Vaccine displaying native antigenic loops of immunoglobulin E is critical for eliciting neutralizing anti-IgE antibodies. The embodiment of the invention enables the display of native antigenic IgE receptor-contacting loops as IgE B-cell vaccines via three steps of constraining methods. The loops of multiple antigenic B-cell epitopes can be molecularly grafted in, and conformationally constrained by the energy favorable flanking beta (b)-stands, i.e., the super b-strands identified in this invention. The constrained loops can be further stabilized in replacing a selective loop within the cystine knot peptide. These dual constrained antigenic loops are then integrated onto thermostable protein scaffolds, folded in the oxidative milieu that provides further conformational constraint and high yield.

Multifactorial pathogenic process of allergic asthma has posed a challenge in treating this disease. IgE-mediated immediate hypersensitivity exercises two subsystems in play: (i) Upstream CD4-T-cells/IgE+ B-cells subsystem: Allergen-specific Th2/Th17 CD4 T-cells contribute to the cytokine-mediated late phase reactions. In contrast, follicular CD4 (Tfh) T-cells provide essential help to stimulate IgE+ B-cells in the germinal center (GC) and peri-GC memory B-cells (Crotty, 2011, Ann. Rev. Immunol., 29: 621). (ii) Downstream IgE network subsystem: IgE produced by the upstream Tfh/IgE B-cells initiates and amplifies a complex network of the inflammatory cell circuit of extraordinary diversity, involving a web of high affinity IgE receptor (FceRI)-bearing mast cells, basophils, eosinophils, dendritic cells and Langerhans cells, and recently neutrophils. Mezzanine intercommunication layer: Histamine released by mast cells skews dendritic cells (DCs) for Th2 preference (Lambrecht, 2009, Immunity, 31:412). FceRI on mast cells mediated IgE-dependent antigen presentation, and further augmented Th2 development (Gong, 2010, BMC Immunol, 2010, 11:34).
IgE-mediated inflammation can cause the acute phase of immediate hypersensitivity, and the late phase reaction via a plethora of IgE-produced mediators; and the IgE-FceRI cellular network can in turn enhance Th2, and the Th2-mediated late and chronic phases of allergic asthma. To add further importance to IgE is the expression of FceRI on airway smooth muscle cells for the release of TNF-a during intractable asthma. Bronchial epithelial cells also exhibit FceRI, implicated in released IL-33 and TSLP that amplify Th2-mediated inflammation (Galli and Tsai, 2012, Nat. Med., 18:693).
Besides the IgE/FceRI network, low affinity IgE receptors (FceRII, CD23) are expressed on nearly all B-cells, which mediate IgE-dependent antigen presentation for Th2 (Schmaltz, 1996, Immunol. Invest., 25: 481). FceRII on epithelial cells plays a key role in retrograde transport of IgE immune complexes in the BAL fluid, which can therefore play a role in augmenting allergen/IgE complexes-induced inflammation on intraepithelial mast cells and airway dendritic cells. The expression of FceRI on IL17AR+ neutrophils strongly suggests a new synergy of IgE and Th17-mediated inflammation in allergic asthma (Galli and Tsai, 2012, Nat. Med. 18:693; Lambrecht et al., 2009, at. Med., 31: 412).
Thus, IgE is of paramount importance in the etiology of allergic asthma by affecting IgE-mediated inflammation, a plethora of cytokines by multiple cell types, and the profound impact on Th2 (Schmaltz, 1996, Immunol. Invest., 25: 481; Gong et al., 2010, BMC Immunol., 11:34). Thus a drug candidate such as IgE B-cell vaccine targeting IgE attenuates inflammation at the multiple levels, in particular ramification of the IgE-FceRI network. Blunting IgE and IgE receptors by neutralizing anti-IgE remains the central question in treating clinical allergic asthma.
To alleviate or cure the IgE-mediated allergic diseases, it is imperative to remove circulating and mucosal IgE. In this regard, the present treatment modality focuses on the removal of circulating IgE via passive administered monoclonal antibody, Xolair. Anti-IgE, Xolair that neutralizes the receptor-binding FG loop of IgE molecules alleviates IgE-mediated allergic asthma (Chang, 2000, Nat. Biotech., 18:157). In contrast to the passive monoclonal antibody-based passive vaccine, active IgE vaccines were proposed as another treatment modality to invoke actively produced anti-IgE that neutralizes host's IgE. One approach resides in random chemical coupling of synthetic IgE peptides to the immunogenic protein carriers as active vaccines (Brown et al., 2009, U.S. patent application Ser. No. 12/634,336).
Another embodiment of invention resides in engineering neutralizing IgE B-cell epitopes within thermostable, immunogenic protein scaffold in a single step internally (Chen, 2008, U.S. patent application Ser. No. 12/011,303; Chen, 2008, J. Immunol. Meth., 333: 10). The present embodiment of the invention represents constraining native IgE B-cell epitopes in two internal steps: into super b-strands, and further into the cystine knots; and then integrated in one external step onto the protein scaffold, of which the thermostability of the immunogenic protein scaffold is not compromised by foreign loop insertion.
Conception of a monospecific B-cell epitope and its conjugation as synthetic peptide unto an immunogenic protein was pioneered by Atassi, Lerner and Brown in the late 80's (Rowlands et al., 1983, Nature, 306: 694; Atassi, 1978, Immunochem., 15: 909). Most antigenic structure are presented as a loop constrained by the secondary alpha helix and beta sheet structure, and properly folded in the three dimensional array determined by favorable energetics.
Through extensive studies of numerous potential B-cell candidate epitopes, a B-cell loop antigenic epitope, taken out from the native constrained secondary and tertiary protein folding, is distorted in conformation. Such synthetic or recombinant peptides randomly conjugated to or integrated to a protein carrier backbone exhibited thermodynamically unpredictable, multiple distorted, random conformations (Rowlands, et al., 1983, Nature, 306:694). Synthetic or recombinant linear IgE B-cell epitopes without proper constraint remain in a state of complex random array without definable structural integrity. Constraining scaffold in supporting the antigenic loop is required for enabling functional native conformation with structural integrity.
In contrast, conception of constrained IgE B-cell epitopes prompts the step to constrain the IgE B-cell epitope directly in the thermostable protein scaffold, whereby functional native conformation of the constrained neutralizing IgE B-cell epitopes can be enabled by the constraint. The embodiment of this invention further improves the constraining platform in placing B-cell epitopes into the super constraining beta (b)-strands, and further strengthened by the thermostable cystine knots, and finally integrated onto another thermostable protein scaffold, engineered in an optimal oxidative folding chemical milieu. Hence the embodiment of the three improvements in this invention enables the native expression and structural integrity of the B-cell epitopes.
The embodiment of this invention with active, conformationally constrained IgE B-cell epitope vaccine improves over the passive neutralizing anti-IgE monoclonal antibody (Chang, 1995, U.S. Pat. No. 5,428,133): (i) Sustained circulating IgE-Xolair complexes in treated patients cause long-term IgE suppression. The regimen requires 36 to 54 week-long treatment in order to neutralize 95% circulating IgE. However, due to the small size of immune complexes, circulating IgE/IgG1 Xolair complexes assume a half-life of 21 days of IgG1 (IgE lasts only one day); consequently, total circulating IgE in the complexes are persistently elevated ˜100 fold as a result of treatment (Chang, 2010, Nat. Biotech., 18:157).
Active IgE B-cell vaccines embodied by this invention improve the safety margin by producing active polyclonal anti-IgE in the vaccinated recipients with appropriate length of protection based on the vaccination/booster regimen. The duration is controlled by reactivation of memory CD4 helper T-cells to the protein scaffold. Due to the polyclonal antibodies, the clearance of circulating and mucosal IgE and IgG complexes will be efficient via the liver sinusoids and Kupffer cells. Furthermore, as a murine human chimera antibodies, Xolair causes anaphylaxis in individuals (3.14/1000 patients vs 5.4 events/million shots), the constrained IgE B-cell active vaccine induces endogenous autologous anti-IgE indigenous to the host.
(ii) Xolair is inefficient in targeting the mission-critical pathogenic IgE in the lung. The passively delivered Xolair via the subcut route, sieved through afferent lymphatics into thoracic duct lymph into the general blood circulation, without permeating into the critical sites of the lung, central for allergic asthma. Allergen-specific IgE, secreted by IgE plasma cells present in induced peribronchus-associated lymphoid tissues (iBALT), into the surrounding lamina propria under the bronchial epithelial and endothelial cells, remains inaccessible to circulating anti-IgE monoclonal antibodies, whose delivery depends solely on inflammation-mediated changes in vascular permeability (Lambrecht, 2009, Nat. Med., 31: 412).
A further embodiment of this invention is that IgE B-cell vaccines delivered via mucosa route of immunization elicit anti-IgE in iBALT that neutralizes pathogenic IgE in situ in the iBALT. The FG super b-strands constrained IgE B-cell epitopes with or without Min-23 cystine knot constraint, integrated onto the immunogenic protein scaffold can be employed as IgE B-cell vaccines. B-cells recognizing native, constrained FceRIa receptor-binding IgE-B-cell epitopes are activated by CD4 helper T-cells reactive with CD4 helper epitopes on the immunogenic protein scaffold. Anti-IgE antibodies of the IgA and IgG classes can be released directly in mucosal secretion in addition to circulation via a preferred mucosal route of immunization with FDA-approved adjuvants, Toll like receptor (TLR)-7 agonist imiquimod, alum, lipid A-based adjuvant or TLR-9 adjuvant presently being evaluated.
The designed constrained IgE B-cell vaccines elicit polyclonal neutralizing anti-IgE of the IgG and IgA classes that inhibits IgE-mediated mast cell degranulation, and prevents airway inflammation and airway hyper-reactivity (Ahr) (Zuberi et al, 2000, J. I., 164: 2667). Thus engineering constrained IgE B-cell epitopes in the FG super b-strands and cystine knots, integrated onto the immunogenic protein scaffold yields can lead to new anti-IgE pan-allergy vaccines that can benefit asthmatics of different disease spectra through mucosal IgE targeting and neutralization.

Displaying native human IgE neutralizing FcepsilonRIa-contacting IgE B-cell epitopes by constraining super beta(b)-strands and cystine knots on thermostable protein scaffold


A charge coupled device having a CCIR/EIA mode conversion function includes: a plurality of VCCD regions formed in the direction of row, the VCCD regions having a predetermined interval from one another; a plurality of HCCD regions formed at the end of the VCCD regions in the direction of column; a plurality of photodetectors regularly arranged between the VCCD regions, the photodetectors generating signal charges according to an image signal; a plurality of vertical gate electrodes formed on the VCCD regions and the photodetectors in the direction of column, the vertical gate electrodes transmitting the signal charges of the photodetectors to the HCCD regions through the VCCD regions according to applied vertical clock signals; vertical clock signal generator for supplying a predetermined number of vertical clock signals; and a selecting portion for receiving vertical clock signals from the vertical clock signal generator, the selecting portion supplying the vertical clock signals to part of the vertical gate electrodes, or supplying disable signals instead of the vertical clock signals, according to an external selection signal.

The present invention relates to a semiconductor device, and more particularly, to a charge coupled device (CCD) having a CCIR/EIA mode conversion function.
Generally, for a CCD image sensor, there are a frame transfer mode, an interline transfer mode, and a frame interline transfer mode formed in combination with the aforementioned two modes, according to the reading mode of signal charges. The interline transfer mode is divided into an EIA (Electronic Industries Association) and CCIR (Consultative Committee International Radio) modes according to a scanning mode. FIGS. 1A and 1B show the optical black regions of the EIA and CCIR modes, respectively. In the EIA mode CCD having 250,000 pixels, effective pixels are 510(H).times.492(V), and its optical black region has the size of 25+2 horizontally (H) and 12+1 vertically (V). Accordingly, the total number of the pixels are 537(H).times.505(V). On the other hand, in the CCIR mode CCD having 290,000 pixels, effective pixels are 500(H).times.582(V), and its optical black region has the size of 30+7 horizontally (H) and 14+1 vertically (V). Accordingly, the total number of the pixels are 537(H).times.597(V).
FIGS. 2A and 2B are diagrams showing horizontal synchronous driving timings of the EIA and CCIR modes. In an EIA mode CCD, scanning is performed with 262(H) and 263(H) horizontal lines in even and odd fields for 1/60 seconds. In a CCIR mode CCD, scanning is performed with 312(H) and 313(H) horizontal lines in even and odd fields for 1/50 seconds. Accordingly, the vertical synchronous driving timings (not shown) of the EIA and CCIR modes are different from each other. Since the number of the effective pixels of the two modes in the horizontal lines are different from each other as shown in FIGS. 1A and 1B, their horizontal synchronous timings are also different from each other as shown in FIGS. 2A and 2B. In other words, the driving clock timings of the CCIR and EIA modes are different from each other.
In case that their driving timings are different from each other, if the driving clock timing of the CCIR mode is applied to the EIA mode, the timing is not enough for all the charges accumulated in the pixels of CCD used in the CCIR mode to be transmitted to a vertical charge transfer region. As a result, this affects image reproduction in CCD.
FIG. 3 is a layout of a conventional CCD. Referring to FIG. 3, gates are formed on a substrate which includes a plurality of photodiode (PD) regions, a plurality of vertical charge transfer (VCCD) regions for vertically transmitting image signal charges generated from the respective photodiodes, and a horizontal charge transfer region (HCCD) formed on one side of the VCCD region. That is, a plurality of first polysilicon gates 31 and second polysilicon gates 32 are alternately formed on the VCCD regions. First and second polysilicon gates 31 and 32 sequentially transmit the image signal charges generated from the photodiodes. Here, one side of second polysilicon gate 32 is formed to be superposed on the photodiode region, to be thereby used as a transfer gate.
In first and second polysilicon gates 31 and 32 formed on the VCCD region, a clock signal V.sub..phi.2 is applied to the first polysilicon gate 31, a clock signal V.sub..phi.1 to the second polysilicon gate 32, a clock signal V.sub..phi.4 to the next first polysilicon gate, and a clock signal V.sub..phi.3 to the next second polysilicon gate. By doing so, the first and second polysilicon gates transmit the image signal charges sequentially and vertically. That is, the transfer operation of the image signal charges is carried out in 4-phase clocking.
A plurality of first and second polysilicon gates 31a and 32a are formed on the HCCD region. First and second polysilicon gates 31a and 32a transmit the image signal charges, which are transmitted from the VCCD region in 2-phase clocking, to a sensing amplifier. This sensing amplifier converts the image signal charges into an image signal, what is output in turn. Clock signals H.sub..phi.1 and H.sub..phi.2 are alternately applied to first and second polysilicon gates 31a and 32a formed on the HCCD region. By doing so, first and second polysilicon gates 31a and 32a sequentially transfer the image signal charges.
As described above, in the conventional CCD, the potential level of the image signal charges generated from the respective pixel regions is changed according to the clock signals V.sub..phi.1, V.sub..phi.2, V.sub..phi.3, and V.sub..phi.4, and then the image signal charges are transmitted vertically. This image signal charges are transmitted to a floating gate region according to the clock signals H.sub..phi.1 and H.sub..phi.2 and converted into an analog signal through the sensing amplifier. The vertical and horizontal transfer of the image signal charges of the conventional CCD is carried out according to the respective transfer clock signals. However, in case that the CCIR mode CCD is used for the EIA mode, the driving clock timing of the EIA mode is faster than that of the CCIR mode. Accordingly, compared with the CCD used in the EIA mode, charges accumulated in many pixels of the CCD used for the CCIR mode cannot be transmitted to the VCCD regions. Here, the charges, which can not be transmitted to the VCCD region, are transmitted according to the next clock signal. These charges are overlapped with the charges of the previous pixel. As a result, images are overlapped with each other during image display.
The above-described conventional CCD has the following problems. Since the number of pixels of CCD according to the respective scanning modes are different from each other, one kind of CCD cannot be used in both EIA and CCIR modes. Accordingly, it is required that the CCD is changed according to its scanning mode.

Charge coupled device having CCIR/EIA mode coversion function


A remote fueling system is provided. The system comprises a wellbore servicing equipment unit comprising an internal combustion engine, a fuel tank coupled to the internal combustion engine, a fuel distribution channel, a fuel level sensor component, a fuel level indicator, and a fuel level indicator control box. The wellbore servicing equipment is mounted on a trailer upon which the wellbore servicing equipment is transported to the wellbore. The fuel level sensor component senses a fuel level inside the fuel tank. The fuel level indicator indicates a fuel level status of the fuel tank to remote fueling personnel at a standoff distance. The fuel level indicator control box is coupled to the fuel level sensor component and to the fuel level indicator and commands the indication presented by the fuel level indicator based on the fuel level inside the fuel tank sensed by the fuel level sensor component.

Wellbore servicing operations may include cementing a casing in the wellbore, perforating the casing at one or more production zones, fracturing a formation to enhance flow of hydrocarbons from a production zone, acidizing a formation to enhance flow of hydrocarbons, and other like operations. Wellbore servicing operations may be performed by a specialized wellbore servicing company engaged by the company that is managing the subject well. The wellbore servicing company may transport wellbore servicing units, for example high pressure pumping units, to the wellbore location on tractor-trailers and/or on bodyload unit vehicles specialized for transportation to and operations at remote locations. Wellbore locations may be in remote areas lacking services and utilities that may be commonly available in developed urban and/or suburban areas.


An optical fiber has a Raman gain efficiency with a pump power at 1450 nanometers of equal to or more than 4 m/W, and a ratio of a nonlinear parameter γ at a wavelength of 1550 nanometers to the Raman gain efficiency with a pump power of 1450 nanometers is equal to or less than 3.

1) Field of the Invention
The present invention relates to an optical fiber, an optical fiber module, and a Raman amplifier for high-speed optical communications.
2) Description of the Related Art
Raman amplifiers are receiving more attention as an amplifier capable of light amplification in a desired wavelength band and realizing a gain over a bandwidth as broad as 100 nanometers. Any silica-based optical fiber can be employed as an optical fiber used as an amplifying medium of the Raman amplifier. However, as a Discrete Raman amplifier, an optical fiber with Raman gain efficiency (GR/Aeff, where GR is Raman gain coefficient and Aeff is effective area) of 6.5 m/W or more is generally used, and a gain of 20 decibels or more is obtained with a pump light of about 500 milliwatts.
Although the conventional optical fiber achieves the gain of 20 decibels or more with the pump light of about 500 milliwatts, it is accompanied by a large nonlinear phase shift simultaneously, and as a result, communication quality is deteriorated due to a waveform distortion of a signal light, which is an adverse factor that hinders high-speed optical communications.
The nonlinear phase shift of a signal light in an optical fiber with a length L is expressed by
            ΔΦ      NL                  (      L      )        =                    2                π                                                            n          2                                      λ          S                                  A          eff                                        ∫        0        L                                                P            S                                          (            z            )                                            ⅆ          z                    where Ps is a power of the signal light, λs is a wavelength of the signal light, n2 is a nonlinear refractive index of the optical fiber, and (2π/λ)·(n2/Aeff) is a nonlinear parameter γ of the optical fiber. The above equation tells that, as the nonlinear parameter γ of the optical fiber becomes larger, the nonlinear phase shift of a signal light becomes larger and the nonlinear optical phenomenon such as a self phase modulation or a cross phase modulation becomes easier to occur. Since the nonlinear parameter γ is proportional to the Raman gain efficiency, if the Raman gain efficiency of a high nonlinear optical fiber is increased in order to increase the efficiency of the Raman amplifier, the nonlinear parameter γ is also increased, so that a large nonlinear phase shift occurs.
In other words, a nonlinear phase shaft is more likely to occur as an Aeff or a mode field diameter is small, and a germanium concentration in a center core of the optical fiber is high. Since an optical fiber with a large Raman gain generally has a large nonlinear refractive index n2, a large nonlinear phase shift is caused at the same time.

Optical fiber, optical fiber module, and Raman amplifier


A laser diode with a single-transverse-mode output having a laser cavity comprising both single-mode and multi-mode waveguide portions, and a method of manufacturing such a laser diode are disclosed. There are a pair of single transverse waveguide regions at opposite ends of a multi-mode waveguide. The multi-mode waveguide is a 1×1 multi-mode interference waveguide, with a wider width than the single-mode portions. Use of the multi-mode region improves the power output, threshold current density, and overall efficiency in comparison to a similarly constructed laser diode in which the entire laser cavity is single-mode.

1. Field of the Invention
The present invention relates to a laser diode and a manufacturing method of the same, and more particularly to a single-mode laser diode comprising a light waveguide including a multi-mode waveguide region and a manufacturing method of the same.
2. Description of the Related Art
Opto-electronics technologies have been utilized and developed in various fields such as the information input/output technologies typified by compact discs (hereinafter referred to as CDs) and the optical communication technologies using optical fibers, and so on. Laser diodes, (hereinafter referred to as LDs), have been developed as devices which support these opto-electronics technologies. For example, LDs of near infrared band or visible band are used for CDs and LDs of long wave band are used for optical communications. As described above, various kinds of LDs contribute to the opto-electronics technologies.
There are various structures of LDs. Among waveguide type LDs, the waveguide type LDs having a waveguide which obtains a so-called single-transverse-mode light are generally used. Concerning CDs, in order to increase the capacity of information, it is important to increase the recording density. And it is necessary to use single-transverse-mode light to increase the recording density. Moreover, with regard to optical communications, there is a problem that the multi-mode signal light is not suitable for long distance communication because of the influence of multi-mode dispersions. For this reason, a waveguide type LD which emits single-transverse-mode light is generally used in both the field of the information input/output and the field of the optical communications.
In order to obtain this single-transverse-mode light, from the waveguide of the LDs, a single-transverse-mode waveguide which has a narrow waveguide width to cut off the multi-mode light is generally used. More concretely, in the single-transverse-mode waveguide, the width of the active layer in the waveguide of the LD is limited in the range of about 2 to 4 μm. Therefore, an electric current capable of being injected into the LD is limited to a relatively small value so that there is a limitation to an output of light.
In order to allow a high injection electric current and to enhance a saturation light output level, one of the easiest ways is to widen the waveguide width of the LD. However, as described above, since there is the limitation that the waveguide width must be relatively narrow in order to realize the single-transverse-mode waveguide, a technological restriction for achieving a high output performance of the LDs exists.
In order to solve the foregoing problems, various kinds of methods have been proposed. A mode-filter integrated multi-mode LD is reported in IEEE Journal of Quantum Electronics Vol. QE-23 No. 6, 1987, pages 730-737, by Patrick Vanwikelberge et. al. ( hereinafter referred to as the first prior art). In this multi-mode LD, a main light excitation region is constituted by a multi-mode LD having a wide waveguide width, resulting in an increase in a saturation light output performance.
As another way, a flare-shaped LD is reported in Electronics Letters Vol. 32, No. 24, 1996, pages 2277-2279, by M. Sagawa et al. (hereinafter referred to as the second prior art). This LD has a structure in which a waveguide width in its one end and the waveguide width becomes broader toward its other end showing a flare shape. Since the waveguide width in its broader end is broader than conventional single-transverse-mode waveguides, the light output performance is increased. In addition, since the mode of the output light is controlled by the single-transverse-mode waveguide region at the narrow end, the foregoing LD can be constructed such that it can keep the single-transverse-mode light in spite of the broader width in its other end, by forming it to the desirable flare shape.
Moreover, as another way, a Phase-locked LD array is reported in Applied Physics Letters Vol. 60, No. 6, 1992, pages 668-670, by L. J. Mawst et. al. (hereinafter referred to as the third prior art). This LD array has a plurality of LDs, for example, 20 LDs, which are integrated by arranging them perpendicular to the direction of the its light waveguide at certain intervals and the LDs are allowed to resonate with each other, thereby finally achieving a high single-transverse-mode output.
In the first prior art, though the multi-mode waveguide region excites not only the single-transverse-mode light but also primary and secondary lights, the single-transverse-mode light can be obtained by removing the primary and secondary lights by mode filters. Since light energies of the primary and secondary lights do not contribute to the single-transverse-mode light output of the LD, there is a problem that an electric/light conversion efficiency is low compared to the conventional single-transverse-mode LD.
From the view point of manufacturing the LD, the second prior art involves a disadvantage of difficulty in forming a desirable flare shape. Specifically, in the case that the length of the LD involves a little error or the broader end of the waveguide is not formed exactly according to the design due to an error in manufacturing, the flare shape is no longer the most desirable one. In this case, the desired characteristics of the LD can not be obtained.
The third prior art has a complicated structure and involves a difficulty in manufacturing so that it is difficult to manufacture the LD array with a high yield. Moreover, in the third prior art, a structural tolerance to satisfy the resonance conditions is severe, that is, the allowable range of the error of the third prior art is narrow, so that it is difficult to manufacture the LD array with a high reproducibility.
As described above, the allowable injection electric current into the LD having a narrow waveguide width to obtain the single-transverse-mode light, which has been heretofore used in general, is limited to a small quantity, so that there is a problem of limitation of the output of the LD. The three prior arts that have been proposed in order to solve these problems involve the problems that it is difficult to obtain the high electric/light conversion efficiency, the LD can not be manufactured with a high reproducibility, the manufacturing tolerance is severe, and the structures are complicated.

Single-transverse-mode laser diode with multi-mode waveguide region and manufacturing method of the same


A surgical module is supported by manipulators that are removably attached to the surgical module. The surgical module may enable operation of surgical tools by providing an integration between actuating mechanisms of the manipulators and actuating mechanisms of the surgical tools. Alternatively or additionally, the surgical module may enable operation of the surgical tools by providing physical access for deploying surgical tools that are operatively connected to the manipulators.

The present disclosure relates generally to medical and robotic devices, systems, and methods.
Minimally invasive medical techniques typically reduce the amount of extraneous tissue that is damaged during diagnostic or surgical procedures, thereby reducing patient recovery time, discomfort, and deleterious side effects. Because the average hospital stay for a standard surgery is typically significantly longer than the average stay for an analogous minimally invasive surgery, increased use of minimally invasive techniques can substantially reduce hospital costs each year.
While many of the surgeries performed each year in the United States could potentially be performed in a minimally invasive manner, only a portion of the current surgeries use these advantageous techniques due to limitations in minimally invasive surgical instruments and the additional surgical training involved in mastering them. Thus, there is a need for improved devices, systems and related methods for minimally invasive surgery.

Surgical platform supported by multiple arms


A method of performing speech synthesis, includes encoding character embeddings, using any one or any combination of convolutional neural networks (CNNs) and recurrent neural networks (RNNs), applying a relative-position-aware self attention function to each of the character embeddings and an input mel-scale spectrogram, and encoding the character embeddings to which the relative-position-aware self attention function is applied. The method further includes concatenating the encoded character embeddings and the encoded character embeddings to which the relative-position-aware self attention function is applied, to generate an encoder output, applying a multi-head attention function to the encoder output and the input mel-scale spectrogram to which the relative-position-aware self attention function is applied, and predicting an output mel-scale spectrogram, based on the encoder output and the input mel-scale spectrogram to which the multi-head attention function is applied.

Text-to-speech (TTS) technology is advancing as it moves from hidden Markov models (HMM) to neural networks (NN). For either an HMM or NN-based TTS system, a framework is composed of three major components: 1) a complex "front-end" module to analyze raw text into a linguistic feature. 2) a "back-end" module to learn and transform linguistic features to acoustic features, and 3) a "vocoder" to reconstruct speech waveform from the generated acoustic features. The "front-end" module is language dependent, and designing a good "front-end" may require expert knowledge on a specific language as well as great time and effort.
Recently, successful applications of an attention-based sequence-to-sequence (seq2seq) model are outperforming conventional structures including several end-to-end speech synthesis systems. The attention mechanism can jointly learn alignments and perform linguistic-feature-to-acoustic-feature mapping, to train and infer from a "text end" to a "speech end" as a whole.
The emergence of these seq2seq-based speech synthesis models such as Tacotron discards an independently-designed text analyzer, and replaces traditional aligned linguistic-frame-to-acoustic-frame mapping networks by an encoder-decoder paradigm. The basic idea of Tacotron is to use recurrent neural networks (RNNs) to encode a text symbol sequence and then generate a variable length output acoustic feature sequence with decoder RNNs. The encoder and decoder are connected through a soft attention mechanism. Because such recurrent architecture relies on the entire past information during hidden state computations, a fully convolutional neural networks (CNNs)-based seq2seq framework has been proposed to enable parallel training. Compared to RNNs, convolutions collect local contexts by kernels, and catch long-range dependencies by a large receptive field created by stacking CNN layers. This kind of architecture is successfully used in speech synthesis areas such as Deep Voice 3 and Deep Convolutional TTS (DCTTS).
More recently, a more parallelizable architecture named Transformer has been proposed to model global dependencies between inputs and outputs, whilst address a vanishing gradients problem of RNNs. Transformer is solely based on attention mechanisms to achieve seq2seq modeling, which requires a minimum number of sequential operations during training. With self-attention, Transformer can attend whole sequence information at each position. Furthermore, self-attention has a shorter path length between long-range dependencies than RNN and CNN, which makes it easier to learn. Almost at the same time of this work, the Transformer architecture has been successfully applied to a speech synthesis task, which shows a good capability of generating speech with self-attention.
However, there are also shortcomings in a self-attention mechanism. Firstly, recent research points out that there is no position guidance in self-attention, so extra position encoding is injected to handle sequential information. Secondly, a weighted averaging operation in self-attention may lead to dispersion of a distribution of attention, which results in overlooking a relation of neighboring signals. In speech synthesis experiments, even by adding position encoding in a self-attention-based TTS system, a computer may be found talking nonsense from time to time. Thirdly, full self-attention may not perform as well as RNNs when modeling underlying hierarchical structures in many tasks.

Enhancing hybrid self-attention structure with relative-position-aware bias for speech synthesis


A method for designing a profile extrusion die is based on an analogy that exists between membrane deflection under pressure and low Reynolds number pressure driven fluid flow. The analogy is used to predict the relative shape of the die to correct for die swell or die contraction. The application of the analogy takes into consideration the characteristics of the extruder, the operating conditions, and the extrudate composition.

1. Field of the Invention
The present invention relates generally to profile extrusion die hardware. It relates particularly to a method for designing a profile die for polymer extrusion.
2. Description of the Related Art
Extrusion is the process of forcing material through a die having an extrusion profile, to form a product having a cross section that matches the extrusion profile. The length of the extruded product is determined by the amount of material forced through the die. The cross section of the extruded product is determined by the shape of the profile, which is defined by the die designer.
The design of flat plate dies (also called profile or orifice dies) is affected by many variables, including the composition of the viscoelastic extrudate, as well as the operating parameters of the extruder machine. For low Reynolds Number flows of viscoelastic polymers, the resulting extrudate can swell or shrink anywhere from 10% to 300% depending upon the die shape, material composition, extruder screw speed, temperature, etc. Chris Rauwendaal states in Polymer Extrusion (published by Hanser, New York, 1986), "A good die designer must anticipate the amount of uneven swelling, and design the flow channel accordingly. This process is a very difficult task and the determination of the flow channel geometry is often done by a 'trial and error' process. Determination of the proper flow channel geometry to minimize uneven swelling by engineering calculations is generally not practical."
The objective of the subject invention is to present a new method for designing profile extrusion dies. The method is based on an analogy that exists between membrane deflection under pressure and low Reynolds Number pressure driven fluid flow die swell. Sir Horace Lamb (Hydrodynamics, Dover, New York, 1932) comments on an analogy between the theory of the steady motion of a viscous liquid in two dimensions and that of the flexure of an elastic plate. However, in spite of the fact that this analogy was recognized many years ago, and designing profile dies for extrusion of rubber and other materials has been a problem for even longer, to date no one in the art has recognized that this analogy might beneficially be applied to polymer extrusion dies where swelling or contraction is a problem.
Die designers typically use experience-based rules to derive profile extrusion die designs. After designing an initial profile extrusion die, the design is implemented in a trial extrusion process. The designer evaluates the resulting extrusion to determine whether the die design produced the desired result. If not, then the die dimensions are modified and tested in another extrusion process. Often, many iterations of modifying and testing the die are necessary before arriving at a design that yields the desired result. This current methodology is time-consuming and requires a great deal of experience-based judgement and die modification. In addition, the designer must modify the die and re-initiate the process every time product dimension requirements change, or when a new material is to be extruded. Much of the problem is caused by the fact that the extruded material stores energy while under pressure, and then swells as it exits the die. The expansion of the extrudate is generally unpredictable for complex profile geometries, and may vary from 10% for some polymers to 100% for some rubber materials. Consequently, extrusion die design is often slow and costly, and designers resist the introduction of new materials to the profile extrusion market.
It would be of great benefit to the extrusion industry to provide a method which would decrease much of the iterative guesswork and reliance on experience currently required by the die design process. Die designers would prefer for profile die design to be less of an art, and more of a science. To that end, there have been some significant developments in the past few years, but nothing that has fully solved the iterative design problem, and nothing of the nature of the subject invention.
Recent inventions by Wang et al and Huang, et. al., particularly have attempted to address this problem. Patents by Wang (U.S. Pat. Nos. 5,608,637, 5,926,393, and 6,246,918) describe methods by which a slit die is used to determine properties of particular polymer resins, information sheets are derived from the acquired properties, the information is stored in a computer, and the data is used to design a profile die. Patents by Huang (U.S. Pat. Nos. 5,974,850 and 6,153,131) describe the design of pockets in thick dies to increase extrusion speed, and the development of extrusion processes for existing profiles, given the properties of the resin to be extruded. To date, no inventions successfully address the problem of designing an extrusion profile based on polymer properties and desired product dimensions, such that die swell for complex profile shapes can be effectively predicted.

Method for designing a profile die for polymer extrusion


A marine muffler adapted with an internally tunable sound suppression structure is adaptable to different configurations thereby allowing for structural adjustments to optimize sound suppression and minimize backpressure for particular engine and exhaust conditions. A muffler housing defines an interior volume and includes an exhaust inlet and outlet. The outlet has a reduced diameter as compared with the inlet such that the exhaust gas accelerates through the muffler. An inclined baffle partitions the interior volume into a lower chamber in communication with the exhaust inlet and an upper chamber in communication with the exhaust outlet. Exhaust ducts attached to each side wall penetrate the baffle thereby placing the upper and lower chambers in fluid communication. A corrugated partition divides each exhaust duct into a plurality of non circular conduits. The muffler may be tuned by selectively capping one or more conduit outlets.

1. Field of the Invention
The present invention relates generally to marine exhaust systems for use with internal combustion marine engines, and more particularly to an improved marine muffler having an inclined baffle assembly and tunable pulse attenuation exhaust conduits that provide improved exhaust noise silencing.
2. Description of Related Art
Marine vessels are typically configured with a propulsion system powered by an internal combustion engine mounted within the vessel hull. Exhaust generated by the engine is commonly combined with cooling water and routed through exhaust conduit to the stern of the vessel via one or more exhaust ducts where the exhaust is discharged through one or more exhaust ports formed in the transom. One or more mufflers are installed within the exhaust duct(s) to silence noise associated with the engine and exhaust gases.
A variety of structures are known in the background art for use in silencing marine exhaust noise. The present inventor has invented a number of novel marine exhaust components that have greatly improved the silencing and efficiency of marine exhaust systems. Among those inventions developed by a named inventor for the present invention are the following:
U.S. Pat. No.Entitled4,918,917Liquid Cooled Exhaust Flange5,196,655Muffler for Marine Engines5,228,876Marine Exhaust System Component Comprising a HeatResistant Conduit5,262,600In-line Insertion Muffler for Marine Engines5,444,196In-line Insertion Muffler for Marine Engines5,504,280Muffler for Marine Engines5,616,893Reverse Entry Muffler With Surge Suppression Feature5,625,173Single Baffle Linear Muffler for Marine Engines5,718,462Muffler Tube Coupling With Reinforcing Inserts5,740,670Water Jacketed Exhaust Pipe for Marine Exhaust Systems.6,564,901Muffler for Marine Engine7,581,620Marine Muffler with Angularly Disposed Internal Baffle7,905,322Marine Muffler with Angularly Disposed Internal Baffle7,942,238Marine Muffler with Angularly Disposed Internal Baffle8,246,403Marine Water Drop Muffler8,651,907Water Jacketed Marine Exhaust Components HavingMultiple Stream Spray Ring Configurations
In U.S. Pat. No. 5,262,600, the first named inventor herein disclosed an in-line insertion muffler for marine engines employing a first housing encompassing a second housing which is partitioned by an angularly disposed inner planar baffle that has proven extremely effective in reducing engine noise. In U.S. Pat. No. 5,444,196, the first named inventor herein disclosed an improved version of the in-line muffler having a corrugated sleeve disposed between in the first and second housings. In U.S. Pat. No. 5,625,173, the first named inventor herein disclosed a single baffle linear muffler with an angularly disposed baffle that may be planer, convex, or concave. In U.S. Pat. No. 7,581,620, the first named inventor herein disclosed a marine muffler comprising an elongate cylindrical housing having an inlet and an outlet, and an internal volume partitioned by an angularly disposed internal baffle into a lower chamber in communication with the inlet and an upper chamber in communication with the outlet. A centrally disposed duct passes through the baffle to allow exhaust gas and exhaust cooling water to flow from the lower inlet chamber to upper outlet chamber.
The various linear mufflers made in accordance with the above-referenced patents have achieved tremendous success and widespread acceptance within the marine industry. Such muffler systems have been successfully installed on a wide variety of marine vessels having engines in excess of 1,000 horsepower. Due to the myriad engine packages and exhaust configurations, there exists a need for advancements in marine mufflers that allow for structural adjustments to the muffler to optimize sound suppression and minimize backpressure for specific engine makes and models.

Velocity accelerating marine muffler with pulse attenuation tuning


A test apparatus 10 for testing the diameter of oilfield tubulars having various nominal diameters includes a machine frame 12 for successively receiving the axially movable tubulars, and upper and lower radially opposing carriages 16 and 18 each movable relative to the machine frame. First and second light generating sources 24 and 26 are each mounted on a respective carriage and transmit a wide light beam directed to intersect radially opposing sides in the oilfield tubular, such that the width of each light beams is reduced by engagement with the tubular. First and second light detectors 28 and 30 are each mounted on the carriages and are positioned for detecting the position of the reduced width light beams relative to the carriages and generating test signals in response thereto. Computer 32 is provided for receiving test signals from the sensors and generating a tubular diameter test measurement in response thereto. The test apparatus includes upper and lower optical shutters 52 and 54 each mounted on the carriages and movable from an active standardization check position to an inactive position. Each shutter has an opening therein for transmitting a preselected reduced width light beam past the shutter. Micrometer 56 is provided for measuring a radial spacing between the first and second carriages and generating a carriage spacing signal in response thereto. According to the method of the invention, a specific test specimen 42, 44 is positioned for calibrating the spacing between the carriages. The carriages are then moved to a standardization position and shutters are used to perform a standardization check on the equipment. Assuming this standardization check is passed, the shutters are moved to an inactive position and tubulars then tested for diameter and ovality. Significant savings are realized by not having to recalibrate the test apparatus for each size nominal diameter tubular being tested, and by not requiring a test standard for each size tubular capable of being tested.

Non-destructive testing equipment has been used for decades to detect material defects in oilfield tubulars. Advancements in ultrasonic and electromagnetic testing techniques have resulted in equipment which is able to reliably detect material defects at rates in the range of from 40 to 400 thirty-foot joints of pipe per hour. Such high speed testing equipment has reduced the cost of non-destructive testing and, equally important, has reduced the lead time between a pipe order to an inspection yard and the delivery of inspected oilfield tubulars to the well site.
Equipment has been used for detecting irregularities in the outside diameter and ovality of oilfield tubulars ever since these tubulars were used in oilfield operations. In spite of technological advances, many oilfield tubulars are still manually checked with O.D. calipers. While these manual checking operations may be satisfactory when the customer requests that only random checks be made on a lot of oilfield tubulars, this technique becomes too expensive and time consuming when numerous axial locations along the length of each tubular are to be checked for outer diameter and ovality conformance. Increased emphasis is being placed on oilfield tubular diameter and ovality tolerance, particularly for deep offshore wells where tubulars are exposed to corrosive environments. Accordingly, manual checking of oilfield tubular diameter and ovality is practically not an option for these oilfield tubulars.
One technique for more rapidly testing oilfield tubular diameter utilizes a pair of light beams each directed traverse to the axis of the tubular. A pair of relatively wide light beams strike radially opposing sides of the tubular, such that the tubular material blocks light to alter the width of each beam. The spacing between the reduced width beams is accordingly a measure of the diameter of the oilfield tubular. Optical systems thus offer significant advantages in being able to test oilfield tubular diameters at a rate commensurate with medium speed non-destructive equipment systems used for testing oilfield tubulars.
Significant problems remain, however, before oilfield tubular diameter and ovality can be rapidly checked at higher speeds desired by both inspection service companies and their customers. One problem with existing optical testing systems is the time required to process the data from detectors which sense the presence of light and thus generates raw data indicative of the spacing between the reduced width light beams. Significant delays are commonly experienced between diameter and ovality tests on oilfield tubulars utilizing existing optical technology and the generation of meaningful data which indicates to the testing operator the information necessary to pass or fail the tubular. Also, those skilled in the art recognize that orders to inspection yards are typically performed on a first-in/first-out basis, that successive orders are rarely for the same pipe size, and that a single inspection order may require the testing of different oilfield tubular sizes. Filling an inspection order thus commonly requires one or more recalibrations of the testing equipment. A test standard corresponding to the specific size tubular to be tested is thus positioned within the testing equipment, and the equipment is then calibrated or "zeroed" to that test standard. The optical testing equipment thus measures positive or negative variations from the test standard when performing the O.D. test on a specific size oilfield tubular. The printout to the inspection operator thus indicates the positive or negative variation of the tubular diameter compared to the test standard.
The above technique has several major drawbacks. A significant amount of time is required to recalibrate the equipment each time a different size oilfield tubular is to be tested. Since it is preferable to test oilfield tubular diameter and ovality at the same time each tubular is being checked for material defects with non-destructive testing equipment, the time required to recalibrate the optical equipment for checking a tubular diameter slows down the overall inspection process. Also, each inspection yard must maintain a complete set of different oilfield tubular diameter test standards to be used to calibrate the optical inspection equipment. These tubular diameter test standards must be carefully maintained, since any variation of the test standard will lead to incorrect diameter variation measurements.
The disadvantages of the prior art are overcome by the present invention, and improved methods and apparatus are hereinafter disclosed for the high speed measurement of oilfield tubular diameter and ovality. The present invention significantly reduces the time required to standardize equipment between different tubular diameter runs, and allows oilfield tubular diameter and ovality measurements to be conducted and the data output in real time at tubular feed through rates commensurate with high speed non-destructive testing equipment.

Method and apparatus for high speed measurement of oilfield tubular diameter and ovality


In a process of pouring molten metal under pressure into a die cavity C through a pouring gate G, a molten metal pressure in a part of the die cavity to be filled with the molten metal later than the rest thereof, or in the vicinity of the part, is detected by a first pressure sensor S5, and a cavity backpressure in the part of the die cavity to be filled with the molten metal later than the rest thereof, or in the vicinity of the part is detected by a backpressure sensor 12. Then, a pouring rate of the molten metal is controlled in accordance with changes in the respective detected pressures.

1. Field of the Invention
The present invention relates to a casting method based on a pressure casting process, and a casting apparatus for use in this casting method.
2. Description of the Related Art
As is generally known, a casting process of pouring molten metal or molten alloy (hereinafter referred to occasionally as "molten metal" for brevity) under pressure into a die cavity (hereinafter referred to occasionally as "cavity" for brevity), so-called pressure casting process, e.g. a die casting process, is often used, for example, in casting where light metal or light alloy, such as aluminum or its alloy, or magnesium or its alloy, are used as a material.
However, even the casting using the pressure casting process still involves a problem about defects occurring at a portion of molten metal located in a part of the die cavity relatively far from a pouring gate (for example, typically seen in the most downstream portion of molten metal relative to the pouring gate), such as: so-called "shrinkage cavity" occurring when the portion has a large thickness, so-called "misrun" occurring when the portion has a small thickness, etc. Generally, such defects are caused by the fact that a pressure of molten metal is not effectively transmitted to the portion located a certain distance or more from the pouring gate, or that air in the die cavity is trapped by or entrained into molten metal.
The insufficient transmission of a molten metal pressure in a portion located a certain distance or more from the pouring gate generally arises from deterioration of dies, fluctuation in surface temperature of dies due to changes in working temperature or cooling conditions (amount and/or temperature of cooling water, etc.) of the dies, fluctuation in temperature and/or chemical contents of the molten metal, and/or other factors. The entrainment of air into the molten metal generally arises from fluctuation in molten metal temperature, chemical contents of the molten metal or occluded gases, lowering in degree of evacuation due to deterioration of die-sealing materials, and/or other factors. It is also known that an excessive pouring rate of molten metal into the die cavity is liable to cause the entrainment of air.
While the occurrence of casting defects due to insufficient pressure (or insufficient filling) or air entrainment can be drastically reduced by exactly detecting and controlling the above various factors, the practical use of such measures has not been achieved because of a lot of costs required therefore.
In connection with the above problems about the pressure casting, for example, Japanese Patent Laid-Open Publication No. 2002-103014 proposes a metal injection molding method, which detects a molten metal pressure in a molten metal flow channel on its downstream side relative to a die cavity, and then sets a pouring rate (injection speed) of molten metal into the cavity in accordance with the change of pressure in the molten metal flow channel.
In order to prevent the occurrence of casting defects due to insufficient filling, it is most desirable that the filling of molten metal is completed before the molten metal finishes solidifying, i.e. when the molten metal is still in its fully molten state (i.e. liquid phase) or at least in its semi-molten state (i.e. mixed phase of liquid and solid), to assure the good states of "run" (i.e. to prevent the occurrence of misrun) and to allow the pressure of the molten metal to be transmitted to every distal end of a cast article. Therefore, it is required to fill a die cavity with molten metal at a high pouring rate to a maximum extent. On the other hand, in order to prevent the occurrence of casting defects due to air entrainment, it is also required to keep the pouring rate of the molten metal into the die cavity from excessively high level.
That is, an excellent cast article free from casting defects due to insufficient filling or air entrainment can be obtained, only if a condition for filling a die cavity with molten metal is set in such a manner that the above two conflicting factors are simultaneously satisfied.
However, the aforementioned prior art designed to set the injection speed in accordance with only the detected molten metal pressure can facilitate to suppress the occurrence of defects due to insufficient filling, but has difficulties in stably preventing the occurrence of defects due to air entrainment.
Accordingly, as a solution of the above problems, a casting method and a casting apparatus which simultaneously suppress both the occurrence of defects due to insufficient filling of molten metal and the occurrence of defects due to air entrainment has been desired.


An expansion engine operating on a Brayton cycle which is part of a system for producing refrigeration at cryogenic temperatures that includes a compressor, a counter-flow heat exchanger, and a load that may be remote, which is cooled by gas circulating from the engine. The engine has a piston in a cylinder which has nearly the same pressure above and below the piston while it is moving. Low pressure on a piston drive stem provides a force imbalance to move the piston towards the warm end.

1. Field of the Invention
This invention relates to an expansion engine operating on the Brayton cycle to produce refrigeration at cryogenic temperatures.
2. Background Information
A system that operates on the Brayton cycle to produce refrigeration consists of a compressor that supplies gas at a discharge pressure to a counterflow heat exchanger, from which gas is admitted to an expansion space through an inlet valve, expands the gas adiabatically, exhausts the expanded gas (which is colder) through in outlet valve, circulates the cold gas through a load being cooled, then returns the gas through the counterflow heat exchanger to the compressor.
U.S. Pat. No. 2,607,322 by S. C. Collins, a pioneer in this field, has a description of the design of an early expansion engine that has been widely used to liquefy helium. The expansion piston is driven in a reciprocating motion by a crank mechanism connected to a fly wheel and generator/motor. The intake valve is opened with the piston at the bottom of the stroke (minimum cold volume) and high pressure gas drives the piston up which causes the fly wheel speed to increase and drive the generator. The intake valve is closed before the piston reaches the top and the gas in the expansion space drops in pressure and temperature. At the top of the stroke the outlet valve opens and gas flows out as the piston is pushed down, driven by the fly wheel as it slows down. Depending on the size of the fly wheel it may continue to drive the generator/motor to output power or it may draw power as it acts as a motor.
The inlet and outlet valves are typically driven by cams connected to the fly wheel as shown in U.S. Pat. No. 3,438,220 to S. C. Collins. This patent describes a mechanism, which is different from the earlier patent, that couples the piston to the fly wheel in a way that does not put lateral forces on the seals at the warm end of the piston.
U.S. Pat. No. 5,355,679 to J. G. Pierce describes an alternate design of the inlet and outlet valves which are similar to the '220 valves in being cam driven and having seals at room temperature.
U.S. Pat. No. 5,092,131 to H. Hattori et al describes a Scotch Yoke drive mechanism and cold inlet and outlet valves that are actuated by the reciprocating piston. All of these engines have atmospheric air acting on the warm end of the piston and have been designed primarily to liquefy helium, hydrogen and air. Return gas is near atmospheric pressure and supply pressure is approximately 10 to 15 atmospheres. Compressor input power is typically in the range of 15 to 50 kW.
Lower power refrigerators typically operate on the GM, pulse tube, or Stirling cycles. Higher power refrigerators typically operate on the Brayton or Claude cycles using turbo-expanders. U.S. Pat. No. 3,045,436, by W. E. Gifford and H. O. McMahon describes the GM cycle. The lower power refrigerators use regenerator heat exchanges in which the gas flows back and forth through a packed bed, gas never leaving the cold end of the expander. This is in contrast to the Brayton cycle refrigerators that can distribute cold gas to a remote load.
The amount of energy that is recovered by the generator/motor in the '220 Collins type engine is small relative to the compressor power input so mechanical simplicity is often more important than efficiency in many applications. U.S. Pat. No. 6,202,421 by J. F. Maguire et al describes an engine that eliminates the fly wheel and generator/motor by using a hydraulic drive mechanism for the piston. The inlet valve is actuated by a solenoid and the outlet valve is actuated by a solenoid/pneumatic combination. The motivation for the hydraulically driven engine is to provide a small and light engine that can be removably connected to a superconducting magnet to cool it down. The claims cover the removable connection.
U.S. Pat. No. 6,205,791 by J. L. Smith describes an expansion engine that has a free floating piston with working gas (helium) around the piston. Gas pressure above the piston, the warm end, is controlled by valves connected to two buffer volumes, one at a pressure that is at about 75% of the difference between high and low pressure, and the other at about 25% of the pressure difference. Electrically activated inlet, outlet, and buffer valves are timed to open and close so that the piston is driven up and down with a small pressure difference above and below the piston, so very little gas flows through the small clearance between the piston and cylinder. A position sensor in the piston provides a signal that is used to control the timing of opening and closing the four valves.
If one thinks of a pulse tube as replacing a solid piston with a gas piston then the same "two buffer volume control" is seen in U.S. Pat. No. 5,481,878 by Zhu Shaowei. FIG. 3 of the '878 Shaowei patent shows the timing of opening and closing the four control valves and FIG. 3 of the '791 Smith patent shows the favorable P-V diagram that can be achieved by good timing of the relationship between piston position and opening and closing of the control valves. The area of the P-V diagram is the work that is produced, and maximum efficiency is achieved by minimizing the amount of gas that is drawn into the expansion space between points 1 and 3 of the '791 FIG. 3 diagram relative to the P-V work, (which equals the refrigeration produced).
The timing of opening and closing the inlet and outlet valves relative to the position of the piston is important to achieve good efficiency. Most of the engines that have been built for liquefying helium have used cam actuated valves similar to those of the '220 Collins patent. The '791 Smith, and '421 Maguire patents show electrically actuated valves. Other mechanisms include a rotary valve on the end of a Scotch Yoke drive shaft as shown in U.S. Pat. No. 5,361,588 by H. Asami et al and a shuttle valve actuated by the piston drive shaft as shown in U.S. Pat. No. 4,372,128 by Sarcia.
An example of the multi-ported rotary valve similar to the ones that are described in the present invention is found in U.S. patent application 2007/0119188 by M. Xu et al. U.S. Pat. No. 6,256,997 by R. C. Longsworth describes the use of "O" rings to reduce the vibration associated with the pneumatically actuated piston impacting at the ends of the stroke. This can be applied to the present invention.
Patent application Ser. No. 61/313,868 dated Mar. 15, 2010 by R. C. Longsworth describes a reciprocating expansion engine operating on a Brayton cycle in which the piston has a drive stem at the warm end that is driven by a mechanical drive, or gas pressure that alternates between high and low pressures, and the pressure at the warm end of the piston in the area around the drive stem is essentially the same as the pressure at the cold end of the piston while the piston is moving. Tests of the pneumatically actuated version of this concept have shown that it is not necessary to alternate the pressure on the stem between high and low to cause the piston to reciprocate but rather it is possible to maintain the pressure on the stem at low pressure. This simplifies the construction of the engine because it is now only necessary to actuate the cold high and low pressure valves.
Patent application Ser. No. 61/391,207 dated Oct. 8, 2010 by R. C. Longsworth describes the control of a reciprocating expansion engine operating on a Brayton cycle, as described in the previous application, that enables it to minimize the time to cool a mass to cryogenic temperatures.

SUMITOMO (SHI) CRYOGENIC OF AMERICA, INC.


Described herein is an improved, commercially viable and industrially advantageous process for the preparation of paliperidone intermediate 9-hydroxy-3-(2-chloroethyl)-2-methyl-4h-pyrido[1,2-a]pyrimidin-4-one and its hydrochloride salt. The process provides the paliperidone intermediate in higher yield and reduced reaction time compared to the previously disclosed processes, thereby providing for production of paliperidone and its pharmaceutically acceptable acid addition salts in high purity and in high yield.

U.S. Pat. Nos. 4,804,663 and 5,158,952 disclose a variety of 3-piperidinyl-1,2-benzisoxazole derivatives, processes for their preparation, pharmaceutical compositions comprising the derivatives, and methods of use thereof. These compounds have long-acting antipsychotic properties and are useful in the treatment of warm-blooded animals suffering from psychotic diseases. Among them, paliperidone, (±)-3-[2-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperidinyl]ethyl]-6, 7,8,9-tetrahydro-9-hydroxy-2-methyl-4H-pyrido [1,2-a]pyrimidin-4-one, is an antipsychotic agent and indicated for the both acute (short-term) and maintenance (long-term) treatment of schizophrenia. Paliperidone is represented by the following structural formula:

Processes for the preparation of paliperidone and related compounds are disclosed in U.S. Pat. Nos. 5,158,952, 5,254,556 and 5,688,799.
In the preparation of paliperidone, 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one of formula I:
is a key intermediate. According to U.S. Pat. Nos. 5,158,952 (hereinafter referred to as the '952 patent) and 5,254,556 (hereinafter referred to as the '556 patent), the compound of formula I can be prepared by the reaction of an optionally protected 2-aminopyridine compound with an α-acyl lactone compound in the presence of an activating reagent and in a suitable reaction-inert solvent such as toluene at a temperature 90° C. followed by treatment with ammonium hydroxide. The activating reagents include halogenating reagents such as, for example, phosphoryl chloride, phosphoryl bromide, phosphorous trichloride, thionyl chloride, and preferably phosphoryl chloride. The reaction mass is extracted with the solvents such as trichloromethane and then subjected to column chromatographic purifications.
The compound of formula I obtained by the process described in the '952 and the '556 patents is generally not of satisfactory purity. Unacceptable amounts of impurities are generally formed during the reaction between the 2-aminopyridine compound and the α-acyl lactone compound when the reaction is carried out in the presence of solvents like toluene, thus resulting in a poor product yield. In addition, the reaction proceeds at higher temperatures, and the process involves the additional step of column chromatographic purifications. Methods involving column chromatographic purifications are generally undesirable for large-scale operations, thereby making the process commercially unfeasible.
According to the U.S. Pat. No. 5,688,799 (hereinafter referred to as the '799 patent), the compound of formula I is prepared by the reaction of 2-amino-3-hydroxypyridine with 2-acetylbutyrolactone in the presence of p-toluenesulfonic acid in xylene solvent at reflux temperature for overnight using a water separator to yield 9-hydroxy-3-(2-hydroxyethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one. The 9-hydroxy-3-(2-hydroxyethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one is converted into its hydrochloride salt, followed by reaction with thionyl chloride in dimethylformamide to produce 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one.
The synthetic route for the compound of formula I as described in the '799 patent involves a lengthy process, the yields obtained in this process are very low, and also the process produces a product of unsatisfactory purity. This process is also commercially unfeasible. Moreover, the intermediate compound 9-hydroxy-3-(2-hydroxyethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one obtained in this process is poorly soluble in xylene, resulting in deposit formation on the wall of the reaction vessel and discoloration of the reaction mixture to black. Furthermore, the reaction with thionyl chloride is characterized by a very severe smell, likely caused by reaction of residual 2-acetylbutyrolactone remaining from the previous step. The process generally results in a product of unreproducible yield and quality.
PCT Publication No. WO 2006/027370 describes a modified process for preparation of 9-hydroxy-3-(2-hydroxyethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one involving the reaction of 2-amino-3-hydroxypyridine with 2-acetylbutyrolactone in the presence of p-toluenesulfonic acid and using chlorobenzene as a solvent at reflux temperature, i.e., at 125° C. The product is isolated by a process involving the addition of alcoholic solvent and filtration of the reaction mixture at 90-95° C.
The process described in WO 2006/027370 involves a lengthy process, the reaction proceeds at a high temperature i.e., above 125° C., it takes 19 hours for reaction completion, and also involves the hazard of filtration of a reaction mixture containing flammable solvents at 90-95° C. which poses problems in scale up operations. Based on the aforementioned drawbacks, this process may be unsuitable for preparation of the compound of formula I at laboratory scale and commercial scale operations.
A need remains for an improved and commercially viable process of preparing the compound of formula I or an acid addition salt thereof that will solve the problems associated with the processes described in the prior art, and that will be suitable for large-scale preparation. Desirable process properties include reduced reaction times, and greater simplicity, purity and yield of the product, thereby enabling the production of paliperidone and its pharmaceutically acceptable acid addition salts in high purity and in high yield.

Process for preparation of 9-hydroxy-3-(2-chloroethyl)-2-methyl-4H-pyrido[1,2-A]pyrimidin-4-one hydrochloride


A power switch with an independent light-emitting chamber includes a housing, a press-key, a power assembly, at least one light-emitting unit, and a circuit board. The housing is provided therein with a partition wall that divides the interior of the housing into a first receiving space and a second receiving space. The press-key and the power assembly can be disposed in the first receiving space. The press-key can bring the power assembly into a power-off state or a power-on state. The light-emitting unit can be disposed in the second receiving space and thereby turn the second receiving space into an independent light-emitting chamber. The circuit board can be disposed in the housing and electrically connected to the power assembly and the light-emitting unit. The power switch is enhanced in safety as the partition wall keeps the light-emitting unit and the power assembly from each other and hence from short-circuiting.

The emergence of various kinds of electrical equipment has formed a closer and closer bond between people's daily lives and such equipment. Generally, a power switch is used to control the electric current running through the electric device in order to turn on and off an electric device with ease to bring the electric device into a state in which electric current is allowed to flow to and power the electric device or a state in which electric current is cut off from the electric device. To increase the safety of use, a power switch may be provided therein with a trip element. The trip element automatically trips in response to an overcurrent and thereby cuts off the supply of electric current to ensure the user's safe use of electricity.
A conventional power switch is briefly described as follows. Referring to FIG. 1, the power switch 1 includes a housing 11, a press-key 12, a first electrically conductive plate 131, a second electrically conductive plate 132, a metal plate 14, a C-shaped spring plate 15, a third electrically conductive plate 133, and a light-emitting unit 16. The housing 11 is provided therein with a receiving space 111. The top side of the housing 11 is provided with an opening 112 that is in communication with the receiving space 111. The press-key 12 is pivotally arranged at the inner edge of the opening 112. The bottom side of the press-key 12 is provided with a first pushing portion 121 adjacent to one end of the press-key 12, and a second pushing portion 122 adjacent to the other end of the press-key 12. The pushing portions 121 and 122 are configured to extend into the receiving space 111.
Referring again to FIG. 1, the first electrically conductive plate 131 is fixedly provided at the housing 11 and is adjacent to a lateral side of the housing 11. The top end of the first electrically conductive plate 1311 is located in the receiving space 111 and is provided with a first contact point P1. The bottom end of the first electrically conductive plate 131 can extend out of the housing 11. The second electrically conductive plate 132 is also fixedly provided at the housing 11. The top end of the second electrically conductive plate 132 can be located in the receiving space 111 while the bottom end of the second electrically conductive plate 132 can extend out of the housing 11. The metal plate 14 has one end fixed at the top end of the second electrically conductive plate 132 and has a free end extending toward the side where the first electrically conductive plate 131 lies. Referring to FIG. 1, the metal plate 14 is formed with a generally U-shaped groove so as to form an elastic plate 142. The free end of the elastic plate 142 extends toward the second electrically conductive plate 132 and can be displaced to the top side or the bottom side of the groove when the free end of the metal plate 14 is or is not subjected to an applied force respectively. The elastic plate 142 is provided with a second contact point P2 adjacent to the free end of the elastic plate 142. The second contact point P2 corresponds to the first contact point P1 in position.
With continued reference to FIG. 1, the C-shaped spring plate 15 has one end that can be engagingly connected to the free end of the elastic plate 142 and the other end engagingly connected to the end of the metal plate 14 that is connected to the second electrically conductive plate 132. The C-shaped spring plate 15 corresponds to the first pushing portion 121 in position. When the first pushing portion 121 is displaced downward, the C-shaped spring plate 15 can be pushed by the first pushing portion 121 and in turn drive the free end of the elastic plate 142 downward to form an electrical connection between the second contact point P2 and the first contact point P1. When the second pushing portion 122 is displaced downward, the free end of the metal plate 14 can be pushed by the second pushing portion 122 and hence displaced downward, generating an elastic restoring force that makes the free end of the elastic plate 142 spring upward; as a result, the first contact point P1 and the second contact point P2 are separated from each other. The third electrically conductive plate 133 is fixedly provided at the housing 11 and is adjacent to another lateral side of the housing 11. The top end of the third electrically conductive plate 133 can be located in the receiving space 111 while the bottom end of the third electrically conductive plate 133 extends out of the housing 11. The light-emitting unit 16 is located in the receiving space 111 and lies under the press-key 12. The two electrode leads 161 of the light-emitting unit 16 can be electrically connected to the second electrically conductive plate 132 and the third electrically conductive plate 133 respectively. The light-emitting unit 16 is supplied with electricity and emits light when the first contact point P1 and the second contact point P2 are electrically connected.
In practical use, however, the power switch 1 still has its issues. Referring again to FIG. 1, the power switch 1 generally has a compact design with a small volume such that the space inside the housing 11 is rather limited. To save space, the electrode leads 161 of the light-emitting unit 16 are usually bent as shown in FIG. 1. If an assembly worker inadvertently bends the electrode leads 161 to an excessive degree and brings the electrode leads 161 into contact with the C-shaped spring plate 15, a short circuit will be formed. It follows that a lot of time and effort are required for adjusting the electrode leads 161 during the assembly process, e.g., by pulling the electrode leads 161 laterally apart to avoid contact with the C-shaped spring plate 15. The additional adjustment not only hinders the assembly process from being automated, but also lowers the yield of the power switch 1.
Moreover, when the press-key 12 is pressed multiple times in a back-and-forth manner, the light-emitting unit 16 tends to he shaken slightly as a result. If the shaking takes place repeatedly over a long time, the electrode leads 161 may be brought closer to, and eventually form a short circuit with, the C-shaped spring plate 15, which is dangerous. Accordingly, how to resolve the foregoing issues effectively and provide the public with a safer product is one of the important issues to be addressed by the present disclosure.

Power switch with independent light-emitting chamber


Embodiments of the present application relate to a search method, a system for searching, and a computer program product for searching. A search method is provided. The method includes receiving a query word string, retrieving a plurality of various product information entries related to the query word string, extracting, from a memory, a first core product word from the query word string, extracting, from the memory, second core product words from the various product information entries, for each second core product word, checking a list of candidate product words relating to a key product word for a presence of the each second core product word, in the event that the each second core product word is present, reducing a weighting of the product information entry corresponding to the each second core product word, and sorting the product information entries according to the adjusted weightings of the product information entries.

In a search process and particularly in a search process relating to products, due to different combinations of product words and in response to a certain product word entered by a user, a search engine may return peripheral products which are not highly related to a product relating to the product word entered by the user. For example, in response to the user entering MP3, the number of product word combinations corresponding to MP3 is very large. For example, products such as MP3 download cables and MP3 speakers may be found, but MP3 download cables and MP3 speakers are different products from MP3s. Because traditional searching performs a search based on key product word matching methods, searches can very easily return peripheral products which are relatively loosely related to the product relating to the query word string entered by the user. For example, as described above, if the user enters MP3 as a query word string, MP3 download cables and MP3 speakers have very high weightings in the search results in the search performed by the search engine. In other words, a large number of product information entries having a low correlation to the product corresponding to the query word string are present near the top of sorted product information entries returned by the search engine.
Two conventional technical methods exist to resolve interference by peripheral products having a low correlation to the product relating to the query word string entered by the user, as described above:
In a first technical method, categories are used to avoid a large number of peripheral results being found in the search results. The first technical method typically includes the following: first, based on log information, click through rates of categories corresponding to the user's query word string are tabulated, and then corresponding category tendencies relating to the query word string are determined. Weightings of product information entries which do not belong to the relevant categories are lowered. In other words, the weightings of product information entries contained in the returned search results which do not relate to the relevant categories are lowered.
With this method, substantial problems exist with respect to accuracy. For example, if mobile telephone batteries are placed in the mobile telephone category for purposes of fraud by sellers who distribute product information, peripherals products (mobile telephone batteries) will appear when mobile telephones are searched. Additionally, if a query word string is related to a plurality of categories, when analyzing the tendencies of the categories related to the query word string, if the click through rate of a certain category related to the query word string is very low, then this category can be easily overlooked. Accordingly, it is very difficult for the search engine to recall all categories related to the query word string resulting in a low search accuracy.
In a second technical method, the method includes online manual review of search results. The manual review method is used to determine peripheral word sets corresponding to each product word. In other words, if peripheral words appear in the search results, the method can determine that this product information entry having the peripheral words should not appear in the search results.
Although the accuracy of the manual review method is very high, the method requires the expenditure of a large number of man hours to perform the review, resulting in high labor costs.


A retrofit security adapter for adding a security slot to a portable device, such as a portable electronic device (laptop computer or electronic organizer). The adapter is made of ABS plastic made from a plastic formulation into which fiberglass fiber fill has been added prior to molding. The desired range of fiber fill is in the range of about 20% to about 40%, with about 30% most preferable. The adapter is adhered to the portable device using any suitable adhesive.

The present invention relates generally to security products for portable devices, and more specifically it relates to an adapter for retrofitting a valuable portable device with a security slot.
Portable devices, such as laptop computers, personal organizers and the like, are frequently the subject of theft. Consequently, Kensington.RTM. Microware Limited developed and promulgated a security slot standard for use with its MICROSAVER.RTM. security lock. U.S. Pat. No. 5,327,752, U.S. Pat. No. 5,381,685, U.S. Pat. No. 5,502,989, U.S. Pat. No. 5,493,878, U.S. Pat. No. D347,987 and U.S. Pat. No. D346,733, each hereby incorporated by reference for all purposes, define various locking devices for interfacing to security slots that may be incorporated into the walls of portable devices, for example, laptop computers. The security locks have proven to be an effective deterrent to theft of the portable devices. Unfortunately, the security locks may not be used with devices that do not have a security slot. The KENSINGTON.RTM. standard slot is increasingly being incorporated into more and more portable devices.
Not every portable device is manufactured with a necessary security slot. As a consequence, it is desirable to develop a retrofit security slot adapter that may be used with a portable device to enable the security locks to secure the portable device. It is important that such retrofit adapters be attachable with minimal equipment and potential damage to the portable device. Once attached, the retrofit adapter must resist efforts to shear, pull, pry or otherwise remove the adapter from the portable device. In addition, the retrofit adapter should be made of a material sufficiently strong to retain the security lock within the security slot.
To satisfy these requirements, some early versions of adapters were made of metal adhered directly to the wall of a portable device. While being sufficiently strong, such adapters were too rigid. As a consequence, metal adapters must either be relatively large to provide enough surface area to adequately adhere to a portable device, or were prone to being sheared or pried from the wall of the portable device. As portable devices are reduced in size, it becomes increasingly impractical to use large metal adapters. In addition, metal adapters may be relatively more expensive to manufacture than adapters made from other material.
An improvement to metal-only adapters incorporates a flexible elastomeric spacer between the metal adapter and the electronic device. Two layers of adhesive, one between the adapter and the spacer, and one between the spacer and the electronic device provide improved flexibility and resistance to removal over the metal-only adapter.


Upon incompletion of abnormality detection of an air-fuel ratio sensor provided in an exhaust pipe of an engine during operation of the engine (steps S310 and S320), when the state of charge SOC of a battery is lower than a preset reference charge level Sref or when the accelerator opening Acc is not less than a preset reference opening Aref (steps S330 and S340), the abnormality detection is not performed (step S350). When the state of charge SOC of the battery is not lower than the preset reference charge level Sref and when the accelerator opening Acc is less than the preset reference opening Aref (steps S330 and S340), the abnormality detection is performed to identify abnormality or normality of the air-fuel ratio sensor based on an air fuel ratio AF output from the air-fuel ratio sensor (steps S360 to S420). The drive control cuts off a fuel supply to the engine, controls a motor to enable motoring of the engine, and ensures output of a torque demand to a driveshaft, while the abnormality detection is performed.

1. Technical Field
The present invention relates to a power output apparatus, a vehicle equipped with the power output apparatus, and a control method of the power output apparatus.
2. Related Art
One proposed structure of a power output apparatus has an oxygen sensor provided in an exhaust pipe of an engine mounted on a vehicle (see, for example, Patent Document 1). The power output apparatus of this proposed structure uses the oxygen sensor to measure the concentration of oxygen included in an exhaust gas of the engine and performs feedback control based on the measured concentration of oxygen to regulate the amount of fuel injected into the engine.
Patent Document 1: Japanese Patent Laid-Open No. 2006-63822

Power output apparatus, vehicle equipped with power output apparatus, and control method of power output apparatus


In a distributed network comprising a plurality of peer (as opposed to master-slave) computers, a method of file shadowing allows each peer computer to maintain copies of data entries originated by the other peer computers in near-real time. Each computer assigns a unique serial number to each entry, and forwards each entry with the serial number and an identification of itself to all the other computers. Each computer informs each other computer of the highest sequential serial number received from it, and each computer resends to each other computer all entries having serial numbers higher than that acknowledged by each other computer.

1. Field of the Invention
The invention pertains to distributed computer networks, particularly to enhancing the shadowing of files among peer control computers within such networks.
2. Description of the Prior Art
The invention is embodied in an EFTPOS (Electronic Funds Transfer/Point of Sale) system such as the one described in U.S. Pat. No. 4,879,716, "Resilient Data Communications System", issued Nov. 7, 1989 to McNally et al (hereinafter, "the McNally patent").
A large number of point-of-sale (POS) terminals are distributed over a very large geographical area, perhaps on the order of an entire continent. A communications network is provided which transports data over the entire geographical area, and all the POS terminals are connected to it, through telephone lines and intelligent line concentrators (called network access controllers, or "NACs"). Also connected to the communications network are computers operated by financial institutions.
The POS terminals are typically placed into service by merchants, who then accept transactions from consumers who carry plastic credit cards or debit cards which bear in machine-readable form an identification of a financial institution which maintains an account for the consumer, and an identification of that account. The primary function of the system is to forward from the POS terminals to the financial institution computers information identifying a consumer's account and a transaction the consumer wishes to make in that account, and to return from the financial institution to the POS terminal either an acceptance or rejection of that transaction.
A merchant wishing to place a POS terminal into service typically obtains the necessary equipment (the terminals and associated modems, etc.) from a "service provider" organization. Such an organization might have no role in the EFTPOS system beyond that of providing equipment, or larger merchants and financial institutions might function as service providers; in that case the latter role is kept separated from the former.
In addition to line concentrators for POS terminals and computers of financial institutions being connected to the communications network as described above, two other classes of equipment are connected to it which exist ancillarily to the system's aforementioned primary function: network management systems (NMSs), and management workstations (WSs). (WSs are not specifically discussed in the McNally patent, but are at the heart of SAFs 12 and are attached to NMSs 14 to provide an interface between operators and NMSs.)
NMSs are responsible for overall control and monitoring of the EFTPOS system; WSs are used by the network provider organization and service provider organizations to control and monitor particular equipment and communication paths for which they are responsible. As described in the McNally patent, the NACs can be dynamically reconfigured and can report their present status; operators and administrators at the WSs may enter commands to reconfigure the systems or commands requesting information on the current status of the systems. Commands originating at a WS are passed to an NMS for verification that the action or information requested is within the purview of the requesting organization, and are acted upon by the NMS following that verification.
The WSs and NMSs have software running in them to effect the entry of such commands and the responses to them. Each particular type of command typically invokes a particular path through the software, causing the execution of executable paths that are provided to perform particular functions required for a particular command. A software entity dedicated to a discrete function is known in the software arts as a "process".
WSs and NMSs are distributed throughout the geographical area served by the system. The NMS in a particular region of the geographical area generally exercises direct control and monitoring of the POS terminals and NACs in that particular region. A request pertaining to such a terminal or NAC and originating from a process in a WS or NMS in a different region must be forwarded over the communications network to a process in the NMS having cognizance of the target NAC, and a response must be forwarded back to the requesting process.
Should an NMS become unavailable other NMSs will be directed by operational personnel to assume its functions. In order to be prepared for such eventualities, critical information that may originate at any NMS at any time regarding the status of the network and its users must be disseminated to all NMSs as soon as possible.
The term `shadowing` is used to describe a process which seeks to maintain a second copy of a file identical to some declared subset of a first file. The second copy of the file normally exists in a different computer system from the first copy. It is accepted that, at any instant, the second copy may not be identical to the first due to delays introduced by the copying and transmission methods. The second copy has two important characteristics: It is usable even if it is not identical to the first copy; the shadowing process ensures that the second copy will eventually become identical to the first copy.
Prior-art methods of file shadowing are generally "master-slave" arrangements wherein an entity maintaining a master file periodically sends updates to one or more slave entities in order for them to update their files; in the event that the master fails, one of the slaves takes over as the new master. The updates being periodic, it must do so without benefit of new information since the last periodic update. The prior-art methods may become unworkable if the computers are to be regarded as peers, rather than a master and a slave or slaves.

Method of file shadowing among peer systems