polyethylene glycol was easily grafted to silica gel and used as a solid–liquid phase transfer catalyst in the reduction of aromatic nitro compounds. this silica-grafted polyethylene glycol is proved to be an efficient heterogeneous catalyst in the reduction of nitroarenes to the corresponding aromatic amines with zinc powder in water. the reduction reactions proceeded efficiently with excellen...

background and purpose: in a recent century, the amount of construction waste has increased significantly. although the building industry has a considerable role in the development of a society, it is regarded as an environmentally destructive. source reduction is the highest goal in the waste management hierarchy and is in priority. it also has economic benefits by reducing costs associated wi...

Phase noise in mutually synchronized oscillator systems is analyzed for arbitrary coupling and injection-locking topologies, neglecting amplitude noise, and amplitude modulation (AM) to phase modulation (PM) conversion. When the coupling phase is chosen properly (depending on the oscillator model), the near-carrier phase noise is reduced to 1=N that of a single oscillator, provided the coupling...

The noise in reconstructed slices of X-ray Computed Tomography (CT) is of unknown distribution, non-stationary, oriented and difficult to distinguish from main structural information. This requires the development of special post-processing methods based on the local statistical evaluation of the noise component. This paper presents an adaptive method of reducing noise in CT images employing th...

In this paper, a method is proposed to improve the noise performance of the delay and add direct sequence (DADS) modulation scheme by modifying the structure of the reference signal and the demodulation algorithm. It is shown that noise reduction by averaging can enhance the bit error rate (BER) performance of DADS considerably. As the number of noisy chips exploited at the receiver increases, ...

Introduction Echo-planar imaging (EPI) is a group of fast data acquisition methods commonly used in fMRI studies. It acquires multiple image lines in k-space after a single excitation, which leads to a very short scan time. A well-known problem with EPI is that it is more sensitive to distortions due to the used encoding scheme. Source of distortion is inhomogeneity in the static B0 field that ...

A methodology for treating the semiconductor laser as a current-controlled oscillator in an optical phase-lock loop is presented. The formalism is applied to phase demodulation of optical beams, reduction of phase noise by self-homodyning, and phase locking of a semiconductor laser array.

The resistance of the improved moving objects detection algorithm to various types of additive and multiplicative noise is discussed. The algorithm’s first phase contains the noise suppression filter based on spatiotemporal blocks including dimensionality reduction technique for a compact scalar representation of each block, and the second phase consists of the moving object detection algorithm...

Recently low-voltage and low-noise analog circuits with sub100nm CMOS devices are strongly demanded for implementing mobile digital multimedia and wireless systems. Reduction of supply voltage makes it difficult to attain a signal voltage swing, and device deviation causes large DC offset voltage and 1/f noise. This paper describes noise reduction technique for CMOS analog and RF circuits opera...