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A meta-analysis was performed to analyze the association between PD-L1 expression and overall survival (OS) in various tumors and to identify potential targets through biological information analysis.the data were collected from PubMed and Cochrane library, the all analysis of our study were conducted by STATA software and online website.Ten articles (including 11 studies) that met all inclusion criteria were obtained. The combined HR showed that high PD-L1 expression was significantly associated with poor overall survival (HR = 1.84, 95% CI: 1.15-2.93). Pathway analysis revealed that the upregulated genes were primarily involed in biological processes, including nucleic acid transcription, biosynthesis and negative regulation of cell metabolism. The downregulated genes were primarily involed in the regulation of cell cycle, including chromosome separation and DNA metabolism. The top ten genes that were identified were hub genes (CDK1, CCNB1, CCNA2, KIF11, CDC20, UBE2C, NCAPG, AURKA, AURKB, CHEK1), which had significant function in cell differentiation and virus infection. The Kaplan-Meier survival curve indicated that CCNB1, KIF11, UBE2C, NCAPG, AURKA and CHEK1 were statistically significant (P0.05).PD-L1 was found to be a latent biomarker for predicting the prognostic value of cancer and also a therapeutic target.

Existing solutions to zero-shot text classification either conduct prompting with pre-trained language models, which is sensitive to the choices of templates, or rely on large-scale annotated data of relevant tasks for meta-tuning. In this work, we propose a new paradigm based on self-supervised learning to solve zero-shot text classification tasks by tuning the language models with unlabeled data, called self-supervised tuning. By exploring the inherent structure of free texts, we propose a new learning objective called first sentence prediction to bridge the gap between unlabeled data and text classification tasks. After tuning the model to learn to predict the first sentence in a paragraph based on the rest, the model is able to conduct zero-shot inference on unseen tasks such as topic classification and sentiment analysis. Experimental results show that our model outperforms the state-of-the-art baselines on 7 out of 10 tasks. Moreover, the analysis reveals that our model is less sensitive to the prompt design. Our code and pre-trained models are publicly available at https://github.com/DAMO-NLP-SG/SSTuning ., Accepted to the Findings of ACL 2023

Cross-lingual topic models have been prevalent for cross-lingual text analysis by revealing aligned latent topics. However, most existing methods suffer from producing repetitive topics that hinder further analysis and performance decline caused by low-coverage dictionaries. In this paper, we propose the Cross-lingual Topic Modeling with Mutual Information (InfoCTM). Instead of the direct alignment in previous work, we propose a topic alignment with mutual information method. This works as a regularization to properly align topics and prevent degenerate topic representations of words, which mitigates the repetitive topic issue. To address the low-coverage dictionary issue, we further propose a cross-lingual vocabulary linking method that finds more linked cross-lingual words for topic alignment beyond the translations of a given dictionary. Extensive experiments on English, Chinese, and Japanese datasets demonstrate that our method outperforms state-of-the-art baselines, producing more coherent, diverse, and well-aligned topics and showing better transferability for cross-lingual classification tasks., Accepted to AAAI2023 conference

Pediatric ambulatory surgery can minimize the separation of pediatric patients from their parents, relieve anxiety, and offer care at a reduced cost. However, children are prone to experiencing pain, nausea, vomiting, delirium, and other complications after anesthesia and ambulatory surgery due to their anatomical and physiological characteristics. So, standardized postoperative management is critical to ensure the safety of children and improve the medical quality of pediatric ambulatory surgery. This article reviews new progress in research on common postoperative complications and discharge criteria of pediatric ambulatory surgery.

As an emerging thing different from traditional agriculture, the pastoral complex covers a wide range. This paper mainly designs the agricultural landscape under the concept of the pastoral complex to create a more attractive park, attract more tourists to travel and consume here, develop the local economy, improve local income, and promote the implementation of the rural revitalization strategy in the local area. This paper combines theory with practice, broadens the application methods and theoretical framework of the design of rural complexes, has specific reference value for the research of the design of rural complexes, is conducive to the construction of rural landscapes and the protection of rural ecology, arouses people’s re-examination of the construction of rural landscape, and has specific theoretical and practical significance for the development of rural landscape and the implementation of rural revitalization strategy.

Generally, the vortex structures should be independent of the observers who are moving, especially when their coordinates are non-inertial, which may result in confusions in communications between researchers. The property that not being influenced by the choice of coordinate is called objective. Mostly, researchers would like to gather data in the inertial coordinate because most physical laws are valid in the inertial coordinate. As a result, how to transfer the observations in a non-inertial coordinate to those in an inertial coordinate raises interest. In this paper, methods are provided to obtain velocity and velocity gradient tensor in an inertial coordinate from the non-inertial observations based on one known zero-vorticity point which can be chosen from physical fact such as the point is located in the inviscid region.Further, objective vortex structure can be calculated from the objective velocity or velocity gradient tensor. With Liutex chosen as the indicator of the vortex, two numerical examples are used to test the proposed methods. The results show that the methods perform very well and the relative error is extremely small., Comment: 19 pages, 10 figures, 3 tables

Ovarian cancer is one of the three major gynecologic cancers in the world. The aim of this study is to find the relationship between ovarian cancer and diabetes mellitus by using the genetic screening technique. By GEO database query and related online tools of analysis, we analyzed 185 cases of ovarian cancer and 10 control samples from GSE26712, and a total of 379 different genes were identified, including 104 up-regulated genes and 275 down-regulated genes. The up-regulated genes were mainly enriched in biological processes, including cell adhesion, transcription of nucleic acid and biosynthesis, and negative regulation of cell metabolism. The down-regulated genes were enriched in cell proliferation, migration, angiogenesis and macromolecular metabolism. Protein-protein interaction was analyzed by network diagram and module synthesis analysis. The top ten hub genes (CDC20, H2AFX, ENO1, ACTB, ISG15, KAT2B, HNRNPD, YWHAE, GJA1 and CAV1) were identified, which play important roles in critical signaling pathways that regulate the process of oxidation-reduction reaction and carboxylic acid metabolism. CTD analysis showed that the hub genes were involved in 1,128 distinct diseases (bonferroni-corrected P

Experimental teaching is an important part of college education, especially in engineering colleges. The process management of experimental teaching and the statistic analysis of the laboratory data are complicated and time-consuming. To solve the above problem, this paper develops an interactive laboratory information management system by utilizing emerging technologies such as big data, cloud computing and the Internet of Things. Based on the rich experience of experimental teaching and management of our National Experimental Teaching Demonstration Center, the system is designed to incorporate four functional modules. They are experimental teaching management, experimental equipment management, laboratory open management, communication and interactive management, respectively. Two years of practical operation shows that the system broadens the time and space of the experiment, improves the resource utilization and openness of the laboratory, standardizes the laboratory daily management, provides a good interactive platform for teachers and students, and most important of all, facilitates the statistic analysis of kinds of data. The interactive laboratory information management system adequately explores the functions of the laboratory and significantly improves laboratory operation efficiency.

As widely recognized, vortex represents flow rotation. Vortex should have a local rotation axis as its direction and angular speed as its strength. Vorticity vector has been considered the rotation axis, and vorticity magnitude the rotational strength for a long time in classical fluid kinematics. However, this concept cannot stand in viscous flow. This study demonstrates by rigorous mathematical proof that the vorticity vector is not the fluid rotation axis, and vorticity is not the rotation strength. On the other hand, the Liutex vector is mathematically proved as the fluid rotation axis, and the Liutex magnitude is twice the fluid angular speed., 16 pages and three figures

Additional file 1: Supplementary Figure S1. (A) Immunofluorescence staining was performed to verify the successful construction of PTK6 knockdown CRC cells. The scale bar represents 5 μm. (B) Representative flow cytometery images show the influence of PTK6 on the apoptosis of CRC cells. (C) Representative flow cytometery images demonstrate the effects of PTK6 on the cell cycle progression of CRC cells. (D) Cell viability analyses were performed in PTK6 silencing CRC cells after 5-FU and L-OHP treatment (mean ± SD, n = 3). Supplementary Figure S2. (A) The GSEA results indicate the enrichment of gene sets related to chemoresistance pathways in PTK6 overexpression CRC tissues from GSE73360. (B) The correlations of PTK6 with chemoresistance related genes were detected from TCGA database. (C) The in vitro limiting dilution assay shows the effects of PTK6 on the formation of CSC spheres. (mean ± SD, n = 12), likelihood ratio test. (D) Tumor sphere formation assays indicate that silencing of PTK6 decreases the sphere formation of CSC cells. Scale bar represents 100μm. The right panel shows the relative fold change of sphere number. (mean ± SD, n = 3) (E) Real-time q-PCR results demonstrate a reduced expression of chemoresistance related genes in PTK6 silencing CRC cells. (mean ± SD, n = 3) (F-G) Representative flow cytometery images show the distribution of the CD133+ and SOX2+ cells in control and PTK6 silencing CRC cells. (mean ± SD, n = 3). *P< 0.05, **P < 0.01, ***P < 0.001. Supplementary Figure S3. (A) Tumor sphere formation assays show the representative spheres formed by vector, WT, PTK6-KM and PTK6-YF overexpression CRC cells. Scale bar represents 50 μm. (B) Real-time qPCR results show the expression of stem cell markers in vector, WT, PTK6-KM and PTK6-YF overexpression CRC cells. (mean ± SD, n = 3) (C) Representative flow cytometery images show the distribution of the CD133+ and SOX2+ cells in vector, WT, PTK6-KM and PTK6-YF overexpression CRC cells. Supplementary Figure S4. (A) The correlations between the expression of STAT3 and stemness related genes were detected using the GEO database. (B) Kaplan-Meier curves of overall survival in CRC patients from Nanfang cohort were evaluated based on the expression of p-JAK2 and p-STAT3. The H-score was used as the cut-off to distinguish high and low protein expression. Supplementary Figure S5. (A) Western blot assays show the influence of XMU-MP-2 on the activation of JAK2/STAT3 pathway and the expression of stem cell markers. (B) The influence of XMU-MP-2 on the viability of CRC cells. (C) Clone formation assays show the influence of XMU-MP-2 on CRC cell proliferation in vector, WT, PTK6-KM and PTK6-YF overexpression CRC cells. (D) Representative flow cytometery images show the distribution of the CD133+ cells in vector, WT, PTK6-KM and PTK6-YF overexpression CRC cells. Supplementary Figure S6. (A) IHC staining of the subcutaneous tumors indicates that XMU-MP-2 can inhibit the PTK6 induced activation of JAK2/STAT3 signaling and the expression of stem cell markers. (B) Representative immunohistochemical (IHC) staining images of CRC tissues from the Nanfang cohort show a positive correlation between the expression of PTK6 and stem cell markers. (C) XMU-MP-2 suppresses the weight and volume of the subcutaneous tumors in the L-OHP treated tumor-bearing mice. Both the volume and weight of subcutaneous tumor were shown in the right panel (mean ± SD, n = 3). (D) IHC staining indicates that XMU-MP-2 can reduce the Ki67 index of control and L-OHP treated subcutaneous tumors.(E) XMU-MP-2 suppresses the weight and volume of the PDX tumors derived from CASE 2 in the L-OHP treated tumor-bearing mice. Both the volume and weight of subcutaneous tumor were shown in the right panel (mean ± SD, n = 3). (F) IHC staining indicates that XMU-MP-2 can reduce the phosphorylation of PTK6 and the stem cell markers in the PDX tumors derived from CASE2. Supplementary Table S1. RT-qPCR primer sequences for human genes.

Additional file 2. Forest plot of the plasma levels of LDL-C (a), TC (b) and TG (c) for patients with RA and control group in before -after studies.

Additional file 4. Stratified analyses on the level of high-density lipoprotein in RA.

Additional file 3. Stratified analyses on the level of cholesterol efflux capacity in RA.

Additional file 9. GRADE assessment of the systematic review and meta-analysis of observational studies assessing the effect of rheumatoid arthritis.

Additional file 10. GRADE assessment of the systematic review and meta-analysis of randomised trials assessing the effect of rheumatoid arthritis.

Additional file 5. Stratified analyses on the level of C-reactive protein in RA.

Traditional Cauchy-Stokes decomposition of velocity gradient tensor gives a symmetric and an anti-symmetric subtensors which are called the strain-rate and vorticity tensors. There are two problems with Cauchy-Stokes decomposition. The first one is that the anti-symmetric or vorticity tensor cannot represent the fluid rotation or vortex. The second one is that the symmetric (strain-rate) tensor cannot distinguish the stretching (compression) and shear. The stretching and shear are dependent on the coordinate or are not Galilean invariant. Since vorticity cannot distinguish between the non-rotational shear and the rigid rotation, vorticity has been decomposed to a rigid rotation called Liutex and anti-symmetric shear in our previous work. A Liutex-based principal coordinate was developed and the velocity gradient tensor was decomposed in the principal coordinate as a rigid rotation (Liutex tensor), a pure shear tensor and a stretching (compression) tensor, which is called the principal decomposition. However, the principal decomposition is made at each point which has own principal coordinate different from other points. This paper derives the principal decomposition in the original xyz coordinate system, and, therefore, provides a new tool for fluid kinematics to conduct the velocity gradient tensor decomposition to rigid rotation, pure shear, and stretching (compression) which is Galilean invariant and has clear physical meanings. The new velocity gradient tensor decomposition could become a foundation for new fluid kinematics.

Additional file 7. Influence of each study on CEC, HDL-C, CRP and ESR in RA.

Additional file 8. Sensitivity analysis using credibility ceilings of 10% for the meta-analyses investigating the effect in RA.

Additional file 1. Forest plot of the plasma levels of LDL (a), TC (b) and TG (c) for patients with RA versus control group in observational study.

Additional file 1: Table S1. The associations of serum total bilirubin with type 2 diabetes (sensitivity analysis 1). Table S2. The associations between serum total bilirubin and type 2 diabetes by body mass index (sensitivity analysis 2). Table S3. The associations of serum total bilirubin with type 2 diabetes (sensitivity analysis 3). Table S4. The associations between serum total bilirubin and type 2 diabetes by body mass index and waist circumference. Table S5. The associations of serum total bilirubin with glycohemoglobin and fasting blood glucose. Table S6. The associations of serum total bilirubin with HOMA-IR. Table S7. The associations of serum total bilirubin with lipid profile. Figure S1. The mediation model of c-reactive protein in the association of serum total bilirubin with glucose and glycohemoglobin. A: serum glucose; B: glycohemoglobin. In the mediation analysis, patients with self-reported use of insulin or other diabetes were excuded, finally, 14,449 paricipants with c-reactive protein data were used.

Although traditional vortex identification methods such as Q, Delta, Lambda2, Lambdaci remain popular in the identification and visualization of vortices, these methods count on shearing and stretching as a part of vortex strength. However, shearing and stretching do not contribute to fluid rotation. In this paper, the contamination effects of stretching and shearing of these methods are investigated and compared with Liutex method. From our investigation, the Liutex is an exact definition of fluid rotation or vortex, while other vortex identification methods are contaminated by stretching and shearing at different levels. The decomposition of the velocity gradient tensor can only be conducted in a so-called Principal Coordinate for uniqueness. The mathematical relation between Liutex and other vortex identification function are derived in this paper and then the effects of shearing and stretching on different vortex identification methods are studied. The mathematical formula and computation of the stretching and shearing effects on different schemes clearly show that the Liutex method has superiority over the other vortex identification methods as it only counts on local fluid rigid rotation while other methods count on stretching/compression and shearing as a part of the fluid rotation or vortex., 25 pages, 4 figures, 5206 words, pre-print

In recent years, energy storage power stations gradually merge into data centers. This paper studies the traffic scheduling problem of the energy storage data center network to improve network performance. A traffic scheduling scheme based on differential algorithms and congestion is proposed with the idea of separating the control plane from the data plane of the Software Defined Network. This scheme is divided into two parts: the introduction and improvement of the differential algorithm for unified scheduling of multiple traffic with the same sources and sinks; the concept of congestion degree is proposed for the remaining single traffic to be processed. This paper uses the Mininet network simulation platform and Ryu controller to perform simulation verification in four aspects of standardized throughput, link utilization, load balancing, and link bandwidth utilization. The comparative experiments show that the strategy proposed in this paper can greatly improve the network performance in the above aspects.

The Navier-Stokes (NS) partial differential equations, as the governing equation of fluid dynamics, are based on particles with zero volume. In such a condition, conservation law of moment of momentum is automatically satisfied, and thus NS equations only contain conservation of mass, momentum and energy. Because of the difficulty to get an analytical solution of NS equations, scientists develop finite element method (FEM) and finite volume method (FVM) to obtain approximate solutions. However, these methods are dependent on the size of finite volumes, which is not zero. Considering the size of the finite volume, conservation law of moment of momentum is no longer automatically satisfied and it is necessary to develop a new control equation to take effect of momentum into account. In this paper, new relations of reciprocal shear stresses are derived from conservation law of moment of momentum, and so are new constitutive relations and modified NS equations. The Liutex based NS equation may be the universal governing equations for both laminar and turbulent flow which is dominated by vortices and conservation of moment of momentum must be satisfied., Comment: 12 pages, 3 figures, 1911 words, pre-prints

Objective: The aim is to study the effects of metformin on the expression of 70 kDa ribosomal protein S6 kinase (P70S6k), insulin receptor substrate 1 (IRS-1), and IRS-1Ser307 phosphorylation in human luteinized granulosa cells. Methods: Granulosa cells in the experimental group were cultured in M199 medium containing 0.1 mmol/L metformin for 24 h and those in control group were cultured in M199 medium. The expression levels of P70S6k and IRS-1 mRNA were detected by reverse-transcriptiom polymerase chain reaction (RT-PCR) and real-time PCR. P70S6k, IRS-1, p-ser307-IRS-1, and p-thr389-P70S6k protein expression levels were detected by immunofluorescence and western blotting. Results: P70S6k mRNA level was higher and IRS-1 was significantly lower in the experimental group than those in the control group. IRS-1 and p-ser307-IRS-1 were expressed in cell plasma, and P70S6k and p-thr389-P70S6k were expressed in cell nucleus. The results of Western blot analysis indicated that the expression levels of P70S6k, p-thr389-P70S6k, IRS-1, and p-ser307-IRS-1 proteins had significant difference between the experimental group and the control group. Compared to the control group, the relative intensity illustrated that the expression levels of P70S6K and p-thr389-P70S6k significantly increased in the experimental group; however, those of IRS-1 and p-ser307-IRS-1 proteins significantly decreased. Conclusion: Metformin can inhibit the P70S6k mRNA and protein expression levels in the granulosa cells and improve insulin sensitivity by regulating IRS-1 expression through Akt/P70S6k/IRS-1-dependent pathway.

This paper aims to analyze the capacity of underground excavation to bear subgrade construction. A modelling approach using the FLAC3D software was proposed to evaluate the capability of the underground excavation beneath the Changli highway in Jiangxi, China. The model was supplemented by the implementation of the regional stress, the Hoek–Brown yield criterion, and the associated flow rule. Several beneficial consequences obtained from the evaluation suggest that the decision made on the prevention and treatment of karst collapse. An empirical equation was summarized via regression analysis to explicitly depict the relationship between the tectonic load and the capability of underground excavation. The material properties of limestone and the geometric conditions of underground excavation were found to significantly affect the cave collapse process. The bearing capacity of type II limestone is prominent, followed by type III limestone, while the bearing capacity of type IV limestone is not so satisfied. Caves with small size and thick roof seem to have more potential to bear subgrade construction.

Supplemental Digital Content is available in the text, The prognostic value and conflicting results of metastatic lymph node ratio (mLNR) on breast cancer have aroused an increasing concern. We aimed to evaluate the imperative of mLNR classification and prognostic factors in breast cancer with molecular subtypes. This study uses the database of surveillance, epidemiology, and end results (SEER) to investigate the imperative for reliable mLNR classification and critical prognostic factors in breast cancer with different molecular subtypes. The prognostic characteristics for disease-specific survival (DSS) of breast cancer were investigated in the SEER cohort (n = 3651). mLNR (P = .017) and histology grade (P

In this paper, a modified normalized Rortex/vortex identification method named Omega_R is presented to improve the original Omega_R method and cure the bulging phenomenon on the iso-surfaces caused by the original Omega_R method. Detailed mathematical explanations and the relationship with the Q criterion are described. In addition, the new developed formula does not require two original coordinate rotations, and the calculation is greatly simplified. The numerical results are demonstrated to show the effectiveness of the new modified normalized Rortex/vortex identification method., 2589 words, 8 pages and 10 figures

Vortex has been considered as the building block and muscle of turbulence for long time. A new physical quantity called Liutex (previously named Rortex) has been defined as the rigid rotation part of fluid motion. From DNS and experiment, forest of hairpin vortices has been found in flow transition and low Reynolds turbulence, but more and more one leg vortices appear in fully developed turbulence. This letter shows hairpin vortex is unstable. Hairpin vortex will weaken or lose one leg by the shear and vortex interaction. This conclusion is made by Liutex definition and mathematical analysis without any physical assumptions. The asymmetry of vortex is caused by the interaction of symmetric shear and symmetric Liutex due to the definition of Liutex, which considers the smaller element of a pair of vorticity elements as the rotational strength. For a 2-D fluid rotation, if a disturbance shear effects the larger element, the rotation strength will not be changed, but if the disturbance shear effects the smaller element, the rotation strength will be immediate changed due to the Liutex strength definition. For a rigid rotation, if both vorticity of the shear and Liutex have the same directions, e.g., clockwise, the Liutex strength will not be changed. If the vorticity of the shear and Liutex have different directions, e.g., one clockwise and one counterclockwise, the Liutex strength will be weakened. Then, the hairpin vortex could lose the symmetry and even deform to a one leg vortex. The one leg vortex cannot keep balanced, and the chaotic motion and flow fluctuation are doomed. This is considered as the mathematical foundation of turbulence formation. This theory has been checked and proved by our DNS results of boundary layer transition.

Background: To compare the clinical efficacy between Orthopilot navigation system and conventional manual surgery in total hip arthroplasty (THA). Methods: Electronic databases were searched to identify randomized controlled trials (RCTs) investigating Orthopilot navigation system versus conventional manual in patients undergoing THA. Outcome measurements include anteversion angle, inclination angle, preoperative leg length discrepancy, postoperative leg length discrepancy and femoral offset. Statistical software Stata 12.0 was used for data-analysis. Results: A total of 5 studies were finally included in this meta-analysis. The results showed that the conventional manual group have a less anteversion angle than that in Orthopilot navigation system group (weighted mean difference (WMD) = 4.67, 95% confidence interval (CI) = 3.53, 5.82, P = .000). And pooled analysis showed that the inclination angle in Orthopilot navigation group was less than that in conventional manual group (WMD = −4.19, 95% CI = −8.00, −0.37, P = .031). There was no significant difference between the preoperative leg length discrepancy and postoperative leg length discrepancy (P > .05). Orthopilot navigation system compared with conventional manual procedure was associated with decreased of femoral offset by 2.76 (WMD = −2.76, 95%CI = −3.90, −1.62, P = .000). Conclusion: Both Orthopilot navigation system and conventional THA result in significant improvements in patient function with similar overall complication rates and have their own edges in cup position.

Eulerian local region-type vortex identification criteria, including the criterion, the criterion and the criterion et al., are widely used for vortex identification due to the simplicity in applications. However, most of these criteria are based on a scalar quantity, unable to identify vortex axis (core) lines. On the other hand, the current line-type methods, which seek to extract line-type features such as vortex core lines, are not entirely satisfactory since most of these methods are based on vorticity or pressure minimum which will fail in many cases. To address this issue, a novel Liutex (previously named Rortex) based definition of vortex axis line is proposed in this paper. Mathematically, the vortex axis lines are defined by points where the gradient of Liutex magnitude is aligned with the direction of the Liutex vector, which implies that the cross product of the gradient of Liutex magnitude and the Liutex vector is equal to zero. A preliminary manual process for extracting vortex axis lines is presented. Two test cases, namely Burgers vortex and hairpin vortex, are examined to verify the proposed method., 20 pages and 5 color figures

In this study, the new concept of vortex core line based on Liutex definition is applied to demonstrate that vortex ring is not part of the Lambda-vortex and the generation of ring like vortex is formed separately from the Lambda-vortex. The proper orthogonal decomposition is also applied to analyze the Kelvin Helmholtz instability happening in hairpin ring areas of flow transition on the flat plate to understand the ring like vortex formation. The new identification method named modified Omega-Liutex method is efficiently used to visualize and observe the shapes of vortex structures in 3D. The streamwise vortex structure characteristics can be found in POD Mode1 as the mean flow. The other POD modes are in spanwise structures and have the fluctuation motions, which are induced by KH instability. Moreover, the result shows that fluctuated POD modes are in pairs and share the same characteristics such as amplitudes, mode shapes and time evolutions. The vortex core and POD results confirm that the Lambda-vortex is not self deformed to a hairpin vortex, but it is formed by the KH instability during the formation of Lambda vortex and hairpin vortex in boundary layer flow transition., Comment: 27 pages and 16 figures

In the present study, the physical meaning of vorticity is revisited based on the RS decomposition proposed by Liu et al. in the framework of Liutex (previously named Rortex), a vortex vector field with information of both rotation axis and swirling strength [ C. Liu et al., "Rortex-A new vortex vector definition and vorticity tensor and vector decomposition", Phys. Fluids 30, 035103 (2018)]. It is demonstrated that the vorticity in the direction of rotational axis is twice the spatial mean angular velocity in the small neighborhood around the considered point while the imaginary part of the complex eigenvalue ({\lambda}_ci) of the velocity gradient tensor (if exist) is the pseudo-time average angular velocity of a trajectory moving circularly or spirally around the axis. In addition, an explicit expression of the Liutex vector in terms of the eigenvalues and eigenvectors of velocity gradient is obtained for the first time from above understanding, which can further, though mildly, accelerate the calculation and give more physical comprehension of the Liutex vector., Comment: 21 pages, 10 figures

A series of thermal runaway (TR) tests are conducted on the 300 Ah large-scale lithium iron phosphate (LiFePO4) batteries under external heating. The combustion process of the battery can be divided into four stages, and the aggressive cylindrical flame is observed. Due to the battery's large size, the TR expanding process within the battery body is clearly observed based on the temperature rate curves of different surfaces. The flaming combustion accelerates the occurrence of TR but has little influence on the peak surface temperature. The cooling effect of safety valve opening on each thermocouple is influenced by the electrolyte distribution inside the cell. A real-scale scenario is considered to evaluate the fire-induced toxicity of an electric bus that a 10 cell pack combusts in a garage with fresh air renewal. The fractional effective dose is much greater than the critical value of 1, indicating the catastrophic toxicity. The air renewal rate required for safety is calculated to provide advice for the ventilation management of garage. The battery fire is compared with the pool and gas fires of common fuels. It is found that this large-scale LiFePO4 battery has the higher specific capacity and superior safety performance in the aspect of heat release features after comparing with previous LIB samples.

Lithium ion batteries (LIBs) have been widely used in various electronic devices, but numerous accidents related to LIBs frequently occur due to its flammable materials. In this work, the thermal runaway (TR) process and the fire behaviors of 22 Ah LiFePO4/graphite batteries are investigated using an in situ calorimeter. The cells are over heated using a heating plate. The heating plate is utilized to simulate the abuse process triggered by TR of the adjacent battery in modules. The fire behaviors, heat release rate (HRR), temperature characteristics of cell surface and flame, mass loss, voltage variation and gas release are obtained. For 100% state of charge (SOC) cells, the fire is blown out at the TR process. Jet fire is only observed for 50% and 100% SOC cells and the average trigger temperatures of TR are 198.6 and 184.8 °C for 50 and 100% SOC batteries, respectively. The state of charge of the cell has a significant influence on the peak HRR, total heat release (THR) and mass loss. HF and H2 are detected during combustion process. The productions of CO and HF increase as the increasing SOCs, which have much greater toxicity. And that of 100% SOC cells is much larger due to the flame being blown out. The relationship between TR and fire behaviors is revealed. Two failure modes are proposed to describe the fire behaviors at different phases. Based on the energy balance of the cell, the mechanism and phenomenon related to SOCs are discussed. From the safety perspective, several proposals are advanced for application and fire protection.

In recent years, the development of wireless charging Electric Vehicles (EV) is becoming more and more rapid, because the new energy supply mode----wireless power charging has the advantages of high space utilization, high security, more convenience, stronger user experience. The Influence of charging on life safety, as the research hotspot of EV's wireless charging, has attracted more and more attention and research at home and abroad. The electromagnetic safety evaluation in this article not only provides a theoretical foundation for the life safety analysis of EV's wireless charging, but also is conducive to the future application development. In this study, under the condition of transmission frequency and output power of 85 kHz and 11.4 kW respectively, the models of EV coil and adult body are simulated. The results of safety range and electromagnetic intensity in different positions are obtained and contrasted with International Commission for Non-Ionizing Radiation Protection (ICNIRP) standard. In order to confirm the reliability of the simulation results, we set up the experimental prototype about EV's wireless charging and do the electromagnetic exposure measurement. Finally the electromagnetic safety evaluation of EV charging system is carried out from the perspective of molecular biological experiments.

Electric vehicle dynamic wireless power charging technology is to lay the transmitting coil below the ground. When the electric vehicle with receiving coil is running on this road, the power grid is continuously transmitted to the driving motor of electric vehicle through transmitting and receiving coil, thus realizing the dynamic wireless charging of electric vehicle. In recent years, the dynamic wireless charging technology of electric vehicles has attracted more and more attention of research institutes because of its long endurance mileage, small carrying capacity of on-board batteries and flexible charging methods. In this paper, direct field-circuit coupling multi-physical field simulation is carried out to study the influence of parameters on the dynamic coupling process of the dynamic wireless charging system of electric vehicle. Through simulation analysis, the effect of different parameter changes on the system is effectively reflected. And the real working characteristics of the system are estimated.

In the era of internet of things, electronic devices are becoming ubiquitous. To perform secure tasks such as identification and authentication, security modules need to be embedded in such devices. Physical unclonable function (PUF) is an emerging security primitive to address vulnerability of the traditional data protection scheme that stores the secret keys in non-volatile memories. Despite various kinds of PUFs proposed so far, this dissertation investigates two most popular PUFs, which are Static Random Access Memory (SRAM) and Ring oscillator (RO) based PUFs. SRAM has recently been developed into a PUF for generating chip-unique signatures for hardware cryptography. The most compelling issue in designing a good SRAM-based PUF (SPUF) is that while maximizing the mismatches between the transistors in the cross-coupled inverters to improve the quality of SPUF, this process itself gives rise to increased memory read/write failures. For this reason, the memory cells of existing SPUFs cannot be reused as storage elements, which increases the overheads of cryptographic system where long signatures and high-density storage are both required. This thesis presents a novel design methodology for dual-mode SRAM cell optimization. The design conflicts are resolved by using word-line voltage modulation, dynamic voltage scaling, negative bit-line and adaptive body bias tech- niques to compensate for reliability degradation due to transistor downsizing. The augmented circuit-level techniques expand the design space to achieve a good solution to fulfill several otherwise contradicting key design qualities for both modes of operation, as evinced by the statistical analysis and simulation results based on complementary metal–oxide–semiconductor (CMOS) 45 nm bulk Predictive Technology Model. Using power-up reset to reuse SRAM as PUF suffers from two major constraints. First, it has limited entropy of only one response bit per cell. Second, as power-up reset has a global effect, extra storage is needed to temporarily buffer the original SRAM content before switching to PUF mode. This process has introduced extra area-power overhead as well as potential security leakage. The emerging dual-port (DP) SRAM cell offers attractive multiple access capability for low-power and high-speed memory transfer. By leveraging the forbidden contention state in one of its four multiple access modes, a new DP-SRAM based PUF is proposed to generate two independent response bits per cell and limit data buffering to only those cell content addressed by the challenge. Simulation results based on PTM 22nm LP CMOS model has corroborated its superior reliability, uniqueness and randomness. RO based PUF is an emerging hardware security primitive but its response reproducibility is susceptible to changes in operating conditions and device aging. Present solutions to increase RO PUF reliability either incur large hardware overhead or require sophisticated RO selection algorithm. This research exploits the optimal biasing of current starved (CS) inverter for the design of RO PUF with very high reliability against both temperature and voltage variations. With two additional transistors, the CS inverter can be adaptively biased at idle time and in active mode to significantly reduce the overall stress, making the proposed CS RO PUF robust against both environmental condition variations and aging. Without using error correction code, the reliability is further improved by a low-cost proximity detector circuit with a small sacrifice on challenge-response-pair (CRP) space. The correlation between successive RO pairs of different input challenges is also broken by an irregular clocking of the linear feedback shift register used to encipher the input challenges. Based on Monte Carlo simulation in TSMC 40nm CMOS process, the reliability of native PUF responses has been raised substantially from 89.78% for the regular RO PUF to 95.88% for the proposed CS RO PUF over a broad temperature range of -40 to 120◦C and ± 20% supply variation. With the proximity detector, the proposed Aging-resistant Current-starved RO (ACRO) PUF can attain 100% reliability statistically by discarding 34.47% fewer challenge-response pairs than the regular RO PUF. It is also ∼3.7x more aging resilient than existing aging-resilient RO PUFs with ∼2.38x lower power dissipation. Master of Engineering

The important effect of cave span, roof thickness and strength on the stability of cavern has been widely recognized, while the influence of geostress on the stability of karst cave is not yet clear. In order to explore the influence of geostress, this paper offers a numerical analysis program established on the basis of the geostress model and Coulomb-Navier yield criterion. The stability of karst cave under different geostress conditions is calculated respectively. And then, several beneficial results are produced from the analysis in order to facilitate decision making on the prevention and treatment of karst collapse. Finally, an engineering example is introduced to verify the validity of prediction.

In this paper we report geochemical and Nd-Sr isotopic data for a late Archean gneissic granitic pluton (Hengling pluton), an early Paleoproterozoic complex (Xipan complex) and a late Paleoproterozoic granitic pluton (Yunzhongshan granites) from the Luliang-Wutai terrain, North China, to trace the source of these late Archean-Paleoproterozoic granitoids and, particularly, to understand the nature and mechanism of continental growth at that time. The Hengling granitic gneisses (ca. 2.51 Ga) are characterized by high Na2O and LILEs, TTG-like REE patterns (highly depleted HREE and minor Eu anomalies) and moderately depleted Nd-Sr isotopic compositions (∍Nd(t) =1.2-2.7, ISr=0.7015-0.7019), and were considered as being products of arc magmatism that was developed upon the North China craton. The Xipan complex (ca. 2.2 Ga) contain gabbroic diorite and monzonite, mostly being Na2O-rich, highly fractionated REE patterns and isotopically enriched (∍Nd(t) =−1.5 to −4.1, ISr=0.7038-0.706). The gabbroic diorites probably originated from melting of an enriched mantle source, but significantly contaminated by lower crustal material, and the monzonites probably represent a product of a mixture between the gabbroic dioritic magma and granitic melts of crustal origin. The Yunzhongshan post-collisional granitoids (ca. 1.8 Ga) are characterized by high-K affinity and highly-enriched and homogeneous Nd isotopic compositions (∍Nd(t) = −4.9 to −5.7), although they split into two groups in terms of REE patterns: one group showing elevated HREE (and Sc, Y and Zr) with significant negative Eu anomalies and the other showing highly depleted HREE and, to a lesser extent, mid-REE with negligible Eu anomalies. These granites are genetically related to a process of extensional collapse of a thickened orogen. They formed through magma mixing between mantle-derived basaltic magmas and crust-derived granitic melts, followed by significant fractionation of ferromagnesian phases (like hornblende and Cpx) and feldspar and accessory zircons. Some Yunzhongshan granites show very old Nd model ages (2.9-3.0 Ga), suggesting the existence of continental crust older than 2.7 Ga, which is supported by our zircon Hf isotopic data for these granites.

In this study, we investigate the interaction between vortex rings behind MVG and the oblique shocks in the MVG controlled ramp flow at M=2.5 and Req=5760. Implicit large eddy simulation (ILES) method is used by solving the unfiltered form of the Navier-Stokes equations with the 5th order Bandwidth-optimized WENO scheme. The fully developed inflow is given by a series of turbulent profiles obtained from previous DNS simulation. It shows that the ring structure does not break down and keeps its topology after penetrating the strong shock wave and the oblique shocks is influenced a lot by the induced flow field from rings. The bump of the 3D shock wave surface is discovered and its mechanism is explained., 50th AIAA Aerospace Sciences Meeting

This paper is devoted to the investigation of the origin and mechanism of randomization in late boundary layer transition over a flat plate without pressure gradient. The flow randomization is a crucial phase before flow transition to the turbulent state. According to existing literatures, the randomization was caused by the big background noises and non-periodic spanwise boundary conditions. It was assumed that the large ring structure is affected by background noises first, and then the change of large ring structure affects the small length scales quickly, which directly leads to randomization and formation of turbulence. However, by careful analysis of our high order DNS results, we believe that the internal instability of multiple ring cycles structure is the main reason. What we observed is that randomization begins when the third cycle overlaps the first and second cycles. A significant asymmetric phenomenon is originated from the second cycle in the middle of both streamwise and spanwise directions. More technically, a visible asymmetric phenomenon in the middle vortex ring cycle starts at time step t=16.25T and x=838.9{\delta}in where the top and bottom level rings are still completely symmetric. The non-symmetric structure of middle level ring affects the small length scale in boundary layer bottom quickly. The randomization phenomenon spreads to top level through ejections. Finally, the whole flow domain becomes randomized. A hypothesis of C- and K-types shift is given as a possible mechanism of flow randomization., Comment: 51st AIAA Aerospace Sciences Meeting. arXiv admin note: substantial text overlap with arXiv:1402.5873

In this paper, the flow around each ring-like vortex is investigated by high order DNS including first sweep, first ejection, second sweep, second ejection, positive spike, momentum deficit, vortex shape, vortex location, strength of sweeps, etc. Meanwhile, the mechanism about formation of momentum deficit is deeply studied. A new mechanism on how the multiple rings are formed one by one found both by experiment and by DNS in late boundary layer transition is presented. It also reveals that the relation between streamwise vortex and spanvise vertex rings, and how the vorticity is transferred between them.

The small vortex generation is a key issue of the mechanism for late flow transition and turbulence generation. It was widely accepted that small length vortices were generated by large vortex breakdown. According to our recent DNS, we find that the hairpin vortex structure is very stable and never breaks down to small pieces. On the other hand, we recognize that there are strong positive spikes besides the ring neck in the spanwise direction. The strongly positive spikes are caused by second sweeps which are generated by perfectly circular and perpendicularly standing vortex rings. The second sweep brings energy from the invisid region downdraft to the bottom of the boundary layers, which generates high shear layers around the positive spikes.Since the high shear layer is not stable, all small length scales (turbulence) are generated around high shear layers especially near the wall surface (bottom of boundary layers). This happens near the ring neck in the streamwise direction and besides the original vortex legs in the spanwise direction.The small length scales then rise up from the wall surface and travel to the upper boundary layer., Comment: 49th AIAA Aerospace Sciences Meeting. arXiv admin note: text overlap with arXiv:1402.5183

The inhalation therapy is a cornerstone in asthma treatment. A disease characterized by episodes of wheezing, breathing difficulties, chest tightness and coughing. Essentially it is a chronic inflammatory disorder associated with airway hyper responsiveness [1]. This disease already affects over 300 million people worldwide, growing at a rate of 50% per decade, and causes the death of 220 thousand per year [1].