44
Sunday Night
SPS06: 8–10 p.m. On the Equilibrium Condition for the Movable
Piston
Poster – Jing Ji, Southeast University, Nanjing, Jiangsu 211189 China;
Jixuan Hou, Southeast University
It is not a sufficient equilibrium condition that the pressures are equal on
both sides of a smooth adiabatic movable piston. We consider a system
consisting of gas (with ideal gas model) which is partitioned into two parts
by an adiabatic movable piston. From the microscopic point of view, even
if the two parts are with equal pressures but different temperatures, energy
can still transfer from higher temperature gas to lower temperature gas
through the piston vibration, which is difficult to observe in macroscopic
system but very significant in mesoscopic system.
SPS07: 8–10 p.m. On the Resonance of the Air Column in a
Bottle
Poster – Yuchen Yang, Southeast University, Jiulong Lake Campus, South-
east Campus, Nanjing, Jiangsu 211189, China;
Yiru Lv, Chunxuan Hu, Southeast University
When pouring water into a thermos, a sound with rising frequency ap-
pears. We recorded and analyzed the sound wave. By using spectrum
analysis, we found that the sound exists in several different modes. After
comparing the standing wave theory with our measurements, we found
that they coincide with each other quite well. Our research shows that the
frequencies of the sound are also affected by penetrability and diffraction.
SPS08: 8–10 p.m. The Minimum Force Required to Separate
Two Alternating Books
Poster – Xudong Wu, Southeast University, Jiulong Lake Campus, Southeast
University Nanjing, Jiangsu 211189, China;
Yi Wang, Zi Liao, Mengdi Cao, Southeast University
It is difficult to separate two books with their pages overlapping alternately
with each other. To research the minimum force required to separate these
two alternating books, a dynamometer is used to measure the different
friction for different distances between overlapping line and spine L. We
found that the relation between maximum static friction and L shows a
power law, which coincides our scaling argument.
SPS09: 8–10 p.m. The Research of the Linear Oscillator
Poster – Cheng Chi, Southeast University, Jiulong Lake Campus, Southeast
University Nanjing, Jiangsu 211189, China;
The bizarre behavior of a type of nonlinear oscillator confused many
people. By analyzing the mechanical properties of a coil spring, we found
the equivalent of the nonlinear oscillator, a linear two-mode spring system.
By analyzing this linear model, we found that its solution can fit the experi-
mental data collected from the nonlinear oscillator, which means that the
motion of the nonlinear oscillator is linear indeed.
SPS10: 8–10 p.m. The Motion of a Falling Chain
Poster – Haoliang Su, Southeast University, Nanjing Jiulong Lake Campus,
Nanjing, Jiangsu 211189; China
Kai Wang, Yuzhao Yang, Southeast University
We assembled an experimental apparatus using a chain that is initially
attached by its two ends at the same height. We observed that, as one of
the ends is released, the acceleration of the chain tip is greater than the
acceleration of gravity. We posed our mechanical model which can fit the
experimental data very well.
SPS11: 8–10 p.m. Measurement of Planck’s Constant and
Plane Separation for NaCl Monocrystal
Poster – Misganaw Getaneh, University of Tennessee at Martin,115 Stephen-
son Rd., Martin, TN 38237;
Jordan Johnson, University of Tennessee at Martin
Diffraction of X-rays scattered by a NaCl monocrystal was used to measure
the spacing between two adjacent planes in a NaCl monocrystal and also
Planck’s constant. The x-rays were produced through bremsstrahlung
and K_α, K_β transitions when high-energy electrons were stopped by a
Molybdenum target. The first three orders of constructive interference of
the scattered K_α, K_β lines were analyzed to determine the separation d
of two adjacent planes of NaCl in the [1,0,0] direction. The crystal plane
spacing, according to this measurement is d=281±4 pm and the corre-
sponding edge length of a unit cell of NaCl is a_0=562±8 pm. These are
reasonably close to the literature values of d=282.01 pm and a_0=564.02
pm, respectively. Data of count rate versus scattering angle was obtained
for various accelerating voltages for the bremsstrahlung part of the x-ray
spectra. Analysis that is based on the displacement of the high energy
edge of the x-ray spectra with increase in the accelerating voltage and the
Duane-Hunt law were used to determine Planck’s constant h. Planck’s
constant is measured to have the value h=(6.8±0.2)×10
(-34)
Js, which is close
to the literature value of h=6.63× 10
(-34)
Js.
SPS12: 8–10 p.m. Space Balloon: Journey into the Stratosphere
Poster – Carlos Blanco,* Purdue University, Department of Physics, West
Lafayette, IN 47907;
Danielle Harper, Patrick A. Kelley, Cordero Magana, Vatsal Purohit, Purdue
University
Purdue University’s Society of Physics Students (SPS) conducted an investi-
gation of the Earth’s atmosphere by launching space balloons during the
spring 2014 semester. The experiment utilized a balloon that would carry a
4-6 lb. payload. This payload consisted of a GPS detector, radio transmit-
ter and two cameras to observe both the Earth’s surface and also to detect
Baryons. Additional sensors attached to the weather shield of the balloon
collected data on: altitude, pressure, humidity and ambient light. The space
balloon was launched on two separate occasions to reach a height of over
80,000 ft. or greater than 15 miles (~ 25 Km) and traveled over 60 miles
before parachuting to the Earth. Data on each variable collected as a func-
tion of altitude and position will be presented along with pictures from the
flight.
*Sponsored by A. Hirsch, Purdue University
SPS13: 8–10 p.m. Concentration-dependent Luminescent of
GdF3: Yb3+, Er3+
Poster – Chufeng Liu,* Sun Yat-Sen University, No. 135 West Xingang Road,
Guangzhou City, Guangzhou, Guangdong 510275, China; 444394693@
qq.com
Jiawei Yan, Sun Yat-Sen University
Yb3+, Er3+ co-doped rare-earth fluorides have attracted great attention
due to their excellent upconversion luminescent properties and research
on Yb3+, Er3+ co-doped GdF3 nanocrystals are also flourishing. However,
concentration effects of Yb3+ and Er3+ on luminescent properties were
seldom studied. In this paper, a series of GdF3:20% Yb3+,x% Er3+ (x = 1,
2, 3, 5) and GdF3:y%Yb3+,2%Er3+ (y = 10, 20, 40, 60, 98) nanoparticles
(NPs) were prepared by a hydrothermal method. The structural properties
of the products were characterized by X-ray diffraction, scanning elec-
tronic microscopy and transmission electron microscopy. . Luminescence
spectra under 980 nm and 390 nm excitation of GdF3:y% Yb3+,Er3+ NPs
show that RGR is positively proportional to the Yb3+ concentration. The
corresponding energy transfer mechanisms were illustrated. The results
show that GdF3:Yb3+,Er3+ NPs are promising materials in photovoltaic,
display panel and bio-imaging.
*Sponsored by Fuli Zhao
