关于具有二次相关性收获率的捕食与被捕食系统极限环的存在性分析

讨论了一类两种群具有二次相关性收获率的捕食与被捕食系统,利用常微分定性方法和分支理论,得到了系统平衡点处的性态和极限环的存在性条件,并用Matlab软件对其进行数值模拟,推广了相关文献中两种群捕食模型定性分析的相应结论.     

Duplex dual-labeled fluorescence probe-based melting curve and endpoint genotyping assays for genotyping of rs2000999 and haptoglobin gene deletion

Haptoglobin (Hp) is a hemoglobin-binding serum glycoprotein. Some variations in the Hp gene (HP) or Hp-related gene (HPR), including a single-nucleotide polymorphism in intron 2 of HRP, rs2000999, and a complete deletion of the HP gene (HP^del), one of the rare variants of HP, have been reported to correlate with the serum cholesterol concentration as well as the serum Hp concentration. In this study, we developed a duplex dual-labeled fluorescence probe-based method to simultaneously determine the rs2000999 G > A polymorphism by melting curve genotyping and the zygosity of HP^del by endpoint genotyping. This method was then validated by using the genomic DNA from 94 Japanese subjects for whom genotypes of rs2000999 and HP^del zygosity had already been determined. The results obtained with this method were in perfect agreement with the previous ones. Thus, the present method enables us to estimate these two polymorphisms in relatively large-scale groups of subjects, especially in Asian populations where the HP^del is distributed.     

CT检查参数对腰椎管狭窄症的诊断价值及与疗效、腰椎功能改善的相关性分析

选取我院60例腰椎管狭窄症(LSS)患者作为研究组,同期健康者60例作为对照组,探究CT检查参数对LSS的诊断价值及与疗效、腰椎功能改善的相关性。结果显示,研究组椎管面积、硬膜囊面积、椎管矢径、椎管横径、侧隐窝矢径、侧隐窝角小于对照组(P<0.05);CT各参数联合诊断LSS的AUC值大于任一参数单独诊断;疗效优良患者术后3个月椎管面积、硬膜囊面积、椎管矢径、侧隐窝矢径、侧隐窝角大于治疗前及非优良患者(P<0.05);经偏相关性分析发现,CT检查参数与疗效显著相关(P<0.05)。说明LSS疗效、腰椎功能改善情况与椎管面积、硬膜囊面积、椎管矢径等关系密切,CT检查对指导临床完善手术方案有重要意义。     

基于曲线问题情境的信息化教学尝试*——以“沉淀溶解平衡”为例

基于高中生对实验曲线理解困难的现状,为挖掘实验曲线的教学价值,以沉淀溶解平衡为例,结合课堂演示实验和教学软件,设计了“宏观微观符号曲线”多重表征教学为一体的实验探究课。根据沉淀溶解平衡实验证据,绘制实验曲线,构建微观模型和图像,从而培养学生的证据收集与应用意识,提高学生对曲线的分析和理解能力,领会各种变化曲线的来源。在曲线理解的基础上建立“溶解平衡转化”思维模型,以此为开展“曲线融入式”的问题引导型实验教学提供参考案例。     

用硝酸银溶液沉淀及分步沉淀卤素离子的数字化实验研究*

卤化银难溶电解质的沉淀溶解平衡是中学化学教学的重要知识点。应用本项目组研制的MXLab21先进数字化实验系统,结合银硫离子电极,测定AgNO₃溶液沉淀Cl^-,Br^-,I^-及其混合离子的沉淀曲线,即电动势(E)随AgNO₃溶液体积(V)变化的关系曲线。3种单一离子的沉淀曲线可以直观体现出滴定的电动势突跃范围与相应沉淀的溶度积大小的关系及其规律性变化。通过混合离子的沉淀曲线分析3种离子两两混合或3者混合时分步沉淀的可行性。Cl^-,Br^-,I^-的沉淀及分步沉淀的动态E-V曲线的建立,对中学化学教学具有重要作用,对化学学科核心素养的发展和培养具有重要价值。     

DOUBLESLICING: a non-iterative single profile multi-exponential curve resolution procedure. Application to time-domain NMR transverse relaxation data

A new non-iterative curve resolution technique for resolving single decay profiles is proposed. The new technique, called DoubleSlicing, is based on the Decra (Direct Exponential Curve Resolution Algorithm) principle. While the original Decra was designed to resolve several decay curves simultaneously and thus fitting common pure exponentials, DoubleSlicing can resolve single decay profiles by a simple double data transformation followed by an analytical and unique three-way decomposition. The new approach is successfully demonstrated on experimental NMR CPMG relaxation data, measured on combinations of unmixed paramagnetic CuSO(4) solutions. Decay signals of the water component were acquired following an innovative experimental design that ensured no interaction between the components present in each sample under observation. DoubleSlicing proved to be accurate in estimating relaxation times differing in one order of magnitude (range: 19.6-159.4ms). Its performance was comparable to discrete exponential fitting with the advantage of being much faster - in terms of computation time, DoubleSlicing outperformed exponential fitting by a factor of four.     

植物油中脂肪酸不同定量方法的比较分析

比较峰面积归一化法与标准曲线法两种方法分析植物油中脂肪酸百分比含量的差异。利用气相色谱-质谱联用仪(GC-MS)检测10种市售食用植物油中的8种主要脂肪酸,峰面积归一化法和标准曲线法计算脂肪酸的百分比含量。结果表明,标准曲线法与峰面积归一化法相比,肉豆蔻酸、棕榈酸、十七烷酸、硬脂酸和棕榈油酸所占的百分比升高,而油酸、亚油酸和亚麻酸比例降低;饱和脂肪酸比例升高,不饱和脂肪酸百分比降低。利用峰面积归一化法计算植物油中脂肪酸百分比时,降低了饱和脂肪酸比例,升高了不饱和脂肪酸比例,可能对健康有潜在的不利影响。建议使用标准曲线法计算不同植物油中脂肪酸的百分比。     

基于NI-DAQ的高采样实时数据绘制方法与实现

飞行试验实时监控中,对高采样数据通常采用曲线绘制进行分析与故障判断,这对数据绘制的实时性、精确性以及曲线长度等都提出了较高的要求。本文对基于NI-DAQ的曲线绘制方法进行了研究和软件设计,实现了客户端的高采样数据实时绘制与打印输出。结果证明,采用该方法绘制的参数曲线可以满足实时监控要求。     

光生物节律因子计算模型的研究

通过实验测量额头温度拟合光生物节律因子-额温差曲线,对现有评价光生物效应作用大小的BioEq模型和CLA模型的计算结果进行分析比较.利用不同图片LCD屏幕的光谱计算节律因子,发现两种模型对于绿色波段的光抑制较强,而对红色波段的光则与实际不相符.通过对九种不同颜色的LED光源测试额头温度,比较模型计算结果与实际光生物效应的作用,发现光生物节律因子与生理体征变化线性递增,其中对BioEq模型的直线拟合相关度达到0.95.     

Sulfur removal from bauxite water slurry (BWS) electrolysis intensified by ultrasonic

Effects of ultrasonic on desulfurization ratio from bauxite water slurry (BWS) electrolysis in NaOH solution were examined under constant current. The results indicated that ultrasonic improved the desulfurization ratio at high temperatures because of the diffusion and transfer of oxygen gas in electrolyte. However, due to the increase in oxygen gas emission, ultrasonic could not improve the desulfurization ratio obviously at low temperatures. Additionally, the particle size of bauxite became fine in the presence of ultrasonic, indicating that the mass transfer of FeS₂ phase was improved. According to the polarization curves, the current density increased in the presence of ultrasonic, indicating that the mass transfer of liquid phase was improved. The apparent activation energy (AAE) of electrode reaction revealed that ultrasonic did not change the pathway of water electrolysis. However, ultrasonic changed the pathway of BWS electrolysis, converting indirect oxidation into direct oxidation. The AAE of BWS electrolysis in the presence of ultrasonic was higher than that in the absence of ultrasonic. And the low AAEs (less than 20 kJ/mol) clearly indicated the diffusion control during BWS electrolysis reaction.