U.S. patent application number 13/644957 was filed with the patent office on 2013-04-11 for heteronuclear radioisotope nanoparticle of core-shell structure and preparation method thereof.
This patent application is currently assigned to KOREA ATOMIC ENERGY RESERACH INSTITUTE. The applicant listed for this patent is KOREA ATOMIC ENEGY RESEARCH INSTITUTE. Invention is credited to Seong-Ho Choi, Jin-Hyuck Jung, Sung-Hee Jung, Jong-bum Kim, Jinho Moon.
Application Number | 20130087748 13/644957 |
Document ID | / |
Family ID | 47953793 |
Filed Date | 2013-04-11 |
United States Patent
Application |
20130087748 |
Kind Code |
A1 |
Jung; Sung-Hee ; et
al. |
April 11, 2013 |
HETERONUCLEAR RADIOISOTOPE NANOPARTICLE OF CORE-SHELL STRUCTURE AND
PREPARATION METHOD THEREOF
Abstract
Heteronuclear radioisotope nanoparticle of core-shell structure
and a preparation method thereof are provided. The Heteronuclear
radioisotope nanoparticle of core-shell structure comprising core
of two different radioisotopes selected from a group consisting of
.sup.198Au, .sup.63Ni, .sup.110mAg, .sup.64Cu, .sup.60Co,
.sup.192Ir and .sup.103Pd, and a shell comprising Si0.sub.2
surrounding the core. The Heteronuclear radioisotope nanoparticle
of core-shell can be used as a tracer for the purpose of detecting
variation of volume ratio or for the evaluation of the behavior
characteristic of a water resource, based on information about
phase ratio in the flow of multiphase fluid existing in a process
which is operated under extreme condition such as high temperature
and/or high pressure conditions.
Inventors: |
Jung; Sung-Hee; (Daejeon,
KR) ; Choi; Seong-Ho; (Daejeon, KR) ; Kim;
Jong-bum; (Daejeon, KR) ; Moon; Jinho;
(Daejeon, KR) ; Jung; Jin-Hyuck; (Daejeon,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
INSTITUTE; KOREA ATOMIC ENEGY RESEARCH |
Daejeon |
|
KR |
|
|
Assignee: |
KOREA ATOMIC ENERGY RESERACH
INSTITUTE
Daejeon
KR
|
Family ID: |
47953793 |
Appl. No.: |
13/644957 |
Filed: |
October 4, 2012 |
Current U.S.
Class: |
252/625 ;
427/551; 977/890; 977/902 |
Current CPC
Class: |
B01J 13/18 20130101;
G21H 5/02 20130101; Y10S 977/902 20130101; G21G 4/06 20130101; B82Y
40/00 20130101; B05D 1/00 20130101; G01F 1/7042 20130101 |
Class at
Publication: |
252/625 ;
427/551; 977/902; 977/890 |
International
Class: |
B05D 1/00 20060101
B05D001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 5, 2011 |
KR |
10-2011-0101302 |
Claims
1. A Heteronuclear radioisotope nanoparticle of core-shell
structure, comprising a core comprising two different radioisotopes
selected from a group consisting of .sup.198Au, .sup.63Ni,
.sup.110mAg, .sup.64Cu, .sup.60Co, .sup.192Ir and .sup.103Pd, and a
shell comprising SiO.sub.2 surrounding the core.
2. The heteronuclear radioisotope nanoparticle of core-shell
structure as set forth in claim 1, wherein the core comprise a
combination of .sup.198Au and one of the rest of the group except
.sup.198Au.
3. The heteronuclear radioisotope nanoparticle of core-shell
structure as set forth in claim 1, wherein the two different
radioisotepes of the core emit radiations distinguished from each
other.
4. A method for preparing the heteronuclear radioisotope
nanoparticle of core-shell structure as set forth in claim 1, the
method comprising: (step 1) preparing cores of the heteronuclear
nanoparticle by dispersing two different types of atoms selected
from a group consisting of Au, Ni, Ag, Cu, Co, Ir and Pd in water,
and stabilizing the result with colloid stabilizer; (step 2)
preparing nanoparticle with core-shell structure by coating the
nanoparticle core prepared at step 1 with SiO.sub.2 repeatedly for
several times; (step 3) removing the colloid stabilizer remaining
in the core-shell structure prepared at step 2 by calcining the
prepared nanoparticle; and (step 4) activating the nanoparticle
within the core by irradiating neutron onto the nanoparticle with
the core-shell structure prepared at step 3.
5. The method as set forth in claim 4, comprising applying the
colloid stabilizer to the nanoparticle by irradiating radiation to
stabilize the nanoparticle core of step 1.
6. The method as set forth in claim 4, wherein the colloid
stabilizer of step 1 is polyvinylpyrrolidone.
7. The method as set forth in claim 4, wherein the calcining for
removing the colloid stabilizer in step 3 is performed under
nitrogen flow at 500-600.degree. C.
8. The heteronuclear radioisotope nanoparticle of core-shell
structure as set forth in claim 1, which is used as a tracer for
the purpose of detecting movement of multi phase fluid existing in
a process operated under extreme condition including high
temperature and/or high pressure, or for the purpose of evaluating
behavior of water resource.
9. The heteronuclear radioisotope nanoparticle of core-shell
structure as set forth in claim 8, wherein ratios of respective
phases are measured through flow detection on the multi phase
fluid, and information regarding volume ratio of the multi phase
fluid is obtained therefrom.
10. The heteronuclear radioisotope nanoparticle of core-shell
structure as set forth in claim 8, wherein the fluid existing in
the process is dual phase fluid.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This patent application claims the benefit of priority from
Korean Patent Application No. 10-2011-0101302, filed on Oct. 5,
2011, the contents of which are incorporated herein by reference in
its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to heteronuclear radioisotope
nanoparticle of core-shell structure and a preparation method
thereof.
[0004] 2. Description of the Related Art
[0005] Radioisotope refers to a matter in which atomic nucleus
thereof emits radioactive rays without requiring external influence
such as pressure, temperature, chemical treatment, to turn into
different type of atomic nucleus. The generally available
radioisotope includes .sup.198Au, .sup.63Ni, .sup.110mAg,
.sup.64Cu, .sup.60Co, .sup.192Ir, or .sup.103Pd.
[0006] In the industrial application, open radioisotope generally
serves as a tracer. That is, by tracing radioactive rays emitted
from the radioisotope by a measuring device, it is possible to
analyze the behavior of a material. Since gamma (y) ray does not
carry electricity nor does it have mass, this has less interaction
with the matter and less energy loss when passing through the
matter compared to the other radioactive rays. Further, since
.gamma. ray has strong penetrating power irradiated from the
radioactive nanoparticles, this can penetrate through the wall of
the vessel containing the fluid to easily detect the target of
detection existing in the fluid.
[0007] The metal nanoparticles are generally made by electric
bombardment, sodium/halide flame and encapsulation technology
(SFE), chemical reduction, or electric reduction. However, the
metal nanoparticles made by these methods have rather irregular
granularity of the particles, and mass production is rather
difficult at room temperature. Meanwhile, the radiation reduction
relates to irradiating radioactive ray onto metal ion solution and
generating metal nanoparticles using free radicals generated from
the solution. This method has the advantages of no side reaction,
and mass-productability at room temperature. By way of example,
Reference 1 (S. H. Choi et al.) report about fabricating precious
metal nanoparticles using radiation reduction, and using these as
catalysts. Further, S. H. Choi et al. have conducted a study
regarding radioactivation of the nanoparticles by irradiating
neutrons thereon. Further, Reference 2 (S. D. Oh et al.) researched
about loading precious nanoparticles in a carbon nano-tube to use
as a fuel battery, in which the researchers studied about
synthesizing nanoparticle alloy.
[0008] The researchers of References 1 and 2 used surfactant or
soluble polymer as colloid stabilizer or nanoparticles loaded in a
specific carrier to stabilize the nanoparticles. However, in
fabricating radioactive nanoparticles, there is a risk that the
colloid stabilizer itself can be activated. Therefore, it is
required that the use of colloid stabilizer be minimized or the
stabilizer be completely eliminated after use, in order to use the
radioactive nanoparticles as a tracer. However, if the colloid
stabilizer is eliminated in the fabricating process of the metal
nanoparticles, aggregation can occur among the nanoparticles due to
considerably low mass ratio to surface area, and as a result, the
nanoparticles grow and cannot serve as a tracer for flow detection
of a target of the research. In order to overcome the problem
explained above, a technique to coat the metal nanoparticles with
SiO.sub.2 which is not activated even by the radiation of the
neutron (Reference 3).
[0009] Meanwhile, Reference 4 (C. P. Winlove et al.) studied about
attaching iodine-125(.sup.125I) as radioisotope to gold (Au)
nanoparticle and mixing with natural polymer such as protein
peptide to use this as a tracer. However, in implementing this to
high temperature and high pressure industrial process, there is a
problem that the radioisotope (.sup.125I) is separated from the
gold nanoparticle. Further, Reference 5 (A.V. S. Roberts) and 6 (M.
K. Pratten) prepared colloid particles by, first, chelating
.sup.125I and .sup.14C to polyvinylpyrrolidone as a stabilizer, and
then coupling the result to colloid gold to use it as a bio-tracer.
However, since radioisotopes such as .sup.125I and .sup.14C are
adsorbed onto soil and emits low energy of radiation, it is
difficult to detect the behavior in the soil sample, not to mention
the flow in the industrial processing.
[0010] Accordingly, considering the fact that the measurement
result with a single radioactive particle particularly on the multi
phase flow does not provide information about phase ratio, the
present inventors prepared heteronuclear radioisotope nanoparticle
with core-shell structure in which two different types of elements
as the cores are coated with SiO.sub.2, to thus obtain information
about the phase ratio on the multi phase flow and calculate the
volume ratio, and was confirmed that the prepared nanoparticle can
be used as a tracer to detect the flow behavior of the fluid, and
completed the invention.
[0011] [Reference 1] S.-H Choi, Y.-P. Zhang, A.Gopalan, K.-P. Lee,
H.-D. Kang, Preparation of Catalytically Efficient Precious
Metallic Colloids by .gamma.-Irradiation and Characterization,
Colloids Surfaces A, 256, 165-170 (2005).
[0012] [Reference 2] S.-D. Oh, B.-K. So, S.-H. Choi, A.Gopalan,
K.-P. Lee, K. R. Yoon, I. S. Choi, Dispersing of Ag, Pd, and Pt--Ru
alloy nanoparticles on single-walled carbon nanotubes by
y-irradiation, Mater. Lett., 59, 1121-1124 (2005).
[0013] [Reference 3] KR 10-2010-0034499 A 2010.04.01, p. 4, lines
19-24
[0014] [Reference 4] C.P. Winlove, J. Davis, A. Iacovides, A.
Chabanel, Radioactive Gold Colloid as a Tracer of Macromolecules
Transport, Biotechnology, 18, 569-578 (1981).
[0015] [Reference 5] A.V.S. Roberts, K. E. Williams, and J. B.
LLoyd, "The Pinocytosis of .sup.125I-Labelled
Poly(vinylpyrrolidone), [.sup.14C]Sucrose and Colloidal [198Au]Gold
by Rat Yolk Sac Cultured in vitro, Biochem. J. 168, 239-244
(1977).
[0016] [Reference 6] M. K. Pratten, and J.B. Lloyd, Effects of
Temperature, Metabolic Inhibitors and Some Other Factors on
Fluid-Phase and Adsorptive Pinocytosisi by Rat Peritoneal
Macrophages, Biochem. J., 180, 567-571 (1979).
SUMMARY OF THE INVENTION
[0017] The present invention has been made to overcome the
above-mentioned disadvantages in the related art, and accordingly,
an object of the present invention is to provide heteronuclear
radioisotope nanoparticle of core-shell structure which is stable
to be used as a tracer for detecting a variation in the volume
ratio through measurement of phase ratio of multi phase flow.
[0018] Another object of the present invention is to provide a
method for preparing said heteronuclear radioisotope nanoparticle
of core-shell structure. In one embodiment, Heteronuclear
radioisotope nanoparticle of core-shell structure is provided,
which may include a core comprising two different radioisotopes
selected from a group consisting of .sup.198Au, .sup.63Ni,
.sup.110nAg, .sup.64Cu, .sup.60CO, .sup.192Ir and .sup.103Pd, and a
shell comprising SiO.sub.2 surrounding the core. In another
embodiment, a method for preparing Heteronuclear radioisotope
nanoparticle of core-shell structure is provided, which may include
(step 1) preparing core of the heteronuclear nanoparticle by
dispersing two different types of atoms selected from a group
consisting of Au, Ni, Ag, Cu, Co, Ir and Pd in water, and
stabilizing the result with colloid stabilizer, (step 2) preparing
nanoparticle with core-shell structure by coating the nanoparticle
core prepared at step 1 with SiO.sub.2 repeatedly for several
times; (step 3) removing the colloid stabilizer remaining in the
core-shell structure prepared at step 2 by calcining the prepared
nanoparticle, and (step 4) activating the nanoparticle within the
core by irradiating neutron onto the nanoparticle with the
core-shell structure prepared at step 3.
[0019] According to the heteronuclear radioisotope nanoparticle of
core-shell structure of an embodiment, since two different
radioisotopes are integrated into one core, the nanoparticle have
less oxidization or agglomeration compared to single nanoparticle,
and accordingly provide higher safety. Further, since the
Heteronuclear radioisotope nanoparticle of core-shell structure
according to an embodiment emit heterogeneous gamma rays, the
nanoparticle can be used as a tracer for the purpose of detecting
flow of fluid existing in a multi phase process which is operated
under extreme condition such as high temperature and/or high
pressure operation, and for the detection of variation in the
volume ratio or evaluation of behavior characteristic of water
resource through phase ratio measurement.
[0020] The Heteronuclear radioisotope nanoparticle of core-shell
structure according to an embodiment is coated with SiO.sub.2 which
is not activated by the irradiation of neutron, agglomeration of
nanoparticles due to removal of colloid stabilizer can be
prevented. Further, due to the minimum possibility that the
remaining colloid stabilizer is activated during activation of the
nanoparticle in the process such as removal of colloid stabilizer,
the quantity and quality of the information obtainable from the
radiation of the radioisotope are ensured.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The above and/or other aspects of what is described herein
will be more apparent by describing certain exemplary embodiments
with reference to the accompanying drawings, in which:
[0022] FIG. 1 is a schematic view illustrating a process of
preparing heteronuclear radioisotope nanoparticle of core-shell
structure according to the present invention;
[0023] FIG. 2 is a TEM image of Au--Ag core nanoparticle stabilized
with polvinylpyrrolidone prepared at Example 1 according to the
present invention, in which mole ratio of core nanoparticle (i.e.,
Au and Ag) is 1:1;
[0024] FIG. 3 is a TEM image of Au--Ag@ SiO.sub.2, which is the
heteronuclear radioisotope nanoparticle of core-shell structure
prepared at Example 1 according to the present invention;
[0025] FIG. 4 is a TEM image of Au--Ni core nanoparticle stabilized
with polyvinylpyrrolidone prepared at Example 2 according to the
present invention, in which mole ratio of core nanoparticle (i.e.,
Au and Ni) is 1:1;
[0026] FIG. 5 is a TEM image of Au--Co core nanoparticle stabilized
with polyvinylpyrrolidone prepared at Example 3 according to the
present invention, in which mole ratio of core nanoparticle (i.e.,
Au and Co) is 1:1;
[0027] FIG. 6 is a TEM image of Au--Cu core nanoparticle stabilized
with polyvinylpyrrolidone prepared at Example 4 according to the
present invention, in which mole ratio of core nanoparticle (i.e.,
Au and Cu) is 1:1;
[0028] FIG. 7 is a TEM image of Au--Ir core nanoparticle stabilized
with polyvinylpyrrolidone prepared at Example 5 according to the
present invention, in which mole ratio of core nanoparticle (i.e.,
Au and Ir) is 1:1;
[0029] FIG. 8 is a result of EDS measurement of Au--Ag core
nanoparticle stabilized with polvinylpyrrolidone prepared at
Example 1 according to the present invention, in which mole ratio
of core nanoparticle (i.e., Au and Ag) is 1:1;
[0030] FIG. 9 is a result of EDS measurement of Au--Ag@SiO.sub.2,
which is the heteronuclear radioisotope nanoparticle of core-shell
structure prepared at Example 1 according to the present
invention;
[0031] FIG. 10 is a result of EDS measurement of Au--Ni core
nanoparticle stabilized with polvinylpyrrolidone prepared at
Example 2 according to the present invention, in which mole ratio
of core nanoparticle (i.e., Au and Ni) is 1:1;
[0032] FIG. 11 is a result of EDS measurement of Au--Co core
nanoparticle stabilized with polvinylpyrrolidone prepared at
Example 3 according to the present invention, in which mole ratio
of core nanoparticle (i.e., Au and Co) is 1:1;
[0033] FIG. 12 is a result of EDS measurement of Au--Cu core
nanoparticle stabilized with polvinylpyrrolidone prepared at
Example 4 according to the present invention, in which mole ratio
of core nanoparticle (i.e., Au and Cu) is 1:1;
[0034] FIG. 13 is a result of EDS measurement of Au--Ir core
nanoparticle stabilized with polvinylpyrrolidone prepared at
Example 5 according to the present invention, in which mole ratio
of core nanoparticle (i.e., Au and Ir) is 1:1;
[0035] FIG. 14 is a result of ELS measurement of Au--Ag core
nanoparticle stabilized with polvinylpyrrolidone prepared at
Example 1 according to the present invention, in which mole ratio
of core nanoparticle (i.e., Au and Co) is 1:1, and average
granularity (D)=192.4 nm;
[0036] FIG. 15 is a result of ELS measurement of Au--Ag
Au--Ag@SiO.sub.2, which is the heteronuclear radioisotope
nanoparticle of core-shell structure prepared at Example 1
according to the present invention, in which average granularity
(D)=111.1 nm;
[0037] FIG. 16 is a result of ELS measurement of Au--Co core
nanoparticle stabilized with polvinylpyrrolidone prepared at
Example 3 according to the present invention, in which mole ratio
of core nanoparticle (i.e., Au and Co) is 1:1, and average
granularity (D)=107.2 nm;
[0038] FIG. 17 is a result of UV-visible spectrophotometer of
Au--Ag@SiO2 which is heteronuclear radioatice isotope of core-shell
structure prepared at Example 1 according to the present invention;
and
[0039] FIG. 18 is a result of NAA measurement of Au--Ag@SiO2 which
is heteronuclear radioisotope of core-shell structure prepared at
Example 1 according to the present invention.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0040] Embodiments of the present invention will be explained in
detail below.
[0041] According to an embodiment, heteronuclear radioisotope
nanoparticle of core-shell structure is provided, in which core of
two different types of radioisotopes is coated with SiO.sub.2.
[0042] In one embodiment, the two different types of radioisotopes
may include one selected from the radioisotopes including
.sup.198Au, .sup.63Ni, .sup.110mAg, .sup.64Cu,
.sup.60Co,.sup.192Ir, .sup.103Pd. In a preferred embodiment, the
cores of the Heteronuclear radioisotope nanoparticle may use a
combination of .sup.198Au and any particle selected from the rest
of the group excluding .sup.198Au, but not limited thereto.
[0043] In one embodiment, a method for preparing Heteronuclear
radioisotope nanoparticle of core-shell structure is provided,
which may include:
[0044] (step 1) preparing core of the heteronuclear nanoparticle by
dispersing two different types of atoms selected from a group
consisting of Au, Ni, Ag, Cu, Co, Ir and Pd in water, and
stabilizing the result with colloid stabilizer;
[0045] (step 2) preparing nanoparticle with core-shell structure by
coating the nanoparticle core prepared at step 1 with SiO.sub.2
repeatedly for several times;
[0046] (step 3) removing the colloid stabilizer remaining in the
core-shell structure prepared at step 2 by calcining the prepared
nanoparticle; and
[0047] (step 4) activating the nanoparticle within the cores by
irradiating neutron onto the nanoparticle with the core-shell
structure prepared at step 3.
[0048] The respective steps of the method for preparing
Heteronuclear radioisotope nanoparticle of core-shell structure
according to the present invention will be explained in greater
detail below.
[0049] Step 1: Preparation of core of heteronuclear
nanoparticle
[0050] In one embodiment, step 1 relates to preparing core of the
heteronucler nanoparticle by dispersing two difference types of
particles in water and stabilizing the result with colloid
stabilizer.
[0051] At step 1, the two different types of raw material for
nanoparticle may be selected from Au, Ni, Ag, Cu, Co, Ir or Pd. The
raw material may be used in purified form, or used along with all
the compounds contained therein.
[0052] At step 1, efficiency of dispersion may be enhanced by use
of colloid stabilizer which prevents agglomeration among
nanoparticles dispersed in water and provides stabilization
effect.
[0053] Any stabilizer may be used as the colloid stabilizer, as
long as the stabilizer is capable of blocking aggregation among the
colloid particles and enhancing dispersion efficiency to thus
provide stabilization of the particle, but in one preferred
embodiment, polyvinylpyrrolidone may be used.
[0054] In one embodiment, step 1 may additionally include a step
for removing oxygen present in the fluid, by performing N.sub.2
purging to prevent oxidation of the matters constituting the fluid
for reaction which contains the two different types of
elements.
[0055] Further, step 1 may enhance stabilization effect of the
heteronuclear nanoparticle by use of colloid stabilizer such as
polyvinylpyrrolidone, by irradiating gamma radiation onto the
colloid fluid. Time and dose of irradiating gamma radiation may be
adjusted appropriately depending on need and according to the raw
material of the core.
[0056] Step 2: Preparation of heteronuclear nanoparticle with
core-shell structure
[0057] Next, in step 2, nanoparticle with core-shell structure is
prepared by coating the nanoparticle core prepared at step 1 with
SiO.sub.2 repeatedly for several times.
[0058] Accordingly, as SiO.sub.2 is coated on the nanoparticle core
prepared at step 1, the nanoparticle with core-shell structure in
which core of two different types of elementals is covered by
SiO.sub.2 shell, is prepared.
[0059] To be specific, a certain amount of colloid fluid in which
heteronuclear nanoparticle core are dispersed and which is
stabilized with colloid stabilizer in step 1 may be prepared, mixed
with a solvent such as isopropanol and added with a small amount of
ammonia solution. A material to provide SiO.sub.2 as a shell may
then be added to coat around the core. The material to provide
SiO.sub.2 may include, for example, tetraethoxy orthosilicate
(TEOS). The thickness of the shell may be adjusted by repeatedly
adding TEOS for several times.
[0060] Step 3: Removal of colloid stabilizer
[0061] In step 3, colloid stabilizer is removed from the
heteronuclear nanoparticle of core-shell structure which is
prepared in step 2.
[0062] In step 3, the colloid stabilizer may be removed by
calcining under nitrogen flow. The calcination temperature may be
adjusted in accordance with the type of the colloid stabilizer
used. By way of example, if polyvinylpyrrolidone is used as the
colloid stabilizer, the calcination temperature may preferably be
500-600.degree. C.
[0063] The nanoparticle after the calcining is in powder form from
which stabilizer is removed. As explained above, the remaining
colloid stabilizer is removed to ensure quality and quantity of the
component that can be obtained in the radiation detection emitted
from the radioisotope, because if the colloid stabilizer is left in
the heteronuclear nanoparticle, there is the possibility that the
colloid stabilizer can also be activated when the nanoparticle is
activated in the following step.
[0064] Step 4: Preparation of Heteronuclear radioisotope
nanoparticle of core-shell structure
[0065] Next, in step 4, the nanoparticle of core-shell structure
prepared in step 3 is activated.
[0066] The activation may be performed by irradiating neutron in
the nuclear reactor on the heteronuclear nanoparticle of core-shell
structure prepared in step 3.
[0067] Since the heteronuclear nanoparticle of core-shell structure
activated in step 4 according to the present invention emits
specific radiation emitted from the respective nuclides, the
nanoparticle can be used for various purposes.
[0068] Furthermore, in one embodiment, Heteronuclear radioisotope
nanoparticle of core-shell structure isprovided, which can be used
as a tracer for the purpose of detecting movement of the fluid
existing in the multi phase process driven under extreme conditions
including high temperature and/or high pressure, or used for the
purpose of evaluating the behavior of the water resource.
[0069] Unlike the homonuclear nanoparticle, the nanoparticle in one
embodiment of the present invention has different types of
heteronuclear radioisotopes as the core and thus can emit gamma ray
of different characteristics. Accordingly, it is possible to
measure the respective phrase ratios by analyzing information about
the movements of the multi phase fluid particularly existing in
high temperature and high pressure industrial processing which does
not easily permit access. Further, it is also possible to calculate
the volume ratio based on the information about the phase ratio of
the multi phase fluid.
[0070] In general, radiation attenuation coefficient of a matter
changes in accordance with the radiation energy. If two types of
radiation sources that emit two different gamma energies are used,
it is possible to obtain the phase ratio of the mixture. The fluid
compound rate (.alpha..sub.i) according to two types of gamma ray
energy absorption can be calculated by:
I m ( e ) = I .upsilon. ( e ) exp [ - i = 1 3 .alpha. i .mu. i ( e
) d ] [ Mathematical formula 1 ] ##EQU00001##
[0071] where, I.sub.u(e) denotes initial value of the system which
indicates the radiation amount detected in a state where the system
is empty. .mu..sub.i denotes linear attenuation coefficient with
respect to multi phase. By way of example, if two gamma ray
energies e.sub.1, e.sub.2 with large differences of attenuation
coefficients are selected from the respective phases of the multi
phase fluid consisting of water, oil and gas, two formulae can be
obtained. Since 1 is the sum of total phase ratios of the mixture,
the third mathematical formula can be obtained accordingly.
[0072] If the heteronuclear radioisotope nanoparticle of core-shell
structure prepared according to an embodiment of the present
invention is used as a tracer for the movement of multi phase
fluid, since the cores comprising two different types of
radioisotopes, two gamma ray energies, i.e., .sup.198Au(e.sub.1)
and .sup.110mAg(e.sub.2) are selected to obtain two mathematical
formulae. The third mathematical formula can be obtained based on
the fact that the sum of the total phase ratios of the mixture is
1.
[0073] Referring to the above examples, the three formulae obtained
through mathematical formula 1 by selecting two gamma ray energies
e.sub.1 and e.sub.2 from the multi phase fluid consisting of water,
oil and gas may be expressed as follows:
[ R w ( e 1 ) R o ( e 1 ) R g ( e 1 ) R w ( e 2 ) R o ( e 2 ) R g (
e 2 ) 1 1 1 ] [ .alpha. w .alpha. o .alpha. g ] = [ R m ( e 1 ) R m
( e 2 ) 1 ] [ Mathematical formula 2 ] ##EQU00002##
[0074] where, R.sub.W, R.sub.0, R.sub.g and R.sub.m are log values
of detected radiation amounts with respect to water, oil, gas and
mixture by the two gamma ray energies e.sub.1 and e.sub.2,
respectively. R.sub.W, R.sub.0, R.sub.g which are necessary for the
calculation, are obtained by the correction process in which the
system is filled with the corresponding phases to 100% and
measured. In actual measurement test, ratios .alpha..sub.W,
.alpha..sub.o, .alpha..sub.g of the respective phases may be
obtained by obtaining gamma ray energies R.sub.m(e.sub.1) and
R.sub.m(e.sub.2) and applying these to mathematical formula 2.
[0075] By applying the above-explained example, it is possible to
measure the gamma ray energy under the following condition, to
obtain information about the phase ratio of the movement of the
multi phase fluid by using heteronuclear radioisotope nanoparticle
of core-shell structure. First, detected radiation amount
I.sub.u(e) is measured as the initial value in the empty system.
Then, water phase ratio .alpha..sub.w, oil phase ratio
.alpha..sub.O, and gas phase ratio .alpha..sub.g in the mixture
state are obtained by applying the log values of the measured
values of .sup.198Au and .sup.110mAg gamma ray energies emitted
from: system of 100% water, system of 100% oil, and system of 100%
gas to mathematical formula 2. From the above, it is possible to
obtain volume ratios of the respective fluids constructing multi
phase fluid.
[0076] Hereinbelow, an embodiment of the present invention will be
explained in greater detail. However, an embodiment is not limited
to specific examples only.
EXAMPLE 1
Step 1. Preparation of Heteronuclear Nanparticle Core by Radiation
Reduction
[0077] 0.19 mmol of HAuCl.sub.43H.sub.2O (0.078 g) and
AgNO.sub.3(0.033 g) were dispersed in tertiary distilled water (376
ml) so that Au and Ag were at 1:1 mole ratio. To the fluid in which
HAuCl.sub.43H.sub.2O and AgNO.sub.3 were dispersed,
polyvinylpyrrolidone (1 g) as colloid stabilizer and isopropanol
(24 ml) were added and mixed. The reacted fluid underwent nitrogen
purging to remove oxygen existing in the solution, and
.sup.60Co-.gamma. was irradiated for 3 hr, in a manner in which the
total dose of radiation was 30 kGy. The reacted fluid was yellow
before reaction, and turned into purple after irradiation so that
Au--Ag nanoparticle, which was stabilized with
polyvinylpyrrolidone, can be prepared.
Step 2. Preparation of Heteronuclear Nanonparticle with Core-Shell
Structure by Sol-Gel Reaction
[0078] Colloid fluid (4 ml), in which the Au--Ag nanoparticle core
stabilized with polyvinylpyroolidone and prepared in step 1, was
mixed with isopropanol (20 ml), 30 wt. % ammonia solution (0.5 ml)
was added to the reaction vessel, and tetraetoxy orthosilicate
(TEOS) (10 mmol) was added, and left to react for 2 hr at room
temperature. As a result, nanoparticle (Au--Ag@SiO) having Au--Ag
core and SiO.sub.2 shell was prepared.
Step 3. Removal of Colloid Stabilizer
[0079] Polybvinylpyrrolidon, which is colloid stabilizer, was
completely removed as the nanoparticle (Au--Ag@SiO.sub.2) prepared
in step 2 was calcined at 500.degree. C. under nitrogen flow.
Step 4. Preparation of Heteronuclear Radioisotope Nanoparticle of
Core-Shell Structure
[0080] Radioisotope nanoparticle Au--Ag@SiO.sub.2(20 mg) having
Au--Ag core and SiO.sub.2 shell was prepared, by irradiating
neutrons to the nanoparticle (.sup.198Au-.sup.110mAg@SiO.sub.2)
prepared in step 3 in the nuclear reactor (Hanaro, neutron
irradiation: 2.8.times.10.sup.13/cd s) designed for research at the
Korea Atomic Energy Research Institute.
Example 2
[0081] The radioisotope nanoparticle having Au--Ni core and
SiO.sub.2 shell was prepared in the same manner as that in Example
1, except that Ni instead of Ag was used as the nuclides of the
nanoparticle core and 0.19 mmol of HAuCl.sub.43H.sub.2O (0.078 g)
and Ni(NO.sub.3).sub.26H.sub.2O (0.055 g) were used to 1:1 mole
ratio.
Example 3
[0082] The radioisotope nanoparticle having Au--Co core and
SiO.sub.2 shell was prepared in the same manner as that in Example
1, except that Co instead of Ag was used as the nuclides of the
nanoparticle core and 0.19 mmol of HAuCl.sub.43H.sub.2O (0.078 g)
and CoCl.sub.26H.sub.2O (0.045 g) were used to 1:1 mole ratio.
Example 4
[0083] The radioisotope nanoparticles having Au--Cu cores and
SiO.sub.2 shells were prepared in the same manner as that in
Example 1, except that Cu instead of Ag was used as the nuclides of
the nanoparticle cores and 0.19 mmol of HAuCl.sub.43H.sub.2O (0.078
g) and CuCl.sub.22H.sub.2O (0.032 g) were used to 1:1 mole
ratio.
Example 5
[0084] The radioisotope nanoparticle having Au--Ir core and
SiO.sub.2 shell was prepared in the same manner as that in Example
1, except that Ir instead of Ag was used as the nuclides of the
nanoparticle core and 0.19 mmol of HAuCl.sub.43H.sub.2O (0.078 g)
and IrCl.sub.4.xH.sub.2O (0.063 g) were used to 1:1 mole ratio.
Analysis:
[0085] 1. Transmission Electron Microscopy (TEM)
[0086] Nanoparticles prepared according to Examples 1 to 5 of the
present invention were measured with TEM (JEOL, JEM-2010F, Japan),
and the results are provided on FIGS. 2 to 7. Referring to FIG. 3,
Au--Ag heteronuclear nanoparticle of Example 1 prepared according
to an embodiment of the present invention include approximately 40
nm core and approximately 30 nm shell (FIG. 2: Example 1, FIG. 3:
Example 1, FIG. 4: Example 2, FIG. 5: Example 3, FIG. 6: Example 4,
FIG. 7: Example 5). The results indicated that the core-shell
nanoparticle was prepared successfully.
[0087] 2. Nanoparticle component analysis using Energy Dispersive
Spectroscopy (EDS)
[0088] Core or core-shell nanoparticles prepared according to
Examples 1 to 5 were measured using EDS (JEM-2010F, Japan), and the
results are provided on FIGS. 8 to 13 (FIG. 8: Example 1, FIG. 9:
Example 1, FIG. 10: Example 2, FIG. 11: Example 3, FIG. 12: Example
4, FIG. 13: Example 5). The results indicated that the core-shell
nanoparticle was prepared successfully.
[0089] 3. Nanoparticle Analysis using Grain Size Measurement
(ELS)
[0090] Core or core-shell nanoparticles prepared according to
Examples 1 and 3 were measured using ELS (ELS-8000, Otsuka Co.,
Japan), and the results are provided on FIGS. 14 to 16 (FIG. 14:
Example 1, FIG. 15: Example 1, FIG. 16: Example 3). The results
indicated that the core-shell nanoparticle was prepared
successfully.
[0091] 4. Core-Shell Nanoparticle Analysis using UV-Visible
Spectrophotometer
[0092] Core-shell nanoparticle prepared according to Example 1 was
measured using UV-Vis Spectrophotometer (Shimadzu UV-3101PC digital
spectrophotometer, Kyoto, Japan), and the results are provided on
FIG. 17. The results indicated that the core-shell nanoparticle was
prepared successfully.
[0093] 5. Core-Shell Nanoparticle Analysis using Neutron Activation
Analysis (NAA)
[0094] Core-shell nanoparticle prepared according to Example 1 was
measured using NAA (HPGe detector, EG&G Ortec, 25% relative
efficiency, FWHM 1.85 keV at 1332 keV of .sup.60Co), and the
results are provided on FIG. 18. The results confirmed that no
radioactive nuclides were generated except for Au and Ag by the
neutron irradiation.
[0095] The foregoing exemplary embodiments and advantages are
merely exemplary and are not to be construed as limiting the
present invention. The present teaching can be readily applied to
other types of apparatuses. Also, the description of the exemplary
embodiments of the present inventive concept is intended to be
illustrative, and not to limit the scope of the claims, and many
alternatives, modifications, and variations will be apparent to
those skilled in the art.
* * * * *