A Low Power 5.8GHz Fully Integrated CMOS LNA for Wireless Applications

A low power 5.8 GHz fully integrated CMOS low noise amplifier (LNA) with on chip spiral inductors for wireless applications is designed based on TSMC 0.18 µm technology in this paper. The cascode structure and power-constrained simultaneous noise and input matching technique are adopted to achieve low noise, low power and high gain characteristics. The proposed LNA exhibit a state of the art performance consuming only 6.4mW from a 1.8V power supply. The simulation results show that it has a noise figure (NF) only 0.972 dB, which is perfectly close to NFmin while maintaining the other performances. The proposed LNA also has an input 1-dB compression point (IP1dB) of-21.22 dBm, a power gain of 17.04 dB, and good input and output reflection coefficients, which indicate that the proposed LNA topology is very suitable for the implementation of narrowband LNAs in 802.11a wireless applications

Human motion analysis and measurement techniques: current application and developing trend

Human motion analysis and measurement technology have been widely used in the fields of medical treatment, sports science, and rehabilitation. In clinical practice, motion analysis has been applied in the diagnosis and individualized treatment planning of various musculoskeletal diseases, and it is also an important objective scientific method to evaluate the therapeutic effect and the effectiveness of medical equipment. This study aimed to introduce the common modern motion capture measurement technology and equipment, the clinical application and limitations of motion analysis, and the possible development trend of motion analysis measuring techniques in the future. Motion analysis and measurement systems and medical image measurement and analysis technology have made landmark improvements over the past few decades in terms of orthopaedical biomechanics. Nevertheless, limitations still exist, both subjective and objective. All these drawbacks have promoted the exploration of the integrated methods that have now been widely used in motion analysis. The results of the case study about the subject-specific finite element modeling of the foot and sports shoe complex have also shown great consistency. Nevertheless, several possible future directions for motion analysis measuring techniques still exist. In the future, the progress of motion analysis and measurement methods will simultaneously drive the progress of orthopedics, rehabilitation, precision personalized medicine, and medical engineering

CFD Simulations to Study Parameters Affecting Gas Explosion Venting in Compressor Compartments

In this work, a series of vented explosions in a typical compressor compartment are simulated using FLACS code to analyze the explosion venting characteristics. The effects of relevant parameters on the pressure peaks (i.e., overpressure and negative pressure) are also numerically investigated, including vent area ratio of the compressor compartment, vent activation pressure, mass per unit area of vent panels, and volume blockage ratio of obstacles. In addition, the orthogonal experiment design and improved grey relational analysis are implemented to evaluate the impact degree of these relevant parameters. The results show that the pressure peaks decrease with the increase of vent area ratio. There is an approximately linearly increasing relationship between the pressure peaks and the vent activation pressure. The pressure peaks increase with the mass per unit area of vent panels. The pressure peaks increase with the volume blockage ratio of obstacles. Based on the grey relational grade values, the effects of these relevant parameters on the overpressure peak are ranked as follows: volume blockage ratio of obstacles > vent activation pressure > vent area ratio > mass per unit area of vent panels. These achievements provide effective guidance for the venting safety design of gas compressor compartments

Shock-Heated Gas in the Large Scale Structure of the Universe

Cosmological shock waves play a major role in heating baryonic gas in the large scale structure of the universe. In this contribution we study the shock-heated gas in connection with shocks themselves. The distributions of shock speed and temperature of shock-hated gas both should reflect the depth of gravitational potential of associated nonlinear structures, so their morphology. From their distributions we find, in addition to hot gas in and around clusters/groups and warm-hot intergalactic medium (WHIM) with T=10^5-10^7 K mostly in filaments, there is a significant amount of low temperature WHIM with T < 10^5 K distributed mostly as sheet-like structures. Not only the WHIM with T=10^5-10^7 K but also the WHIM with T < 10^5 K make up a significant fraction of gas mass, implying the low temperature WHIM could be important in resolving the missing baryon problem. The shock-heated gas in filaments and sheets are manifested best through emissions and absorptions in soft X-ray and far UV. We confirm that the WHIM with T=10^5-10^7 K makes significant contributions to the soft X-ray background, absorptions of highly ionized species such as OVII and OVIII in AGN spectra, and line emissions from OVII and OVIII ions, as pointed by previous studies. However, the WHIM with T < 10^5 K is the major contributor to absorptions of lower ionized species such as OV and OVI, because these photo-ionized ions are most abundant in sheets of low density and temperature. (abridged)Comment: To appear in ApJ. 8 figures with 3 in jpg. Postscript file with full resolution figures - http://canopus.chungnam.ac.kr/ryu/kangetal.zi

1-(2-Hydr­oxy-4,5-dimeth­oxyphen­yl)propan-1-one

In the title compound, C11H14O4, isolated from the stems of Trigonostemon xyphophylloides, an intra­molecular O—H⋯O hydrogen bond helps to establish an essentially planar conformation for the mol­ecule (r.m.s. deviation = 0.044 Å)

2-Hydr­oxy-1-methoxyxanthen-9-one monohydrate

In the title compound, C14H10O4·H2O, isolated from the roots of Calophyllum membranaceum, the xanthene ring system is almost planar (r.m.s. deviation = 0.008 Å). In the crystal structure, inter­molecular O—H⋯O and O—H⋯(O,O) hydrogen bonds connect the mol­ecules

2-Hy­droxy-3-nitro­benzaldehyde

The title compound, C7H5NO4, isolated from the leaves of Actephila merrilliana, is essentially planar (r.m.s. deviation = 0.026 Å). The conformation is supported by an intra­molecular O—H⋯O hydrogen bond, which generates an S(6) ring. In the crystal, C—H⋯O inter­actions and aromatic π–π stacking [centroid–centroid distance = 3.754 (4) Å] help to establish the packing

Several Treatments on Nonconforming Element Failed in the Strict Patch Test

For nonconforming finite elements, it has been proved that the models whose convergence is controlled only by the weak form of patch tests will exhibit much better performance in complicated stress states than those which can pass the strict patch tests. However, just because the former cannot provide the exact solutions for the patch tests of constant stress states with a very coarse mesh (strict patch test), their usability is doubted by many researchers. In this paper, the non-conforming plane 4-node membrane element AGQ6-I, which was formulated by the quadrilateral area coordinate method and cannot pass the strict patch tests, was modified by three different techniques, including the special numerical integration scheme, the constant stress multiplier method, and the orthogonal condition of energy. Three resulting new elements, denoted by AGQ6M-I, AGQ6M-II, and AGQ6M, can pass the strict patch test. And among them, element AGQ6M is the best one. The original model AGQ6-I and the new model AGQ6M can be treated as the replacements of the well-known models Q6 and QM6, respectively