779 research outputs found
A Study on Teaching English at SMPN 1 Banyuputih Situbondo
Abstract:The purpose of the research is to find out the question of: " how does the English teacher teaches the four language skill: listening, reading, speaking and writing in A class students of second grade of SMPN 1 Banyuputih Situbondo. The study was conducted through descriptive qualitative design, because the data that are going to analyze is in the form of descriptions. In this study, interview and observation check list are used to complete the data. The population of this research are the English teacher of A class and the A class students of second grade in SMPN 1 Banyuputih Situbondo which consist of 32 students. The result of this research shows that The English teacher at SMPN 1 Banyuputih Situbondo evaluated the student’s achievement. The teacher used two techniques to evaluate the students. Those are: written test and oral test. From the evaluations that give by the teacher, we can know the student’s achievement in English. In this study, the researcher find that the A class students of second grade in SMPN 1 Banyuputih Situbondo can interact fluently with their friends in the classroom in English, and in recent years they got won several English competitions that held in Situbondo city and East Java, such as ; speech, telling story, essay, and news anchor. From the student’s achievement above, the researcher found that teaching English at second grade of SMPN 1 Banyupuitih Situbondo already fulfilled the national standard of teaching English requirement. Key words: Teaching English, Students’ interest, Students’ Achievemen
pH-Mediated Regulation of Polymer Transport Through SiN Pores
We characterize the pH controlled polymer capture and transport thorough
silicon nitride (SiN) pores subject to protonation. A charge regulation model
able to reproduce the experimental zeta potential of SiN pores is coupled with
electrohydrodynamic polymer transport equations. The formalism can
quantitatively explain the experimentally observed non-monotonic pH dependence
of avidin conductivity in terms of the interplay between the electroosmotic and
electrophoretic drag forces on the protein. We also scrutinize the DNA
conductivity of SiN pores. We show that in the low pH regime where the
amphoteric pore is cationic, DNA-pore attraction acts as an electrostatic trap.
This provides a favorable condition for fast polymer capture and extended
translocation required for accurate polymer sequencing
Ionic current inversion in pressure-driven polymer translocation through nanopores
We predict streaming current inversion with multivalent counterions in
hydrodynamically driven polymer translocation events from a
correlation-corrected charge transport theory including charge fluctuations
around mean-field electrostatics. In the presence of multivalent counterions,
electrostatic many-body effects result in the reversal of the DNA charge. The
attraction of anions to the charge-inverted DNA molecule reverses the sign of
the ionic current through the pore. Our theory allows for a comprehensive
understanding of the complex features of the resulting streaming currents. The
underlying mechanism is an efficient way to detect DNA charge reversal in
pressure-driven translocation experiments with multivalent cations.Comment: This version is accepted for publication in Physical Review Letter
Electrostatic correlations in inhomogeneous charged fluids beyond loop expansion
Electrostatic correlation effects in inhomogeneous symmetric electrolytes are
investigated within a previously developed electrostatic self-consistent (SC)
theory (R.R. Netz and H. Orland, Eur. Phys.J. E 11, 301 (2003)). To this aim,
we introduce two computational approaches that allow to solve the SC equations
beyond the loop expansion. Both approaches can handle the case of
dielectrically discontinuous boundaries where the one-loop theory is known to
fail. By comparing the theoretical results obtained from these schemes with the
results of the MC simulations that we ran for ions at neutral single dielectric
interfaces as well as with previous MC data for charged interfaces, we first
show that the weak coupling (WC) Debye-Huckel (DH) theory remains
quantitatively accurate up to the bulk ion density rhob=0.01 M, whereas the SC
theory exhibits a good quantitative accuracy up to rhob=0.2 M. Then, we derive
from the perturbative SC scheme the one-loop theory of asymmetrically
partitioned salt systems around a dielectrically homogeneous charged surface.
It is shown that correlation effects originate in these systems from a
competition between the salt screening loss at the interface driving the ions
to the bulk region, and the interfacial counterion screening excess attracting
them towards the surface. In the case of weak surface charges, the interfacial
salt screening loss is the dominant effect. As a result, correlations decrease
the MF density of both coions and counterions. With increasing surface charge,
the surface-attractive counterion screening excess starts to dominate, and
correlation effects amplify in this regime the MF density of both type of ions.
We also show that at a characteristic value of the electrostatic coupling
parameter, electrostatic correlations result in a charge inversion effect
Comment on "Nonlocal statistical field theory of dipolar particles in electrolyte solutions" by Y.A. Budkov
The article by Budkov introduces a nonlocal field-theoretic model of
solvent-explicit electrostatics. Despite giving a detailed introduction to the
early literature on the topic, the article misses out on a series of articles
that we published several years ago. Consequently, the manuscript essentially
rederives without mention several results that were derived by us for the first
time
Influence of Disorder Strength on Phase Field Models of Interfacial Growth
We study the influence of disorder strength on the interface roughening
process in a phase-field model with locally conserved dynamics. We consider two
cases where the mobility coefficient multiplying the locally conserved current
is either constant throughout the system (the two-sided model) or becomes zero
in the phase into which the interface advances (one-sided model). In the limit
of weak disorder, both models are completely equivalent and can reproduce the
physical process of a fluid diffusively invading a porous media, where
super-rough scaling of the interface fluctuations occurs. On the other hand,
increasing disorder causes the scaling properties to change to intrinsic
anomalous scaling. In the limit of strong disorder this behavior prevails for
the one-sided model, whereas for the two-sided case, nucleation of domains in
front of the invading front are observed.Comment: Accepted for publication in PR
Bit Level Correlations in Some Pseudorandom Number Generators
We present results of extensive bit level tests on some pseudorandom number
generators which are commonly used in physics applications. The generators have
first been tested with an extended version of the -tuple test. Second, we
have developed a novel {\it cluster test} where a physical analogy of the
binary numbers with the two dimensional Ising model has been utilized. We
demonstrate that the new test is rather powerful in finding periodic
correlations on bit level. Results of both test methods are presented for each
bit of the output of the generators. Some generators exhibit clear bit level
correlations but we find no evidence of discernible correlations for
generators, which have recently produced systematic errors in Monte Carlo
simulations.Comment: University of Helsinki preprint HU-TFT-93-4
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