Protective effect of retaining wall on rock avalanche:A case study of Nayong rock avalanche in China

Rock avalanches are generally difficult to prevent and control due to their high velocities and the extensive destruction they cause.However,barrier structures constructed along the path of a rock avalanche can partially mitigate the magnitudes and consequences of such catastrophic events.We selected a rock avalanche in Nayong County,Guizhou Province,China as a case to study the effect of the location and height of a retaining wall on the dynamic characteristics of rock avalanche by using both actual terrain-based laboratory-model tests and coupled PFC3D-FLAC3D numerical simulations.Our findings demonstrate that a retaining wall can largely block a rock avalanche and its protective efficacy is significantly influenced by the integrity of the retaining wall.Coupled numerical simulation can serve as a powerful tool for analyzing the interaction between a rock avalanche and a retaining wall,facilitating precise observations of its deformation and destruction.The impact-curve characteristics of the retaining wall depend upon whether or not the rock avalanche-induced destruction is taken into account.The location of the retaining wall exerts a greater influence on the outcome compared to the height and materials of the retaining wall,while implementing a stepped retaining-wall pattern in accordance with the terrain demonstrates optimal efficacy in controlling rock avalanche.

CFD investigation of effect of nanofluid filled Trombe wall on 3D convective heat transfer

A numerical investigation was carried out on the effect of carbon nanotube(CNT)-water-nanofluid-filled Trombe wall on heat transfer and fluid flow inside a 3 D typical room.Time depending governing equations are considered with applying hot temperature at the left surface(collector) of the Trombe wall.The left wall(glazing) of the room and a square part(window) at the right wall are considered at cold temperature.The effects of Rayleigh number and the nanofluid volume fractions and the Trombe wall height on the temperature field,flow structure and heat transfer rate,are studied.The results show that the addition of nanoparticles and the increase of the Trombe wall height,enhance the heat transfer considerably and affect the flow structure and the temperature field.

A case study on behaviors of composite soil nailed wall with bored piles in a deep excavation

A complete case of a deep excavation was explored. According to the practical working conditions, a 3D non-linear finite element procedure is used to simulate a deep excavation supported by the composite soil nailed wall with bored piles in soft soil. The modified cam clay model is employed as the constitutive relationship of the soil in the numerical simulation. Results from the numerical analysis are fitted well with the field data, which indicate that the research approach used is reliable. Based on the field data and numerical results of the deep excavation supported by four different patterns of the composite soil nailed wall, the significant corner effect is founded in the 3D deep excavation. If bored piles or soil anchors are considered in the composite soil nailed wall, they are beneficial to decreasing deformations and internal forces of bored piles, cement mixing piles, soil anchors, soil nailings and soil around the deep excavation. Besides, the effects due to bored piles are more significant than those deduced from soil anchors. All mentioned above prove that the composite soil nailed wall with bored piles is feasible in the deep excavation.

Weaving 3D highly conductive hierarchically interconnected nanoporous web by threading MOF crystals onto multi walled carbon nanotubes for high performance Li-Se battery

Lithium-selenium(Li-Se)battery has attracted growing attention.Nevertheless,its practical application is still impeded by the shuttle effect of the formed polyselenides.Herein,we report in-situ hydrothermal weaving the three-dimensional(3 D)highly conductive hierarchically interconnected nanoporous web by threading microporous metal organic framework MIL-68(Al)crystals onto multi-walled carbon nanotubes(MWCNTs).Such 3 D hierarchically nanoporous web(3 D MIL-68(Al)@MWCNTs web)with a very high surface area,a large amount of micropores,electrical conductivity and elasticity strongly traps the soluble polyselenides during the electrochemical reaction and significantly facilitates lithium ion diffusion and electron transportation.Molecular dynamic calculation confirmed the strong affinity of MIL-68(Al)for the adsorption of polyselenides,quite suitable for Li-Se battery.Their hexahedral channels(1.56 nm)are more efficient for the confinement of polyselenides and for the diffusion of electrolytes compared to their smaller triangular channels(0.63 nm).All these excellent characteristics of 3 D MIL-68(Al)@MWCNTs web with suitable confinement of a large amount of selenium and the conductive linkage between MIL-68(Al)host by MWCNTs result in a high capacity of 453 m Ah/g at 0.2 C with 99.5%coulombic efficiency after 200 cycles with significantly improved cycle stability and rate performance.The 3 D MIL-68(Al)@MWCNTs web presents a good performance in Li-Se battery in term of the specific capacity and cycling stability and also in terms of rate performance compared with all the metal-organic framework(MOF)based or MOF derived porous carbons used in Li-Se battery.

Behavior of braced wall embedded in saturated liquefiable sand under seismic loading

It is well known that the generation of excess pore water pressure and/or liquefaction in foundation soils during an earthquake often cause structural failures.This paper describes the behavior of a small-scale braced wall embedded in saturated liquefiable sand under dynamic condition.Shake table tests are performed in the laboratory on embedded retaining walls with single bracing.The tests are conducted for different excavation depths and base motions.The influences of the peak magnitude of the ground motions and the excavation depth on the axial forces in the bracing,the lateral displacement and the bending moments in the braced walls are studied.The shake table tests are simulated numerically using FLAC 2D and the results are compared with the corresponding experimental results.The pore water pressures developed in the soil are found to influence the behavior of the braced wall structures during a dynamic event.It is found that the excess pore water pressure development in the soil below the excavation is higher compared to the soil beside the walls.Thus,the soil below the excavation level is more susceptible to the liquefaction compared to the soil beside the walls.

3D技术下动画电影的新境界——点评电影《WALL·E》

当13部各类预告片纷至沓来后，才缓缓问世的《WALL·E》露出峥嵘。这一故事是两极化的末世预言。当主角出现了偏离性，即超过了其本身所处的生活范畴，才会出现戏剧性的与环境不兼容的结果。在这部影片里，WALL·E的不兼容来自另一半的赐予，即EVE，和她带来的爱情。皮克斯的胜利并不是梦工厂的失败，只是更强大而已。这一次，除了题材和音画，皮克斯全面压倒了对手。

Development of ToSPACE for Pipe Wall Thinning Management in Nuclear Power Plants

A number of piping components in the secondary system of nuclear power plants are exposed to aging mechanisms such as FAC (Flow-Accelerated Corrosion), cavitation, flashing, SPE (Solid Particle Erosion), LDIE (Liquid Droplet Impingement Erosion), etc. Those mechanisms may lead to thinning, leak, or rupture of the components. Due to the pipe ruptures caused by wall thinning in Surry unit 2 of USA in 1986 and in Mihama unit 3 of Japan in 1994, the pipe wall thinning management has emerged as one of the most important issues in nuclear power plants. To manage the pipe wall thinning in the secondary system, Korea has used a foreign program since 1996. As using the foreign country’s program for long term, it was necessary to improve from the perspective of the users. Accordingly, KEPCO-E & C has started to develop the 3D-based pipe wall thinning management program (ToSPACE, Total Solution for Piping And Component Engineering management) from eight years ago, and the development was successful. This paper describes the major functions included in ToSPACE program, such as 3D-based DB (Database) buildup, development of FAC and erosion evaluation theories, UT (Ultra-sonic Test) data reliability analysis, field connection with 3D, automatic establishment of long-term inspection plan, etc. ToSPACE program was developed to allow site engineers performing the selection of inspection quantity at each refueling outage, UT data reliability analysis, UT evaluation, determination of next inspection timing, identification of the inspecting and replacing components in 3D drawings, etc., to access easily.

Anti-malarial drug,artesunate,as a novel therapeutic drug target for airway wall remodeling in asthma

OBJECTIVE Airway wall remodeling(AWR),which refers to structural changes in the airway,is a key characteristic of asthma.Airway smooth muscle(ASM)cell hypertrophy and hyperplasia contributes to AWR.Glucocorticoids,which are used as first line therapy for the treatment of asthma,reduce ASM proliferation but the magnitude of their anti-proliferative actions is dependent on the mitogen used.Moreover,glucocorticoid therapy is accompanied by many side effects.Artesunate,a semi-synthetic artemisinin derivative,has been widely used to treat malaria with minimal toxicity.Artesunate has been shown to attenuate allergic airway inflammation in mice.However,its role in treating AWR in asthma is not known.In this study,we hypothesize that artesunate has anti-proliferative actions on ASM cells,potentially reversing AWR.METHODS and RESULTS Quiescent primary human ASM cells were pre-treated(1h)with artesunate(3,10,30μmol·L-1)before being stimulated with either FBS(10%)or thrombin(0.3U·mL-1).Following 48 h stimulation with mitogen,cells were counted using a haemocytometer.Dexamethasone(Dex,100nmol·L-1)was used as a positive control.Artesunate concentration-dependently reduced cell number and the magnitude of inhibition appeared to be non-mitogen dependent.Moreover,we examined the effect of artesunate on two important signalling proteins involved in cell proliferation,ERK1/2phosphorylation and cyclin D1 protein levels.Artesunate reduced cyclin D1 protein levels significantly following 20 h stimulation with either thrombin or FBS but had no effect on ERK1/2 phosphorylation following 6h stimulation.Importantly,artesunate(30μmol·L-1),but not Dex,inhibited the phosphorylation of Akt,which is upstream of cyclin D1.Next,we show that the inhibitory effect of artesunate,but not Dex,on ASM cell number is retained at least 24h post-treatment following stimulation with FBS.In an acute murine model of allergic asthma,artesunate treatment decreased sm-α-actin positive cells and cyclin D1 protein abundance in the ovalbumin sensitized and challenged mice.CONCLUSION We have shown that artesunate regulates the PI3K/Akt pathway to inhibit the proliferation of primary human cultured ASM cells.This is an alternative mode of action,in comparison to glucocorticoids such as Dex.The anti-proliferative effect of artesunate was further validated in vivo.Thus,our study provides a basis for the future development of artesunate as a novel anti-AWR agent that targets ASM hyperplasia via the PI3K/Akt pathway.Moreover,artesunate may be used as an add-on therapy for asthmatic patients.

阿拉伯木聚糖、β-D-葡聚糖和α-纤维素涂层对杏果活性氧代谢的影响

使用阿拉伯木聚糖(arabinoxylan,AX)、(1,3;1,4)-β-D-葡聚糖((1,3;1,4)-β-D-glucan,BG)和α-纤维素复合溶液对采后杏果进行涂层处理,探究谷物细胞壁多糖涂层对采后杏果活性氧代谢系统的影响,并阐明其作用机理。结果表明:涂层能够有效抑制丙二醛和活性氧含量的上升,对照组的丙二醛、H2O2和O2-含量分别比ABF-C8处理组(α-纤维素质量浓度8 g/100 mL)高37.50%、33.33%和57.14%;此外,涂层处理还能维持杏果的抗氧化能力和抗氧化酶活性,其抗坏血酸和总酚含量分别比对照组高73.33%和8.40%;小麦细胞壁多糖涂层能够延缓杏果实呼吸过程中活性氧的产生和积累,从而保持细胞膜的完整性,同时涂层能够使水果和外界环境形成气体和水分之间的屏障,维持活性氧清除酶活性及抗氧化能力,从而延长采后杏果的贮藏期。

一种基于动态最小成本路径启发式算法的水冷壁爬壁机器人路径规划方法

为了满足水冷壁爬壁机器人在复杂多变的表面进行工作的需求,文章针对其持续爬移运动的特点,提出了一种基于动态最小成本路径启发式(D^(*))算法的水冷壁爬壁机器人路径规划方法。该方法通过栅格法对须爬壁的工作环境进行建模,利用D^(*)算法的动态重规划特性,实现机器人在复杂多变的水冷壁表面环境下的有效路径规划。实验结果表明,该方法能够使爬壁机器人高效地完成水冷壁表面的路径规划任务。

用于标记细菌肽聚糖的荧光D-氨基酸的研究进展

肽聚糖(Peptidoglycan,PG)是细菌细胞壁的主要组成成分,对于维持细胞形态、稳定胞体渗透压起重要作用,干扰PG的生物合成会破坏细胞壁结构,导致细菌死亡。细菌中普遍存在L-和D-氨基酸,其中D-氨基酸是PG合成的基本单元。荧光D-氨基酸(Fluorescent D-amino acids,FDAAs)是修饰有荧光基团的D-氨基酸类似物,可被细菌内源性转肽酶识别并整合在PG层中,所携带的荧光基团能够在新合成的PG上释放荧光信号。哺乳动物细胞通常无法识别D-氨基酸,因此,这种荧光标记策略能够在生物体内应用。近年来,FDAAs已成为可视化细菌PG生长和重塑的强大工具。本文围绕目前已开发的FDAAs展开讨论,并介绍这种标记策略在可视化PG增长、细菌抗生素敏感性分析、肠道菌群研究以及细菌感染治疗等的应用,最后对该研究方向的发展前景进行了展望。

2型糖尿病患者左室心肌力学特性参数与血25(OH)D、hs-CRP及IL-6表达的相关性

目的研究2型糖尿病患者左室心肌力学特性参数与血25-羟基维生素D(25(OH)D)、高敏C反应蛋白(hs-CRP)及白细胞介素-6(IL-6)表达的相关性。方法选择2021年1月—2023年2月本院收治的103例2型糖尿病患者作为观察组,依据血糖控制是否良好分为血糖良好组(82例)和血糖不良组(21例);另选取同期来本院体检的90名健康者作为对照组。比较观察组与对照组一般资料、左室心肌力学特性参数(左室舒张末期内径、左室后壁舒张末期厚度、左室收缩末期内径、左室射血分数)、25(OH)D、hs-CRP及IL-6水平,比较血糖良好组与血糖不良组左室心肌力学特性参数(左室舒张末期内径、左室后壁舒张末期厚度、左室收缩末期内径、左室射血分数)、25(OH)D、hs-CRP及IL-6水平。结果观察组与对照组性别、年龄、身体质量指数(BMI)、舒张压、收缩压、吸烟史、饮酒史、高血压史、糖尿病史、总胆固醇、血红蛋白(Hb)、钙、磷、白细胞(WBC)及尿酸比较,差异无统计学意义(P>0.05);观察组与对照组左室射血分数比较,差异无统计学意义(P>0.05),观察组左室舒张末期内径、左室后壁舒张末期厚度、左室收缩末期内径、hs-CRP及IL-6高于对照组(P<0.05),观察组25(OH)D水平低于对照组(P<0.05);不同血糖控制水平两组左室收缩末期内径、左室射血分数比较,差异无统计学意义(P>0.05),血糖良好组左室舒张末期内径、左室后壁舒张末期厚度、hs-CRP及IL-6低于血糖不良组(P<0.05),血糖良好组25(OH)D高于血糖不良组(P<0.05);Pearson相关分析结果显示:左室舒张末期内径、左室后壁舒张末期厚度、左室收缩末期内径均与25(OH)D呈负相关(P<0.05),与hs-CRP、IL-6呈正相关(P<0.05)。结论2型糖尿病患者心脏结构及25(OH)D、hs-CRP、IL-6水平发生改变,且左室心肌力学特性参数与25(OH)D,hs-CRP、IL-6水平相关。

续断化学成分研究

目的:对续断的化学成分进行分离和鉴定。方法:采用硅胶色谱柱、RP-C18柱色谱等色谱方法对续断甲醇提取物进行成分分离和纯化,根据理化性质和光谱数据鉴定化合物的结构。结果:分离鉴定了12个化合物,分别为:蔗糖(1)、β-谷甾醇(2)、齐墩果酸(3)、Triplostoside A(4)、马钱苷(5)、马钱酸(6)、獐牙菜苷(7)、Epi-Vogelo-side(8)、Vogeloside(9)、木通皂苷D(10)、Cauloside A(11)、7-Deoxyloganic acid(12)。结论:其中,化合物8、9、12为首次从该植物中分离得到。

川续断的化学成分研究

从川续断(Dosacus asper Wall)的根中分得六个化合物(Ⅰ～Ⅵ)。Ⅰ,Ⅱ,Ⅲ和Ⅵ分别鉴定为蔗糖、胡萝卜甙、β-谷甾醇和akebia saponin D.Ⅵ和Ⅴ为新化合物,根据光谱分析和化学方法证明其结构分别为3-O-(4-O-乙酰基)-α-L-吡喃阿拉伯糖常春藤皂甙元28-O-β-D-吡喃葡萄糖-(1→6)-β-D-吡喃葡萄糖酯甙和3-O-α-L-吡喃阿拉伯糖齐墩果酸28-O-β-D-吡喃葡萄糖-(1→6)-β-D一-吡喃葡萄糖酯甙。

川续断中的新三萜皂甙

从川续断(Dispsacus asper Wall.)根的乙醇提取物中得到二个新三萜皂甙(Ⅶ和Ⅷ)。根据光谱分析、化学反应及双向高效薄层层析结果,证明其结构分别为:3-O-β-D-吡喃葡萄糖(1→3)-α-L-吡喃鼠李糖(1→2)-α-L-吡喃阿拉伯糖常春藤皂甙元28-O-β-D-吡喃葡萄糖(1→6)-β-D-吡喃葡萄糖酯甙和3-O-α-L-吡喃鼠李糖(1→3)-β-D-吡喃葡萄糖(1→3)-α-L-吡喃鼠李糖(1→2)-α-L-吡喃阿拉伯糖-常春藤皂甙元28-O-β-D-吡喃葡萄糖(1→6)-β-D-吡喃葡萄糖酯甙。

川续断的研究进展

从化学成分、药理作用及临床应用等方面综述了川续断的研究进展 。

川续断中皂甙Ⅸ和Ⅹ的结构研究

从川续断(Dipsacus asper Wall.)根的乙醇提取物中得到二个新三萜皂甙(Ⅸ和Ⅹ),根据光谱分析和化学反应,其结构分别确定为3-O-[β-D-吡喃木糖(1→4)-β-D-吡喃葡萄糖(1→4)][α-L-吡喃鼠李糖(1→3)]-β-D-吡喃葡萄糖(1→3)-α-L-吡喃鼠李糖(1→2)-α-L-吡喃阿拉伯糖-常春藤皂甙元(Ⅸ)及其28-O-β-D-吡喃葡萄糖(1→6)-β-D-吡喃葡萄糖酯甙(Ⅹ)。

石菖蒲及其有效成分-细辛醚对癫痫幼鼠海马区神经元N-甲基-D-天冬氨酸受体表达的影响

目的探讨在戊四氮(PTZ)诱发的癫痫动物模型中,石菖蒲及其主要成分α-细辛醚对海马区神经元N-甲基-D-天冬氨酸受体1(NMDAR1) mRNA表达水平的影响。方法3周龄Wistar幼鼠ipPTZ60mg/kg建立癫痫模型。动物模型随机分为模型对照组、石菖蒲组、α-细辛醚组,另设正常对照组。各组均ig给药。正常对照组给予生理盐水1.0mL/d,其余各组分别给予石菖蒲2350mg/(kg·d),α-细辛醚29mg/(kg·d),连续7d。次日ipPTZ60mg/kg,观察动物行为变化,1d后处死动物,取左侧大脑固定用于原位杂交;取右侧海马组织用于半定量RT-PCR,检测海马CA1、CA3区神经元NMDRA1 mRNA的表达情况。结果原位杂交结果显示,阳性染色颗粒定位于海马神经元胞质内。石菖蒲和α-细辛醚治疗组海马区神经元阳性细胞数和平均吸光度均明显少于模型对照组(P<0.05)。半定量RT-PCR结果显示,石菖蒲和α-细辛醚治疗组海马组织中NMDAR1 mRNA的相对表达量均较显著低于模型对照组(P<0.05)。结论石菖蒲和α-细辛醚可能通过抑制海马区神经元谷氨酸NMDAR1表达而发挥抑制PTZ诱发的幼鼠癫痫发作。

氯喹对戊四氮致痫大鼠皮质和海马谷氨酸和NMDAR1表达的影响

目的观察氯喹对戊四氮致痫大鼠皮质和海马谷氨酸(glutamate,Glu)和N-甲基-D-天冬氨酸受体1(NMDAR1,NR1)表达的影响,探讨氯喹在癫痫发生发展过程中对神经递质传导的作用。方法48只健康雄性SD大鼠随机分为对照组(12只)、戊四氮致痫组(60mg/kg,i.p.,18只)和氯喹干预组(0.61mg/kg,i.c.v.,18只)。每组分6个时间点:1h、2h、4h、8h、12h和24h。观察大鼠行为表现和脑电图改变,用免疫组化检测大鼠皮质和海马Glu和NR1的变化。结果对照组无痫样发作,戊四氮致痫组有重型的痫样发作(Ⅲ-Ⅴ级),氯喹干预组有轻型的痫样发作(Ⅰ-Ⅲ级)(P<0.05);戊四氮致痫组脑电记录呈频发高幅的痫样波,氯喹干预组痫样波幅低且缓;Glu和NR1在戊四氮致痫组表达强,以海马为著,与对照组比较有显著性差异(P<0.05),氯喹干预组与对照组比较无显著性差异(P>0.05)。结论氯喹通过对戊四氮致痫大鼠皮质和海马神经递质Glu和NR1信号传导通路的抑制作用,影响致痫大鼠痫样发作的发生和发展。

GC-MS法分析“发汗”对续断挥发性成分的影响

目的通过GC-MS法分析＂发汗＂对续断Dipsacus asper Wall.ex Henry挥发性成分的影响。方法水蒸气蒸馏法提取续断乙醚萃取物挥发油后,GC-MS法鉴定其成分,面积归一化法计算各成分相对含有量。结果续断在＂发汗＂前后均鉴定出28种成分,其中26种为共有成分。＂发汗＂前未检测出9,12,15-十八碳三烯酸甲酯和9-亚甲基-9H-芴,而＂发汗＂后未检测出顺-13-十八碳烯酸和十七烷醇。结论 ＂发汗＂后续断中共有成分的含有量均有明显变化,变化范围为30.81%-99.34%。