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相变材料的过冷现象及其抑制方法的研究进展 被引量:21
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作者 张正飞 秦紫依 +1 位作者 李勇 王毅 《材料导报》 EI CAS CSCD 北大核心 2019年第21期3613-3619,共7页
过冷是材料液-固相变过程中为提供离子扩散、晶体生长及晶面扩大所需能量而产生的一种亚稳态。过冷是结晶过程的推动力,但大的过冷度导致相变材料结晶温度降低、结晶时间延迟,使得储存的潜热不能及时释放,储-放热温度不匹配,降低了热能... 过冷是材料液-固相变过程中为提供离子扩散、晶体生长及晶面扩大所需能量而产生的一种亚稳态。过冷是结晶过程的推动力,但大的过冷度导致相变材料结晶温度降低、结晶时间延迟,使得储存的潜热不能及时释放,储-放热温度不匹配,降低了热能利用效率。过冷度大已成为限制相变储热技术规模化应用的重要影响因素之一。大量实验结果表明:过冷现象与熔体晶核的生成与长大速率、环境温度、接触面的粗糙程度、熔体温度等因素有关,但其产生的内在机制尚不明确,影响规律和调控手段仍需借助实验探索。目前,主要采用外加添加剂或在胶囊化、流体化过程中加入添加剂的添加晶种法,以及通过搅拌、超声振荡和鼓泡等外部刺激的动力学成核法诱发过冷液体结晶。利用外加成核剂、纳米颗粒以及部分未熔化母相晶体作为晶核诱发非均匀成核是抑制过冷现象最常用、最有效的方法。为提高添加剂的分散性和抑制水合无机盐类相变材料的相分离现象,在添加成核剂的同时往往需要加入一定量的增稠剂,但成核剂和增稠剂的添加量需要优化。胶囊化可以改变相变材料的结晶特性,目前的研究一致认为在胶囊化前添加成核剂有利于改善相变材料的过冷度。动力学成核常采用的方法是超声振荡法,其通过空化作用使晶体持续破碎并与熔体混合而提高晶核的分散性和加速结晶过程。在超声的同时添加纳米颗粒也有利于抑制过冷度。本文简述了过冷现象和典型的过冷曲线,分析了影响过冷度的因素,并着重介绍了外加添加剂法、胶囊化法、功能流体法和超声振荡法等抑制过冷度的方法。 展开更多
关键词 相变材料 过冷度 成核理论 过冷度抑制 胶囊化法 功能流体 添加剂 超声振荡
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微胶囊在食品开发中的应用
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作者 周秀琴 《食品研究与开发》 CAS 1989年第4期16-18,共3页
当今食品加工技术中出现一种先进的微胶囊技术,美国约60%的饮料生产使用这种技术。微胶囊技术具体说来就是利用可形成胶囊壁或膜的物质,将核心物质包覆、固化、脱水,使之与环境中温度、水等隔绝,达到保护核心物质的作用,延长食品的保藏... 当今食品加工技术中出现一种先进的微胶囊技术,美国约60%的饮料生产使用这种技术。微胶囊技术具体说来就是利用可形成胶囊壁或膜的物质,将核心物质包覆、固化、脱水,使之与环境中温度、水等隔绝,达到保护核心物质的作用,延长食品的保藏和使用期。核心物质可以是固体、液体或气体,大小在0.1~4000微米之间,常用的胶囊壁形成物质有水溶性胶类、淀粉、纤维素衍生物、动物胶、酪蛋白等,可单独或多种合并使用。本文就胶囊化法的应用与微胶囊技术在食品中的其它应用介绍如下: 展开更多
关键词 食品工艺 胶囊技术 胶囊化法
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Capsule endoscopy in neoplastic diseases 被引量:17
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作者 Marco Pennazio Emanuele Rondonotti Roberto de Franchis 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第34期5245-5253,共9页
Until recently, diagnosis and management of small-bowel tumors were delayed by the diffi culty of access to the small bowel and the poor diagnostic capabilities of the available diagnostic techniques. An array of new ... Until recently, diagnosis and management of small-bowel tumors were delayed by the diffi culty of access to the small bowel and the poor diagnostic capabilities of the available diagnostic techniques. An array of new methods has recently been developed, increasing the possibility of detecting these tumors at an earlier stage. Capsule endoscopy (CE) appears to be an ideal tool to recognize the presence of neoplastic lesions along this organ, since it is non-invasive and enables the entire small bowel to be visualized. High- quality images of the small-bowel mucosa may be captured and small and ? at lesions recognized, without exposure to radiation. Recent studies on a large population of patients undergoing CE have reported small-bowel tumor frequency only slightly above that reported in previous surgical series (range, 1.6%-2.4%) and have also confirmed that the main clinical indication to CE in patients with small-bowel tumors is obscure gastrointestinal (GI) bleeding. The majority of tumors identified by CE are malignant; many were unsuspected and not found by other methods. However, it remains difficult to identify pathology and tumor type based on the lesion’s endoscopic appearance. Despite its limitations, CE provides crucial information leading in most cases to changes in subsequent patient management. Whether the use of CE in combination with other new diagnostic (MRI or multidetector CT enterography) and therapeutic (Push- and-pull enteroscopy) techniques will lead to earlier diagnosis and treatment of these neoplasms, ultimately resulting in a survival advantage and in cost savings,remains to be determined through carefully-designed studies. 展开更多
关键词 Capsule endoscopy ENTEROSCOPY Obscure gastrointestinal bleeding Small-bowel tumors Polyposis syndromes
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Colon capsule endoscopy 被引量:4
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作者 Ignacio Fernandez-Urien Cristina Carretero +1 位作者 Ana Borda Miguel Muoz-Navas 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第34期5265-5268,共4页
Wireless capsule endoscopy has become the first imaging tool for small bowel examination. Recently, new capsule endoscopy applications have been developed, such as esophageal capsule endoscopy and colon capsule endosc... Wireless capsule endoscopy has become the first imaging tool for small bowel examination. Recently, new capsule endoscopy applications have been developed, such as esophageal capsule endoscopy and colon capsule endoscopy. Clinical trials results have shown that colon capsule endoscopy is feasible, accurate and safe in patients suffering from colonic diseases. It could be a good alternative in patients refusing conventional colonoscopy or when it is contraindicated. Upcoming studies are needed to demonstrate its utility for colon cancer screening and other indications such us ulcerative colitis. Comparative studies including both conventional and virtual colonoscopy are also required. 展开更多
关键词 Capsule endoscopy COLON POLYP Colon cancer SCREENING COLONOSCOPY
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Patency and agile capsules 被引量:5
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作者 ngel Caunedo-lvarez Javier Romero-Vazquez Juan M Herrerias-Gutierrez 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第34期5269-5273,共5页
Small bowel strictures can be missed by current diagnostic methods. The Patency capsule is a new non-endoscopic dissolvable capsule which has as an objective of checking the patency of digestive tract, in a non-invasi... Small bowel strictures can be missed by current diagnostic methods. The Patency capsule is a new non-endoscopic dissolvable capsule which has as an objective of checking the patency of digestive tract, in a non-invasive manner. The available clinical trials have demonstrated that the Patency capsule is a good tool for assessment of the functional patency of the small bowel, and it allows identification of those patients who can safely undergo a capsule endoscopy, despite clinical and radiographic evidence of small-bowel obstruction. Some cases of intestinal occlusion have been reported with the Patency capsule, four of them needed surgery. So, a new capsule with two timer plugs (Agile capsule) has been recently developed in order to minimize the risk of occlusion. This new device stars its dissolution process earlier (30 h after ingestion) and its two timer plugs have been designed to begin the disintegration even when the device is blocked in a tight stricture. 展开更多
关键词 Capsule endoscopy Patency capsule Agile capsule Small bowel strictures
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Capsule endoscopy in non-steroidal anti-inflammatory drugs-enteropathy and miscellaneous,rare intestinal diseases 被引量:9
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作者 Gerard Gay Michel Delvaux Muriel Frederic 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第34期5237-5244,共8页
Despite significant advances over the last decade, mucosal lesions of the small bowel are poorly detected by imaging studies such as CT scan, MRI-enteroclysis and contrast-enhanced abdominal ultrasound. Capsule endosc... Despite significant advances over the last decade, mucosal lesions of the small bowel are poorly detected by imaging studies such as CT scan, MRI-enteroclysis and contrast-enhanced abdominal ultrasound. Capsule endoscopy (CE) has dramatically changed the diagnostic approach to intestinal diseases. Moreover, the use of CE can be extended to include other conditions. However, it is diffi cult to assess the positive influence of CE on patient outcomes in conditions involving a small number of patients, or in critically ill and diff icult to examine patients. CE has the advantage of diagnosing intestinal lesions and of directing the use of double balloon enteroscopy (DBE) in order to obtain biopsy specimens. Moreover, CE allows repeated assessment in chronic conditions, especially to detect relapse of an infectious disease. 展开更多
关键词 Capsule endoscopy Non-steroidal anti-inflammatory drugs-enteropathy Intestinal diseases
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Esophageal capsule endoscopy 被引量:4
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作者 Ignacio Fernandez-Urien Cristina Carretero +1 位作者 Raul Armendariz Miguel Muoz-Navas 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第34期5254-5260,共7页
Capsule endoscopy is now considered as the first imaging tool for small bowel examination. Recently, new capsule endoscopy applications have been developed, such as esophageal capsule endoscopy and colon capsule endos... Capsule endoscopy is now considered as the first imaging tool for small bowel examination. Recently, new capsule endoscopy applications have been developed, such as esophageal capsule endoscopy and colon capsule endoscopy. Esophageal capsule endoscopy in patients with suspected esophageal disorders is feasible and safe, and could be also an alternative procedure in those patients refusing upper endoscopy. Although large-scale studies are needed to confirm its utility in GERD and cirrhotic patients, current results are encouraging and open a new era in esophageal examination. 展开更多
关键词 Capsule endoscopy ESOPHAGUS Gastroe-sophageal reflux disease VARICES ESOPHAGOSCOPY PillCam ESO
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Study on Microcapsulation of Onion Oil with Complex Coacervation and Spray Drying Method 被引量:1
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作者 LIU Nan-nan 《Chinese Food Science》 2012年第4期4-6,8,共4页
[Objective] The aim was to study the microcapsulation of onion oil with double place separation-coacevation and spray drying. [Method] The effect of processing parameters which included the different wall material com... [Objective] The aim was to study the microcapsulation of onion oil with double place separation-coacevation and spray drying. [Method] The effect of processing parameters which included the different wall material combination,the ratio between the wall material,the core material content and the feed concentration on the efficiency and yield of microencapsulated was evaluated by single factor experiments. [Result] Through orthogonal optimization experiments, the optimum condition was as follows: the ratio of Arabic gum and maltodextrin ration was 1∶1, the core content was 25%, feed composition was 18%, and the microencapsulation efficiency and yield can reach 80.7% and 95.3% respectively. [Conclusion] The microcapsulaiton of onion oil with complex coacervation spray drying method can increase membrane thickness, improve core stability and prolong shelf life of products. 展开更多
关键词 Spray drying Onion oil flavor MICROENCAPSULATION China
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Microencapsulation of immunoglobulin Y: optimization with response surface morphology and controlled release during simulated gastrointestinal digestion 被引量:3
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作者 Jin ZHANG Huan-huan LI +7 位作者 Yi-fan CHEN Li-hong CHEN Hong-gang TANG Fan-bin KONG Yun-xin YAO Xu-ming LIU Qian LAN Xiao-fan YU 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2020年第8期611-627,共17页
Immunoglobulin Y(Ig Y)is an effective orally administered antibody used to protect against various intestinal pathogens,but which cannot tolerate the acidic gastric environment.In this study,Ig Y was microencapsulated... Immunoglobulin Y(Ig Y)is an effective orally administered antibody used to protect against various intestinal pathogens,but which cannot tolerate the acidic gastric environment.In this study,Ig Y was microencapsulated by alginate(ALG)and coated with chitooligosaccharide(COS).A response surface methodology was used to optimize the formulation,and a simulated gastrointestinal(GI)digestion(SGID)system to evaluate the controlled release of microencapsulated Ig Y.The microcapsule formulation was optimized as an ALG concentration of 1.56%(15.6 g/L),COS level of 0.61%(6.1 g/L),and Ig Y/ALG ratio of 62.44%(mass ratio).The microcapsules prepared following this formulation had an encapsulation efficiency of 65.19%,a loading capacity of 33.75%,and an average particle size of 588.75μm.Under this optimum formulation,the coating of COS provided a less porous and more continuous microstructure by filling the cracks on the surface,and thus the GI release rate of encapsulated Ig Y was significantly reduced.The release of encapsulated Ig Y during simulated gastric and intestinal digestion well fitted the zero-order and first-order kinetics functions,respectively.The microcapsule also allowed the Ig Y to retain 84.37%immune-activity after 4 h simulated GI digestion,significantly higher than that for unprotected Ig Y(5.33%).This approach could provide an efficient way to preserve Ig Y and improve its performance in the GI tract. 展开更多
关键词 Immunoglobulin Y(IgY) MICROENCAPSULATION Chitooligosaccharide(COS) Response surface methodology(RSM) Controlled release Simulated gastrointestinal digestion(SGID)
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