50results about How to "Increase relaxation time" patented technology

Devices and methods are described herein which are directed to the treatment of a patient's heart having, or one which is susceptible to heart failure, to improve diastolic function.

An atomic vapor cell apparatus and method for obtaining spin polarized vapor of alkali atoms with relaxation times in excess of one minute is provided. The interior wall of the vapor cell is coated with an alkene-based material. The preferred coatings are alkenes ranging from C18 to C30 and C20-C24 are particularly preferred. These alkene coating materials, can support approximately 1,000,000 alkali-wall collisions before depolarizing an alkali atom, an improvement by roughly a factor of 100 over traditional alkane-based coatings. Further, the method involves a combination of one or more of the following: the use of a locking device to isolate the atoms in the volume of the vapor cell from the sidearm used as a reservoir for the alkali metal vapor source, careful management of magnetic-field gradients, and the use of the spin-exchange-relaxation-free (SERF) technique for suppressing spin-exchange relaxation.

The invention relates to a precise control method of an atom spin SERF (Self-Exchange Relaxation-Free) state for stabilizing an atom spin device, which comprises the following steps that firstly, a precise equation is established for the atom spin SERF state, and a modulation method is adopted to measure the atom spin polarizability to establish a control target; then a control system model as precise as possible is established on the basis of an SERF model, and a parameter identification method is adopted to estimate unknown parameters of the model; and finally, according to the control target, a special structure design control law of the established model is fully used, i.e. the switching time, frequency, orientation and power of laser and the switching time of a modulation magnetic field are optimized, and the atom spin SERF state is precisely controlled in real time in accordance with a quantum control algorithm. By using the precise control method, the atom spin relaxation time is increased, and the problem of instability of scale factors of atom devices such as an atom spin gyroscope and an atom magnetometer based on the atom spin SERF effect is solved. The precise control method can be used for improving the long-time drift precision and the low-frequency sensitivity based on the SERF atom spin device.

A display apparatus has a switchable birefringent lens array. The display apparatus produces a substantially linearly polarised output. The lens array comprises birefringent material arranged between a planar surface of a first substrate and a relief substrate of a second substrate defining an array of cylindrical lenses. The lens array has electrodes for applying a control voltage across the birefringent material for electrically switching the birefringent material between a first mode and a second mode. In the first mode the lens array modifies the directional distribution of incident light polarised in a predetermined direction. In the second mode the lens array has substantially no effect on incident light polarised in said predetermined direction.

The production and usage of hyperpolarized 129Xenon which comprises providing solid xenon with either an internal (dissolved) or external (imbedded) nuclear spin relaxant, loading and positioning the solid xenon in a low temperature refrigerator operating in the range of 5 mK to 30 mK with a surrounding magnetic field of between about 10 and 20 Tesla enabling high xenon spin polarizations between about 10% and 50% to be obtained in a time of about 1-3 days owing to the properties of the relaxant, separating the xenon from the relaxant or otherwise rendering the relaxant inoperable after polarizing and thereby switching off further relaxation and insuring preservation of the polarization of the xenon in solid, liquid or gaseous form for storage or external use for long times, ranging from weeks to the order of minutes, depending on the usage conditions.

The present invention relates generally to nuclear magnetic resonance (NMR) techniques for both spectroscopy and imaging. More particularly, the present invention relates to methods in which hyperpolarized noble gases (e.g., Xe and He) are used to enhance and improve NMR and MRI. Additionally, the hyperpolarized gas solutions of the invention are useful both in vitro and in vivo to study the dynamics or structure of a system. When used with biological systems, either in vivo or in vitro, it is within the scope of the invention to target the hyperpolarized gas and deliver it to specific regions within the system.

A resonator element includes: at least one resonating arm extending, wherein the resonating arm has a mechanical resonance frequency which is higher than a thermal relaxation frequency thereof, the resonating arm has a groove portion, the groove portion includes a bottom portion, a first side surface that extends along the longitudinal direction of the resonating arm and comes into contact with the opened principal surface and the bottom portion, and a second side surface that faces the first side surface with the bottom portion disposed therebetween and comes into contact with the opened principal surface and the bottom portion, and the groove portion has a non-electrode region which extends from a part of the first side surface close to the bottom portion to a part of the second side surface close to the bottom portion and in which no electrode is provided.

Tunable, bio-functionalized, nanoelectromechanical systems (Bio-NEMS), micromechanical resonators (MRs), nanomechanical resonators (NRs), surface acoustic wave resonators, and bulk acoustic wave resonators having superhydrophobic surfaces for use in aqueous biochemical solutions. The MRs, NRs or Bio-NEMS include a system resonator that can vibrate or oscillate at a relatively high frequency and to which an analyte molecule(s) contained in the solution ○ can attach or upon which small molecular-scale forces can act; a device for adjusting a relaxation time of the solution, to increase the quality (Q-factor) of the resonator inside the solution, to reduce energy dissipation into the solution; and a device for detecting a frequency shift in the resonator due to the analyte molecule(s) or applied molecular-scale forces. The resonator can include roughness elements that provide superhydrophobicity and, more particularly, gaps between adjacent asperities for repelling the aqueous solution from the surface of the device.

A secondary controller drives a light emitting element of a photocoupler such that a detection voltage V_OUTS corresponding to an output voltage V_OUT generated in an output capacitor C approximates to a reference voltage V_REF. A primary controller controls a switching transistor M according to a feedback signal V_FB. A protection circuit is activated and drives the light emitting element of the photocoupler when detecting an abnormal state. An auxiliary power supply circuit includes a power supply capacitor C provided separately from the output capacitor C and supplies a power supply voltage V_CC to the protection circuit and an anode of the light emitting element of the photocoupler.

The invention discloses a long-chain branched high-density polyethylene material resisting environmental stress cracking and a preparation method thereof. According to the preparation method, long-chain branched modification is conducted on high-density polyethylene by selecting a melting reaction processing method to improve the environmental stress cracking resisting property of the material, branching generation is promoted by adding two-functionality-degree graft monomers, acrylic ester double bonds are adopted to stabilize the macromolecular free radicals and improve the branching efficiency, and meanwhile an efficient free radical regulating agent is added to regulate and control the activity of the macromolecular free radicals to inhibit crosslinking side reaction; the prepared long-chain branched high-density polyethylene has the low gel fraction, and long-branch-chain high-density polyethylene of which the branch chain length meets the stress cracking resisting requirement is obtained. The long-chain branched high-density polyethylene prepared through the preparation method has the excellent environmental stress cracking resisting property and the good comprehensive mechanical property.

In a first aspect this invention provides methods comprising administering an aqueous contrast agent to the vascular system of a subject, and performing a magnetic resonance scan to detect the MR signal enhancement effects of the aqueous contrast agent. In embodiments the magnetic resonance scan comprises applying at least one pulse sequence selected from a PD-weighted pulse sequence, a T1-weighted pulse sequence, a T2-weighted pulse sequence, and a D-weighted pulse sequence. In embodiments the magnetic resonance scan comprises applying a T1-weighted pulse sequence. A system for performing perfusion MRI comprising an aqueous contrast solution and an injection apparatus configured to provide a maximum injection rate of the aqueous contrast solution to a subject vascular system of at least about 5 ml/s. is also provided.

The invention provides an acrylamide copolymer, as well as a preparation method and an application thereof. The copolymer comprises a structural unit A, a structural unit B and a structural unit C, wherein the structural unit A is a unit having a structure as shown in a formula (1), the structural unit B is at least one unit having a structure as shown in formulae from (2) to (5), and the structural unit C is a unit having a structure as shown in a formula (6); the mass ratio of the structural unit A to structural unit B to structural unit C is 1:(0.001-3):(0.001-0.5); and the viscosity-average molecular weight of the acrylamide copolymer is 30-35 millions. A temperature-endurance salt-resistance product of the acrylamide copolymer has the characteristic of high molecular weight; and the acrylamide copolymer has an advantage of greatly thickening, and can be used as an oil-displacing agent for tertiary recovery of a high temperature and high salinity reservoir.

Deterioration of the Q value caused by the thermoelastic effect is suppressed. Since a first depth of a first groove and a second depth of a second groove are smaller than a distance between a surface including a third surface and a surface including a fourth surface, the first and second grooves do not penetrate between the surface including the third surface and the surface including the fourth surface. In addition, the sum of the first depth of the first groove and the second depth of the second groove is greater than the distance between the third and fourth surfaces, a heat transfer path between a first expandable portion (the first surface) and a second expandable portion (the second surface) cannot be formed as a straight line. As such, the heat transfer path between the first expandable portion (the first surface) and a second expandable portion (the second surface) is made to detour to the first and second grooves and and thus be lengthened.

The invention belongs to the technical field of measurement, specifically relates to a composite structure film for prolonging relaxation time of atomic magnetometers and a plating method of the composite structure film, and aims at improving the sensitivity of the atomic magnetometers. The composite structure film is plated on the inner wall of atom pool and consists of two parts: an inner-layer OTS film and an outer-layer olefin film. The composite structure film disclosed by the invention is capable of prolonging the relaxation time of alkali metal atoms and improving the high temperature resistance of films; through the OTS film, the high temperature resistance of relaxation films is improved, and an inhibiting effect to a certain extent is provided to the surface relaxation of the alkali metal atoms; and through adsorbing the olefin film on the surface of the OTS film, the advantages of the olefin film are utilized to remarkably improve the anti-relaxation effect of the films, the relaxation time of the alkali metal atoms is prolonged, and finally the sensitivity of the atomic magnetometers is improved.

The invention discloses an acrylamide copolymer, and a preparation method and an application thereof. The acrylamide monomer contains 85-98.9 wt% of a structure unit A with the structure represented by formula (1), 1-10 wt% of a structure unit B with the structure represented by formula (2) and 0.1-5 wt% of a structure unit C with the structure represented by formula (3); the viscosity average molecular weight of the acrylamide copolymer is 23-30 millions; and in the formula (1), the formula (2) and the formula (3), R1 to R3 can be same or different and are hydrogen or C1-C4 alkyl groups respectively independently, M is hydrogen, sodium or potassium, p is an integer in a range of 8-16, m is an integer in a range of 2-4, and n is an integer in a range of 3-9. The acrylamide copolymer has the advantages of high molecular weight, good temperature and salt resistance, and excellent surface activity.

The invention provides a bi-radical compound composed of a triaryl methyl radical and a nitroxide radical and salt thereof and a preparation method and application of the bi-radical compound composedof the triaryl methyl radical and the nitroxide radical and the salt thereof. A structural formula of the bi-radical compound is as shown in the formula 1; the formula is shown in the description; thepreparation method comprises the steps that a compound A1 and a compound A2 are subjected to acid amide condensation reaction to obtain a compound A3; the compound A3 and a compound A4 are subjectedto acid amide condensation reaction to obtain the bi-radical compound and the salt thereof. The portion, provided with both the nitroxide radical and the triaryl methyl radical, of a bi-radical polarization agent has the following advantages that the frequency matching ability is better, and the CE efficiency is higher; under a magic angle spinning condition, a depolarization effect does not exist, and a high field DNP enhancing effect is better; exchange interaction is stronger; the water solubility is good, so that the DNP enhancing multiple is high; by modifying R1, R2, R3, R4, R5 and R6 groups, exchange interaction can be improved moderately, bi-radical relaxation time can be prolonged moderately, and the bi-radical water solubility can be improved moderately, so that the DNP propertyof the polarization agent is improved.

The invention discloses a method for improving the near-infrared emission intensity of an up-conversion material. Ga<3+> is doped in the process of synthesizing the NaGdF4: 18%Yb and 0.5% Tm up-conversion material by adopting a solvothermal method, the NaGdF4: 18%Yb, 0.5%Tm and x%Ga<3+> rare earth up-conversion luminescent material is prepared, and the value of x is 0.5-5. The particle size of thematerial is 9-11 nm, the particle size is small, the morphology and size distribution is uniform, and the material can be used as a multi-mode biological imaging contrast agent for UCL imaging, MRI imaging and CT imaging. When Ga<3+> is doped into a matrix, fluorescence emission of Tm<3+> in a luminescence center at the near-infrared wavelength of 800 nm is remarkably enhanced, near-infrared light emission at the near-infrared wavelength of 800 nm has good penetrability to biological tissue, light damage to the biological tissue is small, and fluorescence imaging application of the material in a living body is facilitated. The development of the multimode imaging material has a potential application prospect in the field of biomedicine.