Metamaterials have been designed to achieve a wide range of functionalities. Metamaterial absorbers are of particular interest for various applications such as infrared detectors, emissivity ...coatings, and photovoltaic cells. Various metamaterial platforms have been demonstrated to achieve perfect absorption and several attempts have been made to extend the absorption bandwidth of such devices. We demonstrate a broadband infrared absorber using an asymmetric Fabry–Perot cavity consisting of a monolithically fabricated two-layer metasurface. Superoctave optical absorption is achieved by tailoring the structure of the metasurface layers and the thickness of the cavity. The device yields absorptance of over 80% from λ = 4–16 μm, while maintaining the performance over a wide range of incident angles. In contrast to most metamaterial absorbers, our metasurface layers are made of customized indium tin oxide (ITO), conferring the advantage of CMOS compatibility compared to previous approaches using noble metals.
Modulus of resilience, the measure of a material’s ability to store and release elastic strain energy, is critical for realizing advanced mechanical actuation technologies in ...micro/nanoelectromechanical systems. In general, engineering the modulus of resilience is difficult because it requires asymmetrically increasing yield strength and Young’s modulus against their mutual scaling behavior. This task becomes further challenging if it needs to be carried out at the nanometer scale. Here, we demonstrate organic–inorganic hybrid composite nanopillars with one of the highest modulus of resilience per density by utilizing vapor-phase aluminum oxide infiltration in lithographically patterned negative photoresist SU-8. In situ nanomechanical measurements reveal a metal-like high yield strength (∼500 MPa) with an unusually low, foam-like Young’s modulus (∼7 GPa), a unique pairing that yields ultrahigh modulus of resilience, reaching up to ∼24 MJ/m3 as well as exceptional modulus of resilience per density of ∼13.4 kJ/kg, surpassing those of most engineering materials. The hybrid polymer nanocomposite features lightweight, ultrahigh tunable modulus of resilience and versatile nanoscale lithographic patternability with potential for application as nanomechanical components which require ultrahigh mechanical resilience and strength.
Patterning of materials at single nanometer resolution allows engineering of quantum confinement effects, as these effects are significant at these length scales, and yields direct control over ...electro‐optical properties. Silicon is by far the most important material in electronics, and the ability to fabricate Si‐based devices of the smallest dimensions for novel device engineering is highly desirable. The work presented here uses aberration‐corrected electron‐beam lithography combined with dry reactive ion etching to achieve both: patterning of 1 nm features and surface and volume plasmon engineering in Si. The nanofabrication technique employed here produces nanowires with a line edge roughness (LER) of 1 nm (3σ). In addition, this work demonstrates tuning of the Si volume plasmon energy by 1.2 eV from the bulk value, which is one order of magnitude higher than previous attempts of volume plasmon engineering using lithographic methods.
1 nm resolution Si patterning is achieved using aberration‐corrected electron‐beam lithography (AC‐EBL) and reactive ion etching, techniques compatible with Si technology processes, resulting in features with a line edge roughness of 1 nm. AC‐EBL is also used to tune the Si volume plasmon energy as a function of nanostructure geometry, demonstrating control of electro‐optical properties of nanostructures “by design.”
The interband GaSb-based diode lasers emitting simultaneously in two narrow bands separated by either ~1.6 or ~3.3 THz were designed, fabricated and characterized. The device active region contained ...one asymmetric tunnel-coupled double quantum well with separation between two lowest electron subbands controlled by thickness of the tunnel barrier. The Y-branch 6 th order distributed Bragg reflector devices have been fabricated with either deep or shallow etched ridge waveguides. The increase of the deeply etched ridge waveguide width from 10 to <inline-formula> <tex-math notation="LaTeX">20~\mu \text{m} </tex-math></inline-formula> improved laser threshold and efficiency thanks to reduction of the relative role of the sidewall defect recombination. Further improvement of the device performance parameter was achieved by shallow etching. The shallow etched lasers with stable dual-wavelength emission spectrum generated 100 mW of continuous wave output power at 20 °C.
Cascade pumping of type-I quantum well gain sections was utilized to increase output power and efficiency of GaSb-based diode lasers operating in spectral region from 1.9 to 3.3 μm. Coated devices ...with ~100-μm-wide aperture and 3-mm-long cavity demonstrated continuous wave (CW) output power of 1.96 W near 2 μm, 980 mW near 3 μm, 500 mW near 3.18 μm, and 360 mW near 3.25 μm at room temperature. The corresponding narrow ridge lasers with nearly diffraction limited beams operate in CW regime with tens of mW of output power up to 60 °C. Two step shallow/deep narrow/wide ridge waveguide devices showed lower threshold currents and higher slope efficiencies compared to single step narrow ridge lasers. Laterally coupled DFB lasers mounted epi-up generated above 10 mW of tunable single frequency CW power at 20 °C near 3.22 μm.
Purpose
Based on social exchange theory and the substitutes for leadership theory, this paper aims to investigate whether an organization’s high-commitment HRM strategy can substitute for the effect ...of servant leadership in promoting employees’ affective commitment, psychological empowerment and intent to remain with the organization.
Design/methodology/approach
This study’s hypotheses were tested with moderation and mediation analyses conducted on a sample of 172 Chinese employees.
Findings
The results show significant negative interaction effects between high-commitment HRM systems and servant leadership, such that high levels of one will reduce the positive effect of the other on affective commitment and psychological empowerment. Further, the effects of high-commitment HRM systems and servant leadership on turnover intentions are mediated through affective commitment and psychological empowerment. Finally, support was found for a mediated moderation model where the negative interaction effect between high-commitment HRM systems and servant leadership on turnover intentions is mediated through affective commitment.
Practical implications
The results of this study can help practitioners identify alternative means to influence employees’ positive attitudes and work motivation when implementing high-commitment HRM systems is not feasible for the organization.
Originality/value
This study contributes to the leadership literature by providing evidence supporting the substitutes for leadership theory and describing the specific conditions under which this theory is valid, as well as contributing to the HRM literature by examining the dynamic interaction of HRM and leadership.
We report a large-area fabrication method to prepare chiral substrates patterned with arrays of multilayer, three-dimensional nanostructures using a combination of nanoimprint lithography and ...glancing angle deposition. Several structures are successfully fabricated using this method, including L-shaped, twisted arc and trilayer twisted Au nanorod structures, demonstrating its generality. As one typical example, arrays of L-shaped nanostructures, consisting of two layers of orthogonally oriented Au nanorods separated by a Ge dielectric layer in the thickness direction, exhibit giant optical chirality in the infrared region with an experimentally achieved g-factor as high as 0.38. Electromagnetic simulations show that the optical chirality results from plasmon hybridization between the two orthogonal Au segments. To demonstrate scalability, a 1 cm2 chiral substrate is fabricated with uniform chiral optical property. This method combines both high throughput and precise geometrical control and is therefore promising for applications of chiral metamaterials.
INTRODUCTION:
The prevalence of hospital-acquired Clostridioides difficile infection (CDI) in a healthcare facility is directly correlated with the efficacy of infection prevention practices. ...Although associations are well documented between CDI incidence and the exposure to antibiotics and acid-reducing medications, to effectively prevent CDI, all risk factors for transmission must be investigated. This study will demonstrate how innovative practice strategies, created by a multidisciplinary CDI Prevention Team, that were introduced and sustained over a 20 month period of time, resulted in dramatic improvements in CDI rates.
METHODS:
A cohort of 52 patients with a diagnosis of CDI were chosen for the purpose of determining the efficacy of an innovative, multi-disciplinary intervention. The subject lists were obtained from the NHSN reported cases. The study was comprised of three phases: Pre-intervention Period, Transitional Period, and Intervention Period. During the Transitional Period, the innovative, multidisciplinary intervention was introduced, consisting of a series of preventive strategies aimed at eradicating CDI in the patient population and the hospital's physical environment.
RESULTS:
Of the 52 patients studied with CDI, 23 patients were Community-Onset while 29 patients were Hospital-Acquired. With each study period, CDI HAI's were shown to decrease as the innovative practice strategies were incorporated into practice. In fact, during the Pre-intervention Period, there were 17 HAI's with 9461 patient days resulting in a 1.79 infection rate; the Transitional Period, 6 HAI'S/14,697 patient days resulting in a 0.40 infection rate; and the Intervention Period, 6 HAI's/33,603 patient days resulting in a 0.17 infection rate. In summary, the annual CDI rate decreased by 62% over one year after implementation of multidisciplinary interventions, demonstrating a statistically significant trend of reducing the infection rates (
P
value < 0.0001).
CONCLUSION:
The data analysis identified well-known CDI risk factors that included residing in long-term care institutions, acid suppressive therapy, prior antibiotic use and the management of the patient's environment. The incorporating of a variety of strategies such as: hand washing, isolation precautions, electronic medical record features, diagnostic testing parameters, UV technology, disposable meal trays, cutlery and plates, and managing the patient's environment, could serve as a paradigm for reducing CDI in a Community-based hospital.
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