A Study on the Reliability Evaluation of a 3D Packaging Storage Module under Temperature Cycling Ultimate Stress Conditions.

Based on the theory of reliability enhancement testing technology, this study used a variety of testing combinations and finite element simulations to analyze the stress-strain properties of 3D packaging storage modules and then evaluated its operating and destruction limits during temperature cycling tests (-65 °C~+150 °C) for the purpose of identifying the weak points and failure mechanisms affecting its reliability. As a result of temperature cycling ultimate stress, 3D packaging storage devices can suffer from thermal fatigue failure in the case of abrupt temperature changes. The cracks caused by the accumulation of plastic and creep strains can be considered the main factors. Crack formation is accelerated by the CTE difference between the epoxy resin and solder joints. Moreover, the finite element simulation results were essentially the same as the testing results, with a deviation occurring within 10%.

IC Packaging Material Identification via a Hybrid Deep Learning Framework with CNN-Transformer Bidirectional Interaction.

With the advancement of micro- and nanomanufacturing technologies, electronic components and chips are increasingly being miniaturized. To automatically identify their packaging materials for ensuring the reliability of ICs, a hybrid deep learning framework termed as CNN-transformer interaction (CTI) model is designed on IC packaging images in this paper, in which several cascaded CTI blocks are designed to bidirectionally capture local and global features from the IC packaging image. Each CTI block involves a CNN branch with two designed convolutional neural networks (CNNs) for CNN local features and a transformer branch with two transformers for transformer global features and transformer local-window features. A bidirectional interaction mechanism is designed to interactively transfer the features in channel and spatial dimensions between the CNNs and transformers. Experimental results indicate that the hybrid framework can recognize three types of IC packaging materials with a good performance of 96.16% F1-score and 97.92% accuracy, which is superior to some existing deep learning methods.

SCAN: sequence-based context-aware association network for hepatic vessel segmentation.

Accurate segmentation of hepatic vessel is significant for the surgeons to design the preoperative planning of liver surgery. In this paper, a sequence-based context-aware association network (SCAN) is designed for hepatic vessel segmentation, in which three schemes are incorporated to simultaneously extract the 2D features of hepatic vessels and capture the correlations between adjacent CT slices. The two schemes of slice-level attention module and graph association module are designed to bridge feature gaps between the encoder and the decoder in the low- and high-dimensional spaces. The region-edge constrained loss is designed to well optimize the proposed SCAN, which integrates cross-entropy loss, dice loss, and edge-constrained loss. Experimental results indicate that the proposed SCAN is superior to several existing deep learning frameworks, in terms of 0.845 DSC, 0.856 precision, 0.866 sensitivity, and 0.861 F1-score.

A High-Precision Multi-Beam Optical Measurement Method for Cylindrical Surface Profile.

To automatically measure the surface profile of a cylindrical workpiece, a high-precision multi-beam optical method is proposed in this paper. First, some successive images for the cylindrical workpiece's surface are acquired by a multi-beam angle sensor under different light directions. Then, the light directions are estimated based on the feature regions in the images to calculate surface normal vectors. Finally, according to the relationship of the surface normal vector and the vertical section of the workpiece's surface, a depth map is reconstructed to achieve the curvature surface, which can be employed to measure the curvature radius of the cylindrical workpiece's surface. Experimental results indicate that the proposed measurement method can achieve good measurement precision with a mean error of the curvature radius of a workpiece's surface of 0.89% at a reasonable speed of 10.226 s, which is superior to some existing methods.

ATNet: A Defect Detection Framework for X-ray Images of DIP Chip Lead Bonding.

In order to improve the production quality and qualification rate of chips, X-ray nondestructive imaging technology has been widely used in the detection of chip defects, which represents an important part of the quality inspection of products after packaging. However, the current traditional defect detection algorithm cannot meet the demands of high accuracy, fast speed, and real-time chip defect detection in industrial production. Therefore, this paper proposes a new multi-scale feature fusion module (ATSPPF) based on convolutional neural networks, which can more fully extract semantic information at different scales. In addition, based on this module, we design a deep learning model (ATNet) for detecting lead defects in chips. The experimental results show that at 8.2 giga floating point operations (GFLOPs) and 146 frames per second (FPS), mAP0.5 and mAP0.5-0.95 can achieve an average accuracy of 99.4% and 69.3%, respectively, while the detection speed is faster than the baseline yolov5s by nearly 50%.

Multi-task banded regression model: A novel individual survival analysis model for breast cancer.

PURPOSE: To reveal the hazard probability of individual breast cancer patients, a multi-task banded regression model is proposed for individual survival analysis of breast cancer. METHODS: A banded verification matrix is designed to construct the response transform function of the proposed multi-task banded regression model, which can solve the repeated switching of survival rate. A martingale process is introduced to construct different nonlinear regressions for different survival subintervals. The concordance index (C-index) is used to compare the proposed model with Cox proportional hazards (CoxPH) models and previous multi-task regression models. RESULTS: Two commonly-used breast cancer datasets are employed to validate the proposed model. Specifically, the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) includes 1981 breast cancer patients, of which 57.7% died of breast cancer. The Rotterdam & German Breast Cancer Study Group (GBSG) includes 1546 patients with lymph node-positive breast cancer in a randomized clinical trial, of which 44.4% died. Experimental results indicate that the proposed model is superior to some existing models for overall and individual survival analysis of breast cancer, with the C-index of 0.6786 for the GBSG and 0.6701 for the METABRIC. CONCLUSION: The superiority of the proposed model can be contributed to three novel ideas. One is that a banded verification matrix can band the response of the survival process. Second, the martingale process can construct different nonlinear regressions for different survival subintervals. Third, the novel loss can adapt the model to making the multi-task regression similar to the real survival process.

A Lightweight Method for Detecting IC Wire Bonding Defects in X-ray Images.

Integrated circuit (IC) X-ray wire bonding image inspections are crucial for ensuring the quality of packaged products. However, detecting defects in IC chips can be challenging due to the slow defect detection speed and the high energy consumption of the available models. In this paper, we propose a new convolutional neural network (CNN)-based framework for detecting wire bonding defects in IC chip images. This framework incorporates a Spatial Convolution Attention (SCA) module to integrate multi-scale features and assign adaptive weights to each feature source. We also designed a lightweight network, called the Light and Mobile Network (LMNet), using the SCA module to enhance the framework's practicality in the industry. The experimental results demonstrate that the LMNet achieves a satisfactory balance between performance and consumption. Specifically, the network achieved a mean average precision (mAP50) of 99.2, with 1.5 giga floating-point operations (GFLOPs) and 108.7 frames per second (FPS), in wire bonding defect detection.

Research on the Mechanism of Multi-Domain Coupling Centrifugal Electrostatic Blowing Flying Deposition.

The centrifugal electrostatic blowing process proposed in this paper solves the difficult continuous and stable deposition problem in the traditional centrifugal electrostatic spinning process. By establishing a flight deposition model of the centrifugal electrostatic spraying process, CFD is used to simulate and analyze the electrohydrodynamic effect of centrifugal jets, and the driving mechanism is explored. Subsequently, MATLAB is used to obtain the optimal solution conditions, and finally, the establishment of a two-dimensional flight trajectory model is completed and experimentally verified. In addition, the deposition model of the jet is established to clarify the flight trajectory under the multi-field coupling, the stable draft area of the jet is found according to this, and the optimal drafting station is clarified. This research provides new ideas and references for the exploration of the deposition mechanism of the centrifugal electrostatic blowing and electrostatic spinning process.

Surface Quality Control Strategy of Aspherical Mold Based on Screw Feed Polishing of Small Polishing Tool.

For small aspherical molds, it is difficult for the existing polishing method to take into account the correction of the surface error and the control of the uniformity of the surface roughness (SR) distribution, because the polishing tool is always larger than the small mold. Therefore, we used viscoelastic polyester fiber cloth to wrap the small steel ball as a polishing tool to adapt to the surface shape change of the aspherical mold, and designed a semi-flexible small polishing disc tool with microstructure, which can better adapt to the curvature change of aspherical surface and obtain better SR Ra. At the same time, a combined polishing method of constant speed and variable speed for screw feed was proposed to improve the uniformity of SR distribution in the paper. Then, a series of theoretical analysis and experimental verification were carried out in this paper to predict the tool influence function (TIF) of the two polishing tools and the effectiveness of the combined polishing method. In the experiment, a TIF bandwidth of about 0.46 mm was obtained with a small spherical polishing tool, which favors the surface shape correction of the small aspherical mold. The experiment of uniform removal with a small polishing disc tool was carried out to quickly reduce the Ra. Finally, the surface quality of the aspherical mold was effectively improved, combined with the constant speed and variable speed polishing modes of screw feed of the small spherical polishing tool and the smoothing effect of the small polishing disc tool. The peak valley (PV) of two small aspherical molds with an optical effective diameter less than 13 mm converged from 0.3572 µm and 0.2075 µm to 0.1282 µm and 0.071 µm, respectively. At the same time, the SR dispersion coefficient was reduced from 27.9% and 41.6% to 14.2% and 12.7%, respectively. The study provides a good solution for the surface quality control of small aspherical molds.

Fabrication of bioinspired grid-crimp micropatterns by melt electrospinning writing for bone-ligament interface study.

Many strategies have been adopted to engineer bone-ligament interface, which is of great value to both the tissue regeneration and the mechanism understanding underlying interface regeneration. However, how to recapitulate the complexity and heterogeneity of the native bone-ligament interface including the structural, cellular and mechanical gradients is still challenging. In this work, a bioinspired grid-crimp micropattern fabricated by melt electrospinning writing (MEW) was proposed to mimic the native structure of bone-ligament interface. The printing strategy of crimped fiber micropattern was developed and the processing parameters were optimized, which were used to mimic the crimp structure of the collagen fibrils in ligament. The guidance effect of the crimp angle and fiber spacing on the orientation of fibroblasts was studied, and both of them showed different levels of cell alignment effect. MEW grid micropatterns with different fiber spacings were fabricated as bone region. Both the alkaline phosphatase activity and calcium mineralization results demonstrated the higher osteoinductive ability of the MEW grid structures, especially for that with smaller fiber spacing. The combined grid-crimp micropatterns were applied for the co-culture of fibroblasts and osteoblasts. The results showed that more cells were observed to migrate into the in-between interface region for the pattern with smaller fiber spacing, suggested the faster migration speed of cells. Finally, a cylindrical triphasic scaffold was successfully generated by rolling the grid-crimp micropatterns up, showing both structural and mechanical similarity to the native bone-ligament interface. In summary, the proposed strategy is reliable to fabricate grid-crimp triphasic micropatterns with controllable structural parameters to mimic the native bone-to-ligament structure, and the generated 3D scaffold shows great potential for the further bone-ligament interface tissue engineering.

Fabrication and in vitro evaluation of PCL/gelatin hierarchical scaffolds based on melt electrospinning writing and solution electrospinning for bone regeneration.

As an emerging 3D printing technique, melt electrospinning writing (MEW) has been used to fabricate scaffolds with controllable structure and good mechanical strength for bone regeneration. However, how to further improve MEW scaffolds with nanoscale extracellular matrix (ECM) mimic structure and bioactivity is still challenging. In this study, we proposed a simple composite process by combining MEW and solution electrospinning (SE) to fabricate a micro/nano hierarchical scaffold for bone tissue engineering. The morphological results confirmed the hierarchical structure with both well-defined MEW microfibrous grid structure and SE random nanofiber morphology. The addition of gelatin nanofibers turned the scaffolds to be hydrophilic, and led to a slight enhancement of mechanical strength. Compared with PCL MEW scaffolds, higher cell adhesion efficiency, improved cell proliferation and higher osteoinductive ability were achieved for the MEW/SE composite scaffolds. Finally, multilayer composite scaffolds were fabricated by alternately stacking of MEW layer and SE layer and used to assess the effect on cell ingrowth in the scaffolds. The results showed that gelatin nanofibers did not inhibit cell penetration, but promoted the three-dimensional growth of bone cells. Thus, the strategy of the combined use of MEW and SE is a potential method to fabricate micro/nano hierarchical scaffolds to improve bone regeneration.

Stimulus-Responsive Shrinkage in Electrospun Membranes: Fundamentals and Control.

Shrinkage is observed in many electrospun membranes. The stretched conformation of the macromolecular chains has been proposed as the possible cause. However, so far, our understanding of the fundamentals is still qualitative and cannot provide much help in the shrinkage control. In this paper, based on the crimped fibers after stimulus-induced shrinkage, a clear evidence of buckling, the gradient pre-strain field in the cross-section of the electrospun fibers, which is the result of a gradient solidification field and a tensile force in the fibers during electrospinning, is identified as the underlying mechanism for the stimulus-induced shrinkage. Subsequently, two buckling conditions are derived. Subsequently, a series of experiments are carried out to reveal the influence of four typical processing parameters (namely, the applied voltage, solution concentration, distance between electrodes, and rotation speed of collector), which are highly relevant to the formation of the gradient pre-strain field. It is concluded that there are some different ways to achieve the required shrinkage ratios in two in-plane directions (i.e., the rotational and transverse directions of the roller collector). Some of the combinations of these parameters are more effective at achieving high uniformity than others. Hence, it is possible to optimize the processing parameters to produce high-quality membranes with well-controlled shrinkage in both in-plane directions.

Wearable Flexible Strain Sensor Based on Three-Dimensional Wavy Laser-Induced Graphene and Silicone Rubber.

Laser-induced graphene (LIG) has the advantages of one-step fabrication, prominent mechanical performance, as well as high conductivity; it acts as the ideal material to fabricate flexible strain sensors. In this study, a wearable flexible strain sensor consisting of three-dimensional (3D) wavy LIG and silicone rubber was reported. With a laser to scan on a polyimide film, 3D wavy LIG could be synthesized on the wavy surface of a mold. The wavy-LIG strain sensor was developed by transferring LIG to silicone rubber substrate and then packaging. For stress concentration, the ultimate strain primarily took place in the troughs of wavy LIG, resulting in higher sensitivity and less damage to LIG during stretching. As a result, the wavy-LIG strain sensor achieved high sensitivity (gauge factor was 37.8 in a range from 0% to 31.8%, better than the planar-LIG sensor), low hysteresis (1.39%) and wide working range (from 0% to 47.7%). The wavy-LIG strain sensor had a stable and rapid dynamic response; its reversibility and repeatability were demonstrated. After 5000 cycles, the signal peak varied by only 2.32%, demonstrating the long-term durability. Besides, its applications in detecting facial skin expansion, muscle movement, and joint movement, were discussed. It is considered a simple, efficient, and low-cost method to fabricate a flexible strain sensor with high sensitivity and structural robustness. Furthermore, the wavy-LIG strain senor can be developed into wearable sensing devices for virtual/augmented reality or electronic skin.

Melt electrohydrodynamic 3D printed poly (ε-caprolactone)/polyethylene glycol/roxithromycin scaffold as a potential anti-infective implant in bone repair.

Implanted scaffold or bone substitute is a common method to treat bone defects. However, the possible bone infection caused by orthopaedic surgery has created a challenging clinical problem and generally invalidate bone repair and regeneration. In this study, a poly (ε-caprolactone) (PCL)/polyethylene glycol (PEG)/roxithromycin (ROX) composite scaffold was prepared via melt electrohydrodynamic (EHD) 3D printing. Fourier transform infrared spectroscopy (FTIR) spectroscopy was performed to verify the existence of PEG and ROX in the scaffolds. By water contact angle measurement, the addition of both PEG and ROX was found to improve the hydrophilicity of the scaffolds. By in vitro drug release assay, the PCL/PEG/ROX scaffolds showed an initial burst drug release and subsequent long-term sustained release behaviour, which is favourable for the prevention and treatment of bone infections. The antibacterial assays against E. coli and S. aureus demonstrated that the composite scaffold with ROX possessed effective antibacterial activity, especially for S. aureus, the main cause of bone infection. The immunostaining and MTT assay with human osteoblast-like cells (MG63) indicated that cells showed good viability and growth on the scaffolds. Therefore, the melt EHD 3D printed PCL/PEG/ROX scaffold could be a promising anti-infective implant for bone tissue engineering.

Investigation of serum amino acids involved in gallic acid detoxification of formaldehyde by liquid chromatography/tandem mass spectrometry and neutral loss scan.

RATIONALE: Gallic acid is one of the most common polyphenols in natural products and human diet. The consumption of gallic acid reduces the incidence of cardiovascular diseases, chronic metabolic disorders and cancers. Most previous publications focused on the antioxidative or prooxidative properties of gallic acid. In the present work, gallic acid as a trapping agent of blood formaldehyde was investigated by liquid chromatography/tandem mass spectrometry (LC/MS/MS) and neutral loss scan. METHODS: Serum samples incubated with gallic acid were subjected to LC/MS/MS analysis using an LTQ XL ion trap mass spectrometer. The adduct ions of gallic acid-formaldehyde-amino acids were explored by investigation of their fragmentation patterns and neutral loss scan experiments. RESULTS: A series of Mannich adducts (namely, gallic acid-formaldehyde-alanine, gallic acid-formaldehyde-proline, gallic acid-formaldehyde-leucine or gallic acid-formaldehyde-isoleucine and gallic acid-formaldehyde-phenylalanine) were identified as metabolites by neutral loss scan experiments. CONCLUSIONS: This work demonstrated that serum amino acids are involved in gallic acid detoxification of formaldehyde. Because excessive formaldehyde in blood is implicated in a variety of disease pathologies, detoxification of formaldehyde, especially endogenous formaldehyde, may be another health beneficial effect of gallic acid. It also suggested that more attention should be paid to Mannich-type metabolites of polyphenol-formaldehyde-amino acids in research into the pharmacokinetics and bioavailability of polyphenols.

Dual-wavelength intensity-modulated Fabry-Perot refractive index sensor driven by temperature fluctuation.

A refractive index sensor based on an in-line Fabry-Perot interferometer is proposed and experimentally demonstrated. Two lasers are combined and injected into the sensor head. The power responses of two wavelengths are measured by a dual-channel optical power meter simultaneously. The two reflected power signals distribute along an ellipse. The refractive index of the liquid is calculated from the half length of the longer axes of the fitted ellipse. The refractive index sensing system is demonstrated to measure the refractive index of the salt solutions with different concentrations. The demodulated results matched well with the refractive index measured by the Abbe refractometer, and a resolution of 0.0017 was obtained. Since the temperature is eliminated during the ellipse fitting, the measuring result is insensitive to the temperature fluctuation. The proposed refractive index sensing sensor has outstanding advantages, such as low demodulation cost, simple fabrication, easy cleaning, and good mechanical strength, and will be of importance in biological detection, chemical analysis, and water pollution monitoring.

Multiplexing of anti-resonant reflecting optical waveguides for temperature sensing based on quartz capillary.

A novel multiplexing scheme of anti-resonant reflecting optical waveguides (ARROW) for temperature sensing based on quartz capillary is firstly proposed and experimentally demonstrated. Each ARROW-based sensor is manufactured by fusion splicing a short section of capillary between two standard single-mode fiber (SMF). Experiments were demonstrated on a three cascaded ARROW-based sensing network chopped from a fiber array with multiple sensors. Simulation and experimental results demonstrate that the positions of sharp periodic transmission dips are independent of the capillary length, but dependent on the refractive indexes and thickness of the silica cladding. The temperature sensitivities of 18.77 pm/°C, 18.19 pm/°C, and 17.94 pm/°C are achieved by wavelength demodulation of selected dips of Gaussian fitting algorithm, and the tunability of sensitivity can be realized by selecting different dips. Furthermore, the merits of low strain cross-sensitivity (-0.71 pm/µÎµ), easy fabrication capability and high spectral extinction ratio (about 30dB) make the proposed multiplexing scheme an excellent candidate for performing multi-point and multi-parameter measurements in harsh environments.

A furoviral replicase recruits host HSP70 to membranes for viral RNA replication.

Many host factors have been identified to be involved in viral infection. However, although furoviruses cause important diseases of cereals worldwide, no host factors have yet been identified that interact with furoviral genes or participate in the viral infection cycle. In this study, both TaHSP70 and NbHSP70 were up-regulated in Chinese wheat mosaic furovirus (CWMV)-infected plants. Their overexpression and inhibition were correlated with the accumulation of viral genomic RNAs, suggesting that the HSP70 genes could be necessary for CWMV infection. The subcellular distributions of TaHSP70 and NbHSP70 were significantly affected by CWMV infection or by infiltration of RNA1 alone. Further assays showed that the viral replicase encoded by CWMV RNA1 interacts with both TaHSP70 and NbHSP70 in vivo and vitro and that its region aa167-333 was responsible for the interaction. Subcellular assays showed that the viral replicase could recruit both TaHSP70 and NbHSP70 from the cytoplasm or nucleus to the granular aggregations or inclusion-like structures on the intracellular membrane system, suggesting that both HSP70s may be recruited into the viral replication complex (VRC) to promote furoviral replication. This is the first host factor identified to be involved in furoviral infection, which extends the list and functional scope of HSP70 chaperones.

Identification and characterization of microsatellite markers in Pinus kesiya var. langbianensis (Pinaceae).

PREMISE OF THE STUDY: Microsatellite primers were developed in Pinus kesiya var. langbianensis (Pinaceae), a species native to southwestern China, to investigate its genetic diversity and population structure in order to provide information for the conservation and management of this species. METHODS AND RESULTS: Using next-generation sequencing, a total of 2349 putative simple sequence repeat primer pairs were designed. Eighteen polymorphic markers in 60 individuals belonging to four populations of P. kesiya var. langbianensis were identified and characterized with two to 11 alleles per locus. The observed and expected heterozygosity ranged from 0.000 to 0.800 and 0.000 to 0.840, respectively. Each of these loci cross-amplified in the closely related species P. massoniana, P. densata, P. tabuliformis, and P. yunnanensis, with one to seven alleles per locus. CONCLUSIONS: The new markers are promising tools to study the population genetics of P. kesiya var. langbianensis and related species.

Interaction between southern rice black-streaked dwarf virus minor core protein P8 and a rice zinc finger transcription factor.

The fijivirus southern rice black-streaked dwarf virus (SRBSDV) causes one of the most serious viral diseases of rice in China and Vietnam. To better understand the molecular basis of SRBSDV infection, a yeast two-hybrid screen of a rice cDNA library was carried out using P8, a minor core protein of SRBSDV, as the bait. A rice Cys2His2-type zinc finger protein (OsZFP) was found to interact with SRBSDV P8. A strong interaction between SRBSDV P8 and OsZFP was then confirmed by pull-down assays, and bimolecular fluorescence complementation assays showed that the in vivo interaction was specifically localized in the nucleus of plant cells. Using a series of deletion mutants, it was shown that both the NTP-binding region of P8 and the first two zinc fingers of OsZFP were crucial for their interaction in plant cells. The localization in the nucleus and activation of transcription in yeast supports the notion that OsZFP is a transcription factor. SRBSDV P8 may play an important role in fijiviral infection and symptom development by interfering with the host transcription activity of OsZFP.