Publications

ISSN:1029-7006

This paper introduces a learning-based low-level controller for quadcopters, which adaptively controls quadcopters with significant variations in mass, size, and actuator capabilities. Our approach leverages a combination of imitation learning and reinforcement learning, creating a fast-adapting and general control framework for quadcopters that eliminates the need for precise model estimation or manual tuning. The controller estimates a latent representation of the vehicle's system parameters from sensor-action history, enabling it to adapt swiftly to diverse dynamics. Extensive evaluations in simulation demonstrate the controller's ability to generalize to unseen quadcopter parameters, with an adaptation range up to 16 times broader than the training set. In real-world tests, the controller is successfully deployed on quadcopters with mass differences of 3.7 times and propeller constants varying by more than 100 times, while also showing rapid adaptation to disturbances such as off-center payloads and motor failures. These results highlight the potential of our controller in extreme adaptation to simplify the design process and enhance the reliability of autonomous drone operations in unpredictable environments. The video and code are at: https://github.com/muellerlab/xadapt_ctrl

Adv. Mater. 2014, 25, 4313–4319 In the above article the following citations have to be added on page 2, line 1 after “TI” in the following sentence:

Abstract The borylation of C−H bonds catalyzed by transition metals has been investigated extensively in the past two decades, but no iridium‐catalyzed enantioselective borylation of C−H bonds has been reported. We report a set of iridium‐catalyzed enantioselective borylations of aromatic C−H bonds. This reaction relies on a set of newly developed chiral quinolyl oxazoline ligands. This process proceeds under mild conditions with good to excellent enantioselectivity, and the borylated products can be converted to enantioenriched derivatives containing new C−O, C−C, C−Cl, or C−Br bonds.

UCLA has spent the last 15 years pioneering the thorough development of possibly the most comprehensive graduate-level MEMS curriculum in the world, which is jointly offered by the EE and MAE departments.Students from EE and MAE are admitted directly into a formal MEMS major field, complete a set of 4 core courses, take a MEMS preliminary exam, complete the rest of their course work by selecting from MEMS and non-MEMS electives, take a qualifying exam, and complete their theses (M.S. and/or Ph.D.).To date at least 9 specifically MEMS/nano-related graduate-level elective courses have been developed and are presently being offered.To date well over 100 graduate students have completed or are completing this unique program.Those that have graduated have gone on to be productive faculty at U.S. and international academic institutions, engineers at MEMS and non-MEMS companies, and have started a number of MEMS start-up companies.

We demonstrate, for the first time, the trapping and manipulation of individual Si nanowires by light-induced dielectrophoresis, or optoelectronic tweezers (OET). Trapping of single Si nanowires, with a diameter of 100 nm and length of 5 μm, is reported using OET with an optical power density of 100 W/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> . We show that OET can separate two adjacent Si nanowires and transport a single nanowire at a speed of 135 μm/s. Array patterns of Si nanowires have also been demonstrated.

Resource constraints have become critical for the Li-ion industry. Spinel LiMn 2 O 4 presents a cheaper, more sustainable alternative to traditional layered Li-ion cathodes, but its capacity is constrained by a two-phase transition at ~3V associated with a large, inhomogeneous volume change that leads to particle cracking and poor cycling stability. In contrast, the partially disordered spinels (PDS) have more sloping, solid-solution-like behavior, resulting in better rate capability and more homogeneous volume change. In this talk, we demonstrate that PDS achieves this by introducing cation disorder, which can shrink, and even fully remove, the two-phase region. By analyzing samples from cluster expansion-based Monte Carlo simulations, we identify the mechanisms that increase Li solubility in the LiMn 2 O 4 phase and lead to this shortened ~3V plateau. These results provide guidance on the optimal level of disorder in spinels to achieve both solid-solution behavior and good Li mobility and also highlight more generally how disorder can be utilized to reduce the effects of problematic phase transformations in ordered frameworks.

Abstract Previous studies have demonstrated both energy restriction (ER) and higher protein (HP), lower carbohydrate (LC) diets downregulate hepatic de novo lipogenesis. Little is known about the independent and combined impact of ER and HP/LC diets on tissue‐specific lipid kinetics in leptin receptor‐deficient, obese rodents. This study investigated the effects of ER and dietary macronutrient content on body composition; hepatic, subcutaneous adipose tissue (SAT), and visceral AT (VAT) lipid metabolic flux ( 2 H 2 O‐labeling); and blood and liver measures of cardiometabolic health in six‐week‐old female obese Zucker rats (Lepr fa+/fa+ ). Animals were randomized to a 10‐week feeding intervention: ad libitum (AL)‐HC/LP (76% carbohydrate/15% protein), AL‐HP/LC (35% protein/56% carbohydrate), ER‐HC/LP, or ER‐HP/LC. ER groups consumed 60% of the feed consumed by AL. AL gained more fat mass than ER (P‐energy = 0.012) and HP/LC gained more fat mass than HC/LP (P‐diet = 0.025). Hepatic triglyceride (TG) concentrations (P‐interaction = 0.0091) and absolute hepatic TG synthesis (P‐interaction = 0.012) were lower in ER‐HP/LC versus ER‐HC/LP. ER had increased hepatic, SAT, and VAT de novo cholesterol fractional synthesis, absolute hepatic cholesterol synthesis, and serum cholesterol (P‐energy≤0.0035). A HP/LC diet, independent of energy intake, led to greater gains in fat mass. A HP/LC diet, in the context of ER, led to reductions in absolute hepatic TG synthesis and TG content. However, ER worsened cholesterol metabolism. Increased adipose tissue TG retention with the HP/LC diet may reflect improved lipid storage capacity and be beneficial in this genetic model of obesity.