Removal of aqueous phenol compound by vacuum membrane distillation

1.IntroductionPhenolisanimportantchemicalindustrymaterial,butitalsoaboundswithserioushazardtoenvironmentandthreatstohumanhealth.Rigidruleshavebeenmadeoutonthephenoldischargeconcentration.Researchesonthetreatmentofphenolwastewaterwerecarriedoutinvariouscountries[1-5].Membraneseparationmethodsincludingreverseosmosis,ultrafiltrationandpervaporationhaveattractedmuchattentionforphenolwastewatertreatment,withcelluloseacetate(CA)membraneemployedmostly[6].Membranedistillationisanewmembraneseparation…     

我国课堂教学评价研究概况、问题与设想

概述我国课堂教学评价研究的现状,包括对课堂教学本质和价值取向、评价标准和指标、教学评价方法的研究。分析我国课堂教学评价存在的问题,包括局限于理论构建,缺少课堂实证研究;缺乏对课堂教学客观、准确、精细的描述;局限于评价标准与指标法,缺乏有效方法的综合运用。提出今后研究的设想,包括进行课堂教学的实证研究,提供对课堂教学的多角度、多类型的描述,同时建立教学评价标准指标体系和行为分类系统,综合使用定量方法和质的方法。     

Investigation of blood pulse PPG signal regulation on toe effect of body posture and lower limb height

Objective: To study the regulation of blood pulse volume via photoplethysmography (PPG) signal detected from toe, while the lower limb is passively raised in different height positions. Methods: Use a modified non-invasive PPG technique to detect the blood pulse signal on toe with infrared (IR) photo sensor. A protocol consisting of two postures, i.e., supine and 45° reclining, was designed to conduct laboratory trial in this study. During the period of performing the protocol of these postures, the lower limb was passively raised from the heights of 10 cm to 60 cm randomly and individually with sponge blocks underneath the foot. Results: In the supine posture, the higher the foot was passively raised, the more the blood PPG signal decreased. In the 45° reclining posture, the blood PPG signal increased at the beginning and then decreased in the foot height position from 10 cm to 60 cm. In both postures the normalized AC signal changes significantly while the normalized DC signal changes little. Conclusion: The toe PPG signals can obviously indicate the regulated blood volume change with the designated postural procedures due to the heart level position.     

爸爸忘了你还只是个孩子

本期推出两篇短小精美的文章,表达了父爱的温馨,有兴趣的读者朋友不妨将它们作为范文来诵渎。     

新时期加强大学生诚信教育路径思索

诚信是中华民族的优良传统美德。大学生做为我国知识文化水平较高的群体,大学生的诚信教育对创建社会主义和谐社会有着重要的意义。随着时代的发展,思想观念发生了极大的改变。本文针对大学生的诚信教育路径,提出自己的想法和意见。     

高校教师隐性知识转移与共享因素分析

利用对高校教师隐性知识转移的调查,分析了高校教师隐性知识转移的现状、影响因素及对绩效的影响.分析表明,个人接触是最好的隐性知识转移方式,而对人际关系忠诚、情感距离及团队的目标、氛围、领导风格是影响团队成员隐性知识共享的重要因素;在隐性知识共享对绩效的影响方面,普遍认为,隐性知识共享能够增加团队成员科研成果的数量、质量,节约科研时间、成本,同时也有利于团队成员获得更多的发展机会.     

Gravity-oriented microfluidic device for uniform and massive cell spheroid formation

We propose a simple method for forming massive and uniform three-dimensional (3-D) cell spheroids in a multi-level structured microfluidic device by gravitational force. The concept of orienting the device vertically has allowed spheroid formation, long-term perfusion, and retrieval of the cultured spheroids by user-friendly standard pipetting. We have successfully formed, perfused, and retrieved uniform, size-controllable, well-conditioned spheroids of human embryonic kidney 293 cells (HEK 293) in the gravity-oriented microfluidic device. We expect the proposed method will be a useful tool to study in-vitro 3-D cell models for the proliferation, differentiation, and metabolism of embryoid bodies or tumours.     

Shrink-film microfluidic education modules: Complete devices within minutes

As advances in microfluidics continue to make contributions to diagnostics and life sciences, broader awareness of this expanding field becomes necessary. By leveraging low-cost microfabrication techniques that require no capital equipment or infrastructure, simple, accessible, and effective educational modules can be made available for a broad range of educational needs from middle school demonstrations to college laboratory classes. These modules demonstrate key microfluidic concepts such as diffusion and separation as well as "laboratory on-chip" applications including chemical reactions and biological assays. These modules are intended to provide an interdisciplinary hands-on experience, including chip design, fabrication of functional devices, and experiments at the microscale. Consequently, students will be able to conceptualize physics at small scales, gain experience in computer-aided design and microfabrication, and perform experiments-all in the context of addressing real-world challenges by making their own lab-on-chip devices.     

Perfusion systems that minimize vascular volume fraction in engineered tissues

This study determines the optimal vascular designs for perfusing engineered tissues. Here, "optimal" describes a geometry that minimizes vascular volume fraction (the fractional volume of a tissue that is occupied by vessels) while maintaining oxygen concentration above a set threshold throughout the tissue. Computational modeling showed that optimal geometries depended on parameters that affected vascular fluid transport and oxygen consumption. Approximate analytical expressions predicted optima that agreed well with the results of modeling. Our results suggest one basis for comparing the effectiveness of designs for microvascular tissue engineering.     

改良大脑真的好吗?

人类有能力测定和操纵基因,这一革命激起了各种各样的伦理争议.同样具有深远意义的脑科学革命,引起的注意却少得让人吃惊.