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21.
A capsule system driven by a harmonic force applied to its inner mass is considered in this study. Four various friction models are employed to describe motion of the capsule in different environments taking into account Coulomb friction, viscous damping, Stribeck effect, pre-sliding, and frictional memory. The non-linear dynamics analysis has been conducted to identify the optimal amplitude and frequency of the applied force in order to achieve the motion in the required direction and to maximize its speed. In addition, a position feedback control method suitable for dealing with chaos control and coexisting attractors is applied for enhancing the desirable forward and backward capsule motion. The evolution of basins of attraction under control gain variation is presented and it is shown that the basin of the desired attractors could be significantly enlarged by slight adjustment of the control gain improving the probability of reaching such an attractor. 相似文献
22.
《Arabian Journal of Chemistry》2022,15(11):104239
Today, the principle of research and development is pulmonary drug delivery due to the potential for maximizing therapeutic effects for patients by direct drug targeting the pathology site in the lungs. Amongst the convenient delivery alternatives, the Dry Powder Inhaler (DPI) is the preferred device to remedy a variety of diseases. In this regard, the fabrication and development of a novel formulation for DPI capsules have been studied. We investigated the effects of various parameters, such as percentages of polyethylene glycol (PEG), propylene glycol (PG), glycerol (Gly), brittleness, test conditions, and particle release of manufactured DPI capsules. The efficacy of each parameter was evaluated in detail to understand and address the consequences of the mentioned factors. The results illustrated that the lower molecular weight of PEGs presented the better plasticizing capability of gelatin. Owing to the hygroscopicity of the utilized plasticizer, polyethylene glycol 400 (PEG 400) increased the capsule flexibility for a longer time and its stability under environmental conditions in the gelatin capsule formulation. Likewise, no particle release was observed in the gelatin/PEG capsule. The prepared gelatin/PEG400 capsules were compared with pure gelatin and HPMC capsules. The capsules were evaluated in terms of loss on drying (LOD), surface morphology, roughness, and puncture type. The results show that using PEG-400 can lead to the production of capsules that have low moisture content and minimal interaction with APIs. In addition, gelatin/PEG capsules have no particles due to the smooth surface after the punching process. The as-produced capsules are not blocked again after punching, allowing the patient to take the drug completely. In fact, the present research provided substantial insight regarding the development of DPI formulation in capsule investigations on an industrial scale. 相似文献
23.
共缩聚聚酰胺胶囊的制备及其性质的研究 总被引:7,自引:1,他引:7
界面缩聚法是制备微胶囊的常用办法之一,在医药、农药、生物工程等各个领域得到了广泛的研究与应用.此法制备聚酰胺胶囊具有制备方法简单、缩聚速度快、囊壁孔隙大等优点.在制备胶囊时,一般以一种二元胺或多元胺作为水溶性单体,制备的微胶囊存在很大的缺陷.当用二元胺作为水溶性单体时,得到具有线型结构的聚酰胺胶囊,囊壁的机械强度差.采用多元胺作为水溶性单体时,反应深度小,制备的胶囊囊壁薄、孔隙小.我们采用二元胺和多元胺的混合物作为水溶性单体,得到了不规则缩聚的共缩聚胶囊.改变二元胺与多元胺的比例,改善囊壁的机械强度和对KCl 的渗透系数,从而制备出具有较高机械强度和较大渗透系数的胶囊,以适应实际应用中对芯材控制释放的要求. 相似文献
24.
An experimental investigation of cold storage in an encapsulated thermal storage tank 总被引:5,自引:0,他引:5
Sih-Li Chen Chin-Lung Chen Chun-Chuh Tin Tzong-Shing Lee Ming-Chun Ke 《Experimental Thermal and Fluid Science》2000,23(3-4):133-144
This paper experimentally investigates the thermal performance and the pressure drop of an encapsulated thermal storage tank during the charging process. A polyvinyl chloride (PVC) hollow cylinder is used as the thermal storage tank. The cylindrical capsules inside the thermal storage tank utilize water added with nucleation agents as the phase change material (PCM), and the coolant is the aqueous solution of ethylene glycol. A series of experiments were carried out to investigate the effects of the inlet coolant temperature and coolant flow rate on nucleation of capsules, heat transfer and pressure drop of the tank. The results indicate that cool energy can be fully stored in the form of latent heat when the inlet coolant temperature is set below the temperature with 100% nucleation probability. The lower the inlet coolant temperature and the larger the coolant flow rate, the more efficient the storage tank. A correlation for the pressure drop of coolant during a charging process is also developed. 相似文献
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26.
A simple, sensitive, and accurate liquid-chromatographic method with UV detection has been developed for simultaneous determination
of spinosin, danshensu, and protocatechuic aldehyde in traditional Chinese Zaoren-an-shen capsules. Chromatographic separation
was achieved on a C18 column. Vanillin was used as internal standard and the UV detection wavelength was 280 nm. Excellent linear behavior was
observed over the concentration ranges investigated, with R values higher than 0.9997 for all the analytes. The limits of quantification for spinosin, danshensu, and protocatechuic
aldehyde were 1.31, 0.74, and 0.27 μg mL−1, respectively. This validated method can be used for routine quality control of Zaoren-an-shen capsules. 相似文献
27.
Eyewear-style three-dimensinal endoscope derived from microstructured polymer fiber with function of image transmission 下载免费PDF全文
A method of fabricating multi-core polymer image fiber is proposed. Image fiber preform is fabricated by stacking thousands of polymer fibers each with a 0.25-mm diameter orderly in a die by only one step. The preform is heated and stretched into image fiber with an outer diameter of 2 mm. Then a portable eyewear-style three-dimensional (3D) endoscope system is designed, fabricated, and characterized. This endoscopic system is composed of two graded index lenses, two pieces of 0.35-m length image guide fibers, and a pair of oculars. It shows good flexibility and portability, and can provide the depth information accordingly. 相似文献
28.
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30.
内窥镜的红外激光传输用柔性空芯光纤的研制 总被引:1,自引:3,他引:1
通过理论计算确立了多功能介质-金属结构空芯光纤的结构参量,优化了液相镀膜法的有关条件,明确了具体制作参量。制作了以聚碳酸酯毛细管为基管的,高柔韧性的,可同时低损耗传输红外目标波长激光和可见导航光红外的空芯光纤。对光纤传输性能进行了测试。在2.94μm波长的Er∶YAG和0.63μm波长的红色半导体激光器的直线损耗分别为0.4 dB/m和3 dB/m。组装在医疗内窥镜中的柔性空芯光纤,在先端以0.9 cm半径135°角弯曲时,对Er∶YAG激光仍有近70%的传输效率;绿色导航光在内窥镜中的的损耗值为11 dB,绿色指示点在内窥镜的视窗中清晰可见。结果表明此种光纤在内窥镜的激光传输方面有重要的应用价值。 相似文献