2014年7月22日 · Chronic venous insufficiency (CVI) describes a condition that affects the venous system of the lower extremities, with the sine qua non being persistent ambulatory venous hypertension causing various pathologies, including pain, edema, skin changes, and ulcerations. CVI often indicates the more advanced forms of venous disorders, including ...

2022年7月17日 · Chronic venous insufficiency slows down blood flow from your legs back up to your heart. Without treatment, CVI raises the pressure in your leg veins so much that your tiniest blood vessels (capillaries) burst. When this happens, the skin in that area takes on a reddish-brown color and can easily break open if bumped or scratched.

2024年12月18日 · Chronic venous insufficiency manifests as a spectrum of signs and symptoms, including varicose veins, leg swelling, skin changes, and leg ulcers. The condition is caused...

Chronic venous insufficiency (CVI) is a condition in which the flow of superficial or deep venous blood is impaired, causing venous hypertension. CVI encompasses several pathological changes (eg, lower extremity edema, skin trophic changes, and discomfort) that result secondary to venous hypertension.[1][2] Chronic venous insufficiency is a ...

2024年12月19日 · Nonsurgical management of CVI includes reducing central venous hypertension, compression therapy, leg elevation, and exercises involving the calf and foot flexion/extension that provide a pump-function effect.

2000年11月14日 · CVI is characterized by symptoms or signs produced by venous hypertension as a result of structural or functional abnormalities of veins. The most frequent causes of CVI are primary abnormalities of the venous wall and the valves and secondary changes due to previous venous thrombosis that can lead to reflux, obstruction, or both.

2021年10月21日 · Chronic venous insufficiency is highly prevalent in the population and is associated with the presence of cardiovascular risk factors and disease. Individuals with CVI experience an elevated risk of death, which is independent of age and sex, and present cardiovascular risk factors and comorbidities …

2021年8月13日 · The major findings of this study are that (i) CVI has a high prevalence in the population, (ii) cardiovascular disease and CVI are interdependent and share risk factors, and (iii) CVI represents a strong predictor for all-cause mortality in the general population beyond established risk factors (Graphical abstract). The association with all ...

2025年1月3日 · Chronic Venous Insufficiency (CVI) is a progressive and multifaceted vascular disorder characterized by venous hypertension, valvular incompetence, and chronic inflammation. These pathophysiological mechanisms contribute to a spectrum of clinical manifestations, from asymptomatic varicose veins to severe complications such as venous ulcers.

Chronic venous insufficiency (CVI) is a potentially debilitating disorder associated with serious complications such as lower extremity venous ulcers. This article reviews the incidence and pathophysiology of CVI, nursing assessment, diagnosis and interventions, and patient education needed to manag …

2020年6月21日 · 聚类有效性指标（Cluster Validity Index，CVI）用于度量聚类的效果。很显然，希望彼此相似的样本在一个簇，彼此不相似的样本尽量在不同的簇。也就是说：同一簇的样本彼此之间相似，不同簇之间的样本尽可能不同。

2024年10月25日 · Chronic venous insufficiency occurs due to inadequate functioning of venous walls and/or valves in the lower limbs resulting in excessive pooling of blood. Symptoms of chronic venous insufficiency include heaviness, tension, …

量表内容效度的定量评价中应用最广泛的指标是内容效度指数。内容效度指数分为条目水平的内容效度指数(i-cvi)和量表水平的内容效度指数(s-cvi)两类。结...展开更多

脉络膜血管指数（cvi ）是脉络膜图像处理后所得脉络膜血管腔面积（la）与脉络膜总面积（tca）的比值，既可以反映出脉络膜内血管成分的改变，又可作为后续治疗效果的观察指标。

化学气相渗透工艺（technology of chemical vapor infiltration）是指将一种或几种烃类气体化合物经高温分解、缩聚之后炭沉积在多孔介质内部，使材料致密化的方法，是新发展起来的制备无机材料新技术，也称 化学气相沉积。 该技术主要用于制备各种高温 陶瓷基复合材料，包括炭-炭复合材料和以碳化物、氮化物为基质的材料，此外，还可以制备各种不透气的元件。 化学气相渗透工艺（technology of chemical vapor infiltration）是指将一种或几种烃类气体化合物经高温分解、缩 …

化学气相沉积（Chemical Vapor Deposition, CVD）和化学气相渗透（Chemical Vapor Infiltration, CVI）是两种广泛应用于材料制造与表面处理的化学气相技术。 尽管它们在原理和应用上有一定的相似性，但在具体的工艺…

化学气相渗透工艺（technology of chemical vapor infiltration）是指将一种或几种烃类气体化合物经高温分解、缩聚之后炭沉积在多孔介质内部，使材料致密化的方法，是新发展起来的制备无机材料新技术，也称 化学气相沉积。 该技术主要用于制备各种高温 陶瓷基复合材料，包括炭-炭复合材料和以碳化物、氮化物为基质的材料，此外，还可以制备各种不透气的元件。 CVI法是化学气相沉积 (CVD)法的一种延伸。 1962年，Bickerdike首次提出利用CVI法增加多孔碳材料的密度。 …

2024年10月15日 · 化学气相沉积（Chemical Vapor Deposition, CVD）和化学气相渗透（Chemical Vapor Infiltration, CVI）是两种广泛应用于材料制造与表面处理的化学气相技术。 尽管它们在原理和应用上有一定的相似性，但在具体的工艺操作、材料选择以及最终产品的性能方面，它们各自有着显著的差别。 CVD 是一种利用化学反应在基材表面沉积薄膜的技术。 通过将反应气体引入反应室，气体与加热后的基材表面发生化学反应，从而生成固态物质，这些固态物质逐渐沉积在基 …

2D SiC f /SiC composites with excellent mechanical properties were successfully prepared by hybrid chemical vapor infiltration (CVI) and precursor infiltration and pyrolysis (PIP) processes, which consisted of depositing a protective layer of CVI-SiC on the fiber preform with BN interphase, followed by cyclic precursor infiltration and ...

摘要 综述了化学气相沉积（CVD）技术的最新发展，包括金属有机化合物化学气相沉积、等离子辅助化学气相沉积、激光化学气相沉积；同时介绍了三种用于制备工程材料的快速致密化化学气相渗透（CVI）技术，包括强迫流动热梯度化学气相渗透、...