Micromachined Accelerometers With Optical Interferometric Read-Out and Integrated Electrostatic Actuation

A micromachined accelerometer device structure with diffraction-based optical detection and integrated electrostatic actuation is introduced. The sensor consists of a bulk silicon proof mass electrode that moves vertically with respect to a rigid diffraction grating backplate electrode to provide interferometric detection resolution of the proof-mass displacement when illuminated with coherent light. The sensor architecture includes a monolithically integrated electrostatic actuation port that enables the application of precisely controlled broadband forces to the proof mass while the displacement is simultaneously and independently measured optically. This enables several useful features such as dynamic self-characterization and a variety of force-feedback modalities, including alteration of device dynamics in situ. These features are experimentally demonstrated with sensors that have been optoelectronically integrated into sub-cubic-millimeter volumes using an entirely surface-normal, rigid, and robust embodiment incorporating vertical cavity surface emitting lasers and integrated photodetector arrays. In addition to small form factor and high acceleration resolution, the ability to self-characterize and alter device dynamics in situ may be advantageous. This allows periodic calibration and in situ matching of sensor dynamics among an array of accelerometers or seismometers configured in a network.     

Magnetic compound refractive lens for focusing and polarizing cold neutron beams

Biconcave cylindrical lenses are used to focus beams of x rays or neutrons using the refractive properties of matter. In the case of neutrons, the refractive properties of magnetic induction can similarly focus and simultaneously polarize the neutron beam without the concomitant attenuation of matter. This concept of a magnetic refractive lens was tested using a compound lens consisting of 99 pairs of cylindrical permanent magnets. The assembly successfully focused the intensity of a white beam of cold neutrons of one spin state at the detector, while defocusing the other. This experiment confirmed that a lens of this nature may boost the intensity locally by almost an order of magnitude and create a polarized beam. An estimate of the performance of a more practically dimensioned device suitable for incorporation in reflectometers and slit-geometry small angle scattering instruments is given.     

Spectroscopic Analysis of Southern Pine Treated with Chromater Copper Arsenate. I. X-Ray Photoelectron Spectroscopy (XPS)-17

Abstract

The amount of southern pine lumber treated with chromated copper arsenate annually is considerable, yet the association of this preservative with the wood structure is not clear. The current study was undertaken to elucidate the nature of chemical reactions occurring between the components of the treating solution and the constituents of wood. Small, clear Southern pine samples were treated with six different preservative solutions (Cr; Cr/Cu; Cr/As; CCA-A; CCA-B; CCA-C), at 6.4 and 40 Kg/m³ (0.4 and 2.5 pcf) retentions, and compared to water treated and untreated controls. Samples were dried following treatment and analyzed by X-ray photoelectron spectroscopy (XPS). Evaluation of XPS data indicated that the preservative components reacted with wood, through aromatic and possibly alkene substitution, while oxidation of hydroxyl groups was not detected. The proposed wood/CCA bonding also offers an explanation for differences in hardwood and softwood durability following treatment.     

American Indian and Caucasian students' preferences for counselors: Effects of counselor dress and sex.

Examined the effects of 2 nonverbal cues, the counselor's dress and sex, on students' preferences for counselors. 140 Native Americans from a reservation high school and 226 students from a primarily Caucasian, urban high school rated their preferences for discussing personal, academic, and vocational concerns with a counselor. The independent variables were race and sex of student, and form of dress and sex of counselor. The results of the 2?×?2?×?6?×?2 MANOVA showed that the Ss' preferences for counselors varied with the counselors' sex and dress, the type of concern, and the race of the S. Same-sex preferences for counselors were not influenced by counselor dress. Preference for a counselor of the same sex was strongest for female Native Americans. Cultural and methodological aspects of these results are discussed. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simulation of Thin-Film Damping and Thermal Mechanical Noise Spectra for Advanced Micromachined Microphone Structures

In many micromachined sensors the thin (2-10 thick) air film between a compliant diaphragm and backplate electrode plays a dominant role in shaping both the dynamic and thermal noise characteristics of the device. Silicon microphone structures used in grating-based optical-interference microphones have recently been introduced that employ backplates with minimal area to achieve low damping and low thermal noise levels. Finite-element based modeling procedures based on 2-D discretization of the governing Reynolds equation are ideally suited for studying thin-film dynamics in such structures which utilize relatively complex backplate geometries. In this paper, the dynamic properties of both the diaphragm and thin air film are studied using a modal projection procedure in a commonly used finite element software and the results are used to simulate the dynamic frequency response of the coupled structure to internally generated electrostatic actuation pressure. The model is also extended to simulate thermal mechanical noise spectra of these advanced sensing structures. In all cases simulations are compared with measured data and show excellent agreement - demonstrating 0.8 and 1.8 thermal force and thermal pressure noise levels, respectively, for the 1.5 mm diameter structures under study which have a fundamental diaphragm resonance-limited bandwidth near 20 kHz.     

Is it proper for psychologists to discuss medications with clients?

Situations are analyzed in which psychologists might be asked for information about the efficacy or side effects of pharmacotherapy. The ethics and legality of providing information about physician-prescribed treatments by members of the health care delivery system who are not physicians are considered. Those articles in the psychologist's ethical code bearing on the issue are also discussed. Relevant court cases and statutes in the professions of nursing and pharmacy are examined. For these professions, the findings in relevant cases, coupled with the manner in which recent legislation has been written, suggest that nonphysician members of the health care delivery system can discuss treatments, including medications, prescribed by physicians. The question of a duty of psychologists to discuss medications in the context of obtaining informed consent is raised. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is the reexperience of painful emotion therapeutic?

Recently, a great deal of attention has been focused on the health promoting benefits that can accrue from revisiting painful emotion. The rationales for revisiting painful emotions include those that assume reexperiencing emotion per se can be health-promoting. Another view stipulates that revisiting painful emotion will only yield benefit if there is some recasting/restructuring of the emotional memory. Research pertinent to the various rationales is discussed. Then research on the impact of emotional expression and outcomes studies of therapies designed to enhance emotional experience are reviewed. Good supporting evidence is found for the effectiveness of behavioral exposure therapies where the duration of emotional exposure is carefully controlled, as well as for the salutary impact of talking or writing about trauma by normally functioning individuals. On the other hand, studies evaluating the impact of experiencing and expressing painful emotion in an unstructured fashion with clinical samples suggest that the process can be harmful. Incorporating findings from the behavioral exposure literature and from the Pennebaker writing-about-trauma studies, the case for evoking emotional memories for the purpose of developing new responses is advanced. The dangers of encouraging emotional experience in absence of acquisition of a new response to the emotion-evoking material are discussed.     

Counselor's reputation: An important precounseling variable for adolescents.

The purpose of this research was to determine the precounseling effects of reputational cues on high school students' preferences for counselors and perceptions of the counselor's credibility and interpersonal attractiveness. In two separate but similar experiments, 485 students each saw one of seven experimental conditions presented on videotape. On three videotapes, high school students delivered positive, neutral, or negative reputational cues about a male or a female counselor. Three additional videotapes contained the same positive, neutral, or negative reputational cues and the counselor in a brief counseling session. One videotape featured only the counseling session. Students' preferences for and perceptions of the counselors were significantly different from each other in the positive, neutral, and negative reputational cue conditions. The addition of the counseling session following negative reputational cues resulted in much more positive preferences for and perceptions of the counselors. Reputational cues functioned as an important precounseling variable in that the cues strongly influenced students' preferences and perceptions prior to counseling. (PsycINFO Database Record (c) 2010 APA, all rights reserved)