风力机涡流发生器斜向布局多目标优化

基于最优拉丁超立方试验设计法确定涡流发生器斜向布局参数和试验方案,耦合计算流体力学方法(CFD)和滑移网格技术计算风力机的推力和扭矩,并耦合反向传播(BP)神经网络与遗传算法,建立风力机涡流发生器斜向布局气动性能模型。通过5组测试算例,建立遗传算法优化BP神经网络的风力机涡流发生器斜向布局气动性能模型,气动性能模型预测值和模拟仿真值的误差与均方根均较小,表明气动模型的准确性较高。耦合多目标遗传算法,构建风力机涡流发生器斜向布局多目标优化方法,开展风力机涡流发生器优化。结果表明:相比原涡流发生器方案,优化后的涡流发生器诱导涡的最大涡量增大10.47%,风力机叶片截面流动分离得到有效抑制,风力机功率提升9.963%,而推力仅增大1.864%,风力机气动性能得到进一步提升。

Long-term operation optimization of circulating cooling water systems under fouling conditions

Fouling caused by excess metal ions in hard water can negatively impact the performance of the circulating cooling water system(CCWS)by depositing ions on the heat exchanger's surface.Currently,the operation optimization of CCWS often prioritizes short-term flow velocity optimization for minimizing power consumption,without considering fouling.However,low flow velocity promotes fouling.Therefore,it's crucial to balance fouling and energy/water conservation for optimal CCWS long-term operation.This study proposes a mixed-integer nonlinear programming(MINLP)model to achieve this goal.The model considers fouling in the pipeline,dynamic concentration cycle,and variable frequency drive to optimize the synergy between heat transfer,pressure drop,and fouling.By optimizing the concentration cycle of the CCWS,water conservation and fouling control can be achieved.The model can obtain the optimal operating parameters for different operation intervals,including the number of pumps,frequency,and valve local resistance coefficient.Sensitivity experiments on cycle and environmental temperature reveal that as the cycle increases,the marginal benefits of energy/water conservation decrease.In periods with minimal impact on fouling rate,energy/water conservation can be achieved by increasing the cycle while maintaining a low fouling rate.Overall,the proposed model has significant energy/water saving effects and can comprehensively optimize the CCWS through its incorporation of fouling and cycle optimization.

Least Squares Hermitian Problem of Matrix Equation (<i>AXB</i>, <i>CXD</i>) = (<i>E</i>, <i>F</i>) Associated with Indeterminate Admittance Matrices

For A&#8712;Cm&#935;n, if the sum of the elements in each row and the sum of the elements in each column are both equal to 0, then A is called an indeterminate admittance matrix. If A is an indeterminate admittance matrix and a Hermitian matrix, then A is called a Hermitian indeterminate admittance matrix. In this paper, we provide two methods to study the least squares Hermitian indeterminate admittance problem of complex matrix equation (AXB,CXD)=(E,F), and give the explicit expressions of least squares Hermitian indeterminate admittance solution with the least norm in each method. We mainly adopt the Moore-Penrose generalized inverse and Kronecker product in Method I and a matrix-vector product in Method II, respectively.

血糖信息化管理系统对2型糖尿病患者治疗效果及自我管理能力的影响分析

目的分析血糖信息化管理系统对糖尿病患者的疗效及自我管理能力的影响。方法实施全院血糖管理前,随机选取2016年1月-2016年6月在郑州人民医院治疗的112例2型糖尿病患者为对照组;实施全院血糖管理后,选取2016年7月-2016年12月该院收治的112例手术患者为观察组。对照组患者采用传统床旁血糖仪及血糖管理模式;观察组患者采用全信息化血糖管理模式。对比患者的自我管理能力的改变,检测患者空腹血糖(FPG)、餐后2 h血糖(2 h PG)、三酰甘油(TG)、总胆固醇(TC)及糖化血红蛋白(Hb A1c)等指标进行比较。结果观察组对血糖相关知识的知晓率、血糖达标率及糖化血红蛋白达标率高于对照组(P<0.05)。观察组的自测血糖率、适当运动率、合理饮食率及规范用药率均高于对照组(P<0.05)。观察组的FPG、2 h PG、TC、TG及Hb AIc低于对照组(P<0.05)。结论医院实施全院血糖信息化管理后,方便医护人员获取患者信息,纠正患者不良生活习惯,有效改善患者的血糖指标,提高患者对医院服务的满意度。

Adaptive signal control and coordination for urban traffic control in a connected vehicle environment: A review

Existing signal control systems for urban traffic are usually based on traffic flow data from fixed location detectors.Because of rapid advances in emerging vehicular communication,connected vehicle(CV)-based signal control demonstrates significant improvements over existing conventional signal control systems.Though various CV-based signal control systems have been investigated in the past decades,these approaches still have many issues and drawbacks to overcome.We summarize typical components and structures of these existing CV-based urban traffic signal control systems and digest several important issues from the summarized vital concepts.Last,future research directions are discussed with some suggestions.We hope this survey can facilitate the connected and automated vehicle and transportation research community to efficiently approach next-generation urban traffic signal control methods and systems.

Analysis on the Technical Standardization System of Juvenile Product in Europe and the United States of America and Strategies of Technical Measures of Trade

China is the largest country in the trade of juvenile products in the world. However, the products suffered the loss of technical barriers to trade from Europe and the United States of America increased year by year. This paper analyzes the standard system of juvenile products in Europe and the United States of America with the method of standard comparison, to find its relative technical advantages, explore the reasons for the recall notification of juvenile products exported to the above regions by China, propose strategies for breaking down the technical measures of trade, and promote the development of international juvenile product export trade.

Study on the Influence of Blade Outlet Backsweep Angle on Performance of Impeller

As an important parameter of compressor impeller, the design value of blade outlet backsweep angle has a great influence on the performance of impeller. In this paper, six impellers with blade outlet backsweep angle β2B equal to 0°, 10°, 20°, 30°, 40°, and 50° were designed to evaluate the influences of impeller backsweep angle β2B on the performance, characteristics of gas flow and equivalent stress using computational fluid dynamics (CFD) and finite element analysis (FEA). Results indicated that the performance curve for the outlet backsweep blade angle β2B of 50° has the largest stable operating range. The isentropic efficiency of the impeller with backsweep angle β2B equal to 40° is 16.8% - 25.9% higher than that of the impeller with backsweep angle β2B equal to 0°. When the blade outlet backsweep angle is 30°, the equivalent stress distribution of the impeller is more uniform, the maximum equivalent stress is the smallest.

应用内镜下贲门部套扎紧缩成形术治疗胃食管反流病的临床疗效

目的探究内镜下贲门部套扎紧缩成形术治疗胃食管反流病的临床疗效。方法选取2016年3月-2018年2月郑州颐和医院收治的胃食管反流病患者100例作为研究对象,分为射频组和套扎组,每组各50例患者。射频组患者行内镜下射频技术治疗,套扎组患者采用内镜下贲门部套扎紧缩成形术治疗。比较两组患者治疗效果、术前和术后6个月食管测压和反流情况以及并发症发生率。结果套扎组患者治疗效果(98.00%)明显优于射频组(76.00%),两组比较,差异有统计学意义(P<0.05);套扎组患者术后6和12个月24 h反流时间、反流次数和胃食管反流病自测量表(GERD-Q)评分明显低于术前,且套扎组低于射频组,差异均有统计学意义(P<0.05);套扎组术后6和12个月食管括约肌压力和食管残余压明显高于术前,且套扎组高于射频组,两组比较,差异均有统计学意义(P<0.05);套扎组术后并发症发生率(10.00%)也明显低于射频组(34.00%),两组比较,差异有统计学意义(P<0.05)。结论内镜下贲门部套扎紧缩成形术治疗胃食管反流病效果较好,可以缩短胃反流时间、减少反流次数、缓解症状、增加食管括约肌压力和食管残余压、减少并发症的发生率。

三维大孔/介孔碳-碳化钛复合材料用于无枝晶锂金属负极

金属锂具有超高的理论容量(3860 mAh·g^(−1))和低氧化还原电位(−3.04 V vs.标准氢电极),是极具吸引力的下一代高能量密度电池的负极材料。然而,循环过程中的体积膨胀、锂枝晶生长和“死锂”等问题严重的限制了其实际应用。合理设计三维骨架调控金属锂的成核行为是抑制锂枝晶生长的有效策略。本文中,我们发展了一种“软硬双模板”的方法合成了兼具大孔和介孔的三维碳-碳化钛(Three-dimensional macro-/mesoporous C-TiC,表示为3DMM-C-TiC)复合材料。多级孔道为金属锂的沉积提供了足够的空间,缓冲充放电中巨大的体积变化。此外,TiC的引入显著增强多孔骨架的导电性,改善锂金属的成核行为,促进金属锂的均匀成核和沉积,抑制锂枝晶生长。3DMM-C-TiC||Li电池测试表明,在循环300圈以后,库伦效率仍保持在98%以上。此外,所得材料与LiFePO_(4)(LFP)组成的全电池也表现出优异的倍率和循环性能。本工作为无枝晶锂金属负极的设计提供了新的思路。

Temperature distribution and dynamic control of secondary cooling in slab continuous casting

To predict and optimize the temperature distribution of slab continuous casting in steady operational state, a three-dimensional model （named ＂offline model＂） based on the heat transfer and solidification theories was developed. Both heat transfer and flux distribution characteristics of the nozzle sprays on the slab were considered, and the complicated boundary conditions, such as spray cooling, natural convection, thermal radiation as well as contact cooling of individual rolls were involved in the model. By using the calibrated caster dependent model factors, the calculated temperature and shell thickness accorded well with the measured. Furthermore, a dynamic secondary water cooling control system was also developed on the basis of a two-dimensional transient heat transfer model （named ＂online model＂） and incremental PID control algorithm to reduce slab surface temperature fluctuation in unsteady state. Compared with the traditional spray table control method, the present online model and dynamic PID control demonstrate a higher capability and flexibility to adjust cooling water flowrate and reduce slab surface temperature fluctuation when the casting speed is changed.

弱双四元数矩阵方程AXAH+BYBH=C的反Hermite解

在本文中,我们讨论弱双四元数矩阵方程AXAH+BYBH=C的反Hermite解,其中矩阵A,B是已知的弱双四元数矩阵,C是已知的弱双四元数反Hermite矩阵,X,Y是未知的弱双四元数反Hermite方阵。本文的目标是建立解存在的充分必要条件和通解表达式。

Pt-Co single atom alloy catalysts: Accelerated water dissociation and hydrogen evolution by strain regulation

The alkaline hydrogen evolution reaction(HER) on Pt-based catalysts is largely limited by the slow water dissociation kinetics. Pt-based single atom alloy catalysts(SAAC) with water dissociation sites have been demonstrated as excellent alkaline HER catalysts. However, the regulation of their activity and stability at the atomic scale is still a great challenge. Herein, the kinetic and stability issues are successfully resolved via engineering the electronic structure of Pt-Co SAAC by Au-induced tensile strain. The atomic dispersion of Co into the Pt shell was confirmed by extended X-ray absorption fine structure and the electronic structure and catalytic HER performance was modulated by the tensile strain induced by the Pt shell thickness. An inverse volcano-type relation between HER activity and surface strain was found.Density functional theory(DFT) calculations reveal that the Au-induced tensile strain on Pt-Co shell can not only boost the adsorption and dissociation kinetics of water at Co site by upshifting the dband and promoting the electron transfer, but also downshift the d-band center of Pt in Pt-Co shell, leading to optimized H* adsorption/desorption. The champion catalyst provides an overpotential of only 14 m V at the current density of 10 mA cm^(-2). This work not only provides an effective strategy for the construction of single-atom alloy electrocatalysts for high performance toward alkaline HER but also sheds light on the understanding of the reaction mechanism at the atomic level.

Idiopathic tenosynovitis of the wrist with multiple rice bodies: A case report and review of literature

BACKGROUND Multiple rice bodies in the wrist is a rare disorder that requires surgery,and there are still many uncertainties regarding its diagnosis and treatment.CASE SUMMARY We described a rare case of chronic idiopathic tenosynovitis with rice bodies of the wrist in a 71-year-old man and reviewed similar topics in the literature.A total of 43 articles and 61 cases were included in the literature review.Our case had a usual presentation:it was similar to those in the literature.The affected population was mainly older adults,with an average age of 59.43(range,3 to 90)years.The male-to-female ratio was 1.54:1(37/24).Most of them showed limited swelling and pain,only 23.0%had carpal tunnel symptoms,and the average disease duration was 18.03(0.5-60)mo.Wrist flexor tendon sheath involvement was the most common(95.1%,58/61),and only 3 cases had extensor tendon sheath involvement.The main causes were tuberculosis(34.4%,21/61),nontuberculous mycobacteria(24.6%,15/61),idiopathic tenosynovitis(31.1%,19/61),and others(9.84%,6/61).There were 10 patients with recurrences;in 6 of them,were due to non-tuberculous mycobacterial infections.CONCLUSION We reported a case of wrist idiopathic tenosynovitis with rice body formation,and established a clinical management algorithm for wrist tenosynovitis with rice bodies,which can provide some reference for our clinical diagnosis and treatment.The symptoms of rice-body bursitis of the wrist are insidious,nonspecific,and difficult to identify.The aetiology is mainly idiopathic tenosynovitis and mycobacterial(tuberculosis or non-tuberculous)infections;the latter are difficult to treat and require long-duration systemic combination antibiotic therapies.Therefore,before a diagnosis of idiopathic tenosynovitis is made,we must exclude other causes,especially mycobacterial infections.

Hollow Nanocages of Ni_(x)Co_(1-x)Se for Efficient Zinc–Air Batteries and Overall Water Splitting

Developing Earth-abundant,highly efficient,and anticorrosion electrocatalysts to boost the oxygen evolution reaction(OER),oxygen reduction reaction(ORR),and hydrogen evolution reaction(HER) for the Zn–air battery(ZAB) and for overall water splitting is imperative.In this study,a novel process starting with Cu2O cubes was developed to fabricate hollow NixCo1-xSe nanocages as trifunctional electrocatalysts for the OER,ORR,and HER and a reasonable formation mechanism was proposed.The Ni0.2Co0.8Se nanocages exhibited higher OER activity than its counterparts with the low overpotential of 280 mV at 10 mA cm-2.It also outperformed the other samples in the HER test with a low overpotential of 73 mV at 10 mA cm-2.As an air–cathode of a self-assembled rechargeable ZAB,it exhibited good performance,such as an ultralong cycling lifetime of > 50 h,a high round-trip efficiency of 60.86%,and a high power density of 223.5 mW cm-2.For the application in self-made all-solid-state ZAB,it also demonstrated excellent performance with a power density of 41.03 mW cm-2 and an open-circuit voltage of 1.428 V.In addition,Ni0.2Co0.8Se nanocages had superior performance in a practical overall water splitting,in which only 1.592 V was needed to achieve a current density of 10 mA cm-2.These results show that hollow NixCo1-xSe nanocages with an optimized Ni-to-Co ratio are a promising cost-effective and high-efficiency electrocatalyst for ZABs and overall water splitting in alkaline solutions.

Anti-CRISPRs: The natural inhibitors for CRISPR-Cas systems

CRISPR (clustered regularly interspaced short palindromic repeats)‐Cas (CRISPR associated protein) systems serve as the adaptive immune system by which prokaryotes defend themselves against phages. It has also been developed into a series of powerful gene‐editing tools. As the natural inhibitors of CRISPR‐Cas systems, anti‐CRISPRs (Acrs) can be used as the “off‐switch” for CRISPR‐Cas systems to limit the off‐target effects caused by Cas9. Since the discovery of CRISPR‐Cas systems, much research has focused on the identification, mechanisms and applications of Acrs. In light of the rapid development and scientific significance of this field, this review summarizes the history and research status of Acrs, and considers future applications.

Characteristics of oil shale pyrolysis in a two-stage fluidized bed

Rapid pyrolysis of oil shale coupled with in-situ upgrading of pyrolysis volatiles over oil shale char was studied in a laboratory two-stage fluidized bed(TSFB) to clarify the shale oil yield and quality and their variations with operating conditions. Rapid pyrolysis of oil shale in fluidized bed(FB) obtained shale oil yield higher than the Fischer Assay oil yield at temperatures of 500-600 ℃. The highest yield was 12.7 wt% at 500 ℃ and was about1.3 times of the Fischer Assay oil yield. The heavy fraction(boiling point > 350 ℃) in shale oil at all temperatures from rapid pyrolysis was above 50%. Adding an upper FB of secondary cracking over oil shale char caused the loss of shale oil but improved its quality. Heavy fraction yield decreased significantly and almost disappeared at temperatures above 550 ℃, while the corresponding light fraction(boiling point < 350 ℃) yield dramatically increased. In terms of achieving high light fraction yield, the optimal pyrolysis and also secondary cracking temperatures in TSFB were 600 ℃, at which the shale oil yield decreased by 17.74% but its light fraction yield of 7.07 wt% increased by 86.11% in comparison with FB pyrolysis. The light fraction yield was higher than that of Fischer Assay at all cases in TSFB. Thus, a rapid pyrolysis of oil shale combined with volatile upgrading was important for producing high-quality shale oil with high yield as well.

Effect of Ramipril on Renin-Angiotensin-Aldosterone System of Young and Middle-Aged Patients with Hypertension

Objective:To explore the effect of Ramipril on renin-angiotensin-aldosterone system of young and middle-aged patients with hypertension.Methods 90 young and middle-aged patients with hypertension who had been seeking treatment in the hospital between August 2017 and August 2018 were selected and randomly divided into a control group and an observation group according to the random number table,with 45 cases in each group.The control group received Amlodipine for treatment,whereas the observation group was given Amlodipine combined with Ramipril for treatment.The hemodynamic indexes,blood lipid,blood pressure,angiotensinⅡ(AngⅡ),plasma renin(PRA),aldosterone(ALD)levels and incidence of adverse reactions during the medication in the two groups were compared before and after treatment.Results After treatment,thefibrinogen,plasma viscosity and whole blood viscosity in the observation group were significantly higher than those in the control group,with statistically significant difference between the two groups(P<0.05);total cholesterol(TC),triacylglycerol(TG)and low density lipoprotein cholesterin(LDL-C)in the observation group were significantly lower than those in the control group,and statistically significant difference was registered between the two groups(P<0.05);the diastolic pressure and systolic pressure in the observation group were decreased more significantly compared with the control group,with statistically significant difference shown between the two groups(P<0.05);the AngⅡ,ALD and PRA levels in the observation group were significantly lower than the control group,and the difference between two groups were statistically significant(P<0.05);during the medication,no significant bleeding or liver and kidney function damages occurred in the two groups.Conclusions For young and middle-aged patients with hypertension,the treatment with Ramipril,which is of high safety,can effectively improve the activity of their renin-angiotensin-aldosterone system,reduce the level of blood pressure and AngⅡ,ALD and PRA levels.

The levels of serum cystatin C, brain natriuretic peptide in traumatic patients and correlation analysis with traumatic severity

Objective:To observe the levels of serum cystatin C (Cys C), brain natriuretic peptide (BNP) in traumatic patients and correlation analysis with traumatic severity.Methods:120 emergency traumatic patients in emergency department of our hospital were rolled from December 2015 to December 2016, who were divided into minor trauma group (n=41), severe trauma group (n=43) and critical trauma group (n=36) according to the injury severity score (ISS). The levels of serum Cys C, BNP of the patients in the 3 groups were detected on 0 h, 24 h, 3 d and 7 d after admission respectively. Pearson correlation analysis of the levels of serum Cys C, BNP and ISS.Results: There were no significant differences in the levels of serum Cys C, BNP on 0 hours between the three groups;There were no significant differences in the levels of serum Cys C, BNP on 0 h, 24 h, 3 d and 7 d in minor trauma group;The levels of serum Cys C, BNP on 24 h, 3 d and 7 d were all higher than those of 0 h in severe trauma group, and the levels of serum Cys C on 3 d and 7 d were both higher than those of 24 h;The levels of serum Cys C, BNP on 24 h, 3 d and 7 d were all higher than those of 0 h in critical trauma group, the levels of serum Cys C, BNP on 3 d and 7 d were both higher than those of 24 h, and the levels of serum Cys C on 7 d were higher than those of 3 d;The levels of serum Cys C, BNP in severe trauma and critical trauma groups were significantly higher compared with minor trauma group on 24 h, 3 d and 7 d. Pearson correlation analysis, the level of serum Cys C were positively correlated with ISS, the level of serum BNP were positively correlated with ISS.Conclusion:Different levels of traumatic patients had different levels of serum Cys C, BNP increased at different times. Pearson correlation analysis showed that the levels of serum Cys C, BNP were both positively correlated with traumatic severity, which suggested that the levels of serum Cys C, BNP may be important indicators of traumatic severity and could provide important reference value for clinical evaluation of traumatic severity.

Impact of Mo/Ni alloying on microstructural modulation and low-temperature toughness of high-strength low-alloy steel

The high-strength low-alloy steel plates with varying Ni/Mo contents were manufactured using the thermos-mechanical control process.The investigation was conducted to explore the effect of Ni/Mo microalloying on microstructure evolution and mechanical properties of the steel.The results revealed that the increase in Ni content from 1 to 2 wt.%reduced the transition temperature of ferrite and the growth range of ferritic grain was narrowed,which promoted grain refinement.The optimized combination of grain size,high-angle grain boundaries(HAGBs),and martensite-austenite(M-A)islands parameter contributed to the excellent impact toughness of S1 steel at-100℃(impact absorbed energy of 218.2 J at-100℃).As the Mo increases from 0 to 2 wt.%,the matrix structure changes from multiphase structure to granular bainite,which increases the average effective grain size to~4.62 pm and reduces HAGBs proportion to~36.22%.With these changes,the low-temperature impact toughness of S3 steel is weakened.In addition,based on the analysis of the characteristics of crack propagation path,it was found that M-A islands with low content(~2.21%)and small size(~1.76 pm)significantly retarded crack propagation,and the fracture model of M-A islands with different morphologies was further proposed.Furthermore,correlation between behaviour of delamination and toughness was further analysed by observing delamination size and impact energy parameters.

生物活性含硒化合物的荧光成像分析

硒是一种生命系统内必需的微量元素,并且发挥着至关重要的生物功能.硒的生物功能主要由含硒化合物所承载,具有各种各样的生物功能,如抗氧化、抗炎及促甲状腺激素等功能.目前,绝大多数含硒化合物在不同生理和病理过程中所发挥的具体生物功能仍未明确.因此,探究含硒化合物在不同生理和病理过程中的生物功能受到了极大的关注.近年来,采用荧光探针对含硒化合物进行荧光成像分析的研究方法得到快速发展.本文对这一研究领域的进展进行了概述,根据含硒化合物的种类分为4个部分:(1)硒代半胱氨酸的荧光分析;(2)硒化氢的荧光分析;(3)硫氧还蛋白氧化还原酶的荧光分析;(4)亚硒酸的荧光分析.最后对该领域未来的发展进行了展望.