香港空气污染成份的激光光声检测

我们建立了一套激光光声光谱检测装置,以可调谐CO激光器作为光源,成功地检测出香港几个典型交通道口空气中的若干污染气体成份:甲醛、乙醋醛、丙烯醛、乙烯、丙烯、甲苯等有毒气体。     

Electrospray mass spectrometry: application of ion evaporation theory to amino acids

We describe the result of applying the ion evaporation theory to a series of amino acids. The very good correlation (r = 0.98) of the natural logarithms of protonated molecule intensities observed by electrospray with the difference between the hydration free energies of molecules and the gas-phase binding free energies of molecules and protons in amino acids is consistent with the ion evaporation model. It seems that the difference in the protonated molecule intensities of amino acids obtained by electrospray can be explained by a scheme in which protonated molecules in the liquid phase are extracted into the gas phase after a charged droplet is formed.     

Evaluating technical education in a spatially and temporallycompressed world

Engineering and technology educators face potential limitations and problems should they neglect the diversity of social, cultural and political environments in which their students find themselves despite the apparent compression of time and space brought about by technological changes that the difference between individuals is getting smaller. This article looks at the evaluation of engineering and technology education from a social and cultural viewpoint and suggests that the evaluation should aim to be sensitive to local traditions and histories, and to particular wants, needs and fancies     

A fast and effective model for wavelet subband histograms and its application in texture image retrieval.

This paper presents a novel, effective, and efficient characterization of wavelet subbands by bit-plane extractions. Each bit plane is associated with a probability that represents the frequency of 1-bit occurrence, and the concatenation of all the bit-plane probabilities forms our new image signature. Such a signature can be extracted directly from the code-block code-stream, rather than from the de-quantized wavelet coefficients, making our method particularly adaptable for image retrieval in the compression domain such as JPEG2000 format images. Our signatures have smaller storage requirement and lower computational complexity, and yet, experimental results on texture image retrieval show that our proposed signatures are much more cost effective to current state-of-the-art methods including the generalized Gaussian density signatures and histogram signatures.     

Automatic fuzzy ontology generation for semantic help-desk support

Customer service support is an important operation for most multinational manufacturing companies. With the advancement of internet technologies, customer services nowadays are supported through web-based systems. More recently, rapid development of the semantic web and semantic web services has prompted us to develop a semantic help-desk for supporting customer services over the semantic web environment, which is presented in this paper. In particular, a fuzzy formal concept analysis (FCA)-based approach is developed for automatic generation of fuzzy machine service ontology that can deal with uncertain information. The proposed automatic fuzzy ontology generation technique consists of the following steps: fuzzy formal concept analysis, fuzzy conceptual clustering, and ontology generation. As such, the supporting machine services provided by the proposed system will potentially improve customer satisfaction in terms of reducing machine down time and increasing productivity. In this paper, an experiment has also been conducted for performance evaluation. The experimental result shows that the proposed approach has attained good performance in terms of both accuracy and efficiency when the queries are associated with appropriate membership values, and a suitable confident threshold is set.     

Optical emission from LiNbO3(:Fe)/porous Si structures

Using pulsed laser deposition, a layer of LiNbO₃(:Fe) film with a thickness of 180 nm was coated onto porous Si (PS) stored in air for 1 year. A photoluminescence (PL) band enhanced about three times was observed at ∼625 nm with a same peak position as that of the stored PS. It is revealed that a new PL excitation band occurs at ∼363 nm, which is nearly equal to the fundamental optical absorption edge position of LiNbO₃. The X-ray diffraction results disclose that the enhancement of the PL intensity is closely related to formation of a textured LiNbO₃ film. Based on spectral analysis, we attribute the enhanced PL to optical transition in the E′ defect centers localized at the surfaces of PS nanocrystals, whereas the photoexcited carriers mainly come from the coated LiNbO₃ film. This kind of LiNbO₃(:Fe)/PS structures is expected to have important applications in modern ferroelectric optoelectronics.     

Correlation of in vitro susceptibility testing results for amoxicillin-clavulanate and ampicillin-sulbactam using a panel of beta-lactamase-producing Enterobacteriaceae

Laryngospasm occurring after tracheal extubation in children is potentially dangerous. This study uses acupuncture with bloodletting at the Shao Shang (L 11) or Shang Yang (Li 1) acupoints to investigate whether this technique can prevent or treat laryngospasm. Seventy-six patients were randomly divided into two groups. Patients in the acupuncture group (n = 38) were treated with bilateral Shao Shang acupunctures at the end of the operation. Patients in the control group (n = 38) were not. The incidence of laryngospasm in the acupuncture group (5.3%) was less than that in the control group (23.7%) (p < 0.05). If laryngospasm developed, patients were immediately treated with acupuncture at either the Shao Shang or Shang Yang acupoints. As judged by an increase in peripheral oxygen saturation, the laryngospasm was relieved within 1 min of acupuncture in all patients. It is concluded that acupuncture with bloodletting at the Shao Shang acupoint may prevent and treat laryngospasm occurring after tracheal extubation in children.     

Sensitivity tradeoffs for multivariable plants

This paper gives a characterization of the smallest upper bound on the norm of the sensitivity matrix over a frequency interval, with the constraint that the norm remain bounded at all frequencies. The matrix Nevanlinna-Pick interpolation theory is applied to give a necessary and sufficient condition for the existence of a sensitivity matrix meeting the upper bound conditions on thejomega-axis, and the matrix Nevnnlinna-Pick algorithm is used to compute the bounds. A scalar example is also presented to demonstrate the tradeoffs between the bounds inside and outside a given operating frequency band.     

Significance test or effect size?

I describe and question the argument that in psychological research, the significance test should be replaced (or, at least, supplemented) by a more informative index (viz., effect size or statistical power) in the case of theory-corroboration experimentation because it has been made on the basis of some debatable assumptions about the rationale of scientific investigation. The rationale of theory-corroboration experimentation requires nothing more than a binary decision about the relation between two variables. This binary decision supplies the minor premise for the syllogism implicated when a theory is being tested. Some metatheoretical considerations reveal that the magnitude of the effect-size estimate is not a satisfactory alternative to the significance test. (PsycINFO Database Record (c) 2010 APA, all rights reserved)