可为发酵辣椒的工业化生产和菌株改良育种工作的开展提供理论依据。

不同乳酸菌接种发酵对泡白菜理化特征及风味的影响

为评估泡白菜中乳酸菌的发酵特性,以植物乳杆菌(Lactobacillus plantarum)PC295、肠膜明串珠菌(Leuconostoc mesenteroides)PC137、柠檬明串珠菌(Leuconostoc citreum)PC222、食窦魏斯氏菌(Weissella cibaria)PC311、清酒乳杆菌(Lactobacillus sakei)PC229、短乳杆菌(Lactobacillus brevis)PC330为发酵菌株,分析不同乳酸菌接种发酵对泡白菜pH、总酸、还原糖、微生物数量、有机酸、游离氨基酸、挥发性风味成分的影响。经6种乳酸菌接种发酵后,泡白菜的pH、还原糖、柠檬酸、苹果酸、游离氨基酸总量以及大肠杆菌数量均下降;不同种乳酸菌表现出不同的发酵性能,植物乳杆菌PC295和短乳杆菌PC330发酵速度快,还原糖消耗量和产酸量高,抑制大肠杆菌效果好;异型发酵菌株产较多的乙酸和乙醇。采用顶空固相微萃取-气相色谱-质谱联用技术共检出挥发性风味物质56种,所有泡菜组均以醇类化合物为主,主要包括乙醇、1-辛烯-3-醇、顺-2-戊烯-1-醇等;清酒乳杆菌PC229和短乳杆菌PC330发酵的泡白菜中,反,反-2,4-庚二烯醛、己醛等醛类化合物和乙酸的相对含量高于其他组;主成分分析结果显示,肠膜明串珠菌PC137和柠檬明串珠菌PC222发酵的泡白菜成熟后其挥发性风味相似。不同种乳酸菌在泡白菜发酵速度、风味类型和底物消耗上存在差异。研究结果为进一步开发白菜类泡菜发酵剂奠定了基础。

白云母矿石盐酸酸洗除钙试验研究

随着我国双碳政策落实,能源等高新领域得到快速发展,对锂、铷等金属的需求日益增加,白云母作为含锂、铷矿物之一得以重视。针对在硫酸熟化处理白云母矿时,主要杂质钙的存在会降低有效提取率的问题,提出采用盐酸酸洗对白云母矿石进行预先除钙。首先,从热力学角度分析了酸洗时白云母和方解石与盐酸的反应情况,结果表明,在酸洗温度范围内,白云母几乎不与盐酸发生反应;当温度高于30℃时,方解石与盐酸反应可以自发进行。其次,通过对酸洗温度、盐酸浓度、酸洗时间和液固比等工艺参数的影响进行研究,结果表明:在酸洗温度70℃、盐酸浓度0.5 mol/L、酸洗时间1.5 h、液固比1 mL/g的条件下,钙的去除率可达98.3%,而铷和锂的损失率分别低至2.3%和3.3%。通过盐酸酸洗可实现白云母矿石中钙的选择性脱除。通过对酸洗渣进行表征发现,酸洗后白云母矿石中方解石相消失,矿石主要由白云母和石英组成,同时,电子能谱分析图像显示钙的富集区域消失。在相同的熟化和水浸条件下,对比直接熟化和酸洗+熟化两种不同工艺获得的锂和铷的浸出率发现,对酸洗后的白云母进行熟化可使锂、铷的提取率提高约10%~20%。最后,通过酸洗液循环除钙试验验证,酸洗液经补酸后(调节pH值至0.3)可供循环3次使用,钙的去除率均保持在90%以上,避免了废水的大量产生。

酸洗槽酸雾挥发外溢控制方式改进

酸洗槽盐酸酸雾存在挥发外溢的问题,对常规酸洗槽进行改进。采用自动调整吸风电机频率和阀门开度,应用H形空腔和气帘设计,设置酸洗槽后挡板等方式进行试验。改进后,盖板关闭情况下,槽体周边酸雾质量浓度为0.055 mg/m^(3),酸雾吸风效果提高了95.3%,盖板打开情况下,槽体周边酸雾质量浓度为0.164 mg/m^(3),酸雾吸风效果提高了97.9%,均满足工作场所空气中盐雾浓度允许标准。

优势乳酸发酵菌株筛选、鉴定及对发酵萝卜风味品质的影响

[目的]筛选优良乳酸菌菌株以构建萝卜专用的泡菜发酵菌种。[方法]从不同地区收集萝卜老坛泡菜母水,采用稀释涂布法从泡菜母水中分离乳酸菌,通过生理鉴定、形态学鉴定(菌落观察和,革兰氏染色法)、16S rDNA基因测序和系统发育树构建确定种类并对其生长特性、耐受能力和风味物质进行检测。[结果]分离筛选结合生理鉴定共获得120株菌株,其菌落为圆形凸起,镜检呈杆状或球状且均为革兰氏阳性菌。进一步通过产酸能力测试获得15株产酸能力较强的菌株。分子鉴定表明,1株为芽孢杆菌属、13株为植物乳杆菌属,1株为戊糖片球菌属。对不同类型发酵菌株进行生长特性分析,发现菌株LA-8与LA-11的生长速度比其他菌株快;菌株LA-8的产酸能力强,耐10%盐和15%蔗糖。4株不同类型菌株均具有较强的降解亚硝酸盐能力。萝卜发酵初试试验表明,菌株LA-8和LA-11的发酵能力较强,产酸速度快。4株不同类型乳酸菌发酵萝卜所产生的挥发性物质存在差异。[结论]从不同地区萝卜老坛泡菜母水中筛选得到3个不同类型的优势发酵菌,可作为萝卜泡菜产业生产的菌种来源。

明串珠菌与乳植杆菌复合发酵对低盐泡萝卜品质的影响

为研究不同乳酸菌对泡萝卜品质的影响,采用肠膜明串珠菌(Leuconostoc mesenteroides)AP7、戊糖乳植杆菌(Lactiplantibacillus pentosus)LP10及AP7-LP10双菌复合制备泡萝卜,分析发酵过程理化指标、色差、质构特性变化和感官指标。结果表明:接菌组pH、还原糖含量下降速率和总酸、乳酸升高速率优于自然发酵组(P<0.05);接菌组亚硝酸盐含量低,无亚硝峰的出现,果胶酶活性保持较低水平;AP7-LP10组和AP7组L高于其余2组(P<0.05),褐变指数和多酚氧化酶活性保持在较低水平;发酵7 d,AP7-LP10组硬度(70.92±3.94 N)高于其他组(P<0.05);AP7-LP10感官评分最高(92±2.11)。综上,接种乳酸菌泡萝卜成熟快,安全性高,AP7-LP10双菌复合有助于提升泡萝卜品质。