摘要：Objective It has been reported that B-cell lymphoma 2 （Bcl-2） enhances neurogenesis as well as supporting axonal growth after injury. In the present study, we investigated whether Bcl-2 overexpression plays a role in the formation of newborn striatonigral projection neurons in the adult rat brain after transient middle cerebral artery occlusion （MCAO）. Methods We infused human Bcl-2-expressing plasmid （pBcl-2） into the lateral ventricle immediately after 30 min of MCAO, injected 5＇-bromodeoxyuridine （BrdU） intraperitoneally to label proliferative cells, and microinjected fluorogold （FG） into the substantia nigra at 11 weeks of reperfusion followed by multiple immunostaining of striatonigral projection neurons at 12 weeks. Results We found that pBcl-2 treatment significantly increased the number of newborn neurons （BrdU＋-NeuN＋） in the striatum ipsilateral to the MCAO. We further detected newborn striatonigral projection neurons （BrdU＋-FG＋-NeuN＋） in the ipsilateral striatum at 12 weeks. More interestingly, the number of newborn striatonigral projection neurons （BrdU＋-FG＋） was significantly increased by pBcl-2 treatment compared to that by pEGFP, a control plasmid. Conclusion Taken together, we found that Bcl-2 overexpression in the brain enhanced the generation of newborn striatonigral projection neurons. This provides a potential strategy for promoting the reestablishment of neural networks and brain repair after ischemic injury.

摘要：This paper took a 100,000 DWT LNG fuel powered ship as the research *** on the idea of"temperature matching,cascade utilization"and combined with the application conditions of the ship,a horizontal three-level nested Rankine cycle full-generation system which combined the high-temperature waste heat of the main engine flue gas with the low-temperature cold energy of LNG was proposed in this ***,based on the analysis and selection of the parameters which had high sensitivity to the system performance,the parameters of the proposed system were optimized by using the genetic *** optimization,the exergy efficiency of the marine LNG gasification cold energy cascade utilization power generation system can reach 48.06%,and the thermal efficiency can reach 35.56%.In addition,this paper took LNG net power generation as the performance index,and compared it with the typical LNG cold energy utilization power generation system in this *** results showed that the unit mass flow LNG power generation of the system proposed in this paper was the largest,reaching 457.41 k W.

摘要：针对基于港口评价和基于运筹优化两类选址方法的局限性,从中国运营者的视角出发,构建了同时考虑港口群物流网络总成本最低和枢纽港供给条件最优的海外港口群集装箱枢纽港选址模型,并采用二代非支配排序遗传算法(NSGA-Ⅱ)进行求解。以非洲西海岸港口群为案例,应用构建的选址模型对不同情境下的集装箱枢纽港选址方案进行了模拟分析,并基于枢纽港加权选择概率得出了港口群内集装箱枢纽港建设的优先级顺序。案例模拟结果表明:该选址模型能够综合两类选址方法的优点,且可以基于NSGA-Ⅱ算法实现高效求解,所得选址结果更符合中国运营者的利益;基于中国运营者视角,在非洲西海岸港口群中,以丹吉尔港和德班港为首的部分港口具有枢纽价值。

摘要：设施农业种植中的土壤由于常年过度种植和缺少四季的自然整理,土壤板结严重。传统的旋耕耕深只能达到10~15 cm,15 cm以下的部分形成了厚厚的犁底层,降低了土壤的通透性和蓄水保肥能力。针对这一问题,研制了一种深耕作业机具,耕深可达到30 cm。深耕后的作业质量能够达到旋耕作业标准。从动力选型、作业刀具设计及刀具排列等方面进行了详细介绍。

摘要：为了满足三通管液压成形过程的监测和过程控制的需求,构建了一个基于有限元数据驱动的机器学习框架用于多物理场的实时预测,包括:数据生成模型构建,建立能够准确描述塑性成形过程的有限元模型;数据集生成,结合成形工艺特点和成形设备参数范围要求进行实验设计,同时通过有限元模拟创建数据集,用于机器学习模型的训练;模型训练,选择机器学习算法就有限元模拟生成的数据集进行学习,建立边界位移与材料内部位移场的映射;多物理场计算,基于预测位移场推导材料内部应变、应力以及厚度场等的分布。采用该框架构建了基于CPB06屈服准则的纯钛三通管液压成形有限元模型,在此基础上通过加载路径全因子模拟实验生成了机器学习数据集,并采用随机森林和梯度提升算法实现了材料内部位移的实时预测,计算出了等效应变、等效应力和管材壁厚的分布。将上述预测模型用于全新工况的三通管液压成形,结果表明,预测误差不超过5%,说明构建的集成有限元方法的机器学习框架可以解决有限元模型无法在线分析的问题,实现对塑性加工过程中多物理场的实时预测。

摘要：A novel degradable pH-sensitive hydrogel with pendent carboxyl groups was designed and synthesized from ethylenediaminetetraacetic dianhydride （EDTAh） and butanediamine （BDA） with dicyclohexylcarbodiimide （DCC） as a condensating agent and BDA as a crosslinking agent. The obtained polymers were characterized by ^13C NMR, ^1H NMR and FTIR. The swelling experiments of the hydrogel in pH 3, 7, and 12 media indicated much higher swelling ratio in pH 12 media than in pH 3 and pH 7 media, exhibiting sound pH sensitivity. The pH sensitivity of this type of hydrogel may be regulated through controlling the type and the dose of the crosslinking agent.

摘要：泡排采气工艺因经济高效、施工便捷等优势在国内外各大气田应用广泛,在众多排水采气工艺中扮演主力军角色。为准确揭示泡排井集气管流流型、压降规律及泡沫稳定性,设计加工了一套泡排井集气管流特性模拟实验装置,以含聚合物的气井地层水为介质对其进行可靠性验证。实验选用UT-5D型起泡剂,在气液比0.55~137.42范围内,测试分析起泡剂浓度、起始温度、管径等7个因素影响下的气-液-泡沫多相管流流型、阻力特性及泡沫稳定性。基于相关性和多元回归分析方法,揭示了泡沫高度、压力梯度与各因素的内在关系。结果表明:随气液比增加,管内依次出现液-泡沫分层流、气-泡沫段塞流、气-泡沫波动流、气-泡沫分层流4种流型;气液比、起泡剂浓度和管长对压力梯度和泡沫高度影响显著,其余因素影响均较小,不同因素影响泡沫高度和压降的显著性强弱分别为气液比>起泡剂浓度>管长>温度>弯管>聚合物>管壁粗糙度>管径、气液比>起泡剂浓度>管长>管径>管壁粗糙度>温度>弯管>聚合物;泡沫高度、压力梯度与气液比均表现为强负相关,上述研究可为泡排采气工艺参数优化提供指导。

摘要：混凝土防渗墙是覆盖层上土石坝坝基关键防渗结构,坝基防渗墙失效使得大坝不能正常运行,甚至导致灾难发生。为此,建立了有限元—比例边界元耦合的深厚覆盖层上土石坝防渗墙的跨尺度精细化分析模型,采用损伤分析和破损后防渗功能目标评价的精细化分析方法,研究了混凝土防渗墙的受力致损机理,量化了对防渗性能的影响。结果表明,基岩支撑作用使防渗墙底部出现近似垂直方向的高压应力;防渗墙与基岩不规则位置相交的局部区域变形受限,可能出现高应力甚至损伤破坏,为薄弱区域;传统方法计算的防渗墙拉应力达11 MPa,远超材料强度,结果失真难以合理评价防渗墙安全性;损伤和渗流分析计算的防渗墙最大拉损伤因子为0.7,坝基渗流量仅增加125 m^(3)/d(9.11%),防渗功能可满足要求。

摘要：A systemic investigation was done on the chemistry and crystal structure of boundary phases in sintered Ce9Nd21FebalB1 （wt%） magnets. Ce2Fe14B is believed to be more soluble in the rare-earth （RE）-rich liquid phase during the sintering process. Thus, the grain size and oxygen content were controlled via low-temperature sintering, resulting in high coercivity and maximum energy products. In addition, Ce formed massive agglomerations at the triple-point junctions, as confirmed by elemental mapping results. Transmission electron micros- copy （TEM） images indicated the presence of （Ce,Nd）Ox phases at grain boundaries. By controlling the composition and optimizing the preparation process, we successfully obtained Ce9Nd21FebalBx sintered magnets; the prepared magnets exhibited a residual induction, coerciv- ity, and energy product of 1.353 T, 759 kA/m, and 342 kJ/m3, respectively.

摘要：准确、快速检测茶叶病害对茶叶产业经济意义重大。然而,病害叶片尺度变化、相互遮挡、复杂背景等问题大大降低了检测精度。提出了一种融合通道和空间注意力的茶叶病害目标检测方法,以实现准确、高效的病害检测。首先,利用多层的自注意力机制提取茶叶病害的多尺度特征,以获取茶叶图像在不同尺度下的局部细节特征;其次,引入新的通道注意力模块以提取更丰富的通道信息,同时抑制复杂背景噪声并增强模型特征表示能力。此外,设计一种新的空间注意力模块进一步提取特征的空间关系、减少冗余信息并优化计算开销。实验结果表明,融合通道和空间注意力的茶叶病害检测方法能应对叶片的尺度变化、相互遮挡和背景复杂等挑战。