Nanopore Surface Charge Sensing with Ion-Step Method

Author(s):  
Jing Yang ◽  
Songyue Chen
Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1690
Author(s):  
Songyue Chen ◽  
Hepeng Dong ◽  
Jing Yang

Surface potential and surface charge sensing techniques have attracted a wide range of research interest in recent decades. With the development and optimization of detection technologies, especially nanosensors, new mechanisms and techniques are emerging. This review discusses various surface potential sensing techniques, including Kelvin probe force microscopy and chemical field-effect transistor sensors for surface potential sensing, nanopore sensors for surface charge sensing, zeta potentiometer and optical detection technologies for zeta potential detection, for applications in material property, metal ion and molecule studies. The mechanisms and optimization methods for each method are discussed and summarized, with the aim of providing a comprehensive overview of different techniques and experimental guidance for applications in surface potential-based detection.


2001 ◽  
Vol 124 (2) ◽  
pp. 288-296 ◽  
Author(s):  
S. Morris ◽  
R. J. K. Wood ◽  
T. J. Harvey ◽  
H. E. G. Powrie

Electrostatic charge sensing technology has been used to monitor adhesive wear in oil lubricated contacts. Previous work in this area demonstrated that “precursor” charge events may be detected prior to the onset of scuffing. Possible charging mechanisms associated with the precursor events were identified as tribocharging, surface charge variation, exo-emissions and debris generation. This paper discusses the proposed charging mechanisms and details a series of investigative tests using an adapted pin-on-disc (PoD) rig. The PoD tests focused on surface charge variation effects and were of two types, non-contact, where different materials were inserted in the disc, and controlled scuffing tests.


2014 ◽  
Vol 116 (7) ◽  
pp. 074511 ◽  
Author(s):  
S. Kumar ◽  
R. Esfandyarpour ◽  
R. Davis ◽  
Y. Nishi

Author(s):  
N.J. Tao ◽  
J.A. DeRose ◽  
P.I. Oden ◽  
S.M. Lindsay

Clemmer and Beebe have pointed out that surface structures on graphite substrates can be misinterpreted as biopolymer images in STM experiments. We have been using electrochemical methods to react DNA fragments onto gold electrodes for STM and AFM imaging. The adsorbates produced in this way are only homogeneous in special circumstances. Searching an inhomogeneous substrate for ‘desired’ images limits the value of the data. Here, we report on a reversible method for imaging adsorbates. The molecules can be lifted onto and off the substrate during imaging. This leaves no doubt about the validity or statistical significance of the images. Furthermore, environmental effects (such as changes in electrolyte or surface charge) can be investigated easily.


1983 ◽  
Vol 49 (01) ◽  
pp. 024-027 ◽  
Author(s):  
David Vetterlein ◽  
Gary J Calton

SummaryThe preparation of a monoclonal antibody (MAB) against high molecular weight (HMW) urokinase light chain (20,000 Mr) is described. This MAB was immobilized and the resulting immunosorbent was used to isolate urokinase starting with an impure commercial preparation, fresh urine, spent tissue culture media, or E. coli broth without preliminary dialysis or concentration steps. Monospecific antibodies appear to provide a rapid single step method of purifying urokinase, in high yield, from a variety of biological fluids.


2010 ◽  
Vol 13 (3) ◽  
pp. 78-87
Author(s):  
Hoai Cong Huynh

The numerical model is developed consisting of a 1D flow model and the morphological model to simulate the erosion due to the water overtopping. The step method is applied to solve the water surface on the slope and the finite difference method of the modified Lax Scheme is applied for bed change equation. The Meyer-Peter and Muller formulae is used to determine the bed load transport rate. The model is calibrated and verified based on the data in experiment. It is found that the computed results and experiment data are good agreement.


2011 ◽  
pp. 57-78
Author(s):  
I. Pilipenko

The paper analyzes shortcomings of economic impact studies based mainly on input- output models that are often employed in Russia as well as abroad. Using studies about sport events in the USA and Olympic Games that took place during the last 30 years we reveal advantages of the cost-benefit analysis approach in obtaining unbiased assessments of public investments efficiency; the step-by-step method of cost-benefit analysis is presented in the paper as well. We employ the project of Sochi-2014 Winter Olympic and Paralympic Games in Russia to evaluate its efficiency using cost-benefit analysis for five accounts (areas of impact), namely government, households, environment, economic development, and social development, and calculate the net present value of the project taking into account its possible alternatives. In conclusion we suggest several policy directions that would enhance public investment efficiency within the Sochi-2014 Olympics.


Sign in / Sign up

Export Citation Format

Share Document