有机化合物中的氯元素，称为有机氯。而有机氯农药作为一类重要的持久性有机污染物，其所造成的污染和危害已引起普遍关注。有机氯农药一旦进入土壤，就会对土壤造成严重污染，又因为其具有难降解性和易积累性，被生物摄取后极易随食物链进入人体造成慢性中毒。有机氯农药对人类健康和生态系统有较大毒害作用，如神经系统失调、癌症、生殖异常和先天性缺陷等。虽然在80年代中国就已经禁止了有机氯农药的使用，但通过近年来各地区的研究发现，HCHs和DDTs在国内在很多地区的土壤和水体中仍有发现。

Chlorine in organic compounds is referred to as organochlorine. Organochlorine pesticides (OCPs), a type of persistent organic pollutants, have drawn considerable research attention because of the pollution and environmental harm they have caused. Once OCPs enter the soil, the soil is contaminated, and because OCPs are hard to decompose and accumulate, they will enter the human body through the food chain and cause intoxication. OCPs are harmful to both the ecological system and human health, resulting in nervous system disorders, cancer, reproductive abnormalities, and congenital defects. Though the Chinese government banned OCPs in the 1980s, studies in recent years have revealed that HCHs and DDTs were still found in the soil and water in many regions across China.

线虫是一种寄生类病害，难以防治，严重抑制植物生长。温度是影响线虫侵染能力的主要因素之一，但作用机理尚不明确。为探讨线虫抗性机制，以抗、感线虫品种（N、C）为对象，用人工接种，分析3个温度下不同品种根系抗氧化酶活性、组织结构变化规律、抗性基因表达特征。受线虫侵染，不同抗性品种根POD、CAT活性及糖、HRGP含量增加，SOD活性降低，N的POD、CAT活性及糖、HRGP含量高于C。同时，2品种的抗氧化酶活性变幅在25℃最大，35℃最小。不同温度下，N受线虫侵染后根系组织结构无巨型细胞、卵囊，但C出现大量巨型细胞。在25℃，C根系组织巨型细胞数量比15℃、35℃多，而N的木质化程度在25℃较15℃、35℃加重。在不同温度，未接种线虫的N的根系RK基因表达量在各时期无差异。线虫侵染促进N的RK基因上调，表达量在不同温度下在侵染2 d达峰值，25℃、15℃的表达量是35℃的3.36、1.62倍。线虫侵染使感病品种根SOD活性、渗透调节物质含量降低，且木质部出现大量巨型细胞，从而感病。抗病品种在线虫侵染下有较强的ROS清除能力、渗透调节能力，根组织结构无明显变化，RK基因上调表达，利于抵御线虫侵染。与25℃相比，烟在35℃通过提升抗氧化酶活性、保持良好组织结构降低线虫侵染；RK基因在35℃未失活仅表达量下降，仍对线虫侵染产生抑制。

Nematodes are parasitic pests that are difficult to control and severely inhibit plant growth. Temperature is one of the main factors affecting nematode infectivity, but the underlying mechanism of action remains unclear. To explore the nematode resistance mechanism, the antioxidant enzyme activity, tissue structure changes, and resistance gene (Rk) expression characteristics of the roots of different cultivars at three temperatures were analyzed by the artificial inoculation of nematode-resistant and susceptible cultivars (hereafter referred to as N and C). The activity of peroxidase (POD) and catalase (CAT) and the content of sugar and hydroxyproline-rich glycoprotein (HRGP) in the roots of different resistant cultivars increased after nematode infection, while the activity of superoxide dismutase (SOD) decreased. Notably, the activity of POD and CAT and the content of sugar and HRGP in N were higher than those in C. Meanwhile, the activity of antioxidant enzymes in both cultivars varied the most at 25°C and the least at 35°C. There were no giant cells and oocysts in the root tissue structure of N after nematode infection at different temperatures, while a large number of giant cells appeared in C. The number of giant cells in the root tissue of C at 25°C was more than that at 15°C or 35°C, while the degree of lignification in N was more severe at 25°C than that at 15°C or 35°C. In addition, there was no difference in the expression of the Rk gene at different temperatures in the roots of N uninoculated with nematodes, whereas the up-regulated expression of the Rk gene in N was promoted after nematode infection. The expression levels peaked on the 2nd day after nematode infection at different temperatures, and the expression levels at 25°C and 15°C were 3.36 and 1.62 times higher than that at 35°C. The activity of SOD and the content of osmoregulatory substances reduced in the roots of C after nematode infection, and a large number of giant cells appeared in the xylem, resulting in susceptibility. N showed strong reactive oxygen species (ROS) scavenging ability and osmoregulatory ability, no significant changes in root tissue structure, and the up-regulated expression of the Rk gene after nematode infection, which were conducive to resisting nematode infection. Compared with the situation at 25°C, the nematode infection of tobacco was lowered by increasing the activity of antioxidant enzymes and maintaining good tissue structure at 35°C, and the expression of the Rk gene was not inactivated but decreased at 35°C, which still inhibited nematode infection.

地震动作用具有明显的不确定性，目前结构设计中采用多道设防和强柱弱梁设计准则确保结构柱具有足够安全储备与具有一定极限承载延性性能。结构柱是允许进入弹塑性损伤阶段，需要考虑结构弹塑性阶段强化增强承载力与弹塑性变形能力，基于位移的弹塑性变形能力通常用延性指标反映，延性指标是具有非常重要意义，结构是否能震而不倒主要取决于结构柱延性性能。

The great uncertainty in seismic ground motion necessitates the adoption of multi-defense and strong-column-weak-beam design criteria in the structural design to guarantee sufficient safety margin and certain ultimate bearing ductility of structural columns. Since structural columns are allowed to enter the elastoplastic damage stage, it is necessary to consider the strengthening of the bearing capacity and elastoplastic deformation capacity of the structure in the elastoplastic stage. The displacement-based elastoplastic deformation capacity is usually demonstrated by the ductility index, which is of great significance in determining whether a structure can survive in an earthquake.

人员行走与车辆运动时都会对地面施加激励，造成地面介质产生形变或偏离平衡位置，从而产生地震波。地震波主要分为两种，一是实体波，二是表面波。实体波能穿越地球内部，而表面波只能在地表进行传递，其中实体波又分为P波和S波，而表面波分为瑞雷波与勒夫波。P波又称压缩波、疏密波或无旋波，是一种纵波，其介质质点的振动方向与波前进方向平行，在所有地震波中，它的前进速度最快，也是最早到达震中。P波能在固体、液体中传递。其传播方式如图1所示。

Both human footsteps and vehicle movements can pose excitation to the ground, causing deformation of the ground medium or deviation from the equilibrium position, and hence seismic waves. There are two types of seismic waves: real seismic waves and surface waves. The former can penetrate the ground, but the latter only transfers on the ground surface. Real seismic waves include primary waves (P-waves) and secondary waves (S-waves), and surface waves include Rayleigh waves and Love waves. The P-wave, also termed compressional wave, dilatational wave or irrotational wave, is a kind of longitudinal wave. The vibration direction of the medium particles is parallel to the wave’s traveling direction. The P-wave has the fastest traveling speed and can reach the epicenter most quickly among all types of seismic waves. The P-wave can travel in solids and liquids. Figure 1 (a) shows its traveling pattern.

竹炭作为一种性能稳定、廉价易得的吸附材料，被广泛应用。通过磷酸改性可以在竹炭表面形成特定的基团，从而形成定向吸附。本研究采用磷酸质量分数为45%、竹炭粉与磷酸的浸渍比为1：10、活化温度为500℃、活化时间为1.5h的条件对竹炭进行改性，在竹炭表面形成了羟基、羧基和磷酸根。

Bamboo charcoal, an adsorbent, is known to the public due to its stability and availability. Phosphoric acid modification contributes to forming specific functional groups on the surface of bamboo charcoal, thereby enhancing its adsorption capabilities. The modification process in this study involved impregnating the bamboo charcoal in a 45% mass fraction of phosphoric acid solution, using a 1:10 ratio of bamboo charcoal powder to phosphoric acid, and activating it at a temperature of 500°C for 1.5 h. The modification resulted in the formation of hydroxyl, carboxyl, and phosphate groups on the surface of the bamboo charcoal.

为研究液氮应用于开放空间进行火灾扑救的灭火效能，本研究通过AMESim多学科仿真平台构建了液氮射流灭火装置的数值模型，开展了不同输入压力下液氮的质量流量、漏热段温度及气液比例稳定时间的研究，同时搭建了开放空间液氮射流系统的实验装置，分析了实验与仿真结果的偏差，探讨了不同输入压力对系统形成稳定液氮射流状态的影响。

To investigate the fire-extinguishing efficiency of liquid nitrogen in open space, this paper constructs a numerical model of a liquid nitrogen jet fire-extinguishing device through the AMESim multidisciplinary simulation platform, implementing research on the mass flow rate, the temperature of the heat leakage section, and the stabilization time of gas-liquid ratio concerning liquid nitrogen under diverse input pressures. Concurrently, this paper analyzes the deviation between the experimental results and the simulation results through the constructed experimental device of the liquid nitrogen jet system in the open space, thus exploring the impact exerted by different input pressures on the formation of the stable liquid nitrogen jet state of the system.