High Emissivity Ceramic Composite for Nonthermal Far Infrared Radiation

Abstract

This invention relates to a ceramic composite that may be used for various purposes including for assembly into a therapeutic device for treating a human or animal body with irradiation of nonthermal far infrared (FIR) radiation. More specifically, while all FIR-related prior art is only radiating broadband blackbody thermal radiation, said ceramic composite can emit not only the usual blackbody thermal radiation but also the inventive nonthermal FIR-photon radiation in the 3 - 16 .Math.m wavelength spectrum. As a result, the overall measurable radiation in 8 - 14 .Math.m wavelength range from said ceramic composite has an approximated blackbody temperature that is at least 1° C. higher than the actual temperature of said ceramic composite, signifying an effective emissivity greater than 1.0, while 1.0 emissivity is a theoretical limit assigned to an ideal black body and thus unsurpassable. It is an outcome of adding the 3 - 16 .Math.m band of nonthermal FIR-photon radiation to the continuous 4 - 1,000 .Math.m band of blackbody thermal radiation.

Claims

1. A method of producing a non-thermal far infrared radiation (FIR) emitting ceramic composite comprising: a) heating a powdered material at a heating rate to reach a sintering temperature; b) sintering said powdered material at the sintering temperature for a sintering time; c) cooling said powdered material at a cooling rate to form a ceramic composite; wherein steps a) through c) produce at least one phase transformation such that the ceramic composite comprises at least one far infrared luminescence center of at least one octahedral complex formed by a transition metal ion surrounded by six oxygen anions or one tetrahedral complex formed by a transition metal ion surrounded by four oxygen anions; and wherein said anions generate an electrostatic crystal field around said complexes; and resulting in said ceramic composite emitting non-thermal far infrared radiation in the 3 -16 .Math.m wavelength spectrum, wherein the overall measurable radiation over the 8 - 14 .Math.m wavelength range is approximated as blackbody radiation at a temperature at least 1° C. higher than the actual body temperature of said ceramic composite, signifying an effective emissivity greater than 1.0.

2. A method of claim 1: wherein said material is created by mixing a solvent of about 10% or more by weight of a first oxide; and a solute comprising about 3% or more by weight of a second oxide and about 3% to about 20% by weight of a third oxide.

3. A method of claim 1, wherein: the first oxide comprises one or more of the following: silicon oxide and aluminum oxide.

4. A method of claim 1, wherein: the second oxide comprises one or more of the following: chromium oxide and iron oxide.

5. The method of claim 1, wherein: the third oxide comprises one or more of the following: zirconium oxide, titanium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, niobium oxide, lithium oxide, sodium oxide, potassium oxide, magnesium oxide, and calcium oxide.

6. The method of claim 1, wherein: the heating rate is between about 5 degrees and about 10° C. per minute.

7. The method of claim 1, wherein: the sintering temperature is between about 1,000 and 1,600° C.

8. The method of claim 1, wherein: the sintering temperature is between about 50% and about 75% of the melting temperature of the solvent.

9. The method of claim 1, wherein: the sintering time is at least two hours.

10. A composition of a non-thermal far infrared radiation emitting ceramic composite comprising: a solvent of about 10% or more by weight of a first oxide; and a solute comprising about 3% or more by weight of a second oxide and about 3% to about 20% by weight of a third oxide.

11. The composition of claim 10, wherein: the first oxide comprises one or more of the following: silicon oxide and aluminum oxide.

12. The composition of claim 10, wherein: the second oxide comprises one or more of the following: chromium oxide and iron oxide.

13. The composition of claim 10, wherein: the third oxide comprises one or more of the following: zirconium oxide, titanium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, niobium oxide, lithium oxide, sodium oxide, potassium oxide, magnesium oxide, and calcium oxide.

14. A therapeutic device for treating a human or animal body comprising: a ceramic module capable of emitting blackbody thermal radiation and stimulated far infrared photon radiation with an effective emissivity greater than about 1.0 affixed with a flexible means for attaching the module to a body part to be treated.

15. The therapeutic device of claim 14, wherein: the ceramic module emits blackbody thermal radiation in wavelengths of about 4 to about 1,000 .Math.m and stimulated FIR-photon radiation for wavelengths between about 3 to about 16 .Math.m.

16. The therapeutic device of claim 14, wherein: the ceramic module comprises three oxides.

17. The therapeutic device of claim 16, wherein: a first oxide comprises one or more of the following: silicon oxide and aluminum oxide.

18. The therapeutic device of claim 16, wherein: a second oxide comprises one or more of the following: chromium oxide and iron oxide.

19. The therapeutic device of claim 16, wherein: a third oxide comprises one or more of the following: zirconium oxide, titanium oxide, manganese oxide, iron oxide, cobalt oxide, nickel oxide, copper oxide, zinc oxide, niobium oxide, lithium oxide, sodium oxide, potassium oxide, magnesium oxide, and calcium oxide.

20. The therapeutic device of claim 14, wherein: the ceramic module includes at least one FIR luminescence center of at least one octahedral complex formed by a transition metal ion surrounded by six oxygen anions, said anions generating an electrostatic crystal field around said complexes; and resulting in said ceramic composite having a persistent phonons-activated FIR-photon emission mechanism.

21. The therapeutic device of claim 14, wherein: the ceramic module includes at least one FIR luminescence center of at least one tetrahedral complex formed by a transition metal ion surrounded by four oxygen anions, said anions generating an electrostatic crystal field around said complexes; and resulting in said ceramic composite having a persistent phonons-activated FIR-photon emission mechanism.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0106] FIG. 1 is a perspective view of a first embodiment of the present invention showing a ceramic composite in the shape of a sphere.

[0107] FIG. 2 is a perspective view of a second embodiment of the present invention showing a ceramic composite in the shape of a circular plate.

[0108] FIG. 3 is a perspective view of a third embodiment of the present invention showing a ceramic composite in the shape of a rectangular plate.

[0109] FIG. 4 is a perspective view of a fourth embodiment of the present invention showing a ceramic composite in the shape of a partial cylinder.

[0110] FIG. 5 is a top perspective view of a fifth embodiment of the present invention showing multiple ceramic composites are mounted on a flexible substrate for attaching to a body part to be treated, wherein each of ceramic composite has a concave surface facing the body.

[0111] FIG. 6 is a bottom perspective view of the embodiment of FIG. 5, showing the pockets containing the concave ceramic composites.

[0112] FIG. 7 is a perspective view of a seventh embodiment of the invention, showing an array of IR-emitting elements embedded within a substrate and disposed within an attachment means.

[0113] FIG. 8 is a perspective view of an eighth embodiment of the invention, showing an array of IR-emitting elements embedded within a substrate and disposed within an attachment means.

[0114] FIG. 9 is a perspective view of an eighth embodiment of the invention, showing an array of IR-emitting elements embedded within a substrate and disposed within an attachment means.

[0115] FIG. 10 is a perspective view of an eighth embodiment of the invention, showing an array of IR-emitting elements embedded within a substrate and disposed within an attachment means.

[0116] FIG. 11 is a perspective view of an eighth embodiment of the invention, showing an array of IR-emitting elements embedded within a substrate and disposed within an attachment means.

TABLE-US-00001 Reference Numerals in Drawings 11 ceramic composite 21, 23, 31, 41, 51, 61 substrate 22, 28, 34, 44, 54, 64 pockets 24, 32, 42, 52, 62 encasement 25, 30, 40, 50 straps 28, 34, 44, 54, 64 pockets 29, 36, 46, 56, 66 holes

DETAILED DESRIPTION OF THE INVENTION

[0117] The invention is a ceramic composite that can emit not only the natural blackbody thermal radiation in 4 - 1,000 .Math.m wavelength spectrum but also the innovative nonthermal FIR-photon radiation in the specified 3 - 16 .Math.m wavelength band. The ceramic composite features an inventive “persistent phonons-activated FIR-photon emission mechanism” that absorbs ambient thermal radiation to stimulate emissions of FIR-photons in the 3 - 16 .Math.m wavelength range persistently.

[0118] The persistent phonons-activated FIR-photon emission mechanism (or “persistent FIR-luminescence” mechanism) embraces numerous FIR-luminescence centers that are founded on transition-metal (TM) ion coordination complexes with either octahedral or tetrahedral structures. The present invention will only focus on octahedral structures for the sake of easier design, higher efficiency, and more predictable results. A similar composite may be fabricated with tetrahedral structures by following the teachings of present invention, which will be pointed out later.

[0119] The building blocks of FIR-luminescence centers are [CrO.sub.6].sup.3+, [FeO.sub.6].sup.3+, or the like, which consists of a transition metal ion, such as chromium-III (Cr.sup.3+) or iron-III (Fe.sup.3+), surrounded by six oxygen anions, forming an octahedral coordination complex. By design, the TM-ion is placed in a weak electrostatic crystal field formed by the anions (or oxoanions) in the host lattice together with the surrounding doped cations. In this arrangement, the energy δ.sub.2 of crystal field splitting can be devised by prearranged type and number of doped cations to be around 100 - 315 meV, based on CFT modeling. This corresponds to a wavelength spectrum in 4 - 12 .Math.m, with a projected photoluminescence profile covering the specified 3 - 16 .Math.m wavelength range.

[0120] Accordingly, the ceramic composite comprises a solid solution, with the amount of solvent > 50 wt.% and solute < 50 wt.%. Said solvent consists of at least 10 wt.% aluminum oxide (Al.sub.2O.sub.3) that helps construct the required octahedral crystalline framework in host lattice for the persistent FIR-photon emission mechanism. The rest wt.% of solvent may include silicon oxide (SiO.sub.2) for building a more stable host lattice that contains aluminosilicate (Al.sub.2SiO.sub.5). Besides, its oxoanions (SiO.sub.4.sup.4-, AlSiO.sub.4.sup.-) also provide a viable approach for fine-tuning the crystal field splitting.

[0121] In implementation, the solvent may make up to 50 - 80 wt.% of the solution and consists of about 10 - 40 wt.% Al.sub.2O.sub.3 and 10 - 40 wt.% SiO.sub.2. To give an example, 20 wt.% aluminum oxide and 40 wt.% silicon oxide may be used to build a stable host lattice that holds a layered structure with interlocked tetrahedrons and octahedrons.

[0122] The present invention uses Cr and Fe respectively in separate cases for substituting Al in the host lattice to demonstrate the concept. The transition metal ions, Cr.sup.3+ or Fe.sup.3+, are expected to replace Al.sup.3+ ions in the octahedral sites of host lattice during sintering.

[0123] Typically, the solute may contain two parts. The first part, mainly for constructing the FIR-luminescence centers, shall comprise at least 3 wt.% chromium oxide (Cr.sub.2O.sub.3) and/or iron oxide (Fe.sub.2O.sub.3). The quantity may be in the range of 3 - 40 wt.%, though 10 - 20 wt.% is preferred.

[0124] The second part of solute, for fine-tuning the crystal field splitting, may include 3 - 20 wt.% oxides of other transition metals such as zirconium (Zr), titanium (Ti), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), or niobium (Nb), and alkali or alkaline earth metals such as lithium (Li), sodium (Na), potassium (K), magnesium (Mg), or Calcium (Ca). The cations from transition metal or metal elements are utilized to manipulate the electrostatic crystal field, by interstitially fitting into the space between solvent particles in the host lattice during sintering.

[0125] It is worthwhile noting here that among aforesaid transition metals, the elements Zr, Ti, Co, and Ni may be managed to substitute Si in the [SiO.sub.4].sup.4- tetrahedral structures of the host lattice, under related sintering conditions. In this case, they may act as additional FIR-luminescence centers. Or, themselves may be used alone to produce a ceramic composite similar to the one disclosed in present invention. It will be obvious to anyone skilled in the art to make such a composite by following the teachings of present invention, but simply changing the process parameters associated with the selected materials.

[0126] n one embodiment, the solid solution of present invention includes 70 wt.% of solvent and 30 wt.% solute. The solvent consists of 45 wt.% silicon oxide and 25 wt.% aluminum oxide. The solute consists of 25 wt.% transition metal oxides, including 5% chromium oxide and 15% iron oxide for FIR-emitting purpose, and with the rest 5 wt.% of minor transition oxides, such as zirconium oxide, titanium oxide, and zinc oxide, as cations-dopants. The second part of solute consist of up to 5 wt.% in total calcium oxide, potassium oxide and magnesium oxide, for cation-doping.

[0127] After appropriate oxides being selected, the mixture of these oxides can be processed into a shaped article or powders form for practical uses, such as in the therapeutic devices. The process involves mixing all constituent oxides with bonding agents and stabilizers, followed by grinding, drying, forming, green machining, and sintering. The consequent FIR radiation spectrum and its spectral strength depend on the resultant crystalline structure, which may be influenced by many factors, including sintering temperature, length of sintering time, and a course with specified steps and correlated heating/cooling rates.

[0128] The powder mixture of the solid solution system will be heated to a temperature that is in the range of 0.5 - 0.75 of the melting temperature. For Al.sub.2O.sub.3 with a melting temperature of 2,073° C., the sintering temperature is commonly in about 1,000 - 1,600° C. During the solid-state sintering process, the powder does not melt. Instead, the joining together of the particles and the reduction in the porosity (densification) of the body occur by atomic diffusion in the solid states.

[0129] The simplest system involves the reaction between two solid phases, A and B, to produce a product C. For example, when both aluminum oxide and silicon oxide are used as solvent, the formation of the product, aluminosilicate (Al.sub.2SiO.sub.5) for the host lattice, at a temperature above 1,100° C. can be presented as:

##STR00001##

For the meantime during the course of sintering, chromium cations (Cr.sup.3+) or iron cations (Fe.sup.3+) may take over the octahedral sites of aluminum cations (Al.sup.3+) in aluminosilicate lattice and form FIR-luminescence centers, denoted by [Al.sub.2SiO.sub.5—Cr.sup.3+] or [Al.sub.2SiO.sub.5—Fe.sup.3+], respectively.

[0130] The reaction mechanism involves counter diffusion of the cations (Al.sup.3+ vs. Cr.sup.3+ or Fe.sup.3+). The cations migrate in opposite directions with the oxygen ions remaining essentially stationary. This mechanism is the most likely mechanism, in which the cation flux is coupled to maintain electroneutrality.

[0131] When the rate of product formation is controlled by diffusion through the product C layer, the product thickness y is observed to follow a parabolic growth law:

[00003]$y^2=Kt$

where t is the length of sintering time and K is the rate constant that obeys the Arrhenius relation.

[0132] The reaction is said to be 100% (complete), when y = r.sub.a + r.sub.b, r.sub.a and r.sub.b being the radius of reactants A and B, respectively. It means that the reaction is diffusion controlled and in practice, the diffusion coefficients of such cations differ widely.

[0133] The reaction rate (K) will decrease with temperature according to the Arrhenius relation. The sintering time required for completing the reaction increases with an increase in the particle size of reactants (r.sub.a, r.sub.b) because the diffusion distance (r.sub.a + r.sub.b) will increase. Thus, the powder characteristics of greatest interest would be the size, size distribution, shape, degree of agglomeration, chemical composition, and purity.

[0134] Generally, larger particles (> 10 .Math.m) need a higher temperature and longer time to react because of the diffusion mechanism during sintering. A continuing trend is toward the preparation of fine powders, in particular very fine powders with a particle size in 50 - 100 nm (often referred to as nanoscale powders). However, as the size decreases below 1 .Math.m, the particles exhibit a greater tendency to interact, leading to the formation of agglomerates so that it may require proper control.

[0135] Besides, the kinetics of grain growth is also influenced by the grain size distribution. If the distribution is large, the pressure difference between the smaller and larger grains is very high, and thus the growth of larger grains at the expense of smaller ones is much faster than where the distribution is narrow. So, a narrow distribution of powder sizes, for examples, 50 - 100 nm for nano-powders or 1 - 10 .Math.m for micron-particles is preferred. Nonetheless, the optimal particle size and size distribution for practical implementation would be 0.1 - 1 .Math.m.

[0136] Normally, the homogeneity of mixing is one of the most critical parameters. It influences the diffusion distance between reactants and the relative number of contacts between the reactant particles, and thus to produce a homogeneous product. Incomplete reactions, especially in poorly mixed powders, produce undesirable phases.

[0137] Higher temperature usually increases the rate of sintering mechanisms and reduces the time required for accomplishing the diffusion reactions. Higher temperature can accelerate volume diffusion, compared to interfacial diffusion. Since grain growth is often controlled by surface diffusion, while densification is controlled by volume diffusion or grain boundary diffusion, higher temperature often leads to higher densification, compared to grain growth. Given that interfacial diffusion mechanisms are preferred to volume diffusion, it is necessary to choose an optimal sintering temperature. Additionally, to allow proper phase transformation of the participating elements into the designed polycrystalline structure, a heating cycle that is divided into several steps with correlated heating/cooling rate is required.

[0138] That said, in at least one embodiment of the present invention, a course of three-steps, with a heating rate of 5 - 10° C./min to reach a temperature at 1,200° C. and sintering the solution for at least 2 hours, is used to allow necessary phase transformations. Afterwards, a controlled cooling is also needed to secure the phases in the designed polycrystalline structure.

[0139] One key aspect in present invention is to create FIR-luminescence centers with octahedral complexes of [CrO.sub.6].sup.3+, [FeO.sub.6].sup.3+, or the like. And, the other aspect is to generate an appropriate electrostatic crystal field that surrounds the complex. If everything goes well with the design, the resultant ceramic composite will be capable of emitting nonthermal FIR-photon radiation in the specific 3 - 16 .Math.m wavelength band. Said ceramic composite can be explicitly demonstrated to have an effective emissivity greater than 1.0 by using a commercially available sensor in the 8 -14 .Math.m wavelength range.

[0140] Despite above guidelines, the solid-state reaction in powder systems depends on several parameters, such as the chemical nature of the reactants and the product, the size, the size distribution and shape of the particles, the relative sizes of the reactant particles in the mixture, the uniformity of the mixing, the reaction atmosphere, the temperature, the heating/cooling rate and the time, and so forth. Thus, the result is difficult to predict with a simplified theoretical modeling.

[0141] In practice, numerous experiments have to be performed in order to observe the influence of synthesis parameters on polycrystalline structure and material properties. Various experimental samples had been tried out with different sintering temperatures and heating courses before a synthesis process of the ceramic composite of present invention could be finalized. The fabrication process is surely nontrivial. Yet, any one skilled in ceramic processing should be able to figure out his own synthesis parameters experimentally by following the teaching described herein.

[0142] With carefully chosen composition and synthesis parameters, the subsequent ceramic composite would produce a blend of crystalline and amorphous regions. Each crystalline region allows electron transitions within the [CrO.sub.6].sup.3+or [FeO.sub.6].sup.3+ octahedral structures that functions as a dipole, governed by the inventive persistent phonons-activated FIR-photon emission mechanism. The stimulated FIR-photons in the 3 - 16 .Math.m wavelength spectrum are so generated.

[0143] The ceramic composite of present invention, prepared as disclosed above, has an overall FIR radiation, including both the blackbody-like thermal radiation and the stimulated FIR-photon radiation, that can be approximated as a blackbody radiation at a temperature at least 1 °K (or 1° C.) higher than the actual body temperature of said ceramic composite. It signifies an effective emissivity greater than 1.0 (ε > 1.0).

[0144] FIGS. 1-3 show three separate embodiments of the present invention of varying shapes: in FIG. 1, the ceramic composite 11 is shaped as a sphere, in FIG. 2, the ceramic composite 11 is shaped as a circular plate, and in FIG. 3, the ceramic composite 11 is shaped as a rectangular plate. It can also be prepared in form of powders, though the bulk-form has at least three times higher radiation efficiency than the powder-form with the same mass.

[0145] The ceramic composite(s) 11 of the present invention may be formed into various shapes and sizes, depending upon the particular applications. In at least one embodiment, the ceramic composites may be circular in shape, and may be a 2 - 50 mm diameter circle with a thickness of 1-10 mm. In another embodiment, the ceramic composites may be rectangular, having dimensions of a 2 by 3 mm rectangle to a 40 by 50 mm rectangle, with a thickness of 1 - 10 mm. Rectangular and circular shaped ceramics are generally easier to fabricate than other shapes.

[0146] Nonetheless, it may be advantageous to form the ceramic composite 11 with a concave shape. It is anticipated that a concave surface will help focus the rays of radiation emitted by the ceramic composite in a region or point at a distance from the surface of the ceramic composite. The concave surface may take a variety of shapes, such as hemispherical, bowl-shaped, or a partial cylinder. FIG. 4 shows an embodiment of the present invention, in which ceramic composite 11 has a partial cylinder shape.

[0147] FIG. 5 shows a preferred embodiment of the present invention for therapeutic applications, in which multiple ceramic composites 11 are embedded in a substrate 21, which may be made from silicone, or similar materials. The substrate 21 is a substantially flat sheet that includes a number of pockets 22, which are curved protrusions dimensioned to contain ceramic composites 11. FIG. 6 illustrates the underside of substrate 21, which faces away from the body part being treated. In this embodiment, all pockets 22 have the same dimension because all ceramic composites 11 have the same dimensions. In other embodiments, however, pockets 22 may have different sizes or shapes tailored to specific applications or arrangements of variable ceramic composites 11.

[0148] Also, the ceramic composite 11 in FIG. 5 has a partial cylindrical shape. The partial-cylindrical shaped ceramic composite is arranged to have the concave surface facing toward the body part to be treated. This arrangement helps to focus FIR radiation at about one (1) inch above the surface of the device. When the device is wrapped closely around the body during use, the radiation will be focused to a depth of about one inch into the body tissue, and thus significantly enhance the radiation effect in the body.

[0149] FIG. 7 shows another embodiment of the invention in which a substrate 23 is enclosed within an attachment means. Preferably, the attachment means comprises an encasement 24 and straps 25 attached to both ends of the encasement 24. In the embodiment shown in FIG. 7, the encasement 24 includes holes 29 formed in one side. The holes 29 are dimensioned and positioned to allow pockets 28 of the substrate 23 to partially protrude outside the encasement 24 such that the encasement 24 is substantially flat on the side facing the user. However, other configurations are also within the scope of the invention, such as encasements lacking holes. This embodiment may be adapted to fit around a user’s waist, such that the pockets 28 generally target FIR radiation around the user’s lower back.

[0150] FIG. 8 shows another embodiment of the invention in which a substrate 31 is enclosed within an attachment means. Preferably, the attachment means comprises an encasement 32 and straps 30 attached to both ends of the encasement 32. In the embodiment shown in FIG. 8, the encasement 32 includes holes 36 formed in one side. The holes 36 are dimensioned and positioned to allow pockets 34 of the substrate 31 to partially protrude outside the encasement 32 such that the encasement 32 is substantially flat on against the user’s body. However, other configurations are also within the scope of the invention, such as encasements lacking holes. This embodiment may be adapted to fit around a user’s shoulder, such that the pockets 34 generally target FIR radiation around the user’s shoulder.

[0151] FIG. 9 shows another embodiment of the invention in which a substrate 41 is enclosed within an attachment means. Preferably, the attachment means comprises an encasement 42 and straps 40 attached to both ends of the encasement 42. In the embodiment shown in FIG. 9, the encasement 42 includes holes 46 formed in one side. The holes 46 are dimensioned and positioned to allow pockets 44 of the substrate 41 to partially protrude outside the encasement 42 such that the encasement 42 is substantially flat on the side facing the user. However, other configurations are also within the scope of the invention, such as encasements lacking holes. This embodiment may be adapted to fit around a user’s knee, such that the pockets 44 generally target FIR radiation around the user’s knee cap.

[0152] FIG. 10 shows another embodiment of the invention in which a substrate 51 is enclosed within an attachment means. Preferably, the attachment means comprises an encasement 52 and straps 50 attached to both ends of the encasement 52. In the embodiment shown in FIG. 10, the encasement 52 includes holes 56 formed in one side. The holes 56 are dimensioned and positioned to allow pockets 54 of the substrate 21 to partially protrude outside the encasement 52 such that the encasement 52 is substantially flat on the side facing the user. However, other configurations are also within the scope of the invention, such as encasements lacking holes. This embodiment may be adapted to fit around a user’s wrist, such that the pockets 54 generally target FIR radiation around the user’s wrist.

[0153] FIG. 11 shows another embodiment of the invention in which a substrate 61 is enclosed within an attachment means. Preferably, the attachment means comprises an encasement 62 that can separate to be installed around a user’s body part. In the embodiment shown in FIG. 11, the encasement 62 includes holes 66 formed in one side. The holes 66 are dimensioned and positioned to allow pockets 64 of the substrate 21 to partially protrude outside the encasement 62 such that the encasement 62 is substantially flat on the side facing the user and the encasement 62 wraps around a user’s body part, such as a forearm, ankle, or shin, among others. However, other configurations are also within the scope of the invention, such as encasements lacking holes. This embodiment may be adapted to fit around a user’s wrist, such that the pockets 64 generally target FIR radiation around the user’s body part.

[0154] Substrates 21, 23, 31, 41, 51, and 61 in various embodiments may be made from silicone (polydimethylsiloxane), zinc sulfide, sodium chloride, potassium bromide, or similar material.

[0155] In experiments, the ceramic composites are made into a shape of ⅓-circumference cutout of a 12-mm long cylindrical tube, with 10-mm I.D. (inner diameter) and 20-mm O.D. (outer diameter). The specific spectral luminance of the ceramic composite was measured to cover the 3 - 16 .Math.m wavelength spectrum. Furthermore, the thermal radiation that adds up blackbody-like thermal radiation to the stimulated FIR-photon radiation in the 8 - 14 .Math.m wavelength range was measured by a commercial sensor and approximated as blackbody radiation at a temperature about 3° C. higher than the actual temperature of said ceramic composite, which signifies an effective emissivity of 1.04 (ε = 1.04).

Conclusion, Ramifications, and Scope

[0156] According to the present invention, a ceramic composite features a persistent phonons-activated FIR-photon emission mechanism that is capable of simultaneously emitting blackbody thermal radiation in 4 - 1,000 .Math.m wavelength spectrum as well as the stimulated FIR-photon radiation in the 3 - 16 .Math.m wavelength band, resulting in an effective emissivity greater than 1.0. The ceramic composite may be used for various purposes, including providing an effective means to improve health conditions of a human or animal body, based on enhanced chemical reaction rates in the body by absorption of 3 - 16 .Math.m wavelength FIR-photons that leads to positive biological effects.

[0157] The invention has been described above. Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. Such variations are not to be regarded as a departure from the spirit and scope of the invention and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.