面向集成电路先进制程的二维信息材料与器件

随着集成电路技术的发展至3 nm节点,摩尔定律接近其物理极限,传统芯片制程面临材料到器件的理论和技术瓶颈。二维信息材料凭借原子层厚度、低功耗等特性被产业界认为是1 nm及以下节点的核心材料,将助力芯片制程延续摩尔定律以及平面到三维的发展,与我国集成电路先进制程长期规划紧密相关。基于国家自然科学基金委员会第343期双清论坛,本文从材料—器件—异质集成多层次回顾了二维信息材料与器件的发展历史,总结了领域内所面临挑战,凝炼了未来5~10年的重大关键科学以及亟需布局的研究方向,进一步提出顶层设计的前沿研究方向和科学基金资助战略。

基于窗口注意力聚合Swin Transformer的无人机影像语义分割方法

采用无人机遥感影像进行地物分类的过程中,由于无人机影像的小尺寸地物目标不够突出和无人机影像背景复杂、地物信息难以辨别等问题,采用现行的经典语义分割方法难以获得理想的地物分类效果。该研究以Swin Transformer网络模型为基础,提出了基于窗口注意力聚合Swin Transformer(window attention aggregation Swin Transformer,WAA SwinT)的语义分割网络模型方法。采用了多窗口注意力聚合的方式来进行更精准的注意力计算,以提升无人机遥感影像中的小尺寸地物目标的分类精度和质量。同时借鉴嵌入连接的思想,采用多级特征嵌入连接解码器改善网络结构,应用于无人机遥感影像的分割中,取得了更精细化的分割效果。为了验证提出的方法在无人机影像语义分割中的效果,分别在城市无人机遥感影像UAVid数据集和UDD数据集进行了实验,并与现行的经典语义分割方法进行了对比。实验结果表明,语义分割方法在UAVid数据集和UDD数据集上均可以得到最佳的语义分割效果。同时,该语义分割方法能显著地提升无人机影像中小尺寸地物精准分割的质量。

正弦交流电絮凝处理含锌电镀废水的研究

[目的]电镀废水中的Zn^(2+)污染控制是当前重要的工业水环境技术问题。[方法]采用正弦交流电絮凝技术和自制的电絮凝装置从废水中除去Zn^(2+)。采用数值模拟的研究方法对电絮凝装置进行了流场分析,并通过实验研究了溶液初始pH、电流密度、初始锌离子浓度、反应时间等因素对去除Zn^(2+)的影响,使用响应面优化方案的Box-Behnken设计获得Zn^(2+)最高去除效率的最佳工艺参数。[结果]钛篮孔板大于3层有利于实现电絮凝装置流场均匀分布;在pH=9、含120 mg/dm^(3)Zn^(2+)的模拟废水溶液中,施加电流密度为0.31 A/m2、频率为50 Hz正弦交流电,通电21.3 min,Zn^(2+)的去除率可达到98.80%。[结论]响应面优化可用于正弦交流电絮凝处理含Zn^(2+)废水的过程。

Morphological disruption and visual tuning alterations in the primary visual cortex in glaucoma(DBA/2J)mice

Glaucoma is a leading cause of irreve rsible blindness wo rldwide,and previous studies have shown that,in addition to affecting the eyes,it also causes abnormalities in the brain.However,it is not yet clear how the primary visual cortex(V1)is altered in glaucoma.This study used DBA/2J mice as a model for spontaneous secondary glaucoma.The aim of the study was to compare the electrophysiological and histomorphological chara cteristics of neurons in the V1between 9-month-old DBA/2J mice and age-matched C57BL/6J mice.We conducted single-unit recordings in the V1 of light-anesthetized mice to measure the visually induced responses,including single-unit spiking and gamma band oscillations.The morphology of layerⅡ/Ⅲneurons was determined by neuronal nuclear antigen staining and Nissl staining of brain tissue sections.Eighty-seven neurons from eight DBA/2J mice and eighty-one neurons from eight C57BL/6J mice were examined.Compared with the C57BL/6J group,V1 neurons in the DBA/2J group exhibited weaker visual tuning and impaired spatial summation.Moreove r,fewer neuro ns were observed in the V1 of DBA/2J mice compared with C57BL/6J mice.These findings suggest that DBA/2J mice have fewer neurons in the VI compared with C57BL/6J mice,and that these neurons have impaired visual tuning.Our findings provide a better understanding of the pathological changes that occur in V1 neuron function and morphology in the DBA/2J mouse model.This study might offer some innovative perspectives regarding the treatment of glaucoma.

大型船舶制造涂装废气治理组合工艺和装备设计

[目的]大型船舶制造涂装废气成分复杂、污染物浓度高、排放风量大,同时含有漆雾、粉尘和挥发性有机物(VOCs)。[方法]根据大型船舶制造涂装废气的排放特征,提出了一套“分级分质漆雾净化+沸石分子筛转筒+蓄热式热力氧化”的组合式治理工艺,分别阐述了各主要部分的设计原理、结构组成、关键参数和工程应用。[结果]该工艺可实现涂装废气中污染物的高效分离净化,废气在处理后能连续稳定地达到排放标准。[结论]单一处理方法无法实现大型船舶制造涂装废气的有效治理,经济高效的组合工艺和装备可有效降低处理成本,提高治理效率。

正弦交流电芬顿法去除废水中四环素的试验研究

正弦交流电芬顿法(SAEF)是一种新型的电芬顿技术。为了探讨SAEF去除废水中四环素(TC)的效能和机理,分别考察了电流密度、初始pH值、电导率和H_(2)O_(2)投加量等参数对TC废水处理效果的影响;探究了SAEF处理TC废水的氧化降解过程和动力学机制。结果表明:使用SAEF对初始质量浓度为100 mg/L的TC废水进行处理,在电流密度为0.694 mA/cm^(2),电导率为1075μS/cm,30%H_(2)O_(2)投加量为1.17 mL/L,初始pH值为3.0,反应时间为120 min的条件下,TC和COD去除率分别达94.87%和82.42%。SAEF处理过程中,TC的共轭结构首先被破坏,生成中间产物,最终被转变为无机物,在最优条件下的TC降解过程遵循二级动力学模型。

Global-local combined features to detect pain intensity from facial expression images with attention mechanism

The estimation of pain intensity is critical for medical diagnosis and treatment of patients.With the development of image monitoring technology and artificial intelligence,automatic pain assessment based on facial expression and behavioral analysis shows a potential value in clinical applications.This paper reports a framework of convolutional neural network with global and local attention mechanism(GLA-CNN)for the effective detection of pain intensity at four-level thresholds using facial expression images.GLA-CNN includes two modules,namely global attention network(GANet)and local attention network(LANet).LANet is responsible for extracting representative local patch features of faces,while GANet extracts whole facial features to compensate for the ignored correlative features between patches.In the end,the global correlational and local subtle features are fused for the final estimation of pain intensity.Experiments under the UNBC-McMaster Shoulder Pain database demonstrate that GLA-CNN outperforms other state-of-the-art methods.Additionally,a visualization analysis is conducted to present the feature map of GLA-CNN,intuitively showing that it can extract not only local pain features but also global correlative facial ones.Our study demonstrates that pain assessment based on facial expression is a non-invasive and feasible method,and can be employed as an auxiliary pain assessment tool in clinical practice.

基于融合式PC-ORB的异源图像配准算法

异源图像配准中,由于图像的成像机理差异,图像像素强度关联和旋转畸变是不可避免的两大问题,针对图像像素强度关联问题,提出了基于辐射不变特征变换(radiation-variation insensitive feature transform,RIFT)的图像配准算法,对图像间像素关联差异小的图像对配准有良好的精度,但对旋转畸变图像会产生较多错误匹配。对于旋转畸变问题,传统的ORB(oriented fast and rotated brief)算法,对旋转图像的配准有一定的稳定性,但对于强度变化不明显的图像对,特征点检测质量较低,配准精度不理想。因此本文将相位一致性(phase consistency,PC)融合进ORB算法,利用相位信息代替传统的图像强度信息,再构造旋转不变性BRIEF特征描述子,对图像像素强度变化和旋转畸变均具有鲁棒性。用图像像素强度关联不明显的红外图像和可见光图像进行配准实验,本文算法针对不同旋转幅度的图像的配准精度较高,RMSE稳定在1.7~2.1,优于RIFT算法,在特征点检测数量、配准精度和效率等性能上均有良好性能。

基于密集残差生成对抗网络的红外图像去模糊

红外图像拍摄过程中,由于摄像设备抖动或目标快速移动会导致图像出现运动模糊,极大影响了有效信息的提取和识别。针对上述问题,本文在DeblurGAN基础上提出一种基于密集残差生成对抗网络的红外图像去模糊方法。该方法首先采用多尺度卷积核,提取红外图像不同尺度和层次的特征。其次,采用密集残差块(residual-in-residual dense block,RRDB)代替原生成网络中的残差单元,改善恢复红外图像的细节信息。通过本课题组自制的红外图像数据集进行实验,结果表明所提出的方法与DeblurGAN相比PSNR提高3.60 dB,SSIM提高0.09,主观视觉去模糊效果较好,恢复后的红外图像边缘轮廓清晰且细节信息明显。

Construction and validation of a neovascular glaucoma nomogram in patients with diabetic retinopathy after pars plana vitrectomy

BACKGROUND Neovascular glaucoma(NVG)is likely to occur after pars plana vitrectomy(PPV)for diabetic retinopathy(DR)in some patients,thus reducing the expected benefit.Understanding the risk factors for NVG occurrence and building effective risk prediction models are currently required for clinical research.AIM To develop a visual risk profile model to explore factors influencing DR after surgery.METHODS We retrospectively selected 151 patients with DR undergoing PPV.The patients were divided into the NVG(NVG occurrence)and No-NVG(No NVG occurrence)groups according to the occurrence of NVG within 6 months after surgery.Independent risk factors for postoperative NVG were screened by logistic regression.A nomogram prediction model was established using R software,and the model’s prediction accuracy was verified internally and externally,involving the receiver operator characteristic curve and correction curve.RESULTS After importing the data into a logistic regression model,we concluded that a posterior capsular defect,preoperative vascular endothelial growth factor≥302.90 pg/mL,glycosylated hemoglobin≥9.05%,aqueous fluid interleukin 6(IL-6)≥53.27 pg/mL,and aqueous fluid IL-10≥9.11 pg/mL were independent risk factors for postoperative NVG in patients with DR(P<0.05).A nomogram model was established based on the aforementioned independent risk factors,and a computer simulation repeated sampling method was used to internally and externally verify the nomogram model.The area under the curve(AUC),sensitivity,and specificity of the model were 0.962[95%confidence interval(95%CI):0.932-0.991],91.5%,and 82.3%,respectively.The AUC,sensitivity,and specificity of the external validation were 0.878(95%CI:0.746-0.982),66.7%,and 95.7%,respectively.CONCLUSION A nomogram constructed based on the risk factors for postoperative NVG in patients with DR has a high prediction accuracy.This study can help formulate relevant preventive and treatment measures.

Study on physical and mechanical properties of cement asphalt emulsified mortar under track slab

Purpose–During the construction process of the China Railway Track System(CRTS)I type filling layer,the nonwoven fabric bags have been used as grouting templates for cement asphalt(CA)emulsified mortar.The porous structure of nonwoven fabrics endowed the templates with breathability and water permeability.The standard requires that the volume expansion rate of CA mortar must be controlled within 1%–3%,which can generate expansion pressure to ensure that the cavities under track slabs are filled fully.However,the expansion pressure caused some of the water to seep out from the periphery of the filling bag,and it would affect the actual mix proportion of CA mortar.The differences in physical and mechanical properties between the CA mortar under track slabs and the CA mortar formed in the laboratory were studied in this paper.The relevant results could provide important methods for the research of filling layer materials for CRTS I type and other types of ballastless tracks in China.Design/methodology/approach–During the inspection of filling layer,the samples of CA mortar from different working conditions and raw materials were taken by uncovering the track slabs and drilling cores.The physical and mechanical properties of CA mortar under the filling layer of the slab were systematically analyzed by testing the electrical flux,compressive strength and density of mortar in different parts of the filling layer.Findings–In this paper,the electric flux,the physical properties and mechanical properties of different parts of CA mortar under the track slab were investigated.The results showed that the density,electric flux and compressive strength of CA mortar were affected by the composition of raw materials for dry powders and different parts of the filling layer.In addition,the electrical flux of CA mortar gradually decreased within 90 days’age.The electrical flux of samples with the thickness of 54 mm was lower than 500 C.Therefore,the impermeability and durability of CA mortar could be improved by increasing the thickness of filling layer.Besides,the results showed that the compressive strength of CA mortar increased,while the density and electric flux decreased gradually,with the prolongation of hardening time.Originality/value–During 90 days’age,the electrical flux of the CA mortar gradually decreased with the increase of specimen thickness and the electrical flux of the specimens with the thickness of 54 mm was lower than 500 C.The impermeability and durability of the CA mortar could be improved by increasing the thickness of filling layer.The proposed method can provide reference for the further development and improvement of CRTS I and CRTS II type ballastless track in China.

Analysis of Traffic Accidents Based on the Integration Model

To enhance the safety of road traffic operations,this paper proposed a model based on stacking integrated learning utilizing American road traffic accident statistics.Initially,the process involved data cleaning,transformation,and normalization.Subsequently,various classification models were constructed,including logistic regression,k-nearest neighbors,gradient boosting,decision trees,AdaBoost,and extra trees models.Evaluation metrics such as accuracy,precision,recall,F1 score,and Hamming loss were employed.Upon analysis,the passive-aggressive classifier model exhibited superior comprehensive indices compared to other models.Based on the model’s output results,an in-depth examination of the factors influencing traffic accidents was conducted.Additionally,measures and suggestions aimed at reducing the incidence of severe traffic accidents were presented.These findings served as a valuable reference for mitigating the occurrence of traffic accidents.

基于轻量级CNN-Transformer混合网络的梯田图像语义分割

梯田是一种传统的农业种植方式,具有稳定作物生产与水土保持的作用。快速、准确地对梯田区域分布信息进行采集,对提高粮食产量、治理水土流失以及规划区域生态等具有重要的作用与意义。无人机图像梯田道路边界模糊、具有较长的带状结构,为了更准确地获取梯田的边缘信息,受MobileVit启发,该研究在MobileViT block中引入了轴向注意力机制(axial attention),并采用编码器-解码器结构,提出了基于轻量级CNN-Transformer混合构架网络模型。模型编码器部分由改进的MobileViT block、融入了条形池化的逆残差模块和空洞空间金字塔池化模块构成,再通过有效设计摆放各模块的位置顺序来实现局部与全局的视觉表征信息交互,得到完整的全局特征表达;利用解码器对编码器提取到的多尺度特征图进行采样和卷积操作得到语义分割结果图。选取PSPNet、LiteSeg、BisNetv2、Deeplabv3Plus、MobileViT在相同测试集上进行对比试验,结果表明,该研究所提模型在精度与速度方面均具有一定的优势,其像素精度可达95.79%,频权交并比可达94.86%,模型参数量为8.32 M,实现了使用较少的参数和简单的方法对复杂无规则的无人机图像梯田区域较为准确的分割,将其部署到无人机上可以进一步获取梯田的形状、位置、轮廓等信息,可为预防和修护加固梯田提供重要的依据,同时有助于梯田区域种植面积和范围的统计,为梯田和旱作区农业建设的发展提供参考。

涂装废气漆雾分离的流场模拟与试验研究

在处理含有大量漆雾、挥发性有机物等有害物质的喷漆废气时,干式过滤法与湿式净化技术相比更经济有效,但容易产生堵塞问题。本文分析了漆雾的特性及干式过滤器堵塞的机理,提出了拦截-过滤耦合工艺和自制了实验装置。首先采用流体动力学的计算方法建立数值模型,优化了折流板拦截装置的结构和运行参数。数值模拟研究的结果表明:在板间距20 mm、折角90°、入口气流速度8 m/s的条件下,折流板拦截装置的压降为220.2 Pa,对直径15μm的漆雾的分离效率为84.7%。在上述优化条件下进行了试验验证,实测折流板拦截装置的压降和漆雾分离效率分别为303.3Pa和78.34%,整个拦截-过滤耦合装置的漆雾分离效率达到96.38%。

Remodeling the tumor immune microenvironment via siRNA therapy for precision cancer treatment

How to effectively transform the pro-oncogenic tumor microenvironments(TME)surrounding a tumor into an anti-tumoral never fails to attract people to study.Small interfering RNA(siRNA)is considered one of the most noteworthy research directions that can regulate gene expression following a process known as RNA interference(RNAi).The research about siRNA delivery targeting tumor cells and TME has been on the rise in recent years.Using siRNA drugs to silence critical proteins in TME was one of the most efficient solutions.However,the manufacture of a siRNA delivery system faces three major obstacles,i.e.,appropriate cargo protection,accurately targeted delivery,and site-specific cargo release.In the following review,we summarized the pharmacological actions of siRNA drugs in remolding TME.In addition,the delivery strategies of siRNA drugs and combination therapy with siRNA drugs to remodel TME are thoroughly discussed.In the meanwhile,the most recent advancements in the development of all clinically investigated and commercialized siRNA delivery technologies are also presented.Ultimately,we propose that nanoparticle drug delivery siRNA may be the future research focus of oncogene therapy.This summary offers a thorough analysis and roadmap for general readers working in the field.

Supplementation with yak (Bos grunniens) bone collagen hydrolysate altered the structure of gut microbiota and elevated short-chain fatty acid production in mice

In this study, yak bone collagen hydrolysate(YBCH)was produced by mixed proteases and provided to standard-diet mice at a different dose(low dose(LD), medium dose(MD), and high dose(HD))to investigate its effects on the composition of gut microbiota and short-chain fatty acids(SCFA)production. It was found that YBCH was mainly composed of small molecular peptides whose molecular weight below 2 000 Da. Notably, supplementation with different doses of YBCH could significantly downregulate the ratio of Firmicutes to Bacteroidetes in the fecal microbiota. At the family level, the Lachnospiraceae abundance was significantly reduced in the YBCH gavage groups(mean reduction ratio 41.7 %, 35.2%, and 36.4% for LD, MD, and HD group, respectively). The predicted functions of gut microbes in the MD group were significantly increased at “lipid metabolism” and “glycan biosynthesis and metabolism”. Moreover, the SCFA production in the YBCH groups was elevated. Especially, the concentration of acetic acid, propionic acid, and butyric acid in the MD group was separately increased 79.7%, 89.2%, and 78.8% than that in the NC group. These results indicated that YBCH might be applied in the development of functional food for intestinal microecological regulation.

Medical Journals in China: From Wuyi Huijiang to Chinese Medical Journal and hLife

As Professor Jiaxi Lu,the former president of the Chinese Academy of Sciences(CAS),said,“Academic journals are both the‘tail’and the‘head’of a dragon”[1].Professor Zuoyan Zhu,former editor-in-chief of both Science China and Science Bulletin,also once said,“Let Chinese scientific journals grow along with scientific research in China”[2].Academic journals are important carriers for the exchange and dissemination of innovation and achievement in science and are important gardens for the training of scientific talent;also,they play an important role in carrying out an evaluation of academic work.Medical journals are an important component of the academic journal sphere,not only because they account for onethird of academic journals but also because they are directly related to human health。

Intrinsic Electronic Properties of BN-Encapsulated,van der Waals Contacted MoSe_(2)Field-Effect Transistors

Two-dimensional(2D)semiconductors have attracted considerable interest for their unique physical properties.Here,we report the intrinsic cryogenic electronic transport properties in few-layer MoSe_(2)field-effect transistors(FETs)that are fully encapsulated in ultraclean hexagonal boron nitride dielectrics and are simultaneously van der Waals contacted with gold electrodes.The FETs exhibit electronically favorable channel/dielectric interfaces with low densities of interfacial traps(<1010cm^(-2)),which lead to outstanding device characteristics at room temperature,including near-Boltzmann-limit subthreshold swings(65 mV/dec),high carrier mobilities(53–68 cm^(2)·V-1·s^(-1)),and negligible scanning hystereses(<15 mV).The dependence of various contact-related parameters with temperature and carrier density is also systematically characterized to understand the van der Waals contacts between gold and MoSe_(2).The results provide insightful information about the device physics in van der Waals contacted and encapsulated 2D FETs.

Self-Oscillated Growth Formation of Standing Ultrathin Nanosheets out of Uniform Ge/Si Superlattice Nanowires

Self-oscillation is an intriguing and omnipresent phenomenon that governs a broad range of growth dynamics and formation of nanoscale periodic and delicate heterostructures.A self-oscillating growth phenomenon of catalyst droplets,consuming surface-coating a-Si/a-Ge bilayer,is exploited to accomplish a high-frequency alternating growth of ultrathin crystalline Si and Ge(c-Si/c-Ge)nano-slates,with Ge-rich layer thickness of 14–19 nm,embedded within a superlattice nanowire structure,with pre-known position and uniform channel diameter.A subsequent selective etching of the Ge-rich segments leaves a chain of ultrafine standing c-Si nanosheets down to~6 nm thick,without the use of any expensive high-resolution lithography and growth modulation control.A ternary-phase-competition model has been established to explain the underlying formation mechanism of this nanoscale self-oscillating growth dynamics.It is also suggested that these ultrathin nanosheets could help to produce ultrathin fin-channels for advanced electronics,or provide size-specified trapping sites to capture and position hetero nanoparticle for high-precision labelling or light emission.

Enhancement of Carrier Mobility in Semiconductor Nanostructures by Carrier Distribution Engineering

Two-dimensional(2D)van der Waals semiconductors are appealing for low-power transistors.Here,we show the feasibility in enhancing carrier mobility in 2D semiconductors through engineering the vertical distribution of carriers confined inside ultrathin channels via symmetrizing gate configuration or increasing channel thickness.Through self-consistently solving the Schr¨odinger–Poisson equations,the shapes of electron envelope functions are extensively investigated by clarifying their relationship with gate configuration,channel thickness,dielectric permittivity,and electron density.The impacts of electron distribution variation on various carrier scattering matrix elements and overall carrier mobility are insightfully clarified.It is found that the carrier mobility can be generally enhanced in the dual-gated configuration due to the centralization of carrier redistribution in the nanometer-thick semiconductor channels and the rate of increase reaches up to 23%in Hf O2 dual-gated 10-layer MoS_(2) channels.This finding represents a viable strategy for performance optimization in transistors consisting of 2D semiconductors.