高粘性高盐量吹填土固结过程孔隙分维特征

真空预压处理吹填土地基的方法应用广泛,但塑料排水管经常会被吹填土细颗粒堵塞。为提高吹填土造陆效率,通过室内试验,研究了高粘性高盐量吹填土在自重沉淤和加负压联合作用下的固结规律,分析了吹填土取土点的工程地质特征。用易溶盐试验和X射线衍射分析方法确定吹填土中晶体的类型,并结合自重固结不同阶段的扫描电子显微镜微观结构照片,研究吹填土含盐量对排水效果的影响,总结高粘性高盐量吹填土固结排水时渗流通道变化规律。研究发现,随着吹填土含水量降低,晶体颗粒随水流失,渗流通道则处于不断变化的非稳定状态。同时,将分维数作为研究高粘性高盐量吹填土的微观结构指标,发现随着自重固结程度的增加,高粘性高盐量吹填土含水量减少,颗粒表面吸附能力下降,晶体颗粒逐渐脱离土颗粒表面,使土体孔隙和结构单元体颗粒发生规律性变化。     

Polycyclic aromatic hydrocarbon contamination and recovery characteristics in some organisms after the Nakhodka oil spill

Following the oil spill from the Russian tanker Nakhodka in 1997 in the Sea of Japan, polycyclic aromatic hydrocarbons (PAH) were monitored for three years in some molluscs from the Mikuni-cho shore in Japan. Total PAH concentrations in marine organisms except for spiny top shell, ranged from 5.3 to 32.7 ng/g wet weight, but no trends were evident. Total PAH concentration in spiny top shell (Turbo cornutus) was 44 ng/g w.w. in the first month after the oil spill. However, it rapidly decreased to less than 5.4 ng/g w.w. from the second month. Spiny top shell, which was exposed to dietary Nakhodka heavy fuel oil, concentrated benzo(a)pyrene to 17.1 ng/g w.w. after two weeks of exposure and then rapidly eliminated it during an elimination phase. These results suggest that spiny top shell accumulates PAHs because of their low ability to metabolize PAH, but it can excrete parent PAHs rapidly when removed from the source of contamination. Thus it is suitable as an indicator organism in monitoring oil contamination. It can also be inferred from these field and laboratory investigations that, in three years, organisms from the Mikuni-cho shore seem to have adequately recovered from the Nakhodka oil spill contamination.     

Problems with inferring P–T–t paths in low-P granulite facies rocks

Microstructural evidence commonly is used to infer metamorphic reactions, which are used to infer pressure–temperature–time ( P–T–t ) paths. However, this approach in low- P /high- T  (LPHT) granulite facies metamorphic terranes has two main problems. (1) Microstructural evidence may be inconclusive, so that reactions cannot be inferred with confidence. In particular, relative timing of mineral growth inferred from inclusions, moulding relationships and foliation–porphyroblast relationships is commonly ambiguous or invalid. The most reliable indicators of metamorphic reactions are partial pseudomorphs and corona structures, especially if symplectic intergrowths (indicating simultaneous growth of two or more minerals) are involved. (2) Even reactions that can be inferred with confidence do not indicate unique P–T  trends, owing to P–T  slopes of reaction curves. Where successive reactions can be shown to have occurred in the same rock, a line or curve joining reaction-curve intersections gives an apparent single-event path. However, isotopic evidence is needed to prove that polymetamorphism (involving more complex paths making fortuitous intersections with the apparent single-event path) did not occur. Although these problems are well known, their importance is not always emphasized in metamorphic investigations.
The difficulties are illustrated by published work on P–T–t paths for Proterozoic LPHT granulite facies rocks of central Australia and Antarctica. Recent work in Antarctica has shown that P–T–t paths may be episodic and more complex than the simple, single-event paths commonly inferred from microstructural evidence alone.     

工厂化培育海水珍珠的研究

在海区中养殖珍珠常受到台风、淡水、低温等自然灾害的影响和敌害生物的侵袭,使育珠贝大量死亡。在岸上水槽系统,在人为控制的条件下养殖海水珍珠——工厂化育珠,则可避免上述的影响。本文介绍工厂化培育海水珍珠的试验设施、育珠试验、试验结果与评价。     

关于恒星壳层源产生非稳定现象的条件

本文依据A.Weigert讨论恒星内部热核源何时会产生非稳定现象的方法,对壳层源产生非稳定现象(又称热脉动)的条件进行了严格推导。结果表明,当壳层源很薄,其厚度与半径之比小于0.37时,就能产生非稳定条件。     

模拟基坑开挖过程的试验研究

采用三轴剪切试验对基坑开挖过程中土体卸荷的应力路径进行模拟，研究了由于侧向卸荷对土体抗剪强度指标产生的影响，并从土的微观结构角度分析了产生这一现象的原因。试验结果表明，经过侧向卸荷过程土样的抗剪强度指标与常规三轴试验明显不同。     

吹填土沉积后微观结构特征定量化研究

粘性土微观结构是土体的一个重要质量特征.在外界环境条件影响下,吹填土在宏观上所表现出来的各种特性,都是其内在微观结构发生变化的外在反映.因此,微观结构对土的性质变化起着十分重要的作用.本文以连云港地区吹填土为研究对象,对其沉积后微观结构进行了定量测试,获得结构单元体的等效粒径、丰度、定向频率和定向分维数等定量化数据,并对结构单元体大小、平面形态和定向性进行了分析,该研究为吹填土工程性质的评价和改善提供了重要依据.     

Comparative study of microstructural characteristics and stored energy of mechanically activated hematite in different grinding environments

Hematite concentrate was mechanically treated using different milling machines and experimental conditions in air atmosphere. The changes in phase constitution, particles size, specific surface area, lattice parameters and X-ray amorphous phase fraction of activated hematite were determined. It was found that the agglomeration of the particles take place during extended milling with accessible pores for Nitrogen gas. The higher media surface brought about the largest specific surface area whatever milling devices used. After 9 h of grinding with higher media surface, the maximum and minimum specific surface area resulted from the grinding in the tumbling and vibratory mills, accounting for 6.83 m²/g and 18.42 m²/g, respectively. For the same grinding condition, tumbling mill produced the lowest X-ray amorphous phase. The maximum X-ray amorphous material estimated around 85% from the grinding in the planetary mill with higher media surface for 9 h of milling.     

前寒武纪干酪根微结构的高分辨电镜研究

本文根据高分辨电镜观察结果,描述了若干前寒武纪干酪根的微结构,讨论了干酪根微结构与母岩变质作用的关系。发现,在变生和变质过程中,干酪根微结构的变化趋势是不同的;层间距(d_(002))不是H/C比值的线性函数;干酪根的微结构可以指示母岩的变质程度。