In condensed matter physics, materials with kagome lattice display a range of exotic quantum states, including charge density wave (CDW), superconductivity and magnetism. Recently, the intermetallic kagome metal ScV6Sn6 was discovered to undergo a first-order structural phase transition with the formation of a root3xroot3x3 CDW at around 92 K. The bulk electronic band properties are crucial to understanding the origin of the structural phase transition. Here, we conducted an optical spectroscopy study in combination with band structure calculations across the structural transition. Our findings showed abrupt changes in the optical reflectivity/conductivity spectra as a result of the structural transition, without any observable gap formation behavior. The optical measurements and band calculations actually reveal a sudden change of the band structure after transition. It is important to note that this phase transition is of the first-order type, which distinguishes it from conventional density-wave type condensations. Our results provide an insight into the origin of the structural phase transition in this new and unique kagome lattice.
This research proposes to construct a new teaching mode for oral business English based on production-oriented approach. The author first explores the theory and principles of POA, and then construct and implement the POA teaching mode for oral business English teaching through a real example of teaching practice.
Characteristics of deep-sea manganese nodule and principle of its metallurgical treatment were briefly introduced.Process,operating conditions,metal recovery and respective merits and demerits for processing techniques of deep-sea manganese at present in and out of China were reviewed.The exploring processes of using BR as a novel reductant and 3-phases oxidation method were introduced.A new idea was proposed for processing manganese nodules into Mn-Fe alloys or valuable metals by FFC Cambridge process.Applications of Mn-Fe alloys was also introduced.
In this paper,an intrusion detection method based on fuzzy genetics is presented.This method can compete mastered knowledge inheriting by selection operation to former rules,can perform rules mutation operation by resemble degree computation.This method can effectively control rule number and accelerate intrusion detection process with SRPP fitness function,also can produce new rules with mutation.Experimental results demonstrate the proposed method can accelerate the intrusion process,relieve detection load,improve detection rate,decrease false positive and false negative rate.
The topological Weyl semimetals with peculiar band structure exhibit novel nonlinear optical enhancement phenomena even for light at optical wavelengths. While many intriguing nonlinear optical effects were constantly uncovered in type-I semimetals, few experimental works focused on basic nonlinear optical properties in type-II Weyl semimetals. Here we perform a fundamental static and time-resolved second harmonic generation (SHG) on the three dimensional Type-II Weyl semimetal candidate $β$-WP$_2$. Although $β$-WP$_2$ exhibits extremely high conductivity and an extraordinarily large mean free path, the second harmonic generation is unscreened by conduction electrons, we observed rather strong SHG response compared to non-topological polar metals and archetypal ferroelectric insulators. Additionally, our time-resolved SHG experiment traces ultrafast symmetry switching and reveals that polar metal $β$-WP$_2$ tends to form inversion symmetric metastable state after photo-excitation. Intense femtosecond laser pulse could optically drive symmetry switching and tune nonlinear optical response on ultrafast timescales although the interlayer coupling of $β$-WP$_2$ is very strong. Our work is illuminating for the polar metal nonlinear optics and potential ultrafast topological optoelectronic applications.
Increasing penetration of renewables require ade-quate flexible resources to handle significant uncertainty. The current capacity market lacks a clearing mechanism for the flexibility capacity, and causes consumers to bear extra cost on additional flexible resources. Designing a fair and reason-able clearing and repayment mechanism for flexible resources is challenging, especially for newly market participants with complicated temporarily and dynamics, such as energy storage. This paper designs a novel capacity market model that involves demands of flexible ramping resource. Firstly, a ramp resource constraint is established based on historical data of wind and solar generations. Then, a reasonable clearing mechanism is designed to promote the investment and construction of energy storage. Case studies on realistic power systems verified that the proposed model guarantees the benefit of flexible units, and enables adequate ramp capabilities.
Ethical competency is important to head nurses' transformational leadership, however, few researches have explored their correlation, Additionally, most studies used variable-oriented approach to examine ethical competence, without considering it as a multidimensional concept. This study aimed to identify the latent profiles of head nurses' ethical competence and examine differences in transformational leadership across latent profiles. Convenience sampling was used to recruit 329 head nurses from four tertiary hospitals in Changsha, Hunan province, China. This study collected data by using social-demographic survey, Ethical Competence Questionnaire, and Head Nurse's Transformational Leadership Self-rating Scale between July and August 2023. Latent profile analysis (LPA) was employed to identify latent profiles of ethical competency. One-way ANOVA test and the Kruskal–Wallis test were used to compare the transformational leadership scores across latent profiles of ethical competency. The mean scores of ethical competence and transformational leadership were 4.045 ± 0.394 and 4.555 ± 0.419, respectively. This study identified three latent profiles of head nurses' ethical competence, and those profiles labelled "low ethical competence" (n = 60, 18.2%), "moderate ethical competence" (n = 217, 66.0%) and "high ethical competence" (n = 52, 15.8%). The average score of transformational leadership was also statistically different (F = 26.446, p = 0.000) across the three profiles. Our findings underscore the importance of tailoring interventions to address the varying profiles of ethical competence among head nurses. Enhancing ethical competence can strengthen transformational leadership, ultimately leading to improved patient outcomes and overall healthcare quality.
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