Исследование диэлектрических функций слоя наночастиц Ag на кремнии с помощью спектроэллипсометрии и спектрофотометрии

An investigation of the optical characteristics of a layer of Ag nanoparticles deposited from an AgNO3 solution on the surface of single-crystal Si is presented. The measurements were carried out using spectroscopic ellipsometry and spectrophotometry at the same tilt angle and sample probe location in a wide spectral range from 200 to 1700 nm. From the obtained experimental data, the parameters of the Drude-Lorentz model and the complex dielectric function were determined, which was compared with the pseudo-dielectric function. Both dependences revealed resonances of a bulk plasmon near the energy E = 3.8 eV, while a localized plasmon was detected in the pseudo-dielectric function at E = 1.65 eV, and in the dielectric function at E = 1.84 eV.

Theoretical and experimental investigation of two-layer circular patch antenna excited by a coaxial probe

In this article, we present two efficient closed-form models to examine thoroughly the dependence of resonant frequency, quality factor, probe reactance, input impedance, bandwidth, and gain on parameters such as patch radius, probe location, substrate electrical parameters, and air gap of a coax probe-fed circular patch antenna. The implementation of these models is very easy and the computation cost is very low. The proposed models show excellent agreements with experimental and simulation results. We have also investigated experimentally the gain patterns of a suspended substrate circular patch antenna.

The Importance of PbtO2 Probe Location for Data Interpretation in Patients with Intracerebral Hemorrhage

Background/objective Monitoring of brain tissue oxygen tension (PbtO2) provides insight into brain pathophysiology after intracerebral hemorrhage (ICH). Integration of probe location is recommended to optimize data interpretation. So far, little is known about the importance of PbtO2 catheter location in ICH patients. Methods We prospectively included 40 ICH patients after hematoma evacuation (HE) who required PbtO2-monitoring. PbtO2-probe location was evaluated in all head computed tomography (CT) scans within the first 6 days after HE and defined as location in the healthy brain tissue or perilesional when the catheter tip was located within 1 cm of a focal lesion (hypodense or hyperdense). Generalized estimating equations were used to investigate levels of PbtO2 in relation to different probe locations. Results Patients were 60 [51–66] years old and had a median ICH-volume of 47 [29–60] mL. Neuromonitoring probes remained for a median of 6 [2–11] days. PbtO2-probes were located in healthy brain tissue in 18/40 (45%) patients and in perilesional brain tissue in 22/40 (55%) patients. In the acute phase after HE (0–72 h), PbtO2 levels were significantly lower (21 ± 12 mmHg vs. 29 ± 10 mmHg, p = 0.010) and brain tissue hypoxia (BTH) was more common in the perilesional area as compared to healthy brain tissue (46% vs. 19%, adjOR 4.0, 95% CI 1.54–10.58, p = 0.005). Episodes of BTH significantly decreased over time in patients with probes in perilesional location (p = 0.001) but remained stable in normal appearing area (p = 0.485). A significant association between BTH and poor functional outcome was only found when probes were located in the perilesional brain tissue (adjOR 6.6, 95% CI 1.3–33.8, p = 0.023). Conclusions In the acute phase, BTH was more common in the perilesional area compared to healthy brain tissue. The improvement of BTH in the perilesional area over time may be the result of targeted treatment interventions and tissue regeneration. Due to the localized measurement of invasive neuromonitoring devices, integration of probe location in the clinical management of ICH patients and in research protocols seems mandatory.

Time-locked inhibition of covert orienting

It is well known that visual transients can abolish the execution of an eye movement about 90 ms later, a phenomenon known as saccadic inhibition (SI). But it is not known if the same inhibitory process might influence covert orienting in the absence of saccades, and consequently alter visual perception. We measured orientation discrimination performance in 14 participants during a covert orienting task (modified Posner paradigm) in which an uninformative exogenous visual cue preceded the onset of an oriented probe stimulus by 120 to 306 ms. In half of the trials the onset of the probe was accompanied by a brief irrelevant flash, a visual transient that would normally induce SI in an overt task. We report a SI-like time-specific covert inhibition effect in which the irrelevant flash impaired orientation discrimination accuracy only when the probe followed the cue between 165 to 265 ms. The interference was more pronounced when the cue was incongruent with the probe location. We suggest that covert orienting may be susceptible to similar inhibitory mechanisms that generate SI in overt orienting, although the precise time course and mechanisms of this novel effect require further characterisation.

Active Actuating of a Simply Supported Beam with the Flexoelectric Effect

Piezoelectric materials with the electro-mechanical coupling effect have been widely utilized in sensors, dampers, actuators, and so on. Engineering structures with piezoelectric actuators and sensors have provided great improvement in terms of vibration and noise reduction. The flexoelectric effect—which describes the coupling effect between the polarization gradient and strain, and between the strain gradient and electric polarization in solids—has a fourth-rank order tensor electro-mechanical coupling coefficient, and in principle makes the flexoelectricity existing in all insulating materials and promises an even wider application potential in vibration and noise control. In the presented work, a flexoelectric actuator was designed to actuate a simply supported beam. The electric field gradient was generated by an atomic force microscopy probe. Flexoelectric control force and moment components could be induced within the flexoelectric control layer. As flexoelectricity is size-dependent, the key parameters that could affect the actuating effect were examined in case studies. Analytical results showed that the induced flexoelectric control moment was strongly concentrated at the probe location. The controllable transverse displacement of the simply supported beam was calculated with the modal expansion method. It was found that the controllable transverse displacement was dependent on the probe location as well.

Meibography guided intraductal meibomian gland probing using real-time infrared video feed

PurposeTo evaluate use of infrared meibography video to visualise meibomian gland probing and correlate probe findings of intraductal space with meibography images.MethodsVideos were reviewed and probe findings recorded of 996 probed gland orifices from 38 lower lids.Results996/997 (99.9%) of gland orifices were successfully probed with 91.8% revealing probe location. There were no false passages. 14% (140/997) of all gland orifices showed whole gland atrophy (WGA) with 99.3% (139/140) probed to 1 mm. Cumulative probe findings for all WGA (not differ significantly from non-WGA) showed 106 (76%), 21 (15%) and 12 (9%) glands with fixed, non-fixed and no resistance (NR), respectively. Lids without WGA showed increased NR/total glands probed while lids with WGAs (≥5) showed increased NR/WGA compared with lids with only 1–4 WGAs (p=0.011, p=0.005, respectively, Mann-Whitney U test) suggesting bimodal NR profile. Visualisation of microtube placement was successfully obtained for therapeutic injections and retrieval of meibum specimens.ConclusionVideo confirmed intraductal location and safety of devices. For 73% of non-WGA and 76% of WGAs as well as proximal ducts of glands with proximal atrophy, probing released fixed resistance restoring ductal integrity. A bimodal profile of NR suggests it is found with less diseased gland ducts as well as more advanced atrophic gland disease. Gland and ducts appeared flexible but not distendable while periglandular tissue appeared spongy. Visualisation of devices enables whole or localised gland therapy and meibum specimen retrieval, elegantly raising future research, therapeutic and regenerative opportunities.