Selective and potent nicotinic agonists of the formula: ##STR1## including pharmaceutically-acceptable salts or prodrugs thereof, useful in the treatment of dementias, attentional hyperactivity disorder, anxiety associated with cognitive impairment, or substance abuse withdrawal characterized by decreased cholinergic function.

Dementia has been widely recognized as a very serious health problem. Alzheimer's Disease, which has been identified by the National Institutes of Aging as accounting for more than 50% of dementia in the elderly is the fourth or fifth leading cause of death in Americans over 65 years of age. Four million Americans, 40% of Americans over age 85 (the fastest growing segment of the U.S. population), have Alzheimer's Disease. Twenty-five percent of all patients with Parkinson's Disease also suffer from Alzheimer's Disease-like dementia. And in about 15% of patients with dementia, Alzheimer's Disease and multi-infarct dementia coexist. The third most common cause of dementia, after Alzheimer's Disease and vascular dementia, is cognitive impairment due to organic brain disease related directly to alcoholism, which occurs in about 10% of alcoholics.
The precise molecular lesion(s) that contribute to the morphological and functional deficits associated with dementia is unclear despite intensive research efforts over the last decade. However, the most consistent abnormality for Alzheimer's Disease, as well as for vascular dementia and cognitive impairment due to organic brain disease related directly to alcoholism, is the degeneration of the cholinergic system arising from the basal forebrain (BF) to both the cortex and hippocampus (Bigl et al., in: Brain Cholinergic Systems, M. Steriade and D. Biesold, eds., Oxford University Press, Oxford, 1990, pp. 364-386). In particular, neurochemical evidence from the brains of patients afflicted with Alzheimer's Disease has revealed reliable decreases in markers of cholinergic neuronal function (Perry et al., Br. Med. J., 1978, 2:1457; Reisine et al., Brain Res., 1978, 159:477; Coyle et al., Science, 1983, 219:1184; McGeer et al., Neurology, 1984, 34:741). While there are a number of other neurotransmitter systems affected by Alzheimer's Disease (Davies, Med. Res. Rev., 1983, 3:221), the relative occurrence of such abnormalities is less consistent or the effect is less profound than the decreases in these cholinergic neuronal function markers. More specifically, substantial reductions (30-50%) in nicotinic cholinergic receptors have been consistently reported in the brains of patients with Alzheimer's Disease and Parkinson's Disease (Keller et al., Brain Res., 1987, 436:62; Whitehouse et al., Neurol., 1988, 38:720), whereas changes in muscarinic cholinergic receptors are less remarkable and more dependent on receptor subtype.
However, degeneration of the cholinergic neurotransmitter system is not limited to individuals suffering from dementia. It has also been seen in healthy aged adults and rats. Decreases in cholinergic markers in the basal forebrain, decreases in cortical activities of the biosynthetic and degradative enzymes for acetylcholine, decreases in the ability to release acetylcholine from tissue slices, and decreases in numbers of cortical nicotinic receptors have all been reported in otherwise healthy aged individuals (for review, see Giacobini, J. Neurosci. Res. 1990, 27:548). Moreover, for those cholinergic neurons that remain, aging may cause a decrease in the temporal fidelity of existing impulse flow from the basal forebrain to the cortex (Aston-Jones et al., Brain Res., 1985, 325:271). Consistent with these findings are pharmacological studies suggesting that cholinergic mechanisms are, at least in part, responsible for the memory disturbances in aged animals and humans not suffering from Alzheimer's Disease (Drachman and Leavitt, Arch. Neurol., 1974, 30:113; Bartus et al., Science, 1982, 217:408).
Other clinical correlates associated with the neurodegenerative process of Alzheimer's Disease are decreases in regional cerebral blood flow and cerebral glucose utilization, which largely parallel the areas where cholinergic deficits occur (Ingvar and Risberg, Exp. Brain Res., 1962, 3:195; Ingvar et al., Aging: Alzheimer's Disease, Senile Dementia and Related Disorders, Vol. 7, R. Katzman, R. D. Terry, and K. L. Bick, eds., Raven Press, 1978, p. 203; Dastur, J. Cerebral Blood Flow & Metabol., 1985, 5:1). In fact, it has been suggested that routine measurement of cerebral blood flow may be a useful procedure in evaluating patients suspected of having dementia, and of Alzheimer's Disease in particular.
Conflicting reports exist regarding the effect of aging on resting cerebral blood flow and cerebral glucose utilization in "normal healthy" aged humans (Dastur, J. Cerebral Blood Flow & Metabol., 1985, 5:1,) and rats (Smith et al., Brain, 1980, 103:351; Buchweitz-Milton and Weiss, Neurobiol. Aging, 1987, 8:55). Although decreases in cerebral blood flow and cerebral glucose utilization are generally reported in aged populations, it has been suggested that these decreases are secondary to other ongoing cerebral dysfunctions. Nonetheless, deficiencies in metabolic and cerebrovascular responses to pharmacologic and physiologic perturbation are consistently reported. Of particular interest is the recent finding in rats that increases in cerebral blood flow elicited by electrical stimulation of the basal forebrain shows age-related impairments (Linville and Arneric, Soc. Neurosci. Abstract., 1989, 15:175). Indeed, studies that compare the degree of learning impairment with the degree of reduced cortical cerebral blood flow in aged rats show a good correlation (Berman et al., Neurobiol. Aging, 1988, 9:691).
Chronic alcoholism, more particularly, the resultant organic brain disease, like Alzheimer's Disease and normal aging, is also characterized by diffuse reductions in cortical cerebral blood flow in those brain regions where cholinergic neurons arise (basal forebrain) and project to (cerebral cortex) (Lofti & Meyer, Cerebrovasc. and Brain Metab. Rev., 1989, 1:2). Moreover, of all the neurotransmitter systems studied, the neurotoxic effects of alcohol on the cholinergic system are thought to be the most important.
Recent clinical evidence suggests that the characteristic perfusion abnormality observed in Alzheimer's Disease patients reflects regional nicotinic cholinergic deficits (Prohovnik, Neurobiol. Aging, 1990, 11:262). In particular, mecamylamine, a centrally-acting nicotinic receptor antagonist, reduces resting cortical perfusion in the parietotemporal cortex of humans, the area of the cortex most consistently found to be impaired in functional brain imaging of Alzheimer's Disease patients. In agreement with this finding, regulation of cerebral blood flow in the frontoparietal cortex, governed by the basal forebrain, is also dependent upon nicotinic mechanisms in the rat (Arneric, J. Cerebral Blood Flow & Metabol., 1989, 9(Suppl. 1): S502).
Intuitively, regardless of specific etiologic process, therapies directed towards enhancing cognitive processing would be contingent upon maintaining a well-regulated balance between adequate cerebral blood flow, cerebral glucose utilization and cholinergic neurotransmission arising from the basal forebrain.
Pilot clinical studies suggest that nicotine may be useful for the acute treatment of deficits in attention and information processing associated with Alzheimer's Disease (Sahakian et al., Brit. J. Psych., 1989, 154:797; Newhouse et al., Psychopharmacol., 1988, 95:171). Anecdotal evidence suggests a negative correlation between Alzheimer's Disease and smoking, and both acutely and chronically-administered nicotine enhances cognitive function in rats (Levin et al., Behav. Neural Biol., 1990, 53:269), an effect that is preserved in aged animals (Cregan et al., Soc. Neurosci. Abstract, 1989, 15:295). These clinical findings are supported by animal studies demonstrating a neurogenerative/neuroprotective action of chronically-administered nicotine on both neuronal and vascular functions following hemitransection or MPTP-induced destruction of the nigro-striatal dopamine system (Janson et al., Prog. Brain Res., 1989, 79:257; Owman et al., Prog. Brain Res., 1989, 79:267). Interestingly, in contrast to the classical down-regulation of receptors typically seen with receptor agonists, chronic nicotine administration up-regulates (50-100%) the number of receptors without affecting affinity (Benwell et al., J. Neurochem., 1988, 50:1243). This effect occurs both in humans and smaller animals such as rats (Lapchack et al., J. Neurochem., 1989, 52:483).
Existing cholinergic agonists, however, are therapeutically sub-optimal. This is due to unfavorable pharmacokinetics (e.g., with arecoline and nicotine), poor potency and lack of selectivity (e.g., with RS-86), poor CNS penetration (e.g., with carbachol) or poor oral bioavailability (e.g., with nicotine). RS-86, for example, has similar affinity for cholinergic receptors located in the heart and cortical tissues and is a full agonist at cardiac receptors, whereas it is only a partial agonist at cortical receptors (S. B. Freedman, British Journal of Pharmacology, 1986, 87: 29P). In addition, known agents have many unwanted central agonist actions, including hypothermia, hypolocomotion and tremor and peripheral side effects, including miosis, lacrimation, defecation and tachycardia (Benowitz et al., in: Nicotine Psychopharmacology, S. Wonnacott, M. A. H. Russell, & I. P. Stolerman, eds., Oxford University Press, Oxford, 1990, pp. 112-157; M. Davidson, et al, in Current Research in Alzheimer Therapy, E. Giacobini and R. Becker, eds.; Taylor & Francis: New York, 1988; pp 333-336).
In addition to treating decline in cognitive ability by improving cholinergic function and cerebral blood flow, it is also desirable to symptomatically treat the mental disorders accompanying the earlier stages of Alzheimer's Disease. Anxiolytics have been used to treat the severe agitation that most Alzheimer's patients experience with the initial loss of memory (INPHARMA, Mar. 16, 1991, pg 20). In fact, the use of anxiolytics has become an important aspect of treatment strategies for Alzheimer's Disease (Schmidt et al., Drug Dev. Res., 1988, 14:251). Nicotine is known to have anxiolytic properties (Pomerleau et al., Addictive Behaviors, 1984, 9:265) and, therefore, nicotine or selective nicotine agonists may be useful in the treatment of the anxiety associated with dementias, such as Alzheimer's Disease.
Others situations where beneficial therapeutic outcome may be achieved or improved through administration of nicotine or a nicotine agonist, because of the anxiolytic properties of these agents, include attentional deficit disorder and drug withdrawal.
Attention-deficit disorder (ADD), with or without hyperactivity, is a behavioral disorder characterized by distractibility and impulsiveness. Children with this disorder are handicapped by their inability to concentrate and control their impulsivity, especially in settings requiring sustained attention, for example, in school. While a cure for this disorder has not been found, stimulants, such as pemoline, have been used successfully in management of the behavorial manifestations of ADD. Nicotine, because of its ability to improve concentration and task performance (F. T. Etscorn, U.S. Pat. No. 4,597,961, issued Jul. 1, 1986; D. M. Warburton and K. Wesnes in Smoking Behavior, R. E. Thornton, ed., Churchill-Livingston, Edinburgh, 1978, pp. 19-43) is potentially useful in treating ADD.
Tobacco use, especially cigarette smoking, has long been recognized as a major factor leading to disease and death. Approximately 4,000 by-products of combustion, many of which are known carcinogens, have been found in cigarette smoke. Of the three most-studied constituents of cigarette smoke, two, tars and carbon monoxide, have been found to cause or exacerbate numerous life-threatening disorders. Tars are most often implicated in the induction of lung, larynx, oral cavity, esophageal and other cancers, and are also thought to be responsible for respiratory diseases, including pulmonary emphysema, chronic bronchitis and smokers respiratory syndrome. Carbon monoxide, on the other hand, combines with hemoglobin in the blood thereby decreasing the ability of the blood to carry oxygen and has been implicated as a causative agent in the development of coronary artery disease and arteriosclerosis. The third highly studied, and the most pharmacologically active substance, in tobacco products is nicotine, which is the reinforcing agent responsible for maintaining tobacco dependency (J. H. Jaffe in Nicotine Pharmacology: Molecular, Cellular and Behavioral Aspects, S. Wonnacott, M. A. H. Russell and I. P. Stolerman, eds., Oxford Science Publications, Oxford, 1990, pp. 1-37).
The nicotine withdrawal syndrome associated with smoking cessation is characterized by craving for nicotine, irritability, frustration or anger, anxiety, difficulty concentrating, restlessness, decreased heart rate and increased appetite or weight gain. Nicotine has, not surprisingly, been found to ease the withdrawal experienced by those attempting to break tobacco dependencies. As early as 1942, Johnston reported (L. Johnston, Lancet, 1942, 2:742) that injections of nicotine relieved the withdrawal symptoms experienced by cigarette smokers when they stopped smoking. More recently, in double-blind studies, nicotine was far superior to placebo in suppressing or preventing the appearance of many of the signs and symptoms of withdrawal (J. R. Hughes et al., Psychopharmacology, 1984, 83:82-7; N. G. Schneider et al., Addictive Behavior1984, 9:149-56; R. J. West et al., Journal of Addiction1984, 79:215-9; K. O. Fagerstrom in: Nicotine Replacement: a Critical Evaluation, O. F. Pomperleau and C. S. Pomperleau, eds., Alan R. Liss, Inc., New York, 1988, pp. 109-28; J. E. Henningfield and D. R. Jasinski, ibid, pp. 35-61). Irritability and impatience were reduced in at least five independent controlled studies, while anxiety and difficulty concentrating were reduced in at least two studies. Other symptoms for which nicotine was significantly more effective than placebo in at least one study include depression, hunger, somatic complaints, and sociability.
One approach to alleviating the symptoms of tobacco withdrawal has been to develop more efficient methods of delivering nicotine, itself, for example, in transdermal patches (F. T. Etscorn, U.S. Pat. No. 4,597,961, issued Jul. 1, 1986). The major problem with this approach is the non-selective effects of nicotine and in particular, the stimulant effects of increasing cardiac workload and oxygen demand that nicotine has on the heart. A selective nicotine agonist would be expected to be equally efficacious in relieving withdrawal symptoms with fewer cardiovascular liabilities.
Withdrawal from addictive substances in general, regardless of which particular agent is withdrawn, is a traumatic experience characterized by anxiety and frustration. These emotional disturbances contribute to failure in therapy and, consequently, to a return to substance dependence. Although ameliorating these symptoms does not eliminate the craving for the withdrawn drug, improving the individual's ability to cope and to concentrate should vastly improve the chances of successfully completing treatment. Nicotine has been found to be effective in reducing anger, irritability, frustration and feelings of tension, while increasing ability to focus upon the completion of tasks, without causing general response depression, drowsiness or sedation (R. R. Hutchinson et al., U.S. Pat. No. 3,879,794, issued Mar. 11, 1975).
It has now been discovered that compounds according to this invention are selective and potent nicotinic agonists useful in treating these problems.
No syntheses of fluorine-containing derivatives of nicotine have been reported. Acheson et al. have reported the preparation of 3'-bromonicotine (J. Chem. Soc. Perkin Trans., 1980, 1:579-85). Murphy reported that the 5'-cyanonicotine is a metabolite of nicotine (J. Biol. Chem., 1973, 248:2796-800), and Osdene et al. report that the compound has insecticidal activity (U.S. Pat. No. 4,093,620), but their disclosures cannot reasonably be said to suggest or anticipate the compounds of the present invention.
The syntheses of certain other substituted nicotine derivatives have been reported. For example, Shibagaki et al. (Japanese published application 62081381) describe various 5'-alkyl-substituted nicotine compounds which were synthesized for the purposes of "tobacco-related medical research". Edwards (U.S. Pat. Nos. 4,332,945 and 4,452,984) reports the synthesis of various 4'-substituted nicotine compounds with insecticidal activity. Still other nicotine compounds have been synthesized for reference purposes or in novel synthetic organic efforts (cf., Rueppel et al., J Amer. Chem Soc., 1971, 93:7021-8; Cushman et al., J. Org. Chem., 1972, 37:1268-71). None of the cited references, however, can be reasonably said to suggest or anticipate the compounds of the present invention, nor the use of these compounds as nicotinic agonists.

Nicotine derivatives that enhance cognitive function


An object of the invention is to minimize the number of in-process items. To this end, in an inter-process buffer controlling apparatus according to the invention, the size of a buffer to be used for storage of work subjects of predetermined work is increased if a difference or a ratio between a variance of first intervals at which the work subjects are delivered to the buffer and a variance of duration that is taken for the preceding process exceeds a prescribed first threshold value, and the size of the buffer is decreased if a difference or a ratio between an average of second intervals at which work subjects generated by the work are delivered to the following buffer and an average of the first intervals exceeds a prescribed second threshold value.

1. Field of the Invention
The present invention relates to an inter-process buffer controlling apparatus and method in which the size of an inter-process buffer for storing work subjects of a process is varied in a system in which a work is done through a plurality of processes, as well as to a program and a storage medium for realizing such an apparatus and a method.
2. Description of the Related Art
The Kanban System is known as a typical conventional system for reducing the number of in-process items. In this system, the number of in-process items is minimized because each process is executed in accordance with requirements that are given by the following process.
In this system, desired production is attained and the capacity utilization ratios of respective processes are kept high if tact balance among the processes is kept and the number of items being processed is relatively stable. However, in large-item-small-scale, custom-manufacturing production lines, the capacity utilization ratio and the production per unit time of a process concerned may lower to a large extent because not only a variation in actual tact time but also other various variations such as variations in amount and time due to the demand of customers and a variation relating to collection of parts occur depending on a product mix at each time. The term "actual tact time" means actual work time that is taken for each product in the process concerned rather than man-hours that is in proportion to the number of operators. The term "product mix" means a combination of products including their proportion and flowing order.
The TOC (theory of constrain) and the DBR (drum buffer rope) methods are known as methods for solving the above problems.
In these methods, inputting items to a production line in accordance with the capacity of a process (bottleneck process) having a lowest manufacturing capacity in the process prevents manufacture of unnecessary in-process items. And production is maintained by providing, at proper positions, a buffer having a certain capacity which prevents further reduction in the capacity of the bottleneck process due to suspension or a slowdown of operation that is caused from variations.
Incidentally, in the above conventional methods, a bottleneck process itself is not fixed and in many cases production is not maintained satisfactorily in the case where the product mix or the demand of customers varies to a large extent.
Further, in recent years, for many of products as subjects of large-item-small-scale production, shortening of a manufacturing period has come to be required strictly and the estimation of demand has become more difficult.
Therefore, not only a measure to minimize loss of variations in demand but also a measure to accommodate needs of customers should be provided urgently. A technique for further reducing the number of in-process items and actual process time with reliability without hindering reduction in the manufacturing cost is desired strongly. The term "actual process time" means time that is taken actually from a start to an end of each process and may include a time during which no work is done actually.

Apparatus and method for controlling inter-process buffer, and program and storage medium realizing the same


A fuel cell system acquires an operation state of a fuel cell and estimates an IV characteristic that indicates a relationship between a current and a voltage in the fuel cell. At least one of a resistance overvoltage, an activation overvoltage, a current-voltage hysteresis and a concentration overvoltage of the fuel cell is determined from the operation state of the fuel cell, and the IV characteristic is estimated based on the determined result.

A polymer electrolyte fuel cell, for example, is known as one type of fuel cell which generates electrical power utilizing an electrochemical reaction between hydrogen and oxygen. The polymer electrolyte fuel cell includes a stack which is constituted of a plurality of stacked cells. The cells constituting the stack each include an anode (fuel electrode) and a cathode (air electrode), and a solid polymer electrolyte membrane having a sulfonic acid group as an ion exchange group is interposed between each anode and cathode.
A fuel gas (hydrogen-enriched reformed hydrogen obtained by reforming hydrogen gas or hydrocarbon) is supplied to the anode, while an oxidant gas containing oxygen (for example, air) is supplied to the cathode as an oxidant. Upon the supply of the fuel gas to the anode, hydrogen contained in the fuel gas reacts with a catalyst in a catalyst layer which constitutes the anode, thereby producing hydrogen ions. The hydrogen ions produced thereby pass through the solid polymer electrolyte membrane and electrically react with oxygen in the cathode. Electrical power is thus generated through the electrochemical reaction.
As an example of such a fuel cell system, the invention disclosed in patent document 1 described below is suggested. The fuel cell system disclosed in patent document 1 described below suppresses a variation in the cell voltage of the fuel cell body while eliminating the waste of source gas and raw material supply power. Specifically, when a variation occurs in the voltage of a power-generating cell that constitutes the fuel cell body, a determination is made as to whether or not the cause is due to a source gas distribution inside the fuel cell body or a cell degradation, and a source gas stoichiometry ratio is set in accordance with the determined result.
As an example of such a fuel cell system, the invention disclosed in patent document 2 described below is suggested. The fuel cell system disclosed in patent document 2 described below does not prompt a user to inspect or exchange when there is a recoverable decrease in the current-voltage characteristic of a fuel cell, but is capable of prompting the user to inspect or exchange when the non-recoverable amount of decrease in the current-voltage characteristic of the fuel cell reaches a predetermined value. This fuel cell system estimates the current-voltage characteristic of the fuel cell body to judge the degradation of the fuel cell body. Specifically, the amount of decrease in the current-voltage characteristic from the pre-stored initial value V1 of the current-voltage characteristic to the present voltage value V3 is referred to as a first decreased amount, and the recoverable amount of decrease in the current-voltage characteristic when the operation is stopped is referred to as a second decreased amount. A third decreased amount obtained by subtracting the second decreased amount from the first decreased amount is a non-recoverable amount of decrease, and when the third decreased amount reaches the predetermined value, the user is prompted to inspect or exchange the fuel cell body.
As an example of such a fuel cell system, the invention disclosed in patent document 3 described below is suggested. The fuel cell system disclosed in patent document 3 described below stably extracts output without causing a hunting of an output limitation. Specifically, when an output voltage of the fuel cell falls below a voltage lower limit threshold value at which the fuel cell is capable of stably generating power, the current to be extracted from the fuel cell is limited, and when the output voltage rises and reaches the voltage lower limit threshold or higher, the limitation for the current to be extracted from the fuel cell is released, and further, the upper limit for the amount of increase in the current when the limitation for the current is released is computed.


An exemplary backlight module includes a frame (16) and a light guide plate (14) positioned in the frame. The frame defines a notch (164), which notch is bounded by a wall of the frame. The light guide plate includes a side surface (141), and an ear (144) extending from the side surface. The ear is received in the notch. A first protrusion (165) protrudes from either the wall of the notch or the ear and contacts the corresponding ear or wall of the notch.

Liquid crystal displays are commonly used as display devices for compact electronic apparatuses, because they not only provide good quality images with little power but are also very thin. The liquid crystal molecules in a liquid crystal display device do not emit any light themselves. The liquid crystal molecules have to be lit by a light source so as to clearly and sharply display text and images. Thus, a backlight module is generally needed for a liquid crystal display.
In a typical such liquid crystal display, the backlight module includes a plastic frame and a light guide plate positioned in the plastic frame. The light guide plate includes a plurality of ears integrally extending from a side surface thereof. The ears are respectively received in a plurality of notches of the plastic frame. Contact portions of the ears of the light guide plate and of walls that bound the notches of the plastic frame are generally planar surfaces. The contact portions of the ears and the notch walls are liable to rub against each other when the liquid crystal display is subjected to vibration or shock during operation or transportation. When this friction occurs, the liquid crystal display is liable to be noisy.
What is needed, therefore, is a backlight module that can overcome the above-described deficiencies. What is also need is a liquid crystal display employing such a backlight module.

Backlight module with noise damping protrusion and liquid crystal display with same


A single set of input devices (keyboard, mouse, etc.) is employed with a plurality of data processing systems each having a separate display. The logical display areas for the displays are arranged in a contiguous array to have common boundaries, with an edge (e.g., a right boundary or a lower boundary) of one logical display area coinciding with an edge of another logical display area (e.g., a left boundary or an upper boundary). When a cursor controlled by a pointing device is moved past a logical display area boundary which the current active data processing system shares in common with another data processing system, the active data processing system to which input device signals are transmitted is automatically switched to the other data processing system. No manual switching or hot-key sequence by the user is required, and the active data processing system may be automatically switch among any of a number of data processing systems simply by moving the cursor across logical display area boundaries between the data processing systems.

1. Technical Field
The present invention generally relates to improved concurrent use of multiple data processing systems and in particular to improved concurrent use of a single set of input devices (keyboard, mouse, etc.) enabling a user to interact with multiple data processing systems. Still more particularly, the present invention relates to an automatic keyboard/mouse switch enabling a single set of input devices to be employed by a user in interacting with multiple data processing systems without manual switching.
2. Description of the Related Art
Many data processing system users require the simultaneous use of multiple data processing systems, each system having a separate display and operating either separately from the remaining data processing systems or collaboratively as part of distributed system. For example, financial traders often need to be able to view and control several different systems at the same time in order to both receive required information from multiple sources and to concurrently make trades. Multiple systems are also frequently required for other reasons, such as where each workstation performs a dedicated function, redundancy is desired, etc.
Of course, user work space limitations or other practical considerations often preclude or inhibit the use of separate sets of input devices (such as a keyboard and mouse or other pointing device) for each of several data processing systems being concurrently employed by the user. Instead, a single set of input devices shared and switched between the multiple data processing systems is preferable. The current means for sharing input devices between multiple data processing systems generally requires the user to manually switch between the different data processing systems, either by operating a physical switch or entering a predefined keystroke sequence. Using a manual switch, the user can select the "active" data processing system (i.e., the data processing system to which user input through the keyboard or mouse is transmitted) by turning the switch to the appropriate position. Similarly, entry of a specific keystroke sequence allows the user to change the active system by signaling to the multiple systems that the change in active systems is desired.
All of the current solutions, however, require that the user interrupt the current task in order to manually perform the switch between multiple data processing systems. It would be desirable to provide a system, method, and computer program product which would allow the user to dynamically switch the active data processing system while continuing to work, and in the most unobtrusive manner possible.

International Business Machines Corporation


Aqueous binder compositions for fiber mats include a urea-formaldehyde resin and an aqueous emulsion of a copolymer prepared by polymerization of a monomer mixture including styrene, an alkyl(meth)acrylate, acrylonitrile, and an unsubstituted or substituted acrylamide. Even when used in relatively low concentration, the copolymer provides improved physical properties to the fiber mat. The fiber mats can be used in composite flooring, asphalt roofing shingles, siding, and dry wall.

Glass fiber mats and fiber mats made from other synthetic fibers are finding increasing application in the building materials industry, as, for example, in composite flooring, asphalt roofing shingles, siding, and dry wall. The glass fiber mats often replace mats traditionally made using wood, cellulose or asbestos fibers.
Fiber mats, and especially glass fiber mats, usually are made commercially by a wet-laid process, which is carried out on what can be viewed as modified paper making machinery. Descriptions of the wet-laid process may be found, for example, in U.S. Pat. No. 2,906,660 to Hungerford et al., U.S. Pat. No. 3,012,929 to Jackson, U.S. Pat. No. 3,050,427 to Slayter et al., U.S. Pat. No. 3,103,461 to Smith et al., U.S. 3,228,825 to Waggoner, U.S. Pat. No. 3,760,458 to Pitt, U.S. Pat. No. 3,766,003 to Schuller et al., U.S. Pat. No. 3,838,995 to Smith, and U.S. Pat. No. 3,905,067 to Keib et al. In general, the wet-laid process for making glass fiber mats comprises first forming an aqueous slurry of short-length glass fibers (referred to in the art as "white water") under agitation in a mixing tank, then feeding the slurry onto a moving screen on which the fibers enmesh themselves into a freshly prepared wet glass fiber mat, while excess water is separated therefrom.
Unlike natural fibers such as cellulose or asbestos, glass fibers do not disperse well in water. To overcome this problem, it has been the industry practice to provide suspending aids for the glass fibers. Such suspending aids or dispersants usually are materials that increase the viscosity of the aqueous medium. Suitable dispersants conventionally employed in the art include polyacrylamides, hydroxyethyl cellulose, ethoxylated amines and amine oxides. Other additives such as surfactants, lubricants, and defoamers also have conventionally been added to the white water. Such agents, for example, further aid the wettability and dispersion of the glass fibers. Experience has shown that such additives also often influence the strength of the wet glass fiber mat.
The fiber slurry deposited on the moving screen or cylinder is processed into a sheet-like fiber mat by the removal of water, usually by a vacuum device, and polymeric binder is then applied to the mat. In the manufacture of glass fiber mats, a high degree of flexibility and tear strength is desired in the finished mat in addition to primary dry tensile and wet tensile properties. A binder composition is therefore used to hold the glass fiber mat together. The binder composition is impregnated directly into the fibrous mat and set or cured immediately thereafter to provide the desired mat integrity. The binder composition can be applied to the mat by soaking the mat in an excess of binder solution or suspension, or by impregnating the mat surface by means of a binder applicator, for example, by roller or spray. The primary binder applicator for glass mat machines has been the falling film curtain coater. Suction devices often are also utilized for further removal of water and excess binder and to ensure a thorough application of binder through the glass fiber mat. A widely used binder is based on a urea-formaldehyde (UF) resin commonly fortified with an emulsion polymer. One advantage of urea-formaldehyde resins is that they are relatively inexpensive. In addition to mat strength properties which the binder composition imparts to the ultimately cured mat, the binder also functions to improve the strength of the uncured, wet-laid mat as it is transported from its initial formation into and through the curing oven. Such incipient pre-cured strength is needed to avoid process delays and shutdowns caused by breaks in the endless mat.
The incorporated binder is thermally cured, typically in an oven at elevated temperatures. Generally, a temperature in the range of about 200 to about 250° C. is used during curing. Normally, this heat treatment alone will effect curing of the binder. Catalytic curing, such as is accomplished with addition of an acid catalyst (for example, ammonium chloride or p-toluenesulfonic acid), generally is a less desirable, though an optional, alternative.
Because glass fiber mats made with a binder consisting essentially of a UF resin often are brittle, or because the strength properties of the mats may deteriorate appreciably subsequent to their preparation, especially when the mats are subjected to wet conditions. UF resin binders have commonly been modified by formulating the UF resin with cross-linkers and various catalyst systems or by fortifying the UF resin with a large amount of latex (emulsion) polymer, such as a poly(vinyl acetate), a poly(styrene-butadiene), a poly(styrene-maleic anhydride), a poly(styrene-maleic anhydride-acrylate), or a poly(styrene-acrylate). The use of poly(styrene-butadiene) and related copolymers in urea-formaldehyde resin compositions as a binder for glass fiber mats is disclosed, for example, in U.S. Pat. No. 4,258,098 to Bondoc et al., U.S. Pat. No. 4,560,612 to Yau, and U.S. Pat. No. 4,917,764 to Lalwani et al. The use of poly(styrene-maleic anhydride) copolymers and their hydrolyzed derivatives in urea-formaldehyde resin compositions as a binder for glass fiber mats is disclosed, for example, in U.S. Pat. No. 5,914,365 to Chang et al. The use of (1) poly(styrene-acrylic acid) or poly(styrene-acrylate), (2) poly(styrene-maleic anhydride-acrylic acid), or (3) a physical mixture of (1) and (2) in urea-formaldehyde resin compositions as a binder for glass fiber mats is disclosed in U.S. Pat. No. 6,642,299 of Wertz et al.
The addition of these polymers as a minor component of a urea-formaldehyde resin can improve both the wet and dry tensile properties of the glass mat. However, further improvements in properties are desired. Specifically, some product applications require mats having greater dry tensile strength, greater hot-wet tensile strength, greater elongation at break, greater tear strength, or a combination of two or more of these improved properties. There is also a desire to increase the productivity of methods of manufacturing the glass mats, which would require faster curing times and/or greater hot-wet tensile strength.

Binder compositions for fiber mats, and fiber mats and articles comprising them


A method and system of removing or decreasing waste liquor manganese concentration to less than about 1 mg/L total manganese without the precipitation of significant amounts of magnesium. The method and system include steps for treating the waste liquor using three separate circuits in which in the first circuit, manganese is reduced, for example, from about 2 g/L to <500 mg/L using pH adjustment with a suitable neutralizing agent; and in the second circuit, the final target manganese level is achieved by oxidative precipitation using a suitable oxidizing agent. Part of the precipitated manganese product, e.g., MnO2, is recycled to the oxidative precipitation circuit as seed and the balance proceeds to a third circuit wherein the precipitated manganese product is re-dissolved, and then recycled to the first neutralization circuit. In the first neutralization circuit and the second oxidative precipitation circuit, the process conditions are selected to minimize the precipitation of magnesium, e.g., Mg(OH)2.

The present invention relates to the hydrometallurgical processing of nickel laterite ores and, in particular, to an improved method and system for selectively removing manganese (Mn) from nickel laterite waste liquors, allowing the effluent stream to be safely discharged to the environment.
Most of the world's remaining nickel (Ni) resources are contained in nickel laterites. These oxidic ores attracted considerable attention from nickel producers in recent years, especially for the application of leaching technology. This was partly due to advancements in pressure autoclave technology and materials of construction, large available ore bodies, and amenability of deposits to surface mining methods. The low-Mg, high-Fe limonitic fraction of the laterite profile is best suited for hydrometallurgical processing. The laterite projects developed over the past 15 years used exclusively high-pressure acid leaching (HPAL) to process the limonitic ores.
An important consideration in the processing of the limonitic ores is the disposal of waste products. Typically, large waste streams are generated in the process. A plant that produces 60,000 tonnes/year nickel could generate 2000-3000 m3/h of liquid waste. These large volumes arise from the need to process large tonnage of ores since the grade of the limonitic ore (1-1.6% Ni) is relatively low and the ore is not amenable to standard concentration methods owing to the presence of the paymetals (nickel and cobalt) in solid solution within the host minerals.
The HPAL process dissolves most of the ore solids releasing both the paymetals and the associated impurities. The main impurities are iron (Fe), manganese (Mn), aluminum (Al), silicon (Si), chromium (Cr), and magnesium (Mg). Some of the impurities, notably Fe, enter the solution and then undergo hydrolytic precipitation reactions within the autoclave and report to the leach residue. Despite this initial rejection of impurities, the autoclave discharge still contains significant amounts of impurities, which are separated in a series of unit operations.
Manganese and magnesium are two elements that dissolve in the autoclave and persist in solution. The waste liquor from the HPAL process typically contains about 1-3 g/L Mn and 2-15 g/L Mg, depending on the feed composition. Manganese is an environmentally regulated element requiring removal to less than 1 mg/L before the treated liquid stream can be safely discharged to the environment.
The standard practice used in the recently proposed laterite projects is to remove the Mn in the effluent stream as Mn(OH)2 by pH adjustment using lime neutralization. A pH in the range 8.5-9.5 is required to achieve less than 1 mg/L Mn. The main drawbacks of this approach are high reagent consumption due to the co-precipitation of nearly all the Mg (>98% Mg precipitation) as Mg(OH)2 and poor settling properties of the precipitated mixed Mn/Mg hydroxide product. The hydroxide product is gelatinous and difficult to handle and pump. Also, the additional Mg precipitation increases the tailings tonnage, and since the mixed hydroxide product is low-density, the consolidated settled density of the tailings in the storage pond is lower, significantly raising the required annual storage volume.
An alternative approach is to use oxidative methods to precipitate Mn. The oxide product settles and filters well. However, it has a high oxidizing capacity and there exists the possibility of undesirable side reactions during the disposal and storage of the Mn oxide waste stream; it is known, for example, that the manganese oxide product can oxidize chromium that is universally present in the effluent residues, releasing toxic hexavalent chromium (Cr6+)) into the residue pond water. Also, the removal of all the Mn by oxidative methods alone will be uneconomical because of the high level of Mn in the effluent stream and the high cost of oxidants.
Manganese can be readily oxidized to Mn (IV) and precipitated using many oxidants, such a mixture of SO2 and O2 or air. However, the SO2/O2 chemistry is not well understood and each aqueous system will have a different response to the application of this oxidant, depending on the prevailing chemistry of the system.
Berglund et al. reported that the addition of Mn3+ significantly increased the oxidation rate of Mn2+. See [1] J. Berglund, S. Fronaeus, and L. I. Elding, "Kinetics and Mechanism for Manganese-Catalyzed Oxidation of Sulfur(IV) by Oxygen in Aqueous Solution" Inorg. Chem. 32 (1993): p. 4527-4538; [2] J. Berglund and L. I. Elding, "Reaction of Peroxomonosulfate Radical with Manganese(II) in Acidic Aqueous Solution" J. Chem. Soc., Faraday Trans, 90 (21), (1994): p. 3309-3313. Zhang et al. showed that the addition of 2.7 mM hydroquinone, which is a free radical scavenger and effective reductant of Mn3+ and peroxy species, could completely stop the oxidation reaction. See [3] W. Zhang, P. Singh, D. Muir, "Oxidative Precipitation of Manganese with SO2/O2 and Separation from Cobalt and Nickel", Hydrometallurgy 63, 2002, pp. 127-135; [4] W. Zhang, "SO2/O2 as an Oxidant in Hydrometallurgy", Ph.D. Thesis, Murdoch University, Western Australia, February 2000.
Several patents have been filed for the use of SO2/air in effluent treatment: for mine drainage and waste pickling liquor (U.S. Pat. No. 3,738,932), for removing heavy metals from wastewater (Canadian Pat. No. 1,183,974), for removing arsenic from solutions containing sulfur dioxide (Canadian Pat. No. 2,255,874), and for removing cyanide, arsenic, and antimony from effluent streams (Canadian Pat. No. 1,241,774). These effluent streams have entirely different properties and requirements from those of laterite leaching waste liquors.
Various methods for the removal of Mn using the SO2/O2 or air method are known. Examples of such methods are taught in WO 00/56943 and WO 03/054238. However, both references are concerned with the purification of cobalt (Co) solutions and neither refers to the treatment of laterite waste liquors or, more importantly, the need to reduce total Mn to extremely low levels, less than 1 mg/L.

Method for removing manganese from nickel laterite waste liquors


In evaluating commonality of documents, each sentence is represented by a binary vector whose components indicate the presence or absence of corresponding terms, whereupon the concept of a common vector among documents is introduced. One sentence vector is derived from each of the documents to form a group of sentence groups, and only components which assume “1” (one) in all the vectors are “1”, the other components being “0” (zero). The commonality of a document set is evaluated by employing the sum or squared sum of the numbers of components whose values are not zero in the individual common vectors, for all the common vectors.

1. Field of the Invention
The present invention relates to natural language processing which includes document summarization. More particularly, the present invention makes possible to quantitatively evaluate the commonality of topics among a large number of documents, thereby enhancing the processing performance.
2. Description of the Related Art
When a document set consisting of a plurality of documents is provided, the quantitative evaluation of a topical commonality for the document set necessitates the following techniques:
(A) The degrees to which the topics of the individual documents are common are indicated by numerical values so that whether or not a common topic exists in the document set can be judged.
(B) The individual documents or individual sentences are scored in accordance with the degrees of closeness to a common topic so that the documents or sentences containing topics close to the common topic can be selected from within the document set, to thereby discern the common topics among all the documents.
(C) Even when a topic is not common to all the documents, any group of documents whose topics are common is extracted.
Regarding item (A) of these techniques, in the case of two documents, the score of the commonality of topics can be considered to be the similarity between the two documents, and various measures for the similarity have heretofore been proposed. The most typical measure is the cosine similarity, wherein each document is represented by a vector whose components are the frequencies of individual terms occurring in the document, whereupon the similarity between the two documents is defined by a cosine formed by the vectors of the respective documents.
Items (B) and (C) are techniques which pertain to the extraction of common topics from within a document set. Such processing is important in multi-document summarization, TDT (Topic Detection and Tracking), etc. Heretofore, the extraction of the common topics has been implemented by clustering documents and thereafter selecting sentences or document titles that can typify the respective clusters. Recently, there has also been proposed a method in which common topics are extracted by forming clusters in sentence or passage units and selecting the important passages of the respective clusters. Clustering has heretofore been a technique that is indispensable to the extraction of the common topics. This clustering is broadly classified into a hierarchical technique and a non-hierarchical technique.
The hierarchical technique is subclassified into a bottom-up approach and a top-down approach. In the bottom-up approach, individual documents are set as the seeds of clusters as an initial state, followed by merging the closest clusters, and the process is iterated until the number of clusters becomes equal to 1 (one). Thus, a document set comes to be represented by a tree structure. The top-down approach iterates a process that starts from a state where all documents belong to a single cluster, and in which, when the lowest similarity in all document pairs within the single cluster is less than a threshold, the cluster is divided. In the non-hierarchical technique, a predesignated number of clusters is created so as to satisfy any criterion. A well-known method includes step 1 at which documents in the designated number of clusters are selected at random and are set as the centers of the respective clusters, step 2 at which the degrees of closeness to the respective cluster centers are evaluated for every document, whereupon the respective documents are caused to belong to the closest clusters, step 3 at which the center of each of the resulting clusters is found on the basis of the average of the vectors of the documents belonging to the corresponding cluster, and step 4 at which the processing of the step 2 is executed, and the routine is ended if the clusters to which the respective documents belong have not changed, or the routine is returned to the step 3 if they have changed.
Regarding the technique (A), as stated above, any measure corresponding to the similarity in the case of the two documents has not been known for a case of three or more documents. Therefore, when a group of three documents stating similar topics coexists with a group of four such documents, it has been impossible to answer a question; "Which of the groups have the closest content matches?" The present invention provides a measure that can answer even such a question.
In the extraction of the common topics in the techniques (B) and (C), the bottom-up hierarchical clustering process cannot guarantee that the clusters at each level is meaningful. In aiming at meaningful grouping, only each pair of clusters whose similarities exceed a threshold can be merged, but how to determine the threshold is problematic. Also in the case of the top-down hierarchical clustering process, how to determine the threshold for whether or not the cluster is divided is problematic. Moreover, the problem of a processing complexity cannot be overlooked in the hierarchical technique. In the non-hierarchical technique, it is required to previously know how many clusters a given document set includes. However, the previous knowledge is information that is generally unobtainable, and it is difficult to accurately designate the number of clusters. In this manner, the clustering technique itself has not been completely established. Accordingly, even when the extraction of the common topics has been implemented using the prior-art clustering technique, it is not guaranteed to be optimal. For such reasons, the present invention provides a common-topic extraction method that does not resort to the prior-art clustering technique.

Evaluating commonality of documents using segment vector, co-occurrence matrix, and common co-occurrence matrix

Hewlett-Packard Development Company, L.P.


Techniques and circuits for generating a pair of differential signals with balanced switching between logical states from a single ended input signal are provided. The differential signals may be generated by controlling the switching of substantially identical driver stages with a set of control signals generated based on the single ended input signal.

1. Field of the Invention
The present invention generally relates to electronic circuits and, more particularly, to a circuit and technique for generating a pair of differential signals from a single ended signal.
2. Description of the Related Art
To meet the computing industry's growing demands for high speed data transfer between components, many systems forego conventional parallel buses to high speed synchronous serial buses. In such systems, data is transferred between devices on a serial bus, synchronized to a clock signal. For example, in a gaming system, such a serial bus may be used to transfer data between a central processing unit (CPU) and a graphics processing unit (GPU). A receiving component will typically transfer the serially received data to some component for de-serialization, converting the serial data into for presentation on wider internal buses for efficient processing. For example, data transferred over a high speed serial 8-bit bus may be processed internally using a 64-bit bus.
In some cases, in order to route data internally (e.g., for serialization or de-serialization) single ended signals may be converted to differential signal. By utilizing lower voltage swings than single ended signals, differential signals can generally provide higher data throughput. This is possible because the differential threshold in a differential receiver is typically more easily controlled than the threshold of a single transistor. The lower voltage swings can also result in reduced power consumption and reduced switching noise and crosstalk, as the opposite currents carried on differential signal traces tend to cancel the electric and magnetic fields.
FIG. 1 illustrates an exemplary conventional differential signal driver circuit 100 for generating a pair of differential signals OUTX and OUTY from a single ended input signal XIN. As illustrated, switching signals X1 and XB may be generated from the input signal XIN via a pair of inverters 112 and 114, respectively. These switching signals may be used to control the switching of transistors 102 and 104. A bias voltage VBIAS applied to a transistor 106 may be used to control the total current flowing through the switching transistors 102 and 104. Load resistors 108 may be sized accordingly to the impedance of the transmission line.
Operation of the driver circuit 100 may be explained with reference to the timing diagrams 200 and 210 shown in FIG. 2. Waveforms for signals X1 and XB are shown as waveforms 202 and 204, respectively. Waveforms for the differential output signals OUTX and OUTY are shown as waveforms 214 and 212, respectively The illustrated example assumes that the input signal XIN begins in an initial low state. Consequently, X1 is in a high state and XB is in a low state, causing transistor 102 to be turned on and transistor 104 to be turned off. As a result, node X is pulled down, keeping differential signal OUTX in a low initial state, while node Y is pulled up, keeping differential signal OUTY in a high initial state.
XIN then transitions to a high state, causing X1 to begin transitioning to a low state, at a time t0. Once X1 falls below a switching threshold of transistor 102, at time t1, transistor 102 will turn off and node X will begin charging, causing OUTX to transition to a high state. Due to the delay associated with the inverter 114, XB will not begin transitioning to a high state until a time t2 after X1 has begun transitioning. As a result, XB will not reach a switching threshold of transistor 104, until a later time t3, finally causing transistor 104 to turn on and node Y to begin discharging, bringing OUTY to a low state, which is finally reached at t4.
The differential signal pair OUTX and OUTY is typically routed to a receiver at some other location on a circuit board that converts the differential signal pair back to a single ended signal. Unfortunately, the delay D between switching of differential signals OUTX and OUTY, caused by the inverter delay between switching signals X1 and XB, can result in duty cycle distortion. In other words, the single ended signal generated by the receiver may have an asymmetrical duty cycle, for example, assuming an input signal pattern alternating between high and low states, with one logic state of the signal waveform being greater than the other. In some cases, the single ended signal generated by the receiver may be synchronized with a clock signal having a symmetrical (50%) duty cycle for high and low states. In such cases, the asymmetry of the logic states may result in reduced timing margins.
Accordingly, what is needed is a technique for generating a pair of differential signals with balanced switching between logical states.

Balanced single ended to differential signal converter


An air sterilization device with low aerosol bounce includes an air conditioning pipe, a porous filter media, and a UV light generator. This porous filter media, it is secured on the fixing portion. This porous filter media has many irregularly distributed channels. The channel is coated with a coating layer having a thickness between 10 μm to 1000 μm sticking aerosols for avoiding bounce effect. The UV light generator can emit UV light to kill biological aerosols. It is suitable for long-term usage. So, the bounce effect of aerosols can be significantly reduced. The maintenance cost is low. The sterilization effect is excellent. Plus, the flow rate of the air conditioning system remains high.

1. Field of the Invention
The present invention relates to an air sterilization device with low aerosol bounce. Particularly, it relates to an air sterilization device that contains a porous filtration media with a coating layer and a UV (ultraviolet) light generator. So, the bounce effect of aerosols can be significantly reduced. The maintenance cost is low. The germicidal effective rate is excellent. Plus, the flow rate of the air conditioning system remains high.
2. Description of the Prior Art
The conventional air sterilization methods at least include: using a filter to capture the solid aerosols in the air, utilizing UV light to emit on bacteria in the air directly; coating with a photocatalysis layer to cooperate with a UV light source to activate the photo-catalytic reaction in order to kill the bacteria, etc.
The first conventional method is to use a filter to capture the solid aerosols in the air. Referring to FIGS. 1 and 2, the conventional air conditioning system has a pipeline 90 (or ventilation duct). A general filter 80 is installed in a proper position (such as near the fresh air entrance or near exit) of this pipeline 90. This general filter 80 has a thickness X. The general filter 80 consists of many filtration fibers 81. There are many small openings 82 among the filtration fibers 81 for allowing air to flow through. The porosity of a general filter 80 is large; therefore the flow resistance (or called pressure drop) is small. The flow resistance and price of the filtration fibers 81 are significantly lower than the ones of foam or the ones of a high efficiency particulate air filter (or briefly referred as HEPA filter). As shown in FIG. 3, the eighteenth curve L18 represents a general filter 80. The nineteenth curve L19 represents foam. The twentieth curve L20 represents the HEPA filter. Theoretically, dusts or particles in the airstream can be captured by the filter fibers 81 based on the single fiber theory. The single fiber theory includes gravitational settling, inertial impaction, interception, diffusion, and electrostatic attraction. Because the porosity of the general filter is too large and the packing density of the filter is too small, the filtration efficiency cannot be increased. As a result, the collecting efficiency of the general filter is low. It is also lower than the one of the foam or the HEPA. Referring to FIG. 4, concerning the penetration rate of aerosols, the eighteenth curve L18 represents a general filter 80. The nineteenth curve L19 represents foam. The twentieth curve L20 represents the HEPA filter. Therefore, in order to achieve the high filtration efficiency, low flow resistance is required, because the flow resistance will significantly influence the energy consumption. Moreover, a good filter must have an excellent collecting efficiency and low flow resistance. That is, it must have a satisfactory filter quality (briefly referred as qF). The filter quality can be defined by the following equations (1) and (2).
                              q          F                =                                            -              ln                                                                                P                                Δ                                                                          p                                              (        1        )            P=1−Eff  (2)
where                P: aerosol penetration;        Δp: flow resistance (or pressure drop);        Eff: collection efficiency.
The flow resistance is the overall loss for the air flow through this filter, and is proportional to the filter thickness, packing density, flow velocity and the total surface area of the filter fibers. Hence, if the collection efficiency increases, the flow resistance also increases. By reducing filter flow velocity and adding more filter material in the same filter volume, the filter collection efficiency will improve. However, it increases the total cost for filter material. It is possible to happen that some of the solid aerosols 83 (or particles) with greater inertial force impact on the filter fibers 81 and then bounce off, as illustrated in FIG. 5 (the effect of bounce off). It will make some aerosols 83 to occur the re-entrainment phenomenon. Therefore, many aerosols 83 continue to penetrate through the filter material. It significantly reduces the collecting efficiency of the filter. For most air condition system (including heating, ventilating and air conditioning, briefly called HVAC), the flow velocity in the pipeline is high as in the range of 50˜300 cm/s (or even higher) depending on the capacity and application scope of the air conditioning system. Thus, once the flow velocity increases, the flow resistance increases, too.
The second conventional method is to utilize UV light to emit on bacteria in the air directly. The best wavelength of UV light is 253.7 nm (in the range of Ultraviolet C, short wave; briefly called UV-C; 280 nm-100 nm). However, the flow velocity in the pipeline is roughly 50˜300 cm/s. The aerosols carried by the airstream are also moving at that velocity. Under such high flow velocity, the time of UV light exposure is too short to kill these biological aerosols.
The third conventional method is to coat with a photocatalysis layer to cooperate with a UV light source to activate the photo-catalytic reaction to kill the bacteria. The photocatalysis layer can decompose some biological aerosols (or bacteria) into CO2 and water. Titanium dioxide (TiO2) is a commonly used photocatalysis. While being exposed to UV light or the solar light, it generates free radicals (hydroxyl radicals: OH) and creates electron-hole pairs, so that it can oxidize an organic object. The energy level is 3.2 eV for the anatase form of the titanium dioxide in a photochemical reaction. When titanium dioxide is exposed by the light having the wavelength less than 385 nm, electron will be exerted to the conduction band and leave one electron-hole that reacts with neighboring H2O and OH−. Therefore, in order to achieve the sterilization effect, the photocatalysis layer must contact with the target (such as the biological aerosols). In this sterilization system, the biological aerosols must contact with those hydroxyl radicals to achieve the function of sterilization.
However, if the filter material is coated with a photocatalysis layer, it does not consider that such system might work due to the bounce effect. Especially, the bounce effect is obvious for those aerosols with larger size. Under this condition, the overall collection efficiency will decrease. If someone wants to coat with a coating layer (to reduce the effect of aerosol bounce off) on the photocatalysis layer, the photocatalytic reaction will not work well due to low contacting portion between biological aerosols and photocatalysis layer. Besides, the photocatalysis layer is quite expensive. If this system is installed in a pipeline of an air conditioning system, it will create many problems. Furthermore, usually UV-A (Ultraviolet A, long wave, or called UVA; 400 nm-315 nm) is applied to activate the photocatalytic reaction. However, the UV-A has a less efficiency to kill the biological aerosols directly. The major function of UV-A is to activate the photocatalytic reaction.
The problems of these conventional methods can be listed below.
[1] It is hard to capture the bioaerosols (a brief term for biological aerosols) with larger size due to the bounce effect. For those bioaerosols with large size, they have high moving velocity due to inertial force. Once they impact on a surface, they tend to bounce off. So, the overall collection efficiency is low. According a study (Aino, N, 1993), the average diameter of virus is about 0.02˜0.3 μm. The average diameter of fungal spore or bacteria is about 3˜100 μm. For example, small aerosols (such as virus) can be captured by diffusion or electrostatic attraction. Large aerosols (such as fungal spore, bacteria, dust, etc.) can be captured by inertial impaction, interception, and gravitational settling. About the inertial impaction, the objects might be bounce off, so that they still can penetrate through the filter. Particularly, the fungal spore and bacteria can bounce off and spread away via the central air conditioning system in a hospital. It is hard to image how terrible the consequence is.
[2] HEPA is expensive and has high flow resistance. When a HEPA filter is used, the collection efficiency can increase to 99.97% or higher. It seems to be an ideal solution to capture bioaerosols (including the bacteria, fungal spore, pathogens, etc.). It also can avoid the bounce effect. However, the maintenance cost of HEPA filter is too high. Filter in any air conditioning system needs to be replaced periodically. The price of the HEPA filter is approximately ten times higher than the one of a general filter. Besides, because the collection efficiency is high, the collected particles or aerosols will stay in the filter to block the air and then form a blocking portion (or called a dust cake). As a result, the flow resistance is increased without any limit. In order to avoid that, usually the replacement period will be shortened. For example, the maintenance period should be shortened from once a month to twice a month. That means the cost is double per month. In addition, when the flow resistance increases to a certain level, the fan of this air conditioning system will consume more electricity. For example, if someone uses the HEPA filter to replace the general filter, the maintenance at least increases 20 times (10×2). The cost is extremely high.
[3] The sterilization effect is poor. In a traditional air condition system, there is no any sterilization equipment. Although sterilization equipment is installed, it might be installed on at the entrance or the exit of the system. There is no sterilization equipment installed in the middle of the pipeline. For those bioaerosols captured by the filter, they will not die immediately. These bioaerosols are just be stuck at a place. In case of the environment is good for growing up (for example: having enough water (high relative humidity) and nutrition), these stuck bioaerosols still can remain survive, multiply and even reproduce. Hence, that filter becomes the home of bioaerosols. The reproduced bioaerosols also can be widely spread out to more rooms and corners via the pipeline of the air conditioning system. More people might be infected. If the filter is coated with a photocatalysis layer, it does not consider overcoming the bounce effect. Therefore, the collection efficiency for large aerosols is low. The photocatalysis layer is useless, if the filter is covered by another material to reduce the bounce effect, the photocatalysis layer becomes invalid. Besides, the UV-A is used to activate the photocatalyic reaction. The sterilization effect of UV-A is relative lower than UV-C. In addition, the photocatalysis layer must contact with the bioaerosols. If the non-biological aerosols are stuck on some portion of the photocatalysis layer, only the rest portion of the photocatalysis layer still can conduct the photocatalytic reaction. Thus, the overall sterilization effect becomes low. Generally, the non-biological aerosols are more than the biological aerosols in the air. So, the function of photocatalysis layer will be reduced by the non-biological aerosols.
In addition, in the pipeline, all the aerosols are carried by the airstream under the flow velocity about 50˜300 cm/s. If one system only utilizes the UV light as the germicidal irradiation, the flow retention time seems too short to let the UV light work well. Furthermore, the pipeline includes many branches and sub-branches. Usually there is no any filtration device or sterilization equipment to capture these aerosols. Besides, aeorosols are possible to enter the pipeline, branches or other sub-branches via some connecting gaps, broken holes, cracks, water leaking, and so on. The aerosols can spread out through the pipeline. For example, there are patients, doctors, and nurses in the hospital all the time. It is impossible to vacate the entire hospital to conduct a full-hospital sterilization. Thus, the aerosols stayed in the pipeline might spread out and make all the members (including critical patients, patients in respiratory therapy, hospital workers, etc.) in the hospital to be infected. It is a very serious problem.

Air sterilization device with low aerosol bounce

Institute of Occupational Safety and Health, Council of Labor Affairs, Executive Yuan


A light-emitting device including a light-emitting element and a substrate where the light-emitting element is arranged. A housing part housing the light-emitting element and having a shape that is tapered upward from the substrate and a metal frame surrounding the light-emitting element and including the side face of the housing part made into an almost mirror-polished surface are provided on the substrate.

The present invention relates to a light-emitting device and its manufacturing method and in particular to a light-emitting device that uses a face of a housing part for housing a light-emitting element as a reflector and its manufacturing method.
FIG. 1 is a cross-sectional view of a related art light-emitting device. θ1 shown in FIG. 1 represents the inclination angle of the side face 109A of a housing part 109 with respect to the bottom face 109B of the housing part 109 (hereinafter referred to as the "inclination angle θ1").
Referring to FIG. 1, the related art light-emitting device 100 includes a substrate 101, a light-emitting element 102, a phosphor-containing resin 103, and a sealing resin 104.
The substrate 101 includes a substrate main body 106 and a wiring pattern 107. The substrate main body 106 includes a housing part 109 and a plurality of through holes 111. The housing part 109 is intended to house the light-emitting element 102. The housing part 109 has a shape that is tapered upward from the bottom 109B of the housing part 109.
The side face 109A of the housing part 109 is an inclined surface forming an inclination angle θ1 with respect to the bottom face 109B of the housing part 109. The side face 109A of the housing part 109 is arranged to surround the light-emitting element 102. The side face 109A of the housing part 109 functions as a reflector to reflect light emitted from the light-emitting element 102. A material for the substrate main body 106 may be ceramic or a resin. Note that a resin has a problem that it is deteriorated by ultraviolet rays contained in the light emitted from the light-emitting element 102 and thus ceramic is preferable as a material for the substrate main body 106. In case ceramic is used as a material for the substrate main body 106, the housing part 109 is formed by countersinking (scraping) a ceramic substrate.
The wiring pattern 107 is arranged to fill the through holes 111 and reach the lower face 106A of the substrate main body 106 via the through holes 111. The light-emitting element 102 is flip-chip connected to the wiring pattern 107 via a bump 112.
The phosphor-containing resin 103 is arranged to cover the light-emitting element 102. The sealing resin 104 is arranged on the housing part 109 so as to seal the light-emitting element 102 covered with the phosphor-containing resin 103. (For example, refer to Patent Reference 1.)
[Patent Reference 1] JP-A-2005-311314
However, the related art light-emitting device 100 forms a housing part 109 by countersinking (scraping) a ceramic substrate, so that it is impossible to obtain a sufficient flatness of the side face 109A of the housing part 109 and it is thus difficult to efficiently reflect the light emitted by the light-emitting element 102 with the side face 109A of the housing part 109. This results in a problem that the lighting efficiency of the light-emitting device 100 is reduced.
The related art light-emitting device 100 has a housing part 109 formed on a substrate 101. For example, to change the inclination angle θ1 of the side face 109A of the housing part 109, the entire substrate 101 must be replaced with another substrate, which adds to the costs of the light-emitting device 100.

Light-emitting device and method for manufacturing the same


Door stop and impact absorber bracket for restraining mailbox doors from opening beyond a selected swing radius. The bracket can fit underneath the mailbox behind an existing lower hanging lip. The door stop bracket is positioned such that it limits the door from swinging beyond a desired point (for example approximately 90 degrees) when the door is opened. The bracket can have an elongated rectangular planar central portion, with bent ends, together forming a generally C-shape. The bracket can have cushion pad to protect both the door, hinges other components and even the body of the mail box from being damaged from excessive vibrations when the door reaches the maximum opening point. The pad can also reduce objectionable impact noise effects that are created when a mailbox door accelerates in a free fall to a stop.

Mailboxes have been around for many years, and come in many sizes and shapes. The most popular mailboxes have an elongated compartment such as a rectangular housing with a flat roof or curved roof, and an access door that swings open based on a hinge mechanism the attaches the door to the lower front edge of the mailbox. However, mailbox doors tend to open much further than is needed. A typical mailbox door swings freely up to approximately 180 to approximately 270 degrees or more from a vertical upright closed position. The loosely swinging door has resulted in many problems.
For example, a mailbox door that hangs down is more prone to be twisted and bent overtime rendering the door useless from closing the mailbox. A downwardly hanging door can also break off from the mailbox leaving the interior of the mailbox continuously open. A constantly open mailbox can allow for any mail type contents inside to become damaged by being exposed to weather elements, and/or allow for the mailbox contents to become dislodged and lost, and even stolen overtime.
Additionally, a downwardly hanging bent and/or twisted mailbox door or portions of a door that remain can also be a snag hazard to others such as a mailman.
Still furthermore, most mailboxes being metal are prone to additional problems. These mailbox doors typically swing open so that metal eventually impacts metal that can cause damage to either or both the door, the handle, hinges, floor, other components and even the mailbox itself overtime. Metal hitting metal has also been known to cause objectionable loud impact noises that are created when a mailbox door accelerates in a free fall to a dead impact stop.
The constant banging between components can stress mailbox door hinges, other rotating points, welds and other assembly components causing parts to warp and/or loosen and/or fall off and/or become damaged overtime reducing the life of the mailbox.
The inventor is not aware of apparatus, devices and methods that overcome all the problems listed above. Thus, the need exists for solutions to the above problems with the prior art.


Disclosed is an energy-saving and environment-friendly double-row air duct heater, including a bottom plate and a shell. A motor and fan blades are arranged on one end in the shell. The upper part of the shell is provided with a control device. A heating component is arranged on the other end in the shell. An air inlet is formed at the rear end of the shell, and an air outlet is formed at the front end of the shell. The heating component includes an air volume drainage device. Two groups of electric heating pipes are arranged on both sides of the air volume drainage device. Each group of electric heating pipes is composed of a plurality of vertically arranged electric heating pipes. An air guiding passage is formed between two adjacent electric heating pipes.

At present, the existing axial-flow electric heater mainly directly blows a heating body to produce forced convection for space heating. However, due to the limitation of blade structure, there is no wind in the middle of the blade. When the blade rotates, the middle of the blade is at negative pressure under the influence of centrifugal force, resulting in that there is no wind in the middle or the wind direction is opposite. The wind blowing through the surface of an electric heating pipe of the heater is not uniform, resulting in high temperature in some electric heating pipe positions and low temperature in some other positions, poor heating effect and low thermal efficiency.

Energy-saving and environment-friendly double-row air duct heater


An oxide semiconductor includes a first material including at least one selected from the group consisting of zinc (Zn) and tin (Sn), and a second material, where a value acquired by subtracting an electronegativity difference value between the second material and oxygen (O) from the electronegativity difference value between the first material and oxygen (O) is less than about 1.3.

(a) Field of the Invention
Exemplary embodiments of the invention relate to an oxide semiconductor, a thin film transistor including the oxide semiconductor, and a thin film transistor array panel including the thin film transistor.
(b) Description of the Related Art
Flat panel displays such as a liquid crystal display ("LCD"), an organic light emitting diode ("OLED") display, an electrophoretic display, a plasma display, for example, typically include multiple pairs of electric field generating electrodes and an electro-optical active layer interposed between the pairs of electric field generating electrodes. The LCD includes a liquid crystal layer as the electro-optical active layer, and the OLED includes an organic light emitting layer as the electro-optical active layer. In flat panel displays, one of a pair of electric field generating electrodes may be connected to a switching element to receive an electric signal, and the electro-optical active layer converts the electric signal into an optical signal to display an image.
The flat panel display may include a display panel having a thin film transistor, e.g., a thin film transistor array panel. The thin film transistor array panel may be patterned with multiple electrodes and semiconductors, and masks may be used in the patterning process.
In the thin film transistor array panel, the semiconductor is an important factor in determining the characteristics of the thin film transistor therein. In the semiconductor including amorphous silicon, the charge mobility therein is low such that there is a limit in manufacturing a high performance thin film transistor. In the semiconductor including polysilicon, the charge mobility therein may be high such that the high performance thin film transistor may be effectively manufactured, while the manufacturing cost may be high and uniformity is low such that there is a limit in manufacturing a large-sized thin film transistor array panel.
Accordingly, a thin film transistor using an oxide semiconductor having high charge mobility and a high ON/OFF ratio of current compared with amorphous silicon and having a low cost and high uniformity compared with polysilicon has been researched.
Research on using zinc oxide (ZnO), tin oxide (SnO2) and zinc-tin oxide (ZnSnO) as the oxide semiconductor has progressed. Furthermore, research on adding a new material to an original material has progressed to improve the characteristics of the oxide semiconductor; however, a conventional method used to determine the added material, which is performed without a theoretical base in the periodic table, may be inefficient since a sample of the thin film transistor is manufactured, and the characteristics thereof are verified for the method.

Oxide semiconductor, thin film transistor including the same, and thin film transistor array panel including the same


A split-counter architecture is implemented within an image sensor system. A first counter within an image sensor region counts image data from pixel regions within the image sensor region, and outputs the most significant bits of the image data to a second counter external to the image sensor region, reducing the bandwidth required between the image sensor region and the second counter, and reducing the size of the counters within the image sensor region.

Digital image sensors, such as CMOS or CCD sensors, include a plurality of photosensors each configured to convert photons incident upon the photosensors ("captured light") into electric charge. The electric charge can then be converted into image data representing the light captured by each photosensor. The image data includes a digital representation of the captured light, and may be manipulated or processed to produce a digital image capable of display on a viewing device. Image sensors are implemented in integrated circuits ("ICs") with a physical surface that may be divided into a plurality of pixel regions (for instance, one or more photosensors and attendant control circuitry) configured to convert light into an electrical signal (charge, voltage, current, etc.). For convenience, pixel regions within an image sensor may also be referred to as image pixels ("IPs") and the aggregate of the pixel regions or image pixels will be referred to as the image sensor region. An image sensor IC typically will also include areas outside of the image sensor region, for example certain types of control or interface circuitry.
Most CMOS image sensors contain A/D (analog-to-digital) circuitry to convert pixel electrical signals into image data. The A/D circuitry can be one or more ADCs (analog-to-digital converters) located at the periphery of the image sensor region. Particularly for one-bit (binary) quantization, it is also possible to distribute one-bit ADCs within the image sensor region, one per IP or group of IPs.

Image sensor with a split-counter architecture


A modular surge protector is provided where only the number and types of modules needed are purchased and connected together by quick connect means. Generally, the modular surge protector includes a power distribution module, which is connected to a source of line current and one or more power supply modules, which snap to each other by the use of the quick connect means. Each of the power supply modules will have at least one power supply outlet and may also have a modem surge protector.

1. Field of the Invention
The present invention deals with outlet strips, and more particularly, with an outlet strip which may be in the form of a surge protector of the type commonly used to protect sensitive electrically operated equipment from line current surges. Most particularly, the invention deals with a modular outlet strip or surge protector having several types of sections which are quickly connected and disconnected by virtue of "quick connect" means provided on the modules.
2. Description of the Prior Art
Electrically operated equipment, practically since its inception, has been subject to surges of current over the power lines to which it is connected. These current surges can be caused by naturally occurring phenomenon, such as lightning strikes during thunder storms, which induce power surges in the power lines, or by man-made causes, such as sudden variations in the power being output from a generating station due to failures of components or other generators going on- or off-line.
Some types of electrical equipment have been developed which are more sensitive to line current surges than other types. Equipment which is particularly sensitive is in the nature of television sets, stereos, answering machines, and more recently, computer equipment. Ever since the advent of this sensitive electronic equipment, those in the art have sought a convenient and economical way to protect such electrical equipment from power surges. Many surge protectors are known in the prior art, and all operate by generally well-known principles, such as by capacitors connected between live and earth which discharge in the presence of a sudden surge of power and effectively short out that surge of power before it can reach the power supply cords plugged in to such surge protectors.
However, the outlet strips and surge protectors available in the prior art are generally of one type. They consist of a line cord with the surge protection, where used, connected across many outlets connected in parallel. Normally, the surge protectors have an on/off switch, an indicator light, and from six to ten receptacles. In many cases, only one or two receptacles are needed at a particular location, and the excess of receptacles provides for a bulky and inconvenient appliance.
Also, with the advent of computers with built-in telephone modems, a modem surge protector is many times needed in conjunction with a line current surge protector so that both the phone modem and the computer are protected from surges of current which may occur simultaneously. Modem surge protectors, in combination with line current surge protectors, have not been available until the time of the present invention. Thus, those skilled in the art have continued to search for solutions to the problems of how to provide a convenient, compact, and yet adaptable, surge protector.


A piezoelectric/electrostrictive device 10 includes a stationary portion 11; a thin-plate portion 12 supported by the stationary portion; and a piezoelectric/electrostrictive element 14 including a plurality of electrodes and a plurality of piezoelectric/electrostrictive layers arranged alternatingly In layers. The piezoelectric/electrostrictive device 10 is manufactured by the steps of forming a piezoelectric/electrostrictive laminate by alternatingly laminating laminar electrodes and piezoelectric/electrostrictive layers on a plane of a thin-plate member adapted to form the thin-plate portion 12, and cutting the thin-plate member and the piezoelectric/electrostrictive laminate. The cutting step is performed by advancing a wire member (wire saw) reciprocating in a direction parallel to the direction of lamination of the piezoelectric/electrostrictive laminate while holding the wire member substantially parallel to the direction of lamination. Thus, since the laminar electrodes are cut while being extended within corresponding layer planes, the degree of covering the end surfaces of the piezoelectric/electrostrictive layers decreases.

A piezoelectric/electrostrictive device of the above-mentioned type has been developed as an actuator for precision working; as an actuator for controlling the position of a read and/or write element (head) for reading and/or writing optical information, magnetic information, or like information; as a sensor for converting mechanical vibration to an electrical signal; or as a like device.
FIG. 25 shows an example of such a piezoelectric/electrostrictive device The piezoelectric/electrostrictive device includes a stationary portion 100; thin-plate portions 110 supported by the stationary portion 100; holding portions (movable portions) 120 provided at corresponding tip ends of the thin-plate portions 110 and adapted to hold an object; and piezoelectric/electrostrictive elements 130 formed at least on corresponding planes of the thin-plate portions 110, each piezoelectric/electrostrictive element 130 including a plurality of electrodes and a plurality of piezoelectric/electrostrictive layers arranged alternatingly in layers. An electric field is generated between electrodes of the piezoelectric/electrostrictive elements 130 to thereby extend and contract the piezoelectric/electrostrictive layers of the piezoelectric/electrostrictive elements 130, whereby the thin-plate portions 110 are deformed. The deformation of the thin-plate portions 110 causes displacement of the holding portions 120 (accordingly, displacement of the object held by the holding portions 120).
The piezoelectric/electrostrictive device of FIG. 25 is manufactured as follows. First, as shown in FIG. 26, a plurality of ceramic green sheets (and/or a ceramic green sheet laminate) are prepared. As shown in FIG. 27, these ceramic green sheets are laminated and then fired, thereby forming a ceramic laminate 200. As shown in FIG. 28, piezoelectric/electrostrictive laminates 210 each including a plurality of electrodes and a plurality of piezoelectric/electrostrictive layers arranged alternatingly in layers are formed on the surface of the ceramic laminate 200. The piezoelectric/electrostrictive laminates 210 are cut along cutting lines C1 to C4 shown in FIG. 29, thereby yielding the piezoelectric/electrostrictive device.
However, as shown in FIG. 30, an enlarged fragmentary front view of the lateral end surface of the thin-plate portion 110 and the piezoelectric/electrostrictive element 130, and in FIG. 31, an enlarged fragmentary, sectional view taken along line 1—1 of FIG. 30, when cutting is performed along the cutting lines C3 and C4 by use of a wire saw WS, ductility of electrodes 131 of the piezoelectric/electrostrictive element 130 causes the lateral end surface (cut surface) of each of the electrodes 131 to extend onto the lateral end surface of a piezoelectric/electrostrictive layer 132 located adjacently toward the direction of advancement of the wire saw WS (located adjacently downward in FIGS. 30 and 31). As a result, on the lateral end surface of the piezoelectric/electrostrictive element 130, the distance between the adjacent electrodes 131 is reduced. Furthermore, since the lateral end surface is exposed exteriorly, dust or the like tends to adhere thereto. As a result, it turned out that the adjacent electrodes are highly likely to short-circuit.

Piezoelectric/electrostrictive device and method for manufacturing the same


An insoluble anode is for the electrowinning of heavy metals from aqueous solutions which contain them, and for the electrolytic production of oxidizer halogenated salts.. The anode includes a copper bar acting as a bus bar (i.e., as a current-bearing bar), having vertical and horizontal holes through which fork-shaped elements, made from a bimetallic conductor, are inserted and fastened. A plurality of fork-shaped elements, made from the filamentary bimetallic conductor, coated by a catalytic layer of Pt and/or PbO.sub.2, act as an electrode with preferential oxygen development. A framework made from an insulating plastics material, is for supporting and stiffening the structure, and for the precise positioning of the anode inside the cell.

1. Field of the Invention
The extraction of heavy metals from the aqueous solutions of the salts which contain them, by electrolysis (electrowinning), requires the use of insoluble anodes which are good electrical conductors, and, simultaneously, are endowed with a high enough resistance to the electrolyte used and to the products from the relevant anodic reactions, and, finally, favor the development of oxygen.
2. Discussion of the Related Art
For those metals which are more commonly produced by this route: copper, nickel, manganese, zinc, cadmium, and so forth, the present art preferably uses anodes of bonded lead (with antimony, silver, calcium, and so forth).
In the usual sulfuric baths used to electrowin the above metals, the lead anodes get coated with a thin layer of lead sulfate which, by oxidation, is transformed into a layer consisting of Pb dioxide, which protects them from further corrosion and which, by being conductive, uses the development of O.sub.2 with a suitably low oxygen overvoltage.
In order to electrowin copper and nickel from the solutions of their sulfates, anodes have been used for many years, which consist of lead containing 6-8% of Sb, and which are consumed very slowly, unless chloride ions are present in the electrolyte. Unfortunately, the anode of Pb/Sb does not prevent Pb from polluting the cathode.
On the contrary, for zinc electrowinning, anodes of Pb with 0.5-1% of Ag are used, which are obtained by casting or lamination, and sometimes are provided with grooves to favor oxygen development and other times are provided with circular holes to favor the circulation of the electrolyte. The conduction of electrical current throughout the anode is secured by inserting the copper bar inside the body of the same anode, by melting. The resistance of these anodes to chemical attack by the electrolyte is undoubtedly good, and the useful operating life of such electrodes is often longer than 2-3 years.
A negative characteristic consists in that, owing to the presence in the zinc-containing solution, of a certain level of manganous ions, adhering scales of MnO.sub.2 are formed on the anode, which become thicker and thicker with time.
When these scales get detached, owing to natural processes, they release particles of PbO.sub.2 and/or of PbSO.sub.4, which increase the Pb level in the cathodic zinc.
Another common problem displayed by the lead anodes used in the above cited electrolyses, is the large amount of immobilized metal (the weight of an anode of the cells known from the prior art is always higher than 100 kg), and the costs deriving from the periodic restoration of the anodes. Furthermore, in many facilities, there is burdensome maintenance, due to the periodic removal of the scales (every 2-4 weeks), which is carried out in order to improve the quality of produced zinc, and reduce the cell voltage.
The production of lead by the electrolytic route is presently the focus of interest of the big metallurgical industry: the fluoroboric and fluorosilicic electrolytes, preferred owing to the higher quality of deposits which can be obtained, causes serious problems of resistance of the anodic material to arise.
E. R. Cole et al., U.S. Pat. No. 4,212,340, uses an anode constituted by a titanium sheet electrolytically coated with a thin-texture layer of PbO.sub.2, with a particularly compact structure.
M. Ginatta, U.S. Pat. No. 4,098,658, uses anodes made from graphite bars, which get naturally coated with PbO.sub.2, and are sheltered by it.
R. D. Prengaman et al., U.S. Pat. No. 4,236,978 uses anodes made from a graphite plate wrapped in a net made from a plastics material, which serves as a reinforcement for the deposit of PbO.sub.2, and counteracts the brittleness thereof.
All these types of anodes display a poor electrical conductivity, are rather brittle, and their useful operating life is rather short.
Also, the problems caused by the anodic materials used to produce oxidizer halogenated salts (at present, activated Ti or Pt are used), are not completely solved.

Insoluble anode for electrolyses in aqueous solutions

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