Microfluidic-based single cell trapping using a combination of stagnation point flow and physical barrier

Single cell trapping in vitro by microfluidic device is an emerging approach for the study of the relationship between single cells and their dynamic biochemical microenvironments. In this paper, a hydrodynamic-based microfluidic device for single cell trapping is designed using a combination of stagnation point flow and physical barrier.The microfluidic device overcomes the weakness of the traditional ones, which have been only based upon either stagnation point flows or physical barriers, and can conveniently load dynamic biochemical signals to the trapped cell. In addition, it can connect with a programmable syringe pump and a microscope to constitute an integrated experimental system.It is experimentally verified that the microfluidic system can trap single cells in vitro even under flow disturbance and conveniently load biochemical signals to the trapped cell. The designed micro-device would provide a simple yet effective experimental platform for further study of the interactions between single cells and their microenvironments.

Development Barriers and Cut-in Points of Next Generation Services

The paper discusses the characteristics of next generation services, and analyzes its development barriers and cut-in points.Broadband services that NGN offers have to transit from an unknown state to an popular state to become a scale economy.Personal information and communication services and multimedia entertainment services will be the cut-in points.

Polynomial-time interior-point algorithm based on a local self-concordant finite barrier function

The choice of self-concordant functions is the key to efficient algorithms for linear and quadratic convex optimizations, which provide a method with polynomial-time iterations to solve linear and quadratic convex optimization problems. The parameters of a self-concordant barrier function can be used to compute the complexity bound of the proposed algorithm. In this paper, it is proved that the finite barrier function is a local self-concordant barrier function. By deriving the local values of parameters of this barrier function, the desired complexity bound of an interior-point algorithm based on this local self-concordant function for linear optimization problem is obtained. The bound matches the best known bound for small-update methods.

钆掺杂的高非线性和低漏流SnO_(2)基压敏电阻材料

本工作通过在SnO_(2)-Co_(3)O_(4)-Cr_(2)O_(3)-Ta_(2)O_(5)体系中引入Gd,制备了兼具高非线性系数和低泄漏电流的SnO_(2)压敏陶瓷材料。结果表明:Gd的掺杂能够促进晶粒生长,降低样品气孔率,并在掺杂量为0.25%(如无特殊说明均为摩尔分数)时获得了最佳的电气性能,非线性系数达到55,泄漏电流低至7.74 mA/cm^(2),同时电压梯度高达568 V/mm,在50 Hz频率下介电常数高达213,显示出其潜在的应用前景。但过饱和的掺杂会恶化压敏陶瓷的电气性能。本工作将非线性系数的变化归因于晶界势垒的提升,认为泄漏电流减小是晶界电阻升高,电子迁移率下降导致的,并从点缺陷的角度分析了晶界势垒升高的原因,系统地阐述了Gd的掺杂对SnO_(2)压敏电阻陶瓷电气性能和微观结构的影响机理。

基于海岸带生态功能评估的陆海连通生态廊道识别与优化研究

海岸带是陆海连接的重要区域,通常受到人类活动的影响最为突出,识别和优化陆海连通生态廊道,能够有效地保护和恢复生态系统连通性和完整性,对陆海生态流通、区域生态网络构建、开展关键生态节点保护修复也尤为重要。本研究基于“生态源地识别-阻力面构建-生态廊道提取-夹点、障碍点影响因素分析”的框架,以罗源湾海岸带为研究区,在海岸带生态功能评估基础上,结合Linkage Mapper模型和电路理论识别陆海连通区域生态廊道,并提取生态夹点、障碍点以及关键生态节点,分析节点区影响因素,提出廊道优化的建议。结果表明:①研究区共分布25条生态廊道,潜在14处生态夹点和生态障碍点,6处陆海连通关键节点;②生态廊道多分布于生态源地斑块连接处,生态夹点和障碍点多分布于廊道中生态阻力值较高的区域;③人类活动主导的驱动因子对关键生态节点的影响更多,自然因素为主的因子也有一定程度影响,但两者间的交互作用并不显著;④以“点-线-面”结合的廊道优化策略能够较好地实现海岸带陆海连接区域蓝绿生态网络格局构建。整体上,研究能够促进罗源湾海岸带生态源地斑块的连通性和完整性,保障陆海生态流通,提升海岸带区域生物多样性,维持海岸带生态系统健康和稳定状态。

副箱同步器锁止销热处理软点原因探究

主要针对副箱同步器锁止销渗碳淬火后存在的局部软点和表面硬度不合格问题,进行原因排查及探究。结果表明:软点是由于热处理渗碳层深局部不合格导致的,而渗碳层深局部不合格的原因是热处理前存在切削液、清洗液等残留物,因工艺设备特殊性,导致渗碳过程中阻渗。针对此原因进行了工艺优化改进,从而解决了软点问题。

Effective Diffusion Energy Barriers with the Boltzmann Distribution Assumption

We derived revised effective diffusion energy barriers following the Boltzmann distribution assumption for impurity atoms in a bulk material under the impact of various kinds of point defects to reveal the insights of migration mechanisms. The effective diffusion energy barriers of copper impurities in bulk zirconium were calculated through the first principle method under the presented hypothesis. Our results(?E_(||) =1.27 eV, ?E_⊥=1.31 eV) agreed well with the experimental results(?E_(||) =1.54 eV, ?E_⊥=1.60 eV), which validated bulk diffusion as the major mechanism for copper diffusion in zirconium. The effective diffusion energy barriers could be used for estimating whether the defects will accelerate the diffusion or slow them down by acting as traps of the impurity atoms. On the other hand, the first principle results of the impurity diffusion via defects could be further used as inputs of larger scale computational simulations, such as MC(Monte Carlo) or Phase Field calculations.

Interfacial toughness evaluation of thermal barrier coatings by bending test

Determining the interfacial properties of thermal barrier coatings(TBCs) is imperative for their durability evaluation and further improvements. A ceramic coating(topcoat) and a NiCoCrALY bondcoat were atmospheric-plasma-sprayed(APS) on a stainless steel substrate. A modified three-point bending test was adopted to initiate and propagate the topcoat/bondcoat(TC/BC)interfacial crack. After a complete delamination, the fracture surfaces were examined by an optical microscope, which shows that the cracking plane was merely on the TC/BC interface. Based on the experimental results of load–displacement and crack length–displacement,the strain energy release rate G for crack propagation was calculated, and the averaged magnitude was 77.1 J/m^2.Repeatable results have indicated that the method can be used for the evaluation of interfacial fracture toughness in thermal barrier coatings and other multi-layer structures.

Penalized interior point approach for constrained nonlinear programming

A penalized interior point approach for constrained nonlinear programming is examined in this work. To overcome the difficulty of initialization for the interior point method, a problem equivalent to the primal problem via incorporating an auxiliary variable is constructed. A combined approach of logarithm barrier and quadratic penalty function is proposed to solve the problem. Based on Newton＇s method, the global convergence of interior point and line search algorithm is proven. Only a finite number of iterations is required to reach an approximate optimal solution. Numerical tests are given to show the effectiveness of the method.

Energetics and diffusion of point defects in Au/Ag metals:A molecular dynamics study

To reveal the potential aging mechanism for self-irradiation in Pu-Ga alloy,we choose Au-Ag alloy as its substitutional material in terms of its mass density and lattice structure.As a first step for understanding the microscopic behavior of point defects in Au-Ag alloy,we perform a molecular dynamics(MD)simulation on energetics and diffusion of point defects in Au and Ag metal.Our results indicate that the octahedral self-interstitial atom(SIA)is more stable than the tetrahedral SIA.The stability sequence of point defects for He atom in Au/Ag is:substitutional site>octahedral interstitial site>tetrahedral interstitial site.The He-V cluster(Hen Vm,V denotes vacancy)is the most stable at n=m.For the mono-vacancy diffusion,the MD calculation shows that the first nearest neighbour(1 NN)site is the most favorable site on the basis of the nudged elastic band(NEB)calculation,which is in agreement with previous experimental data.There are two peaks for the second nearest neighbour(2 NN)and the third nearest neighbour(3 NN)diffusion curve in octahedral interstitial site for He atom,indicating that the 2 NN and 3 NN diffusion for octahedral SIA would undergo an intermediate defect structure similar to the 1 NN site.The 3 NN diffusion for the tetrahedral SIA and He atom would undergo an intermediate site in analogy to its initial structure.For diffusion of point defects,the vacancy,SIA,He atom and He-V cluster may have an analogous effect on the diffusion velocity in Ag.

基于“服务重要性-生态敏感性-生物多样性”的内蒙古生态网络识别及优化

识别生态空间质量,构建区域保护网络对于优化生境布局、提高生态环境承载力以及维持生态系统稳定性具有重要意义。以内蒙古为例,研究构建“服务重要性-生态敏感性-生物多样性”的保护网络识别框架,基于生态系统服务重要性与生态敏感性评价识别生态源地。在此基础上,耦合现有自然保护地体系,利用最小累积阻力模型识别重要生态廊道,构建内蒙古保护网络。通过分析生态廊道与基础设施的空间叠置关系,提取待优化的生态踏脚石与生态障碍点。结果表明:(1)内蒙古Ⅰ级生态源地面积3.80×10^(4) km^(2),占研究区总面积的3.21%,与生态保护红线重合度较高。(2)在自然保护地和Ⅰ级生态源地的基础上,识别潜在生态廊道共84条,总长度约为15910 km,结合生态源地、潜在廊道和鸟类迁徙廊道构建内蒙古保护网络。(3)识别5条鸟类迁徙廊道、10处踏脚石优质生境建设点和81处生态障碍修复点。研究结果为内蒙古生态保护修复工程中物种迁移和能量流动网络的管理建设提供数据支持和位置参考。

企业生产的动态控制和优化

本文探讨了生产经营过程中决策者非常关心的一个问题—如何制定合理的采购和生产策略。在边界分红策略下,本研究考虑控制企业的采购和生产,建立了一个马氏决策模型,目的是寻找使得考察期内期望贴现红利最大的生产策略及对应的最优值函数。本文探讨了两种情形:(1)仅市场需求量是随机变量的单变量情形;(2)任意生产周期的单位成本与前期的市场需求及售价具有相关关系且服从一个联合分布的多变量情形。在每种情形下,本文给出了最优生产策略满足的条件,以及考察期有限长条件下值函数满足的迭代关系式与考察期长无限制条件下的值函数满足的Bellman方程,并运用压缩映射原理证明时长无限制时的最优值函数是Bellman方程的唯一解。

基于障碍函数内点法的防御武器配系部署建模与智能优化

针对防空任务中我方多平台、多武器、多区域部署带来的防御武器配系难以建模和实时优化难的问题,在考虑敌我双方攻防武器对抗博弈的条件下,提出了一种基于障碍函数内点法的我方防御武器部署优化模型,并综合武器防御效能、防御成本、保卫目标的资产价值等指标对模型进行智能优化解算与分析.首先,建立我方部阵地、防御武器与保卫目标的参数化模型,并建立我方武器对于敌方武器拦截的概率函数与约束条件;然后,将防御武器优化部署问题转化为性能指标函数为凸函数的无约束优化问题;最后,引入障碍函数内点法对其进行快速求解,给出了防御阵地武器部署的最优配置方案.所提方法充分考虑了来袭目标的不同类型、异构特性以及大气层内外防御的多元化火力运用方式;能够在具有混合整数非线性、约束强耦合、变量规模大等特征的防御武器配系场景下快速给出最优配置结果.并且,通过数值仿真验证了在对抗博弈条件下所提部署建模与智能优化方法的有效性与优越性.

红枫湖流域农业面源污染治理的生物地球化学垒体系构建初探

在点源污染得到有效控制后,流域内农业面源污染逐渐成为了湖库氮、磷等营养物质外源输入的主要贡献者。本研究选取红枫湖流域农田土壤为研究对象,对其添加改良剂并种植植物来构建生物地球化学垒,并对其氮、磷拦截效应进行了综合评估。研究结果表明,添加Al_(2)(SO_(4))_(3)、CaCl_(2)与钠基膨润土显著提高了土壤对NH_(4)^(+)-N、NO_(3)^(-)-N和磷的拦截率,降低其流失程度。其中,对土壤添加CaCl_(2)改性钠基膨润土并种植植被构建的生物地球化学垒,对NH_(4)^(+)-N、NO_(3)^(-)-N和磷的综合拦截效果最佳,截留率分别为87%、95%、93%。而添加了FeSO_(4)的土壤,NO_(3)^(-)-N的淋失程度增强,不宜选取。种植植物后,植物生长对土壤中氮和磷有一定的活化作用,导致模拟径流中NH_(4)^(+)-N和溶解性磷浓度较种植植物前升高,但是均低于对照组。而且种植植物后经改良的土壤单元有效磷(Olsen-P)较种植植物前显著降低,也反映出植物对土壤磷的活化利用。综上表明,通过对土壤添加Al_(2)(SO_(4))_(3)、CaCl_(2)与钠基膨润土并种植适生植物(黑麦草和白花三叶草)来构建生物地球化学垒,可以实现红枫湖小流域内的氮、磷等污染物拦截和植物生长两相促进,从而有效、持续拦截土壤氮、磷,降低其流失程度,对实现农业面源污染的可持续治理具有重要意义。

基于宁德市山-海资源本底区域生态安全格局构建研究

文章基于福建省宁德市特色的山-海生态本底,从生物多样性保护、水资源安全、城市安全韧性等方面着手,依据“识别生态源地→构建阻力面→提取生态廊道→构建生态安全格局”的研究思路,通过GIS叠加分析评价,识别出90余处重要生态源地,面积5328.6 km^(2),占宁德市域国土面积的24.6%;利用水系安全法、最小累积阻力方法,提取了18条生态廊道,构建了宁德市山-海生态安全格局。此外,划分出25余处生态障碍点,为下一步生态修复工作提供了一定的依据。

基于数值仿真计算的高速铁路声屏障长度对插入损失的影响

在当前高速铁路降噪措施中,声屏障最为普遍和有效,其中声屏障设置高度是主要设计参数,而声屏障设置长度和位置,则一般根据经验结合简单计算选取,声屏障长度及预测点位置对插入损失变化的影响考虑较少。根据Kurze点声源绕射声衰减理论推导有限长声屏障对列车线声源插入损失的理论算法,对比分析声屏障长度、高度变化对不同位置预测点声屏障插入损失的影响。研究结论如下:(1)随着声屏障长度增加,各预测点位置尤其声屏障两端附近,声屏障插入损失变大;(2)采取加高、延长声屏障措施对于插入损失值及空间分布影响不同,应根据预测点位置情况合理选择声屏障优化措施;(3)半无限长声屏障端部加长50 m后,插入损失变化量较为明显的区域位于声屏障端部水平距离110 m、与线路中心线距离130 m范围内。

半夏泻心汤治疗化疗性肠黏膜炎的治疗效果分析

目的:分析化疗性肠黏膜炎治疗中半夏泻心汤的治疗效果。方法:回顾性选取2020年2月-2023年2月本院化疗性肠黏膜炎患者100例,依据用药方法分为半夏泻心汤组、洛哌丁胺组两组,各50例。统计分析两组中医症候积分、肠道菌群相对丰度、肠黏膜屏障功能、血清炎症细胞因子水平、临床疗效、腹泻发生情况。结果:半夏泻心汤组患者的大便泄泻、腹痛腹胀、口干口苦、食欲不振、倦怠乏力、畏寒积分及中医症候总积分、肠球菌、肠杆菌、D-乳酸、ET、DAO、TNF-α、IL-1β、IL-6水平均低于洛哌丁胺组(P<0.05),乳酸杆菌、双歧杆菌、IL-10水平均高于洛哌丁胺组(P<0.05)。半夏泻心汤组患者的总有效率90.00%(45/50)高于洛哌丁胺组62.00%(31/50)(χ^(2)=10.746,P<0.05)。半夏泻心汤组患者的腹泻发生率6.00%(3/50)低于洛哌丁胺组50.00%(25/50)(χ^(2)=24.008,P<0.05)。结论:化疗性肠黏膜炎治疗中半夏泻心汤的治疗效果较洛哌丁胺好。

基于适老化理念的住宅设计探析

本文基于适老化理念,探讨了老年人住宅设计的基本原则,安全性原则,实用性原则,灵活性原则,健康性原则和便捷性原则。总结了公共区域、客厅、卧室、餐厨、卫生间等户内不同空间适老化设计的要点。通过遵循这些设计原则和设计要点,可以在住宅设计时为老年人创造安全舒适的住宅环境,提高他们的生活质量和幸福感。

计及FACTS装置的最大输电能力研究

输电能力是所有电力市场的参与者进行交易活动所必需的重要信息。文中提出了一种考虑常见 FACTS装置 (如 UPFC,TCPS,TCSC等 )的最大输电能力计算模型 ,在模型中考虑了电压水平、线路和设备过负荷等静态安全性约束条件 ,以及由于潮流方程解的鞍点分叉导致的电压稳定性约束条件。在算法上选用逐次线性化优化方法 ,并对每一个线性化子问题采用新算法——预测校正原始对偶对数障碍内点法求解。算例计算结果不仅说明了不同的 FACTS装置和安装位置对电网的输电能力有不同程度的影响 ,同时也表明了文中的模型和算法是有效的 ,具有一定的应用价值。

肉制品加工中关键控制点确定及栅栏技术应用的研究

在肉制品加工中通过对原料、辅料及加工工艺流程中微生物消长情况的研究，制定出相应的关键控制点（CCP）并应用栅栏技术控制微生物，延长产品货架期。