Process Parameters Optimization of Laser Cladding for HT200 with 316L Coating Based on Response Surface Method

In order to improve the sealing surface performance of gray cast iron gas gate valves and achieve precise molding control of the cladding layer,as well as to reveal the influence of laser cladding process parameters on the morphology and structure of the cladding layer,we prepared the 316L coating on HT 200 by using Design-Expert software central composite design(CCD)based on response surface analysis.We built a regression prediction model and analyzed the ANOVA with the inspection results.With a target cladding layer width of 3.5 mm and height of 1.3 mm,the process parameters were optimized to obtain the best combination of process parameters.The microstructure,phases,and hardness variations of the cladding layer from experiments with optimal parameters were analyzed by the metallographic microscope,confocal microscope,and microhardness instrument.The experimental results indicate that laser power has a significant impact on the cladding layer width,followed by powder feed rate;scan speed has a significant impact on the cladding layer height,followed by powder feed rate.The HT200 substrate and 316L can metallurgically bond well,and the cladding layer structure consists of dendritic crystals,columnar crystals,and equiaxed crystals in sequence.The optimal process parameter combination satisfying the morphology requirements is laser power(A)of 1993 W,scan speed(B)of 8.949 mm/s,powder feed rate(C)of 1.408 r/min,with a maximum hardness of 1564.3 HV0.5,significantly higher than the hardness of the HT200 substrate.

LÉVY AREA ANALYSIS AND PARAMETER ESTIMATION FOR FOU PROCESSES VIA NON-GEOMETRIC ROUGH PATH THEORY

This paper addresses the estimation problem of an unknown drift parameter matrix for a fractional Ornstein-Uhlenbeck process in a multi-dimensional setting.To tackle this problem,we propose a novel approach based on rough path theory that allows us to construct pathwise rough path estimators from both continuous and discrete observations of a single path.Our approach is particularly suitable for high-frequency data.To formulate the parameter estimators,we introduce a theory of pathwise Itôintegrals with respect to fractional Brownian motion.By establishing the regularity of fractional Ornstein-Uhlenbeck processes and analyzing the long-term behavior of the associated Lévy area processes,we demonstrate that our estimators are strongly consistent and pathwise stable.Our findings offer a new perspective on estimating the drift parameter matrix for fractional Ornstein-Uhlenbeck processes in multi-dimensional settings,and may have practical implications for fields including finance,economics,and engineering.

Optimization and Characterization of Combined Degumming Process of Typha angustata L. Stem Fibers

Plant derived natural fibers have been widely investigated as alternatives to synthetic fibers in reinforcing polymers.Researchers over the years have explored many plant fibers using different extraction processes to study their physical,chemical,and mechanical properties.In this context,the present study relates to the extraction,characterization,and optimization of Typha angustata L.stem fibers.For this purpose,desirability functions and response surface methodology were applied to simultaneously optimize the diameter(D),linear density(LD);yield(Y),lignin fraction(L),and tenacity(T)of Typha stem fibers.Typha stems have been subjected to both alkali(NaOH)and enzymatic(pectinex ultra-SPL)treatments.Three levels of process variables including enzyme concentration(10,15,and 20 ml/L)and treatment duration(10,15,and 20 days)were used to design the experiments according to the factorial design.Experimental results were examined by analysis of variance and fitted to second order polynomial model using multiple regression analysis.The Derringer’s desirability function released that the values of process variables generating optimized diameter,linear density,yield,lignin ratio and tenacity are 20 ml/L and 20 days for concentration of pectinex ultra-SPL enzyme and treatment duration,respectively.Confirmation was performed and high degree of correlation was found between the experimental and statistical values.Moreover,the morphological structure has been investigated by the scanning electron microscope,showing a crenelated structure of ultimate fiber bundles of cellulose composing the Typha fiber.Compared to Typha stem non-treated fibers(TSNTF),Typha stem combined treated fibers(TSCTF),brings to improve mechanical properties.This change in mechanical properties is affected by modifying the fiber structure showing alpha cellulose of(66.86%)and lignin ratio of(10.83%)with a crystallinity index of(58.47%).

Study on the Interactivity of Controlled and Automatic Information Processing in L2 Reading

L2 reading is not only an important channel for people to obtain information and knowledge,but also the main way for people to learn a foreign language.Reading information processing can be divided into controlled processing and automatic processing.Controlled information processing is a conscious and resource-intensive processing model,while automatic information processing is an unconscious and automatic processing model.This study investigates the characteristics and interactivity of controlled and automatic information processing in L2 reading,and explores the roles of controlled and automatic information processing strategies in improving L2 reading ability.The findings are as follows:(a)controlled and automatic information processing is interactive in L2 reading;and(b)the uses of controlled and automatic information processing strategies are beneficial to the improvement of the reading ability of L2 learners.This study has important theoretical and practical value in improving the efficiency of L2 reading teaching and learning.

湿法热解法制备L-焦谷氨酸的工艺优化研究

采用湿法热解法,以L-谷氨酸为原料,探究L-焦谷氨酸的制备工艺条件。通过单因素和正交试验对反应的条件进行优化,确定了制备L-焦谷氨酸的最佳工艺条件是反应时间4 h、加水量15 g、反应温度150℃,此时所得L-谷氨酸的转化率为97.37%。这种方法是用水作为反应载体,无需催化剂与压力等条件,既节能减排,又产量高,为清洁高效生产L-焦谷氨酸提供了一定的理论指导和实验数据参考。

煤层气L型水平井电潜螺杆泵井清防砂工艺技术创新及应用

套管完井压裂投产的煤层气L型水平井出砂严重,倒置式电潜螺杆泵举升工艺受压裂砂影响故障频繁,影响了连续稳定排采,因此确定了倒置式电潜螺杆泵排采过程中由于压裂砂导致的故障点,并针对性创新应用了井筒内、导流罩及泵内清砂工艺技术,同时优化防砂管柱设计,确保了连续稳定排采。

大肠杆菌产L-酪氨酸发酵工艺优化

L-酪氨酸是一种重要的必需氨基酸,属于芳香族氨基酸,在医药、食品、化工中被广泛应用。该研究以基因工程菌大肠杆菌(Escherichia coli)TY03菌株为L-酪氨酸生产菌,通过单因素和响应面实验研究发酵过程中接种量、发酵温度、溶氧量、发酵pH值和发酵时间对L-酪氨酸产量的影响,确定适宜的发酵工艺。最终确定发酵过程中pH控制为6.8,溶氧31.2%,发酵温度35.8℃,在此条件下发酵24 h,L-酪氨酸产量最高达到42.0 g/L。该研究确定了菌株TY03产L-酪氨酸适宜的发酵工艺,同时为微生物发酵法生产L-酪氨酸提供了一定的理论基础。

L-茶氨酸口溶膜的制备及其成膜条件的优化

茶氨酸是茶叶中特征性的非蛋白质类氨基酸,具有抗应激、稳定情绪、改善睡眠、增强免疫力和抗炎等多种药理作用。试验旨在制备L-茶氨酸口溶膜,并评价其质量。采用流延法制备L-茶氨酸口溶膜,通过单因素试验法和正交试验法对制备所需的L-茶氨酸含量、羟丙基甲基纤维素含量、甘油含量、烘箱温度和干燥时间进行探索,优化成膜处方成分配比和制备条件。结果显示,L-茶氨酸口溶膜最佳配比为L-茶氨酸0.5 g、HPMC 1.8 g、甘油0.5 mL、钛白粉0.02 g与12 mL水混合,最佳干燥条件为60℃干燥100 min,其物理性能、L-茶氨酸含量及重量差异等指标均满足要求,有望为宠物临床用药提供数据支持。

L-酪氨酸连续发酵工艺研究

当前工业上用微生物发酵法生产L-酪氨酸的工艺中,基本都是前期向发酵罐内加入基础培养基,中后期再流加各类营养物质,虽然整个发酵过程中减少了取料和放料的操作,保证发酵中物料不被浪费,但是,随着流加物质的不断增加,发酵液体系不断扩大,该过程在发酵后期需要不断地人为调控发酵参数,而人为调控中,难以避免调控参数波动,并最终影响发酵结果。因此,实验采用高效连续发酵,该工艺可以大大提高菌体活力,并且有效延长产酸高峰期,为了优化L-酪氨酸的高密度连续发酵生产工艺,通过对大肠杆菌TYR-05发酵培养,考察了L-酪氨酸发酵过程并且分析了菌体量、产酸量、产酸效率、糖酸转化率的情况,确定L-酪氨酸高密度连续发酵过程中接种量、糖速率、糖耗量、底糖浓度等关键条件,以达到高密度连续发酵工艺控制条件优化。实验结果表明在5 L发酵罐中,选择30%的种子接种量,发酵起始时,底物氯化胆碱浓度为1 g/L并每4 h向罐内流加0.2 g/L的氯化胆碱,发酵至12 h时,底糖耗尽,开始以12 g/(L·h)的补糖速率向罐内提供葡萄糖,并在此时开始放液,放液速率为0.13 L/h,使得装液量恒定在20%左右,发酵25 h时开始流加复合营养液,发酵35 h时最高菌体OD_(600)达到65,产酸量为55.8 g/L,糖酸转化率为25.4%,为L-酪氨酸连续发酵工业化生产提供了重要参考。

ON DE FINETTI'S OPTIMAL IMPULSE DIVIDEND CONTROL PROBLEM UNDER CHAPTER 11 BANKRUPTCY

Motivated by recent advances made in the study of dividend control and risk management problems involving the U.S.bankruptcy code,in this paper we follow[44]to revisit the De Finetti dividend control problem under the reorganization process and the regulator's intervention documented in U.S.Chapter 11 bankruptcy.We do this by further accommodating the fixed transaction costs on dividends to imitate the real-world procedure of dividend payments.Incorporating the fixed transaction costs transforms the targeting optimal dividend problem into an impulse control problem rather than a singular control problem,and hence computations and proofs that are distinct from[44]are needed.To account for the financial stress that is due to the more subtle concept of Chapter 11 bankruptcy,the surplus process after dividends is driven by a piece-wise spectrally negative Lévy process with endogenous regime switching.Some explicit expressions of the expected net present values under a double barrier dividend strategy,new to the literature,are established in terms of scale functions.With the help of these expressions,we are able to characterize the optimal strategy among the set of admissible double barrier dividend strategies.When the tail of the Lévy measure is log-convex,this optimal double barrier dividend strategy is then verified as the optimal dividend strategy,solving our optimal impulse control problem.

L-缬氨酸发酵液活性炭脱色工艺优化研究

该文对经大肠杆菌发酵得到L-缬氨酸发酵液进行初步膜过滤,后使用活性炭进行脱色,以脱色率和L-缬氨酸保留率评价脱色效果。考察了4种不同型号的活性炭对L-缬氨酸的脱色效果,实验表明,选择元力HPC-07活性炭为L-缬氨酸脱色活性炭,脱色条件为活性炭用量2%、脱色温度65℃、发酵液pH 5.5、脱色时间30min。发酵液颜色由棕黄色变为澄清无色,且L-缬氨酸保留率高于98.0%,上述研究为企业生产高质量L-缬氨酸提供数据参考。

基于外部气相沉积的S+C+L波段低色散斜率大有效面积非零色散位移光纤的设计与制备

针对现有光纤无法满足宽带光密集波分复用系统传输和S+C+L波段粗波分复用的要求,设计了一种具有中心凹陷的三角形芯+环形的折射率剖面,利用外部气相沉积工艺制备了一种非零色散位移光纤,并通过调整第一芯层的相对折射率和第二芯层与第一芯层的半径比,探究了其对光纤衰减、色散斜率和有效面积等参数的影响。研究发现,当第一芯层的相对折射率逐渐增大且第二芯层与第一芯层半径比逐渐减小时,零色散波长和有效面积逐渐减小。当第一芯层的相对折射率在0.52%~0.53%,芯层半径比在2.6~2.7时,光纤的有效面积接近70μm^(2),零色散波长在1420 nm附近,在1550 nm波段的色散系数大于8 ps·nm^(-1)·km^(-1),色散斜率为0.059 ps·nm^(-2)·km^(-1),可以较好地抑制传输过程中光非线性效应,满足长途干线网与城域网的使用要求。

Optimization of Polysaccharides Extraction from Physalis alkekengi L.Peel and Its Effect on the Expression of Inflammation-Related Proteins in SW620 Cells

Objective:To establish an optimized aqueous extraction process for polysaccharides from Physalis alkekengi L.peel and to preliminarily explore its in vitro anti-inflammatory activity against colorectal cancer SW620 cells.Methods:A single-factor test combined with orthogonal test analysis was used to evaluate the effects of the material-to-liquid ratio,extraction temperature,and extraction time on the yield of polysaccharides from Physalis alkekengi L.peel.The antioxidant activity of the polysaccharides was assessed by analyzing their free radical scavenging ability in vitro,and the anti-inflammatory effect was evaluated using SW620 cells.Results:The optimal extraction conditions were a material-to-liquid ratio of m(g):V(mL)=1:30,an extraction temperature of 100℃,and an extraction time of 40 minutes,with a predicted polysaccharide yield of 25.7%.The polysaccharides from Physalis peruviana peel effectively scavenged DPPH,superoxide anion,and hydroxyl radicals.After treatment with Physalis peruviana polysaccharides,the levels of IL-1β,IL-18,and TNF-αin the cell culture medium were significantly reduced,and the phosphorylation level of P65 protein in SW620 cells was decreased.Conclusion:This extraction method is stable and reliable,and the prepared Physalis alkekengi L.polysaccharides exhibit significant in vitro antioxidant and anti-inflammatory activities.This study provides a theoretical basis for developing drugs for the prevention and treatment of colorectal cancer.

L-精氨酸发酵过程控制研究

为提高L-精氨酸的发酵产量,实现L-精氨酸的高效工业化生产,对产L-精氨酸的大肠杆菌发酵过程控制进行研究。通过调节葡萄糖与硫酸铵流加速度改善供氧策略,在连续补料的基础上,建立了溶氧反馈补料和pH反馈调节的过程调控方法。结果表明,与连续补料相比,溶氧反馈补料对L-精氨酸产量、糖酸转化率均明显提升,其中L-精氨酸产量为91.2g/L,提升了26.67%;糖酸转化率为46.65%,提升了23.97%。经多批次小试发酵验证,平均L-精氨酸产量为90.4g/L,平均糖酸转化率为47.02%。该研究为大肠杆菌高产L-精氨酸提供了一种有效的过程控制策略,也为L-精氨酸工业化生产奠定了理论基础。

基于化学模式识别的黄丝郁金醋炙前后HPLC指纹图谱研究

目的:建立黄丝郁金、醋黄丝郁金HPLC指纹图谱,并结合化学计量学探讨黄丝郁金醋炙前后化学成分的差异及潜在质量差异标志物。方法:收集15批四川产黄丝郁金药材并制备醋炙品,建立指纹图谱,进行相似度评价,采用SIMCA-P 14.1软件进行聚类分析、主成分分析、正交偏最小二乘判别分析。结果:建立了黄丝郁金、醋黄丝郁金指纹图谱,均确定了20个共有峰,并指认出2号峰为Bisacurone、3号峰为Bisacurone B、6号峰为双去甲氧基姜黄素、7号峰为去甲氧基姜黄素、8号峰为姜黄素、9号峰为莪术二酮、14号峰为芳姜黄酮、15号峰为吉马酮。相似度均≥0.939。聚类分析和主成分分析可基本上区分黄丝郁金、醋黄丝郁金,正交偏最小二乘判别分析共筛选出黄丝郁金醋炙前后7个质量差异标志物。结论:该研究建立的黄丝郁金、醋黄丝郁金HPLC指纹图谱结合化学计量学方法可用于探索黄丝郁金醋炙前后潜在质量标志物。

Research on Flexible Transfer Line Schematic Design Using Hierarchical Process Planning

Flexible transfer line(FTL)is now widely used in ma ny manufacturing domains to realize efficiently,high quantity and economic prod uction.These manufacturing domains include automobile,tractor,internal-combu stion engine,and so on.In today’s competitive business environment,it is vit ally important for machine tool manufacturers to design flexible transfer line m ore effectively and efficiently according to a wider variety of customer demand s.This paper proposes an approach to a bidding-based flexible transfer line sc hematic design system.By analyzing manual FTL design process,the architecture o f flexible transfer line schematic design system(FTLSDS)is established.The syst em consists:of four processes:part feature modeling,process planning,FTL fac i lity layout and FTL evaluation. For FTL schematic design.a five-level proces s planning strategy named hierarchical process planning method is proposed.This method includes selection of manufacturing feature machining operation;part se t-up planning,feature sequencing,operation sequencing and process plan genera ting.The major decision relies on setup planning.According to the proceeding o f the hierarchical process planning,the structure of reasoning is proposed base d on blackboard.Under this paradigm,a cooperative effort between a hybrid coll ection of knowledge sources is possible.Total reasoning task can be divided int o some subtasks,and recursive-reasoning system is formed.It is convenient for process planning with step-by-step solution.Meanwhile,the blackboard is use d as the global data exchange area during all reasoning process.By using modula r technology,special purpose machine tools can be designed more efficiently and rapidly.The framework of machine modular design system to support machine requ irement design for FTL is established.By synthesizing the FTL evaluation criter ia.five evaluation criteria of flexible transfer 1ine schematic design are take n into account.An exampie is supplied to demonstrate and verify the validity an d feasibility of flexible transfer line schematic design approach.

Extraction Process and Content Determination of Total Flavonoids in Ginkgo( Ginkgo biloba L. ) Leaves

[Objectives]This study was conducted to study the extraction process and the content determination of flavonoids in ginkgo( Ginkgo biloba L.) leaves.[Methods]Ethanol extraction and methanol extraction of total flavonoids in ginkgo leaves were studied,and the optimal extraction conditions for flavonoids were determined by orthogonal test; and with quercetin as reference substance,total flavonoid content in ginkgo leaves was determined by UV spectrophotometry.[Results]The optimal extraction process was 4 h of Soxhlet extraction with methanol; and the total flavonoid contents had a good linear relation in the range of 0. 006 5-0. 039 mg/ml( R^2= 0. 999 9),the average content was stabilized at 1. 135%,and the average recovery of the method was 102. 0%. [Conclusions]This study selected the optimal extraction process for total flavonoids in ginkgo leaves. The test method is simple with high accuracy and precision,and is suitable for the extraction and determination of total flavonoids in ginkgo leaves.

Maximum principle for anticipated recursive stochastic optimal control problem with delay and Lvy processes

In this paper, we study the stochastic maximum principle for optimal control prob- lem of anticipated forward-backward system with delay and Lovy processes as the random dis- turbance. This control system can be described by the anticipated forward-backward stochastic differential equations with delay and L^vy processes （AFBSDEDLs）, we first obtain the existence and uniqueness theorem of adapted solutions for AFBSDEDLs; combining the AFBSDEDLs＇ preliminary result with certain classical convex variational techniques, the corresponding maxi- mum principle is proved.

α-L-鼠李糖苷酶水解朝藿定C制备淫羊藿苷工艺研究

目的研究α-L-鼠李糖苷酶水解朝藿定C制备淫羊藿苷工艺。方法以缓冲液种类、pH值、温度、底物与酶用量比例、反应时间、底物质量浓度为影响因素,朝藿定C转化率、淫羊藿苷得率为评价指标,单因素试验优化制备工艺。再进行放大试验,柱色谱分离得到酶解产物,^(1)H-NMR、^(13)C-NMR对产物进行鉴定。结果最佳条件为磷酸盐缓冲液,pH值4.5,温度50℃,底物与酶用量比例1∶2,反应时间72 h,底物质量浓度2 mg/mL,朝藿定C转化率为88.68%,淫羊藿苷得率为92.65%。在底物质量浓度2 mg/mL、反应体系200 mL条件下,朝藿定C转化率均在88%以上,淫羊藿苷产率均在90%以上,而且几乎无副产物生成。结论该方法反应条件温和,底物质量浓度高,成本低,简便可靠,可为淫羊藿资源综合开发利用、淫羊藿苷绿色工业化生产提供基础。

Stability Estimation for Markov Control Processes with Discounted Cost

This article explores controllable Borel spaces, stationary, homogeneous Markov processes, discrete time with infinite horizon, with bounded cost functions and using the expected total discounted cost criterion. The problem of the estimation of stability for this type of process is set. The central objective is to obtain a bounded stability index expressed in terms of the Lévy-Prokhorov metric;likewise, sufficient conditions are provided for the existence of such inequalities.