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排序方式: 共有825条查询结果,搜索用时 15 毫秒
1.
针对页岩气大排量、大砂量压裂后,排采测试流程设备繁多、作业效率低、天然气计量误差大、流程易堵塞等问题,对现有测试流程的设备、计算方法、数据采集系统等进行改进,设计了新型转向功能模块流程和固相物捕捉系统,对比分析了四种天然气产量计算方法,并引入了数据采集系统。通过现场试验表明,该研究成果的应用减少了设备的使用,提高了天然气的计量精度,提高了作业效率,避免了事故的发生,可实现钻塞流程转换、单井测试切换等多项功能,效果显著。  相似文献   
2.
杨帆  臧浩 《中州煤炭》2021,(5):91-96
为研究活动断裂对地质灾害的影响,选取华北板块鲁西地块与苏鲁造山带东界昌邑—大店断裂为研究对象,通过野外面积调查、构造剖面测量、工程地质样品分析测试、综合研究等手段,详细调查了区内活动构造的特征、地质灾害的发育特征,在此基础上讨论了活动断裂对地质灾害影响机制,认为受昌邑—大店构造的影响,地裂缝分布主要沿构造带分布,区内地裂缝成因可以归结为活动构造与胀缩土共同作用下形成的。  相似文献   
3.
为了实现社会经济的可持续发展,切实保护和合理开发利用各类矿产资源、优化矿产资源开发,最大限度地减轻矿业活动对矿山地质环境的污染与破坏,加快矿山地质环境恢复和综合治理已刻不容缓。以都兰县五龙沟金矿岩金沟矿区为研究对象,通过资料收集与分析、野外实地调查、综合研究等方法,对矿山的开采规模、范围、工程等级、工程布置及矿山开采方式等进行了分析,认为地质环境问题主要表现为矿业活动对地形地貌景观破坏、易引发的地质灾害问题、对地表土地的占压和破坏。通过危岩清理,平硐口采取支护、设立挡石墙、斜井回填、弃渣平复、自然恢复、抚育管理等工程手段,达到对矿山地质环境保护与恢复治理。  相似文献   
4.
Despite long-term efforts for exploring antibacterial agents or drugs, potentiating antibacterial activity and meanwhile minimizing toxicity to the environment remains a challenge. Here, it is experimentally shown that the functionality of reduced graphene oxide (rGO) through copper ions displays selective antibacterial activity that is significantly stronger than that of rGO itself and no toxicity to mammalian cells. Remarkably, this antibacterial activity is two-orders-of-magnitude greater than the activity of its surrounding copper ions. It is demonstrated that rGO is functionalized through the cation–π interaction to massively adsorb copper ions to form a rGO–copper composite and result in an extremely low concentration level of surrounding copper ions (less than ≈0.5 µm ). These copper ions on rGO are positively charged and strongly interact with negatively charged bacterial cells to selectively achieve antibacterial activity, while rGO exhibits the functionality to not only actuate rapid delivery of copper ions and massive assembly onto bacterial cells but also result in the valence shift in the copper ions from Cu2+ into Cu+, which greatly enhances the antibacterial activity. Notably, this rGO functionality through cation–π interaction with copper ions can similarly achieve algaecidal activity but does not exert cytotoxicity against neutrally charged mammalian cells.  相似文献   
5.
作为一种特殊的生物源化学物质,生物毒素对农产品、人畜、环境等有不可忽视的健康隐患,但由于其结构与功能作用的多样性,其对于生物化学、医药学、环境生态学等又具有重要意义。本研究就生物毒素的来源分类、危害、脱毒技术及生物毒素的应用进行综述,以期为进一步生物毒素的监管与开发利用提供理论参考。  相似文献   
6.
泾阳县是咸阳市辖县之一,地质构造复杂,大断裂发育,岩土体结构类型较复杂,人类活动强度大,降水量大且集中,地质灾害发育。该文分析了泾阳县地质灾害的类型、规模、发育特征和分布特征,进而分析了地质灾害的形成条件。分析表明,地质灾害发育的控制因素主要有地形地貌、地质构造、地层和岩土体结构、坡体地质结构等,而地下水和植被是地质灾害的影响因素,人类工程活动、大气降雨和地震是地质灾害的促发因素。  相似文献   
7.
The constrained estimation in Cox’s model for the right-censored survival data is studied and the asymptotic properties of the constrained estimators are derived by using the Lagrangian method based on Karush–Kuhn–Tucker conditions. A novel minorization–maximization (MM) algorithm is developed for calculating the maximum likelihood estimates of the regression coefficients subject to box or linear inequality restrictions in the proportional hazards model. The first M-step of the proposed MM algorithm is to construct a surrogate function with a diagonal Hessian matrix, which can be reached by utilizing the convexity of the exponential function and the negative logarithm function. The second M-step is to maximize the surrogate function with a diagonal Hessian matrix subject to box constraints, which is equivalent to separately maximizing several one-dimensional concave functions with a lower bound and an upper bound constraint, resulting in an explicit solution via a median function. The ascent property of the proposed MM algorithm under constraints is theoretically justified. Standard error estimation is also presented via a non-parametric bootstrap approach. Simulation studies are performed to compare the estimations with and without constraints. Two real data sets are used to illustrate the proposed methods.  相似文献   
8.
李波  杨江涛  李伯宣  罗兰  景泽 《矿产勘查》2019,(9):2429-2435
通过物联网技术实现地质灾害各监测要素的物物相连,实现前端报警、无线互联互通功能,建立地质灾害监测预警平台,实现专业监测数据具备部、省、市、县四级信息互联互通的功能实时共享;使监测预警信息实时发送至隐患点防灾责任人、监测责任人和监测人,以指导一线防灾工作高效开展;并在自贡市荣县一匹山崩塌预警过程中取得了重要成效,具有很强的参考价值。  相似文献   
9.
Dietary advanced glycation end products (dAGEs) are complex and heterogeneous compounds derived from nonenzymatic glycation reactions during industrial processing and home cooking. There is mounting evidence showing that dAGEs are closely associated with various chronic diseases, where the absorbed dAGEs fuel the biological AGEs pool to exhibit noxious effects on human health. Currently, due to the uncertain bioavailability and rapid renal clearance of dAGEs, the relationship between dAGEs and biological AGEs remains debatable. In this review, we provide the most updated information on dAGEs including their generation in processed foods, analytical and characterization techniques, metabolic fates, interaction with AGE receptors, implications on human health and reducing strategies. Available evidence demonstrating a relevance between dAGEs and food allergy is also included. AGEs are ubiquitous in foods and their contents largely depend on the reactivity of carbonyl and amino groups, along with surrounding condition mainly pH and heating procedures. Once being digested and absorbed into the circulation, two separate pathways can be involved in the deleterious effects of dAGEs: an AGE receptor‐dependent way to stimulate cell signals, and an AGE receptor‐independent way to dysregulate proteins via forming complexes. Inhibition of AGEs formation during food processing and reduction in the diet are two potent approaches to restrict health‐hazardous dAGEs. To elucidate the biological role of dAGEs toward human health, the following significant perspectives are raised: molecular size and complexity of dAGEs; interactions between unabsorbed dAGEs and gut microbiota; and roles played by concomitant compounds in the heat‐processed foods.  相似文献   
10.
Using a comprehensive set of drop weight impact test data (h50) newly compiled from literature for 308 materials, a recent approach to predict impact sensitivities of nitro compounds is generalized to most explosive substances of interest. Compared to previous ones, this procedure is more thoroughly validated and exhibits a good predictive value. Furthermore, it yields new insight into the physical mechanisms involved, explaining for instance the unexpected desensitization of some oxygen-deficient triazoles upon nitration.  相似文献   
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