Lot Of Defects Research Articles

Deep Metal-Assisted Chemical Etching Using a Porous Monolithic AgAu Layer to Develop Neutral-Colored Transparent Silicon Photovoltaics

Neutral-colored transparent crystalline silicon photovoltaics (c-Si TPV) was reported as remarkable building-integrated photovoltaics (BIPV) due to its high efficiency with excellent transmittance. Deep reactive ion etching (DRIE) is required to fabricate this photovoltaics where the microhole-shaped light transmission windows were placed on bare crystalline silicon (c-Si, ca. 200 μm thickness) to transmit all visible wavelengths, which causes both high fabrication cost and the plasma damage on Si surface. A prominent replaceable method is metal-assisted chemical etching (MACE) which occurs through the redox reaction at the Si/metal catalyst/etchant solution interfaces because it features simplicity, versatility, and cost-effectiveness. However, the metal catalysts that grow via electroless deposition are deposited as particle-form, which act individually during MACE and induce the uneven MACE, thus yielding a lot of defects on the resultant Si.Here, we report deep MACE using a porous monolithic AgAu layer on c-Si for fabricating c-Si TPV. To prevent the uneven etching of c-Si by Ag particles, the porous monolithic Ag layer is developed by introducing acetonitrile (AN) to enhance the interaction between the c-Si surface and Ag precursor. This results in cooperative motion during MACE, as confirmed by microscopic observation, surface area measurement, and computational simulations. The durability of this Ag catalyst can be further improved by passivation with Au via galvanic replacement (i.e., the porous monolithic AgAu layer), thereby preventing indiscriminate defect generation. Thus, the fabricated c-Si TPV using MACE and a porous monolithic AgAu layer exhibits high performance of 13.0% with 20% neutral-colored transparency, representing results superior to those obtained with samples fabricated by DRIE (11.5%). Figure 1

X-Linked Intellectual Disability with NEXMIF Gene Mutation and Developmental Delay with GNAO1 Gene Mutation: Case Report

X-linked intellectual disability (XLID) is a genetically heterogeneous disorder. Currently, 162 genes linked to XLID have been found, but the cause of XLID is still unclear. While the GNAO1 gene is crucial for hypotonia, epilepsy, developmental delay, and movement disorders, the NEXMIF gene, also known as KIAA2022, has associations with XLID, autism, and epilepsy. The subject of the study, a 5-year-old girl has lots of congenital defects, including a cleft palate, anal atresia, hypotonia in her lower limbs, and thumb missing. A variety of eye abnormalities, such as scoliosis, finger malformations, and craniofacial dysmorphism. Radiological tests revealed substantial heart problems, bilateral renal hypoplasia, and brain abnormalities. She met milestones more later than her contemporaries, indicating clear developmental deficits. The NEXMIF and GNAO1 genes both include heterozygous frameshift variants that were discovered through genetic research using next-generation sequencing. The complex and varied clinical signs of XLID are shown in this case. The clinical picture is further complicated by the co-occurrence of mutations in the NEXMIF and GNAO1 genes, which emphasizes the need for an approach to offer suitable therapy solutions. Future studies are necessary to understand the complex interactions between these genes and how they affect XLID and related symptoms.

Analysis of ionic defect distribution on perovskite photodetector by temperature-dependent deep level transient spectroscopy

The High-efficiency Organohalide perovskites solar cells are produced via a solution-based method. Thus, a lot of defects are inevitable generated during fabrication processes, which are the main factors that affect the efficiency and long-term stability. The defect has been linked to the observation of reduce device stability against degradation and it can also create mid-gap states in a band structure as well act as recombination centers. Although the efficiency of the perovskite solar cells (PSCs) has been improved by curing defects using various passivation methods, deeply trapped defects in the perovskite layer have not been systematically studied, and their function is still unclear. In this study, we perform temperature-dependent deep-level transient spectroscopy (T-DLTS) measurements on PSCs, ionic defect parameters (activation energy, trap density, diffusion constants) for each observed ionic species were compared in different PSCs.

Effect of Laser Heat Input on the Microstructures and Low-Cycle Fatigue Properties of Ti60 Laser Welded Joints

In this paper, the effects of laser heat input on the microstructures, tensile strength, and fatigue properties of Ti60 laser welded joints were investigated. The results show that with the increase in laser heat input, the macro morphology of the weld zone (WZ) changes from the Y-type to X-type. In the Y-type WZ, the porosity defects are almost eliminated. In contrast, there are a lot of porosity defects in the lower part of the X-type WZ. The microstructure of the base metal (BM) comprises equiaxed α phases, and β phases are mainly distributed at the boundaries of α phases. The heat-affected zone (HAZ) is comprised of α phases and acicular α′ phases, while the WZ mainly contains acicular α′ phases. With the increase in laser heat input, the quantity of the α phase gradually decreases and the acicular α′ phase gradually increases in the HAZ, and the size of the acicular α′ phase in the WZ gradually decreases. Due to the different microstructures, the hardness of BM is lower than the HAZ and WZ under different laser heat input conditions. In the tensile tests and low-cycle fatigue tests, the welded joints are fractured in BM. The porosity defects do not have decisive effects on the tensile and low-cycle fatigue properties of Ti60 laser welded joints.

Influences of curing depth and layer thickness on forming accuracy and mechanical properties of biphasic calcium phosphate bioceramics fabricated by vat photopolymerization

Vat photopolymerization (VPP) is a high potential and efficient method for fabricating advanced ceramics. However, the selection of printing strategy importantly determines the geometrical accuracy and mechanical strength of ceramic parts prepared by VPP. In this study, the effects of the curing depth (Cd) to layer thickness (Lt) ratio and Lt on forming accuracy, microstructures, mechanical properties, surface roughness of biphasic calcium phosphate (BCP) bioceramic green bodies and sintered bodies were investigated. When the Cd/Lt ratio was smaller than 4.0, and the Lt was not over 50 μm, the green bodies presented high forming accuracy (the dimension errors ˂ 3.50 %). Inappropriate Cd/Lt and Lt caused lots of defects including different types of cracks and delamination on green bodies and sintered bodies, and impaired their mechanical strength. The optimal Cd/Lt ratio and Lt were obtained to be 4.0 and 50 μm, in which parameters there were few cracks and delamination on the sintered BCP bioceramics. The flexural strength and the fracture toughness of sintered BCP increased when the Cd/Lt ratio increased from 3.0 to 4.0. However, the flexural strength and the fracture toughness decreased when the Cd/Lt ratio further increased to 5.0. The flexural strength of sintered BCP increased at first and then decreased when the Lt increased from 25 μm to 50 μm, and the fracture toughness and hardness of BCP decreased continually. The flexural strength of sintered BCP showed a maximum value of 113.21 MPa, and the maximum fracture toughness was 0.71 MPa∙m1/2. The elastic modulus and hardness of sintered BCP also reached 24.16 GPa and 3.04 GPa, respectively. The printing surface roughness of BCP bioceramics decreased when the Cd/Lt ratio or Lt increased. The lateral surface roughness decreased with the increase of Cd/Lt ratio, and increased with the increase of Lt. This new result provides a clear printing strategy for fabricating ceramics with high geometrical accuracy and mechanical properties by VPP technique.

Modifying the CNTs with high dielectric loss NiCo2O4 to enhance the electromagnetic wave absorption properties

Decorating the CNTs with dielectric loss material is an effective means of enhancing electromagnetic wave absorption properties. In this work, we synthesized high dielectric loss NiCo2O4 nanoparticles on CNTs through hydrothermal method. By adjusting hydrothermal time, the NiCo2O4/CNTs with different NiCo2O4 content were obtained. The nucleation and growth of NiCo2O4 nanoparticles would cause a lot of defects and heterogeneous interfaces on CNTs, which influences the conduction loss and polarization loss of CNTs. Therefore, adjusting the content of NiCo2O4 in CNTs is an efficient path to enhance its absorbing performance. When the content of NiCo2O4 is 45.05 wt%, the reflection loss of NiCo2O4/CNTs reaches −43.2 dB, and the effective absorption bandwidth can be up to 3.3 GHz. It proves that NiCo2O4/CNTs has potential to be a high quality absorbing agent.

Trap-Induced Long-Lived Internal Charge Separation in Sn-Doped MAPbBr3 Perovskite Films.

Sn-doped lead halide perovskites (LHPs) have attracted considerable attention for their lower bandgap and lower toxicity. While it is well-established that Sn doping easily introduces a lot of structural defects into LHP films, the extent to which these defects impact carrier dynamics has yet to be fully elucidated. Herein, we take Sn-doped MAPbBr3 films as an example to explore the influence of Sn doping on their carrier dynamics. The results show that Sn doping can simultaneously introduce many fillable electron traps and unfillable hole traps, consequently instigating an ultrafast carrier capture process. This further elicits long-lived internal charge separation between band edge and trap states or between two kinds of trap states, thereby enabling these carriers to persist for up to ∼2.6 μs. Our findings suggest that Sn doping potentially serves as an effective strategy to prolong the carrier lifetime in LHPs, which could pave the way for potential applications within Sn-based perovskites.

In-situ capture defects through molecule grafting assisted in coal-based hard carbon anode for sodium-ion batteries

Sodium-ion batteries is not essential but also potential to support energy storage system due to the low cost. It's worth noting that low price and high carbon production helps coal extraordinary promise as hard carbon precursor. However, low initial coulombic efficiency (ICE) and practical Na+ storage specific capacity barrier their application owing to lots of defects. Herein, a grafting method is proposed to decrease defects, introducing glucose with simple one step carbonization process. Utilizing the reaction between glucose and coal reduces the defects, which generates a high ICE with less irreversible sodium ion consumption. Meanwhile the expanded carbon layer spaces enable the fast sodium ions transfer, leading to an optimized sodium storage performance. The grafted glucose obviously decreases the defects during the carbonization process and contributes extra sodium storage capacity. The optimal CG0.1 exhibits higher reversible capacity of 293 mAh∙g−1 and ICE of 84 % than pristine coal pyrolytic carbon (250 mAh∙g−1 and 79 %). Besides, it also delivers outstanding capacity retention with 95.3 % and 95.8 % after 1000 cycles at 0.3 A∙g−1 (240 mAh∙g−1) and at 1 A∙g−1 (207 mAh∙g−1).

Acceptance Sampling Plans based on Percentiles of Exponentiated Inverse Kumaraswamy Distribution

Objectives: To prepare the percentile-based acceptance sampling plans for the Exponentiated Inverse Kumaraswamy Distribution (EIKD) at a specific truncation time to inspect the defective lots corresponding to the desired acceptance level. Methods: The failure probability value is estimated using the cumulative probability function F(.) at time ‘t’ which is converted in terms of the scale parameter σ as 100th percentile using quantile function. The minimum size of the sample, Operating Characteristic (OC) and the minimum ratios are calculated for a required levels of consumer’s as well as producer’s risk. Findings: The percentile-based sampling plans are obtained through the minimal size of the sample ‘n’ under a truncated life test with a target acceptance number c in a manner that the proportion of accepting a lot which is not good (consumer’s risk) would not be more than . These values are calculated at The function of probability of acceptance for variations in the quality of a lot (OC function) L(p) of the sample plan are evaluated for the acceptance values of c=1 and c=5. The minimum ratio values are calculated for the acceptability of the lot with producers’ risk of using the sampling plan. Novelty: The modernity of this study is the designing of the acceptance sampling plans to a non-normal data using an asymmetrical distribution that has all three shape parameters. Also, the monitor of the implementation and suitability of statistical quality control and process control aspects using Exponentiated Inverse Kumaraswamy Distribution when compared to other asymmetrical distributions which has at least one scale parameter. Keywords: Sampling plans, Consumer's risk, Operating characteristics function, Truncated life tests, Producer's risk

Crater-free monolayer graphene above the 2D Si film on SiC(0001) formed via SiSn cointercalation and Sn deintercalation

When Si atoms are intercalated under the graphene-like zero layer (ZL) generated on the SiC(0001) substrate, the resulting quasi-free-standing monolayer graphene (QFMLG) has lots of crater-like defects due to a strong Si-C reaction. Here, a method for creating crater-free QFMLG above a two-dimensional Si film is investigated using scanning tunneling microscopy and photoemission spectroscopy. The method involves forming a SiSn interfacial film as a precursor via cointercalation performed by sequential Sn and Si deposition on the ZL at room temperature and annealing at 650–700 °C. The Sn atoms prevent reactive Si atoms from directly contacting the ZL, which would otherwise cause SiC defects. The sample is then annealed at 750 °C to selectively remove the Sn atoms from the SiSn interfacial film, leaving a well-ordered Si film. The SiSn film composed of a bottom Si layer and top Sn atoms has a short-range-ordered “2 × 2” or a long-range-ordered 2×7 superstructure depending on the annealing temperature and the Sn coverage. Both the superstructures are semiconducting and induce less n-doped QFMLG than the pure Si film.

The N-doped carbon coated Na3V2(PO4)3 with different N sources as cathode material for sodium-ion batteries: Experimental and theoretical study

NASICON (super ion conductor)-type Na3V2(PO4)3 (NVP) is considered to be one of the most promising cathode materials for sodium-ion batteries (SIBs) due to its good structural stability, fast Na+ diffusion coefficient, and excellent electrochemical properties. However, the poor intrinsic conductivity and electronic conductivity and severe volume shrinkage of NVP, resulting in serious limitations in the practical application of NVP materials. Carbon, especially N-doped carbon modification, is the most effective method and strategy to improve the conductivity of NVP. The study of N source and N content in carbon plays a very important role in improving the electronic properties. Herein, N-doped carbon coated NVP composites was synthesized via the classical sol-gel method using common, green and inexpensive urea and polyvinylpyrrolidone (PVP) as N sources, respectively. According to EIS tests and GITT tests, N-doped carbon layers with urea as the N source significantly improved the conductivity of the carbon layers and the Na+ diffusion kinetics. The effects of N-doped carbon layers on the electrode kinetics and electrochemical properties of NVP materials were investigated in detail. The optimized U-NC15@NVP composite exhibited a maximum discharge capacity of 114.2 mAh g−1 at 0.2C and 92.1% capacity retention after 400 cycles at 1C. When the optimal U-NC15@NVP electrode was selected to assemble a symmetric full cell, the reversible discharge capacity was 75.0 mAh g−1 after 100 cycles at 1C. The density functional theory (DFT) calculations establish that N-doped carbon can generate lots of active sites and external defects, which is beneficial to reduce the energy bandwidth of the carbon layer and thus improve the conductivity of the carbon layer. Additionally, it can also reduce the Na+ diffusion barrier and improve the adsorption energy for Na+. Experimental tests and theoretical calculations show that N-doped carbon can significantly increase the conductivity of the carbon layer and improve the electrochemical properties of NVP.

X-ray detection of ceramic packaging chip solder defects based on improved YOLOv5

It is of great significance to detect solder defects of ceramic packaging chips by X-ray detection to improve the quality of electronic products. However, the scale of the solder defects varies violently and there are a lot of tiny, dense, and long narrow defects, making it difficult to identify timely and accurately. To solve the issues mentioned above, an improved object detection model based on the YOLOv5 network, namely YOLO-STPN, is proposed in this paper. We add another prediction head to the original model to detect tiny solder defects effectively. In addition, the swin transformer block and convolutional block attention module are integrated into the path aggregation network, which improve the networks’ ability to identify dense and long narrow defects. The positive sample matching mechanism and the complete intersection over union (CIoU) loss are modified to make the model focus on long narrow defects. Experimental results of 10 types of ceramic packaging chips show that the mean average precision at 50 % IoU (mAP50) of YOLO-STPN is 10.05 % higher than the original YOLOv5 on average, while the decrease of frames per second (FPS) is acceptable. The proposed method has high accuracy and speed. Therefore, it is applicable to the real-time detection of chip packaging.

Amorphous Vanadium Oxides with Dual ion Storage Mechanism for High-Performance Aqueous Zinc ion Batteries.

Owing to the extremely limited structural deformation caused by the introduction of guest ions that their rigid structure can sustain, crystalline materials typically fail owing to structural collapse when utilized as electrode materials. Amorphous materials, conversely, are more resistant to volume expansion during dynamic ion transport and can introduce a lot of defects as active sites. Here, The amorphous polyaniline-coated/intercalated V2O5·nH2O (PVOH) nanowires are prepared by in situ chemical oxidation combined with self-assembly strategy, which exhibited impressive electrochemical properties because of its short-range ordered crystal structure, oxygen vacancy/defect-rich, improved electronic channels, and ionic channels. Through in situ techniques, the energy storage mechanism of its Zn2+/H+ co-storage is investigated and elucidated. Additionally, this work provides new insights and perspectives for the investigation and application of amorphous cathodes for aqueous zinc ion batteries.

Porous carbon nanosheets derived from two-dimensional Fe-MOF for simultaneous voltammetric sensing of dopamine and uric acid

It is of great significance for electrochemical sensors to simultaneously detect dopamine (DA) and uric acid (UA) related to biological metabolism. In this work, two-dimensional (2D) porous carbon nanosheets (CNS) was prepared as electrocatalysts to improve the sensitivity, the selectivity, and the detection limit of the simultaneous detection. First, 2D amorphous iron-metal organic frameworks (Fe-MOF) was synthesized with Fe3+ and terephthalic acid via a facile wet chemistry method at room temperature. And then, CNS was prepared by pyrolysis and pickling of Fe-MOF. CNS had large specific surface area, good electrical conductivity and lots of carbon defects. The response currents of the CNS modified electrode was larger than those of the control electrodes in the simultaneous determination. The simultaneous determination was measured via differential pulse voltammetry to reduce the effect of capacitive currents on quantitative analysis. The CNS modified electrodes showed high sensitivity and low detection limit for the simultaneous detection of DA and UA. The modified electrodes have been successfully used to detect DA and UA in normal human serum.

Dual-functionalized poly(ethylene oxide) for interface modification and addition of rubidium-doped CsPbBr3 perovskite composite emission layer to enhance brightness of perovskite light-emitting diodes

Metal halide perovskite as an emitter has extremely high color purity, but the generally poor morphology of the perovskite layer restricts the performance of the emitter. The additive of a suitable polymer can greatly boost the uniformity of the spin-coated perovskite film. The all-inorganic perovskite layer deposited by the solution method has a multi-crystalline structure. Besides, there are a lot of defects and grain boundaries on the surface, and the carriers will undergo non-radiative recombination at these defects. In this study, Cs1-xRbxPbBr3 was prepared by introducing Rb+ cations with smaller ionic radius to partially replace Cs+ cations, and combined with poly(ethylene oxide) (PEO) and (1,3,5-benzinetriyl)tris(1-phenyl-1-H-benzimidazole) (TPBi) blended composite film as the light-emitting layer, that can increase the film coverage and radiative recombination efficiency of the perovskite film. The polymer PEO was introduced as a buffer layer deposited on the poly-TPD hole transport layer (HTL) to to enhance the hydrophilicity and passivate the poly-TPD HTL/perovskites interface in order to obtain high-efficiency perovskite light-emitting diodes. By adjusting the concentration of the PEO buffer layer, the champion luminance and external quantum efficiency are 25650 cd/m2 and 0.844 %, respectively.

X-ray tomography of failure behaviors of arc welded AA2219 joints under tensile and cyclic loading

As one of the main structural materials widely used for the new generation of launch vehicles, the tensile properties and microstructural characterization of tungsten inert gas (TIG) welded 2219 aluminium alloy has been studied extensively. However, there are significant differences between fatigue fracture and tensile fracture modes. In this paper, the tensile and fatigue damage behaviors of arc-welded AA2219 joints were investigated in depth. Combined with the microstructure observation and fracture analysis done by using X-ray computed tomography, the main factors that affect the fatigue damage behavior are discussed. The results show that there are a large number of porosity defects in the weld zone, showing an aggregation distribution at the weld toe and weld pool line. The fine-grain zone around the fusion line is the softening zone of the welded joint. For tensile conditions, the cracks were initiated at the softening zone and extended along the fusion line to the final fracture. Under fatigue loading conditions, the weld reinforcement leads to the stress concentration at the weld toe, and at the same time, a lot of pore defects at the weld toe, which causes crack initiation at the pores in the weld toe. Due to the small plastic zone at the fatigue crack tip, the crack propagates almost perpendicular to the loading direction in the heat-affected zone, driven by a mode I crack. A large number of gas pores in the weld zone have no substantial effect on fatigue crack propagation.

Quality Control of Tofu Production Processes Using the Seven Tools Method

Tofu is a food derived from soybeans which is then fermented to extract its juice. The problem that often occurs in the tofu industry is that the products produced still have a lot of defects. The purpose of this research is to identify the types of defects in tofu production and the causes of defects in tofu products and to improve product quality. The method used in this study is the seven tools method. Seven tools are 7 (seven) basic tools used to solve problems in production. The results of the research in the production process of SB tofu occurred 4 types of defects, namely defects in unequal size, defects in terms of texture, defects mixed with dirt and defects in color. The most dominant type of tofu SB defect is the type of size defect that is not the same with a percentage of 45.6%. This type of defect is caused by human, machine, material, method, and environmental factors.

Photocarrier relaxation and saturable absorption in defect-rich, direct chemical vapor deposition-grown graphene glass

Direct growth of large-area uniform graphene films on insulating materials could facilitate the applications of graphene in optoelectronic devices. The ultrafast photocarrier relaxation and saturable absorption of direct chemical vapor deposition-grown graphene glasses, with lots of defects, are studied by using femtosecond time-resolved pump–probe and Z-scan techniques at 800 nm. We find that both the relaxation times associated with hot carrier cooling and the hot phonon effect are greatly suppressed in these defect-rich graphene glasses, which further leads to the increase of both saturation intensity and anisotropy in transient optical response for graphene glasses as compared with defect-free graphene. And, both the suppression effect and saturation intensity increase with the thickness of graphene film. The dominance of defect-assisted carrier-acoustic phonon scattering (i.e., supercollision, the collision of a carrier with both an acoustic phonon and defects) in the cooling process of hot carriers is responsible for the suppression of relaxation time.

Quality Control on Bogo Helmet Coating Process Using the Six Sigma Method, Fault Tree Analysis (FTA) and Failure Mode and Effect Analysis (FMEA)

Hanesda Assembling Helmet is a private company engaged in the assembly of bogo helmets. One of the serious problems faced by this company is that the defective products produced in the production process reach 4% of the tolerance limit set by the company, which is 1.5%. The purpose of this research is to control the quality of the coating process which has a lot of product defects. The method used in this study is the Six Sigma method with the stages of DMAIC. The method used to analyze the causes of failure is the FTA method and the method used to determine the weighting in prioritizing the repair design is the FMEA method. The results of the research using the Six Sigma method are obtained DPMO values of 19,931 with a Sigma level of 3.57. Types of defects that have the highest RPN are streak defects, flex defects, uneven paint defects and paint runs defects with an RPN value of 112. High RPN value will be prioritized for improvement plans.

One-step controlled synthesis of ZnO-ZnSe hollow nanospheres with surface defects for selective detection of NO2

The introduction of surface defects in sensing materials is an important means to improve sensor performance. In this work, we design a simple one-step route to synthesize ZnO-ZnSe without any template or surfactant, and obtain ZnO-ZnSe hollow spherical composite with a diameter of ∼ 200 nm. The shell of the hollow spheres is assembled by nanoparticles with a lot of surface defects after sintering at 800 °C in N2 atmosphere. The surface defects can promote the sensing materials release more electrons and facilitate the reaction of oxygen ions on the material surface. It is beneficial to the adsorption of NO2 on sensing materials for enhancing the sensing performance. The composite shows excellent sensitivity for 10 ppm NO2 at 170 °C, which is 5.32 times that of pure ZnO. And the sensor can recover quickly within 28 s after responding to NO2. It is also satisfactory for the sensor to detect the lowest concentration of 100 ppb. The chemical characterizations such as DRS, PL, XPS, GC–MS, and Kelvin probe are used, combined with the calculation of DFT theory to further explore the synergy effect of the formation of ZnO and ZnSe heterojunction and the surface defects caused by high-temperature sintering on the improvement of sensor performance.