Multi-frequency coupled ultrasonic scalpel

Abstract

This invention relates to a multi-frequency coupled vibration ultrasonic scalpel, comprising: a scalpel handle; at least two piezoelectric ceramic groups, each having a corresponding resonant frequency of the same order when excited; at least one insulating block located between two adjacent piezoelectric ceramic groups; a connecting rod connected to the scalpel handle, with the piezoelectric ceramic groups and the insulating block passing through the connecting rod and pressed against each other; exciting at least one piezoelectric ceramic group to vibrate at at least two resonant frequencies, or exciting at least two piezoelectric ceramic groups to vibrate at at least one resonant frequency, so that the scalpel handle vibrates at a frequency resulting from the coupling of at least two resonant frequencies generated by the piezoelectric ceramic groups. This invention has multiple resonant frequencies and can be driven simultaneously by alternating current corresponding to each frequency, thereby generating multi-frequency coupled vibration at the scalpel tip to improve the cutting and coagulation effects on tissues.

Description

Technical Field

[0001] This invention relates to the field of medical devices, and more particularly to an ultrasonic scalpel with multi-frequency coupled vibration, and especially to an ultrasonic scalpel with multi-frequency coupled vibration capable of converting electrical energy into mechanical energy. Background Technology

[0002] Currently, ultrasonic scalpels are widely used in various surgical procedures. Compared to traditional surgical equipment, ultrasonic scalpels offer advantages such as high precision, minimal invasiveness, and easier postoperative recovery. The working principle of an ultrasonic scalpel is to use a simple harmonic alternating current to drive a piezoelectric ultrasonic transducer to generate vibrations, thereby achieving tissue cutting and coagulation. The amplitude of the ultrasonic scalpel directly determines the effectiveness of cutting and coagulation. If the amplitude of the ultrasonic scalpel is inappropriate, it may result in poor cutting and coagulation effects, leading to tissue bleeding or damage to other normal tissues, and even endangering the patient's life. Therefore, controlling the amplitude of the ultrasonic scalpel to achieve optimal cutting and coagulation results is crucial.

[0003] Currently, ultrasonic scalpels are mainly driven by simple harmonic alternating current in the form of continuous or pulsed current at a single frequency. The blade of the ultrasonic scalpel also generates regular simple harmonic vibrations. Under a single vibration frequency, the cutting and coagulation effects on tissues are greatly limited, and the actual use effect is not ideal.

[0004] Therefore, based on years of experience and practice in related industries, the inventor proposes a multi-frequency coupled vibration ultrasonic scalpel to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide an ultrasonic scalpel with multi-frequency coupled vibration, which has multiple resonant frequencies and can be driven simultaneously by the alternating current corresponding to each frequency, thereby generating multi-frequency coupled vibration at the scalpel head to improve the cutting and coagulation effect on tissues and increase the success rate of surgery.

[0006] The objective of this invention can be achieved through the following methods:

[0007] This invention provides an ultrasonic surgical scalpel with multi-frequency coupled vibration, comprising:

[0008] Tool holder;

[0009] At least two piezoelectric ceramic groups, each having a different thickness, and in the excited state, each having a different resonant frequency of the same order;

[0010] At least one insulating block is located between two adjacent piezoelectric ceramic groups;

[0011] A connecting rod is connected to the blade rod, the piezoelectric ceramic assembly and the insulating block are inserted through the connecting rod, and the piezoelectric ceramic assembly, the insulating block and the blade rod are pressed together;

[0012] In a preferred embodiment of the present invention, when each of the piezoelectric ceramic groups is excited by an alternating current of a corresponding frequency, the difference between the same-order resonant frequencies of any two of the excited piezoelectric ceramic groups is less than 10 kHz.

[0013] In a preferred embodiment of the present invention, when at least one of the piezoelectric ceramic groups is excited by two different alternating currents, the two different resonant frequencies of the piezoelectric ceramic groups are both in the frequency range of 20kHz to 80kHz.

[0014] In a preferred embodiment of the present invention, the difference between the two different resonant frequencies of the piezoelectric ceramic assembly is greater than 20 kHz.

[0015] In a preferred embodiment of the present invention, the multi-frequency coupled vibration ultrasonic scalpel further includes a rear cover, the piezoelectric ceramic assembly and the insulating block are pressed between the rear cover and the scalpel rod, and the rear cover, the piezoelectric ceramic assembly and the insulating block are all mounted on the connecting rod.

[0016] In a preferred embodiment of the present invention, the back cover is made of a metal material.

[0017] In a preferred embodiment of the present invention, the connecting rod is a bolt.

[0018] In a preferred embodiment of the present invention, the piezoelectric ceramic assembly includes a plurality of voltage ceramic sheets, each of which is stacked and an electrode sheet is disposed between adjacent voltage ceramic sheets.

[0019] In a preferred embodiment of the present invention, the insulating block is made of a rigid insulating material, and the density of the insulating block is 2000 kg / m³. 3 Up to 5000 kg / m 3 The elastic modulus of the insulating block is 300 GPa to 400 GPa.

[0020] As described above, the features and advantages of the multi-frequency coupled vibration ultrasonic scalpel of the present invention are as follows: the ultrasonic scalpel has at least two piezoelectric ceramic groups, each of which has a corresponding resonant frequency of the same order when excited; an insulating block is provided between two adjacent piezoelectric ceramic groups, and the piezoelectric ceramic groups and the insulating block are connected by a connecting rod and pressed together with the scalpel handle; by exciting at least one piezoelectric ceramic group to vibrate at at least two resonant frequencies, or by exciting at least two piezoelectric ceramic groups to vibrate at at least one resonant frequency, at least two frequencies of vibration can be generated, so that the scalpel handle vibrates at the frequency after coupling at least two resonant frequencies. Since there are multiple piezoelectric ceramic groups, the present invention can be driven simultaneously by AC power corresponding to each frequency, so that each piezoelectric ceramic group can have multiple resonant frequencies, thereby enabling the scalpel handle to generate multi-frequency coupled vibration, thereby improving the cutting and coagulation effect on tissues and increasing the success rate of surgery. Attached Figure Description

[0021] The accompanying drawings are intended only to illustrate and explain the present invention and do not limit the scope of the invention.

[0022] in:

[0023] Figure 1 : This is a schematic diagram of the structure of the ultrasonic surgical scalpel with multi-frequency coupled vibration of the present invention.

[0024] Figure 2 This is a schematic diagram of the structure of the ultrasonic surgical scalpel with two piezoelectric ceramic groups in the multi-frequency coupled vibration of the present invention.

[0025] Figure 3 :for Figure 2 One of the curves of amplitude versus time for an ultrasonic scalpel with multi-frequency coupled vibration.

[0026] Figure 4 :for Figure 2 The second graph shows the amplitude versus time curve of an ultrasonic scalpel with multi-frequency coupled vibration.

[0027] Figure 5 :for Figure 2 The third graph of the amplitude versus time of an ultrasonic scalpel with multi-frequency coupled vibration.

[0028] Figure 6 This is a schematic diagram of the structure of the ultrasonic surgical scalpel with three piezoelectric ceramic groups in the multi-frequency coupled vibration of the present invention.

[0029] Figure 7 :for Figure 6 One of the curves of amplitude versus time for an ultrasonic scalpel with multi-frequency coupled vibration.

[0030] The reference numerals in the accompanying drawings of this invention are:

[0031] 1. Tool holder; 2. Piezoelectric ceramic assembly;

[0032] 3. Insulating block; 4. Back cover;

[0033] 5. Connecting rod. Detailed Implementation

[0034] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0035] like Figure 1 The present invention provides a multi-frequency coupled vibration ultrasonic scalpel, which includes a scalpel handle 1, at least two piezoelectric ceramic groups 2, at least one insulating block 3, and a connecting rod 5. In the excited state, each piezoelectric ceramic group 2 has a corresponding resonant frequency of the same order; the insulating block 3 is located between two adjacent piezoelectric ceramic groups 2; the connecting rod 5 is connected to the scalpel handle 1, and the piezoelectric ceramic groups 2 and the insulating block 3 are passed through the connecting rod 5, and the piezoelectric ceramic groups 2, the insulating block 3, and the scalpel handle 1 are pressed together; by exciting at least one piezoelectric ceramic group 2 to vibrate at at least two resonant frequencies, or by exciting at least two piezoelectric ceramic groups 2 to vibrate at at least one resonant frequency, the scalpel handle 1 vibrates at the frequency resulting from the coupling of at least two resonant frequencies generated by the piezoelectric ceramic groups 2.

[0036] Each piezoelectric ceramic group 2 is excited by an alternating current of a corresponding frequency to excite at least two piezoelectric ceramic groups 2 to vibrate at their corresponding resonant frequencies, so that the tool holder 1 vibrates at the frequency after coupling the resonant frequencies of each piezoelectric ceramic group 2; or at least one piezoelectric ceramic group 2 is excited by two different alternating currents to excite at least one piezoelectric ceramic group 2 to vibrate at two different resonant frequencies, so that the tool holder 1 vibrates at the frequency after coupling the resonant frequencies of each piezoelectric ceramic group 2.

[0037] In this invention, the ultrasonic scalpel has at least two piezoelectric ceramic groups 2. In the excited state, each piezoelectric ceramic group 2 has a corresponding resonant frequency of the same order. An insulating block 3 is provided between two adjacent piezoelectric ceramic groups 2. The piezoelectric ceramic groups 2 and the insulating block 3 are connected by a connecting rod 5 and pressed together with the scalpel rod 1. During use, at least one piezoelectric ceramic group 2 is excited to vibrate at at least two resonant frequencies, or at least two piezoelectric ceramic groups 2 are excited to vibrate at at least one resonant frequency, thereby generating at least two frequencies of vibration. The vibration of the piezoelectric ceramic groups 2 is transmitted to the scalpel rod 1, causing the scalpel rod 1 to vibrate at the frequency resulting from the coupling of at least two resonant frequencies corresponding to each piezoelectric ceramic group 2. Since there are multiple piezoelectric ceramic groups 2, this invention can be driven simultaneously by AC power corresponding to each frequency, so that each piezoelectric ceramic group 2 can have multiple resonant frequencies, thereby enabling the scalpel rod 1 to generate multi-frequency coupled vibration (non-harmonic vibration), thereby improving the cutting and coagulation effect on tissues and increasing the success rate of surgery.

[0038] In an optional embodiment of the present invention, such as Figure 1 The piezoelectric ceramic assembly 2 has a different thickness, so that each piezoelectric ceramic assembly 2 has a different resonant frequency of the same order. The thickness of each piezoelectric ceramic assembly 2 can be set according to the multi-frequency coupled vibration required by the ultrasonic scalpel under actual use, so that each piezoelectric ceramic assembly 2 is excited to vibrate at its corresponding resonant frequency of the same order, so that the scalpel handle 1 vibrates at the frequency after coupling with the corresponding resonant frequencies of each piezoelectric ceramic assembly 2.

[0039] In this embodiment, the difference between the same-order resonant frequencies of any two piezoelectric ceramic groups 2 that are excited is less than 10kHz.

[0040] Furthermore, in at least two piezoelectric ceramic groups 2, each piezoelectric ceramic group 2 is excited by an alternating current of a corresponding frequency to excite at least two piezoelectric ceramic groups 2 to vibrate at the corresponding resonant frequency, so that the tool holder 1 vibrates at the frequency after coupling with the resonant frequencies of the corresponding piezoelectric ceramic groups 2.

[0041] For example, there are three piezoelectric ceramic groups 2, and their resonant frequencies when excited are f1, f2, and f3, respectively. In actual use, two piezoelectric ceramic groups 2 can be excited separately using AC power as needed, causing them to vibrate at the same resonant frequencies of f1 and f2 (or f1 and f3, or f2 and f3). The scalpel handle 1 then vibrates at the frequency resulting from the coupling of the resonant frequencies of the two excited piezoelectric ceramic groups 2, i.e., the ultrasonic scalpel's vibration mode is a dual-frequency coupled vibration mode. Alternatively, all three piezoelectric ceramic groups 2 can be excited separately using AC power as needed, causing them to vibrate at the same resonant frequencies of f1, f2, and f3, respectively. The scalpel handle 1 then vibrates at the frequency resulting from the coupling of the resonant frequencies of the three excited piezoelectric ceramic groups 2, i.e., the ultrasonic scalpel's vibration mode is a three-frequency coupled vibration mode. By analogy, when there are multiple piezoelectric ceramic groups 2, and the same-order resonant frequencies of the multiple piezoelectric ceramic groups 2 when excited are f1, f2, f3, etc., any number (greater than or equal to two groups) of piezoelectric ceramic groups 2 can be selected for excitation according to actual use needs, so that the scalpel 1 vibrates at the frequency after coupling the same-order resonant frequencies of the multiple excited piezoelectric ceramic groups 2, that is, the vibration mode of the ultrasonic scalpel is a multi-frequency coupled vibration mode.

[0042] In an optional embodiment of the present invention, in at least two piezoelectric ceramic groups 2, at least one piezoelectric ceramic group 2 is excited by two different alternating currents to excite at least one piezoelectric ceramic group 2 to vibrate at two different resonant frequencies, so that the tool bar 1 vibrates at the frequency after coupling the resonant frequencies corresponding to each piezoelectric ceramic group 2.

[0043] In this embodiment, the two different resonant frequencies of the piezoelectric ceramic group 2 are both in the frequency range of 20kHz to 80kHz, and the difference between the two different resonant frequencies of the piezoelectric ceramic group is greater than 20kHz.

[0044] For example, there are two piezoelectric ceramic groups 2 (i.e., the first piezoelectric ceramic group and the second piezoelectric ceramic group). The first piezoelectric ceramic group can be excited by two different AC currents so that it can vibrate at two different resonant frequencies, F1 and F2. The second piezoelectric ceramic group can be excited by two different AC currents so that it can vibrate at two different resonant frequencies, F3 and F4. In practical use, each piezoelectric ceramic group 2 can be excited by a single AC current according to the required vibration frequency at the tool holder 1 (i.e., the first piezoelectric ceramic group vibrates at the resonant frequency of F1 or F2, and the second piezoelectric ceramic group vibrates at the resonant frequency of F3 or F4), or each piezoelectric ceramic group 2 can be excited by two different AC currents (i.e., the first piezoelectric ceramic group vibrates at the resonant frequencies of F1 and F2 simultaneously, and the second piezoelectric ceramic group vibrates at the resonant frequencies of F3 and F4 simultaneously), or one piezoelectric ceramic group 2 can be excited by a single AC current, while the other piezoelectric ceramic group 2 can be excited by two different AC currents (i.e., the first piezoelectric ceramic group vibrates at the resonant frequency of F1 or F2, and the second piezoelectric ceramic group vibrates at the resonant frequencies of F3 and F4 simultaneously; or the first piezoelectric ceramic group vibrates at the resonant frequencies of F1 and F2 simultaneously, and the second piezoelectric ceramic group vibrates at the resonant frequency of F3 or F4).

[0045] For example, the number of piezoelectric ceramic groups 2 is three (i.e., the first piezoelectric ceramic group, the second piezoelectric ceramic group, and the third piezoelectric ceramic group). The first piezoelectric ceramic group can be excited by two different AC frequencies to vibrate at two different resonant frequencies, F1 and F2. The second piezoelectric ceramic group can be excited by two different AC frequencies to vibrate at two different resonant frequencies, F3 and F4. The third piezoelectric ceramic group can be excited by two different AC frequencies to vibrate at two different resonant frequencies, F5 and F6. In practical use, depending on the required vibration frequency at the blade shank 1, each piezoelectric ceramic group 2 can be excited by either only one AC frequency or by two AC frequencies simultaneously. Different vibration combinations are formed according to the different resonant frequencies of each piezoelectric ceramic group 2, so that the blade shank 1 vibrates at the frequency resulting from the coupling of the resonant frequencies corresponding to the multiple excited piezoelectric ceramic groups 2. That is, the vibration mode of the ultrasonic scalpel is a multi-frequency coupled vibration mode.

[0046] In one specific embodiment of the present invention, such as Figure 2As shown, there are two piezoelectric ceramic groups 2, arranged sequentially from the direction furthest from the tool holder 1 to the direction closest to it. The thickness of the first piezoelectric ceramic group is 3mm, and the thickness of the second piezoelectric ceramic group is 5mm. The diameter of both the first and second piezoelectric ceramic groups is 14mm. The length of the tool holder 1 is 80mm. When the first piezoelectric ceramic group is excited, its resonant frequencies can be 22650Hz and 60217Hz; when the second piezoelectric ceramic group is excited, its resonant frequencies can be 22757Hz and 60686Hz. Therefore, the first and second piezoelectric ceramic groups can have up to four resonant frequencies. In actual use, two, three, or all four resonant frequencies can be selected for coupling. For example, the first piezoelectric ceramic group can be excited by AC current with a frequency of 22650Hz, and the second piezoelectric ceramic group can be excited by AC current with a frequency of 22757Hz. Figure 3 As shown, the vibration generated at tool holder 1 (specifically, the front end of tool holder 1) is a dual-frequency coupled vibration; for example, the first piezoelectric ceramic group is excited by AC current with frequencies of 22650Hz and 60217Hz respectively, and the second piezoelectric ceramic group is excited by AC current with a frequency of 22757Hz, as shown. Figure 4 As shown, the vibration generated at tool holder 1 (specifically, the front end of tool holder 1) is a three-frequency coupled vibration; for example, the first piezoelectric ceramic group is excited by AC currents with frequencies of 22650Hz and 60217Hz respectively, and the second piezoelectric ceramic group is excited by AC currents with frequencies of 22757Hz and 60217Hz respectively, as shown. Figure 5 As shown, the vibration generated at tool holder 1 (specifically, the front end of tool holder 1) is a four-frequency coupled vibration. The coupling methods for other resonant frequency combinations are excited according to the implementation method described above, and will not be repeated here.

[0047] In another specific embodiment of the present invention, such as Figure 6As shown, there are three piezoelectric ceramic groups 2, arranged sequentially from the furthest point from the tool holder 1 to the closest point: the first piezoelectric ceramic group, the second piezoelectric ceramic group, and the third piezoelectric ceramic group. The thickness of the first piezoelectric ceramic group is 6 mm, the thickness of the second piezoelectric ceramic group is 3 mm, and the thickness of the third piezoelectric ceramic group is 5 mm. The diameter of the first, second, and third piezoelectric ceramic groups is 14 mm. The length of the tool holder 1 is 80 mm. When the first piezoelectric ceramic group is excited, the resonant frequencies can be 21559 Hz and 57988 Hz; when the second piezoelectric ceramic group is excited, the resonant frequencies can be 21670 Hz and 58286 Hz; and when the third piezoelectric ceramic group is excited, the resonant frequencies can be 21681 Hz and 58139 Hz. Therefore, the first, second, and third piezoelectric ceramic groups can have up to six resonant frequencies. In actual use, two, three, four, five, or six of these resonant frequencies can be selected for coupling. For example: the first piezoelectric ceramic group is excited with AC currents of 21559Hz and 57988Hz respectively; the second piezoelectric ceramic group is excited with AC currents of 21670Hz and 58286Hz respectively; and the third piezoelectric ceramic group is excited with AC currents of 21681Hz and 58139Hz respectively. Figure 7 As shown, the vibration generated at tool holder 1 (specifically, the front end of tool holder 1) is a six-frequency coupled vibration. Other coupling methods for resonant frequency combinations are excited according to the implementation method described above, and will not be repeated here.

[0048] Of course, in order to excite multi-frequency (six or more frequencies) coupled vibration, the present invention can achieve multi-frequency (six or more frequencies) coupled vibration of the tool holder 1 by setting four or more piezoelectric ceramic groups 2.

[0049] In an optional embodiment of the present invention, when the tool holder 1 is vibrating at a coupled frequency, the length of the tool holder 1 is half a wavelength or an integer multiple of the wavelength.

[0050] In an optional embodiment of the invention, such as Figure 1 As shown, the ultrasonic scalpel with multi-frequency coupled vibration also includes a rear cover 4, a piezoelectric ceramic assembly 2 and an insulating block 3 pressed between the rear cover 4 and the scalpel rod 1. The rear cover 4, the piezoelectric ceramic assembly 2 and the insulating block 3 are all mounted on the connecting rod 5. The connecting rod 5 presses the rear cover 4, the piezoelectric ceramic assembly 2 and the insulating block 3 together and fixes them to the scalpel rod 1.

[0051] The back cover 4 may be made of, but is not limited to, high-density metal materials.

[0052] The connecting rod 5 can be, but is not limited to, a bolt. The connecting rod 5 can connect the various components (back cover 4, piezoelectric ceramic assembly 2, and insulating block 3) to form an ultrasonic scalpel assembly, and apply a certain prestress between the various parts.

[0053] Furthermore, such as Figure 1 As shown, the piezoelectric ceramic assembly 2 includes multiple voltage ceramic sheets, which are stacked in layers, and an electrode sheet is disposed between two adjacent voltage ceramic sheets.

[0054] Furthermore, the insulating block 3 may be made of, but is not limited to, a rigid insulating material, and the density of the insulating block 3 is 2000 kg / m³. 3 Up to 5000 kg / m 3 The elastic modulus of insulating block 3 is 300 GPa to 400 GPa.

[0055] The features and advantages of the multi-frequency coupled vibration ultrasonic scalpel of the present invention are as follows:

[0056] This multi-frequency coupled vibration ultrasonic scalpel has multiple piezoelectric ceramic groups 2 of different thicknesses, which can be driven simultaneously by alternating current corresponding to each frequency. This allows each piezoelectric ceramic group 2 to have multiple resonant frequencies, thereby enabling the scalpel handle 1 to generate multi-frequency coupled vibration, which improves the cutting and coagulation effect on tissues and effectively increases the success rate of surgery.

[0057] The above description is merely an illustrative embodiment of the present invention and is not intended to limit the scope of the invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. An ultrasonic surgical scalpel with multi-frequency coupled vibration, characterized in that, include: Tool holder; At least two piezoelectric ceramic groups, each having a different thickness, and in the excited state, each having a different resonant frequency of the same order; At least one insulating block is located between two adjacent piezoelectric ceramic groups; A connecting rod is connected to the blade rod, the piezoelectric ceramic assembly and the insulating block are inserted through the connecting rod, and the piezoelectric ceramic assembly, the insulating block and the blade rod are pressed together; Each of the piezoelectric ceramic groups is excited by an alternating current of a corresponding frequency to excite at least two of the piezoelectric ceramic groups to vibrate at the corresponding resonant frequency of the same order, and the vibration of the piezoelectric ceramic groups is transmitted to the tool holder so that the tool holder vibrates at the frequency after coupling the resonant frequencies of the corresponding piezoelectric ceramic groups. When each of the piezoelectric ceramic groups is excited by AC current of a corresponding frequency, the difference between the same-order resonant frequencies of any two of the excited piezoelectric ceramic groups is less than 10kHz. Alternatively, at least one of the piezoelectric ceramic groups can be excited by two different AC currents to induce at least one of the piezoelectric ceramic groups to vibrate at two different resonant frequencies, and the vibration of the piezoelectric ceramic groups can be transmitted to the tool bar so that the tool bar vibrates at the frequency after the resonant frequencies of each piezoelectric ceramic group are coupled together. When at least one of the piezoelectric ceramic groups is excited by two different AC currents, the two different resonant frequencies of the piezoelectric ceramic groups are both in the frequency range of 20kHz to 80kHz, and the difference between the two different resonant frequencies of the piezoelectric ceramic groups is greater than 20kHz.

2. The multi-frequency coupled ultrasonic surgical blade of claim 1, wherein, The multi-frequency coupled vibration ultrasonic scalpel also includes a rear cover, the piezoelectric ceramic assembly and the insulating block are pressed between the rear cover and the scalpel rod, and the rear cover, the piezoelectric ceramic assembly and the insulating block are all mounted on the connecting rod.

3. The multi-frequency coupled resonant ultrasonic surgical knife of claim 2, wherein, The back cover is made of metal.

4. The multi-frequency coupled resonant ultrasonic surgical knife of claim 2, wherein, The connecting rod is a bolt.

5. The multi-frequency coupled resonant ultrasonic surgical knife of claim 1, wherein, The piezoelectric ceramic assembly includes multiple voltage ceramic sheets, which are stacked in layers, and an electrode sheet is disposed between two adjacent voltage ceramic sheets.

6. The multi-frequency coupled resonant ultrasonic surgical knife of claim 1, wherein, The insulating block is made of a rigid insulating material with a density of 2000 kg / m³ to 5000 kg / m³ and an elastic modulus of 300 GPa to 400 GPa.

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