紫金山东南矿段成矿期次、阶段浅析

通过对紫金山东南矿段铜钼(金)矿床地质矿化特征分析,指出铜钼矿化带主要赋存于花岗闪长斑岩的内外接触带,处于似斑状花岗闪长斑岩的上部,金矿化带赋存在表生氧化带的英安玢岩、隐爆角砾岩中。经过对矿石的组构特征、矿物生成顺序等特征分析,将矿床的成矿演化过程分为斑岩热液期、高硫化浅成低温热液期、表生氧化期三个主要矿化期次,进一步将斑岩热液期分为黑云母-钾长石化阶段、石英-绢云母化阶段、碳酸盐化阶段三个阶段;高硫化浅成低温热液期分为地开石化阶段、明矾石化阶段、硅化阶段三个阶段。研究结果为进一步研究矿床成因提供了依据。     

多模态影像学检查在诊断早期强直性脊柱炎骶髂关节疾病中的效果

目的:探究在早期强直性脊柱炎骶髂关节疾病诊断中不同放射影像学检查方法的应用效果。方法:抽取2018年5月-2020年1月本院收治的早期强直性脊柱炎骶髂关节疾病患者65例作为研究对象,所有患者均开展X线、CT、MRI影像学检查,对比三种不同影像学检查方法的检出率、影像学特征。结果:X线、CT、MRI检出率分别为38.46%(25/65)、60.00%(39/65)、76.92%(50/65),检出率相比,MRI、CT明显高于X线,P<0.05;X线、CT、MRI影像学特征,发现关节间隙出现不同的异常,如关节面出现侵蚀、骨质囊变现象,关节面下骨质出现硬化与关节软骨出现肿胀,其中MRI、CT检查,阳性率高于X线,P<0.05。而对于软组织肿胀、骨髓水肿、滑膜炎症、关节滑膜增厚等现象,只能通过MRI检查才能诊断。结论:在早期强直性脊柱炎骶髂关节疾病诊断中,X线、CT、MRI影像学检查均具有一定的指导意义,而MRI不仅可以提高检出率,还能准确反映微小病灶及其软组织病变,对于早期发现骶髂关节炎值得推荐。     

新发展阶段中国水资源安全保障战略对策

进入新发展阶段，中国水资源安全保障需要以“节水优先、空间均衡、系统治理、两手发力”治水思路为指导，厘清问题、研判趋势、优化对策，支撑新阶段水利高质量发展。本文在全面分析我国水资源安全保障存在的突出问题与面临形势基础上，阐述了新发展阶段中国水资源安全保障的基本思路与战略路径，从保证资源安全、构建国家水网、强化供水保障、建设美丽河湖、改善水环境质量等方面提出了战略对策和需要进一步回答的重大问题，以期为完善新发展阶段中国水资源安全保障战略，全面提高国家水资源安全保障能力提供有力支撑。     

Influence of bunch maturation and chemical precursors on acrylamide formation in starchy banana chips

The present study investigated the effect of ripening stages and chemical precursors on acrylamide formation in deep-fried chips of five plantains and one cooking banana. The highest level of acrylamide was found in the cooking banana, followed by False Horn plantain and French plantain, respectively. French plantain hybrids exhibited a significantly lower (P < 0.05) level of acrylamide when compared to French plantain. The ripening stage demonstrated a positive Pearson correlation (P < 0.05, r = 0.57) with acrylamide formation. As ripening progressed, the levels of glucose and fructose significantly increased (P < 0.05) and showed a positive correlation with acrylamide formation (r = 0.85 and 0.96, respectively). The level of the amino acid asparagine during ripening was not correlated with acrylamide formation. In contrast, the level of histidine, arginine, iso-leucine and cystine during ripening was positively correlated (P < 0.05, r > 0.60) with acrylamide formation in fried chips. The higher level of TP was significantly related (P < 0.05) to the lower level of acrylamide (r = −0.62). The reduced levels of carotenoid isomers, except lutein, during fruit ripening were positively correlated (P < 0.05) with acrylamide formation, especially trans-BC (r = 0.72) and 9-cis-BC(r = 0.64).     

两次喷射对正丁醇部分预混燃烧影响的试验研究

在一台改造的单缸柴油机上进行了预主喷两次喷射策略对正丁醇部分预混燃烧影响的试验研究。研究结果表明:正丁醇燃料实现部分预混燃烧相对汽油燃料对喷射时刻较敏感,最大压力升高率高,稳定运行范围窄,但未燃碳氢、氮氧化物和碳烟排放较低;预主喷两次喷射能有效降低正丁醇部分预混燃烧最大压力升高率,随着预主喷间隔的增大,最大压力升高率先快速降低后上升,预喷射比例越大,获得最低压力升高率对应的预主喷间隔越大;通过优化预主喷两次喷射策略,能显著改善正丁醇部分预混燃烧可控性差、最大压力升高率高的问题,从而有利于实现更大工况范围内的高效燃烧。     

往复式活塞压缩机中间喷液制冷系统的(火用)分析

通过对往复式活塞压缩机进行改造，在单级活塞压缩系统的基础上搭建了一种中间喷液冷却的准两级压缩系统并在蒸发温度为-20 ℃的工况下进行实验测量，根据实验数据对单级活塞压缩系统和新型中间喷液冷却活塞压缩系统的COP、〖HT5”，7”〗火〖KG-*3〗用〖HT5”〗损失和〖HT5”，7”〗火〖KG-*3〗用〖HT5”〗效率进行计算。结果表明：加入中间喷液冷却系统后，系统的COP由1.27提升至1.36，单位制冷量由155.1 kJ/kg提升至176.7 kJ/kg；单级活塞压缩系统〖HT5”，7”〗火〖KG-*3〗用〖HT5”〗损失较大的部分是压缩机和膨胀阀，分别占压缩机输入〖HT5”，7”〗火〖KG-*3〗用〖HT5”〗的16.2%和14.8%，加入中间喷液冷却系统后压缩机部分的〖HT5”，7”〗火〖KG-*3〗用〖HT5”〗损失明显降低，仅占压缩机输入〖HT5”，7”〗火〖KG-*3〗用〖HT5”〗的3.6%，冷凝器及膨胀阀的〖HT5”，7”〗火〖KG-*3〗用〖HT5”〗损比也有所下降。     

Stable isotope and fatty acid compositions of monovarietal olive oils: Implications of ripening stage and climate effects as determinants in traceability studies

The quantitative variability of isotopic and fatty acid compositions in extra virgin olive oil was investigated in relation to variety, olive ripeness index and geographical origin. The study was carried out in two environments of Umbria region (central Italy), differing in annual/seasonal temperatures and rainfalls. Significant correlation was found between oil isotope compositions and climatic seasonal changes during fruit ripening. Moreover, significant isotopic differences among cultivars were related to the period of maximum oil accumulation in the fruits and to the fatty acid profile. A carbon kinetic isotopic effect could be associated with the fatty acid elongation from palmitic to stearic acid and to the unsaturation step leading from oleic to linoleic. No correlation was found between stable isotope and fatty acid compositions during fruit ripening. The analyzed cultivar and ripening effects on oil traceability issues are discussed in order to focus the resolution power of stable isotope methodologies and the possibility to distinguish monovarietal oils from the same area.     

Disseminated tuberculosis: A neglected entity in immunocompromised hemodialysis patients

End‐stage renal disease is considered a factor predisposing to increased risk of tuberculosis with frequent extrapulmonary localization. Although extrapulmonary tuberculosis has been observed for decades, disseminated tuberculosis, a major cause of morbidity and mortality in immunocompromised hosts, remains rather neglected. We report an unusual case of an immunocompromised patient with a late diagnosis and delayed treatment of genitourinary tuberculosis that subsequently led to the diagnosis of vertebral and miliary tuberculosis (disseminating tuberculosis). Therefore, increased awareness is warranted from physicians dealing with hemodialysis patients in order to avoid delays in diagnosis and treatment initiation.     

Two stage stochastic bilevel programming model of a pre-established timberlands supply chain with biorefinery investment interests

This work studies the supply allocation problem, using a Stackelberg game, for an established timberlands supply chain with an additional decision of new biorefinery investments. In a timberlands system, harvester and manufacturer decision makers have separate objectives to maximize their respective profits. This interaction is represented with a turn based Stackelberg game. The harvesters decide first on the quantity harvested, and the manufacturers decide on how much to utilize. This game is modeled with a bilevel mathematical program. The novel feature of this paper's bilevel formulation is the inclusion of parametric uncertainty in a two stage model. The first stage problem involves logistical decisions around biorefinery investments, such as location and capacity, while the second stage problem involves a bilevel timberlands model with parameter uncertainty. Studying this problem formulation revealed interesting insights for solving multiperiod problems with bilevel stages as well as the decision maker's behavior for the timberlands model.