In this paper, Firstly, a three-dimensional TSV chip vertical stacking package structure finite element analysis model was established based on ANSYS software, and the model was subjected to finite element analysis under thermal cyclic loading conditions to obtain the stress-strain distribution of TSV interconnect structure; and orthogonal test design and ANOVA were performed on the TSV interconnect structure parameters and material parameters under thermal cyclic loading. The results show that the copper column diameter, copper column height and SiO 2 layer thickness have significant effects on the stress of the TSV interconnect structure at the confidence level of 95%. Then the BP neural network prediction software was established to realize the stress prediction of TSV interconnect structure under thermal cyclic loading, and the neural network was tested by five different sets of TSV interconnect structure morphological parameters combinations, and the predicted and simulated values were evaluated with an error of x%, indicating that it can better realize the stress prediction of TSV interconnect structure under thermal cyclic loading.
In this paper, a three-dimensional finite model of a 100-PIN QFP package solder joint package is established using ANSYS software. The QFP model is loaded with bending stress conditions at a constant temperature field of 125°C for 600 seconds, and finite element simulation analysis is performed to explore the solder joint reliability according to the static storage package. In order to analyze the effects of different levels of PCB thickness, chip thickness, solder joint height and solder joint spacing on the solder joint stress, nine sets of orthogonal experiments with 4 factors and 3 levels are designed in this paper, and the corresponding nine sets of finite element models are built based on the orthogonal experimental groups for stress analysis. Then the experimental data were visualized by extreme difference analysis and one-way ANOVA was performed by SPSS software to obtain the optimal combination and verify the correctness of the combination. The results show that under the condition of bending stress loaded on QPF solder joints at a constant temperature of 125°C for 600 seconds, the stress distribution in the solder joints is not uniform and the maximum stress appears on the outermost side of the solder joints, near the side where the applied load touches the surface of the PCB. The optimal combination of parameters is 0.8mm PCB thickness, 1.2mm chip thickness, 0.08mm solder joint height and 0.5mm solder joint spacing, under which the maximum bending stress of QPF solder joint is significantly reduced.
Reversible protein ubiquitination plays essential roles in regulating cellular processes. Although many reports have described the functions of ubiquitination in plant defense responses, few have focused on global changes in the ubiquitome. To better understand the regulatory roles of ubiquitination in rice pattern-triggered immunity (PTI), we investigated the ubiquitome of rice seedlings after treatment with two pathogen-associated molecular patterns, the fungal-derived chitin or the bacterial-derived flg22, using label-free quantitative proteomics. In chitin-treated samples, 144 and 167 lysine-ubiquitination sites in 121 and 162 proteins showed increased and decreased ubiquitination, respectively. In flg22-treated samples, 151 and 179 lysine-ubiquitination sites in 118 and 166 proteins showed increased and decreased ubiquitination, respectively. Bioinformatic analyses indicated diverse regulatory roles of these proteins. The ubiquitination levels of many proteins involved in the ubiquitination system, protein transportation, ligand recognition, membrane trafficking, and redox reactions were significantly changed in response to the elicitor treatments. Notably, the ubiquitination levels of many enzymes in the phenylpropanoid metabolic pathway were up-regulated, indicating that this pathway is tightly regulated by ubiquitination during rice PTI. Additionally, the ubiquitination levels of some key components in plant hormone signaling pathways were up- or down-regulated, suggesting that ubiquitination may fine-tune hormone pathways for defense responses. Our results demonstrated that ubiquitination, by targeting a wide range of proteins for degradation or stabilization, has a widespread role in modulating PTI in rice. The large pool of ubiquitination targets will serve as a valuable resource for understanding how the ubiquitination system regulates defense responses to pathogen attack.
In this paper, we mainly focus on SOP solder joints as the research target, and use Ansys Workbench software to establish a finite element analysis model of SOP chips, using solder joint length, solder joint width, and solder joint height as design variables to perform finite element analysis of the modeled solder joints under the loading conditions of random vibration. Using the maximum stress and maximum strain of SOP solder joints as the target values, a three-factor, three-level experiment was established using Design-Expert software to analyze the stress-strain distribution of SOP solder joints under random vibration conditions, and the parameters were optimized using the response surface method and simulated. The results show that under the condition of random vibration, the maximum stress and maximum strain of SOP solder joints appear at the farthest distance from the center of the chip where the solder joints are bonded to the PCB, indicating that failure is most likely to occur at this location, and based on the response surface optimization method, the optimal combination of geometric parameters for solder joint length 0.85 mm, solder joint width 0.44 mm, and solder joint height 0.07 mm is obtained, and the optimal combination of solder joints Simulation analysis is performed to verify the optimal combination of solder joints. The results show that the maximum stress and maximum strain in the solder joints are reduced, which verifies the correctness of the optimization results.
Objective
To explore 3D constructive interference insteady state sequence value of related diseases in trigeminal neuralgia.
Methods
A retrospective analysis of 62 cases of trigeminal neuralgia as the main symptoms of patients with brain magnetic resonance imaging (MRI) routine scan and 3D constructive interference insteady state (3D-CISS) sequence images, of which 12 cases were enhanced scan, comparative analysis of MRI 3D-CISS sequence and conventional sequence of trigeminal nerve. The lesion showed the condition and was compared with the outcome of the operation. Trigeminal neuralgia-related lesions mainly included the trigeminal nerve brain pool around the vascular compression or transition, solid tumors and tumor-like lesions.
Results
Preoperative MRI 3D-CISS sequence was used to diagnose the vascular compression or metastasis of the trigeminal nerve pool segment in 46 cases. Forty-five patients were found to be responsible blood vessels. The 3D-CISS sequence showed 95.83% coincidence with surgical exploration. The routine sequence could not show the trigeminal The brain around the brain was forced or pushed. 3D-CISS sequence showed eight cases of solid tumors, routine scan showed six cases of solid tumors. Tumor-like lesions were shown in 6 cases of MRI3D-CISS sequences and routine plain scan sequences. The sensitivity of 3D-CISS sequence to trigeminal neuralgia-related disease was 96.77%, and the sensitivity of MRI routine scan to trigeminal neuralgia was only 19.35%. There was significant difference in the sensitivity of 3D-CISS sequence and conventional plain scan sequence to trigeminal neuralgia-related diseases (P<0.01).
Conclusions
MRI 3D-CISS sequence has a significant advantage in trigeminal neuralgia-related disease, and patients with trigeminal neuralgia should routinely use 3D-CISS sequences.
Key words:
Magnetic resonance imaging; Trigeminal neuralgia/CO/DI
Based on ANSYS simulation software, a finite element model of BGA stacked solder joints was established. In order to analyze the effects of solder joint height and diameter and chip thickness on the thermal stress of solder joints under power cycling load, 17 sets of tests with 3-factor and 3-level parameter combinations were designed using the response surface method, and the regression equation of solder joint stress with these 3 factors was established. A genetic algorithm based regression equation was used to find the optimal combination of parameter levels for the stacked solder joint package structure and verified the correctness. The results show that: the thermal stress distribution of the stacked solder joints under power cycling load is not uniform, the key solder joints are in the four corner solder joints, and the maximum stress is in the contact area between the solder joints and the chip; by the genetic algorithm to find the best, the structural parameters of the lowest stress level combination of the stacked solder joints are: solder joint height 0.355mm, solder joint diameter 0.464mm, chip thickness 0.835mm; It is also verified through simulation that the optimal level combination of the structural parameters of the solder joints, the thermal stress of the solder joints is significantly reduced, and the structural optimization of the BGA stacked solder joints is achieved.
The reliability issues of TSV interconnect structures directly affect the performance of packaged devices. The reliability of TSV interconnected structures under high temperature and random vibration conditions is investigated, and the effect of changes in the parameters about the TSV structure on its reliability is studied. Five factors of TSV copper column diameter, TSV copper column height, TSV spacing, bump height and bump diameter were selected, and three level values were set under each factor to obtain 18 sets of test TSV parameter structure combinations for this experiment through orthogonal tests, and a finite element analysis model of the relevant size TSV interconnection structure was established to study the effects of the five influencing factors on the stress-strain of the TSV interconnection structure under high temperature and random vibration loading conditions at 125°C. The experimental results obtained. By studying the graph of the stress-strain distribution law of the TSV interconnection structure, the analysis shows that the stress at the top of the copper column of the TSV interconnection structure is greater than the rest under the coupled loading conditions of 125°C high temperature and random vibration. At the same time, after conducting a polar variance ANOVA on the experimental data to analyze the degree of influence as well as the significance, the gray correlation affecting the TSV interconnection structure was obtained, and the results showed that the TSV spacing affected the stress-strain of the TSV interconnection structure the most, followed by the TSV copper column diameter and bump diameter, and finally the TSV copper column height and bump height. This test provides the basis for future analysis of the effects of TSV packaging under coupled loading conditions of high temperature and random vibration, accelerating the development of the electronics packaging industry.
The formation and reliability of solder joints is the key to chip bonding technology, so the study of new types of solder joints is always a popular research topic in the field of electronic packaging. In this paper, a three-dimensional finite element analysis model is established for a new type of solder joints (laminated solder joints). Firstly, through the Taguchi method of experimental design, the effects of solder joints diameter, height, pitch and pad diameter on the stress-strain of the laminated solder joints under random vibration load are analyzed using the signal-to-noise ratio, and then the structural parameters of the solder joints are optimized by combining gray correlation analysis on the stress-strain of the laminated solder joints under random vibration load. The results show that the laminated solder joints are prone to stress concentrations at both ends of the solder joints and that the stress strain on the side of the contact surface with the PCB is greater than the stress strain on the side of the contact surface with the chip. Stress-strain clouds show that the stress-strain in the laminated solder joints gradually increases from the inside to the outside, with the highest stress-strain in the corners of the outer perimeter. The signal-to-noise analysis shows that the height of the weld joints has the greatest influence on the stress-strain of the laminated weld joints. 3.37% reduction in stress and 3.62% reduction in strain, the stress-strain values of the stacked solder joints were improved and the reliability of Taguchi and the grey correlation method was verified.
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