DAMAGE MODEL OF CONTROL FISSURE IN PERILOUS ROCK

Hitherto, perilous rock is the weakest topic in disasters studies. Specially, damage of control fissure under loads is one key technique in study of develop mechanism of perilous rock. Damage division of end area of control fissure was defined by authors, then calculation methods of timed-Poisson＇s ratio and timed-Young＇s modulus were established in damage mechanics theory. Further, the authors set up damage constitutive equation of control fissure, which founds important basis to numerical simulation for control fissure to develop.

Method to calculate fatigue fracture life of control fissure in perilous rock

Rupture and safety of perilous rock are dominated by control fissure behind perilous rock block. Based on model-Ⅰ and model-Ⅱ stress strength factors of control fissure under acting of weight of perilous rock, water pressure in control fissure and earth- quake forces, method to calculate critical linking length of control fissure is established. Take water pressure in control fissure as a variable periodic load, and abide by P-M criterion, when control fissure is filled with water, establish the method to calculate fatigue fracture life of control fissure in critical status by contributing value of stress strength factor stemming from water pressure of control fissure in Paris＇s fatigue equation. Further, parameters （C and m） of sandstone with quartz and feldspar in the area of the Three Gorges Reservoir of China are obtained by fatigue fracture testing.

Synthesis of the Prospective Anticancer Molecule Perillic Acid from Orange Essential Oil by the Yeast <i>Yarrowia lipolytica</i>

The bioconversion of the hydrophobic and volatile limonene to perillic acid, a potential anticancer agent, by the yeast Yarrowia lipolytica was studied in two steps. Firstly, experimental design was used for process optimization using high-purity limonene as substrate and secondly orange essential oil containing 89.1% limonene was used as substrate under the previously optimized conditions. Limonene concentration and pH were identified by fractional factorial design as significant factors and were optimized by central composite design. Under optimized process conditions (0.16% (v/v) limonene;pH 6.9), the 24 h biotransformation process resulted in the accumulation of 0.368 g·L-1 of perillic acid corresponding to a molar yield of 23.1%. A subsequent substrate addition under the same reaction conditions doubled perillic acid concentration to 0.793 g·L-1 and a molar yield of 24.2%. The use of orange essential oil under the optimized reaction conditions increased both perillic acid accumulation and yield to 0.872 g·L-1 and 29.7%, respectively. The robustness of Y. lipolytica allowed the efficient biotransformation of a crude by-product of the citrus industry into a valuable fine chemical.

Determination of Perillic Acid in Bioconversion Supernatants by Gas Chromatography

Perillic acid can be obtained from microbial oxidation of the exocyclic methyl group of limonene. Due to the pharmacological potential of such a metabolite, the biotransformation processes leading to its synthesis have been approached in recent studies. A robust analytical method is needed to assess the performance of such studies. An analytical method was developed and validated to determine perillic acid in the supernatants of a yeast-induced bioconversion of limonene, involving gas chromatography (GC) and an acid-induced precipitation during the sample preparation. GC analysis was performed using a column with polyethylene glycol as stationary phase (HP-Innowax) which resulted in higher loads and better peak shape. The sample preparation involved the supernatant initial filtration and precipitation with 0.6 M HCl followed by centrifugation and dissolution in ethyl acetate. GC analysis conditions were oven from 50°C to 250°C at 20°C·min-1, and then held 5 min (total runtime 15 min). Injector was set at 280°C, and detector at 300°C. Helium was the carrier gas at 1 ml·min-1. Injections of 1.0 μl were at the split ratio 25:1. The method was validated: Linearity with R2 of 0.9992, Accuracy of 98.3% in the range 190 - 950 μg·ml-1;Limit of detection of 10.4 μg·ml-1;Repeatability of 2.1% RSD. Thus, a complete methodology to determine perillic acid in a bioconversion supernatant was developed and validated. This overall approach may be useful for bioconversions of monoterpenes by other microorganisms that metabolize limonene.

Study on Sinking-Sliding Failure Mechanism of Perilous Rock at Wangxia in Three Gorges of the Yangtze River, China

The giant perilous rock at Wangxia (named Wangxia perilous rock) is representative in Three Gorges of the Yangtze River, China, has threatened badly the navigation of the Yangtze River channel for a long period. The giant perilous rock is composed of siliceous limestone and argillaceous limestone, and includes two elements marking by W1 and W2, respectively. The W1 is an isolated pillar while the W2 is in clintheriform. The linking segment of dominant fissure in the W2 is composed by moniliform solution funnels at its back, and the locked segment of the dominant fissure at the base of the W2 is composed by two parts. For the locked part of the dominant fissure of the W2, the upper segment shows the same lithology with the perilous rock and it can be simplified as an elastic medium, for the lower segment composed by argillaceous shale and mudstone can be simplified as a strain-softening medium. Introducing the water-softened function, the constitutive curves with two kinds of medium materials for the locked segment in the dominant fissure of the W2 have been proposed. Based on energy principle, the cusp catastrophe model for perilous rock rupture is built and formulas for the transient elastic and impulsive acceleration and the elastic-impulsive velocity of perilous rock catastrophe rupture have been established. By the calculation, the elastic-impulsive acceleration for the catastrophe rupture of the W2 is 531.4 m/s2, while the average elastic-impulsive velocity is 2.608 m/s. Further, it is deduced that the elastic-impulsive velocity at the base of the W2 is about 5.2 m/s. For the transient ruture of the W2, there is a greater speed difference between the top and the base of the W2, which impels the giant perilous rock to be retroverted sliding rupture, coinciding with the fact. Undoubtedly, studies in this paper must play an important role to analyze the catastrophe rupture mechanism of giant perilous rocks at both banks in Three Gorges of the Yangtze River, China.

The Haunting“Yellow Peril”

In modern times,whenever China, the giant that had been abused and humil-iated by the West for more than a century, awoke and barely started to stand up,the clamor of the“Yellow Peril”rose in the West. Invariably such nonsense wastime and again refuted by the righteous voice.

“YELLOW PERIL”—A HOAX THEN AND NOW

Frenzied cries of“China threat”have once again cropped up in the West,withsome people in the US media shouting the loudest at a time when we are on thedawn of a new century.These gentlemen fly in the face of historical truth and al-lege that a resurgent China is posing a threat to its Asian neighbors and US.

Dynamic Stability and Fuzzy Reliability Analysis of Toppling Perilous Rock Under Seismic Excitation

To predict the occurrence of the collapse disaster in toppling perilous rock under the action of bidirectional earthquakes,the dynamic stability and fuzzy reliability calculation method of toppling perilous rock under the action of bidirectional earthquakes is proposed.First,the mass viscoelasticity model is used to simulate two main control surfaces of toppling perilous rock,the seismic dynamic response model and motion equation of toppling perilous rock are established based on the D'Alembert principle,and the Newmark-β method is used to solve the dynamic motion equation.Then,the instability event of toppling perilous rock is considered a fuzzy event,the membership function expression of the stability coefficient of toppling perilous rock is determined based on the fuzzy failure criterion,the calculation equations of the toppling perilous rock dynamic stability coefficient and fuzzy reliability are established,and the fuzzy reliability evaluation method based on the probability distribution of reliability is proposed.Finally,the influence of different superposition modes of seismic excitation on the fuzzy reliability of toppling perilous rock is analyzed.The calculation results of toppling perilous rock in the engineering case show that the fuzzy reliability calculated after considering the fuzzy failure criterion is reduced by 10.73% to 25.66% compared with the classical reliability.Considering the bidirectional seismic excitation,the fuzzy reliability of toppling perilous rock is reduced by 5.46% to 14.89%.Compared with using the acceleration peak time encounter mode to superpose the seismic excitation,the fuzzy reliability of toppling perilous rock is reduced by 3.4% when the maximum action effect time encounter mode is adopted.

考虑消落带岩体劣化影响的典型危岩岸坡稳定性研究

三峡库区周期性水位升降引起的消落带岩体劣化对典型危岩岸坡稳定性具有重大影响。基于野外调研及地勘资料,采用通用离散单元法程序(universal distinct element code,简称UDEC)研究了消落带劣化区形态对近水平层状高陡危岩岸坡的稳定性影响。研究表明:目前三峡库区巫山段的近水平层状危岩岸坡消落带岩体劣化严重,在不同消落带劣化区存在紧密层状、松散碎裂状、溶蚀凹腔状、含挤压碎裂带等典型消落带劣化区形态;含有第1种消落带劣化区形态的危岩岸坡稳定性较好,危岩体位移较小,失稳模式为滑移破坏;含有第2种消落带劣化区形态的危岩岸坡危岩体先向坡内偏移,其后随着消落带岩体支撑强度弱化向坡外倾倒破坏;含有第3种消落带劣化区形态的危岩岸坡危岩体向坡外位移较大,失稳模式为倾倒破坏;含有第4种消落带劣化区形态的危岩岸坡稳定性主要受挤压破碎带的力学性质控制,易产生沿破碎带切割面的旋转滑移破坏;通过对以上4种劣化区形态的危岩岸坡增加防治加固措施,危岩体的变形位移得到了不同程度的有效控制。

南宋沿海地区巡检与海患治理

巡检司是宋代为缉拿走私、平息基层变乱、维持地方治安而在各地增设的机构,其主管官的称谓很复杂,简称“巡检”。随着海外贸易的兴盛,南宋时期沿海地区各类走私猖獗,走私者分布广、规模大,海上盗贼势力空前强大,负责缉私与巡查盗贼的巡检数量随之增加。沿海巡检所统领的土兵是当时基层常备巡警力量,根据缉私对象、寇盗活动规模及其治理难易程度的不同,或与附近巡检寨兵联合行动,或配合水军等主力官兵及地方民防力量协同参与弹压行动,在近海海患治理中发挥重要的基础性作用。揭示南宋沿海各地巡检的布局特征,分析其职能变化,探讨巡检在当时海患治理机制中的地位和作用,对于深化和推进地方治理机制的相关研究有重要的意义。

老河口市红层边坡崩塌危岩体运动轨迹及冲击能量分析

本文以汉丹铁路沿线切坡形成的陡崖边坡为研究对象,分析危岩段的边坡特征,对危岩体特征进行分类,运用Rockfall软件模拟滚石崩落轨迹,综合预测滚石冲击能量,对老河口地区及同类型红层边坡变形破坏的防治具有指导意义及参考价值。研究表明:区内多数落石的最大水平运动距离在15m左右,最远运动距离接近32m,沿线危岩体直接威胁平台处的汉丹铁路和下方居民建筑安全,不威胁S302省道及省道过往行人和车辆;建议加强沿线专业监测,局部辅以喷浆防护。

岩腔深度对危岩失稳机制的影响分析

为研究岩腔深度对危岩体失稳机制的影响,采用3D打印技术制备4种危岩理想概化模型,开展冰冻试验,结合数字图像相关(digital image correlation,DIC)方法对危岩破坏全程进行非接触式、实时变形观测。基于DIC计算得到的全场变形数据,从精细化角度定量分析主控节理面相对位移演化规律和危岩失稳破坏机制。研究结果表明:岩腔型危岩失稳机制与岩腔深度密切相关,当岩腔深度小于危岩体宽度时,危岩体表现为旋转张拉破坏;当岩腔深度等于危岩体宽度时,危岩体表现为拉剪破坏。此外,危岩体失稳时间具有随岩腔深度的增加而缩短的规律。研究结果可为量化揭示危岩体失稳机制提供1种新的思路。

西汉东越海事史的“揭阳”“海风波”

汉武帝时代,东越参与汉朝远征南越的海上进军,却中途退兵,其理由是海路航行的严重危难,史称“以海风波为解”。这是史籍第一次以“风波”言海难威胁。考察战事发生的季节,不排除台风灾害的可能。以“风波”记述航海遭遇的风浪之灾,汉代还有其他史例。关于海上丝绸之路交通,也有“苦逢风波溺死”的记载。军事史所见“伏波”名号,应当与克服“海风波”有关。“海”“风波”或说“海风波”,也成为后世史书记述海事的语言习惯。

巴万高速典型边坡危岩分析与处治方法研究

随着国民经济的快速发展,跨山区的高速交通愈发受到重视,而山区地质灾害频发,边坡危岩属于山区的典型地质灾害,因此,山区高速公路尤其需要做好边坡危岩的处治工作。基于此,本文对边坡危岩的失稳方式进行了讨论,并根据巴万高速某边坡危岩工程实例,提出采用柔性主动防护网技术与静态膨胀破碎法相结合的施工方案进行边坡危岩处治,并对该方案的工艺流程进行了介绍,为同种类型的边坡危岩处治提供了思路。

Footpath Perils

one of the things that drives me I nuts about China is parking on ’ footpaths. I nearly got knocked down recently on what will be my last visit to the historic old Maizidian Street. Here the local government

Perils of a Post-Olympic Slump

The seven-year run-up to the Olympics has seen China’s white-hot economy chug along with an annual growth rate of more than 10 percent. But the global economic race is more of a marathon than a sprint. Several former Olympic host countries, including Japan and Australia, suffered economic slumps to varying degrees after the euphoria. Now eyes are turning to China to see if the Games will have a similar impact after they end. Will a post-Olympic slowdown play out here, or could it even prompt another economic take-off in the country? China Development Observation, a business monthly, interviewed Chen Jian, Executive Director of the Beijing Olympic Economy Research Association; Li Yining, a renowned economist; and Zhuang Jian, a senior economist at the Asian Development Bank China Resident Mission, for some answers.

The Pleasures and Perils of Scientists in Industry

《科学家》杂志的一项统计表明,在公司里工作的科学家非常重视公司的正直、诚信以及工作氛围。然而,随着公司的发展,公司财政压力加大,公众期望值增高,科学家们也体会到诸多压力。另外,企业领导和科学家之间的关系紧张,科学家并不为公司所重视,他们对某些特殊试验的质疑和忠告也未能为公司领导所采纳和接受。

“黄祸论”:一个帝国主义的政治修辞

“黄祸论”是19~20世纪之交出现的帝国主义政治话语,是西方列强对自身基于强权得到的利益有可能丧失的恐惧的表征。本文梳理了这一政治话语的产生及其在经济和政治上的意味,考察了无政府主义者巴枯宁在陈述“黄祸论”时不同于资本主义的逻辑,最后概观了中国舆论和知识人对“黄祸论”的批判,指出“黄祸论”不过是帝国主义之间博弈的修辞,与中国无关。

作为“唤醒国民”的实践:民国时期报刊辟谣及其内在逻辑探析

民国时期,针对政治类谣言、经济类谣言、娱乐类谣言、社会类谣言,670家报刊运用多种方式进行了辟谣,在此过程中呈现出了三种辟谣话语:解释性辟谣话语、教育性辟谣话语、规范性辟谣话语。上述辟谣话语和辟谣实践背后,潜藏着一种内在逻辑:民国时期报刊辟谣,不仅是处于成长期的中国报人和报刊事业建构现代民族国家“新民”和“共意”基础的话语实践,也是“救亡图存”“前途选择”的“唤醒国民”的实践。由此可见,民国时期的报刊辟谣实践,不仅承载着民国时期新闻事业的历史责任,也体现着时代特色。