Study on the in situ desulfurization and viscosity reduction of heavy oil over MoO_(3)–ZrO_(2)/HZSM-5 catalyst

Heavy oil is characterized by high viscosity.High viscosity makes it challenging to recover and transport.HZSM-5,MoO_(3)/HZSM-5,ZrO_(2)/HZSM-5 and MoO_(3)–ZrO_(2)/HZSM-5 catalysts were developed to promote in situ desulfurization and viscosity reduction of heavy oil.The physical and chemical properties of catalysts were characterized by XPS,XRD,TEM,NH3-TPD,etc.The effects of temperature,catalyst type and addition amount on viscosity and composition of heavy oil were evaluated.The results showed that the presence of MoO_(3)–ZrO_(2)/HZSM-5 nanoparticles during aquathermolysis could improve the oil quality by reducing the heavy fractions.It reduced viscosity by 82.56%after the reaction at 280℃ and catalyst addition of 1 wt%.The contents of resins and asphaltic in the oil samples were 5.69%lower than that in the crude oil.Sulfur content decreased from 1.45%to 1.03%.The concentration of H2S produced by the reaction was 2225 ppm.The contents of sulfur-containing functional groups sulfoxide and sulfone sulfur in the oil samples decreased by 19.92%after the catalytic reaction.The content of stable thiophene sulfur increased by 5.71%.This study provided a basis for understanding the mechanism of heavy oil desulfurization and viscosity reduction.

Effects of sports on school adaptability, resilience and cell phone addiction tendency of high school students

BACKGROUND Sport help promote healthy physical and mental development of high school students.To date,there have been few studies on the effect of sport on school adaptability,resilience and cell phone addiction tendency of high school students.AIM To explore the effects of sports on school adaptability,resilience and cell phone addiction of high school students.METHODS A stratified random sampling method was used to select 600 students from two high schools in Lhasa,and Physical Activity Rating Scale,School Adjustment Scale for High School Students,Chinese Adolescents Resilience Scale,and Mobile Phone Addiction Index were used for field questionnaire survey.RESULTS Sport was positively correlated with school adaptability and resilience(P<0.01),school adaptability was positively correlated with resilience(P<0.01)and cell phone addiction was negatively correlated with sports,school adaptability and resilience(P<0.01).The direct effect of sport on cell phone addiction was significant(P<0.001),accounting for 20.51%of the total effect.The mediating effect of school adaptability on sport and cell phone addiction was significant(P<0.001),accounting for 17.38%and 35.36%of the total effect value,respectively.School adjustment and resilience had a significant chain-mediated effect on sport and cell phone addiction(P<0.001),accounting for 26.75%of the total effect.CONCLUSION Sport affected the cell phone addiction tendency of senior high school students through the mediating effect of school adaptability and resilience,and through the chain mediation effect of both.

瑞芬太尼与舒芬太尼靶控输注对老年患者行腹腔镜胃癌根治术麻醉恢复质量的影响

目的比较靶控输注瑞芬太尼和舒芬太尼对老年患者行腹腔镜胃癌根治术麻醉恢复的质量。方法选取2016年9月-2018年12月该院腹腔镜胃癌根治术患者84例,随机分为舒芬太尼组(n=42)和瑞芬太尼组(n=42)。两组患者应用靶控输注舒芬太尼和瑞芬太尼为基础的麻醉。记录并比较两组患者唤醒时间、拔管时间、定向力恢复时间、生命体征、应激反应、T细胞亚群分布及不良反应发生率。结果两组患者定向力恢复时间差异无统计学意义(P>0.05)。舒芬太尼组的清醒和拔管时间明显短于瑞芬太尼组,差异均有统计学意义(P<0.05)。舒芬太尼组麻醉结束、麻醉诱导后和麻醉前的心率(HR)、平均动脉压(MAP)和脉搏血氧饱和度(SpO2)比较,差异均无统计学意义(P>0.05),而瑞芬太尼组麻醉结束、麻醉诱导后和麻醉前的HR、MAP和SpO2比较,差异均有统计学意义(P<0.05)。舒芬太尼组在麻醉后、麻醉结束、麻醉结束24 h和麻醉结束72 h 4个时间点,血葡萄糖(GLU)、皮质醇(Cor)、白细胞介素-6(IL-6)和C反应蛋白(CRP)的浓度均明显低于瑞芬太尼组,CD3^+、CD4^+和CD8^+及CD4+/CD8^+明显高于瑞芬太尼组,瑞芬太尼组麻醉不良反应发生率明显高于舒芬太尼组,差异有统计学意义(P<0.05)。结论对于接受腹腔镜胃癌根治术的老年患者,靶控输注舒芬太尼为基础的麻醉具有麻醉过程平稳、应激反应小、抑制细胞免疫轻和不良反应少等优点,值得临床推广。

Physical model of fluid flow characteristics in RH-TOP vacuum refining process

To understand the characteristic of circulation flow rate in 250-t RH-TOP vacuum refining process, the 1：4 water model test was established through the bubble behavior and gas holdup in the up-leg to investigate the effects of different processes and equipment parame- ters on the RH circulation flow rate. With the increases of lifting gas flow rate, liffing bubble travel, and the internal diameter of the up-leg, and the decrease of nozzle diameter, the work done by bubble floatage and the circulation flow rate increase. The expression of circulation flow rate was derived fi＂om the regression analysis of experiment data. Meanwhile, the influences of vacuum chamber pressure and nozzle blockage situation on the circulation flow rate were discussed in detail by the bubble behavior and gas holdup in the up-leg. It is necessary to maintain a certain vacuum chamber liquid level in the molten steel circulation flow. Compared with a nozzle with symmetrical blockage in the up-leg, when a nozzle with non-symmetrical blockage is applied, the lifting gas distribution is non-uniform, causing a great effect on the molten steel circulation flow and making the circulation flow drop largely.

Study on the mechanism of hydrodesulfurization of tetrahydrothiophene catalyzed by nickel phosphide

Hydrodesulfurization(HDS)reaction can significantly reduce the viscosity and sulfur content of heavy oil,while the HDS reaction mechanism of tetrahydrothiophene as the main sulfide in heavy oil is still unclear.The HDS experiment of tetrahydrothiophene catalyzed by nickel phosphide(Ni_(2)P)is carried out at 200-300°C.The results indicate that the H_(2)S production under the catalysis of Ni_(2)P increases obviously within 200-250°C.The main gas products of HDS reaction are butane,butene and H_(2)S.Meanwhile,the mechanism of tetrahydrothiophene catalyzed by Ni_(2)P is analyzed based on Density Functional Theory(DFT).It is revealed that the adsorption model is most stable when tetrahydrothiophene is vertically adsorbed on the V-Ni-Hcp1 site of Ni_(2)P(001).The C-S bond is elongated and the C-C bond is shortened after adsorption.Hydrogenation(HYD)is the most possible reaction route of tetrahydrothiophene on Ni_(2)P(001)surface.There are two routes with the lowest activation energy,which are C_(4)H_(8)S→C_(4)H_(8)SH^(*)→C_(4)H_(9)SH^(*)→C_(4)H_(10)+H_(2)S and C_(4)H_(8)S→C_(4)H9S^(*)→C_(4)H_(9)^(*)+SH^(*)→C_(4)H_(10)+H_(2)S.Butane and H_(2)S are produced in the reaction,corresponding to the experimental results.This study provides a basis for understanding of the HDS mechanism of tetrahydrothiophene catalyzed by Ni_(2)P.

Enrichment characteristic of carbon atoms in solid-liquid zone of high carbon steel under different directional solidification rates

To reveal the formation mechanism and main influencing factors of C-segregation in high carbon steel under different solidification rates(40,80,160,200 and 320μm·s^(-1)),the enrichment characteristics of carbon atoms in the solid-liquid zone of Fe-0.61%C steel were studied using a zone melting liquid metal cooling apparatus and electron probe microanalysis.The relationships among micro-segregation of carbon atoms,solid-liquid interface morphology and solidification rate were fully discussed.The results show that large dendrite spacing and a slow-moving dendritic interface create less resistance and more time for the migration of interdendritic carbon atoms to liquid zone.This results in the continuous enrichment of carbon atoms in liquid zone,further expands the solid-liquid temperature range,prolongs the solidification time of molten steel,and causes the formation of carbon micro-segregation at the solidification end as the solidification rate is 40μm·s^(-1).Conversely,abundant and elongated secondary dendrite arms with small spacing seriously impede the diffusion of interdendritic carbon-rich molten steel to liquid zone.As a result,there is only obvious dendrite segregation,but little difference in the carbon content along the solidification direction as solidification rate exceeds 200μm·s^(-1).

Analgesic, anti-inflammatory and antioxidant effects of ultrasound-guided lower extremity nerve block for elderly hip arthroplasty

Objective:To study the analgesic, anti-inflammatory and antioxidant effects of ultrasound-guided lower extremity nerve block for elderly hip arthroplasty.Methods: A total of 99 elderly patients with femoral neck fractures who underwent hip arthroplasty in our hospital between January 2017 and March 2018 were selected, and the anesthetic solutions were reviewed and used to divide the enrolled patients into the control group (n=51) who accepted conventional general anesthesia and the nerve block group (n=48) who accepted ultrasound-guided lower extremity nerve block anesthesia. The differences in the serum levels of pain mediators, inflammatory mediators and oxidative stress indexes were compared between the two groups immediately after surgery (T0), 12 h after surgery (T1) and 24 h after surgery (T2).Results: At T0, serum levels of pain mediators, inflammatory mediators and oxidative stress indexes were not significantly different between the two groups. At T1 and T2, serum pain mediators PGF2a, SP and NPY levels of nerve block group were lower than those of control group;serum inflammatory mediators IL-1β, TNF-α and hs-CRP levels were lower than those of control group;serum oxidative stress indexes T-AOC and SOD levels were higher than those of control group whereas MDA and LHP levels were lower than those of control group.Conclusion:Ultrasound-guided lower limb nerve block for elderly hip arthroplasty has exact analgesic, anti-inflammatory and antioxidant effects.

深层砂岩储层成岩作用差异性及与储层质量的关系——以准噶尔盆地中部征沙村地区侏罗系为例

为认识深层碎屑岩储层质量的控制因素及有效储层分布规律,以准噶尔盆地中部征沙村地区下侏罗统三工河组砂岩储层为例,利用岩心样品的铸体薄片、扫描电镜、碳氧同位素、X?射线衍射及常规物性测试手段,研究了储层岩石学和成岩作用特征,讨论了成岩作用对不同类型储集岩石相的影响,并建立了岩石相—沉积微相的联系。结果表明:研究区三工河组砂岩成分成熟度低,主要为长石岩屑砂岩,自生矿物包括碳酸盐、自生黏土、硬石膏及硅质等;总体为低—特低孔渗性储层,非均质性强。依据岩石学组构和成岩作用差异,可将储集砂岩主要划分为极细—细粒富塑性颗粒砂岩、方解石胶结砂岩和中—细粒贫塑性颗粒砂岩。不同岩石相经历了差异性成岩作用:其中富塑性颗粒砂岩表现为强压实、弱胶结和弱溶蚀特征;方解石胶结砂岩则表现为强胶结、弱压实和弱溶蚀特征,二者均在成岩阶段早期致密化;贫塑性颗粒砂岩表现为中等压实、弱—中等胶结、强溶蚀。成岩阶段早期压实作用和胶结作用程度低,不但能保留原生孔隙,亦能遭受后期深埋阶段的酸性流体改造,形成深层物性较好的有效储集岩。不同岩石相的分布总体受沉积微相控制,物性最佳的贫塑性颗粒砂岩主要分布在分流河道中下部或河口坝中上部,这种分布模式将为寻找深层有效储层提供指导。

Impact of obstructive sleep apnea on pulmonary hypertension in patients with chronic obstructive pulmonary disease

Background:Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) syndrome are highly prevalent respiratory conditions. Their coexistence is referred to as the overlap syndrome. They are both related to pulmonary hypertension (PH) development. This study investigated the effects of OSA on PH in patients with COPD and the associated factors. Methods: Consecutive patients with stable COPD were recruited for an observational cross-sectional study from September 2016 to May 2018 at Peking University Third Hospital. In total, 106 patients with COPD were enrolled and performed home portable monitoring and echocardiography. OSA was defined by an apnea hypopnea index (AHI)>10 events/h. Based on OSA absence or presence, patients were divided into the COPD with OSA and COPD without OSA groups. Factors affecting pulmonary artery pressure (PAP) and PH were identified using univariate analysis and logistic regression models. Results: In the 106 patients with COPD, the mean age was 69.52 years, 91.5% were men, and the mean forced expiratory volume in 1 s (FEV!) percentage of predicted was 56.15%. Fifty-six (52.8%) patients with COPD were diagnosed with OSA, and 24 (22.6%) patients with COPD were diagnosed as PH. Compared with COPD without OSA group, the median PAP in COPD with severe OSA group increased by 5 mmHg (36.00 [26.00-50.00] mmHg vs. 31.00 [24.00-34.00] mmHg, P = 0.036). COPD with percent of night-time spent with oxygen saturation below 90%(T90)> 10% group had higher PAP than COPD with T90 < 1 % group (36.00 [29.00-50.00)] mmHg vs. 29.00 [25.50-34.00] mmHg, F = 7.889, P = 0.007). Univariate analysis revealed age, FEVi% predicted, T90, and Charlson index had statistically significant effects on PH. Multiple regression analysis showed a significant and independent effect of both FEVj% predicted (odds ratio [OR]= 3.46;95% confidence interval [Cl]: 1.15-10.46;P = 0.028) and AHI (OR = 3.20;95% Cl: 1.09-19.35;P = 0.034) on PH. Conclusions: Patients with COPD with OSA are more susceptible to PH, which is associated with declining lung function and increased severity of OSA. Thus, nocturnal hypoxemia and OSA in elderly patients with COPD should be identified and treated.

ntranasal Endoscopic Prelacrimal Recess Approach to Sinonasal Juvenile Ossifying Fibroma

To the Editor： Ossifying fibroma is a benign but rare fibro-osseous tumor in the eraniofacial region. Complete resection is the only way to treat it. Here, we reported one case of maxillary juvenile ossifying fibroma operated with intranasal endoscopic prelacrimal recess approach in which nasolacrimal duct （NLD） and inferior turbinate （IT） were spared.

Fast and Error-Bounded Space-Variant Bilateral Filtering

The traditional space-invariant isotropic kernel utilized by a bilateral filter(BF)frequently leads to blurry edges and gradient reversal artifacts due to tlie existence of a large amount of outliers in the local averaging window.However,the efficient and accurate cstiinatioii of space-variant k(4rnels which adapt to image structures,and the fast realization of the corresponding space-variant bilateral filtering are challenging problems.To address these problems,we present a space-variant BF(SVBF).and its linear time and error-bounded acceleration method.First,we accurately estimate spacevariant,anisotropic kernels that vary with image structures in linear time through structure tensor and mininnini spanning tree.Second,we perform SVBF in linear time using two error-bounded approximation methods,namely,low-rank tensor approximation via higher-order singular value decomposition and exponential sum approximation.Tlierefore.the proposed SVBF can efficiently achieve good edge-preserving results.We validate the advantages of the proposed filter in applications including:image denoising,image enhancement,and image focus editing.Experimental results(leinonstrate that our fast and error-bounded SVBF is superior to state-of-the-art methods.