改进YOLOv7算法的钢材表面缺陷检测研究

当前,基于深度学习的智能检测技术逐步应用于钢材表面缺陷检测领域,针对钢材表面缺陷检测精度低的问题,提出一种高精度实时的缺陷检测算法CDN-YOLOv7。加入CARAFE轻量化上采样算子来改善网络特征融合能力,融合级联注意力机制和解耦头重新设计YOLOv7检测头网络,旨在解决原始头网络特征利用效率不高的问题,使其充分利用各尺度、通道、空间的多维度信息,提升复杂场景下模型表征能力。引入归一化Wasserstein距离重新设计Focal-EIoU损失函数,提出NF-EIoU替换CIoU损失,平衡各尺度缺陷样本对Loss的贡献,降低各尺度缺陷的漏检率。实验结果表明,CDN-YOLOv7的检测精度可达80.3%,较于原YOLOv7精度提升了6.0个百分点,模型推理速度可达60.8帧/s,满足实时性需求,CDN-YOLOv7在提升各尺度缺陷检测精度的同时显著降低了缺陷的漏检率。

Long-term thinning decreases the contribution of heterotrophic respiration to soil respiration in subalpine plantations

Interest in the dynamics of soil respiration(R_(S))in subalpine forest ecosystems is increasing due to their high soil carbon density and potential sensitivity to environmental changes.However,as a principal silvicultural practice,the long-term impacts of thinning on R_(S) and its heterotrophic and autotrophic respiration components(R_(h) and Ra,respectively)in subalpine plantations are poorly understood,espe-cially in winter.A 3-year field observation was carried out with consideration of winter CO_(2) efflux in middle-aged sub-alpine spruce plantations in northwestern China.A trench-ing method was used to explore the long-term impacts of thinning on Rs,Rn and R_(a).Seventeen years after thinning,mean annual Rs,Rn and R_(a) increased,while the contribu-tion of R_(h) to R_(s) decreased with thinning intensity.Thinning significantly decreased winter R,because of the reduction in R_(n) but had no significant effect on Ra.The temperature sensitivity(Q_(10))of R_(h) and R_(a) also increased with thinning intensity,with lower Q_(10) values for R_(h)(2.1-2.6)than for Ra(2.4-2.8).The results revealed the explanatory variables and pathways related to R_(n) and R_(a) dynamics.Thinning increased soil moisture and nitrate nitrogen(NO_(3)^(-)-N),and the enhanced nitrogen and water availability promoted R_(h) and R_(a) by improving fine root biomass and microbial activity.Our results highlight the positive roles of NO_(3)^(-)-N in stimulating R_(s) components following long-term thinning.Therefore,applications of nitrogen fertilizer are not recommended while thinning subalpine spruce plantations from the perspective of reducing soil CO_(2) emissions.The increased Q_(10) values of R_(s) components indicate that a large increase in soil CO_(2) emissions would be expected following thinning because of more pronounced climate warming in alpineregions.

虚拟实验教学平台EVE-NG的应用

文章以计算机网络专业课程为例,利用最新的EVE-NG虚拟化技术,使师生能在一台个人电脑上架设小型局域网和大型广域网的硬件环境,配备各类服务器和渗透测试系统的软件环境,搭建出与真实生产环境一致的综合实训环境,实现在校学习实验与在企业工作环境的零距离对接,激发学生的学习兴趣,提高学生的动手能力,使学生更具发展潜力和竞争力。

基于虚拟化技术和工单制任务驱动的“1+X”课证融合的实施

文章探讨了在高职计算机专业群实施学分银行制,确保计算机专业群各专业的课证互认和"1+X"课证融合的实施;构建基于虚拟化技术的实训环境,解决了设备发展快、淘汰快、学习内容落后于企业真实环境的问题,为"1+X"课证融合打下基础;基于工单制设计和实施三类任务,即健全人格类任务、综合项目类任务和启发发现类任务,让学生学会自我发展规划,激发学生的学习动机、培养学生良好的行为习惯和创新思维,培养学生运用自主学习策略和合作学习策略的能力,拓展学生的就业能力和创业能力,提高学生的职业素养,使他们具备可持续发展的能力,并能在未来不断地进行自我提升。

虚拟化技术及其在计算机网络专业课程中的应用

通过虚拟化技术,一台真机可仿真成多台服务器和网络设备,解决计算机网络专业教学实训设备不足、实训场景不易搭建、不易重复利用以及真实设备无法为实训的不同阶段设置断点等问题,因此,相关课程的教学及实验向虚拟化切换势在必行。文章以VMware Workstation为例,介绍了虚拟化技术在教学中的应用。

基于双稀疏表示的无监督属性选择算法

由于大量无类标签数据需要降维处理,近年来无监督属性选择学习受到越来越多的关注。通过将两种稀疏表示和属性自表达损失函数嵌入到同一个学习框架中,提出了一种新的无监督属性选择算法。首先,利用属性自表达技术重构数据,使每一重构属性为所有原始属性的线性表征,加强属性关联性。然后,分别利用l_(2, p)范数正则项和l_(1)范数正则项使权重系数矩阵稀疏,剔除冗余无关属性,实现属性选择目的。最后,将约简后的低维数据集送入支持向量机中获得分类结果,以此评判属性选择算法是否有效。对多个真实数据集进行实验,实验结果显示,所提算法的降维效果优于一般常用算法。

中国2000–2020年积雪反照率遥感产品

积雪反照率是积雪反射能量与入射能量的比值,它量化了大气与积雪之间的辐射相互作用,在局部或全球能量收支平衡中有着重要意义。本文基于渐近辐射传输模型发展了适应中国区域积雪特点的反照率反演算法,以MODIS地表反射率产品作为输入,生产了中国2000–2020年积雪反照率的逐日和八天合成去云的遥感产品。利用多种地面站点和样方的积雪反照率观测数据,对产品开展综合验证分析,结果表明产品的均方根误差、相关系数、平均偏差均优于国际同类产品。产品可为我国积雪资源分布调查提供数据支持,满足我国辐射、气候、环境、生态等相关研究的应用需求。

七方胃痛方加减结合西医常规治疗慢性胃炎伴肠化生

目的观察七方胃痛方加减结合西医常规治疗慢性胃炎伴肠上皮化生患者的疗效。方法该次研究对象为64人,将患者随机分为2组,对照组予艾司奥美拉唑钠注射液40 mg静脉注射,日1次;共10 d,10 d后改口服奥美拉唑肠溶胶囊1粒,日2次,实验组用药同对照组,同时加服七方胃痛方加减1剂,日2次。将1个疗程常规设定为8周,其中6周为用药期,2周为观察期。结果完成1个治疗周期(8周)后,对照组治疗前后的临床症状评分、胃镜征象评分差别均具有统计学意义,P <0.05,而对照组治疗前后胃镜病理评分差别不具备统计学意义,P> 0.05。试验组治疗前后的临床症状评分、胃镜征象评分、胃镜病理评分差别均具有统计学意义,P <0.05。同时,试验组治疗后和对照组治疗后的临床症状评分、胃镜征象评分、胃镜病理评分差别均具有统计学意义,P <0.05。结论七方胃痛方加减结合西医常规治疗能改善慢性胃炎伴肠上皮化生患者的临床症状,减轻胃黏膜病变。

Amyloid beta-peptide worsens cognitive impairment following cerebral ischemia-reperfusion injury

Amyloid 13-peptide, a major component of senile plaques in Alzheimer＇s disease, has been implicated in neuronal cell death and cognitive impairment. Recently, studies have shown that the pathogenesis of cerebral ischemia is closely linked with Alzheimer＇s disease. In this study, a rat model of global cerebral ischemia-reperfusion injury was established via occlusion of four arteries; meanwhile, fibrillar amyloid [3-peptide was injected into the rat lateral ventricle. The Morris water maze test and histological staining revealed that administration of amyloid 13-peptide could further aggravate impairments to learning and memory and neuronal cell death in the hippocampus of rats subjected to cerebral ischemia-reperfusion injury. Western blot showed that phosphorylation of tau protein and the activity of glycogen synthase kinase 313 were significantly stronger in cerebral ischemia-reperfusion injury rats subjected to amyloid [3-peptide administration than those undergo- ing cerebral ischemia-repetfusion or amyloid 13-peptide administration alone. Conversely, the activ- ity of protein phosphatase 2A was remarkably reduced in rats with cerebral ischemia-reperfusion injury following amyloid 13-peptide administration. These findings suggest that amyloid 13-peptide can potentiate tau phosphorylation induced by cerebral ischemia-reperfusion and thereby aggravate cognitive impairment.

预处理混凝剂对高盐矿井水膜浓缩的影响

模拟混凝预处理后的高盐矿井水及多级反渗透浓水,进行高盐矿井水多级反渗透的膜分离性能试验,采用单因素试验分别研究了矿井水混凝沉淀预处理后可能过量的PAC、PAM对膜通量及脱盐率的影响。结果表明,进水中30 mg/L PAC、0.3 mg/L PAM对一级膜浓缩无显著影响;二级膜浓缩时18 h后150 mg/L PAC与1.5 mg/L PAM作用下膜通量分别下降至新膜通量的70%和46%;三级膜浓缩18 h后750 mg/L PAC和7.5mg/L PAM作用下膜通量分别下降至新膜通量的61%和35%。三级膜浓缩中PAC和PAM膜污染经NaOH清洗后可使膜通量恢复92%和77%。随着过滤时间的增加,脱盐率呈现上升趋势,且PAM对脱盐率的影响大于PAC。

基于双向同步A*算法的AGV路径规划仿真研究

目的解决A^*算法在搜寻过程中查询的节点非常多、耗时较多等问题。方法通过对传统A*算法进行改进,得到改进双向同步A*算法,使算法从起点和终点同时搜索路径,并且对启发函数进行改进。为验证改进算法效果,以仓储AGV为例进行二维与三维仿真。结果改进双向同步A*算法在不同的地图下,耗时分别减少了39.1%,34.3%,34.6%,搜索节点最多减少了140,路径长度基本一致。结论改进双向同步A*算法较传统A^*算法能够更加高效地规划出最优路径,兼顾路径最优和出行复杂度低,提高了检索效率,能够有效解决查询节点多、耗时多等问题。

Phosphorylation of tau protein over time in rats subjected to transient brain ischemia

Transient brain ischemia has been shown to induce hyperphosphorylation of the micro- tubule-associated protein tau. To further determine the mechanisms underlying these processes, we investigated the interaction between tau, glycogen synthase kinase （GSK）-313 and protein phos- phatase 2A. The results confirmed that tau protein was dephosphorylated during brain ischemia; in addition, the activity of GSK-3β was increased and the activity of protein phosphatase 2A was de- creased. After reperfusion, tau protein was hyperphosphorylated, the activity of GSK-3β was de- creased and the activity of protein phosphatase 2A remained low. Importantly, the interaction of tau with GSK-3β and protein phosphatase 2A was altered during ischemia and reperfusion. Lithium chloride could affect tau phosphorylation by regulating the interaction of tau with GSK-3β and pro- tein phosphatase 2A, and improve learning and memory ability of rats after transient brain ischemia. The present study demonstrated that it was the interaction of tau with GSK-3β and protein phos- phatase 2A, rather than their individual activities, that dominates the phosphorylation of tau in tran- sient brain ischemia. Hyperphosphorylated tau protein may play an important role in the evolution of brain injury in ischemic stroke. The neuroprotective effects of lithium chloride partly depend on the inhibition of tau phosphorylation during transient brain ischemia.

A wearable real-time telemonitoring electrocardiogram device compared with traditional Holter monitoring

Arrhythmias are very common in the healthy populations as well as patients with cardiovascular diseases.Among them,atrial fibrillation(AF)and malignant ventricular arrhythmias are usually associated with some clinical events.Early diagnosis of arrhythmias,particularly AF and ventricular arrhythmias,is very important for the treatment and prognosis of patients.Holter is a gold standard commonly recommended for noninvasive detection of paroxysmal arrhythmia.However,it has some shortcomings such as fixed detection timings,delayed report and inability of remote real-time detection.To deal with such problems,we designed and applied a new wearable 72-hour triple-lead H3-electrocardiogram(ECG)device with a remote cloud-based ECG platform and an expertsupporting system.In this study,31 patients were recruited and 24-hour synchronous ECG data by H3-ECG and Holter were recorded.In the H3-ECG group,ECG signals were transmitted using remote real-time modes,and confirmed reports were made by doctors in the remote expert-supporting system,while the traditional modes and detection systems were used in the Holter group.The results showed no significant differences between the two groups in 24-hour total heart rate(HR),averaged HR,maximum HR,minimum HR,premature atrial complexes(PACs)and premature ventricular complexes(PVCs)(P>0.05).The sensitivity and specificity of capture and remote automatic cardiac events detection of PACs,PVCs,and AF by H3-ECG were 93%and 99%,98%and 99%,94%and 98%,respectively.Therefore,the long-term limb triple-lead H3-ECG device can be utilized for domiciliary ECG self-monitoring and remote management of patients with common arrhythmia under medical supervision.

Occludin and connexin 43 expression contribute to the pathogenesis of traumatic brain edema

The experimental model of traumatic brain injury was established in Sprague-Dawley rats according to Feeney＇s free falling method. The brains were harvested at 2, 6 and 24 hours, and at 3 and 5 days after injury. Changes in brain water content were determined using the wet and dry weights. Our results showed that water content of tissue significantly increased after traumatic brain injury, and reached minimum at 24 hours. Hematoxylin-eosin staining revealed pathological impairment of brain tissue at each time point after injury, particularly at 3 days, with nerve cell edema, degenera- tion, and necrosis observed, and the apoptotic rate significantly increased. Immunohistochemistry and western blot analysis revealed that the expression of occludin at the injured site gradually de- creased as injury time advanced and reached a minimum at 3 days after injury; the expression of connexin 43 gradually increased as injury time advanced and reached a peak at 24 hours after in-jury. The experimental findings indicate that changes in occludin and connexin 43 expression were consistent with the development of brain edema, and may reflect the pathogenesis of brain injury.

Effects of group reminiscence on elderly depression: A meta-analysis

Background/purpose:The present meta-analysis was performed to evaluate the effectiveness of group reminiscence on depression in elderly patients.Methods:Published and unpublished randomised controlled trials that assessed the effects of group reminiscence on depression in elderly patients were systematically reviewed using multiple electronic databases.Relative risks for dichotomous data and weighted mean differences for continuous data were calculated with 95%confidence intervals.Results:Ten trials were evaluated.Group reminiscence provided significantly greater relief of depressive symptoms than did the control intervention immediately after and 3 months after the intervention(p<0.00001).However,this advantage disappeared 6 months after the intervention(p?0.14).Group reminiscence significantly improved self-esteem and life satisfaction(p<0.01).Conclusion:Group reminiscence was associated with short-term depression relief among elderly patients with depression and effectively improved self-esteem and life satisfaction.Higher-quality large-scale randomised controlled trials are needed to confirm these findings.

Effects of ulinastatin on immune function, oxidative stress and related factors in patients with acute pancreatitis

Objective: To investigate the effects of ulinastatin on immune function, oxidative stress and related factors in patients with acute pancreatitis. Methods: 120 patients with acute pancreatitis admitted to digestive department of our hospital from May 2016 to May 2018 were randomly divided into control group and observation group, 60 cases in each group. Patients in the control group were given routine treatment, while patients in the observation group were given ulinastatin on the basis of the treatment of patients in the control group. The levels of Kim-1, Cys C, BUN, IgA, IgM, IgG, SOD, NO, TAC, PCT and CRP of patients in the two groups were detected and compared before and after treatment. Results: After treatment, the serum levels of Kim-1, Cys C, BUN, NO, PCT and CRP of patients in the control group and the observation group decreased significantly and the serum levels of IgA, IgG, IgM, SOD and TAC increased significantly. The change trend of these indexes in the serum of patients in the observation group was more obvious than those of patients in the control group (P<0.05). Conclusion: Ulinastatin in the treatment of acute pancreatitis can significantly alleviate kidney injury, enhance immune function and antioxidant capacity of patients, alleviate inflammation.

基于有限元的飞轮电池转子系统振动分析与结构优化

由于飞轮电池最大储能密度与转子转速成二次方关系,且飞轮电池转子高速旋转时受不平衡力和陀螺效应影响,会产生复杂的动力学行为。本文对飞轮电池进行振动分析和结构优化。利用CATIA软件对飞轮电池转子进行三维建模。将磁轴承简化为弹性支撑,在Workbench软件中进行模态分析。基于不平衡力影响,在转轴末端施加不平衡力进行谐响应分析,验证了模态分析的仿真结果。以降低转子表面最大变形量为目标,在Workbench中使用响应曲面优化分析工具,对转子外环的宽度和高度,轮毂的宽度和半径进行优化设计。通过仿真验证优化飞轮电池转子结构使得其储能能力显著提高。

Epigenetic control on cell fate choice in neural stem cells

Derived from neural stem cells(NSCs)and progenitor cells originated from the neuroectoderm,the nervous system presents an unprecedented degree of cellular diversity,interwoven to ensure correct connections for propagating information and responding to environ-mental cues.NSCs and progenitor cells must integrate cell-intrinsic programs and environmental cues to achieve production of appropriate types of neurons and glia at appropriate times and places during develop-ment.These developmental dynamics are reflected in changes in gene expression,which is regulated by transcription factors and at the epigenetic level.From early commitment of neural lineage to functional plas-ticity in terminal differentiated neurons,epigenetic regulation is involved in every step of neural develop-ment.Here we focus on the recent advance in our un-derstanding of epigenetic regulation on orderly genera-tion of diverse neural cell types in the mammalian nervous system,an important aspect of neural devel-opment and regenerative medicine.

NONO Regulates Cortical Neuronal Migration and Postnatal Neuronal Maturation

Dear Editor,The mammalian cerebral cortex,responsible for all higherorder brain functions,is organized into six layers of neurons that form distinct projections and connections within and outside the cortex.During cortical development,neural progenitor cells(NPCs)in the proliferative ventricular zone(VZ)and subventricular zone(SVZ)of the dorsal telencephalon produce projection neurons that migrate toward the pial surface to form the cortical plate(CP).

STAT3 signal that mediates the neural plasticity is involved in willed-movement training in focal ischemic rats

Willed-movement training has been demonstrated to be a promising approach to increase motor per- formance and neural plasticity in ischemic rats. However, little is known regarding the molecular signals that are in- volved in neural plasticity following willed-movement training. To investigate the potential signals related to neural plasticity following willed-movement training, littermate rats were randomly assigned into three groups： middle cerebral artery occlusion, environmental modification, and willed-movement training. The infarct volume was measured 18 d after occlusion of the right middle cerebral artery. Reverse transcription-polymerase chain reaction （PCR） and im- munofluorescence staining were used to detect the changes in the signal transducer and activator of transcription 3 （STAT3） mRNA and protein, respectively. A chromatin immunoprecipitation was used to investigate whether STAT3 bound to plasticity-related genes, such as brain-derived neurotrophic factor （BDNF）, synaptophysin, and protein in- teracting with C kinase 1 （PICK1）. In this study, we demonstrated that STAT3 mRNA and protein were markedly increased following 15-d willed-movement training in the ischemic hemispheres of the treated rats. STAT3 bound to BDNF, PICK1, and synaptophysin promoters in the neocortical cells of rats. These data suggest that the increased STAT3 levels after willed-movement training might play critical roles in the neural plasticity by directly regulating plasticity-related genes.