浅谈内补外固法在盾构隧洞抢修漏点中的应用

随着许多地下输水隧洞投入使用,隧洞运行安全及突发意外事件下的抢修方法受到水利行业密切关注。北京市南干渠工程地下钢筋混凝土输水隧洞在运行阶段被勘探钻杆打漏,需停水抢修漏点。为确保漏点封堵严密、施工高效、一次成型,采用内补外固法,即洞内修补与洞外加固结合的方法进行修复。采用本方法修复后,钻孔漏点得到有效封堵,隧洞运行恢复正常,且通水后结构未产生任何安全问题。

PPH联合中医外治固脱法治疗直肠内脱垂伴混合痔所致便秘疗效观察

目的:探讨PPH联合中医外治固脱法治疗直肠内脱垂伴混合痔所致便秘的临床疗效。方法:选取2016年1月~2018年1月于我院肛肠科住院接受治疗的IRP伴混合痔致出口梗阻性便秘的患者60例。参照随机数表法将其分成对照组和研究组,每组30例。治疗组行PPH+中医外治固脱法(消痔灵注射术)治疗,对照组单纯行PPH治疗,主要观察两组治疗前后便秘症状评分。结果:两组治疗后症状评分明显低于治疗前,且治疗组下降更显著,P<0.05。治疗组临床总有效率为93.10%,对照组临床总有效率为82.14%,两者比较差异有统计学意义,P<0.05。结论:PPH联合中医外治固脱法治疗直肠内脱垂伴混合痔致便秘疗效优于单纯行PPH术,方法安全有效,值得在临床推广。

中医外治固脱法与PPH术联合应用治疗直肠黏膜内脱垂临床研究

目的:探究分析中医外治固脱法与PPH术联合应用治疗直肠黏膜内脱垂的临床效果。方法:选取直肠黏膜内脱垂患者100例为研究对象,随机分为仅采用PPH术治疗的对照组(50例),与采用中医外治固脱法与PPH术联合应用治疗的观察组(50例),比较两组患者的治疗效果,周便次数、时间和不尽感与并发症发生率等指标。结果:观察组患者治疗的周便次数、时间和不尽感、复发率等指标改善明显优于对照组,且并发症发生率低于对照组;观察组患者总有效率为96.0%,明显优于对照组的80.0%,差异均有统计学意义(P<0.05)。结论:中医外治固脱法与PPH术联合应用治疗直肠黏膜内脱垂的临床效果显著,可改善患者直肠功能,减少并发症的发生率,提高患者满意度,效果确切,值得临床推广应用。

告成矿砌碹交岔点的破坏原因及维修加固

本文通过对砌碹交岔点破坏原因的分析,提出较适应砌碹交岔点维修的方法,即对交岔点采取围岩注浆加固,用“内补外固”法修复。

恐龙骨架化石的陈列展示

人类诞生于数百万年前,形成了自己的文明,成为地球的霸主。而在人类出现之前,地球真正的霸主则是恐龙,那是一个辉煌的恐龙时代。恐龙是地球曾经的统治者,人们从地壳中发现它们并挖掘出来用于研究和展示。形态各异的恐龙骨架是博物馆科普教育的强力展品,因此恐龙化石是各自然类博物馆竞相收藏的展品。博物馆完整装架好的恐龙骨架更能吸引更多的参观者。然而,装架恐龙化石并没有想象中那么简单,恐龙化石装架是一项系统工程,需要利用古脊椎动物学、比较解剖学、古生态学等专业知识,工作者还要有高超的技术才能让不完整的动物化石更加生动形象、栩栩如生地展现给广大观众。

Curing Mechanism of Condensed Polynuclear Aromatic Resin and Thermal Stability of Cured Resin

In order to improve the thermal stability of condensed polynuclear aromatic(COPNA) resin synthesized from vacuum residue, 1,4-benzenedimethanol was added to cure COPNA resin. The curing mechanism was investigated by proton nuclear magnetic resonance spectrometry, solid carbon-13 nuclear magnetic resonance spectrometry and Fourier transform infrared spectroscopy. Microstructures of the uncured and the cured COPNA resins were studied by scanning electron microscopy and X-ray diffractometry. The thermal stability of COPNA resins before and after curing was tested by thermogravimetric analysis. The element composition of the cured COPNA resin heated at different temperatures was analyzed by an element analyzer. The results showed that the uncured COPNA resin reacted with the cross-linking agent during the curing process, and the curing mechanism was confirmed to be the electrophilic substitution reaction. Compared with the uncured COPNA resin, the cured COPNA resin had a smooth surface, well-ordered and streamlined sheet structure with more crystalline solids, better molecular arrangement and orientation. The weight loss process of the uncured and cured COPNA resins was divided into three stages. Carbon residue of the cured COPNA resin was 41.65% at 600 ℃, which was much higher than 25.02% of the uncured COPNA resin, which indicated that the cured COPNA resin had higher thermal stability.

UV enhanced gas–solid synthesis of chlorinated poly vinyl chloride characterized by a UV–Vis online analysis method

Dynamic characteristics of UV enhanced gas–solid PVC chlorination process were revealed by a UV–Vis spectral online analysis method. Experimental results showed an instantaneous increase of the chlorination rate as soon as UV light was affiliated, which demonstrated the intensified effect of UV radiation on PVC chlorination directly.Different affiliation methods of UV light were then studied, proving that continuous UV radiation could enhance the chlorination process significantly while intermittent UV radiation was able to initiate the chlorination reaction once it was conducted. Besides, experiments were carried out to study the influences of parameters on the chlorination process such as UV wavelength, chlorination temperature, partial pressure of chlorine gas and PVC raw materials. Among all the parameters, chlorination temperature and partial pressure of chlorine gas were testified as two key factors to determine the chlorination performance. Thermal analysis of CPVC products showed that their corresponding properties such as the glass transition temperature(Tg) and the homogeneity of chlorine distribution in polymer phase were improved with the increase of chlorine content.

SnO_2-based solid solutions for CH_4 deep oxidation: Quantifying the lattice capacity of SnO_2 using an X-ray diffraction extrapolation method

A series of SnO2‐based catalysts modified by Mn, Zr, Ti and Pb oxides with a Sn/M （M=Mn, Zr, Ti and Pb） molar ratio of 9/1 were prepared by a co‐precipitation method and used for CH4 and CO oxidation. The Mn3＋, Zr4＋, Ti4＋and Pb4＋cations are incorporated into the lattice of tetragonal rutile SnO2 to form a solid solution structure. As a consequence, the surface area and thermal stability of the catalysts are improved. Moreover, the oxygen species of the modified catalysts become easier to be reduced. Therefore, the oxidation activity over the catalysts was improved, except for the one modified by Pb oxide. Manganese oxide demonstrates the best promotional effects for SnO2. Using an X‐ray diffraction extrapolation method, the lattice capacity of SnO2 for Mn2O3 was 0.135 g Mn2O3/g SnO2, which indicates that to form stable solid solution, only 21%Sn4＋cations in the lattice can be maximally replaced by Mn3＋. If the amount of Mn3＋cations is over the capacity, Mn2O3 will be formed, which is not favorable for the activity of the catalysts. The Sn rich samples with only Sn‐Mn solid solution phase show higher activity than the ones with excess Mn2O3 species.

In Vitro Biossay for Assessing Estrogenic Activity of Sewage Treatment Works

The estrogenic activity of influents and effluents of five municipal sewage treatment works （STWs） in Nanjing was investigated. The water samples were enriched by solid phase extraction, then eluted with different polar solvents, and f＇mally three fractionated extracts were obtained. Estrogen receptor recombinant yeast screen was used to evaluate the estrogenic activity of individual fractionated extracts and their mixture. The results show that the influents and effluents of the two STWs mainly receiving industrial wastewater have no obvious estrogenic activity, and the water samples from the other three STWs mainly receiving domestic wastewater show different degrees of estrogenic activity. The total estrogenic concentration ranged from 171. 52 ng/L EEQ （E2 - equivalent concentration） to 1 008.37 ng/L EEQ in the influents, and from ND （not detected） to 36.3 ng/L EEQ in the effluents. By comparing the results of different fractionated extracts, the methanol and dichloromethane extracts of the water samples show higher estrogenic activity, while the hexane extracts very low. The （xeno）estrogens from domestic wastewater could be removed obviously by activated sludge treatment units. However, the effluents of STWs in Nanjing still have chemical contaminants capable of binding to estrogen receptors.