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某铁路站房屋盖钢结构为双曲悬挑双向交叉浪花状空间管桁架形式，安装精度要求高，节点错综复杂，施工难度大。对该结构施工过程中遇到的重、难点进行了介绍，详细分析了浪花状屋盖钢结构的施工关键技术，针对浪花状屋盖独特的造型特点及施工条件，提出了“整体卧式拼装，双机空中转体”的施工技术，并利用有限元动态仿真模拟技术分析了浪尖结构高空转体过程中的变形和受力情况，结合仿真分析数据对双机抬吊过程进行关键点位的监测，在确保施工安全和质量满足规范要求的前提下，实现了屋盖钢结构的高效率、高精度建造，为同类屋盖钢结构的施工提供一定的参考。

精确掌握材料高温下的性能参数,对结构抗火设计的准确性具有十分重要的意义。以S30408奥氏体不锈钢为研究对象,在现有S30408不锈钢高温材料性能试验的基础上,研究发现S30408不锈钢在同种条件下,相比碳钢具有较低的升温速率,且S30408不锈钢在600℃时仍能保持50%以上的强度与刚度。但不锈钢具有更大的热膨胀率,高温给结构的稳定性带来的威胁更大。其次,对比分析了国内外学者所提出的常温及高温下不锈钢的本构模型,根据S30408不锈钢高温下性能参数的变化规律,欧洲规范给出的建议值偏不安全,建议在不锈钢结构设计中采用Rasmussen模型,在结构抗火的数值模拟分析中采用Chen和Young的模型。

乌镇世界互联网大会主展馆采用屋脊张弦梁-悬链梁杂交结构体系,形成90 m×200 m的全无柱空间。为了实现整个展馆的快速建造,整个展馆项目运用了动态模块化系统和全预制装配的逻辑。上层建筑结构设置了大量预应力索,形式新颖、受力复杂、施工难度大。为此,对主展馆钢结构施工过程中的关键技术进行了研究,主要包括柔性大跨悬链梁循环安装技术、实腹-格构组合支撑体系应用技术、多索系预应力结构张拉技术等关键技术,并针对现行规范中上端自由的单阶柱稳定计算方法,给出建议的适用范围,为同类型结构和支撑体系的推广应用和类似复杂空间结构的施工提供了一定参考。

为提高钢结构工厂质量检测管理的信息化水平,实现质检过程可视化和信息共享,提出一种结合BIM和WebGL技术的面向钢结构工厂无纸化质检的系统。在明确系统需求、定义相应功能、描述系统工作流程、建立系统整体框架的基础上,基于BIM及WebGL技术搭建了系统平台。平台利用BIM技术实现BIM模型到构件图纸再到构件属性智能拆分读取,利用WebGL技术实现构件图纸在浏览器中渲染及操作。研究表明,结合钢结构工厂质检应用场景设计面向钢结构工厂的无纸化质检应用打破了常规的质检方法,实现了工厂加工质量精细化管理,提高了构件的加工质量,实现了全过程的质检信息分享。

为了对西藏人烟稀少地区和单跨段传输距离很长的光纤链路进行检测,文章提出一种用于提高线性调频（LFM）光时域反射仪（OTDR）空间分辨率和测量距离的方法。该方法通过产生一个调频范围为200 MHz、脉冲宽度为20μs的强度调制模拟LFM信号来实现高的空间分辨率和大的探测距离。使用该方法在西藏地区的实际光纤传输链路中进行了实验测试,实验结果表明,该方法能够在长度为240 km的光纤链路上实现0.000 53 km的空间分辨率,与相同测量参数的单脉冲OTDR相比,动态范围提高了8.5 dB。

钢结构预拼装是检测构件加工精度及保证结构在现场顺利安装的主要技术手段,它的实现方式主要有实体预拼装和虚拟预拼装两种。为更加有效地管控项目成本,通过建立成本控制数学模型来分析钢结构虚拟预拼装技术及钢结构实体预拼装技术在北京新机场项目中的应用,分别从钢结构预拼装技术比对、两种预拼装方案之间的成本影响因素、实际项目数据佐证、效益分析等几个方面对预拼装成本进行系统阐述。通过成本分析模型,优选拼装方案;通过对主要因子控制,进而达到更好的成本控制。

为了研究薄壁组合型箱体剪力墙-柱体系模拟预拼装,进行了某大型塔楼19层第9节柱和钢板剪力墙部分构件(共18根)的预拼装模拟。试验详细分析了预拼装方案的可行性及准确性,在此基础上结合钢结构安装顺序,构件主次关系和安装基准面,介绍了结构形式复杂的薄壁组合型预拼装模拟思路。研究结果表明,三维激光扫描仪可大幅提高测量自身精度,让控制点繁多的薄壁组合型实测模型与实测构件最大程度的接近;采用的预拼装模拟实现了薄壁组合型结构的检测过程及拟合结果可视化;预拼装模拟在薄壁组合型箱体剪力墙-柱体系中的研究可为后续研究提供参考。

针对现有的光时域反射仪（OTDR）在监测带有掺铒光纤放大器（EDFA）的长途多跨段光纤链路时,为克服EDFA增益的波动需增加一个额外的补光来保持功率稳定的问题,文章基于线性调频OTDR提出了一种无需补光穿越EDFA的长途多跨段光纤监测技术。该技术利用线性调频准连续光作为探测光,可以避免EDFA增益的波动。同时通过分数域傅里叶滤波来去除级联EDFA累积的自发辐射白噪声,从而提高接收信号的信噪比。实验结果表明,该技术能够准确地测出中长途多跨段光纤链路中EDFA和连接点处的反射事件。

为了控制自由空间光通信系统的成本、体积和功耗,便于系统的维护与运行,针对现有的自由空间光通信系统一般采用强度调制/直接解调的方式,提出了一种新型的基于K平均算法的接收机结构,并从执行复杂度、鲁棒性和差错性能等方面与经典算法进行比较分析。结果显示,当数据块长度达到1 000时,所提算法性能可以逼近理想接收机性能。

：【目的】研究泮托拉唑对肿瘤恶病质骨骼肌消耗的缓解作用。【方法】将24只BALB/c小鼠随机分为3组，分别为正常组（NN）、恶病质组（CC）、干预组（PPI），每组8 只。荷瘤小鼠采用腋下接种小鼠结肠癌细胞（c26），建立肿瘤恶病质模型。每日监测各组小鼠体质量、肿瘤大小及精神毛发等一般情况。接种后第12 天干预组采取泮托拉唑灌胃，其余组采取生理盐水灌胃。干预后第12 天处死小鼠收集标本。称量腓肠肌及肿瘤质量，测量肿瘤大小，HE 染色观察骨骼肌形态变化，血清ELISA 法检测IL-6、TNF-α水平，qRT-PCR 和Werstern blot 分别检测腓肠肌MuRF1、MAFBx、Myod1 和 myf5 的mRNA 和蛋白表达水平。【结果】与CC 组相比，PPI 组小鼠及腓肠肌质量分别增加39.8%和24.2%，腓肠肌纤维横切面积增加25.4%；PPI 组Myod1 和myf5 的mRNA 水平及蛋白表达水平明显高于CC 组（P < 0.05）；PPI 组血清IL-6 及 TNF-α水平较CC 组分别降低30.7%和18.9%；PPI 组MuRF1、MAFBx 蛋白表达水平明显低于CC 组（P < 0.05）。【结论】泮托拉唑对肿瘤恶病质骨骼肌消耗具有保护作用，其机制可能与抑制炎症及泛素蛋白酶体途径（UPS），上调生肌调节因子（MRF）有关

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Xixiayuan Reservoir, as a counter-regulating reservoir of Xiaolangdi Reservoir, plays an important role in regulating the unsteady flow of Xiaolangdi Reservoir. Since the operation of Xixiayuan Reservoir, the reservoir has shown a continuous trend of siltation. It is of great significance to study the siltation removal capacity of Xixiayuan Reservoir. Based on the measured water and sediment data of Xixianyuan Reservoir from 2011 to 2022, this paper made an in-depth analysis of the sediment discharge process and influencing factors of Xixianyuan Reservoir over the years. The research results show that the sediment discharge of Xixianyuan Reservoir is affected by multiple factors such as the reservoir operation mode and the conditions of incoming water and sediment. The sediment delivery ratio of the reservoir is significantly affected by the variation coefficient of discharge along the flow and the sediment discharge in the reservoir, and the sediment discharge ratio is significantly positively correlated with the variation coefficient of discharge along the flow and negatively correlated with the sediment discharge in the reservoir. The empirical formula of sediment discharge is established by regression analysis, with the coefficient of determination of 0.79, and the fitting effect is good. [ABSTRACT FROM AUTHOR]

In the forthcoming era of power grids emphasizing clean energy and green transportation, stringent safety and reliability standards are imperative. This study addresses the limitations of traditional reinforcement learning in managing the control performance degradation due to the extensive integration of new energy sources in microgrid by proposing a multi-step self-correcting Q-learning algorithm. This algorithm features a self-correcting estimator for accurate system state estimation and an eligibility trace mechanism to expedite convergence, facilitating rapid controller responses to system fluctuations and minimizing the impact of frequency regulation delays. The simulation section of this paper presents an enhanced two-area load frequency control model, integrating wind power and electric vehicle modules, and subjected to various disturbances to mimic real-world power system load changes. The results demonstrate that the proposed algorithm excels in control performance metrics when com- pared to existing methods. [ABSTRACT FROM AUTHOR]

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This study investigated the effects of climatic factors on radial growth of Picea schrenkiana var. tianschanica at various altitudes in Central Tianshan Mountains. Tree-ring core samples were collected at three altitudinal levels (1900, 2 200, 2 500 m) within the practice forest of Xinjiang Agricultural University. Dendrochronological techniques, including temperature, precipitation, the standardized precipitation evapotranspiration index, and the Palmer drought severity index, were employed to analyze meteorological data from 1955 to 2022. The results indicate that at low altitudes, tree-ring width is positively correlated with previous June and current June-August temperatures, previous August precipitation, and the current June-September Palmer drought severity index (P<0.05). At mid-altitudes, tree ring width was positively correlated with the previous June temperature, August precipitation, and previous June-August standardized precipitation evapotranspiration index (P<0.05). At high altitudes, tree-ring width was negatively correlated with the current January temperature and previous November to the current March standardized precipitation evapotranspi- ration index (P<0.05), but positively correlated with the current June-July precipitation (P<0.05). Therefore, in the forest, P. schrenkiana var. tianschanica growth is closely linked to the environmental moisture conditions, which vary with altitude. Precipi- tation is pivotal for radial growth of P. schrenkiana var. tianschanica at low altitudes, whereas temperature and precipitation jointly affected growth at mid-altitudes, with temperature exerting a greater impact than precipitation on radial growth at higher altitudes. [ABSTRACT FROM AUTHOR]

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The importance of question bank construction in medical education has been well proved. However, there are still some weaknesses in the clinical teaching assessment question bank, including the inconsistency between assessment and clinical practice, the lack of coherence in question bank updates, and the mismatch between proposition and student learning stage. To address these issues, this article explores a teaching model which connects flipped classroom with student independent proposition and analyzes the advantages of applying flipped classroom to question bank construction. The connection between the two effectively established a regular updating mechanism for question banks, thus improve the construction of question banks in current medical education. It may support the capacity building of students′ self-oriented and regulated learning and improve the quality of teaching assessment. [ABSTRACT FROM AUTHOR]

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Steel slag powder, S95 mineral powder, fly ash and desulfurization gypsum were used as raw materials, and multifaceted solid waste cementitious materials were prepared through the optimized design of the simple shape center of gravity method. The effect of composition on the mechanical properties of solid-waste mortar was analyzed by compressive and flexural strength tests of the mortar. X-ray diffraction (XRD), Fourier infrared spectroscopy (FT-IR) and thermogravimetric (TG) methods were used to investigate the strength formation mechanism of the multifunctional solid waste-based cementitious materials. The results show that the optimal mixing ratio of multifunctional solid waste-based cementitious materials is steel slag powder∶ S95 mineral powder∶ fly ash∶ desulfurization gypsum = 31∶ 38∶ 27∶ 4. The mechanical properties of multifunctional solid waste-based glued sand specimens show a tendency to increase and then decrease with the increase of steel slag powder admixture. S95 mineral powder contributed more to the early strength of the glued sand specimens, while excessive fly ash admixture is detrimental to the formation of the strength of the glued sand. The infrared absorption peak of SFMD showed the telescopic vibration peak of Si—O in C-S-H at 969 cm - 1, and the weight loss of C-S-H in SFMD is the most, which indicated that the synergistic effect among the components of the system is better. In addition, desulfurization gypsum can induce a more complete synergistic hydration reaction of the steel slag powder-S95 mineral powder-fly ash system to produce caliche that provides strength. [ABSTRACT FROM AUTHOR]

Reservoir sedimentation has always been a problem that troubles the reservoir management department. Scientifically and reasonably utilizing reservoir operation methods to achieve efficient sediment reduction in reservoirs is an effective means to solve reservoir sedimentation. This paper analyzed the reservoir sediment regulation of the Haibowan Reservoir on the Yellow River from 2019 to 2022, and combined the inflow and outflow water and sediment data during the flood season since the construction of the reservoir to carry out research on efficient sediment reduction of the Haibowan Reservoir. The research results indicate that: a) the goal of reservoir sediment reduction is achieved in 2019, 2020 and 2022, and the balance of erosion and sedimentation is basically achieved in 2019, while the sediment reduction effect is better in 2020 and 2022. b) The water level in front of the dam is a key factor affecting the sediment reduction of the Haibowan Reservoir, while the inflow water and inflow sediment are secondary factors affecting the outflow sediment volume. By fitting the influencing factors, an empirical formula for sediment reduction from the Haibowan Reservoir is obtained. c) Different combinations of inflow water and sediment require different scheduling measures to achieve efficient sediment reduction in the reservoir. Efficient sediment reduction in the reservoir can only be achieved by reasonably matching the inflow water and sediment conditions and the water level in front of the dam. [ABSTRACT FROM AUTHOR]

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In order to ensure the smooth implementation of the water pipeline during the submarine laying process, taking the submarine pipeline laying from Damen Island to Luxi Island in the first phase of the Dongtou Land Diversion Project as an example, in view of the problems such as long pipeline laying distance, different buried depths, complicated navigation conditions, and various types of submarine light (electricity) cables in the laying areas, the construction process of using a combination of bottom towing and directional drilling for submarine pipeline laying was adopted. The bottom towing method was used to lay the pipeline outside the navigable area, and the directional drilling process was used to lay the submarine pipeline in the navigable area, which can improve the efficiency and safety of submarine pipeline laying. At the same time, the process optimization of the pipeline weight process was optimized. The final decision was to increase the pipeline wall thickness as the weight scheme for this project through comparison, which improved the corrosion resistance of the pipeline and effectively controlled the construction cost. [ABSTRACT FROM AUTHOR]

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