整车环境对天线性能影响的研究

汽车的智能化和网联化对车载天线的性能提出了更高的要求。传统测试方法仅仅是在微波暗室内检测天线单体的性能,并没有考虑天线装车后汽车周边电磁环境、车身结构、安装位置等因素,因此,并不能直观准确的反映整车级天线性能。文章利用仿真和整车OTA暗室等手段,对车载天线性能进行测试。研究发现,电磁环境、车身结构、安装位置等因素均对整车级天线性能有较大影响。此研究结果对车载天线设计和安装有一定指导意义。

Wrecking neutrophil extracellular traps and antagonizing cancer-associated neurotransmitters by interpenetrating network hydrogels prevent postsurgical cancer relapse and metastases

Tumor-promoting niche after incomplete surgery resection(SR)can lead to more aggressive local progression and distant metastasis with augmented angiogenesis-immunosuppressive tumor microenvironment(TME).Herein,elevated neutrophil extracellular traps(NETs)and cancer-associated neurotransmitters(CANTs,e.g.,catecholamines)are firstly identified as two of the dominant inducements.Further,an injectable fibrin-alginate hydrogel with high tissue adhesion has been constructed to specifically co-deliver NETs inhibitor(DNase I)-encapsulated PLGA nanoparticles and an unselectiveβ-adrenergic receptor blocker(propranolol).The two components(i.e.,fibrin and alginate)can respond to two triggers(thrombin and Ca2+,respectively)in postoperative bleeding to gelate,shaping into an interpenetrating network(IPN)featuring high strength.The continuous release of DNase I and PR can wreck NETs and antagonize catecholamines to decrease microvessel density,blockade myeloid-derived suppressor cells,secrete various proinflammatory cytokines,potentiate natural killer cell function and hamper cytotoxic T cell exhaustion.The reprogrammed TME significantly suppress locally residual and distant tumors,induce strong immune memory effects and thus inhibit lung metastasis.Thus,targetedly degrading NETs and blocking CANTs enabled by this in-situ IPN-based hydrogel drug depot provides a simple and efficient approach against SR-induced cancer recurrence and metastasis.

Initial therapeutic evidence of a borosilicate bioactive glass(BSG)and Fe_(3)O_(4)magnetic nanoparticle scaffold on implant-associated Staphylococcal aureus bone infection

Implant-associated Staphylococcus aureus(S.aureus)osteomyelitis is a severe challenge in orthopedics.While antibiotic-loaded bone cement is a standardized therapeutic approach for S.aureus osteomyelitis,it falls short in eradicating Staphylococcus abscess communities(SACs)and bacteria within osteocyte-lacuna canalicular network(OLCN)and repairing bone defects.To address limitations,we developed a borosilicate bioactive glass(BSG)combined with ferroferric oxide(Fe_(3)O_(4))magnetic scaffold to enhance antibacterial efficacy and bone repair capabilities.We conducted comprehensive assessments of the osteoinductive,immunomodulatory,antibacterial properties,and thermal response of this scaffold,with or without an alternating magnetic field(AMF).Utilizing a well-established implant-related S.aureus tibial infection rabbit model,we evaluated its antibacterial performance in vivo.RNA transcriptome sequencing demonstrated that BSG+5%Fe_(3)O_(4)enhanced the immune response to bacteria and promoted osteogenic differentiation and mineralization of MSCs.Notably,BSG+5%Fe_(3)O_(4)upregulated gene expression of NOD-like receptor and TNF pathway in MSCs,alongside increased the expression of osteogenic factors(RUNX2,ALP and OCN)in vitro.Flow cytometry on macrophage exhibited a polarization effect towards M2,accompanied by upregulation of anti-inflammatory genes(TGF-β1 and IL-1Ra)and downregulation of pro-inflammatory genes(IL-6 and IL-1β)among macrophages.In vivo CT imaging revealed the absence of osteolysis and periosteal response in rabbits treated with BSG+5%Fe_(3)O_(4)+AMF at 42 days.Histological analysis indicated complete controls of SACs and bacteria within OLCN by day 42,along with new bone formation,signifying effective control of S.aureus osteomyelitis.Further investigations will focus on the in vivo biosafety and biological mechanism of this scaffold within infectious microenvironment.

An aqueous magnesium-ion hybrid supercapacitor operated at-50℃

The recent advances in aqueous magnesium-ion hybrid supercapacitor(MHSC)have attracted great attention as it brings together the benefits of high energy density,high power density,and synchronously addresses cost and safety issues.However,the freeze of aqueous electrolytes discourages aqueous MHSC from operating at low-temperature conditions.Here,a low-concentration aqueous solution of 4 mol L^(-1) Mg(ClO_(4))_(2) is devised for its low freezing point(-67℃)and ultra-high ionic conductivity(3.37 mS cm^(-1) at-50℃).Both physical characterizations and computational simulations revealed that the Mg(ClO_(4))_(2) can effectively disrupt the original hydrogen bond network among water molecules via transmuting the electrolyte structure,thus yielding a low freezing point.Thus,the Mg(ClO_(4))_(2) electrolytes endue aqueous MHSC with a wider temperature operation range(-50℃–25℃)and a higher energy density of 103.9 Wh kg^(-1) at 3.68 kW kg^(-1) over commonly used magnesium salts(i.e.,MgSO_(4) and Mg(NO_(3))_(2))electrolytes.Furthermore,a quasi-solid-state MHSC based on polyacrylamide-based hydrogel electrolyte holds superior low-temperature performance,excellentflexibility,and high safety.This work pioneers a convenient,cheap,and eco-friendly tactic to procure low-temperature aqueous magnesium-ion energy storage device.

考虑信息时移的分布式光伏接入配电网功率预测方法

为了降低分布式光伏接入配电网功率预测值误差,提出考虑信息时移的分布式光伏接入配电网功率预测方法。采用皮尔逊相关系数描述数值天气预报(NWP)关键气象因子、光伏输出功率间的关联关系,确定最佳时移量,修正地理位置引起的气象信息偏移;采用随机森林算法处理分布式光伏出力数据,筛选高贡献度特征参数;利用双向门控循环控制单元(GRU)神经网络学习特征参数后,通过一维卷积神经网络捕捉输入时间序列的各个时间步;引入注意力机制降低气象时移量对分布式光伏出力的影响,实现功率预测结果的输出。试验结果表明:该方法可计算分布式光伏出力与气象数据间的皮尔逊相关系数,确定其最佳时移量;不同气象条件下预测值与实际值间误差均较小。

整车空口天线测试技术的发展趋势

智能网联汽车集成了各种智能感知系统,车载天线通信性能的评估普遍应用空口(OTA)测试技术。文章阐述了OTA测试标准现状、整车OTA测试面临的挑战,介绍了整车天线测试的直接远场法、紧缩场法、近场转换结合远场法各自的特点,分别测试了车载天线无源指标以及手机和整车的有源发射指标。从测试原理、测试方案、工程实践等方面阐述了汽车OTA测试技术的发展趋势。

2,2′,4,4′-四溴联苯醚对斑马鱼胚胎生长发育的影响研究

为探究2,2′,4,4′-四溴联苯醚(BDE-47)对生长发育的影响,以斑马鱼为模型,将发育至受精后4 h(受精后小时数,hours post-fertilization,hpf)的斑马鱼胚胎暴露于0.312~1.25 mg/L BDE-47中,培养至72 hpf,观察胚胎心率和畸变率。测量斑马鱼胚胎胚体长度和卵黄延伸部长度;吖啶橙染色后荧光显微镜分析斑马鱼胚胎细胞凋亡情况;RT-qPCR分析心脏发育、骨骼形态和生长相关基因的表达变化。研究结果显示,BDE-47促使斑马鱼胚胎的心率和畸形率增加,阻滞了胚体和卵黄延伸部发育,致使胚胎细胞凋亡;BDE-47暴露对etv2基因表达无影响,但上调了胚胎早期心肌标志基因gata4的表达,抑制了骨形成蛋白质基因bmp2b的表达,干扰了GH/IGF1/PI3K通路相关基因(gh1、ghra、igf1、pik3ca、pik3r1、akt和mTOR)的表达。这表明,BDE-47对斑马鱼胚胎具有生长发育毒性,其机制与上述基因表达异常有关。

Cerebrovascular segmentation from mesoscopic optical images using Swin Transformer

Vascular segmentation is a crucial task in biomedical image processing,which is significant for analyzing and modeling vascular networks under physiological and pathological states.With advances in fluorescent labeling and mesoscopic optical techniques,it has become possible to map the whole-mouse-brain vascular networks at capillary resolution.However,segmenting vessels from mesoscopic optical images is a challenging task.The problems,such as vascular signal discontinuities,vessel lumens,and background fluorescence signals in mesoscopic optical images,belong to global semantic information during vascular segmentation.Traditional vascular segmentation methods based on convolutional neural networks(CNNs)have been limited by their insufficient receptive fields,making it challenging to capture global semantic information of vessels and resulting in inaccurate segmentation results.Here,we propose SegVesseler,a vascular segmentation method based on Swin Transformer.SegVesseler adopts 3D Swin Transformer blocks to extract global contextual information in 3D images.This approach is able to maintain the connectivity and topology of blood vessels during segmentation.We evaluated the performance of our method on mouse cerebrovascular datasets generated from three different labeling and imaging modalities.The experimental results demonstrate that the segmentation effect of our method is significantly better than traditional CNNs and achieves state-of-the-art performance.

Viscosity reduction of tapioca starch by incorporating with molasses hydrocolloids

As a low cost non-staple food resource,the high-viscosity paste and poor gel-forming ability of tapioca starch limit its industrial application.Herein,molasses hydrocolloids that is a by-product of the sugar refining process was applied as a blending modifier to reduce the viscosity of tapioca starch paste.The test results of paste and rheological properties show that molasses hydrocolloids exhibited a good physical viscosity-reducing effect on tapioca starch paste.The irregular network structure and high K^(+)/Ca^(2+)ion contents of molasses hydrocolloids exerted wrapping,adhesion,barrier,and hydration effects on starch,leading to the reduction of viscosity.The scanning electron microscope images and textural analysis demonstrated that this strategy also improve the structure of tapioca starch gel and enhanced its puncture strength by 75.46%.This work shows the great potential of molasses hydrocolloids as a lowcost and desirable material for the viscosity reduction of tapioca starch.

A review of the etched terminal structure of a 4H-SiC PiN diode

The comparison of domestic and foreign studies has been utilized to extensively employ junction termination extension(JTE)structures for power devices.However,achieving a gradual doping concentration change in the lateral direction is difficult for SiC devices since the diffusion constants of the implanted aluminum ions in SiC are much less than silicon.Many previously reported studies adopted many new structures to solve this problem.Additionally,the JTE structure is strongly sensitive to the ion implantation dose.Thus,GA-JTE,double-zone etched JTE structures,and SM-JTE with modulation spacing were reported to overcome the above shortcomings of the JTE structure and effectively increase the breakdown voltage.They provided a theoretical basis for fabricating terminal structures of 4H-SiC PiN diodes.This paper summarized the effects of different terminal structures on the electrical properties of SiC devices at home and abroad.Presently,the continuous development and breakthrough of terminal technology have significantly improved the breakdown voltage and terminal efficiency of 4H-SiC PiN power diodes.

武夷山平须舞虻属Platypalpus五新种(双翅目:舞虻科)

平须舞虻属Platypalpus Macquart是舞虻科中最大的属之一,已知560余种分布世界各地,我国已知66种。武夷山仅报道1种:弯刺平须舞虻Platypalpus curvispinus Yang&Yang,2003。本文记述武夷山平须舞虻属5新种:叉平须舞虻Platypalpus bifurcates sp.nov.,宽端平须舞虻Platypalpus latiapicatus sp.nov.,宽斑平须舞虻Platypalpus latimaculatus sp.nov.,武夷山平须舞虻Platypalpus wuyishanus sp.nov.,先锋岭平须舞虻Platypalpus xianfenglinganus sp.nov.;并编制了武夷山平须舞虻属的分种检索表。

关于应对疫情开展化学类专业课程线上教学的探究

针对四川大学应对疫情开展的化学类专业线上课程实施情况,探究其更加有效合理的教学组织方式。通过对师生的调研和反馈,提出现阶段线上教学面临的难点与挑战:课堂互动与讨论不流畅、线上教学工具及开展方式繁多、化学实验课程不配套。因此,四川大学化学学院将统筹线上教学平台,增强课堂互动效果,启动“化学虚拟仿真实验教学中心”,保证疫情防控期间的教学进度和质量。

Collagen type Ⅱ suppresses articular chondrocyte hypertrophy and osteoarthritis progression by promoting integrin β1-SMAD1 interaction

Hypertrophic differentiation is not only the terminal process of endochondral ossification in the growth plate but is also an important pathological change in osteoarthritic cartilage.Collagen type II(COL2A1)was previously considered to be only a structural component of the cartilage matrix,but recently,it has been revealed to be an extracellular signaling molecule that can significantly suppress chondrocyte hypertrophy.However,the mechanisms by which COL2A1 regulates hypertrophic differentiation remain unclear.In our study,a Col2a1 p.Gly1170Ser mutant mouse model was constructed,and Col2a1 loss was demonstrated in homozygotes.Loss of Col2a1 was found to accelerate chondrocyte hypertrophy through the bone morphogenetic protein(BMP)-SMAD1 pathway.Upon interacting with COL2A1,integrinβ1(ITGB1),the major receptor for COL2A1,competed with BMP receptors for binding to SMAD1 and then inhibited SMAD1 activation and nuclear import.COL2A1 could also activate ITGB1-induced ERK1/2 phosphorylation and,through ERK1/2-SMAD1 interaction,it further repressed SMAD1 activation,thus inhibiting BMP-SMAD1-mediated chondrocyte hypertrophy.Moreover,COL2A1 expression was downregulated,while chondrocyte hypertrophic markers and BMP-SMAD1 signaling activity were upregulated in degenerative human articular cartilage.Our study reveals novel mechanisms for the inhibition of chondrocyte hypertrophy by COL2A1 and suggests that the degradation and decrease in COL2A1 might initiate and promote osteoarthritis progression.

Magnesium-based biomaterials as emerging agents for bone repair and regeneration:from mechanism to application

Magnesium(Mg)is the fourth most abundant element in the human body and is important in terms of specific osteogenesis functions.Here,we provide a comprehensive review of the use of magnesium-based biomaterials(MBs)in bone reconstruction.We review the history of MBs and their excellent biocompatibility,biodegradability and osteopromotive properties,highlighting them as candidates for a new generation of biodegradable orthopedic implants.In particular,the results reported in the field-specific literature(280 articles)in recent decades are dissected with respect to the extensive variety of MBs for orthopedic applications,including Mg/Mg alloys,bioglasses,bioceramics,and polymer materials.We also summarize the osteogenic mechanism of MBs,including a detailed section on the physiological process,namely,the enhanced osteogenesis,promotion of osteoblast adhesion and motility,immunomodulation,and enhanced angiogenesis.Moreover,the merits and limitations of current bone grafts and substitutes are compared.The objective of this review is to reveal the strong potential of MBs for their use as agents in bone repair and regeneration and to highlight issues that impede their clinical translation.Finally,the development and challenges of MBs for transplanted orthopedic materials are discussed.

Analysis on Factors Related to Rabies Epidemic in China from 2007-2011

To analyze features of the rabies epidemic in China between 2007 and 2011, identify factors influencing the epidemic and to provide a scientific basis for further control and prevention of rabies, Descriptive epidemiological methods and statistical analysis was used on data collected from the National Disease Reporting Information System between 2007 to 2011 and the National Active Surveillance System between 2007 and 2010. Our analysis shows that while the number of human rabies cases decreased year by year, the number of districts reporting cases did not show significant change. The situations in Guangdong, Guangxi, Guizhou and Hunan provinces clearly improved over the period but they remain provinces with high-incidence, and consequently influence the epidemic situation of surrounding provinces and possibly the whole country. Summer and autumn were high-incidence seasons. Farmers, students and pre-school children represent the high-risk populations, and rates of cases in farmers increased, those for students decreased, and pre-school children remained unchanged. Provinces with active surveillance programs reported a total of 2346 individual cases, of which 88.53% were associated with canines. Postexposure prophylaxis （PEP） of rabies cases was not significantly improved, whereas PEP in post-exposure population was good. In rural regions of China, canine density was reduced somewhat, and the immunization rate increased slightly. Finally we show that while the epidemic decreased 2007 to 2011 in China, cases continued to be diffused in certain regions. Lack of standardization of PEP on rabies eases was the main reason of morbidity. The high density and low immunization of dog in rural areas and the defective situation of PEP are still continuous occurrences in China and remain a cause for concern.

Complex variable solution for boundary value problem with X-shaped cavity in plane elasticity and its application*

A new type of displacement pile, the X-section cast-in-place concrete （XCC） pile, has recently been developed in China. Extensive field tests and laboratory experi- ments are undertaken to evaluate its performance and quantify the non-uniform deforma- tion effect （NUDE） of the X-shaped cross section during installation. This paper develops a simplified theoretical model that attempts to capture the NUDE. Based on the theory of complex variable plane elasticity, closed-form solutions of the stress and displacement for the X-shaped cavity boundary value problem are given. Subsequently, the analytical solution is used to evaluate the NUDE, the concrete filling index （CFI）, and the perimeter reduction coefficient of the XCC pile cross section. The computed results are compared with field test results, showing reasonable agreement. The present simplified theoretical model reveals the deformation mechanism of the X-shaped cavity and facilitates applica- tion of the newly developed XCC pile technique in geotechnical engineering.

烯碳材料改性有机高性能纤维:制备、性能及应用

有机高性能纤维是全球化纤工业的重要发展方向之一。提升现有纤维力学性能的同时研发新型结构功能一体化的纤维对提升我国在航天航空等领域的国际地位具有重要意义。以石墨烯和碳纳米管为代表的烯碳材料具备优异的力、电、热学等性能,可用于改性传统有机高性能纤维。通过制备不同物化性质的烯碳材料并设计合理的改性方式,可将烯碳材料优异的性能传递到传统纤维中,形成具备更高力、电、热学等性能的烯碳材料改性有机高性能纤维。本文首先综述了烯碳材料改性有机高性能纤维的制备方式,包括烯碳材料的分散与功能化、烯碳材料对有机高性能纤维的改性方法,阐述了烯碳材料改性有机高性能纤维的力、电、热学等性能以及烯碳材料的增强机理,进而总结了烯碳材料改性有机高性能纤维的应用,并对其现存的挑战和未来的发展做出展望。

A pharmacodynamic model of portal hypertension in isolated perfused rat liver

AIM： To develop a pharmacodynamic model of porta hypertension from chronic hepatitis. METHODS： Pathological changes and collagen depositions were analyzed using morphometry to confirm CCI4-induced chronic hepatitis. At do, d28, ds6 and d84 of the process, the portal perfused velocities （μL/min） in isolated rat livers were exactly controlled with a quanti-fied pump. The pressure （mmHg） was monitored with a Physiological System. The geometric concentrations of phenylephrine or acetylcholine were added to a fixed volume （300 mL） of the circulating perfusate. The equation, the median effective concentration and its 95% confidence intervals of phenylephrine or acetyl- choline were regressed with Prism-4 software in non-linear fit and various slopes. In the isolated perfused rat livers with chronic hepatitis, both median effective concentrations were defined as the pharmacodynamic model of portal hypertension.CONCLUSION： A pharmacodynamic model of portal hypertension in isolated perfused rat livers with chronic hepatitis was defined as the median effective concen- trations of phenylephrine and acetylcholine.

列宁帝国主义论对古典帝国主义理论的批判与超越

列宁在对古典帝国主义理论批判与超越的基础上创立了马克思主义帝国主义理论。从"整体"文本和比较研究出发,列宁帝国主义论对古典帝国主义理论的批判表现在:一是批判霍布森"消费不足论"--消费不足既是生产过剩和资本过剩的原因又是分配不当的结果;二是批判希法亭"一个错误、几个不足"--关于货币的理论错误、金融资本定义的不足、忽视(几乎)世界的瓜分、忽视帝国主义与寄生性、机会主义的关系;三是批判考茨基"帝国主义是什么"和"帝国主义向哪去"--帝国主义定义及其错误根源、超帝国主义及其斗争策略。列宁帝国主义论对古典帝国主义理论的超越体现在:一是观点的超越--科学帝国主义观点体系;二是方法的超越--唯物史观和辩证法;三是立场的超越--无产阶级国际主义立场。

Modeling and Simulation of Adaptive Surface Tracked Vehicle Based on RecurDyn

In order to improve the adaptability of the tracked vehicle in the road and strengthen the grip of the tracked vehicle, a track surface adaptive mechanism was provided. In theory, it has been proved practically. Meanwhile, RecurDyn, which is a multi-body kinematics software, was used to build a multi-body soft hybrid model, based on structure, elasticity, linear damping adaptive tracked vehicle;meanwhile the model was used to carry on the kinematics simulation. Through the comparison between simulated motion trail and that of traditional motion trail, this paper analyzed the deviation of the motion trail and also simulated the motion trail of the warped surface so as to test the adaptive ability of the mechanism. According to the results, the adaptive mechanism was equipped with great surface adaptability. It can also adapt to the complex warped surface, and enjoy a damping effect.