FRP约束混凝土力学性能影响因素分析

FRP作为一种新型人工复合材料,因其强度高、密度小、施工简便、耐腐蚀性高、不增加构件截面尺寸等优点,被广泛应用于土木工程结构加固中.FRP约束混凝土本构关系、极限抗压强度、极限应变等力学参数是进行结构强度补强和延性加固的前提和基础.为使FRP约束混凝土更好地应用于工程实践,基于有限元分析手段和国内外近10年来关于FRP约束混凝土的试验研究与分析成果,深入分析和研究了约束比、混凝土柱截面形状、尺寸、强度、FRP用量、模量、FRP强度以及延伸率对FRP约束混凝土力学性能的影响.     

条形码在包装上使用影响因素分析

条形码技术是数据自动识别十分有效的方法,条形码的使用效果与条形码制选择、包装位置和识读器类型等因素有密切关系,在此分析了影响条形码在包装上使用的因素以及采取相应的措施。     

影响膨化硝铵炸药性能的因素分析

文章从原材料和工艺条件等方面探讨了影响膨化硝铵炸药性能的几个因素,由此得出了膨化硝铵炸药的较佳工艺条件.     

配制参数对碱矿渣混凝土强度影响的研究

研究了配制参数碱组分种类和掺量、矿渣细度、溶矿比、矿渣/集料比和砂率等对碱矿渣混凝土强度的影响.研究表明,其它条件相同时,碱矿渣混凝土强度随矿渣细度增加而提高;随溶矿比的增大而降低;随矿组分用量增加而提高;矿渣/集料比和砂率对碱矿渣混凝土强度影响较小;模数在1.0～2.0范围内,碱矿渣混凝土的强度随水玻璃模数提高呈增长趋势.     

毫秒雷管延期元件秒量精度影响因素的研究

毫秒雷管延期元件的秒量精度影响因素很多,包括延期药质量、延期元件加工工艺、延期元件贮存等.通过对延期元件加工工艺中的不同拉拔结构、不同药芯直径和延期元件切长对毫秒雷管秒量影响的实验研究,找出提高延期元件秒量精度的工艺技术途径,为更好地生产该产品奠定基础.     

Instability during high strain rate compression of 2024 T351 aluminium

The flow behaviour of 2024 aluminium during drop weight compression tests was investigated. Use of cylindrical specimens of different height to diameter ratios, of different orientations and having undergone varying levels of prestrain, enabled the development of shear bands occuring within these specimens to be studied. The shear surfaces display a conical geometry and appear to develop in the presence of thermal softening after a flow stress maximum has been reached. Fracture along these surfaces appears to be associated with the rotation of strings of inclusions into the plane of the surface as well as severe deformation along the bands which leads to both thermal softening and exhaustion of matrix material ductility.     

Low Serum Parathyroid Hormone Is a Predictor of Early Death after Hip Arthroplasty in Hemodialysis Patients

Background and Purpose:  Colloid osmotic pressure (COP) in plasma rises by ultrafiltration during hemodialysis, and it consequently causes plasma refilling in which water moves from interstitial tissue to capillary space. Although hemodynamic stability is one of the important factors for good dialysis outcome, no informative and convenient indicators are available other than monitoring of blood pressure. Thus, we measured COP during hemodialysis whether COP can be used as an indicator for the hemodynamic status in comparison with hematocrit (Ht). Plasma osmolality, ultrafiltration volume, and the alteration of blood pressure were also measured to examine whether COP is associated with them.
Method:  Sixteen patients hospitalized in this hospital were examined. Amongst them, 10 patients underwent both dialysis and ultrafiltration, while 4 patients received only dialysis and 2 patients were with ultrafiltration only by extracorporeal ultrafiltration method. Ultrafiltration was performed with constant speed to the dry weight for 4 h. The measurements of COP, plasma osmolality, Ht levels, and blood pressure were performed at 30 min (12.5% of the total water removal), 1 h (25%), 2 h (50%), and 3 h (75%) after the start of hemodialysis and also at the end of dialysis (100%).
Result:  COP markedly rose by 26.0% (±13.3%) in the patients who received both dialysis and ultrafiltration, whereas Ht rose by only 13.6% (±5.21%). And the curve for COP increase was sigmoid shape, whereas that for Ht showed linear change. On the other hand, in the patients whose Ht levels showed low values, the curves for both COP and Ht showed similar pattern.
Conclusion:  These results suggest that COP is a more sensitive indicator to be monitored for the hemodynamic status than Ht during hemodialysis.     

关于结球白菜在真空预冷实验中温度分布影响因素的探讨

以天津产结球白菜作为实验对象,探讨复压阶段的温度回升,以及在真空室内不同摆放形式和不同包装方式对蔬菜最终温度分布的影响,对比分析试验数据,为今后真空预冷技术的推广应用提供参考.     

制造企业库存长鞭效应影响因子分析及控制方法

长鞭效应是供应链管理中由于供应链合作伙伴之间缺乏合作与协调的结果。从理论上刻画了长鞭效应的内在本质,分析了产生长鞭效应的原因,以一个跨国公司的库存管理为例,详细分析了影响长鞭效应三个方面的因子：（1）集中式与分散式管理;（2）需求与供应特征;（3）产品类型与库存再订货点。还从供需合作关系的角度提出了改善长鞭效应的几个控制方法。     

Is There Any Relationship between Serum Levels of IL‐10 and Atherosclerosis in Hemodialysis Patients?

Background:  Cardiovascular complications due to atherosclerosis (AS) are the major cause of mortality in hemodialysis (HD) patients. Inflammation may play an important role in the development of AS. Several studies have demonstrated the association of acute-phase proteins and cytokines with AS in the general population and in HD patients. Interleukin-10 (IL-10) is an anti-inflammatory cytokine. The aim of study was to compare serum levels inflammatory and anti-inflammatory indicators in HD patients according to the presence or absence of AS.
Methods:  Thirty-three HD patients were enrolled. AS was defined as the detection of plaques by Doppler ultrasonography. The patients were subgrouped according to the presence or absence of plaques. Serum levels of IL-1, IL-2, IL-6, IL-10, C-reactive protein (CRP) and tumor necrosis factor-α (TNF-α) were measured. The factors for AS such as age, gender, hypertension, hyperlipidemia, and HD duration were also evaluated.
Results:  We found that the patients with AS had significantly higher hs-CRP and lower IL-10. Blood pressure values were also increased in patients with AS. Additionally, there was an increased correlation between CRP and IL-10.
Conclusions:  AS(+) patients undergoing HD had low serum levels of anti-inflammatory cytokine IL-10 and high serum levels of hs-CRP. These results may suggest that the limitation of anti-inflammatory response in atherosclerotic uremic patients is a triggering or contributing factor for AS.     

Instability of biological nitrogen removal in a cokes wastewater treatment facility during summer

Failure in nitrogen removal of cokes wastewater occurs occasionally during summer season (38 degrees C) due to the instability of nitrification process. The objective of this study was to examine why the nitrification process is unstable especially in summer. Various parameters such as pH, temperature, nutrients and pollutants were examined in batch experiments using activated sludge and wastewater obtained from a full-scale cokes wastewater treatment facility. Batch experiments showed that nitrification rate of the activated sludge was faster in summer (38 degrees C) than in spring or autumn (29 degrees C) and the toxic effects of cyanide, phenol and thiocyanate on nitrification were reduced with increasing temperature. Meanwhile, experiment using continuous reactor showed that the reduction rate in nitrification efficiency was higher at 38 degrees C than at 29 degrees C. In conclusion, the instability of full-scale nitrification process in summer might be mainly due to washing out of nitrifiers by fast growth of competitive microorganisms at higher temperature under increased concentrations of phenol and thiocyanate.     

Experience with the Gambro Phoenix Hemodialysis Machine using Diascan and Exalis in a Pediatric Hemodialysis Unit

Introduction: In 2001 our Renal Dialysis Unit underwent a major renovation to five stations. The new space and funding allowed for acquisition of new state‐of‐the‐art hemodialysis machines. We describe our experience with the Gambro Phoenix with Diascan and Exalis. Prior to the move an evaluation was undertaken. Criteria for selection with a scoring tool were utilized to rate machine performance for use in children. The decision for the Gambro Phoenix machine was based on: the performance rated highly due to ease of set up; large viewing touch screen; compatibility with existing equipment; benefits of online clearance monitoring (Diascan); network data management system (Exalis) and the future availability of blood volume monitoring (Hemoscan). Our program was the first center to dialyze a pediatric patient on the Phoenix machine in Canada. Patients and results: 13 patients (age 2–23 years) were hemodialyzed between May 2002 and September 2003 for periods of 2 week to 16 months, greater than 5000 h of dialysis time. The move was not uneventful. During the first months of operation issues such as inadequate electrical supply for the new machines, reverse osmosis (RO) pump failure, leaks, and no emergency power to the RO were prevalent. The new software also exposed glitches. Subsequent Phoenix use proceeded uneventfully. Staff were able to problem solve easily with clinical and technical support from Gambro Canada. Education for the online clearance monitoring, Diascan and Exalis, was necessary. No major problems with dialysis were encountered. The benefits and reliability of Diascan have been previously described (Lindsay RM, Sternby J, Semin Dial. 2001; 14:300). Diascan readings provided real‐time measurement of sodium (Na), which correlated well with laboratory values. Automatic readouts of Kt/V allowed for monitoring of dialysis adequacy which was consistent with calculated percent reduction in urea (PRU). At this point, use of the Phoenix has been demonstrated to work well in a pediatric facility.     

Anti-Gravitational Instability of the Neutral Helium Film

The properties of the neutral helium (hydrogen) film under antigravitational conditions are described. The existence of the critical liquid film thickkness d_* is predicted. Some details of the liquid film profile reconstruction are discussed.     

Stock Volatility Increases the Mortality Risk of Major Adverse Cardiovascular Events and Suicide:A Case-Crossover Study of 12 Million Deaths

Stock volatility constitutes an adverse psychological stressor,but few large-scale studies have focused on its impact on major adverse cardiovascular events(MACEs)and suicide.Here,we conducted an individual-level time-stratified case-crossover study to explore the association of daily stock volatility(daily returns and intra-daily oscillations for three kinds of stock indices)with MACEs and suicide among more than 12 million individual decedents from all counties in the mainland of China between 2013 and 2019.For daily stock returns,both stock increases and decreases were associated with increased mortal-ity risks of all MACEs and suicide.There were consistent and positive associations between intra-daily stock oscillations and mortality due to MACEs and suicide.The excess mortality risks occurred at the cur-rent day(lag 0 d),persisted for two days,and were greatest for suicide and hemorrhagic stroke.Taking the present-day Shanghai and Shenzhen 300 Index as an example,a 1％decrease in daily returns was associated with 0.74％-1.04％and 1.77％increases in mortality risks of MACEs and suicide,respectively;the corresponding risk increments were 0.57％-0.85％and 0.92％for a 1％increase in daily returns and 0.67％-0.77％and 1.09％for a 1％increase in intra-daily stock oscillations.The excess risks were more pro-nounced among individuals aged 65-74 years,males,and those with lower education levels.Our findings revealed considerable health risks linked to sociopsychological stressors,which are helpful for the gov-ernment and general public to mitigate the immediate cardiovascular and mental health risks associated with stock market volatility.     

功能梯度材料制备过程影响因素的数值研究

本文用数值计算的方法对重力浇铸下Al—Si／SiC颗粒系统(合金基质的功能梯度材料)凝固过程进行了研究，分析了凝固条件及各种不同参数对铸件中颗粒和溶质浓度分布的影响。结果表明，凝固件中颗粒体积分数分布都大致可分为三个区域：靠近底部的颗粒堆积区，靠近顶部的颗粒体积分数减小或近似为零区，及中部附近颗粒体积分数近似保持不变区。浇铸的初始温度，颗粒初始体积分数，颗粒直径和冷却速率等参数对颗粒和溶质浓度分布有很大影响。     

Augmenting a Factorial Experiment When One Factor Is an Uncontrollable Random Variable: A Case Study

Process engineers at an automobile assembly plant wanted to develop a model for on-line process control in an assembly line. During an experiment to estimate the model, an uncontrollable variable was discovered to have a significant effect, but its values in the experiment were not representative of values in actual production. Through this case study, we present design criteria and assess sampling strategies for augmenting a factorial experiment to incorporate an additional factor that was found to be an uncontrollable independent normally distributed random variable. Our results demonstrate the potential improvement in on-line process control when experiments are augmented using these design criteria.     

Anisotropy Effect on the Flow-Induced Instability of the Solid-Superfluid Interface

At the solid-superfluid interface of ⁴ He a Kelvin–Helmholtz type instability is expected to occur with a tangential flow. Nonlinear effect in the instability is studied with a perturbation expansion. For an isotropic interface the amplitude of the destabilized crystallization wave grows without limit, which suggests a chaotic motion. With a strong crystal anisotropy and for the surface orientation of minimum stiffness, the amplitude has a stable fixed point and a corrugated interface may be stabilized. Increasing further the anisotropy changes the type of the bifurcation from subcritical to supercritical.     

Flow Instability of Molten GaAs in the Czochralski Configuration

The flow and heat transfer of molten GaAs under the interaction of buoyancy, Marangoni and crystal rotation in the Czochralski configuration are numerically studied by using a time-dependent and three-dimensional turbulent flow model for the first time. The transition from axisymmetric flow to non-axisymmetric flow and then returning to axisymmetric flow again with increasing centrifugal and coriolis forces by increasing the crystal rotation rate was numerically observed. The origin of the transition to non-axisymmetric flow has been proved to be baroclinic instability. Several important characteristics of baroclinic instability in the CZ GaAs melt have been predicted. These characteristics are found to be in agreement with experimental observations.