CN112315460A - Application of sulfur-nitrogen polymer in fingerprint display - Google Patents
Application of sulfur-nitrogen polymer in fingerprint display Download PDFInfo
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- CN112315460A CN112315460A CN202011219677.6A CN202011219677A CN112315460A CN 112315460 A CN112315460 A CN 112315460A CN 202011219677 A CN202011219677 A CN 202011219677A CN 112315460 A CN112315460 A CN 112315460A
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- 229920000642 polymer Polymers 0.000 title claims abstract description 38
- PFRUBEOIWWEFOL-UHFFFAOYSA-N [N].[S] Chemical compound [N].[S] PFRUBEOIWWEFOL-UHFFFAOYSA-N 0.000 title claims abstract description 32
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 25
- 229910052802 copper Inorganic materials 0.000 claims abstract description 25
- 239000010949 copper Substances 0.000 claims abstract description 25
- 229910000881 Cu alloy Inorganic materials 0.000 claims abstract description 23
- 239000000463 material Substances 0.000 claims abstract description 20
- 238000000034 method Methods 0.000 claims abstract description 20
- 229910052751 metal Inorganic materials 0.000 claims abstract description 18
- 239000002184 metal Substances 0.000 claims abstract description 18
- 238000005406 washing Methods 0.000 claims description 11
- 239000000126 substance Substances 0.000 abstract description 5
- 231100000252 nontoxic Toxicity 0.000 abstract description 3
- 230000003000 nontoxic effect Effects 0.000 abstract description 3
- 239000002904 solvent Substances 0.000 abstract description 3
- 239000003795 chemical substances by application Substances 0.000 abstract description 2
- 150000002739 metals Chemical class 0.000 abstract description 2
- 230000000694 effects Effects 0.000 description 11
- 229910052782 aluminium Inorganic materials 0.000 description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 8
- 239000011888 foil Substances 0.000 description 8
- 238000005516 engineering process Methods 0.000 description 6
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 6
- 239000008399 tap water Substances 0.000 description 6
- 235000020679 tap water Nutrition 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 230000006378 damage Effects 0.000 description 5
- 229920000742 Cotton Polymers 0.000 description 3
- 239000003153 chemical reaction reagent Substances 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 239000004744 fabric Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 229910001961 silver nitrate Inorganic materials 0.000 description 3
- 238000012800 visualization Methods 0.000 description 3
- 210000004243 sweat Anatomy 0.000 description 2
- 229910001369 Brass Inorganic materials 0.000 description 1
- 239000010951 brass Substances 0.000 description 1
- 230000001680 brushing effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 210000000887 face Anatomy 0.000 description 1
- 238000003958 fumigation Methods 0.000 description 1
- 210000004907 gland Anatomy 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000008204 material by function Substances 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000002435 rhinoplasty Methods 0.000 description 1
- 230000028327 secretion Effects 0.000 description 1
- 208000017520 skin disease Diseases 0.000 description 1
- 238000002791 soaking Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
- 238000001771 vacuum deposition Methods 0.000 description 1
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/117—Identification of persons
- A61B5/1171—Identification of persons based on the shapes or appearances of their bodies or parts thereof
- A61B5/1172—Identification of persons based on the shapes or appearances of their bodies or parts thereof using fingerprinting
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- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Medical Informatics (AREA)
- Biophysics (AREA)
- Pathology (AREA)
- Engineering & Computer Science (AREA)
- Biomedical Technology (AREA)
- Heart & Thoracic Surgery (AREA)
- Physics & Mathematics (AREA)
- Molecular Biology (AREA)
- Surgery (AREA)
- Animal Behavior & Ethology (AREA)
- General Health & Medical Sciences (AREA)
- Public Health (AREA)
- Veterinary Medicine (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
The invention discloses application of a sulfur-nitrogen polymer in fingerprint appearance. Placing a material to be detected above the sulfur-nitrogen polymer to show fingerprints, wherein the material to be detected is metal, preferably copper or copper alloy; the surface of the material to be tested is not damaged or is a damaged surface. The invention provides a new showing method aiming at showing potential fingerprints on metals, particularly copper and copper alloys, and particularly adopts a sulfur-nitrogen polymer as a fingerprint showing agent, which belongs to a non-toxic material, does not need to add a chemical solvent additionally, and is safe and environment-friendly to use; the fingerprint, the lines and the background which are shown by the sulfur-nitrogen polymer have obvious contrast and can be directly photographed and extracted, thereby providing trace evidence for court judgement.
Description
Technical Field
The invention relates to application of a sulfur-nitrogen polymer in fingerprint visualization, belonging to the technical field of court science.
Background
Since 1877, a french doctor Aubert showed sweat fingerprints using a silver nitrate solution for hundreds of years, and in the process of researching skin diseases and gland secretion, he coated a silver nitrate solution on paper to show sweat fingerprints, and thus became a rhinoplasty for creating a fingerprint showing technology. Fingerprint display is a professional technology which comprehensively uses multiple disciplines including chemistry, biology, physics and the like from a simple solution display method to the present. With the development of modern instruments, detection technologies and novel functional materials, people do not limit the exploration of fingerprints to the application of traditional physical and chemical methods any more, and various emerging technologies are developed at the same time. Over the past hundred years, the technology of fingerprint visualization has advanced greatly, but still faces many problems which are difficult to solve. For example, there are no well developed reagents and methods for fingerprints left on the surface of objects of a particular structure or material; some show that the reagent has toxicity, and long-term contact can affect health; and the partial display method generates unrecoverable damage to the fingerprint and the valuable material evidence, and the like. Thus, there is still a need to develop better potential fingerprint appearance techniques.
Fingerprints are different from person to person and have uniqueness; once a fingerprint is formed, its minutiae remain unchanged for life, with relative stability. Depending on the uniqueness and stability of the fingerprint, the real identity of a person can be verified, which is the fingerprint identification technology. Fingerprint identification is one of the most reliable methods for individual identification, used in forensic science to effectively verify and verify criminal facts, and fingerprint and DNA are collectively called the king of evidence.
The hand prints on the metal surface are a plurality of traces in the material evidence of the criminal crime scene, most of key material evidences, especially the crime tools are made of metal materials, so the hand prints on the metal surface are shown, the criminal suspect and the case have high degree of correlation, the criminal suspect has strong directivity for detecting and solving the case, the hand prints left on the metal surface of the criminal suspect can be timely found and clearly shown and extracted, and the criminal suspect has an important effect on detecting the case.
At present, the most commonly used method for developing the metal surface fingerprint mainly comprises the methods of '502' fuming, powder brushing, vacuum coating and the like. Wherein, the '502' fumigation has certain display effect on fresh or short-time surface fingerprints; the particle suspension has certain display effect on the surface of the stainless steel; the silver nitrate solution has certain effect on brass objects, and in general, the traditional methods have certain effect on fresh metal surface hand prints which are good in leaving condition and mild in environment. However, the fingerprints on the metal surface have a plurality of influence factors including metal components, properties, forms, environmental conditions, fingerprint leaving conditions and the like. The condition of the fingerprint on the metal surface is relatively complex when the real crime scene meets, for example, after the fingerprint is influenced by special conditions such as washing, soaking and the like, the fingerprint remaining substance on the metal surface is removed, the fingerprint showing success rate under the conditions is generally low, and the problem of solving the fingerprint showing difficulty of the difficult objects becomes a new direction for research.
Disclosure of Invention
The invention aims to provide the application of the sulfur-nitrogen polymer in fingerprint display, which can provide trace evidence for court judgment; the developed fingerprint has obvious contrast with the background, and can be directly photographed and extracted.
The S-N polymer, namely (SN) x, x is a number between 15 and 35, has high anisotropy and metallicity, and has good metallicity conductivity in a direction parallel to an S-N chain; in the vertical direction, the conductivity is much worse. The sulfur-nitrogen polymer is a non-toxic material, and when fingerprint display is carried out, no additional chemical solvent is needed, so that the use is safe and environment-friendly.
The sulfur-nitrogen polymer is capable of developing fingerprints on metal surfaces, particularly fingerprints on copper or copper alloy surfaces.
When the sulfur-nitrogen polymer is applied, the surface of the material to be detected, on which the fingerprint is printed, is placed above the sulfur-nitrogen polymer, so that the fingerprint can be displayed;
the sulfur-nitrogen polymer can be placed in an aluminum foil container, and the material to be detected is placed above the sulfur-nitrogen polymer;
the distance between the two can be adjusted according to the specific requirements, for example, an aluminum foil container with an inner diameter of 30cm and a height of 40cm is adopted, and the material to be measured needs to be placed at a height not greater than 15 cm.
The present invention can reveal surfaces of materials that are either undamaged or damaged.
Specifically, the surface of the material to be tested can be damaged in any form of the following:
washing and wiping;
such as a surface destroyed by washing with tap water, washing with a washing solution, wiping with cotton cloth, etc.
The fingerprint of the metal surface can be displayed under the condition of low temperature or heating the sulfur-nitrogen polymer, and specifically, the fingerprint can be displayed under the condition of 0-70 ℃, such as the low temperature of 0-5 ℃ or the heating condition of 65-70 ℃, even if the sulfur-nitrogen polymer is in the low temperature environment of 0-5 ℃, or the sulfur-nitrogen polymer is heated to 65-70 ℃.
The sulfur-nitrogen polymer can show fingerprints formed on the surface of copper or copper alloy within 1-4 hours and 40 days or longer.
After the potential fingerprints on the surface of the copper or the copper alloy are shown by the sulfur-nitrogen polymer, the shown fingerprints can be directly observed by naked eyes.
The invention can realize the fingerprint display within 24 hours, within 72 hours, for one week or longer of natural storage on the surface of copper or copper alloy.
The invention provides a new showing method aiming at showing potential fingerprints on metals, particularly copper and copper alloys, and particularly adopts a sulfur-nitrogen polymer as a fingerprint showing agent, which belongs to a non-toxic material, does not need to add a chemical solvent additionally, and is safe and environment-friendly to use; the fingerprint, the lines and the background which are shown by the sulfur-nitrogen polymer have obvious contrast and can be directly photographed and extracted, thereby providing trace evidence for court judgement.
Drawings
FIG. 1 shows the results after 40 days of development with a thionitrogen polymer 24 hours after the formation of a latent fingerprint on the copper surface without destruction.
FIG. 2 shows the results of the copper alloy surface after the formation of the latent fingerprints for 4 hours, which were developed with the thionitrogen polymer, 72 hours after the formation of the fingerprints.
FIG. 3 shows the results of the development of a sulfur-nitrogen polymer after 1 hour, 7 days after the formation of a latent fingerprint on the copper surface without destruction.
FIG. 4 shows the result of 1 hour after the copper alloy surface latent fingerprint is formed for 12 hours, washed by tap water, dried and developed by the sulfur-nitrogen polymer.
FIG. 5 shows the results of 12 hours after the formation of a latent fingerprint on the copper surface, the copper surface was rubbed with a soft cotton cloth several times in a washing solution, washed with tap water, dried, and developed with a thionitrogen polymer for 1 hour.
Detailed Description
The experimental procedures used in the following examples are all conventional procedures unless otherwise specified.
Materials, reagents and the like used in the following examples are commercially available unless otherwise specified.
Example 1 copper and copper alloy latent fingerprints were visualized with polymers without destruction
Taking copper or copper alloy sheet (6 cm long and 2.5cm wide), and naturally stamping for later use. 1.5-3 g of sulfur-nitrogen polymer (x is 20-25) is displayed after a certain time and observed by naked eyes, and the result is as follows:
the potential fingerprints in the following states are displayed in the same way: the sulfur-nitrogen polymer is placed in an aluminum foil container (the inner diameter is 30cm, and the height is 40cm), and then a copper or copper alloy sheet is hung at the height of 10cm above the container, so that fingerprints can be displayed;
1. the potential fingerprints on the copper surface are not damaged, and after the fingerprints are left for 24 hours, the fingerprints are displayed for 40 days at a low temperature of 0-5 ℃, and the displayed effect is shown in figure 1.
2. The potential fingerprints on the surface of the copper alloy are not damaged, the aluminum foil container is properly heated to 65-70 ℃ after the fingerprints are left for 72 hours, and the effect is shown in figure 2 after the fingerprints are displayed for 4 hours.
3. The potential fingerprints on the copper surface are not damaged, 7 days after the fingerprints are left, the aluminum foil container is properly heated to 65-70 ℃ and is displayed for 1 hour, and the displayed effect is shown in figure 3.
Example 2 visualization of copper and copper alloy latent fingerprints Using polymers after destruction in some way
Taking copper or copper alloy sheet (6 cm long and 2.5cm wide), and naturally stamping for later use. 1.5-3 g of sulfur-nitrogen polymer (x is 20-25) is displayed after a certain time and observed by naked eyes, and the result is as follows:
the potential fingerprints in the following states are displayed in the same way: the sulfur-nitrogen polymer was placed in an aluminum foil container (inner diameter 30cm, height 40cm), and then a copper or copper alloy piece was suspended at a height of 10cm above,
1. after 12 hours of printing of the latent fingerprints on the surface of the copper alloy, slowly washing the surface of the copper alloy with tap water once, then drying the printed surface of the copper alloy, properly heating an aluminum foil container to 65-70 ℃, and displaying the printed surface of the copper alloy for 1 hour, wherein the displayed effect is shown in figure 4.
2. After 12 hours of printing of the latent fingerprints on the copper surface, a proper amount of tap water is added into two drops of washing liquid to be uniformly stirred, the copper sheet is put into the washing liquid, after the copper sheet is lightly wiped by soft cotton cloth, the residual washing liquid is slowly washed away by the tap water to be dried, an aluminum foil container is properly heated to 65-70 ℃ to be developed for 1 hour, and the developed effect is shown in figure 5.
The above-mentioned display effect shows that the sulfur-nitrogen polymer has good display result for the indestructible and destroyed latent fingerprints left on the surface lines of copper and copper alloy after being processed by different display time and different display temperature, and the displayed fingerprint lines and background contrast is obvious, and can be directly photographed and extracted.
Claims (10)
1. The application of the sulfur-nitrogen polymer in fingerprint appearance.
2. Use according to claim 1, characterized in that: the sulfur nitrogen polymer is used for revealing fingerprints on metal surfaces.
3. Use according to claim 2, characterized in that: the metal is copper or a copper alloy.
4. A method of fingerprint presentation comprising the steps of: and placing the surface of the material to be detected, on which the fingerprint is printed, above the sulfur-nitrogen polymer to display the fingerprint.
5. The method of claim 4, wherein: the material to be detected is metal.
6. The method of claim 5, wherein: the metal is copper or a copper alloy.
7. The method according to any one of claims 4-6, wherein: the surface of the material to be tested is not damaged or is a damaged surface.
8. The method of claim 7, wherein: the surface of the material to be tested is damaged in any one of the following forms:
washing and wiping.
9. The method according to any one of claims 4-8, wherein: fingerprints appear within 1h to 4h or 40 days after the sulfur-nitrogen polymer is applied.
10. The method according to any one of claims 4-9, wherein: fingerprint display is carried out at the temperature of 0-70 ℃;
the developed fingerprint was visually observed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011219677.6A CN112315460A (en) | 2020-11-04 | 2020-11-04 | Application of sulfur-nitrogen polymer in fingerprint display |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011219677.6A CN112315460A (en) | 2020-11-04 | 2020-11-04 | Application of sulfur-nitrogen polymer in fingerprint display |
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| Publication Number | Publication Date |
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| CN112315460A true CN112315460A (en) | 2021-02-05 |
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| CN202011219677.6A Pending CN112315460A (en) | 2020-11-04 | 2020-11-04 | Application of sulfur-nitrogen polymer in fingerprint display |
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110402235A (en) * | 2017-03-14 | 2019-11-01 | 英国国防部 | Prepare the method for the metal halide adduct of S4N4 and by the mark visualization method and equipment on object |
| GB2578815A (en) * | 2018-09-14 | 2020-05-27 | Secr Defence | Apparatus and associated accessories, methods and uses for visualising a print on an object |
| CN112357895A (en) * | 2020-11-04 | 2021-02-12 | 公安部物证鉴定中心 | Preparation method and device of sulfur-nitrogen polymer |
-
2020
- 2020-11-04 CN CN202011219677.6A patent/CN112315460A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110402235A (en) * | 2017-03-14 | 2019-11-01 | 英国国防部 | Prepare the method for the metal halide adduct of S4N4 and by the mark visualization method and equipment on object |
| US20200046266A1 (en) * | 2017-03-14 | 2020-02-13 | The Secretary Of State For Defence | Methods and apparatus for visualising a print on an object |
| GB2578815A (en) * | 2018-09-14 | 2020-05-27 | Secr Defence | Apparatus and associated accessories, methods and uses for visualising a print on an object |
| CN112357895A (en) * | 2020-11-04 | 2021-02-12 | 公安部物证鉴定中心 | Preparation method and device of sulfur-nitrogen polymer |
Non-Patent Citations (1)
| Title |
|---|
| PAUL F. KELLY, ET AL.: "Fingerprint and inkjet-trace imaging using disulfur dinitride", 《CHEMICAL COMMUNICATIONS》, pages 6111 - 6113 * |
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