金刚烷类化合物的热稳定性研究及其地质意义

金刚烷类化合物由于其强抗热降解的能力对揭示深层油气藏的地化信息具有重要价值。对金刚烷类化合物热稳定性和裂解演化规律的研究较少,制约了金刚烷类化合物指标的实际应用。选择3种典型的金刚烷化合物(单金刚烷、1,3-二甲基单金刚烷和双金刚烷)作为模型化合物,分别开展金刚烷类化合物单体的黄金管封闭体系裂解动力学实验,以此揭示金刚烷类化合物的热稳定性和裂解演化规律。结果显示:单金刚烷和1,3-二甲基单金刚烷具有相似的热稳定性,均在Easy Ro值为1.5%时发生裂解,而双金刚烷具有更高的热稳定性,在Easy Ro值达到1.8%时才发生裂解,它们的裂解产物包括以甲烷为主的气态烃、以萘系列化合物为主的芳烃和其他同笼状单元数的金刚烷类化合物;当Easy Ro值分别小于2.1%、2.5%和2.5%时,单金刚烷、1,3-二甲基单金刚烷和双金刚烷的单体C同位素组成几乎不变。以上结果表明,金刚烷类化合物的热稳定性与分子结构中笼状单元的数目有关,分子结构中所带的甲基不会明显影响其稳定性;金刚烷类化合物的单体C同位素组成在较宽的成熟度范围内不变,可以用来示踪烃源。研究结果可为新的金刚烷类化合物指标的建立和应用提供实验依据和理论基础。

学龄前儿童弱视的发生现状及其危险因素分析

目的分析学龄前儿童弱视的发生现状及其危险因素。方法回顾性分析2019年4月至2021年5月于本院行视力测试的800名学龄前儿童的临床资料,根据其是否患弱视分为弱视组(n=45)与视力正常组(n=755)。收集800名学龄前儿童的临床资料,采用多因素Logistic回归分析法分析学龄前儿童弱视的危险因素。结果两组年龄、性别比较差异无统计学意义;弱视组母亲妊娠年龄及吸烟史、饮酒史、近亲近视史者占比均高于视力正常组,孕次、产次均多于视力正常组,孕龄短于视力正常组,差异有统计学意义(P<0.05)。多因素Logistic回归分析结果显示,母亲妊娠年龄大、孕龄短、孕次多、产次多、有吸烟史、有饮酒史、有近亲近视史是学龄前儿童发生弱视的独立危险因素(OR>1,P<0.05)。结论学龄前儿童患弱视的风险较高,母亲妊娠年龄大、孕龄短、孕次多、产次多、有吸烟史、有饮酒史、有近亲近视史均为学龄前儿童患弱视危险因素,临床可据此给予指导,以降低学龄前儿童弱视的患病风险。

腹腔镜直肠癌根治术后吻合口瘘的危险因素

目的探讨腹腔镜辅助直肠癌根治术(Dixon术)后吻合口瘘发生的危险因素及手术体会。方法回顾性分析山西医科大学第一医院普外科2014-06至2018-06收治的146例腹腔镜辅助直肠癌根治术患者的资料,分析术后吻合口瘘的危险因素。结果 13例(8. 90%)患者发生吻合口瘘,其中男10例,女3例。术前白蛋白水平低于35 g/L、肿瘤下缘距肛门距离<7 cm、术中使用直线切割闭合器数量超过2个的患者术后吻合口瘘发生率分别高于术前白蛋白水平≥35 g/L、肿瘤下缘距肛门距离≥7 cm、术中使用直线切割闭合器≤2个的患者(P=0. 013、P=0. 037、P=0. 011)。多因素分析,术前白蛋白水平(OR=4. 092,95%CI:1. 231～13. 602)、术中使用闭合器数量(OR=4. 272,95%CI:1. 285～14. 202)是吻合口瘘的独立危险因素。结论术前低白蛋白水平、肿瘤下缘距肛门距离<7 cm、术中使用直线切割闭合器数量大于2个是腹腔镜辅助直肠癌根治术后吻合口瘘的危险因素,患者合并其中一种或多种情况时应当引起注意并采取必要的预防措施。

儿童异常瞬目相关因素的病例对照研究

目的探索异常瞬目儿童的相关危险因素。方法随机选取厦门市妇幼保健院2020年7—12月因异常瞬目就诊的患儿70例,进行问卷调查及相关临床检查,收集资料进行分析比较。结果病例组儿童中屈光不正、偏食、过敏、长时间用眼的比例均高于对照组,差异有统计学意义(P<0.05)。病例组儿童中基础泪液分泌量较对照组减少,差异有统计学意义(P<0.05)。病例组儿童中泪膜破裂时间较对照组缩短,差异有统计学意义(P<0.05)。多因素非条件logistic回归分析结果显示儿童异常瞬目的相关危险因素为:偏食(OR=2.731,95%CI:1.094,6.817),过敏(OR=4.023,95%CI:1.628,9.938),长时间用眼(OR=3.922,95%CI:1.769,9.693)。结论儿童异常瞬目是多因素造成的,与偏食、过敏、长时间用眼有相关性,治疗时应综合考虑。

儿童眼病筛查方法在群体儿童眼保健中的效果

目的分析儿童眼病筛查方法在群体儿童眼保健中的效果。方法选择于2019年3月至2019年12月的9872名儿童作为本次研究的对象,将所有儿童均进行常规观察以及儿童眼病筛查法,对比两种检查方式的准确率以及敏感性。结果在9872名儿童中,正常儿童有7861名,诊断为异常的儿童有2011例,其中利用儿童眼病筛查方法诊断的漏诊率2.29%要低于常规观察法漏诊率75.83%,儿童眼病筛查方法的敏感性97.71%要高于常规观察法的敏感性24.17%,差异均有统计学意义(P<0.05)。结论在群体儿童的眼保健中,利用儿童眼病筛查方法能够有效提高检查的敏感性,同时能够降低漏诊率,从而可以取得一个较好的检查结果。

前处理方法对原油中金刚烷化合物定量的影响

利用色谱/质谱/质谱方法分析了准噶尔盆地不同密度原油中金刚烷化合物的含量,探讨了族组分分离法和直接进样法2种前处理方法对金刚烷化合物测定的影响。族组分分离法会造成原油中金刚烷类化合物含量损失,特别是密度相对小的单金刚烷类损失更大,但族组分分离方法有利于低熟原油中低含量、受挥发作用影响较小的双金刚烷类化合物的富集,更有利于仪器检出。族组分分离法对金刚烷异构化指标影响较小,对应用更为重要的浓度指标影响较大,因此在进行金刚烷类化合物分析时应尽量避免复杂的前处理,减少金刚烷类化合物的损失。选择直接进样法是测定正常油、轻质油和凝析油中金刚烷类化合物的最佳前处理方法,对于部分低熟原油样品可考虑使用族组分分离法进行处理。

白云凹陷烃源岩分布与油气源差异性分析

针对白云凹陷烃源岩的类型和分布特征争议大,主力烃源岩及成藏贡献不明,不同区带油气分布差异性极大的问题,本研究通过对该区文昌及恩平期沉降速率分析,结合已钻井油-气-岩有机地球化学特征与不同母质类型源岩黄金管高温高压生成天然气模拟实验产物特征,认为白云凹陷发育半深湖、浅湖及海相/海侵3类烃源岩,白云主洼及白云西洼的洼陷区(沉降速率>200 m/Ma)可能发育规模性半深湖-深湖相源岩,斜坡-隆起区低沉降速率区(<200 m/Ma)文昌组及恩平组发育浅湖相源岩;白云主洼东部恩平组晚期发育海相/海侵泥岩。文昌组浅湖-半深湖相源岩为该区主力气源岩,而斜坡带中-低沉降速率区文昌组及恩平组浅湖相源岩为主力油源岩,海相/海侵源岩未见成藏贡献,呈现“二源供烃”格局。另外,根据烃源岩生排烃史、断裂体系发育等成藏要素及天然气生烃动力学建模,探讨了白云凹陷中浅层及洼陷内中深层气源及成藏特征差异性;认为隆起区已发现的中浅层气藏隶属于凝析油伴生气含气系统,为干酪根裂解气成藏;洼陷内深层气藏隶属于油裂解气含气系统,为洼陷内因缺乏油源断裂沟通疏导未经排出的原油裂解生气,为超压驱动、致密层阻隔的油裂解气成藏。

基于网络药理学与分子对接技术探讨益气解毒通络方治疗肝硬化的潜在机制

目的基于网络药理学方法及分子对接技术探讨益气解毒通络方(YQJDTLF)治疗肝硬化的作用靶点及信号通路,预测其潜在作用机制。方法基于TCMSP数据库提取YQJDTLF的有效活性成分及作用靶点,通过Drugbank、OMIM、TTD、DisGeNET获取肝硬化治疗靶点,筛选共同靶点;使用Cytoscape软件构建“药物有效活性成分-疾病靶点”可视化调控网络图,利用STRING数据库构建蛋白互作网络图(PPI),然后运用Cytoscape对PPI进行核心蛋白的筛选;最后,通过Metascape对核心靶点进行基因本体(GO)功能富集分析和KEGG通路富集分析,最后完成分子对接。结果共获得93个有效活性成分,135个共同靶点;主要活性化合物包括槲皮素、黄芩素、豆甾醇等;KEGG通路富集分析得出135条通路,涉及癌症信号通路(pathways in cancer)等通路;通过分子对接发现关键中药成分与关键靶点之间的结合活性良好。结论YQJDTLF具有多成分、多靶点、多通路的作用特点,可通过调节相关通路与靶点起到治疗肝硬化的作用。

考虑黏压效应的风电齿轮热弹流分析

在线接触热弹流润滑的基础上,考虑黏压效应,对风电行星轮系齿轮副进行热弹流润滑数值分析,并采用热弹流润滑数值方法和ISO/TS 6336-22计算了齿轮副的最小油膜厚度、安全系数和闪温温度,并比较各主要啮合点的压力和油膜厚度分布。结果表明:与使用ISO/TS 6336-22计算的结果对比,采用热弹流润滑理论计算的油膜更厚,但安全系数更小;在风电齿轮副热弹流润滑分析时应考虑压力对黏度的影响;风电主齿轮箱齿面因啮合产生油膜厚度随温度增加会迅速降低,最小油膜厚度会随载荷增加迅速减小,因此风电齿轮箱要保证足够的润滑,并尽量避免在高于额定载荷下长时间持续运行。

大兆瓦风电齿轮箱动力学模型的响应标定与修正

可靠的动力学仿真模型是振动改善的重要手段。以5.2 MW风电齿轮箱台架传动链动力学模型为例,以行业内的经验建模方法为基础,对动力学建模、响应评估与标定做了阐述。基于灵敏度优化方法对齿轮啮合动力学模型进行修正。最终修正后动力学模型的振动响应准确度较好,表明本文中的经验建模方法结合灵敏度优化方法,可建立比较可靠的动力学模型,是一种有效方法。

Decomposition Temperature of Cold Seep Carbonate and its Relationship with Delta Carbonate

Delta carbonate （Delta C, AC） method is a commonly- used surface geochemical exploration method for petroleum surveys. Delta C holds that light hydrocarbon gases leak into near-surface soils or sediments from underlying petroleum accumulations, then partly oxidized to CO2, resulting in a special carbonate precipitation, which is termed as Delta carbonate （△C）.

不同手术方式治疗慢性肛裂疗效评价的网状Meta分析

目的评价不同手术方式治疗慢性肛裂的效果。方法通过计算机检索传统肛裂切除术、纵切横缝法、改良纵切横缝术、肛裂切除术+外括约肌切开术、肛裂切除术+内括约肌切开术5种手术治疗慢性肛裂的国内外临床研究,采用Stata13及GeMTC软件对其治愈率和并发症发生率进行传统Meta分析和网状Meta分析。结果共纳入21项临床研究2 430例患者。网状Meta分析显示肛裂切除术+内括约肌切开术和肛裂切除术+外括约肌切开术的治愈率均高于传统肛裂切除术,OR值分别为2.27(95%CI=1.14～4.36)、3.26(95%CI=1.67～6.75)。在并发症的发生率方面,纵切横缝术、传统肛裂切除术排前两位,肛裂切除术+内括约肌切开术最低。结论在5种常见的慢性肛裂手术方式中,肛裂切除术+内括约肌切开术的疗效和并发症发生均优于传统肛裂切除术、纵切横缝法、改良纵切横缝术、肛裂切除术+外括约肌切开术。

海洋表层沉积物及其非水解有机质级分对菲和壬基酚的吸附

选择5个南海表层沉积物及其非水解有机质(NHC)级分作为研究对象,应用元素分析、二氧化碳和氮气吸附技术及X射线光电子光谱(XPS)表征,同时研究了其对菲和壬基酚的吸附行为.沉积有机质的有机碳含量与吸附能力之间存在显著的正相关关系,表明沉积有机质在吸附疏水性有机污染物(HOCs)过程中的重要作用.同时,沉积有机质的吸附能力和微孔体积之间也存在显著的正相关,表明微孔填充机理在菲和壬基酚的吸附中扮演着重要角色.此外,NHC级分的表面羧酸碳含量与其对菲和壬基酚的吸附能力之间存在显著的正相关,表明沉积有机质与π供体之间存在较强的π-π电子供受体作用.本研究综合考虑了沉积有机质和HOCs间的多种作用机理(疏水作用、微孔填充和π-π电子供受体作用),有助于进一步理解沉积有机质与有机污染物之间的吸附机制,对于水环境的治理与修复具有重要意义.

Mass balance calculation of the pyrolysates generated from marine crude oil:A prediction model of oil cracking gas resources based on solid bitumen in reservoir

Oil cracking gas plays an important role in the resources of natural gas in the basins with high and over mature marine source rocks in China. The prediction of the oil cracking gas resources becomes nec-essary and urgent in the gas exploration in these basins. A marine crude oil sample was pyrolyzed using sealed gold tubes system. The pyrolysates including gas,liquid and solid were quantitatively analyzed. Based on the pyrolysis data and kinetic calculation,the yield correlativity among gas,liquid and solid products was regressed with high correlative coefficients to establish a prediction model suitable for the resource estimation of oil cracking gas. The verification formula for this model was also established on the principle of mass conservation. The affecting factors and the application precondi-tions of this prediction model were discussed. This model would enlighten and provide some new ideas for the resource assessment of natural gas in the high and over mature marine carbonate source rock areas in China. It is expected to be valuable in gas exploration.

季铵盐接枝聚膦腈微球的制备及抗菌活性

细菌感染引起的疾病问题在世界范围内引起广泛的关注。抗生素虽然能有效治疗细菌感染,但是不合理的使用及滥用会导致细菌产生耐药性。因此,解决细菌耐药性问题并研发出安全高效的非抗生素抗菌剂显得尤为迫切。通过在生物可降解型环交联型聚(环三膦腈-共-聚乙烯亚胺)微球(PHP)表面上接枝环氧丙基十二烷基二甲基氯化铵(DDEAC),成功制备了环交联型聚(环三膦腈-共-聚乙烯亚胺)接枝季铵盐微球(PHPD)。采用FTIR、XPS、TG、TEM和FESEM对微球的结构与形貌进行了表征分析,并研究了其抗菌活性和细胞毒性。实验结果表明,改性抗菌微球PHPD(50μg/mL)对大肠杆菌(E.coli)和金黄色葡萄球菌(S.aureus)的抗菌率均达97.3%。复合材料克服了单独使用季铵盐DDEAC材料的高毒性缺陷,并且在实现高效抗菌的同时也具有很好的细胞相容性。因此,本研究对于开发安全高效的纳米抗菌剂具有一定的指导意义。

The effect of volatile components in oil on evolutionary character- istics of diamondoids during oil thermal pyrolysis

On the basis of the results of simulation experiments, now we better understand the contribution of high carbon number hydrocarbons to diamondoid generation during thermal pyrolysis of crude oil and its sub-fractions(saturated, aromatic, resin, and asphalene fractions). However, little is known about the effect of volatile components in oil on diamondoid generation and diamondoid indices due to the lack of attention to these components in experiments. In this study, the effect of volatile components in oil on diamondoid generation and maturity indices was investigated by the pyrolysis simulation experiments on a normal crude oil from the HD23 well of the Tarim Basin and its residual oil after artificial volatilization, combined with quantitative analysis of diamondoids. The results indicate that the volatile components(≤n C12) in oil have an obvious contribution to the generation of adamantanes, which occurs mainly in the early stage of oil cracking(Easy Ro<1.0%), and influences the variations in maturity indices of adamantanes; but they have no obvious effect on the generation and maturity indices of diamantanes. Therefore, some secondary alterations e.g., migration, gas washing, and biodegradation, which may result in the loss of light hydrocarbons in oil under actual geological conditions, could affect the identification of adamantanes generated during the late-stage cracking of crude oil, and further influence the practical application of adamantane indices.

Use of brGDGTs in surface geochemical exploration for petroleum —A case study of oil and gas fields in the Jiyang depression

Branched glycerol dialkyl glycerol tetraethers(brGDGTs),likely produced by bacteria in soil and peat,are widely distributed,easily detected,newly adopted biomarker compounds.In this study,brGDGTs were used to explore the relationship between the absolute abundance of brGDGTs and the distribution of oil and gas fields in the Duoshiqiao area of the Jiyang depression.The results showed that the concentrations at the Xiakou fault and in the oil and gas fields were obviously higher than those in the contrast areas.The clear relationship among the concentration of brGDGTs,the distribution of oil and gas fields,and the acidolysis hydrocarbon(ethane)indicates that the concentration effectively responds to hydrocarbon seeps from the oil and gas field below.brGDGTs may become some of the most important indicators in surface geochemical prospecting for oil and gas.

Determination of carbon isotopic composition of individual light hydrocarbons evolved from pyrolysis of source rocks by using GC-IRMS

The carbon isotopic composition of individual light hydrocarbons generated from source rocks that had been pyrolysed in vacuum glass tube were determined by using the GC-IRMS techniques. The results indicate that abundant CO2 in the pyrolysates has a remarkable effect on the determination of CH4δ13C. Running cryogenically with an initial temperature of -40℃ can effectively eliminate the effect. In addition, it conduces to measuring the δ13C of C2+ hydrocarbons by increasing the injection volume and/or absorbing CO2 with the solution of sodium hydroxide. The above measures will help to get the carbon isotopic composition of C1-C7 components, which is of great significance for gas/source rock correlation and for study on the genesis of natural gas.

Integration of LNG Regasification Process in Natural Gas-Fired Power System with Oxy-Fuel Combustion

Oxy-fuel combustion power systems can utilize the cold energy released during the liquefied natural gas(LNG)regasification to reduce the power consumption of CO_(2) capture,but the specific LNG cold energy consumption of CO_(2) capture is still too large.To recover more CO_(2) with the limited LNG cold energy at a low energy cost,a novel natural gas-fired oxy-fuel power system with the cascade utilization of LNG cold energy is proposed in this work,where the LNG cold energy could be sequentially utilized in the air separation unit and the CO_(2) recovery process.The new system is evaluated with the Aspen Plus software.The results show that the net electrical efficiency and the specific primary energy consumption for CO_(2) avoided(SPECCA)of the new system are comparable to those of the chemical looping combustion cycle,and superior to those of the conventional O_(2)/CO_(2) cycles.Moreover,the specific LNG needed for CO_(2) avoided(SLNCC)of the new system is more than 67.2%lower than the existing oxy-fuel power systems utilizing the LNG cold energy.Furthermore,it is found that the O_(2) purity of 97.0 mol.%and the CO_(2) capture ratio of 97.0%are optimal conditions,because the SPECCA,the specific exergy consumption for CO_(2) avoided(SECCA)and the SLNCC are at the minimum of 1.87 GJLHV⋅t_(CO_(2))^(−1),2.60GJ⋅t_(CO_(2))^(−1) and 1.88tLNG⋅t_(CO_(2))^(−1),respectively.Meanwhile,the net electrical efficiency and the exergy efficiency of the new system reach 51.51%and 49.23%,respectively.

Cross-layer optimization in ultra wideband networks

Ultra wideband （UWB） network brings both chance and challenge to personal area wireless communications. Compared with other IEEE 802 small range wireless protocols （such as WLAN and Bluetooth）, UWB has both extremely high bandwidth （up to 480 Mbpa） and low radiation. Moreover, the structured MAC layer of UWB is the fundamental difference to WLAN. The top one is that only when two UWB devices belong to the same piconet can they communicate with each other directly, which means that we must jointly consider topology formation and routing when deploying UWB networks because the interaction between routing and topology formation makes separate optimization ineffective. This paper tries to optimize UWB network from a cross-layer point of view. Specifically, given device spatial distribution and traffic requirement, we want to form piconets and determine routing jointly, to maximize the overall throughput. We formulate the problem of joint optimization to mixed-integer programming and give a practical lower bound that is very close to the theoretical upper bound in our simulation. Furthermore, our lower bound is much better than an algorithm that only considers topology formation in UWB networks.