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This work shows that the coercive voltage or coercive electric field, which is the voltage or electric field to make the net polarization zero in a ferroelectric capacitor, depends on the direction of the sweep voltage applied externally. The difference in the coercive fields is shown in a metalferroelectric polymer-metal as an imprint phenomenon after the polymer, poly(vinylidene fluorideco-trifluoroethylene), P(VDF-TrFE), was prepared by using a spin coating method. This imprint can induce a read/write failure in ferroelectric memory devices; hence, it is important to study the imprint for reliability. The difference in the coercive voltages increases as the thickness of the capacitors increases while the difference in the coercive fields, the coercive voltage normalized for thickness remains nearly constant for all thicknesses. In conclusion, the imprint phenomenon is derived not from inside the ferroelectric polymer but from charge injection into the electrode.

This study examined the effect of crystalline orientation and dopants such as Nb and Zn on the piezoelectric coefficient of sol-gel driven Pb1(Zr0.52Ti0.48)O3(PZT) and doped PZT thin films. Crack-free 1-μm-thick PZT and doped PZT thin films prepared by using 2-Methoxyethanol-based sol-gel method were fabricated on Pt/Ti/SiO2/Si substrates. The highly (111) oriented PZT thin films of pure perovskite structure could be obtained by controlling various parameters such as a PbTiO3 seed layer and a concentration of sol-gel solution. The Nb-Zn doped PZT thin films exhibited high piezoelectric coefficient which was about 50 % higher than that of undoped PZT thin film. The highest measured piezoelectric coefficient was 240 pC/N, which could be applicable to piezoelectrically operated MEMS actuator, sensor, or energy harvester devices.

This study examined the dependency of crystalline orientation and electric properties of sol-gel PZT film on hydrolysis, a seed layer and a concentration of sol-gel solution. The PZT thin films were prepared by using 2-Methoxyethanol-based sol-gel method and spin-coating on Pt/Ti//Si substrates. The 1--thick PZT films were coated and then fired in a furnace by direct insert method. The highly (111) oriented PZT film of pure perovskite structure could be obtained. We could control the degree of orientation by various parameters such as hydrolysis, a seed layer and a concentration of sol-gel solution. The highest measured remanent polarization, dielectric constant and piezoelectric coefficient are , 2808, and 159 pC/N, respectively.

In order to reduce the sun-burn effect in a sample of the bolometric material Nb:TiO2−x , oxygen annealing was carried out. This effect can be examined by comparing thermal stability test results between the as-deposited and oxygen-atmosphere-annealed samples under high-temperature exposure conditions. Structural studies confirm the presence of amorphous and rutile phases in the as-deposited and annealed samples, respectively. Composition studies reveal the offset of oxygen vacancies in the Nb:TiO2−x samples through oxygen-atmosphere annealing. The oxygen atoms were diffused and seemed to occupy the vacant sites in the annealed samples. As a result, the annealed samples show better thermal stability performance than the as-deposited samples. The universal bolometric parameter (β) values were slightly decreased in the oxygen-annealed Nb:TiO2−x samples. Although bolometric performance was slightly decreased in the oxygen-annealed samples, high thermal stability would be the most essential factor in the case of special applications, such as the military and space industries. Finally, these results will be very useful for reducing the sun-burn effect in infrared detectors.

The temperature-dependent resistance changing characteristics (thermistor behaviors) of a poly(3,4-ethylenedioxythophene):poly(4-styrenesulfonate) (PEDOT:PSS) thin film are investigated in the 30–100 °C range using Greek-cross and bar patterns. The PEDOT:PSS film was spin-coated onto a Si wafer passivated with a SiO 2 layer, and a conventional dry etching technique was used to pattern the PEDOT:PSS film in conjunction with a nitride etch mask layer. Cr/Au was used for the electrode material. It was found that the characteristic temperature ( T 0 ) and resistivity of the PEDOT:PSS film have an inversely proportional relationship with the number of coatings and the number of interfaces between multiply coated PEDOT:PSS layers. It was also found that as the number of coatings and the number of the interfaces increase, lower temperature-dependent resistance changes are observed. The temperature coefficient of resistance (TCR) value of 60 nm thick PEDOT:PSS film was slightly larger than or comparable to that of a conventional metal (Au or Pt) thermistor. The possibility of utilizing the PEDOT:PSS thin film in thermistor applications is discussed.

The Hsp90 and Hsp70 molecular chaperones play important roles in the folding and proper functioning of diverse cellular proteins, including transcriptional regulators and protein kinases. In yeast, several transcriptional regulators and protein kinases are known to be substrates for Hsp90 and Hsp70 molecular chaperones. The yeast heme activator protein Hap1 promotes transcription of many genes in response to heme. It requires Hsp90 and Hsp70 molecular chaperones for its activity to be precisely regulated by heme concentration. The mechanism by which molecular chaperones promote heme regulation of Hap1 activity is distinct from the mechanism by which molecular chaperones promote steroid signaling. Hsp70 and Hsp90 molecular chaperones act separately to promote Hap1 repression in heme-deficient cells and heme activation of Hap1 in heme-sufficient cells. Likewise, distinct Hap1 elements or domains act to mediate Hap1 repression and heme activation separately. In this review, we summarize the current knowledge about the molecular mechanism governing heme regulation of Hap1 activity, and we compare this mechanism to the molecular mechanism by which Hsp90 and Hsp70 molecular chaperones promote the regulation of glucocorticoid receptor, the most extensively studied substrate of Hsp90 and Hsp70 molecular chaperones.

Nano to micro-sized patterns were formed on a flexible polymer substrate using a flexible UV imprint stamp. A 6in. diameter flexible UV nanoimprint template was fabricated using PVC hot embossing and DLC coating. Using the UV nanoimprint process with the DLC coated PVC template, nano to micro-sized patterns were clearly formed on the flexible PET substrate without a residual layer, due to the antistiction properties and high mechanical hardness of the DLC coating. By depositing a Cr layer on the imprinted resist pattern and lifting it off, Cr metal patterns were fabricated on the PET substrate.

In this paper, Poly(3, 4-ethylenedioxythiophene): Poly (Styrenesulfonate) (PEDOT: PSS) thin films for application in a bolometer, a type of uncooled infrared image sensor, are presented. In addition, the TCR and 1/ƒ noise dependencies of PEDOT: PSS thin films on the thermal treatment conditions are demonstrated. It is also shown that an appropriate thermal treatment can suppress the 1/ƒ-> noise of PEDOT: PSS thin films while maintaining the resistivity and TCR. A high TCR value over -4%/°C (within 10ohm·cm) through chemical treatment is also presented. The results of this study show that PEDOT: PSS thin films have potential for use as a bolometric material.

A new readout integrated circuit is developed for application in an amorphous silicon-based microbolometer array with a pixel pitch of 35µm. The proposed circuit lowers the power dissipation for a pixel-level analog-to-digital converter (ADC), which uses a comparator and a counter for its data conversion. The infrared current of a microbolometer is proportional to the resistivity changes of the microbolometer. Thus, the required number of counter operations for the pixel ADC can be determined according to the microbolometer current variation. The counting number precisely determines how much infrared flux is absorbed. A 14bit counter should normally be used for the pixel ADC for this kind of operation. However, when the proposed current skimming scheme is adopted, the total bits for the counter in the pixel ADC can be reduced to 12bits. Due to the proposed mechanism, the required operational speed of the comparator can lower than that of a conventional circuit. Consequently, the overall power dissipation in the comparator and counter is less than that of a conventional structure. This low power approach is very suitable in the pixel-level ADCs of microbolometers.

A new capacitive infrared detector structure that incorporates one electrically floated top electrode that acts as an infrared absorber and two bottom electrodes is proposed and fabricated. The concept begins from an attempt to remove metal lines, the main heat transfer media in the thermal-type infrared detector, from the device's thermal insulation section. A thermal insulation section can be composed without metal lines and instead be solely comprised of an insulator having very low thermal conductivity compared to metals. Therefore, low thermal conductance can be easily achieved with small dimensions of thermal insulation section material. The floating electrode is electrically disconnected from the substrate. Instead, the capacitance change is read only using the two bottom electrodes, which are separated from the absorber and placed on the substrate. The position of the top electrode (infrared absorber) is changed through a bimorph actuation in accordance with the absorption of LWIR (8–12 μm) rays, with an absorptance of 70%. This approach provides an enlarged fill-factor (25%) compared with earlier devices, because the portion of the leg in the pixel area is reduced, whereas the portion of the absorber area is increased. With the small dimension of the thermal insulation section (0.2 × 2 × 10 μm 3 ), thermal conductance of 1.27 × 10 −7 W/K is achieved. In addition, the shortened leg lends the device a higher spring constant relative to the conventional devices, and therefore a higher signal reading voltage can be achieved, resulting in increased temperature responsivity. With the bimorph-type infrared detector's characteristics of low noise and high sensitivity, the proposed structure can achieve a low NETD value of 12.7 mK.

An investigation of the output characteristics of Nd:YAG lasers operating at a wavelength of 1444 nm using a Xe-flashlamp of 450 Torr, a Xe-flashlamp of 700 Torr, and a Kr-flashlamp of 700 Torr is reported. The highest electrical-to-optical conversion efficiency of 1.83% was attained using the Kr-flashlamp of 700 Torr with a repetition rate of 20 Hz, a pumping pulse width of 144 μs, and an input energy of 31.7 J. The investigation concluded that output energy depends on the temperature of cooling water. The results showed a 3% decrease in output energy at an input energy of 31.7 J as the temperature of cooling water was increased from 23 to 38 °C.

Changes of free sugar on Gugija-sugar leaching were investigated by adding sugar on Gugija (Lycii fructus) raw fruit. Gugija were prepared by parboiling (40～50 sec at hot water of 85 o C) and unparboiling. Gugija-sugar leaching were leached after preserving (5 and 10 months at 5 o C) Gugija-sugar mixture (ratio of raw Gugija and sugar, 1:0.2, 1:0.4, 1:0.6, 1:0.8, and 1:1/w:w). Soluble starch content of Gugija-sugar leaching increased with increasing ratio of sugar without reference to parboiling treatment, having the highest content, 2.5% at UPRGSL-4 (unparboiling Gugija:sugar, 1:0.8 leaching). Maltose content increased with increasing ratio of sugar in PRGSL, being the highest at 12.66% in PRGSL-5 (parboiling Gugija:sugar, 1:1 leaching) at 10 months leaching periods. Most of the sucrose went out of existence with increasing leaching periods; content was 4.22% on PRGSL-5 and 1.36% on UPRGSL-5. Content of glucose and fructose increased with increasing ratio of sugar; glucose content was 7.86% on PRGSL-4 and 26.22% on UPRGSL-5, at 10 months leaching periods. Fructose content was 18.46% on PRGSL-5 and 22.51% on UPRGSL-4 at 10 months leaching periods. Contents of sorbitol and glycerol increased with increasing ratios of sugar.

A Nd:YAG laser pumped by a Kr-flashlamp with simultaneous dual-wavelength operation at 1357 nm (4F3/2 → 4I13/2(R1 → X4)) and 1444 nm (4F3/2 → 4I13/2(R1 → X7)) is demonstrated and its characteristics was analyzed. The output energy of 82 mJ at 1357 nm and 138 mJ at 1444 nm were achieved simultaneously with the maximum electrical input energy of 44 J. Stability of the output energy in the dual-wavelength operation was 1.41% at the maximum input energy of 44 J. However, the stabilities at each wavelength in the dual-wavelength operation showed much lower stability.

The evaluation test of various thin film contact materials for reliable radio frequency (RF) microelectromechanical systems (MEMS) switches is presented. Given that two of the most important performance criteria of RF MEMS switches are a low contact resistance and high reliability, the purpose of this study is to search for feasible contact materials and combinations by measuring the contact resistance and hot switching reliability under high current condition. We selected gold, platinum, and iridium for the contact materials and compared the contact resistance and failure point for various similar or dissimilar contacts; Au/Au, Pt/Pt, Ir/Ir, Au/Pt, and Au/Ir using a contact measurement apparatus. Also, we investigated the insertion loss and power handling capability of Au/Au and Au/Ir in the RF MEMS switches. From these studies, it was found that dissimilar contacts such as Au/Pt or Au/Ir are an effective means of enhancing the reliability for high power RF MEMS switches. This evaluation method represents an important step toward the development of reliable metal contacts.

Physicochemical properties of Gugija-sugar leaching were investigated by adding sugar ratio on Gugija (Lycii fructus) raw fruit. Gugija were prepared by parboiling (40～50 sec at 85 o C) and unparboiling. Gugija-sugar leaching were leached after preserving (5 months at 5 o C) Gugija-sugar mixture (20, 40, 60, 80 and 100% sugar based on raw Gugija). The yield increased with UPRGSL-4 (Gugija-sugar leaching adding 80% sugar) having the highest yield at 77.5%; in contrast, total acidity decreased with increasing ratio of sugar. The main organic acids of raw Gugija are tartaric acid (0.63%), citric acid (0.57%), malic acid (0.54%) and succinic acid (0.3%). Citric acid and succinic acid decreased with increasing ratio of sugar but malic acid and tartaric acid increased on Gugija-sugar leaching. Polyphenolics and betaine content of unparboiling Gugija-sugar leaching decreased as increase ratio of sugar but in term of used Gugija amount, betaine content of each Gugija-sugar leaching was equal to raw Gugija. Also, parboiling Gugija-sugar leaching decreased quickly with increasing ratio of sugar, especially PRGSL-4 and PRGSL-5 (parboiling Gugija-80 and 100% sugar leaching, respectively) was not determined. 15 types of free amino acids were detected in raw Gugija; the total content was 601.6 mg/100 g and the highest amino acid among them was serine, 218.1 mg/100 g. In PRGSL-4 prepared by parboiling, 9 kinds of free amino acid were detected and the total content was 383.3 mg/100g. Also, in UPRGSL-4 (unparboiling Gugija-80% sugar leaching), all 17 kinds were detected and its total content was 705.7 mg/100 g.

For real time image processing, a readout circuit for an infrared focal plane array (IRFPA) involving a new edge detection technique has been proposed in this letter. A non-uniformity correction unit (NUC), essential in an IRFPA because of bad non-uniformity characteristics of IR sensors is eliminated in this circuit by using a noise tolerant edge detection technique. In addition, real time edge detection can be possible, because of pixel-level integration and parallel processing. The proposed readout circuit shows an approximately three to nine times better edge error rate than other available methods using pixel-level parallel processing.

The yeast transcriptional regulator Hap1 promotes both transcriptional activation and repression. Previous studies have shown that Hap1 binds to the promoter of its own gene and represses its transcription. In this report, we identified the DNA site that allows Hap1 binding with high affinity. This Hap1-binding site contains only one CGG triplet and is distinct from the typical Hap1-binding upstream activation sequences (UASs) mediating transcriptional activation. Furthermore, at the HAP1 promoter, Ssa is bound to DNA with Hap1, whereas Hsp90 is not bound. Intriguingly, we found that histone deacetylases, including Rpd3, Hda1, Sin3 and Hos1, are not required for the repression of the HAP1 gene by Hap1. Rather, they are required for transcriptional activation of the HAP1 promoter, and this requirement is dependent on the HAP1 basal promoter. These results reveal a complex mechanism of transcriptional regulation at the HAP1 promoter, involving multiple DNA elements and regulatory proteins.

This paper presents the design, fabrication, and characterization of shunt type ohmic RF MEMS switches actuated by piezoelectricity. Since the proposed RF MEMS switches are actuated by piezoelectricity, they can be operated at an extremely low operation voltage of 5 V with a negligible power consumption of less than 0.1 μW. The proposed switches are primarily composed of piezoelectric cantilever actuators, a contact electrode and coplanar wave transmission lines suspended over the substrate. Unlike existing series type switches, the RF signal line of the shunt type ohmic switches is directly connected from the RF input port to the RF output port without any discontinuity, and their contact electrode is interconnected to all grounds. In this work, we consider three different types of RF MEMS switches in order to find the best geometry. The RF MEMS switch with one piezoelectric cantilever (Type-A) shows very poor isolation characteristic although it has better insertion loss than the others. The other two RF switches, which employ four piezoelectric cantilevers (Type-B and Type-C), differ in terms of the configuration of the cantilevers and the centered contact electrode. One has a centered contact electrode of square shape (Type-B), while the contact electrode of the other switch has a diamond shape (Type-C). They show relatively good isolation characteristics even at a very high frequency of 20 GHz, since the use of four piezoelectric cantilevers can generate a sufficiently large contacting force between the contact electrode and the RF signal line. The two fabricated RF MEMS switches have isolations of −23.0 and −24.0 dB, respectively, at an operation voltage of 5 V and a frequency of 20 GHz. The power-handling capability of the proposed RF MEMS switches increases to 1.4 W when an Iridium thin film coating is applied on the gold contact electrode.

In this article, silicon bulk micromachined RF MEMS switch with four cantilever piezoelectric actuators has been designed, fabricated, and characterized for advanced mobile/wireless communication systems. The proposed switch is comprised of four piezoelectric cantilever actuators, a contact metal pad, and a suspended CPW signal line above the silicon substrate. The fabricated piezoelectric switch has an insertion loss of −0.23 dB and an isolation of −44 dB at a frequency of 2 GHz and an operation voltage of 2.5 V, respectively. Also, it has constant performance characteristics at the certain range of applied voltages above the operation voltage that result in high production yield. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 570–573, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22195

A SAR ADC implemented with Dummy Gate-Assisted (DGA) n-MOSFET is presented with a custom-designed capacitor. The prototype chip was implemented using a commercial 0.35um CMOS process and intended for space applications requiring high resolution, low power consumption, and moderate conversion speed. The expected power consumption was 45.96uW at 3.3V supply. The measured SNDR and SFDR of the fabricated chip were about 66.6dB and 75.9dB, respectively. In order to evaluate its radiation tolerance, the fabricated chip was exposed to 60Co gamma-ray with a total radiation dose up to 300krad (Si), which corresponds to the total dose in geostationary orbit for 5 years. Although the ADC implemented using the conventional n-MOSFET completely lost its functionality after radiation exposure, the ADC implemented using DGA n-MOSFET exhibited good tolerance with regard to the total ionizing dose effect.

A new n-MOSFET layout on a bulk silicon substrate proposed for TID and SEE radiation tolerance combing a DGA n-MOSFET and a guard drain. The proposed n-MOSFET layout consists of a p+ and a p-active layer on the source-to-drain sidewall to prevent the development of a leakage path between the source and the drain, a dummy gate on the side drain/source to avoid the development of a leakage path between two MOSFETs, and a guard drain on the side dummy gate to reduce the SEE effect. The proposed n-MOSFET layout was found to eliminate all radiation-induced leakage current paths and to reduce SEE pulse to 35.36% in comparison with the conventional n-MOSFET. The simulation results demonstrated that the proposed n-MOSFET structure on the bulk silicon substrate performs well even when the fixed charge density increases and energetic protons are injected. These results confirm that the proposed n-MOSFET on the bulk silicon substrate is radiation-tolerant.

Evolution of supramolecular chirality from self-assembly of achiral compounds and control over its handedness is closely related to the evolution of life and development of supramolecular materials with desired handedness. Here we report a system where the entire process of induction, control and locking of supramolecular chirality can be manipulated by light. Combination of triphenylamine and diacetylene moieties in the molecular structure allows photoinduced self-assembly of the molecule into helical aggregates in a chlorinated solvent by visible light and covalent fixation of the aggregate via photopolymerization by ultraviolet light, respectively. By using visible circularly polarized light, the supramolecular chirality of the resulting aggregates is selectively and reversibly controlled by its rotational direction, and the desired supramolecular chirality can be arrested by irradiation with ultraviolet circularly polarized light. This methodology opens a route to ward the formation of supramolecular chiral conducting nanostructures from the self-assembly of achiral molecules.

A simple optical system using a wedge prism instead of a scanner for continuous curvilinear capsulorhexis [CCC] was studied.

In this paper, a fully wafer-level packaged RF MEMS switch has been demonstrated, which has low operation voltage, using a piezoelectric actuator. The piezoelectric actuator was designed to operate at low actuation voltage for application to advanced mobile handsets. The dc contact type RF switch was packaged using the wafer-level bonding process. The CPW transmission lines and piezoelectric actuators have been fabricated on separate wafers and assembled together by the wafer-level eutectic bonding process. A gold and tin composite was used for eutectic bonding at a low temperature of 300 °C. Via holes interconnecting the electrical contact pads through the wafer were filled completely with electroplated copper. The fully wafer-level packaged RF MEMS switch showed an insertion loss of 0.63 dB and an isolation of 26.4 dB at 5 GHz. The actuation voltage of the switch was 5 V. The resonant frequency of the piezoelectric actuator was 38.4 kHz and the spring constant of the actuator was calculated to be 9.6 N m−1. The size of the packaged SPST (single-pole single-through) switch was 1.2 mm × 1.2 mm including the packaging sealing rim. The effect of the proposed package structure on the RF performance was characterized with a device having CPW through lines and vertical feed lines excluding the RF switches. The measured packaging loss was 0.2 dB and the return loss was 33.6 dB at 5 GHz.

A novel bolometer structure has been proposed to achieve high detectivity. The detectivity is inversely proportional to the thermal conductance of a bolometer, and most of the thermal conductance is due to a metal wire, the placement of which is necessary for the reading of a signal. However, the thermal conductance of the proposed bolometer was unaffected by the thermal conductance of a metal wire. This is because a movable signal bridge was employed to lower the thermal conductance, thereby yielding a thermal conductance of 4.13times10-8 W/K. A measured detectivity of up to 4.23times109 cmmiddotHz1/2/W was attained at room temperature

In this study, we investigated the effects of gamma radiation on ZnS/CdTe-passivated HgCdTe photodiodes that were fabricated with one of two different surface treatments using bromine, Br2, or hydrazine, N2H4. Unlike the ZnS-passivated HgCdTe photodiodes, the ZnS/CdTe-passivated HgCdTe photodiodes showed no degradation in resistance-area product at zero bias (R0A) values after gamma irradiation of up to 1 Mrad. However, there is a significant difference between the bromine- and hydrazine-treated samples. Regardless of the dose of gamma radiation, there was little change in the forward current characteristics of the hydrazine-treated diode in comparison with the conventional bromine-treated diode. The hydrazine-treated diode showed fairly uniform R0A values of >107 Ω-cm2 up to 1 Mrad of gamma irradiation, whereas the bromine-treated diode showed an abrupt change in R0A values from ∼106 Ω-cm2 to ∼107 Ω-cm2 after gamma irradiation. Therefore, for use in a gamma radiation environment, the best combination for high-performance HgCdTe photodiodes is a ZnS/CdTe passivant that has been treated with hydrazine.

In this paper, fully integrated film bulk acoustic resonators (FBARs) and filter have been designed, fabricated, and characterized by using silicon bulk micromachining technology. The fabricated resonator is comprised of aluminum nitride (AlN) piezoelectric material sandwiched by two molybdenum (Mo) electrodes on top of silicon nitride thin membrane. The developed AlN piezoelectric film has 1.9° of FWHM (full width half maximum) of rocking curve and approximately 70 Mpa in tensile stress on top of the Mo electrode. The fabricated FBAR has a quality factor of 1530 in size of 200 × 200 μm2, insertion loss of −0.45 dB, and return loss of −28 dB, respectively. The fabricated FBAR ladder type filter is comprised of 7 resonators with 3 resonators in series and 4 resonators in parallel. It has insertion loss of −3.2 dB and ripple of 0.4 dB in pass band, absolute attenuation of 40 and 50 dB at 1.6–1.875 GHz and 2.110–2.170 GHz, respectively. The size of the fabricated FBAR filter is 1.2 mm × 1.4 mm before packaging and 3 mm × 3 mm after packaging, respectively. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2230–2233, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21905

Excellent surface flatness of HgCdTe wafers is essential for fabricating large infrared focal plane arrays (IRFPAs) within the framework of a flip-chip bonding yield. However, liquid-phase epitaxy (LPE) HgCdTe wafers, which are widely used for IRFPAs, have inherent problems pertaining to surface flatness. In this study, we introduced a single-point diamond turning (SPDT) method for use in fabricating LPE HgCdTe photodiodes. The cutoff wavelength of the wafers is ~5 µm. The surface roughness of the LPE HgCdTe wafer has been substantially reduced but a type-converted defective layer was formed on the surface of the HgCdTe wafer after SPDT, which was confirmed using Hall and capacitance–voltage (C–V) measurements. The defective layer, however, was easily removed by bromine in methanol (Br–MeOH) etching. The fabricated photodiode showed a dynamic resistance–area product at the zero bias (R0A) value of ~1 × 104 Ω cm2 for a junction area of 30 × 30 µm2 at 80 K, which is equivalent to that of a conventional photodiode. The flip-chip bonding efficiency has been remarkably improved from 89.43% to 99.99% for 320 × 256 IRFPA at room temperature after SPDT.

A multiple integration method is reported that greatly improves the signal-to-noise ratio (SNR) for applications with a high-resolution infrared (IR) focal plane array. The signal from each pixel is repeatedly sampled into an integration capacitor and then output and summed into an outside memory that continues for n read cycles during each period of a frame. This method increases the effective capacity of the charge integration and improves sensitivity. Because a low-noise function block and high-speed operation of the readout circuit is required, a new concept is proposed that enables the readout circuit to perform digitization by a voltage skimming method. The readout circuit was fabricated using a 0.6-/spl mu/m CMOS process for a 64/spl times/64 midwavelength IR HgCdTe detector array. The readout circuit effectively increases the charge storage capacity to 2.4/spl times/10/sup 8/ electrons and then provides a greatly improved SNR by a factor of approximately 3.

A new readout circuit involving two-step current-mode background suppression is studied for two-dimensional long-wavelength infrared focal plane arrays (2-D LWIR FPAs). Buffered direct injection (BDI) and a feedback amplifier are used for the input circuit and background suppression circuit, respectively. The readout circuit has been fabricated using a 0.6-/spl mu/m 2-poly 3-metal CMOS process for a 64/spl times/64 LWIR HgCdTe IR array with a pixel size of 50 /spl mu/m/spl times/50 /spl mu/m. The simple pixel circuit has a very small skimming error of less than 0.3% and low noise characteristics for an adequate calibration range and integration time.

Transferring the image information in analog form between the focal plane array (FPA) and the external electronics causes the disturbance of the outside noise. On-chip analog-to-digital (A/D) converter into the readout integrated circuit (ROIC) can eliminate the possibilities of the cross-talk of noise. Also, the information can be transported more efficiently in power in the digital domain compared to the analog domain. In designing on-chip A/D converter for cooled type high density infrared detector array, the most stringent requirements are power dissipation, number of bits, die area and throughput. In this study, pipelined type A/D converter was adopted because it has high operation speed characteristics with medium power consumption. Capacitor averaging technique and digital error correction for high resolution was used to eliminate the error which is brought out from the device mismatch. The readout circuit was fabricated using 0.6 μm CMOS process for 128 x 128 mid-wavelength infrared (MWIR) HgCdTe detector array. Fabricated circuit used direct injection type for input stage, and then S/N ratio could be maximized with increasing the integration capacitor. The measured performance of the 14 b A/D converter exhibited 0.2 LSB differential non-linearity (DNL) and 4 LSB integral non-linearity (INL). A/D converter had a 1 MHz operation speed with 75 mW power dissipation at 5 V. It took the die area of 5.6 mm 2 . It showed the good performance that can apply for cooled type high density infrared detector array.

The yeast heme activator protein Hap1 binds to DNA and activates transcription of genes encoding functions required for respiration and for controlling oxidative damage, in response to heme. Hap1 contains a DNA-binding domain with a C6 zinc cluster motif, a coiled-coil dimerization element, typical of the members of the yeast Gal4 family, and an acidic activation domain. The regulation of Hap1 transcription-activating activity is controlled by two classes of Hap1 elements, repression modules (RPM1–3) and heme-responsive motifs (HRM1–7). Previous indirect evidence indicates that Hap1 may repress transcription directly. Here we show, by promoter analysis, by chromatin immunoprecipitation, and by electrophoretic mobility shift assay, that Hap1 binds directly to DNA and represses transcription of its own gene by at least 20-fold. We found that Hap1 repression of the HAP1 gene occurs independently of heme concentrations. While DNA binding is required for transcriptional repression by Hap1, deletion of Hap1 activation domain and heme-regulatory elements has varying effects on repression. Further, we found that repression by Hap1 requires the function of Hsp70 (Ssa), but not Hsp90. These results show that Hap1 binds to its own promoter and represses transcription in a heme-independent but Hsp70-dependent manner.

We investigated the operational characteristics of a Q-switched Nd:YAG laser, which has an unstable resonator with a GRM(Gaussian reflectivity mirror). With electrical input energy of 55 J, we obtained the fundamental energy of 470 mJ at 1064 nm and the frequency doubled energy of 280 mJ at 532 nm. The Top-Hat profile of the output beam was obtained at the near field, and beam divergence was 1.7 mard.

We fabricated pyrromethene 597(PM597) solid-state dyes which were dissolved in PMMA(poly- methylmethacrylate) and characterized the lasing characteristics. The laser was end-pumped by a frequency doubled Q-switched Nd : YAG laser. We obtained the slope efficiency of at lasing wavelength of 585 nm. We demonstrated the laser lifetime to be more than 100,000 shots with output energy of 250 mJ and repetition rate of 4 Hz by adding singlet oxygen quencher DABCO(1,4-diazabicyclo [2,2,2]octane) to the solid-state dye.

Fully integrated film bulk acoustic resonators and band pass filters using a bulk micromachining method have been designed, fabricated, and characterized. Aluminum nitride (AlN) has been used for a piezoelectric material and Molybdenum (Mo) was employed as top and bottom electrodes. Also, Ti seed layers were used in order to obtain highly c-axis oriented AlN piezoelectric films. The film bulk acoustic resonators fabricated with highly c-axis oriented AlN films showed good performances such as an effective mechanical coupling coefficient of 7.5% and a quality factor of 1530. The band pass filter consisted of seven film bulk acoustic resonators with a high quality factor exhibited a transmission loss of −3.2 dB, a ripple of 1.2 dB in pass band, and attenuation values of −38 dB and −49 dB at both band boundaries, respectively.

Molecular chaperones Hsp90 and Hsp70 control many signal transducers, including cyclin-dependent kinases and steroid receptors. The yeast heme-responsive transcriptional activator Hap1 is a native substrate of both Hsp90 and Hsp70. Hsp90 and Hsp70 are critical for the precise regulation of Hap1 activity by heme. Here, to decipher the molecular events underlying the actions of Hsp90 and Hsp70 in heme regulation, we purified various multichaperone-Hap1 complexes and characterized the complexes linked to Hap1 repression and activation by two-dimensional electrophoresis analysis. Notably, we found that in vitro Hap1 is associated continuously with Ssa and its co-chaperones, and this association is not weakened by heme. Heme enhances the interaction between Hap1 and Hsp90. In vivo, defective Ssa, Ydj1, or Sro9 function causes Hap1 derepression in the absence of heme, whereas defective Hsp90 function causes reduced Hap1 activity at high heme concentrations. These results show that continuous association of Hap1 with Ssa, Ydj1, and Sro9 confers Hap1 repression, whereas enhanced association of Hsp90 with the repressed Hap1-Ssa-Ydj1-Sro9 complex by heme causes Hap1 activation. This novel mechanism of chaperone action may operate to control the activity of other important signal transducers.

Cd0.9Zn0.1Te thin films were prepared by vacuum evaporation onto well-cleaned glass substrates maintained at 300, 373 and 473 K. X-ray diffraction studies revealed that the films have zinc blende structure with preferential (111) orientation. Raman peak of the room temperature deposited film appeared at 140.30 cm-1 and 159.65 cm-1 were for the transverse optic (TO) and longitudinal optic (LO) phonons respectively. The XRD patterns of the higher substrate temperature deposited films exhibited an improvement in the crystallinity of the films. The Raman peak intensity increases and the FWHM decreases for the films deposited at higher substrate temperature. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The pseudodielectric-function spectra, e(E) = e1(E) + ie2(E), of polycrystalline Cd0.9Zn0.1Te thin films in the 1.7–5.5 eV photon energy range were measured by spectroscopic ellipsometry. The measured dielectric function spectra reveal distinct structures at energies of the E1, E1 + Δ1 and E2 critical points due to interband transitions. The vacuum evaporated Cd0.9Zn0.1Te thin films exhibited zinc-blende structure with predominant (111) orientation. The rms roughness of the film evaluated by an ex-situ atomic force microscopy is 3.7 nm. Dielectric related optical constants, determined from the spectroscopic ellipsometry data are presented and analyzed. The optical constants of the film were also determined by using optical transmittance measurements, and results were discussed. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

For many rivers and streams, it has been observed that a single representative discharge may be used to determine the hydraulic geometry of a stable channel. This representative channel forming discharge has been given several names by different researche

Heme-responsive motifs (HRMs) mediate heme regulation of diverse regulatory proteins. The heme activator protein Hap1 contains seven HRMs, but only one of them, HRM7, is essential for heme activation of Hap1. To better understand the molecular basis underlying the biological significance of HRMs, we examined the effects of various mutations of HRM7 on Hap1. We found that diverse mutations of HRM7 significantly diminished the extent of Hap1 activation by heme and moderately enhanced the interaction of Hap1 with Hsp90. Furthermore, deletions of nonregulatory sequences completely abolished heme activation of Hap1 and greatly enhanced the interaction of Hap1 with Hsp90. These results show that the biological functions of HRMs and Hsp90 are highly sensitive to structural changes. The unique role of HRM7 in heme activation stems from its specific structural environment, not its mere presence. Likewise, the role of Hsp90 in Hap1 activation is dictated by the conformational or structural state of Hap1, not by the mere strength of Hap1-Hsp90 interaction. It appears likely that HRM7 and Hsp90 act together to promote the Hap1 conformational changes that are necessary for Hap1 activation. Such fundamental mechanisms of HRM-Hsp90 cooperation may operate in diverse regulatory systems to mediate signal transduction.

Mercury cadmium telluride (Hg1−xCdxTe or MCT) has been commonly used in devices for infrared (IR) detection. For the optimum performance of the device, a compatible surface-passivation technology that provides long-term stability is required. Using x-ray photoelectron spectroscopy (XPS), the present study examines the effects on Hg0.8Cd0.2Te passivated with CdTe and ZnS undergoing baking in vacuum at temperatures typically used for dewar bakeout. Spectra recorded as a function of depth in both cases clearly show out-diffusion of Hg from the substrate toward the surface, even before the bakeout. On baking in vacuum, dramatic changes are observed in the ZnS/MCT case with complete loss of Hg from the sample up to the tested depth of more than 1,000 A. Compositions of the HgCdTe matrix, formed after Hg out-diffusion, before and after the bakeout are also calculated at selected depths (from 250 A to 700 A), which is vital information from a device point of view, as it affects the bandgap of this narrow-band semiconductor.

Cd 0.96 Zn 0.04 Te thin films are deposited onto thoroughly cleaned glass substrates (Coming 7059) kept at room temperature by vacuum evaporation. The films are found to have good stoichiometry as analyzed by Rutherford Backscattering Spectrometry. The films exhibited zinc blende structure with predominant (111) orientation. The surface morphology of the films is studied by Atomic Force Microscopy. The rms roughness of the films evaluated by AFM is 3.7 nm. The pseudodielectric-function spectra, e(E) = e 1 (E) + i e 2 (E) at room temperature are measured by spectroscopic ellipsometry. The measured dielectric function spectra reveal distinct structures at energies of the E 1 , E 1 +Δ 1 and E 2 critical points. The band gap energy of the films measured by optical transmittance measurement is 1.523 eV. The PL spectrum of the films shows intense emission due to free and bound exciton recombination and no emission associated with crystal imperfection and deeper impurity levels. The PL line shapes give indications of the high quality of the layers.

Polycrystalline Cd 0.96 Zn 0.04 Te thin films are deposited onto glass substrates (Corning 7059) kept at room temperature by vacuum evaporation. The films exhibit zinc blende structure with predominant (1 1 1) orientation. The rms roughness of the films evaluated by atomic force microscope is 3.7 nm. The band gap energy of the films measured by optical transmittance measurement is 1.539 eV. The photoluminescence (PL) spectrum of the films shows intense emission due to free and bound exciton recombination and no emission associated with crystal imperfection and PL line shapes give indications of the high quality of the layers. These films have been implanted with properly mass analyzed Boron ions ( 10 B + ) and the effect of implantation has been analyzed by X-ray diffraction, Raman scattering and optical transmittance measurements and the results are explained on the basis of the implantation induced surface roughness and lattice disorder.

Structural and optical studies have been carried out on Cd0.96Zn0.04Te thin films implanted with mass analyzed boron ions (10B+). We have analyzed the properties of the as-deposited and 10B+ implanted Cd0.96Zn0.04Te thin films using X-ray diffraction, roughness measurement, Raman scattering and optical transmittance measurements. The optical band gap of the as-deposited film is 1.539 eV and the value is found to reduce with the increase in implantation dose. This was accompanied by a progressive reduction in the sharpness of the absorption band edge. Raman spectrum of the as-deposited film shows longitudinal optic and transverse optic modes, which arise from CdTe and ZnTe like vibrations. On implantation the FWHM as well as the relative peak intensity are found to be increased. These results are explained on the basis of the implantation induced surface roughness and lattice disorder.

Polycrystalline Cd0.96Zn0.04Te thin films prepared by vacuum evaporation onto thoroughly cleaned glass substrates kept at room temperature were implanted with mass-analyzed beams of 100 keV boron ions (10B+) at various doses ranging from 1012 to 1014 ions cm−2. The X-ray diffraction pattern of the as-deposited film shows zinc blende structure with a predominant orientation along the 〈1 1 1〉 plane. The implanted films show a decrease in the 〈1 1 1〉 peak intensity and increase in the full-width at half-maximum (FWHM) with implantation dose. The surface roughness (rms) of the as-deposited film evaluated by atomic force microscopy is 3.7 nm and the value of roughness is found to increase with implantation dose. Raman spectra of the as-deposited films show longitudinal optic (LO) and transverse optic (TO) modes, which arise from CdTe-and ZnTe-like vibrations. There is no significant change in the Raman peak position due to implantation but the FWHM is found to be increased. This is probably due to the implantation-induced lattice disorder. The relative intensity of the Raman peaks and the area under the peaks were found to increase with implantation dose. These results are explained on the basis of the implantation-induced surface roughness and lattice disorder.

In this letter, a formation method for uniform ferroelectric polymer thin film on very rough aluminum foil is introduced, and the performance characteristics of the film are characterized by hysteresis measurements. For a bending radius of 0.6 cm, the remanent polarization, coercive field and internal bias field are equal in a flat state. After bending 500 times repetitively with a bending radius of 1.1 cm, its performance was nearly constant. Therefore, the method proposed in this letter can be useful for the fabrication of high-quality flexible memory devices on a flexible and rough substrate.

Cd 0.96 Zn 0.04 Te thin films are deposited onto well-cleaned glass substrates (Corning 7059) kept at room temperature by vacuum evaporation. Rutherford backscattering spectrometry and X-ray diffraction techniques are used to determine the thickness, composition and crystalline structure and grain size of the films, respectively. The films exhibited zinc blende structure with predominant (111) orientation. The surface morphology of the films is studied by scanning electron microscopy and atomic force microscopy. The rms roughness of the as-deposited films is 3.7 nm. The Raman spectra of the films show longitudinal- and transverse-optical (LO, TO) modes, which arise from CdTe- and ZnTe-like vibrations. The photoluminescence spectrum of the films shows intense emission due to free and bound exciton recombination and no emission associated with crystal imperfection and deeper impurity levels. The pseudodielectric-function spectra, e ( E )= e 1 ( E )+ ie 2 ( E ), of the films are measured by spectroscopic ellipsometry at room temperature. The measured dielectric function spectra reveal distinct structures at energies of the E 1 , E 1 +Δ 1 and E 2 critical points.

Cd 0.96 Zn 0.04 Te thin films were prepared by vacuum evaporation onto glass substrates kept at room temperature. X-ray diffraction (XRD) studies revealed that the as-deposited films have zinc blende structure with preferential (1 1 1) orientation. Raman peak of the as-deposited film appeared between 139.88 and 163.40 cm −1 for the transverse optic and the longitudinal optic phonons, respectively. These films were implanted with 100 keV boron ions to various doses from 10 12 to 10 14 ions/cm 2 . The XRD patterns of the irradiated films exhibited a decrease in peak intensity and increase in the FWHM of the (1 1 1) peak. The Raman peak position did not change appreciably whereas the FWHM increases with the ion dose and the results are attributed to the effect of implantation-induced lattice damage.