Use of Support Vector Regression Based on Mean Impact Value Model to Identify Active Compounds in a Combination of Curcuma longa L.and Glycyrrhiza extracts

A support vector regression based on the mean impact value (MIV) model was constructed to identify the bioactive compounds inhibiting proliferation of HeLa cells in a combination of turmeric (Curcuma longa L.) and liquorice (Glycyrrhiza) extracts. The quantitative chemical fingerprint from 50 batches of turmeric and liquorice extracts was established using high performance liquid chromatography hyphenated to an ultraviolet visible detector. Qualitative results were obtained using ultra performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry. A total of 46 peaks (peaks 1–15 from turmeric and 16–46 from liquorice) were selected as “common peaks” for analysis. The inhibitory effect of the combined extracts on HeLa cells was measured by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. It was found that 15 compounds (peaks: 8, 12, 30, 24, 46, 11, 14, 9, 3, 1, 44, 18, 7, 45 and 43) possessing high absolute MIV exhibited a significant correlation with the cytotoxicity against HeLa cells; most of these have already been confirmed with potential cytotoxicity in previous research. The important potential application of the present model can be extended to help discover active compounds from complex herbal medicine prior to traditional bioassay-guided separation. It is considered that this could be a useful tool for re-developing herbal medicine based on the use of these active compounds. © 2017, Tianjin University and Springer-Verlag Berlin Heidelberg.

Prediction of Henry Constants and Adsorption Mechanism of Volatile Organic Compounds on Multi-Walled Carbon Nanotubes by Using Support Vector Regression

Support vector regression （SVR） combined with particle swarm optimization for its parameter optimization is employed to establish a model for predicting the Henry constants of multi-walled carbon nanotubes （MWNTs） for adsorption of volatile organic compounds （VOCs）. The prediction performance of SVR is compared with those of the model of theoretical linear salvation energy relationship （TLSER）. By using leave-one-out cross validation of SVR test Henry constants for adsorption of 35 VOCs on MWNTs, the root mean square error is 0.080, the mean absolute percentage error is only 1.19~, and the correlation coefficient （R2） is as high as 0.997. Compared with the results of the TLSER model, it is shown that the estimated errors by SVR are ali smaller than those achieved by TLSER. It reveals that the generalization ability of SVR is superior to that of the TLSER model Meanwhile, multifactor analysis is adopted for investigation of the influences of each molecular structure descriptor on the Henry constants. According to the TLSER model, the adsorption mechanism of adsorption of carbon nanotubes of VOCs is mainly a result of van der Waals and interactions of hydrogen bonds. These can provide the theoretical support for the application of carbon nanotube adsorption of VOCs and can make up for the lack of experimental data.

Electronic Effect of Carbon Support on Pt Catalyst Supported on Graphite Intercalation Compound

Graphite intercalation compounds（GIC） were tested as an experimental model for studying the electronic effect of carbon support on the catalytic activity and poisoning tolerance of Pt catalyst for direct methanol fuel cells. The GIC samples with different intercalation degrees were prepared by electrolyzing graphite flake in H2SO4 for varying the periods of time. The GIC-supported Pt catalyst was deposited electrochemically. The catalytic activity and poisoning tolerance of the GIC-supported Pt catalysts were evaluated. It was found that GIC with sulfate anion as intercalate was able to catalyze methanol electrooxidation, which could be related to the positive charges generated on the graphite layer upon intercalation. As intercalation degree increased, the catalytic activity of the GIC-supported Pt catalyst decreased while the poisoning tolerance improved. This suggests that electron donation from support to catalyst had great effect on both catalytic activity and poisoning tolerance of Pt catalyst. And intercalation can be adopted as another important way to make modification on carboneous catalyst support.

Bolt Supporting of Large-Span Soft Rock Roadway in Shaqu Colliery

The instability of trapezoidal Ⅰ-steel support is analysed for the compound roof of main coal seam in Shaqu Colliery, and the mechanism of bolt supporting is studied. A scheme of bolt supporting has been given and put into practice, remarkable technical and economic benefits have been got.

SYNTHESIS AND CHARACTERIZATION OF A SILICA-SUPPORTED CARBOXYMETHYLCELLULOSE PLATINUM COMPLEX AND ITS CATALYTIC BEHAVIORS FOR HYDROGENATI0N OF AR0MATICS

A silica-supported carboxymethylcellulose platinum complex (abbreviated as SiO_2-CMC-Pt) has been prepared and characterized by XPS. Its catalytic properties for hydro-genation of aromatic compounds were studied. The results showed that this catalystcould catalyze the hydrogenation of phenol, anisol, p-cresol, benzene and toluene to cyclo-hexanol, cyclohexyl methyl ether, p-methyl cyclohexanol, cyclohexane and methylcyclo-hexane, respectively in 100% yield at 30℃ and 1 atm. In the hydrogenation of phenol,COO/Pt ratio in SiO_2-CMC-Pt has much influence on the initial hydrogenation rate andthe selectivity for the intermediate product, cyclohexanone. The highest initial rate andthe highest yield of cyclohexanone both occur at COO/Pt ratio of 6. The complex is stableduring the reaction and can be used repeatedly.

A Simulation Study of Support Break-Off and Water Inrush during Mining under the High Confined and Thick Unconsolidated Aquifer

The thick Cenozoic unconsolidated aquifer is deposited under Sunan syncline core in Huaibei coalfield, the water yield property of unconsolidated bottom aquifer is strong and water pressure is high in some areas (up to 4 MPa in some areas). Water inrush accident often occurs during mining under unconsolidated aquifer, the biggest characteristic is abnormal mine pressure and support break-off during water inrush accident comparing with normal condition. In order to study mechanism of?support break-off and water inrush during mining under the high confined thick unconsolidated aquifer, a simulation of similar material was designed. The experimental results indicated that, under normal condition, the compound breakage sequence of water-resisting key strata between coal seam and high confined thick unconsolidated aquifer is from top to bottom and the basic reason of synchronous fracture is the load of bottom key strata increased suddenly when the breakage of top key strata happened. Because of high confined thick unconsolidated aquifer, surface acts on the bottom key strata soil layer in the form of uniformly distributed load, which is the load-transfer mechanism of confined thick unconsolidated aquifer. Once the overlying key strata compound breaks, the height of unstable strata will reach far more than 30 meters and exceed support capability of current fully-mechanized mining supporter, which leads to support break-off accident during mining process under confined unconsolidated aquifer.

非均相催化剂催化臭氧氧化含酚废水的研究进展

催化臭氧氧化技术在深度处理含酚有机废水方面具有操作简单、氧化效率高、二次污染小等优点。然而,其规模化应用依赖于开发高活性和高稳定性的非均相催化剂。介绍了催化臭氧氧化技术中非均相催化臭氧氧化反应机理。从非负载型和负载型催化剂两方面综述了催化臭氧氧化酚类化合物非均相催化剂的研究现状,重点分析了非负载型催化剂、单活性组分负载型催化剂及多组分负载型催化剂的特点及局限性,指出多组分负载型催化剂由于具有显著提升臭氧利用率、降低臭氧投放量,以及性能可优化潜力大等优势,是当前主要研究对象。针对高效催化剂开发,提出了从几何结构和电子结构角度入手,实现催化剂组分、尺寸和缺陷位调控等性能优化策略。最后对用于酚类化合物去除的非均相催化剂的研究进展进行了总结和展望,以期对催化臭氧氧化技术中高效催化剂的开发提供参考。

木质素衍生酚类化合物催化加氢脱氧制备液体燃料研究进展

生物质中的木质素衍生酚类化合物具有含氧量高、稳定性差等缺点,通过加氢脱氧反应提质可以制备高品质生物液体燃料,对双碳目标的实现有重要的现实意义。综述了近年来用于木质素衍生酚类化合物反应的金属负载型催化剂,首先从单金属和双金属组分的角度分析金属间协同效应对加氢脱氧反应性能的影响。然后,针对金属位点特性对加氢脱氧反应的影响,讨论金属粒度、金属分散度和单原子金属催化剂的催化活性,阐明金属位点特性的影响因素,及其对加氢脱氧反应机理的影响机制。随后,基于载体对金属位点的影响,探讨载体特性与金属位点特性的关联因素,揭示载体对金属活性位点的影响机制。最后,对金属负载型催化剂的发展方向进行展望。

全功能自承式电缆支架的研究

利用传统电缆支架进行电缆敷设会产生涡流损耗和安装工期长等问题,影响工程进度和电缆的运行安全。研制了一种全功能自承式电缆支架,其选用阻燃型热固性高分子复合材料作为支架,具有质量可靠、耐腐蚀等优点;采用高强度弹簧抱箍的自承式结构,使支架牢固地支撑在工作现场,并且便于灵活地进行电缆敷设。研究结果表明,支架可以显著提高施工速度、降低人工和设备成本,具有较高的应用价值。

复合地层中盾构施工掘进参数相关性及预测研究

在盾构掘进过程中,众多掘进参数交织在一起,规律错综复杂。科学地分析这些参数之间的规律与相关性,对于盾构的实时控制至关重要。依托济南地铁R2左线工程,基于机器学习方法对复合地层中盾构施工的掘进参数进行研究。首先,分析地层参数与盾构掘进参数之间的关系,通过相关性分析发现,6个掘进参数中,盾构的总推进力和刀盘扭矩与其他参数的相关性尤为显著。然后,利用支持向量机算法,对不同地层中盾构总推进力和刀盘扭矩进行预测。预测结果与实际监测结果基本一致,证明这种方法的有效性。最后,为进一步提高预测精度,采用PSO算法对盾构掘进参数预测模型进行优化。优化后的模型总推进力R2提升约3%,刀盘扭矩R2提升约10%,优化效果十分显著。该项研究可为复合地层中盾构施工参数选择提供重要参考。

深埋冲击区域大跨度岔门顶板复合支护技术

工作面切眼大跨度岔门支护是煤矿顶板管理的重中之重。随着煤矿开采逐步向深部方向发展,受地质构造、采空区、埋藏深度等诸多因素影响,冲击地压危险区域巷道支护条件越来越复杂,给大跨度岔门顶板支护带来了较大难度。结合姚桥煤矿矿井自然条件,在满足冲击地压支护标准的条件下,对工作面切眼大跨度岔门顶板采取了复合支护加固技术,取得了较好的应用效果。

负载型烯烃氢甲酰化催化剂研究进展

对负载型配合物催化剂、负载型纳米粒子催化剂以及负载型单原子催化剂的研究进展及其在烯烃氢甲酰化制醛反应中的应用进行了综述,对通过调变载体性质、助剂种类、活性组分粒径等方式改善负载型催化剂的性能进行了分析,并对烯烃氢甲酰化催化剂的研究方向进行了展望。指出降低催化剂中金属Rh的含量,提高负载型催化剂的性能,并将它们应用到工业生产中,是当下和未来的努力方向。

炭黑品种对缺气保用轮胎支撑胶性能的影响

采用3种不同牌号的炭黑分别搭配不同并用比的NR/BR,设计性能侧重点分别为机械强度、耐屈挠性能和生热性能的支撑胶配方,研究其对缺气保用轮胎零气压耐久性能的影响。结果表明:成品轮胎的零气压耐久性能与支撑胶的硬度和刚性相关性较强;在不同的胶料硬度水平下,支撑胶的耐屈挠性能和生热性能未表现出对成品轮胎零气压耐久性能的明显增益效果。

德顺煤业复合顶板巷道围岩控制技术研究

为解决矿井开采顶板支护难、支护效果不佳等问题,基于山西焦煤西山煤电德顺煤业11106工作面复合顶板岩层及锚杆锚索支护情况,利用FLAC3D数值模拟软件,建立复合顶板岩层及锚杆支护模型,模拟给锚杆施加不同预紧力,探究复合顶板岩层强度、稳定性、完整性情况,模拟结果表明:高预应力锚杆支护作用较强,增强了围岩的自承载能力。基于模拟结果,采取长短锚索支护方式对11106工作面顶板进行支护,监测发现顶板稳定性较好,现场实践取得了良好效果。

软土基坑设计若干关键问题探讨及基坑设计实例应用分析

珠三角地区的软土具有含水量大、压缩性高、承载力低等特性,这对基坑工程的设计和施工都提出了更高的要求,因此软土深基坑在复杂环境下的支护设计已成为岩土工程的一个新课题。针对软土基坑的特殊性,本文探讨软土基坑设计的4个关键问题:(1)采用增量法分析支护结构的受力和变形过程;(2)考虑锚杆或锚索等的预应力作用时,预应力使基坑主动侧的土体受压,因此主动侧土体应该等效成弹簧,弹簧是否参与作用要根据结构的位移来判断;(3)当放坡开挖存在软弱下卧层地基时,不仅要验算其整体稳定性,还应验算地基的稳定性或承载力;(4)针对双排桩支护结构的受力和变形的研究,还存在许多问题有待进一步完善,结合具体工程,提出双排桩简化计算方法。很多软基工程事故也说明,这几个关键问题如果没有被考虑和重视,则基坑存在安全隐患。最后,以2个软土深基坑设计为案例,以上述的几个关键问题的解决方法为理论支撑,验证其合理性,并详细分析软土深基坑采用多种支护形式的设计方案,为类似工程提供指导。

空间遥感器大口径反射镜的复合支撑结构

针对空间遥感器反射镜对支撑功能的需求,设计了一种应用于空间领域的大口径反射镜复合支撑结构。该复合支撑结构包括A框加切向拉杆的周边支撑和3组whiffletree结构组成的背部支撑。研究了复合支撑的支撑原理和工程实现。基于功能分配和指标分配的理念设计了复合支撑结构。采用有限元分析的手段对设计结果进行了静力学和动力学仿真验证,然后对实际的支撑系统进行了相关的试验测试。试验结果表明,采用复合支撑的反射镜组件在工作状态下的面形精度优于λ/50(λ=632.8nm),镜体刚体位移小于0.01mm,镜体转角小于2″,质量小于50kg。整个组件模态分布合理,基频为161Hz,远高于设计要求的120Hz。各项仿真和测试结果均表明该复合支撑效果良好,满足空间遥感器对可靠性和稳定性的需求。

复合支持向量机方法及其在光谱分析中的应用

SVC和SVR是支持向量机研究的两个主要问题。文章把两种建模方法相结合,先由SVC模型判别分类,后由各类的局部SVR模型进行定量分析,提出了复合支持向量机(CSVM)方法。根据71个试验小区的水稻冠层高光谱与叶片含氮量建立定量分析模型,考证了CSVM算法。基于模拟研究的思想,随机划分建模集和预测集,比例为55∶16。经过5次划分试验,复合支持向量机方法建模对叶片含氮量的预测值与凯氏定氮实际值之间的平均相关系数为0.89,平均绝对误差为0.088;而传统的支持向量机方法得到的平均相关系数为0.87,平均绝对误差为0.091。由此可见,复合支持向量机方法相对于传统的支持向量机方法预测精度有所提高。文章研究方法的提出为化学计量学定量分析研究给出了新的思路。

Multi-KNN-SVR组合预测在含氟化合物QSAR研究中的应用

为深入认识含氟农药生物活性与其结构之间的关系,建立了理想的QSAR模型,从化合物油水分配系数等7个分子结构描述符出发,基于支持向量回归(SVR)和MSE最小原则,经自动寻找最优核函数和非线性筛选描述符,构建了多个K-最近邻(KNN)预测子模型.再经非线性筛选获得保留子模型,以保留子模型实施组合预测(Multi-KNN-SVR).33种含氟化合物对5种不同病害生物活性的留一法组合预测结果表明,采用非线性筛选描述符和KNN子模型能有效地提高预测精度,基于多个KNN子模型的非线性组合能进一步提高预测性能.Multi-KNN-SVR组合预测在QSAR以及其它相关预测研究中具有广泛应用前景.

软岩巷道复合支护技术实践及其效果分析

"三软"煤层成为林南仓矿主采煤层后,如何进行支护设计,选择合理有效的支护形式,减缓巷道变形,减少巷道维修量已成为影响林南仓矿发展的重点问题。文章以林南仓矿为例,介绍了架棚与锚网联合支护技术在软岩巷道中的应用。这种主动支护与被动支护相结合方式能够有效地阻止软弱围岩随时间逐渐劣化,保持巷道在较长时间的稳定。通过多种检测手段,获得了巷道变形、围岩破坏范围和锚杆受力分布状态。监测结果表明,采用软岩巷道复合支护技术成功地解决了林南仓软岩巷道的支护问题。