Large deflection angle fan-out element based on dislocated grating array

We study the possibility of designing and fabricating a fan-out element based on a computer-generated hologram (CGH) which is capable of providing a large deflection angle without using excessively small CGH cells. The recent development of CGHs using dislocated grating arrays was employed to design the fan-out element. Experimental results show that a deflection angle of 41° was achieved using a CGH cell size of 10 μm×10 μm and an operating optical wavelength of 0.98 μm. Further experimental results and theoretical analysis are also presented in order to investigate the characteristics of this type of fan-out element.     

Model for transient n-heptane droplet ignition at elevated pressure

Journal of Thermal Analysis and Calorimetry - The present work deals with transient droplet evaporation and ignition process of an isolated n-heptane droplet at high pressure. The...     

Total Synthesis of (+)-6-epi-Ophiobolin A

The ophiobolin sesterterpenes are notable plant pathogens which have recently elicited significant chemical and biological attention because of their intriguing carbogenic frameworks, reactive functionalities, and emerging anticancer profiles. Reported herein is a total synthesis of (+)-6-epi-ophiobolin A in 14 steps, a task which addresses construction of the synthetically challenging spirocyclic tetrahydrofuran motif as well as several other key stereochemical problems. This work demonstrates a streamlined synthetic platform to complex ophiobolins leveraging disparate termination modes of a radical polycyclization cascade for divergent elaboration and functionalization.     

A Power-Controllable Semiconductor Fiber Ring Laser and its Applications

A stable and power controllable laser with larger than 17-dB output power range is presented. Based on this device, a novel optical amplifier with the power transit immune behaviors has been demonstrated.     

Effective tuning of the arene and alkanesulfinamides for highly enantioselective synthesis of (S)-4-chlorophenylphenylmethylamine, a key intermediate for antihistamic (S)-cetirizine

High diastereoselectivity (>94%) has been achieved in the phenylMgBr addition process to chlorophenyl aldimine derived from the new and sterically hindered triisopropylbenzene sulfinamide (TIPBSA) in the synthesis of a key intermediate of (S)-Cetirizine. Surprisingly, under the same reaction conditions, toluenesulfinamide derived chlorophenyl aldimine provided only 10% ee.     

57Mössbauer studies in the double transition Ce(Fe1−xCox)2 alloys

The reported double transition in the series Ce(Fe_1–xCo_x)₂ for x<0.3 has been shown to be due to spin reorientation from Mossbauer measurements at⁵⁷Fe. It is suggested that the competing interactions with randomly substitution of Fe by Co atoms causes a quasi random freezing which results in abrupt loss of magnetization.     

Geometry effect on the nonlinear magnetic response of YBa2Cu3O7−y

Results are presented for study of nonlinear magnetization of a sintered YBa₂Cu₃O_7−y pellet of different thickness of a sample subjected to very low magnetic field. On cooling the sample belowT _c in zero field a change, in the oscillatory structure of harmonics in increasing dc field is observed in very low ac magnetic field. The effect of finiteness of the sample on the oscillatory structure and on the hysteresis of harmonics is also studied. The results are explained qualitatively.     

Polymers in Waveguide Packaging

Polymers were successfully used in the packaging of waveguide-based photonic components in the area of fiber-to-waveguide coupling, waveguide die attachment, strain relief, and waveguide encapsulation. The application results of these polymers were described in this paper.     

Combining chiral elements: a novel approach to asymmetric phase-transfer catalyst design

A new dicationic asymmetric phase-transfer catalyst, designed by combining chiral elements, is described. Catalytic testing using standard glycine imino ester alkylations shows good yields and moderate enantioselectivities.     

Dynamic NMR investigation of two new interconvertible diasteriomeric epimers of natural 2-benzyl-2-hydroxybenzofuranone derivative from Pterocarpus marsupium

The first example of a pair of interconvertible diastereomeric epimers 2α/2β-hydroxy-2-p-hydroxybenzyl-3(2H)-benzofuranone-7-C-β-d-glucopyranoside isolated from the heartwood of Pterocarpus marsupium is reported. The predominance of 1a over 1b was supported by dynamic exchange rates and activation parameters obtained from NMR studies. The mechanism of this unique phenomenon is thought to be operative by the formation of diketone as suggested by deuterium exchange.