Mechanism of Defects and Electrode Structure on the Performance of AlN-based Metal Semiconductor Metal Detectors

We used the metal-organic chemical vapor deposition(MOCVD) method to grow AlN material on a c-plane sapphire substrate and fabricate an AlN-based metal-semiconductor-metal (MSM) detector. Analyzing the influence mechanism of different dislocation densities in AlN materials and detector electrode structure on the detector performance, it was found that the lower the dislocations can effectively reduce the dark current of the detector under zero bias voltage, and help improve the performance of the detector. The study also found that when the finger spacing of the detector remained the same and the finger width increased, the efficiency of the detector decreased, while the response time of the detector increased, when the finger width of the detector electrodes remained unchanged and the finger spacing increased, the response time of the detector increased. Therefore, the electrode finger width and finger spacing must be compromised in the design of the electrode structure to improve the performance of the AlN-based MSM detector.

A model for screen utility to predict the future of printed solar cell metallization

Fine line screen printing for solar cell metallization is one of the most critical steps in the entire production chain of solar cells, facing the challenge of providing a conductive grid with a minimum amount of resource consumption at an ever increasing demand for higher production speeds. The continuous effort of the industrial and scientific community has led to tremendous progress over the last 20 years, demonstrating an average reduction rate for the finger width of approximately 7 µm per year with the latest highlight of achieving widths of 19 µm. However, further reductions will become a major challenge because commonly used metal pastes are not able to penetrate arbitrary small screen opening structures. Therefore, this study introduces the novel dimensionless parameter screen utility index SUI which quantifies the expected printability of any 2-dimensional screen architecture in reference to a given paste. Further, we present a full theoretical derivation of the SUI, a correlation to experimental results and an in-depth simulation over a broad range of screen manufacturing parameters. The analysis of the SUI predicts the point when commonly used wire materials will fail to provide sufficient meshes for future solar cell metallization tasks. Therefore, novel wire materials (e.g. the use of carbon nanotubes) with very high ultimate tensile strengths are discussed and suggested in order to fulfill the SUI requirements for printing contact fingers with widths below 10 µm. We further analyze economic aspects of design choices for screen angles by presenting an analytical solution for the calculation of mesh cutting losses in industrial screen production. Finally, we combine all aspects by presenting a generalized approach for designing a 2-dimensional screen architecture which fulfills the task of printing at a desired finger width.

The evaluation of maximum condyle-tragus distance can predict difficult airway management without exposing upper respiratory tract; a prospective observational study

Background Routine preoperative methods to assess airway such as the interincisor distance (IID), Mallampati classification, and upper lip bite test (ULBT) have a certain risk of upper respiratory tract exposure and virus spread. Condyle-tragus maximal distance(C-TMD) can be used to assess the airway, and does not require the patient to expose the upper respiratory tract, but its value in predicting difficult laryngoscopy compared to other indicators (Mallampati classification, IID, and ULBT) remains unknown. The purpose of this study was to observe the value of C-TMD to predict difficult laryngoscopy and the influence on intubation time and intubation attempts, and provide a new idea for preoperative airway assessment during epidemic. Methods Adult patients undergoing general anesthesia and tracheal intubation were enrolled. IID, Mallampati classification, ULBT, and C-TMD of each patient were evaluated before the initiation of anesthesia. The primary outcome was intubation time. The secondary outcomes were difficult laryngoscopy defined as the Cormack-Lehane Level > grade 2 and the number of intubation attempts. Results Three hundred four patients were successfully enrolled and completed the study, 39 patients were identified as difficult laryngoscopy. The intubation time was shorter with the C-TMD>1 finger group 46.8 ± 7.3 s, compared with the C-TMD<1 finger group 50.8 ± 8.6 s (p<0.01). First attempt success rate was higher in the C-TMD>1 finger group 98.9% than in the C-TMD<1 finger group 87.1% (P<0.01). The correlation between the C-TMD and Cormack-Lehane Level was 0.317 (Spearman correlation coefficient, P<0.001), and the area under the ROC curve was 0.699 (P<0.01). The C-TMD < 1 finger width was the most consistent with difficult laryngoscopy (κ = 0.485;95%CI:0.286–0.612) and its OR value was 10.09 (95%CI: 4.19–24.28), sensitivity was 0.469 (95%CI: 0.325–0.617), specificity was 0.929 (95%CI: 0.877–0.964), positive predictive value was 0.676 (95%CI: 0.484–0.745), negative predictive value was 0.847 (95%CI: 0.825–0.865). Conclusion Compared with the IID, Mallampati classification and ULBT, C-TMD has higher value in predicting difficult laryngoscopy and does not require the exposure of upper respiratory tract. Trial registration The study was registered on October 21, 2019 in the Chinese Clinical Trial Registry (ChiCTR1900026775).

The evaluation of maximum condyle-tragus distance can predict difficult airway management without exposing upper respiratory tract: a prospective observational study

Background: Routine preoperative methods to assess airway such as the interincisor distance(IID), Mallampati classification, and the upper lip bite test(ULBT) have a certain risk of upper respiratory tract exposure and virus spread. The condyle-tragus maximal distance(C-TMD) can be used to assess the airway, and the assessment method does not require the patient to expose the upper respiratory tract, but its value in predicting difficult laryngoscopy compared to other indicators (Mallampati classification, IID, and ULBT) remains unknown. The purpose of this study was to observe the value of C-TMD to predict difficult laryngoscopy and the influence on intubation time and intubation attempts, and provide a new idea for preoperative airway assessment during epidemic. Methods: We enrolled adult patients who underwent general anesthesia and tracheal intubation. The IID, Mallampati classification, ULBT, and the C-TMD of each patient were evaluated prior to the initiation of anesthesia. The primary outcome was intubation time. The second outcome were difficult laryngoscopy defined as the Cormack-Lehane Level > grade 2 and the number of intubation attempts. Results: A total of 304 patients were successfully included in the study, 39 patients were identified as difficult laryngoscopy. The intubation time was shorter with the C-TMD＞1 finger group 46.8±7.3s, compared with the C-TMD＜1 finger group 50.8±8.6s (p＜0.01). First attempt success rate was higher in the C-TMD＞1 finger group 98.9% than in the C-TMD＜1 finger group 87.1% (P＜0.01). The correlation between the C-TMD and Cormack-Lehane Level was 0.317(Spearman correlation coefficient, P＜0.001), and the area under the ROC curve was 0.699(P＜0.01). The C-TMD <1 finger width was the most consistent with difficult laryngoscopy (κ=0.485;95%CI:0.286-0.612) and its OR value was 10.09(95%CI: 4.19-24.28), sensitivity was 0.469(95%CI: 0.325-0.617), specificity was 0.929(95%CI: 0.877-0.964), positive predictive value was 0.676 (95%CI: 0.484-0.745), negative predictive value was 0.847(95%CI :0.825-0.865).Conclusion: Compared with the IID , Mallampati classification and ULBT, the C-TMD has higher value in predicting difficult laryngoscopy and does not require the exposure of upper respiratory tract.Trial registration: The study was registered on October 21, 2019 in the Chinese Clinical Trial Registry (ChiCTR1900026775).

Evaluation of finger millet [Eleusine coracana (L.) Gaertn.] accessions using agro-morphological characters

The study was conducted at village level in-situ center, Jawhar block of Palghar district of Maharashtra during the year 2017 and 2018 to characterize 20 accessions of finger millet. Data was collected on morphology, plant growth and yield contributing characters. Traits like erect growth habit (80 percent); semi-compact ear (60 percent); partially enclosed seeds by glumes (60 percent) and light brown colour of seed (75 percent) was found dominant among studied accessions. The results indicated that studied landraces exhibited variability in finger number (6 to 14), finger length (7 to 16 cm) and maturity days (85 to 117). The results of study also showed that productive tiller number was most varied trait (29.37 percent), followed by ear head length (21.98 percent) and finger number (19.42 percent). Among the studied traits, finger width showed the lowest variation (7.65 percent). Analysis of variance showed that all the characters were highly significant among the accessions. This potential gene pool needs to be conserved and may be explored for crop improvement in future.

Dissolution-driven convection in a heterogeneous porous medium

Motivated by subsurface carbon sequestration, an experimental investigation of dissolution-driven Rayleigh–Darcy convection using two miscible fluids in a Hele-Shaw cell is conducted. A thin horizontal layer of circular impermeable discs is inserted to create an environment with heterogeneous and anisotropic permeability. The Sherwood number that measures the convective mass transfer rate between two fluids at the interface is linked to different parameters of the disc layer, including the disc size, spacing, layer permeability and its relative height with respect to the fluid interface. It is surprising that the convective mass transfer rate in our configuration is dominated by the disc spacing, but almost independent of either the disc size or the mean permeability of the layer. To explain this dependence, the convective mass transfer rate is decomposed into the number, velocity and density contrast of fingers travelling through the disc layer. Both the number and density contrast of fingers show dependences on the disc layer permeability, even though the product of them, the mass transfer rate, does not. In addition, the density contrast also shows a non-monotonic dependence on the disc spacing. The transition point is at a spacing that is close to the finger width. Based on this observation, a simple model based on mixing and scale competition is proposed, and it shows an excellent agreement with the experimental results.

Customization of a 3D Printed Prosthetic Finger Using Parametric Modeling

Prosthetic limbs and assistive devices require customization to effectively meet the needs of users. Despite the expense and hassle involved in procuring a prosthetic, 56% of people with limb loss end up abandoning their devices [1]. Acceptance of these devices is contingent on the comfort of the user, which depends heavily on the size, weight, and overall aesthetic of the device. As seen in numerous applications, parametric modeling can be utilized to produce medical devices that are specific to the patient’s needs. However, current 3D printed upper limb prosthetics use uniform scaling to fit the prostheses to different users. In this paper, we propose a parametric modeling method for designing prosthetic fingers. We show that a prosthetic finger designed using parametric modeling has a range of motion (ROM) (path of the finger tip) that closely aligns with the digit’s natural path. We also show that the ROM produced by a uniformly scaled prosthetic poorly matches the natural ROM of the finger. To test this, finger width and length measurements were collected from 50 adults between the ages of 18–30. It was determined that there is negligible correlation between the length and width of the index (D2) digit among the participants. Using both the highest and the lowest length to width ratio found among the participants, a prosthetic finger was designed using a parametric model and fabricated using additive manufacturing. The mechanical design of the prosthetic finger utilized a crossed four bar linkage mechanism and its ROM was determined by Freudenstein’s equations. By simulating the different paths of the fingers, we demonstrate that parametrically modeled fingers outperform uniformly scaled fingers at matching a natural digit’s path.