Middle range wireless power transfer systems with multiple resonators

The equivalent two-port network model of a middle range wireless power transfer(WPT) system was presented based on strongly coupled multiple resonators. The key parameters of the WPT system include self-inductance, resistance, parasitic capacitance, mutual inductance and S-parameters of coils & resonators were analyzed. The impedance matching method was used to optimize load power and transmission efficiency of the multi-resonator WPT system, and the impedance matching method was realized through adjusting the distances between the coils and resonators. Experiments show that the impedance matching method can effectively improve load power and transmission efficiency for middle range wireless power transfer systems with multiple resonators, at distances up to 3 times the coil radius with efficiency more than 70% and load power also close to 3.5 W.

Building Knowledge: The Concept of Care

Aim and Objectives: The aim of this article is to explore whether the specific levels of caring described in Swanson’s Middle Range Caring Theory which include characteristics of caring, people’s concerns and commitments underlying caring, conditions that enhance/inhibit caring and consequences of caring and non-caring could be used in categorizing findings from two literature reviews investigating the concept of care. Background: Nursing has a long legacy as a caring/healing profession where caring is increasingly posited as one of the core concepts in modern nursing science. However, the meanings given to the concept of care remain elusive, ambiguous and unclear. Design: Two systematic literature reviews. Method: Twenty-nine articles based on strategic inclusion and exclusion criteria were synthesized. Data was retrieved from CINAHL, Medline, Embase and PsycInfo covering the period 2003-2016. The literature search used the key words care, concept analysis, systematic review, meta-synthesis, meta-analysis and narrative review. Results: Major themes found were related to the following characteristics of caring persons: compassionate, knowledgeable, positive and reflective. Concerns and commitments underlying caring were doing the right thing, connecting, focusing on the others’ experience, acknowledging individual dignity and worth and being present. Conditions that enhanced/inhibited caring were situational constraints, personality traits, communication skills, health problems and organizational features. Consequences of caring and non-caring actions included both positive and negative emotional, spiritual, physical, and social outcomes for patients, families and nurses. Conclusion: The specific levels of caring described in Swanson’s Middle Range Caring Theory are highly suitable for categorizing the findings from three literature reviews on the concept of care. Relevance to Clinical Practice: Swanson’s Middle Range Caring Theory can be used to guide clinical practice and encourage an individual approach to care. It has been shown to contain clear, comprehensible language in its theoretical basis;this encourages use in clinical practice.