This research aims to develop a novel foot sole mechanism which utilizes the jamming transition effect of granular material enclosed in an air tight bag, for use by bipedal robot walking on uneven ground. The mechanism is designed to make the foot sole be soft and compliant to adapt to the surface of an uneven terrain, and be stiff when the robot is in the support phase of the walking gait. The stiffness-variable property of the mechanism according to the internal air pressure of the bag is investigated. To measure the tilting stability when center of pressure is moved across the proposed foot sole, a test using an inverted pendulum apparatus had been carried out and compared to when using a rigid flat foot sole.
A gold-catalyzed N,O-acetal formation
was established to construct an amide/carbamate-linked N,O-acetal substructure with bulky alcohols. The
acyliminium cation species generated from o-alkynylbenzoic
acid ester in the presence of a gold catalyst is highly reactive and
underwent nucleophilic attack of various bulky alcohols and phenols
at room temperature under neutral conditions, leading to the corresponding N,O-acetals in yields of 34–89%
with good functional group tolerance.
The
stereoselective and short-step synthesis of N-protected allo-carnosadine, ent-carnosadine, and
carnosadine lactam was accomplished from a common
cyclopropane intermediate. The inter-intramolecular double alkylation
of diethyl malonate with an optically active 2-methylaziridine derivative
gave the key cyclopropane in excellent yield and optical purity. The
following monohydrolysis of the diester moiety using different reaction
conditions provided both diastereomers of monoacids, which were converted
to three carnosadine derivatives in 5–6 steps from the common
diester.
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