Conversion of Pretreated Biomass into Levulinic Acid via Continuous Extraction at Atmosphere Pressure

Conversion of biomass to chemicals or fuels under mild condition is still a challenge. As a platform molecule for chemicals and fuels, levulinic acid （LA） has been prepared by lique-faction of biomass at high pressure. In order to carry out the conversion from wheat straw to LA at atmosphere pressure, continuous extraction of the reactive system by an organic solvent with a higher density than that of water was utilized for degradation of pretreated biomass. Yields of LA were measured by means of gas chromatography-mass spectrometry and nuclear magnetic resonance. The results revealed that a maximum yield of 30.66% of LA can be obtained from wheat straw. In addition, the effects of biomass pretreated conditions on the LA conversion have been studied. The study provides a new route to convert biomass to valuable chemicals at atmosphere pressure.

Measurement of Mass Transfer Coefficients and Their Modelling of Continuous Counter-Current Aqueous Two-Phase System in a Packed Extraction Column

Overall dispersed side volumetric mass transfer coefficients for protein and amino acids were measured in continuous countercurrent PEG4000/KHP aqueous two-phase systems in a 57mm I.D. packed extraction column. A model for overall dispersed side volumetric mass transfer coefficients was derived by describing the motion of the drops based upon Navier-Stokes equation combined with the relationship between mass transfer coefficients and the drop velocity. The model provides good predictions and can be successfully used in aqueous two-phase extraction. The average relative deviation between calculated values and experimental data ranges from 8% to 14%.

A Study on Continuous Extraction of Cadmium by Using Liquid Surfactant Membrane

Based on batch extraction, improved liquid-impeled loop reactor(LLR) was used in continuous pilot-plant extraction for cadmium recovery from aqueous wastes. It integrated emulsifying, extracting, separating and demulsifying. The results showed that the extracting efficiencies were better than those of batch one and surfactant concentration was decreased to 3.0 percent from 4.0 percent of batch extraction.

THE BIDIMENSIONAL EVOLUTIONARYBOUSSINESQ-STEFAN PROBLEM WITH CONTINUOUS EXTRACTION

In this paper we consider an evolutionary continuous casting problem with convection partial derivative + b(y) chi - Delta kappa(u) + (v) over right arrow .del u = 0 coupled with Stokes equation in the liquid phase partial derivative(t) (v) over right arrow - v Delta (v) over right arrow + del p = (f) over right arrow(u) The mixed boundary condition is put on temprature. The existence of a weak solution is obtained by using methods of regularization, temperature dependent penalty form in the Stokes equation and compact arguments.

PERFORMANCE OF THE CONTINUOUS AFFINITY-RECYCLE EXTRACTION PROCESS

The continuous affinity- recycle extraction (CARE) process is extended ic a system with ultrafiltration membranes. The mathematical model of the process is established by taking into account membrane rejections to the components in a crude mixture. The process performance, defined as concentration factor (CF ), purification factor (PF ) and recovery yield (REC), is analyzed by computer simulations. The results show that CF and REC increase, but PF decreases with the membrane rejection. It is likely that optimum operating conditions exist to give the best process performance because the increases in eluant and affinity-recycle flow rate improve REC but decrease PF.

Sinomenine Purification by Continuous Liquid-Liquid Extraction Process with Centrifugal Extractors

Continuous manufacturing is considered as one of the future trends of pharmaceutical engineering. In this work, continuous liquid-liquid extraction for sinomenine purification was realized with the usage of centrifugal extractors. Chloroform was used as the extractant because of the high distribution coefficient (>100). Higher extraction ratio can be obtained when using the centrifugal extractor of Model CWL50-N. The extraction ratio of the second-stage extraction was higher than that of the first-stage extraction. The extraction ratio of the second-stage countercurrent extraction was higher than that of second-stage cross-flow extraction. When chloroform phase was recycled for liquid-liquid extraction, the extraction ratio was also higher than 95%. This work can also be an example of continuous liquid-liquid extraction for the separation of other Chinese medicine components.

Rapid and Continuous Extraction of Methyl Red from Wastewater Using Counter Current Chromatography

A new prototype and simple low speed counter current chromatography (LSCCC) has been fabricated and a laboratory work has been carried out for rapid and continuous removal of methyl red from wastewater using xylene as an extractant. The distribution ratio (D) and percentage of recoveries were calculated. The optimum concentration for extraction of methyl red was in the range of 2 × 10-4 to 8 × 10-4 mol·L-1. Maximum extraction achieved at pH range of 2 to 4.5. Various dye concentrations and solvent effects were studied to optimized conditions. It was shown that when the ratio of the organic phase to aqueous phase increased to more than 3:1, the striping efficiency decreased sharply. The experiments were carried out for 5 times and the highest extraction achieved was 99.8 per cent by two-solvent system LSCCC in just 5 minutes. Real wastewater samples were analyzed and the efficiency of the technique was compared with liquid-liquid extraction (LLE). In practice it was shown that although both techniques are rapid, the efficiency of the LSCCC is much better than LLE.

Enhanced lithium leaching from lepidolite in continuous tubular reactor using H_(2)SO_(4)+H_(2)SiF_(6) as lixiviant

An acidic mixture of sulfuric and fluosilicic acid(H_(2)SO_(4)+H_(2)SiF_(6))was employed as lixiviant to enhance leaching of lithium from lepidolite.The H_(2)SiF_(6) was obtained as a byproduct of anhydrous hydrofluoric acid production,aiming to provide HF molecules.It was found that the HF molecules were the main reaction component and played a key role in strengthening the dissolution of lepidolite.Different factors,including mass ratio of ore/H_(2)SO_(4)/H_(2)SiF_(6),concentrations of H_(2)SO_(4) and H_(2)SiF_(6),leaching temperatures(40−80℃)and time(15−75 min),were investigated.Moreover,an efficient tubular reactor was employed to improve this acid leaching system.Under the optimal conditions(ore/H_(2)SO_(4)/H_(2)SiF_(6) mass ratio of 1:0.8:1.6,80 wt.% H_(2)SO_(4),15 wt.% H_(2)SiF_(6),80℃,15 min),97.9% of Li,96.4% of K,97.6% of Rb,96.7% of Cs and 81.4% of Al(mass fraction)were leached.Additionally,a two-step thermal process was proposed to remove fluorine of leaching slurry.This acid treatment using an acidic mixture of H_(2)SO_(4) and H_(2)SiF_(6) in a continuous tubular reactor shows potential as an alternative process to extract lithium from lepidolite.

Review of minimally invasive continuous glucose monitoring technology & instruments

Continuous blood glucose monitoring is important for the diagnosis,treatment,and study of diabetes. many organizations have been working on this subject in recent two decades. Glucose concentration in interstitial fluid is closely related to the blood glucose levels. Minimally invasive continuous blood glucose monitoring technology based on the glucose detection in interstitial fluid develops rapidly and gets more and more attentions from the patients and the doctors,due to its instantaneous real-time display of glucose level,"24/7"coverage,and the ability to characterize glycemic variability. According to the different detection methods,most of the continuous glucose monitoring technology could be divided into two kinds: subcutaneous implantation method and transdermal extraction method. This paper review s the recent development of minimally invasive blood glucose monitoring technology and instruments. The mainly remained challenges and related research directions are presented as well.

Screening and Verification of Genes Specifically Responding to Continuous Cropping Obstacle in Rehmannia glutinosa L.

Rehmannia glutinosa L.is one of the important medicinal crops in China.Continuous cropping obstacle severely restricts the yield and quality of R.glutinosa,but its molecular mechanism is still unclear.In this study,with widely-planted "Wen 85-5" as an experiment material,based on the digital gene expression profiling (DGE) data of previous five stress treatments (continuous cropping,phenolic acid,salt,drought and waterlogging) and the first cropping and continuous cropping treatments of R.glutinosa in five different periods (seedling period,elongation period,early expanding period,middle expanding period and later expanding period),80 candidate genes (|log 2 ratio|≥1,FDR <0.001) specifically responding to continuous cropping obstacle in R.glutinosa were screened.Functional analysis revealed that the differentially expressed genes were involved in the secretion and endocytosis of root cells,which may suggest that the recognition and absorption of allelopathic autotoxins by the roots of R.glutinosa is an important factor that restricts the development of roots in continuous cropping of R.glutinosa.In order to accurately lock genes specifically responding to continuous cropping obstacle in R.glutinosa,continuous cropping soil extract and ferulic acid and p-hydroxybenzonic acid were used to treat aseptic plantlets of R.glutinosa,respectively,and it was confirmed through qRT-PCR that the expression levels of some genes under phenolic acid treatment changed more severely than that under the continuous cropping soil extract treatment,and four key genes involved in the response of R.glutinosa to continuous cropping were finally locked.This study lays a foundation for further exploration of the molecular mechanism of continuous cropping obstacle.

Parameters of Exterior Ballistic Feature Points Extraction in Radar Measurement Data by EMD

The problem of measuring exterior ballistic feature points is always difficult to solve and it is essentiale on exterior ballistic measurement.By analysis of radar reflection characteristics and non-stationary echo signals of exterior ballistic feature points,the echo data of exterior ballistic feature points is measured by using the continuous wave radar.The parameters of feature points are extracted by the empirical mode decomposition method(EMD)of Hilbert-Huang transform(HHT)spectrum analysis technique.The radar echo signal model and EMD extraction model are established to analyze the exterior ballistic mutation point detection and EMD extraction method of aliasing echo signal.Typical feature point parameters of exterior ballistic in rocket flight tests are carried out and the effectiveness of the method is verified.A new method of measuring the parameters of exterior ballistic feature point is therefore presented.

A Novel Extraction Method of Baicalin from Radix Scutellariae

A novel extraction method of baicalin from radix scutellariae was explored in this study. Liquid-liquid continuous biphasic extraction was a new method, and showed the advantage of high extracting contents of total flavone compared with one of the traditional methods. The novel extraction method which is easy to operate and has good reproducibility was much more effective than the traditional one.

A Liquid Chromatography Assay for the Simultaneous Quantification of Piperacillin and Ciprofloxacin in Human Plasma and Dialysate in Critically Ill Patients Undergoing Continuous Renal Replacement Therapy

Piperacillin/tazobactam and ciprofloxacin are often used in combination as initial empiric anti-biotic therapy in critical ill patients. Especially in patients undergoing continuous renal replacement therapy (CRRT) the pharmacokinetics of antimicrobial agents can be highly variable. In order to avoid under- or overdosage of antibiotics therapeutic drug monitoring (TDM) is highly re-commendable. Based on two known HPLC assays for piperacillin a new method in combination with solid phase extraction (SPE) for the simultaneous determination of piperacillin and ciprofloxacin was developed. Method validation was performed according to the EMA guideline on validation of bioanalytical methods. The HPLC column used was a Perfect Bond ODS-HD C18 analytical column (100 mm × 4.6 mm i.d., particle size 5 μm), equipped with a guard column (10 mm × 4.6 mm, particle size 5 μm) containing the same packing material. Detection wavelength was set at 228 nm for piperacillin and benzylpenicillin was used as internal standard (IS). Ciprofloxacin was determined at two wavelengths (280 nm, 315 nm). This newly developed HPLC method in combination with SPE-extraction allows an accurate, precise, specific and efficient determination of piperacillin and ciprofloxacin in biological matrices. Results allow the calculation of all relevant pharmacokinetic data for critically ill patients undergoing CRRT and the optimization of dosing and TDM.

基于持续强化学习的自动驾驶赛车决策算法研究

赛道形状与路面材质变化对自动驾驶赛车的行为决策带来了严峻挑战。为应对道路间的动力学差异,本文提出一种基于持续强化学习(CRL)的高速赛车决策算法。该算法将不同道路看作独立任务。算法的第1训练阶段负责提取描述不同任务上赛车动力学的低维特征,从而计算出任务间的相似性关系。算法的第2训练阶段负责为策略学习过程提供2个持续强化学习约束:其一是权重正则化约束,策略网络中对于旧任务重要的权重将在新任务学习期间被限制更新,其限制力度由任务相似性自适应调节;其二是奖励函数约束,鼓励在新任务学习期间策略的旧任务性能不下降。设计不同任务排序下的赛车实验和持续强化学习评价指标以评估算法性能。实验结果表明,所提算法能在既不存储旧任务数据也不扩展策略网络的条件下获得比基准方法更出色的驾驶性能。

萃取装备在烯草酮连续化生产中的应用

连续化是化工生产发展方向,以烯草酮生产中涉及的液-液萃取分离过程为对象,针对液-液萃取分离体系中杂质种类、含量及分离特性,详细探究两相流动及传质特性,开发了高效萃取塔、管式萃取器和油水聚结分离材料等,并成功应用于烯草酮生产萃取分离工段,实现了其连续自动化生产。基于高效萃取装备解决了传统釜式生产存在的密闭性差、产品质量不稳定、废水量大、能耗高、安全性差等问题,推动了我国农药化工生产技术水平持续提升。

基于大语言模型增强表征对齐的小样本持续关系抽取方法

关系抽取作为自然语言处理的关键任务,对于深化语言理解、构建知识图谱以及优化信息检索系统具有重要作用。然而,由于新关系不断涌现且缺乏大量标注示例,传统的监督学习方法并不适合实际场景。尽管大语言模型的出现显著提升了许多自然语言处理任务的性能,但仍然无法直接有效地解决小样本持续关系抽取任务的挑战。为了充分利用大语言模型的语义知识来缓解灾难性遗忘与过拟合问题,提出了一种基于大语言模型增强表征对齐的小样本持续关系抽取方法LAFA,通过关系实例改写、语义扩充和关系增强表征等策略,在保持数据量和计算成本较低的同时,有效提升了模型对新关系的适应性和对旧知识的保持能力。在两个关系抽取数据集FewRel、TACRED上进行实验验证,与现有方法相比,LAFA在小样本持续关系抽取任务中展现出较好的效果,尤其在增量阶段取得了最佳的实验结果。通过消融实验进一步揭示了方法中各个模块对整体性能的显著贡献。LAFA的推理效率与开销远远低于现有的基于大语言模型的方法,并且具有很强的扩展性,能够适配多种语言模型。

不同作物土壤水浸提液对远志的化感效应

[目的]建立远志合理的耕作制度,筛选远志最佳的轮作作物。[方法]选取8种远志产地常种作物,研究不同作物土壤水浸提液对远志种子萌发及幼苗生长的影响。[结果]不同作物土壤水浸提液对远志种子萌发均有抑制作用,浸提液浓度越大,抑制作用越强,平均总抑制率从小到大依次是大豆、谷子、玉米、小麦、高粱、蓖麻、油葵、芝麻。不同作物土壤水浸提液对远志幼苗的生长大部分出现了促进作用,各处理浓度间相比表现为随着浓度的增大幼苗及根生长逐渐受到抑制。各处理远志幼苗和根的生长整体呈负相关;蓖麻、芝麻处理,远志苗高、根短;大豆、玉米和谷子处理,远志根长、苗低、生长差。大豆、玉米、小麦、高粱和谷子处理的根长和根重高于CK。远志幼苗POD活性除芝麻和蓖麻外均随着浓度的增大而增强,MDA含量整体呈现随着浓度的增大而增加的趋势,SOD活性则随着浸提液浓度的增大先增加后降低。[结论]综合生长指标和生理指标,大豆、玉米、小麦和谷子是比较适合远志的轮作作物。

缝洞型碳酸盐岩油藏注氮气提高采收率技术

哈拉哈塘奥陶系油藏是典型的缝洞型碳酸盐岩油藏,岩溶储层发育,储层储渗空间主要由大小不等的溶洞、溶蚀孔洞和裂缝组成,宏观上离散,局部连续,储集体空间多尺度,缝洞体空间形态及分布复杂。水驱是这类油藏最主要的开发方式,经过15 a开发,注水失效单井和单元逐年增多,水驱失效后,注气成为缝洞型碳酸盐岩油藏提高采收率的最重要手段,注气提高采收率技术在哈拉哈塘进行了现场试验和推广应用,并且建立了6因素注气选井标准,从岩溶背景、井储关系、钻揭深度、储量规模、生产动态及剩余油类型等6个方面选井,依据注气时机、注气方式、注气量、焖井时间及指示曲线等5个方面进行注气参数设计,取得了一些注气选井原则和注气参数设计的初步认识,以期为缝洞型碳酸盐岩油藏注气开发提供参考。

模块化连续手语识别算法及技术综述

手语是听障人士和其他人之间重要的沟通方式,但许多普通人看不懂手语,导致听障人士和普通人交流障碍.随着深度学习网络在连续手语识别方向的应用,算法大模型为复杂难懂的连续手语动作翻译成通俗易懂的文本语句提供了技术基础.但是连续手语识别仍然面临着冗余帧过多,空间特征提取和时间特征提取网络不平衡,手语语序与文本语序不匹配等诸多问题.因此,研究准确率高、耗时少、场景通用性高的连续手语识别算法成为计算机视觉领域的热点问题之一.本文首先分析单模态和多模态的连续手语识别框架,并重点阐述关键帧提取、特征提取、序列学习3个模块在连续手语识别中的作用,以及模块中所用网络的优势与不足,然后总结连续手语数据集以及识别结果的评价指标,最后阐述连续手语识别算法的难点并展望其未来的发展方向.

基于对比学习和焦点损失的持续关系抽取

持续关系抽取旨在训练模型从不断变化的数据流中学习新关系,同时保持对旧关系的准确分类.然而,由于神经网络的灾难性遗忘问题,模型在学习完新关系之后,对旧关系的识别能力往往会大幅度降低.为了缓解灾难性遗忘对模型性能的影响,本文提出了一种基于对比学习和焦点损失的持续关系抽取方法.首先,在训练集与其增强样本集的并集上训练模型,以学习新任务;其次,从训练集中,为每个新关系选取并存储记忆样本;然后,将激活集中的示例与所有已知关系原型进行对比,以学习新旧关系;最后,利用关系原型进行记忆再巩固,并引入焦点损失提高模型对相似关系的区分.在TACRED数据集上进行实验,结果表明本文方法能够进一步缓解灾难性遗忘问题,提升模型的分类能力.