Efficacy of Online Learning and Influence on Skin and Eyes Among College Students

To evaluate the efficacy of online learning and explore the impact of long-term use of electronic products on facial skin as well as eyes.A cross-sectional survey was conducted to 180 sophomores in Xi′an Jiaotong University by cluster random sampling from September to October 2021.The questionnaire covering study condition,skin lesion and Ocular Surface Disease Index.χ_(2) test was used to compare the facial skin condition among different groups,and spearman correlation test was used to test the correlation of rank data.During online education,students′learning pressure is reduced,their autonomy is improved,and the learning efficiency is reduced.There were differences in the incidence of facial itching and papules among different groups.Duration of use of electronic products was positively correlated with the facial itching,with an r value of 0.231(P<0.05);the proportion of pigmentation in non-blue light protection groups(12.8%)was higher than that in blue light protection groups(1.7%),the difference was statistically significant(χ_(2)=8.384,P<0.05).The prevalence of dry eye among college students is 66.7%,and the proportion of moderate to severe dry eye is 34.5%.The study autonomy has been improved during online teaching.Long-term use of electronic products and no blue light protection have an impact on facial skin.Students should enhance the knowledge of skin-care and eye-care and develop better habits.

CORBA组件运行和开发环境研究

提出了一个符合通用请求代理体系结构 (CORBA )规范的软件组件运行环境的设计 ,作为CORBA组件的运行时刻支持平台 .它独立于软件组件 ,负责组件的装入、管理和调度等工作 .在研究中 ,采用当前先进的软件组件“容器”思想 ,将所有的软件组件纳入同一进程中运行 .在设计中 ,充分利用了对象请求代理 (ORB)核心所具有的功能 ,并针对CORBA组件设计了组件开发环境 ,使软件开发工作具有一定的自动化程度 ,提高了组件开发的质量和效率 .

快速原型虚拟逼真设计原理及体系结构

在分析设计的特点和发展趋势的基础上 ,提出快速原型虚拟逼真设计 ,并对其特点和原理进行了讨论 .快速原型虚拟逼真设计是面向并行工程 ,基于虚拟原型和虚拟环境仿真的设计 ,强调虚拟原型的快速生成与演化 .在关键技术、原型系统以及开发环境三个层次上论述了快速原型虚拟逼真设计的研究 .提出快速原型虚拟逼真设计模型以及基于该模型的体系结构 .

局内电梯调度问题与竞争算法

经典的优化理论大多是在已知条件不变的基础上给出最优方案 (即最优解 ) ,其最优性在条件发生变化时就会失去。局内问题与竞争算法则是针对特定的优化问题来研究这样的方法 ,它在变化因素的每一个特例中都能给出一个方案 ,使得这一方案所得到的解离最优方案给出的解总在一定的比例之内。本文首先提出了局内电梯调度问题 ,设计了解决该问题的两个不同的竞争算法 ,并证明了这两个竞争算法的竞争比分别为k+2 和n-k +1,其中k为电梯的个数 ,n为楼层数。

Aluminum matrix composite reinforced by in-situ formed intermetallic Al_3Ti

The reinforced phase of in situ formed intermetallic compound Al 3Ti with grain size about 0.5?μm in the aluminum matrix composite was achieved by the method of liquid solid reaction under specific condition. The orientations were also studied. The results show that under T6 heat treatment regime, the tensile strength, hardness, elastic modulus and elongation of Al 3Ti/ZL101 in situ composite are increased by 32.8%, 14.4%, 19.2% and 14.6% respectively in comparison with those of ZL101. Al 3Ti is uniformly distributed in α (Al) matrix with a clear phase interface, and the orientation relationship between Al 3Ti and α (Al) is (006) Al 3Ti ∥ (02-2) Al , -22] Al 3Ti ∥ Al 3Ti ∥-0] Al . The strengthening mechanisms of Al 3Ti/ZL101 in situ composite is proved to be caused by fine grain size, spreading distribution and dislocation multiplication. Al . The strengthening mechanisms of Al 3Ti/ZL101 in situ composite is proved to be caused by fine grain size, spreading distribution and dislocation multiplication.

Realization of Wavelet Transform Using SAW Devices

Based on the characteristics of surface acoustic wave(SAW) devices, the theory for realizing wavelet transform (WT) by SAW is deduced. Simulated experiment shows that the method of implementing WT using SAW devices has virtues of high speed and utility and is compatible with digital technique. It is important to implement wavelet transform.

Effect of thermal residual stresses on yielding behavior under tensile or compressive loading of short fiber reinforced metal matrix composite

Using large strain two dimension axisymmetric elasto plastic finite element method and the modified law of mixture, the effects of thermal residual stresses on the yielding behavior of short fiber reinforced metal matrix composite and their dependencies on the material structure parameters (fiber volume fraction, fiber aspect ratio and fiber end distance) were studied. It is demonstrated that the stress strain partition parameter can be used to describe the stress transfer from the matrix to the fiber. The variation of the second derivation of the stress strain partition parameter can be used to determine the elastic modulus, the proportion limit, the initial and final yield strengths. In the presence of thermal residual stress, these yielding properties are asymmetric and are influenced differently by the material structure parameters under tensile and compressive loadings.

Effects of Mo substituted Nb on magnetic properties of Finemet alloy

Different Mo contents have been added into traditional Finemet alloy to form Fe 73.5 Cu 1Nb 3- x Mo x Si 13 B 9.5 ( x =0～3) alloys. The change in DC and AC magnetic properties with Mo for Nb substitution was investigated. The results show that, with adding Mo, although the DC relative permeability decreases and the coercive force increases slightly, the saturation flux density B S can be increased, and the core loss of the alloy can be decreased. The AC permeability of samples contained Mo is higher than that of alloy without Mo content. Fe 73.5 Cu 1Nb 1Mo 2Si 13 B 9.5 alloy has the highest saturation flux density B S. Fe 73.5 Cu 1Nb 2Mo 1Si 13 B 9.5 alloy has the best frequency dependence on the AC permeability and core loss.

Investigation of Unsteady Flow in a Diffuser Pump

Flow in pumps is essentially three-dimensional and unsteady, and it has much influence on the pump hydraulic performance and structural vibration. This paper presents a numerical methodology developed for modeling such complicated flows. Three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations, together with standard k-Ε equation, describe the unsteady-turbulent flow in the pumps. System characteristics are incorporated into the pump CFD models to allow for fluid acceleration in the piper Arbitrary Sliding Interface (ASI) is used to simulate the relative movement between the impeller and stationary components; a numerical analysis is carried out for the entire circumference to consider the asymmetrical flow physics during the stall condition. Combination of these techniques has captured the realistic unsteady flow physics in the pumps and it permits good prediction for the pump off-design performance.

Investigation on Properties of Pb-Sb-Re Alloy

The mechanical properties, microstructures of as-cast Pb-Sb-Re alloy and of traditional Pb-Sb alloy were studied. The anodic corrosion layers formed at 0.9 V for 4 h in 4.5 mol·L -1 sulfuric acid solution were investigated using A.C impedance. The results show that the strength of Pb-Sb-Re alloy is slightly decreased, while the tenacity is increasing rapidly, which is helpful for the later manufacture of grid alloy material, and the anodic corrosion layer of Pb-Sb-Re alloy has better conductivity than that of traditional Pb-Sb alloy. It is shown that cerium can inhibit the development of Pb(Ⅱ) compound in anodic corrosion scale, and this can compensate for the effect of premature capacity loss for the low Sb content. In addition, cerium promotes the corrosion-resistant behavior of Pb-Sb alloy with low Sb content.

Crosstalk between CpG Methylation and Polymorphisms (CpG-SNPs) in the Promotor Region of DIO2 in Kashin-Beck Disease

Objective This study was designed to determine the methylation profile of four CpGs and the genotypes of two CpG-SNPs located in promoter region of DIO2 in patients with Kashin-Beck disease(KBD).We also analyzed the interaction between the CpGs methylations and CpG-SNPs.Methods Whole blood specimens were collected from 16 KBD patients and 16 healthy subjects.Four CpGs and two CpG-SNPs in the promoter regions of DIO2 were detected using matrix-assisted laser desorption ionization time of flight mass spectrometry(MALDI-TOF-MS).The CpGs methylation levels were compared between samples from KBD patients and healthy subjects.The methylation levels were also analyzed in KBD patients with different CpG-SNP genotypes.Results The mRNA expression of DIO2 in whole blood of KBD patients was significnatly lower than in healthy controls(P<0.05).The methylation levels of DIO2-1_CpG_3 in KBD patients were significantly higher than those in healthy controls(P<0.05).The methylation levels of four CpGs were not significantly different between KBD patients and healthy controls.The methylation level of DIO2-1_CpG_3 in the promoter region of DIO2 in KBD patients with GA/AA genotype was significantly higher than that of KBD patients with GG genotype(P<0.05).Conclusion The methylation level of DIO2 increases in KBD patients.Similar trends exist in KBD carriers of variant genotypes of CpG-SNPs DIO2 rs955849187.

Effect of laser surface melting treatment on properties of electric copper busbar joints

Electrical conductance and temperature of electric copper busbar joints were measured under different torque moments. Experimental results show that laser surface melting can increase hardness and refine structure of the copper, and it does not deteriorate electric resistance. Meanwhile, the temperature of laser treated joints under electric current is slightly lower than that of original sample. Salt spray test shows that laser treated sample has better salt spray corrosion resistance than the original sample does. The electric resistance of both laser treated and original samples are increased with salt spray time. For the same salt spray time, the electric resistance of busbar joint is decreased with increasing torque moment.

Neuroprotection of total steroid saponins from Dioscorea zingiberensis C.H.Wright against transient focal cerebral ischemia-reperfusion injury in rats via its anti-inflammatory and anti-apoptotic effects

OBJECTIVE The total steroid saponins(TSSN)isolated from Dioscorea zingiberensis C.H.Wright(D.zingiberensis)has shown a variety of beneficial bioactivities.However,there are no reports about the neuroprotective effects of the TSSN until now.Therefore,we explored the neuroprotective effects of TSSN on rats against transient focal cerebral ischemia-reperfusion(I/R)and the underlying mechanisms.METHODS The healthy adult Sprague-Dawley rats were randomly assigned into six groups.After pre-treatment with the TSSN intragastrically for six days,the rats were subjected to the ischemia injury by the surgery of middle cerebral artery occlusion(MCAO)for 90 min.Some indexes were evaluated and detected.RESULTS As compared to the I/R group,TSSN group of rats,especially given the 30 mg·kg^-1 of TSSN,not only marked reduction in the neurological deficit scores,cerebral infarct volume,and brain edema,but also an increase in neuron survival(Nissl bodies)in the hippocampal cornuammons 1(CA1)and cortex hemisphere of the ipsilateral ischemia.At the same time,the inflammatory cytokines in serum induced by MCAO were significantly alleviated by the TSSN pre-administration.What′s more,the increase of caspase-3 was evidently reduced in the CA1 and cortex of the hemisphere injured brain.Finally,the down-regulating anti-apoptotic Bcl-2 and up-regulating pro-apoptotic Bax proteins were obviously suppressed.CONCLUSION TSSN plays a potential neuroprotective role against a severe injury induced by transient focal cerebral ischemic reperfusion in a rat experimental model,and this role may be mediated by its antiinflammatory and anti-apoptotic actions.

Current Practice in Measuring the Quality of Conceptual Models:Challenges and Research

How to measure the quality of conceptual models is an important issue in the IS field and related research. This paper conducts a review of research in measuring conceptual model quality and identifies the major theoretical and practical issues that need to be addressed in future studies. We review current classification frameworks for conceptual model quality and practice of measuring conceptual model quality. Based on the review, challenges for studies of measuring the quality of conceptual models are proposed and these challenges are also research points which should be strengthened in future studies.

A Measure of Learning Model Complexity by VC Dimension

When developing models there is always a trade-off between model complexity and model fit. In this paper, a measure of learning model complexity based on VC dimension is presented, and some relevant mathematical theory surrounding the derivation and use of this metric is summarized. The measure allows modelers to control the amount of error that is returned from a modeling system and to state upper bounds on the amount of error that the modeling system will return on all future, as yet unseen and uncollected data sets. It is possible for modelers to use the VC theory to determine which type of model more accurately represents a system.

Bioinspired drug-delivery system emulating the natural bone healing cascade for diabetic periodontal bone regeneration

Diabetes mellitus(DM)aggravates periodontitis,resulting in accelerated periodontal bone resorption.Disordered glucose metabolism in DM causes reactive oxygen species(ROS)overproduction resulting in compromised bone healing,which makes diabetic periodontal bone regeneration a major challenge.Inspired by the natural bone healing cascade,a mesoporous silica nanoparticle(MSN)-incorporated PDLLA(poly(DL-lactide))-PEG-PDLLA(PPP)thermosensitive hydrogel with stepwise cargo release is designed to emulate the mesenchymal stem cell“recruitment-osteogenesis”cascade for diabetic periodontal bone regeneration.During therapy,SDF-1 quickly escapes from the hydrogel due to diffusion for early rat bone marrow stem cell(rBMSC)recruitment.Simulta-neously,slow degradation of the hydrogel starts to gradually expose the MSNs for sustained release of metformin,which can scavenge the overproduced ROS under high glucose conditions to reverse the inhibited osteogenesis of rBMSCs by reactivating the AMPK/β-catenin pathway,resulting in regulation of the diabetic microenvironment and facilitation of osteogenesis.In vitro experiments indicate that the hydrogel markedly restores the inhibited migration and osteogenic capacities of rBMSCs under high glucose conditions.In vivo results suggest that it can effectively recruit rBMSCs to the periodontal defect and significantly promote periodontal bone regeneration under type 2 DM.In conclusion,our work provides a novel therapeutic strategy of a bioinspired drug-delivery system emulating the natural bone healing cascade for diabetic periodontal bone regeneration.

Efficient Visual Recognition:A Survey on Recent Advances and Brain-inspired Methodologies

Visual recognition is currently one of the most important and active research areas in computer vision,pattern recognition,and even the general field of artificial intelligence.It has great fundamental importance and strong industrial needs,particularly the modern deep neural networks(DNNs)and some brain-inspired methodologies,have largely boosted the recognition performance on many concrete tasks,with the help of large amounts of training data and new powerful computation resources.Although recognition accuracy is usually the first concern for new progresses,efficiency is actually rather important and sometimes critical for both academic research and industrial applications.Moreover,insightful views on the opportunities and challenges of efficiency are also highly required for the entire community.While general surveys on the efficiency issue have been done from various perspectives,as far as we are aware,scarcely any of them focused on visual recognition systematically,and thus it is unclear which progresses are applicable to it and what else should be concerned.In this survey,we present the review of recent advances with our suggestions on the new possible directions towards improving the efficiency of DNN-related and brain-inspired visual recognition approaches,including efficient network compression and dynamic brain-inspired networks.We investigate not only from the model but also from the data point of view(which is not the case in existing surveys)and focus on four typical data types(images,video,points,and events).This survey attempts to provide a systematic summary via a comprehensive survey that can serve as a valuable reference and inspire both researchers and practitioners working on visual recognition problems.