Numerical Investigations on Wedge Control of Separation of a Missile from an Aircraft

To make the missile safely separate from the internal weapons bay, a wedge flow control device is mounted on the front of the bay to control the variation of flow during the separation. The numerical simulations of missile separation without and with wedge flow control device under different sizes are carried out. The flow fields of different separation processes are obtained and discussed; the aerodynamic parameters and trajectory parameters of missile of different cases are illustrated and compared. Results show that, the wedge flow control device can accelerate the missile separation and has the effect of regulating the angular motion of missile. The influence of the wedge height is stronger than that of its length on the center of gravity motion and angular motion of missile

An Integrated Analysis of miRNA and mRNA Expressions in Non-Small Cell Lung Cancers

Using DNA microarrays, we generated both mRNA and miRNA expression data from 6 non-small cell lung cancer (NSCLC) tissues and their matching normal control from adjacent tissues to identify potential miRNA markers for diagnostics. We demonstrated that hsa-miR-96 is significantly and consistently up-regulated in all 6 NSCLCs. We validated this result in an independent set of 35 paired tumors and their adjacent normal tissues, as well as their sera that are collected before surgical resection or chemotherapy, and the results suggested that hsa-miR-96 may play an important role in NSCLC development and has great potential to be used as a noninvasive marker for diagnosing NSCLC. We predicted potential miRNA target mRNAs based on different methods (TargetScan and miRanda). Further classification of miRNA regulated genes based on their relationship with miRNAs revealed that hsa-miR-96 and certain other miRNAs tend to down-regulate their target mRNAs in NSCLC development, which have expression levels permissive to direct interaction between miRNAs and their target mRNAs. In addition, we identified a significant correlation of miRNA regulation with genes coincide with high density of CpG islands, which suggests that miRNA may represent a primary regulatory mechanism governing basic cellular functions and cell differentiations, and such mechanism may be complementary to DNA methylation in repressing or activating gene expression

Identification of Genome-Wide Variations among Three Elite Restorer Lines for Hybrid-Rice

Rice restorer lines play an important role in three-line hybrid rice production. Previous research based on molecular tagging has suggested that the restorer lines used widely today have narrow genetic backgrounds. However, patterns of genetic variation at a genome-wide scale in these restorer lines remain largely unknown. The present study performed re-sequencing and genome-wide variation analysis of three important representative restorer lines, namely, IR24, MH63, and SH527, using the Solexa sequencing technology. With the genomic sequence of the Indica cultivar 9311 as the reference, the following genetic features were identified: 267,383 single-nucleotide polymorphisms (SNPs), 52,847 insertion/deletion polymorphisms (InDels), and 3,286 structural variations (SVs) in the genome of IR24; 288,764 SNPs, 59,658 InDels, and 3,226 SVs in MH63; and 259,862 SNPs, 55,500 InDels, and 3,127 SVs in SH527. Variations between samples were also determined by comparative analysis of authentic collections of SNPs, InDels, and SVs, and were functionally annotated. Furthermore, variations in several important genes were also surveyed by alignment analysis in these lines. Our results suggest that genetic variations among these lines, although far lower than those reported in the landrace population, are greater than expected, indicating a complicated genetic basis for the phenotypic diversity of the restorer lines. Identification of genome-wide variation and pattern analysis among the restorer lines will facilitate future genetic studies and the molecular improvement of hybrid rice

Efficacy and safety of baroreflex activation therapy for treatment of resistant hypertension: a systematic review and meta-analysis

To provide definite evidence for the anti-hypertensive benefit of Baroreflex Activation Therapy (BAT) for resistant hypertension, we performed a systematic review and meta-analysis to evaluate the efficacy and safety of BAT. Electronic searches were conducted in PubMed, EMBASE, The Cochrane Library and Web of Science. Two reviewers independently determined the eligibility of studies and extracted the data. The quality of all included studies was evaluated by the use of the Newcastle Ottawa Scale (NOS). Disagreements were settled through discussion. Twelve studies, included one randomized clinical trials (RCTs) and eleven prospective studies were eligible for qualitative analysis and five prospective studies were selected for meta-analysis. The data of analysis showed office systolic blood pressure (SBP)(WMD = −24.01, 95% CI = −28.65 to −19.36, P= 0.753I2 = 0.0%) and diastolic blood pressure (DBP)(WMD = −12.53, 95% CI = −15.82 to −9.24,P = 0.893,I2 = 0.893) decreased by BAT treatment.The effect on SBP was both significant in the Barostim neo TM device (WMD = −22.49, 95% CI = −29.13 to 15.84, P= 0.443; I2 = 0.0%) and Rheos System (WMD = 25.46, 95% CI = −31.96 to −18.96, P= 0.703; I2 = 0.0%). Our study found office BP were significantly decreased by BAT treatment, but available evidence is limited by risk of bias, small sample size, and few RCTs. Thus, there is presently insufficient evidence to fully evaluate the efficacy and safety of BAT for Patients with Resistant Hypertension. Additional high-quality RCT research with long-term follow-up is required

Hot Deformation Behavior and Microstructure Evolution of Al-7.92 Zn-1.64 Mg-2.00 Cu Alloy

During the thermal deformation of aluminum alloy materials, the deformation conditions such as deformation volume, temperature and strain rate are important factors that influence the deformation mechanisms such as work hardening, dynamic recovery and dynamic recrystallization. Under the interaction of different deformation mechanisms, the properties of aluminum alloy materials will change significantly. In this study, isothermal hot compression experiments were conducted on the Al-7.92 Zn-1.64 Mg-2.00 Cu alloy to analyze its hot flow behavior (T = 250~450 °C, ɛ̇ = 0.001~1 s−1). The obtained flow behavior data were used to construct an Arrhenius-type constitutive equation and processing maps, investigating organizational evolution under diverse hot deformation conditions. The results show that the energy dissipation rate can reach 0.37 when the deformation temperature T = 380~450 °C and the strain rate ɛ̇ −1, suggesting that the material is most suitable for thermal deformation processing at high temperatures and low strain rates. At a strain rate of 0.1 s−1 and a temperature of 450 °C, the percentage of recrystallized grains and substructures increased by 7.20% and 3.14%, respectively, compared to 300 °C, which is due to the severe dynamic recovery and dynamic recrystallization. At 350 °C and 0.1 s−1, there was a higher percentage of recrystallized grains and substructures, 5.44% and 5.87% higher, respectively, than at a strain rate of 1 s−1, indicating that the release of dislocation accumulation due to deformation storage energy will be more favored at low strain rates, which promotes the enhancement of the dynamic recrystallization mechanism

Reduction of Residual Quenching Stresses in 2A14 Aluminum Alloy Tapered Cylinder Forgings via a Novel Cold Bulging Process

This study combined finite element method (FEM) simulations and physical experiments to develop a novel cold bulging process, with the aim of studying and mitigating the quenching residual stresses in 2A14 tapered cylinder forgings. The samples underwent cold bulging at different ratios (0–4.0%) to evaluate the residual stress reduction performance (via the hole-drilling strain-gauge method) and the improvements in their mechanical properties. The FEM simulation and experimental results revealed that our proposed cold bulging process reduced the quenching residual stresses by up to 85–87%. The density and uniformity of the precipitated phases increased along with the extent of cold bulging, as confirmed by transmission electron microscope (TEM) observations. Furthermore, compared to the unprocessed samples, the tensile and yield strengths, and elongation of the samples with 3% cold bulging were significantly enhanced (65 MPa, 55 MPa, and 1.7%, respectively)

Influence of thermomechanical processing on coarse particles, grain structure, and mechanical properties of Al–Cu alloy rings

Rings made of 2219 Al alloy are typically manufactured by multi-directional forging (MDF) and ring rolling at 460 °C, followed by heat treatment. However, this process often results in coarse elongated grains and a large number of coarse Al2Cu particles, resulting in rings with poor mechanical properties. As a strategy to refine the microstructure and improve the mechanical properties, a novel thermomechanical process was tested for ring manufacturing, with MDF at 510 °C and ring rolling at 240 °C. The results showed that use of MDF at higher temperatures resulted in increased spherical shapes and decreased numbers of coarse Al2Cu particles due to more complete dissolution. Decreasing the rolling temperature from 460 °C to 240 °C resulted in finer grain structure due to the increased nucleation ratio of static recrystallization during subsequent solution heat treatment. Samples prepared using this novel process exhibited fine equiaxed grains with sufficient dissolving of coarse Al2Cu particles, thus this method significantly improved the mechanical properties of the prepared material and decreased the anisotropy in three orthogonal directions

Influence of Temperature-Dependent Properties of Aluminum Alloy on Evolution of Plastic Strain and Residual Stress during Quenching Process

To lessen quenching residual stresses in aluminum alloy components, theory analysis, quenching experiments, and numerical simulation were applied to investigate the influence of temperature-dependent material properties on the evolution of plastic strain and stress in the forged 2A14 aluminum alloy components during quenching process. The results show that the thermal expansion coefficients, yield strengths, and elastic moduli played key roles in determining the magnitude of plastic strains. To produce a certain plastic strain, the temperature difference increased with decreasing temperature. It means that the cooling rates at high temperatures play an important role in determining residual stresses. Only reducing the cooling rate at low temperatures does not reduce residual stresses. An optimized quenching process can minimize the residual stresses and guarantee superior mechanical properties. In the quenching process, the cooling rates were low at temperatures above 450 °C and were high at temperatures below 400 °C

Robust Task-Oriented Dialogue Generation with Contrastive Pre-training and Adversarial Filtering

Data artifacts incentivize machine learning models to learn non-transferable generalizations by taking advantage of shortcuts in the data, and there is growing evidence that data artifacts play a role for the strong results that deep learning models achieve in recent natural language processing benchmarks. In this paper, we focus on task-oriented dialogue and investigate whether popular datasets such as MultiWOZ contain such data artifacts. We found that by only keeping frequent phrases in the training examples, state-of-the-art models perform similarly compared to the variant trained with full data, suggesting they exploit these spurious correlations to solve the task. Motivated by this, we propose a contrastive learning based framework to encourage the model to ignore these cues and focus on learning generalisable patterns. We also experiment with adversarial filtering to remove "easy" training instances so that the model would focus on learning from the "harder" instances. We conduct a number of generalization experiments -- e.g., cross-domain/dataset and adversarial tests -- to assess the robustness of our approach and found that it works exceptionally well