A 1.45-W/mm, 30-GHz InP-channel power HEMT

The authors report the fabrication of the first AlInAs/InP power HEMT with a saturated power density of 1.45 W/mm, a maximum power-added efficiency of 24%, and a large signal gain of 6.2 dB at 30 GHz. The authors show that the estimated power performance of this device at the highest frequencies is better than for any three-terminal devices because the f_t of the power HEMT is high, even at high drain-source bias     

Metallization of polyimide film by wet process

The interfacial adhesion strength of metallized polyimide (BPDA/ODA/PDA) has been studied with respect to polyimide surface molecular structure, reactions during electroless nickel deposition, baking, copper electroplating, and thickness of polyimide film. Each factor is discussed in terms of its influence on the peel strength. For practical application, operation at optimized conditions for each step of the metallization process is essential for sustaining the mechanical integrity of the copper/polyimide laminate. © 1994 John Wiley & Sons, Inc.     

Quality attributes of jams from low-usage tropical fruits

The chemical, sensory and storage properties of jams produced from two low-usage tropical fruits are presented. High-solids jams, either singly or blends, were produced from mature-ripe pulps of African star apple (Chrysophyllum albidum) and African plum (Spondias mombin) using the open-kettle process. Analytical data on the apple and plum jams showed that values obtained for fruit contents (43–45%), soluble solids (68·6–68·9%), reducing sugar (35·6–40·6%) and pH (2·80–3·40) are within the range typical of table jams. Whilst sensory evaluation indicated that the apple jams were preferred to the plum jams, storage trials showed that the fruit jams maintained good stability even when stored at tropical ambient conditions.     

无线网络及变送器的设计与应用

有线总线通信系统在工业上已被广泛应用,结合兰州某油库自动化改造工程采用无线网络实例,从工程设计的角度介绍了无线网络及变送器的应用,无线网络拓扑结构图、具体的无线网络设计方案及配置。着重讨论了无线网关、多功能节点、移动工作站、无线仪表的设计、选址及安装注意事项、无线应用技术特点等。通过与有线网络对比分析了无线网络的优缺点,展望了无线网络及无线变送器的应用前景,对其未来的应用提出建设性意见。     

On the Effect of Liquid-State Diffusion on Isothermal Solidification Completion Time During Transient Liquid-Phase Bonding of Dissimilar Materials

A study of transient liquid-phase bonding (TLPB) of dissimilar materials consisting of a nickel-based superalloy and a cobalt material is performed. In contrast to the assumption that rapid atomic diffusion in the liquid would reduce the processing time, t_f, required to completely eliminate the liquid phase from the joint region through diffusional solidification, the occurrence of liquid-state diffusion significantly prolonged the processing time t_f. This finding is crucially important to the TLPB of dissimilar materials.     

The structural plasticity of the C terminus of p21Cip1 is a determinant for target protein recognition

The cyclin-dependent kinase inhibitory protein p21(Cip1) might play multiple roles in cell-cycle regulation through interaction of its C-terminal domain with a defined set of cellular proteins such as proliferating cell nuclear antigen (PCNA), calmodulin (CaM), and the oncoprotein SET. p21(Cip1) could be described as an intrinsically unstructured protein in solution although the C-terminal domain adopts a well-defined extended conformation when bound to PCNA. However, the molecular mechanism of the interaction with CaM and the oncoprotein SET is not well understood, partly because of the lack of structural information. In this work, a peptide derived from the C-terminal domain of p21(Cip1) that covers the binding domain of the three above-mentioned proteins was used to demonstrate that the C-terminal domain of p21 recognizes multiple ligands through its ability to adopt multiple conformations. The conformation is dictated by tertiary contacts rather than by the primary sequence of the protein. Our results suggest that the C-terminal domain of p21(Cip1) adopts an extended structure when bound to PCNA and probably when bound to the oncoprotein SET, but an alpha helix when bound to CaM.     

Effect of γ‐irradiation on post‐harvest ripening of plantain fruit (Musa paradisiaca) cultivars

Three plantain cultivars, Agbagba, Obino L'ewai and Cardaba, harvested at two stages of maturity, were irradiated at 0.1–1.0 kGy prior to storage under tropical ambient conditions. Post‐irradiation storage behaviour showed that plantain fruits at full three‐quarter grade were more responsive to irradiation treatment than at full grade maturity, while Cardaba, a type of cooking banana, showed the least response. Irrespective of varietal differences, irradiation to 0.5 kGy or higher caused severe tissue damage, softening and skin discolouration; however, γ‐irradiation at optimum dose range of 0.15–0.30 kGy effectively delayed ripening for 10–12 days in Agbagba and Obino L'ewai, respectively, without affecting respiratory pattern or fruit quality. © 1999 Society of Chemical Industry     

A World Wide Web-service to aid the development of AMBER parameters using analogy to standard parameters.

A World-Wide Web service has been constructed to assist the development of force field parameters extending the AMBER force fields. This service extracts parameters from the standard AMBER force field parameter databases. From a Web-based interface the user can choose between bond, angle and torsional parameters with certain constraints on element and/or atom hybridization. The software constructed for the purpose of finding appropriate parameters will locate standard AMBER force field parameters matching the user specification. For bond and angle parameters a scatter plot of the reference values against force constants is provided. This service has been produced to assist in extraction and evaluation of parameters that may be useful for molecules other than proteins and nucleic acids.     

Fabrication of in-situ synthesized ceramic reinforced Ni-based alloy composite coatings by reactive braze coating processing

In-situ synthesized ceramic such as TiC, Cr7C3 and Cr5B3 reinforced Ni-based alloy composite coating was fabricated on the surface of mild steel substrate by reactive braze coating processing with colloidal graphite, Cr, Ni, ferro-boron, Si and titanium powders as the raw materials at low temperature of 1 000 ℃, and a new kind of coating materials was developed. By means of SEM, EDS, XRD and surface hardness tester, the microstructures, phases, hardness and wear-resistance of the coating were analyzed, respectively. The results revealed that the coating was mainly composed of the ceramic in-situ synthesized reinforcement phases of TiC, Cr7C3 and Cr5B3 and the binder phases in-situ synthesized of Ni31Si12 and (Ni, Fe) solid solution; The ceramic reinforcement phases of TiC, Cr7C3 and Cr5B3 were randomly distributed in the binder phases of Ni31Si12 and (Ni, Fe) solid solution; The coating had about 15vol% pores and can possibly be applied as a self-lubrication coating; The coating and the substrate were integrated together by metallurgical bonding; The coating had a hardness up to 91-94HR15N.     

干滑动条件下45CrNi材料摩擦磨损规律研究

以某自行火炮底座传动箱摩擦副所用材料45CrNi为研究对象，考察了该材料在不同热处理状态下（530℃回火、380℃回火、830℃淬火及原始状态）组成摩擦副时的干滑动摩擦磨损特性。试验结果表明：530℃回火盘和摩始销组成摩擦配副时结合最好，具有较好的摩擦磨损性能，销试样磨损率最小；在较低速度下载荷是影响材料摩擦因数的主要因素，而速度对摩擦因数的影响较小；粘着磨损是材料配副磨损的主要形式。