超临界流体增强溶液分散度法制备阿莫西林缓释微囊

采用超临界流体增强溶液分散度法,对制备阿莫西林-乙基纤维素-卡波谱缓释微囊进行了初步研究,探索了制备微米级缓释药物微囊的新方法。在对制备乙基纤维素空白微粒影响因素研究的基础上,选择了较为适合的工艺参数:CO2流速0.42 m/s,温度40℃,压力9.0或12.0 MPa。在2种压力下分别得到平均粒径为5.48μm和2.85μm的药物微囊,其载药量为9.53%和9.70%,同时还考察了制得微囊药物的释放度曲线,结果表明阿莫西林微囊具有明显的缓释效果。超临界流体增强溶液分散度法是制备微米级药物微囊的极有前途的方法。

基于超临界流体强化溶液快速分散技术的冬凌草甲素脂质体口服制剂制备工艺研究

目的:优化超临界流体强化溶液快速分散技术(SEDS)制备冬凌草甲素脂质体口服制剂(ORI-LIP)的工艺,并探讨其与常规脂质体制备技术的优势。方法:以粒径为评价指标,采用正交试验考察压力、温度、进样流速对SEDS制备ORI-LIP的影响。同时,采用薄膜分散法和逆向蒸发法制备ORI脂质体,比较3种方法所制脂质体的粒径、包封率、载药量及稳定性(6个月加速试验),并比较ORI原料药与3种脂质体的体外溶出行为的差异。结果:优化后的ORI-LIP SEDS制备工艺条件为温度50℃,压力18MPa,进样流速1 m L/min;与薄膜分散法和逆向蒸发法比较,以SEDS技术制备的脂质体的粒径[(147.4±4.8)nm]更小,包封率(67.8%)、载药量(7.8%)及稳定性(粒径略有增加,包封率仅降低4.4%)都更高。体外溶出试验结果显示,与原料药比较,各脂质体的释药速率缓慢且持久,且累积释放度更高;其中,SEDS技术制备的ORI-LIP在24 h时达到溶出平衡,且累积溶出度最高,达到67.2%。结论:SEDS制备的ORI-LIP粒径小,包封率、载药量较高,稳定性较好,能显著提高药物的体外溶出度;该技术与常规脂质体制备技术相比有一定的优势。

超临界流体技术制备5-氟尿嘧啶聚乳酸微球

目的 以5-氟尿嘧啶（5-Fu）为模型药物，制备氟尿嘧啶聚乳酸微球。方法 采用超临界流体强制分散溶液技术，将5-Fu微粒化，并制备5-Fu聚乳酸微球。通过扫描电镜、激光粒度仪检测微球外形及粒径分布；气相色谱法测定二氯甲烷的残留量；恒温振荡透析法检测药物的释放度。结果 25℃时，微粒化后5-Fu的乙醇饱和溶液浓度为6．43mg·ml^-1，较原料药的2．32mg·ml^-1有显著提高；所制备载药微球球形较好，表面光滑。粒径分布窄，粒径范围0．615—1．990μm，平均粒径为0．980μm；二氯甲烷残留量为0．0046％；微球载药量为2．6％。包封率为17．8％，药物释放呈缓释模式，无突释效应。结论 超临界流体强制分散技术是制备5-Fu聚乳酸微球的可行方法。

锂离子电池负极分散工艺研究

采用超高黏度搅拌工艺制备锂离子负极浆料,防沉降剂分两步加入进行分散,并与流体分散工艺得到的浆料对比浆料黏度、颗粒度、固含量、膜片电阻率、粘接力及电芯性能等。采用超高黏度搅拌工艺制备的浆料,黏度变化更小、颗粒度更接近粉体颗粒度,与流体分散工艺相比,膜片电阻率低2.4 mΩ/cm,极片的粘接力高3.1 N,电芯以3 C在2.00~3.65 V充放电,循环200次的容量保持率高1.6%。

超临界流体技术制备5-氟尿嘧啶聚乳酸微球

目的：以5-氟尿嘧啶（5-Fu）为模型药物，制备氟尿嘧啶聚乳酸微球。方法：采用超临界流体强制分散溶液技术，将5-Fu微粒化，并制备5-Fu聚乳酸微球。通过扫描电镜、激光粒度仪检测微球外形及粒径分布；气相色谱法测定二氯甲烷的残留量；恒温振荡透析法检测药物的释放度。结果25℃时，微粒化后5-Fu的乙醇饱和溶液浓度为6．43mg·mL^-1，较原料药的2．32mg·mL^-1有显著提高；所制备载药微球球形较好，表面光滑，粒径分布窄，粒径范围0．615～1．990μm，平均粒径为0．980μm；二氯甲烷残留量为0．0046％；微球载药量为2．6％，包封率为17．8％，药物释放呈缓释模式，无突释效应。结论：超临界流体强制分散技术是制备5-Fu聚乳酸微球的可行方法。

超临界流体强化溶液快速分散技术制备三七皂苷脂质体性质研究

目的观察超临界流体强化溶液快速分散技术(SEDS)制备三七皂苷脂质体(PNS-Lip)的药剂学特征,并与常规脂质体制备方法进行比较。方法采用超临界流体强化溶液快速分散技术(SEDS)、薄膜分散法(TFD)、逆向蒸发法(RPE)制备PNS-Lip。透射电镜观察不同PNS-Lip外观形态;检测粒径与电位;超滤法测定包封率(EE)和载药量(DL);以药物泄漏率(LR)评价制剂稳定性;进行体外溶出实验检测。结果不同制备方法制得的PNS-Lip呈现出淡蓝色乳光,表面光滑,形态圆整,具有双层膜结构。与PNS-Lip-RPE比较,PNS-Lip-TFD及PNS-Lip-SEDS粒径、多分散系数(PDI)、Zeta电位降低,60、120、180、240、300、360 s LR降低,EE和DL升高(P<0.05,P<0.01);PNS-Lip-SEDS在420s LR降低(P<0.05)。与PNS-Lip-TFD比较,PNS-Lip-SEDS的粒径、PDI及Zeta电位降低,180、240、300、360、420 s LR降低,EE和DL升高(P<0.05,P<0.01)。PNS-Lip-RPE及PNS-Lip-TFD在初始阶段存在突释作用,随后持续缓慢释放;PNS-Lip-SEDS未发生突释现象,缓释作用更加明显,在48 h后达到溶解平衡。结论SEDS作为新型的制粒技术,与常规的脂质体制备方法相比具有一定的优势,该技术在纳米给药系统领域具有广阔的应用前景。

塔河常渣减黏裂化反应规律及生焦抑制方法研究

以塔河常渣(THAR)为研究对象,在不同的反应温度及反应时间下,进行减黏裂化反应,考察不同反应条件对产物分布及减黏油性质的影响。研究结果表明,随反应温度和反应时间的增加,减黏油的黏度逐渐降低,生焦率呈上升趋势。塔河常渣的沥青质含量极高,即使在较缓和的操作条件下,依然易产生大量焦炭,影响其运输。为减小生焦量,本文提出供氢剂抑焦、供氢催化改质抑焦、超临界流体分散等3种方案,并进行对比分析。研究发现,供氢剂四氢萘只有在加压状态下呈现液相时才能起到供氢作用,其生焦量随着四氢萘加入量的增加而减少。油酸及环烷酸钴具有催化四氢萘的供氢作用,其加入能进一步降低生焦。甲苯在低压状态下对抑制体系生焦不明显,当压力升高到超临界压力后,超临界甲苯由于具有溶解及分散重油的作用,可减少缩合反应,使生焦总量降低。

SEDS工艺制备丝素纳米颗粒及其表征

以丝素蛋白为原料,以六氟异丙醇为溶剂,采用超临界流体强制分散溶液(SEDS)工艺制备了丝素纳米颗粒。单因素实验考察了压力、溶液浓度、溶液流速和CO2流速等因素对丝素纳米颗粒平均粒径分布的影响,并通过Zeta电位、HS-GC、FTIR、XRD和DSC等技术手段对制备的丝素纳米颗粒进行了表征。动态激光光散射仪检测结果表明:随压力、溶液浓度和流速的增大,丝素纳米颗粒平均粒径增大;随CO2流速的增大,丝素纳米颗粒平均粒径减小,最小达到298nm。丝素纳米颗粒Zeta电位为-39mV。HS-GC表明丝素纳米颗粒有机溶剂残留量为20μg/L。FTIR表明经SEDS工艺处理后丝素化学结构和官能团不会发生变化。XRD和DSC显示经SEDS工艺处理后丝素内部分子结构发生重排,由无规则卷曲向β折叠转换。

超临界CO_2抗溶剂法制备紫杉醇缓释微球

采用超临界流体强制分散溶液技术,以D,L-聚乳酸和D,L-聚乳酸-聚乙二醇共聚物为载体材料,分别制备了紫杉醇缓释微球。通过扫描电镜、激光粒度仪检测微球外形及粒径分布;紫外吸光度法测量其载药量和包封率,恒温振荡透析法检测药物的体外释放性能;MTT法检测载药微球对Hela细胞的抑制作用。实验表明,两种载体的缓释微球球形度均较好,表面光滑,平均粒径较小,且粒径分布较窄。以聚乳酸和共聚物为载体的缓释微球载药量分别为5.4%±0.3%和5.3%±0.4%,包封率分别为51%±3%和45%±3%;药物释放呈缓释模式,共聚物载药微球药物释放速率较快。MTT法检测结果表明,载药微球对Hela细胞的增殖有明显抑制,共聚物载药微球对细胞增殖抑制更为明显。

超临界流体强化溶液分散法制备L-聚乳酸微粒

利用超临界流体强化溶液分散法(SEDS法)制备了生物可降解L-聚乳酸(PLLA)微粒,研究不同压力、温度及溶液浓度条件下所制备微粒的大小、形态和分布情况。实验表明:微粒平均粒径为5～26μm,呈球形;微粒粒径和粒径分布随压力的升高而减小,随浓度的增大而增大,温度对微粒粒径的影响不显著。超临界体系中PLLA玻璃化转化温度的降低对微粒影响较大,使微粒粒径变大,粒径分布变宽。高压低温有利于产生粒径小且分布均匀的球形微粒。

SEDS法制备苯甲磺酸妥舒沙星超细微粒的研究

利用超临界流体强制分散溶液(SEDS)技术对甲苯磺酸妥舒沙星进行了超细化研究,考察了四种操作参数即操作压力(8MPa^16MPa)、操作温度(307K^323K)、进样速率(1ml/min^5ml/min)、溶液浓度(6g/L^14g/L)对超细微粒粒度的影响。利用激光粒度仪、扫描电镜(SEM)、X射线粉末衍射(XRD)、差示扫描量热(DSC)等对粒度和形貌进行了表征,分别测定了药物超细处理前后的溶出度。结果表明,利用SEDS法对甲苯磺酸妥舒沙星进行超细化处理后,可以有效改变其溶出速率和溶出程度。

超临界流体强化溶液分散法制备Eudragit S100纳米颗粒

目的：制备Eudragit S100纳米颗粒。方法：采用超临界流体强化溶液分散（SEDS）法制备,考察了Eudragit S100浓度、超临界CO2流速、溶液流速、压力、温度对Eudragit S100纳米粒形貌和粒径的影响,并用场发射扫描式电子显微镜、激光粒度分析仪、差示扫描量热仪、傅里叶变换红外光谱仪对样品进行表征。结果：SEDS法可以制备球形的、粒径分布窄的Eudragit S100纳米粒,所得纳米粒的平均粒径在90~220 nm之间。降低Eudragit S100浓度和温度、升高压力有利于制备形貌好、粒径小的纳米粒;提高超临界CO2流速和降低溶液流速也有利于制备粒径小的纳米粒,但当超临界CO2流速升高至4 kg/h或溶液流速降低至0.5 ml/min时,纳米粒的产率较低。SEDS处理后Eudratit S100仍以无定形态存在,且SEDS过程没有对Eudratit S100的化学键造成破坏。结论：采用SEDS法可用于Eudragit S100纳米粒的制备,工艺简单可行。

压差激活密封剂的制备与应用

为满足油气井密封损伤快速、经济、安全修复的要求,以羧基丁腈胶乳、黄原胶、MgCl2和烷基酚聚氧乙烯醚为原料制备了一种新型压差激活密封剂,通过激光粒度分析仪和超景深三维显微系统分析了密封剂的微观形貌,通过自制的动态堵漏评价设备考察了密封剂的动态堵漏性能,分析了该密封流体的压差激活封堵机理,并在海上G2气田进行了现场应用。结果表明,制备的压差激活密封剂是一种多分散相体系,分散相为复合液滴,胶粒呈规则球状,平均粒径为261.5μm;在15 MPa内可对丝扣、裂缝等不同微泄漏形成良好封堵,封堵性随温度升高而增强。构建的力学-化学耦合新模型表明,复合液滴在漏点压差流场内去水化激活中心粒子,活性粒子聚结填充泄漏孔隙,实现自适应封堵。该压差激活密封剂在海上环空带压井进行了泄漏修复应用,效果良好。图10参28。

Dust dispersion and management in underground mining faces

Presence of fine dust in air causes serious health hazard for mine operators resulting in such serious problems as coal workers’pneumoconiosis and silicosis.Major sources of dust appear of course along the mining face where the minerals are extracted.Proper control and management are required to ensure safe working environment in the mine.Here,we utilize the computational fluid dynamic(CFD)approach to evaluate various methods used for mitigating dust dispersion from the mining face and for ensuring safe level of dust concentration in the mine tunnel for safety of the operators.The methods used include:application of blowing and exhaust fans,application of brattice and combination of both.The results suggest that among the examined methods,implementation of appropriately located brattice to direct the flow from the main shaft to the mining face is the most effective method to direct dust particles away from the mining face.

Horizontal gas mixing in rectangular fluidized bed:A novel method for gas dispersion coefficients in various conditions and distributor designs

In a rectangular fluidized bed combustor, the tracer gas is injected continuously into the bed from a point source at the center of the distributor plate. In this study, a general governing equation is formulated for tracer gas dispersion in the bed. An analytical solution is derived to estimate the dispersion coefficients, Dxand Dy, in a horizontal plane. The concentration profiles at different sampling heights with various gas velocities are plotted.Subsequently, to estimate the dispersion coefficients, surface fitting of the obtained analytical solution to the experimental data is performed. The dispersion coefficients obtained from this model are compared with those of a conventional model. Additionally, the effect of walls, bed height and gas injection rate on the dispersion coefficients in a horizontal plane is investigated, and the effect of distributor design on the dispersion coefficients in a horizontal plane is investigated with different tracer positions. It is found that Dxand Dyare nearly equivalent at a lower tracer gas ratio of the injected gas to the total gas flow rate. It is also demonstrated that the effect of bed height on Dxis minor. This model is also able to estimate the dispersion coefficients in the case of a multihorizontal nozzle distributor.

Effects of reinforced nanofluid with nanoparticles on cutting tool wear morphology

Superalloys are grouped as hard-to-cut materials with relatively poor machinability.Tool wear is considered one of the main machinability attributes in machining superalloys.Although numerous works have been reported on factors governing tool life in machining superalloys,no study was found on the effect of nanoparticles stability on nanofluid performance and consequently resulted tool wear morphologies.In the present work,the nanoparticles were reinforced by means of improving the stability of the base fluid.To that accomplished,the surface active agent (surfactant) was added to the base cutting fluid as a reinforcing element.The effects of new lubricant on the tool wear morphology of A286 works parts were assessed.

CFD modelling and optimization of oxygen supply mode in KIVCET smelting process

The influence of oxygen supply mode on the KIVCET (a Russian acronym for flash?cyclone?oxygen?electric?smelting) process was investigated using numerical simulation. The mass rate ratio (MRR) of central oxygen to lateral oxygen of the central jet distributor (CJD) burner was defined to express the oxygen supply mode, and the KIVCET process with an MRR ranging from 0.09 to 0.39 was simulated. The results show that there are four efficient reaction regions that correspond to four CJD burners. A higher central oxygen flow improves the mixing between particles and oxygen, thus enhancing reactions and shortening the reaction regions. However, a higher dust rate is induced due to the spread of the particle columns. The optimal MRR for a KIVCET furnace with a smelting capacity of 50000 kg/h is suggested to be 0.31. In this case, the chemical reactions associated with the feed are completed with an acceptable dust rate.

The Resident Time Distribution of Injected Dispersed Drops in Stirred Extraction Columns

A resident time model is proposed to evaluate the performance of agitated extraction columns. In this model, the resident time of dispersed drops is simulated with the discrete phase modeling, where the continuous phase and the dispersed phase （drops） are described by the single-phase Navier-Stokes （turbulence） model and Lagrangian model, respectively. The interaction of dispersed phase and continuous phase is neglected for the low concentration of drop in the cases studied. The statistical parameters of drops （the average resident time and standard deviation） under different operation conditions are computed for four columns. The relation of the above statistical parameters with the performance of columns is discussed and the criterions for an optimal compartment are outlined. Our results indicate that the resident time model is useful to evaluate the performance and optimize the design of extraction columns.

Modeling the influence of forced ventilation on the dispersion of droplets ejected from roadheader-mounted external sprayer

In order to reveal the influence of forced ventilation on the dispersion of droplets ejected from roadheader-mounted external sprayer,the paper studies the air-flowing field and the droplet distribution under the condition of gentle breeze and normal forced ventilation in heading face using the particle tracking technology of computational fluid dynamics(CFD).The results show that air-flowing tendency in the same section presents great comparability in the period of gentle breeze and forced ventilation,and the difference mainly embodies in the different wind velocity.The influence of ventilation on the dispersion of droplets is faint under the gentle breeze condition.The droplet can be evenly distributed around the cutting head.However,under the normal forced ventilation,a large number of droplets will drift to the return air side.At the same time,droplet clusters are predominantly presented in the lower part of windward side and the middle of the leeward side around the cutting head.In contrast,the droplet concentration in other parts around cutting head decreases a lot and the droplets are unable to form close-grained mist curtain.So the dust escape channel is formed.In addition,the simulation results also reveal that the disturbance of air flow on the droplet distribution can be effectively relieved when using ventilation duct with Coanda effect(VDCE).Field experiment results show that the dust suppression efficiency of total dust and respirable dust increases respectively by 10.5%and 9.3%when using VDCE,which proves that it can weaken the influence of airflow on droplet dispersion.