Table of Content

31 December 1990, Volume 8 Issue 4

Previous Issue    Next Issue

Articles

ONE-SYMBOL NETWORK FUNCTIONS AND NUMBERSYMBOL SEPARATING ALGORITHM

DAI JIE, LI FENG

1990, 8(4):  283-291. 

Asbtract ( 412 )   PDF (531KB) ( 111 )  

Related Articles | Metrics

In this paper, the concept about one-symbol network functions is presentep and the separating form of node admittance matrices is founded. The formulas for calculating determinants, 1-cofactors, and 2-cofactors of node admittance matrices are derived by using the number-symbol separating algorithm. On this basis, the formulas for calculating one-symbol network functions are given. By using these formulas, we can obtain any network functions which make any component parameter a symbol. This is a polynomial complexity algorithm, so it is an efficient algorithm. Furthermore, it is convenient to realize this algorithm by computers. This algorithm is suitable to largenetworks.

MÖSSBAUER STUDY OF THE MICRO WAVE/MAGNETIC DESULFURIZATION OF YUTIANBAO COAL

WENG SIHAO, XU YONGXIANG, WANG ZHAOMING, ZHAO CHANGGEN, WANG JIE, YANG JIANKANG

1990, 8(4):  292-296. 

Asbtract ( 329 )   PDF (386KB) ( 94 )  

Related Articles | Metrics

The microwave/magnetic desulfurization is an attractive, novel and efficient physical method for coal cleaning. The Mössbauer spectrum of the coal sample after microwave irradiation shows that high-frequenoy selective heating of coal has transformed more than 50% nonmagnetic pyrite FeS₂ into moderately magnetic pyrrhotite Fe_1-xS (0 < x ≤ 0.125) which will enhance effectively magnetic separation of inorganic sulfur in coal, and into antiferro-magnetic troilite FeS. The ferrous sulfate FeSO₄ of weathered products derived from FeS₂ is probably oxidized first and then sulfidized. There are no traces of iron oxide in the spectrum.
The magnetization enhancement of coal after microwave exposure is clear. Mössbauer spectra of magnetic separa ted samples show that there are no Fe_1-xS, FeS and FeSO₄ in the non-magnetic fraction, but there is a little of pyrite. Consequently, a majority of inorganic sulfur in the run-of-mine coal has already been removed significantly.
Calculations from the spectra of the abovementioned samples indicate that a 24% reduction of inorganic sulfur in coal after microwave treatment and a 91% reduction after microwave irradiation/magnetic separation treatment have been obtained, respectively.

Au/GaAs AND Au/GaSb INTERFACE STUDY AT LOW COVERAGE BY KELVIN CPD MEASUREMENT

SHAO BINGXIAN

1990, 8(4):  297-302. 

Asbtract ( 335 )   PDF (405KB) ( 98 )  

Related Articles | Metrics

The interface study on Au/GaSb and Au/GaAs at monolayer coverage in the UHV system by the Kelvin CPD method is presented. There are big jumps on well cleaved GaSb and GaAs surfaces after initial sub-monolayer gold deposition. It is consistent with the fact that the Fermi level is pinning at the surface states at the very beginning of Au deposition of about 0.2ML, according to the photoemission measurements. The experiments on Au/n-GaAs interface show that there are significant photo-effects on the CPD value, particularly in the case of less than 1 ML Au being deposited.

INVESTIGATION ON SILICON WAFER DIRECT BONDING MECHANISM

TONG QINYI, XU XIAOLI

1990, 8(4):  303-308. 

Asbtract ( 613 )   PDF (921KB) ( 182 )  

Related Articles | Metrics

A silicon wafer direct bonding mechanism is proposed as follows. Silicon dangling bonds on the thermal oxidized silicon surface adsorb OH groups to form chemical bonds. A pair of these mirror-polisned silicon wafers in contact is attracted by van der Waal's force at room temperature. At 200-400℃, OH groups located on both surfaces interact, and interface silanol bonds are formed between two surfaces. The polymerization of silanol bonds takes place at a temperature above 800℃ to form siloxane (Si-O-Si) and water. Water molecules diffuse through the interface oxide to react with the bulk silicon. It results in an enhancement of bonding strength and in a local vacuum at uncontacted voids and contributes to the elimination of voids. Water molecular diffusion coefficient increases exponentially with temperature and there is a turning point around 1050℃ after which the increasing rate slows down significantly. Based on the above bonding mechanism, an optimized bonding process has been designed and 3" wafers have been directly bonded successfully 1-3μm CMOS devices using the SOI/SDB material have been fabricated and good performance has been shown. Typical values of electron and hole channel mobility at low drain voltage are 680 cm²/V. sec. and 320 cm²/V. sec., respectively.

STUDIES ON THE SYNTHESIS AND LUMINESCENCE PROPERTIES OF (Li,Ca,Gd) SiO₃:Eu, Bi LUMINOPHORS

LI BIN, TIAN YIGUANG, BAI YUBAI

1990, 8(4):  309-314. 

Asbtract ( 366 )   PDF (411KB) ( 85 )  

Related Articles | Metrics

The luminophors of silicate (Li, Ca, Gd) SiO₃:Eu, Bi were sythesised and luminescence properties of Bi³⁺, Eu³⁺, and Gd³⁺ ions were studied. The effects and regularities of Gd³⁺ ion on the luminescence of Eu³⁺ and Bi³⁺ ions were investigated. The study on the luminescence of silicates (Li, Ca, Gd) SiO₃:Eu, Bi shows that there are energy transitions from Bi³⁺ ion to Eu³⁺ ion and that Bi³⁺ ions act as both sensitizers and co-activators and that the spectral energy distribution of the luminophors depends on the Gd³⁺ ion content. It is shown that Gd³⁺ ion can greatly promote the sensitive effect of Bi³⁺ on Eu³⁺ and turn the main emission of Eu³⁺ ion from ⁵D₀-⁷F₁ to ⁵D₀-⁷F₂ transition as the condensations of Gd³⁺ ion increase.
Under UV excitation of 393 nm, the luminescence intensities of Eu³⁺ in Li_0.3Ca_0.4Gd_0.268SiO₃Eu_0.025Bi_0.007 are the same as or more than those of Y(V, P)O₄:Eu for either ⁵D₀-⁷F₁ or ⁵D₀-⁷F₂ transition emission. The experiment results show that the optimum synthesis conditions are 950℃ and 4hrs fired twice for Li_0.30 Ca_0.40 Gd_0.30SiO₃:Eu, Bi and that silicate Li_0.30 Ca_0.40 Gd_0.30 SiO₃ is an excellent host lattice to obtain efficient photoluminescent materials.

ELECTROCHEMICAL NUCLEATION AND GROWTH OF ZIRCONIUM FROM MOLTEN FLUORIDES

YE SHANGYUN, LI GUOXUN

1990, 8(4):  315-320. 

Asbtract ( 359 )   PDF (918KB) ( 126 )  

Related Articles | Metrics

The electrocrystal growing mechanism of zirconium during electroplating was thoroughly studied in the molten fluoride system consisting of K₂ZrF₆ dissolved in FLINAK (KF:NaF:LiF, 42.0:11.5:46.5 mol). Steady polarization experiments indicated that the electrodeposition of zirconium depended on the nature of the electrode materials used. In the case of vitreous carbon electrode, the early stage of metal deposition was shown to be controlled by an electrochemical nucleation process. Chronoampertric measurements showed that the potentiostatic growth transients corresponded with a process of instantaneous nucleation and subsequent hemispherical growth in the melt. It was indicated that zirconium deposit grew in the way of sorewflaw crystals. A filiform microstructure was demonstrated by X-ray diffraction in the zirconium deposit; the preferred orientation was along Zr<110>. In a word, the electrodeposition process of zirconium depended on the electrochemical technologic case and the zirconium deposit with different preferred orientations could be obtained according to the deposition process.

PHASE STRUCTURE AND CHARACTERIZATION OF (ZnGeP₂)_1-x(GaP)_2x SYSTEM

HE XIANCHANG, SHEN HESHENG

1990, 8(4):  321-325. 

Asbtract ( 311 )   PDF (988KB) ( 88 )  

Related Articles | Metrics

The phase structure and the characterization of the (ZnGeP₂)_1-x(GaP)_2x system have been investigated in this paper. The reason for some differences if Ga partly substitutes for Zn and Ge in the lattice is briefly discussed.

ELECTROCHEMICAL SYNTHESIS OF ORTHO AMINO TOLUENE AND A STUDY OF ITS CATHODIC REACTION MECHANISM

GUI WEIZHI

1990, 8(4):  326-332. 

Asbtract ( 308 )   PDF (404KB) ( 87 )  

Related Articles | Metrics

In this paper a new process for the electrochemical synthesis of ortho amino toluene and a study of its cathodic reaction mechanism are introduced. For the sake of seeking out an optimum electrolytic potential, polarization curves of the solutions must be determined before electrolysis. Its product yield andcurrent efficiency are 80% and 98% respectively.
From repeated trials, the author has deduced that its cathodic reaction mechanism is a three-step EEC, and has pointed out the relations between electro-synthesis and its electrode reaction mechanism.

THE INVESTIGATION OF THE HEAT EVOLUTION OF AN/IA/MA COPOLYMERIC FIBRE DURING THE INITIAL STAGES OF PYROLYSIS BY CDSC METHOD

ZHAO GENXIANG, XUANG XIOULAN

1990, 8(4):  333-337. 

Asbtract ( 320 )   PDF (359KB) ( 81 )  

Related Articles | Metrics

By the comparative differential scanning calorimetry (CDSC) method, the heat evolution of the acrylonitrile (AN)/itaconic acid (IA)/methl acrylate (MA) copolymeric fibre during the initial stages of pyrolysis was studied in nitrogen atmosphere. From the CDSC measurements, it was observed that the sharp intense exotherm, occurring on a temperature-programmed pyrolysis, was related to the reaction of nitrile groups in the fibre. A first order kinetic equation was deduced for the thermal degradation of the AN/IA/MA copolymeric fibre studied. Relevant kinetic parameters of exo-thermic process were obtainedand discussed. For the sample of Jilin Research Institute of Chemical Technology, it was shown that cyclization occurred mainly; the cyclization activation energy was calculated to be 91.030kJ/mol. and the apparent activation energy was determined. Wherefore, we believe that the results are valuable and may play an important role in the improvement of the operating condition of the stabilization of polyacrylonitrile (PAN) precursors on the industrial scale.

AN IMPROVED ELIMINATING-HIDDEN PARTS METHOD IN DRAWING A THREE-DIMENSIONAL GRAPH WITH THE COMPUTER

TANG ZHENGQUAN, XU JIAFANG

1990, 8(4):  338-342. 

Asbtract ( 346 )   PDF (312KB) ( 71 )  

Related Articles | Metrics

This paper relates an improved eliminating-hidden-parts method in the course of drawing a three-dimensional graph, and provides the flow chart for using this method.

DESIGN AND IMPLEMENTATION OF THE YANGTZE RIVER INFORMATION SYSTEM BASED ON COMPUTER

LI LAYUAN

1990, 8(4):  343-348. 

Asbtract ( 304 )   PDF (458KB) ( 99 )  

Related Articles | Metrics

The design principle and implementation techniques for the Yangtze River information system are discussed. First, we briefly describe the purpose and function of the system. We then present the hardware architecture, system software and application software for realizing the system. Finally, some conclusions are given.

A CYCLE RECOGNITION ALGORITHM FOR REASONING NETWORKS

WU XINDONG, FANG LUN

1990, 8(4):  349-353. 

Asbtract ( 385 )   PDF (310KB) ( 107 )  

Related Articles | Metrics

A reasoning network is a special directed graph. Efficiently recognizing possible cycles in reasoning networks is useful not only in electronic networks and graph theory but also in automated knowledge acquisition research of intelligent systems. This paper designs a cycle recognition algorithm for reasoning networks and implements it in Turbo-PROLOG language. The algorithm can also be used for general directed graphs.

Research Notes

BORONIZATION AND ITS EFFECT ON PROPERTIES OF THE COMPONENTS AFTER DRY GRINDING WITH CBN WHEELS

HU ZHONGHUI, YUAN ZHEJUN

1990, 8(4):  354-356. 

Asbtract ( 392 )   PDF (228KB) ( 104 )  

Related Articles | Metrics

In this paper the investigation on boronization and its influence on properties of the components after dry grinding with CBN wheels is reported. The tests show that the boronization takes place in dry grinding with CBN wheels. It can gincrease compressive residual stresses, microhardness, and wear-resistance of the ground surfaces. Much higher ground surface integrity can be obtained in dry rinding with CBN wheels.

TEMPERATURE DEPENDENCE OF CYCLOTRON MASS OF MAGNETO-POLARON AT FINITE TEMPERATURE

ZHAO GUOZHONG, GU SHIWEI

1990, 8(4):  357-361. 

Asbtract ( 360 )   PDF (318KB) ( 91 )  

Related Articles | Metrics

In this paper, the effective Hamiltonian of the interface magneto-polaron at low temperature is derived by means of Larsen's method. The ground state and first excited state energies and the cyclotron mass are calculated. It is shown that the cyclotron mass of the interface magneto-polaron increases with increasing temperature at finite temperature.

STUDIES OF VAPOR DEPOSITION EVAPORATED BY INTENSE PULSED-ELECTRON-BEAMS

HAN LIJUN

1990, 8(4):  362-366. 

Asbtract ( 328 )   PDF (697KB) ( 113 )  

Related Articles | Metrics

Thin films are deposited on the surface of the substrate in room temperature. For film deposition, the intense pulsed electron beams with power densities about 10⁹W/cm² produced by a multi-plate chamber have been used to irradiate the target to create the dense plasma with energetic ions of target elements. The processes of deposition have been described. The physicochemical properties and the structures of the films have been characterized by using AES, ESOA, TEM etc.. For such a film deposition method, a variety of applications is expected.

A STUDY OF DETERMINATION OF GOLD AT AN EXTRACTIVE CARBON PASTE ELECTRODE MODIFIED WITH ALKYL TERTIAL AMINE(N₂₃₅)

PENG TUZHI, SHI QINGZHAO, LU RONGSHAN

1990, 8(4):  367-370. 

Asbtract ( 319 )   PDF (271KB) ( 87 )  

Related Articles | Metrics

A carbon paste electrode chemically modified with alkyl tertial amine (N₂₃₅) is used for the selective accumulation of gold (Ⅲ). The calibration plots are linear for the 0.1~10mgL^-1 range and the detection limit is 0.07mgL^-1 This electrode has been used to measure gold concentration in soma mineral samples without preisolation. The preparation and the electrochemical properties of the electrode, and the mechanism of extraction and activation are studied.