A3复印 精打细算—佳能iR2320J黑白A3数码复合机

佳能iR2320J黑白A3数码复印机与之前的iR2318L／iR2320L／iR2320N／iR2420D属于同一产品系列。作为同系列中定位最低的一款，佳能iR2320J只支持复印功能，因此主要用于类似售楼大厅，办证大厅、公司前台等开放性场合。如果需要功能更丰富的产品，可以根据自身情况选择同系列其它型号（功能差异见右表）。     

浅谈易引起电气火灾的接地故障

本文对民用建筑物低压配电系统中易引起电气火灾的接地故障进行分析,分别从接地故障的危害、现有接地故障的预防措施及单纯使用剩余电流保护器检测接地故障存在的问题等进行论述,指出了接地故障检测系统的发展方向。     

让我们一起倡导DIY精神—专访华硕中国业务群副总经理王俊人

“同质化日趋严重，创新力光芒不再，在面对DIY市场上不少厂商凸显的这些问题时，王俊人不仅首次剖析全民超频背后的深意，还提出DIY精神需要玩家、媒体和厂商一起来倡导……”     

中国电源管理IC市场不惧芯片产业放缓

据iSupPli公司，尽管预计2009年中国电源管理IC市场营业额跌幅将达到两位数，但预计下半年将出现反弹，并在未来几年以健康的速度增长。     

半岛听“风”-巴瑞洛切之屋

巴瑞洛切市是阿根廷巴塔哥尼亚省最美丽的小城之一.这里山水相依,植被丰富,景色旖旎,纳韦尔瓦安湖占地面积超过500km^2,一汪湖水碧如蓝,是当地居民和游客心驰神往,流连忘返的自然殿堂．     

用长期试验数据来选择连接器用工程塑料

许多美国军用规范中规定连接器的绝缘体材料采用邻苯二甲酸二丙烯塑料(DAP)。这是由于它在各种恶劣的环境中能保持其电性能及有优越的尺寸稳定性。本文通过长期试验得出的数据说明了上述问题。它可供连接器的研究、设计和使用者参考。     

Treatment of arsenic-containing solutions using chitosan derivatives: uptake mechanism and sorption performances

Modified chitosan gel beads, which had been prepared by the molybdate adsorption and coagulation (in the presence of molybdate) methods, were tested for As(III) and As(V) removal from dilute solutions (in the range 5-20 mg As L-1). The sorbent is very efficient at removing As(V) from acid solutions (optimum pH close to pH 2-3), whereas the sorption capacities are significantly lower for As(III) uptake (230 mg As(V) g-1 Mo, 70 mg As(III) g-1 Mo, respectively). Since the sorption proceeds in acidic solutions with a partial release of molybdate and with residual concentrations (ca. 500 micrograms As L-1) above the regulations for drinking water, the process appears to be directed to the treatment of industrial effluents or as a pre-concentration process. The mechanism of As(V) sorption is related to the ability of molybdate ions to complex As(V) ions in acid solutions. The uptake mechanism was confirmed by XPS analysis and desorption studies. In the case of As(III) sorption the mechanism of uptake is not identified since no complex has been cited in the literature regarding As(III) binding to Mo (VI), which was also identified by XPS analysis as the sorption site. As(V) sorption is not influenced by the presence of co-ions, with the exception of phosphate anions at low concentration, and silicate at high relative concentration. Arsenic desorption can be performed using phosphoric acid solutions.     

Elucidating a biological role for chromium at a molecular level

Chromium is an essential trace element for mammals and is required for maintenance of proper carbohydrate and lipid metabolism. However, elucidating its function at a molecular level has proved to be problematic. Recent research has revealed that the chromium-binding oligopeptide chromodulin may play a unique role in the autoamplification of insulin signaling. Attempts to develop chromium-containing nutritional supplements and therapeutics are described.     

Learning eigenfunctions links spectral embedding and kernel PCA

In this letter, we show a direct relation between spectral embedding methods and kernel principal components analysis and how both are special cases of a more general learning problem: learning the principal eigenfunctions of an operator defined from a kernel and the unknown data-generating density. Whereas spectral embedding methods provided only coordinates for the training points, the analysis justifies a simple extension to out-of-sample examples (the Nystr?m formula) for multidimensional scaling (MDS), spectral clustering, Laplacian eigenmaps, locally linear embedding (LLE), and Isomap. The analysis provides, for all such spectral embedding methods, the definition of a loss function, whose empirical average is minimized by the traditional algorithms. The asymptotic expected value of that loss defines a generalization performance and clarifies what these algorithms are trying to learn. Experiments with LLE, Isomap, spectral clustering, and MDS show that this out-of-sample embedding formula generalizes well, with a level of error comparable to the effect of small perturbations of the training set on the embedding.