摘要:
A crystal form I of (S)-4-hydroxy-2-oxo-1-pyrrolidine acetamide, or named (S)-oxiracetam, is provided, which is characterized by a powder x-ray diffraction pattern that exhibits data of d-values versus the relative intensities as: 7.075(M), 5.355(S), 5.092(S), 4.590(M), 4.325(M), 4.259(S), 4.041(VS), 3.808(M), 3.542(M), 3.445(M), 3.393(M), 2.972(M), 2.914(S). A method for preparing a crystal form I of (S)-oxiracetam is also provided, which includes preparing the crude product and crystallizing A use of the crystal form I of (S)-oxiracetam in the manufacture of a medicament for preventing and treating memory dysfunction is also provided. Accordingly, the crystal form I of (S)-oxiracetam prepared by the method has high purity of more than 99.3% based on the percentages of the mass, with better efficacy than (S)-oxiracetam for preventing or treating memory dysfunction. Concerning the way of charging materials, adding inorganic base only a few times is simpler and more beneficial to industrial manufacturing and application.
摘要:
Antenna structures and configurations which incorporate alignment keys and support structures which mate Composite Right and Left Handed (CRLH) metamaterial (MTM) structures formed on two or more substrates.
摘要:
A method for detecting the integrity of a bond of a multi-piece work piece includes capturing a first image of the work piece, stressing the work piece, capturing a stressed image of the work piece, and comparing the first image of the work piece with the stressed image of the work piece to determine the integrity of the bond.
摘要:
A method for assembling a semiconductor package includes a rapid cooling step after post mold curing of an encapsulation material. The rapid cooling step includes blowing chilled, compressed air over the package for about two minutes. The rapid cooling step does not require any clamping pressure be simultaneously applied to the package. The rapid cooling step reduces a temperature of the encapsulation material from a curing temperature to the cooled temperature within a maximum period of less than five minutes. By using rapid cooling, as opposed to cooling the package under a clamping pressure with ambient air, package warpage due to CTE mismatches is prevented.
摘要:
A process for assembling a Chip-On-Lead packaged semiconductor device includes the steps of: mounting and sawing a wafer to provide individual semiconductor dies; performing a first molding operation on a lead frame; depositing epoxy on the lead frame via a screen printing process; attaching one of the singulated dies on the lead frame with the epoxy, where the die attach is done at room temperature; and curing the epoxy in an oven. Throughput improvements may be ascribed to not including a hot die attach process. An optional plasma cleaning step may be performed, which greatly improves wire bonding quality and a second molding quality. In addition, since a first molding operation is performed before the formation of epoxy to avoid the problem of the epoxy hanging in the air, the delamination risk between the epoxy and the die is avoided.
摘要:
A method of forming a pre-molded lead frame having increased stand-offs includes the steps of attaching a first tape to a first side of the lead frame and a second tape to a second side of the lead frame. The taped lead frame is placed in a mold and a first flow of mold compound is initiated. The first flow of the mold compound fills a space between the first tape and an upper mold chase of the mold. A second flow of the mold compound then is initiated. The second flow of the mold compound fills the spaces between a die pad and leads of the lead frame. The first and second tapes then are removed from the lead frame. Improved stand-offs are provided because the first tape was depressed by the first flow of the mold compound.
摘要:
In a method of packaging a semiconductor IC, a tape is attached to a back surface of a lead frame array, and the lead frame array is held between an upper mold chase and a lower mold chase of a mold, with the back surface of the lead frame array upward. The upper and lower mold chases form an upper cavity and a lower cavity with respect to the lead frame array respectively. A mold compound is injected into the upper and lower cavities respectively. With respect to clearances between leads, between die pads and/or between the leads and the die pads, the mold compound injected into the upper cavity covers the portion of the tape over the clearances before the mold compound injected into the lower cavity fills the clearances, so that the tape is depressed. After curing the mold compound, removing the mold and de-taping, the mold compound filled in the clearances is recessed inward from the back surface, which increases the solderability in the subsequent surface mount process and decreases the possibility of the occurrence of lead short-circuits.
摘要:
When visualizing the stress distribution of natural bone, synthetic bone, or a member attached to either thereof without omitted points, in order to measure accurately in a variety of modes using an inexpensive system, a mechanoluminescence material thin film 6 is formed in advance on a bone material peripheral surface 5 in an appropriate area thereof including the portion where an insertion support portion 4 of an artificial hip prosthesis 2 is inserted into a hollow inside 3 of a damaged femur 1 or a synthetic bone simulating the damaged femur. The mechanoluminescence material thin film 6 portion is photographed over its entire circumference with an IICCD camera 7 from the external peripheral side thereof as or after the artificial hip prosthesis 2 is inserted. The obtained image is fed to a computer 11 to obtain a luminescence image 8. The computer 11 outputs the intensities of the received light in the form of an image as is, so that the luminescence image 8 can be obtained easily. Particularly, the data about the intensities of the received light can be used as stress/strain data virtually as is. Such method is also suitable for dynamic analysis.
摘要:
A stress-induced light emitting composite material according to the present invention contains at least stress-induced light emitting inorganic particles, which emit light at application of a mechanical effect thereon and a polymer material. The stress-induced light emitting inorganic particles are not more than a wavelength of visible light in particle diameter and surface-treated. With this arrangement, the stress-induced light emitting composite material becomes transparent in a visible light range. Moreover the surface treatment of the stress-induced light emitting inorganic particles give water resistance to the stress-induced light emitting inorganic particles.
摘要:
A mechanoluminescence material comprising a matrix of composite metal oxide containing strontium and aluminum, represented by the general formula SrM1Al6O11 (wherein M1 is an alkaline earth metal) or SrM2Al3O7 (wherein M2 is a rare earth metal), and further comprising, as luminescence centers, a metal selected from among rare earth metals and transition metals capable of emitting light when a carrier having been excited by mechanical energy returns to its ground state.
摘要翻译:一种机械发光材料,其包含由通式SrM 1 Al 6 O 11表示的含有锶和铝的复合金属氧化物的基质(其中M 1是一种碱土金属)或SrM 2 O 3 N 7 O 7(其中M < / SUP>是稀土金属),并且还包含作为发光中心的金属,当通过机械能激发的载体返回到其基态时,能够发光的稀土金属和过渡金属中的金属。