Preparation and Characterization of Zeolite Beta with Low SiO_2/Al_2O_3 Ratio

Zeolite beta with a low SiO2/Al2O3 ratio was synthesized by a novel two-step process.The synthesized sample was characterized with XRD,SEM,FTIR,and N2 adsorption-desorption and solid-state MAS NMR.The results showed that aluminium species were inserted into the framework of zeolite beta.The BET surface area,volume,and particle size of the zeolite beta sample decreased with decreasing SiO2/Al2O3 ratio.Our process was proved an efficient route to synthesize zeolite beta with a low SiO2/Al2O3 ratio.     

A case-control study of lung cancer among Vietnam veterans

Because of concerns among veterans over Agent Orange exposure, the Department of Veterans Affairs (VA) has conducted a series of studies of specific cancers among Vietnam veterans. Lung cancer is the topic of investigation in this report. The VA's Patient Treatment File (PTF) was used to identify 329 Vietnam era veterans with a diagnosis of lung cancer made between 1983 and 1990. The PTF is a computerized hospitalized database of inpatient records, including patients' demographic data, and diagnoses. A record is created for each patient discharged from any one of the VA's Medical Centers. Variables abstracted from the military record include education, race, branch of service, Military Occupational Specialty Code, rank, and units served within Vietnam. Two hundred sixty-nine controls were randomly selected from the PTF file of men hospitalized for a reason other than cancer. A second control group numbering 111 patients with colon cancer was also selected from the PTF file. Data were also gathered on exposure to Agent Orange through the location of each individual ground troop veteran's unit in relation to an area sprayed and the time elapsed since that area was sprayed. The crude odds ratio between service in Vietnam and lung cancer was of borderline significance (odds ratio = 1.39 with 95% confidence interval = 1.01-1.92). The relationship disappeared when the confounder year of birth was considered. We conclude from these data that there is no evidence of increased risk in lung cancer associated with service in Vietnam at this time.     

Electroless plating of copper on polyimide films modified by surface grafting of tertiary and quaternary amines polymers

Argon plasma-pretreated polyimide (PI, Kapton^® HN) films were subjected to UV-induced surface graft copolymerization with N,N′-(dimethylamino)ethyl methacrylate (DMAEMA) and 2-(trimethylammonium)ethyl methacrylate chloride (TMMAC). The DMAEMA graft-copolymerized PI (DMAEMA-g-PI) surfaces were also quaternized and amino-functionalized with 3-bromopropylamine hydrobromide (the Q-DMAEMA-g-PI surfaces). The surface composition and the degree of quaternization of the graft-modified PI films were determined by X-ray photoelectron spectroscopy. The DMAEMA-g-PI, Q-DMAEMA-g-PI and TMMAC graft-copolymerized PI (TMMAC-g-PI) surfaces can be activated directly by PdCl₂, in the absence of prior sensitization by SnCl₂ (the ‘Sn-free’ activation process), for the subsequent electroless plating of copper. A shorter induction time for the electroless deposition of copper was found for the palladium-activated Q-DMAEMA-g-PI and TMMAC-g-PI surfaces than for the palladium-activated DMAEMA-g-PI surface. The T-peel adhesion strength of the electrolessly deposited copper with the Q-DMAEMA-g-PI surface was enhanced to above 6 N/cm, in comparison to only about 4 N/cm for the DMAEMA-g-PI surface, about 2.5 N/cm for the TMMAC-g-PI surface, or about 0.5 N/cm for the PI surface with argon plasma treatment alone.     

Cross-specialty linkage and extrapolation of resource-based relative value scales

We used the fluorescent labelled dopamine D1-receptor antagonist Bodipy-SCH 23390 for the cellular localization of D1-ligand binding sites in the retinae of different vertebrates (teleosts, Xenopus, turtle, rat and rabbit). Competition experiments with unfixed cryosections of fish retina were performed to characterize the binding conditions of Bodipy-labelled SCH 23390. Tissue bound [3H]SCH 23390 was displaceable with increased amounts of bodipy-SCH 23390. The pharmacological specificity of the D1 fluorescent antagonist was determined by competition experiments with an excess of unlabelled SCH 23390. This treatment significantly reduced the level of fluorescence of the retina confirming the specificity of the binding. We observed a homogeneously distributed fluorescence signal in both plexiform layers in unfixed cryosections of fish, frog, turtle, rat and rabbit. Similar staining intensities of both plexiform layers were found in frog, turtle, rat and rabbit retina. In teleosts, the label of the outer plexiform layer was markedly more intense. Non-specific label was associated with photoreceptor outer and inner segments. The specific labelling of both plexiform layers indicates a mismatch of dopamine releasing and D1-binding sites, and suggests a possible extrasynaptic localization of the D1-receptor. The physiological significance of the observed distribution of D1-ligand binding sites is discussed with respect to the role of dopamine in controlling adaptational processes in the retina.     

Study on phase behavior–impact strength relationship of unsaturated polyester/polyurethane hybrid polymer network

The phase behavior of a hybrid polymer network (HPN) composed of poly[(propylene glycol maleate)-co-(propylene glycol phthalate)] crosslinked with styrene and polyester–urethane crosslinked with methylene-bis-ortho-chloroaniline was examined. The correlation between phase separation and impact strength of the HPNs is discussed. The composition of HPNs has an effect on their properties.     

Parasitic Bipolar Junction Transistors in a Floating-Gate MOSFET for Fluorescence Detection

In this letter, we examined whether the parasitic bipolar junction transistors (BJTs) in the MOSFET fabricated by the standard CMOS process can play a role as a fluorescence detector. To suppress the action of two vertical parasitic BJTs, the gate and n-well were tied in the parasitic BJTs, and the body node was connected to the drain. The proposed device was compared with the inherent and the parasitic diodes in the MOSFET. It had 100 times higher photocurrents than the diodes in the MOSFET. In addition, it was applied for the detection of the fluorescent signal, and could detect near 10 nM of Alexa 546. Therefore, CMOS-process-compatible parasitic BJTs can be used as a photodetector in an integrated fluorescence detector.     

A novel bidirectional CMOS transceiver for chip-to-chip optical interconnects

A novel bidirectional complementary metal-oxide-semiconductor (CMOS) transceiver for chip-to-chip optical interconnects operating at 2.5 Gb/s is proposed, which shares the common block of a receiver and a transmitter on a single chip. The share of the common block of two circuits makes it possible to save 55% or 20% of power dissipation, depending on the operating mode. The chip in 0.18-/spl mu/m CMOS technology occupies an area of 0.82/spl times/0.82 mm/sup 2/, 70% of the total area of a typical unshared transceiver chip. The transmitting and receiving modes of operation show -3-dB bandwidths of 2.2 and 2.4 GHz and electrical isolations of -28 and -40 dB, respectively.     

悟

“悟”是一种对客观的事和物的一种感知,是对事和物获取了解、获取知效,是人们求得理解的一种启示、一种认识的过程。一般地说,“我对事和物,意在彻悟”,是指人们得到充分的悟性,特别对意、意义的悟,有的很快领会,有的要耗费时日,有的要经过一定的时间乃至终身。悟性就是理解的     

《建筑课》之一开学了

“对于建筑事业,没有什么比让全民的建筑意识提高更重要的事情了。”五十多年前,年轻的齐康对此深信不疑,如今已是古稀之年的齐老对此仍然耿耿于怀。对于青年一代的教育,他从未放松;传统与现代的比较、东方与西方差异的研究,他从未停止。从本期起,我们将连续刊登齐康系列文章《建筑课》。     

力量空间

设计师做自己办公空间设计往往想法很多,也很苛求。这种设计状态会令将来的作品显得杂乱、稚嫩, 容易出现“昏招”,或者流于刻板、拘谨、不灵动。我懂得调整自己的状态:有时记住自己是甲方,可以任意发挥,有时把它忘了,也就不必太苛求,以致经常改动设计,不坚决。由于急于搬迁的缘故,加之那时我正好出差在外,所以本案设计周期较短。几天时间在宾馆里伏案设计,倒给出了一个好的状态:略去许多泉涌的想法, 只抓住最好的,好比画者在做速写,把控大局。凭我个人的喜好和习惯,以及对设计公司办公空间的理解与思考,我在凝神中拔高自己,发现塑造一种力量空间会比较接近于表达设计师这种群体的周遭环境,无需过多地出招,无需捕捉人的眼球。力量是潜在的,它无处不在,闭着眼也能抓住你的心。我就这样确立了设计主旨。